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Table S3. Biomarkers for lung origin and colon origins. Table S4. IHC analysis of the outlier models

Supplemental Figure Legends

Figure S1. Comparison of gene expression within and between cancer types when the number of pairwise DEGs is 3000.

PDX list

Table S1. List of cell lines mentioned/described in this study

The Cancer Genome Atlas (TCGA) project has generated abundant genomic data for human cancers of various histopathology types and enabled exploring cancer molecular pathology per big data approach. We developed a new algorithm based on most differentially expressed genes (DEG) per pairwise comparisons to calculate correlation coefficients to be used to quantify similarity within and between cancer types. We systematically compared TCGA cancers, demonstrating high correlation within types and low correlation between types, thus establishing molecular specificity of cancer types and an alternative diagnostic method largely equivalent to histopathology. Different coefficients for different cancers in study may reveal that the degree of the within-type homogeneity varies by cancer types. We also performed the same calculation using the TCGA-derived DEGs on patient-derived xenografts (PDX) of different histopathology types corresponding to the TCGA types, as well as on cancer cell lines. We, for the first time, demonstrated highly similar patterns for within- and between-type correlation between PDXs and patient samples in a systematic study, confirming the high relevance of PDXs as surrogate experimental models for human diseases. In contrast, cancer cell lines have drastically reduced expression similarity to both PDXs and patient samples. The studies also revealed high similarity between some types, for example, LUSC and HNSCC, but low similarity between certain subtypes, for example, LUAD and LUSC. Our newly developed algorithm seems to be a practical diagnostic method to classify and reclassify a disease, either human or xenograft, with better accuracy than traditional histopathology. Cancer Res; 76(16); 4619–26. ©2016 AACR.

Cetuximab is an approved treatment for metastatic colorectal carcinoma (mCRC) with codon 12/13-KRAS mutations, recently questioned for its validity, and alternative mutation-based biomarkers were proposed. We set out to investigate whether an expression signature can also predict response by utilizing a cetuximab mouse clinical trial (MCT) dataset on a cohort of 25 randomly selected EGFR+ CRC patient-derived xenografts (PDXs). While we found that the expression of EGFR and its ligands are not predictive of the cetuximab response, we tested a published RAS pathway signature, a 147-gene expression signature proposed to describe RAS pathway activity, against this MCT dataset. Interestingly, our study showed that the observed cetuximab activity has a strong correlation with the RAS pathway signature score, which was also demonstrated to have a certain degree of correlation with a historic clinical dataset. Altogether, the independent validations in unrelated datasets from independent cohort of CRCs strongly suggest that RAS pathway signature may be a relevant expression signature predictive of CRC response to cetuximab. Our data seem to suggest that an mRNA expressing signature may also be developed as a predictive biomarker for drug response, similarly to genetic mutations.

Anecdote clinical observations hint that non-small cell lung cancer (NSCLC) with exon-20 insertions might respond poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), contrasting to those with classic mutations. Lack of patient-derived experimental models has been a major hurdle for the discovery of new treatment for the diseases. We established two NSCLC-PDXs harboring two different exon-20 insertions, LU0387-adenocarcinoma (ADC) with a nine-base insertion at 2319 (H773-V774insNPH) and LU3075-squamous cell carcinoma (SCC) with a nine-base insertion at 2316 (P772-H773insDNP). Both insertions immediately follow the regulatory C-helix of the kinase domain. Contrary to the generally good responses to EGFR inhibitors observed in PDXs with classic mutations, both exon-20 insertions are largely resistant to cetuximab and TKIs in vivo, suggesting fundamental difference from the classic EGFR mutations, consistent with the poor response rate to TKI seen in anecdotal clinic reports. It is worth noting that although responses are generally poor, they differ between the two exon-20 mutants depending on the type of TKI. In vitro drug sensitivity assays using established primary cell lines from our two PDXs largely confirmed the in vivo data. Our data from patient-derived experimental models confirmed that exon-20 insertions in domain immediately following the C-helix confer poor response to all known EGFR inhibitors, and suggested that these models can be utilized to facilitate the discovery of new therapies targeting NSCLC harboring exon-20 insertions.

// Dawei Chen 1 , Xuesong Huang 1 , Jie Cai 1 , Sheng Guo 1 , Wubin Qian 1 , Jean-Pierre Wery 1 , Qi-Xiang Li 1, 2 1 Crown Bioscience, Inc., 3375 Scott Blvd, Santa Clara, CA 95054, USA 2 State Key Laboratory of Natural and Biomimetic Drugs, Peking University, Beijing 100191, China Correspondence to: Qi-Xiang Li, e-mail: henryli@crownbio.com Keywords: biomarker, PDX, KRAS, erbitux, patient stratification Received: August 12, 2015 Accepted: September 28, 2015 Published: October 26, 2015 ABSTRACT Cetuximab is a standard of care for treating EGFR-expressing metastatic colorectal carcinoma (mCRC) exclusive of those with KRAS mutations at codons 12/13. However, retrospective analysis has recently suggested that KRAS-G13D patients can still benefit, while only a fraction of KRAS wild-type patients can benefit, from the treatment. We set out to test this contradicting issue experimentally in an independent cohort of patient derived xenograft (PDX) diseases. We conducted a mouse clinical trial (MCT) enrolling a random cohort of 27 transcriptome sequenced CRC-PDXs to evaluate cetuximab activity. The treatment responses were analyzed against the KRAS 12/13 mutation alleles, as well as several other well-known oncogenic alleles. If the response is defined by >80% tumor growth inhibition, 8/27 PDXs (~30%) are responders versus 19/27 non-/partial responders (~70%). We found that indeed there are no significantly fewer KRAS-12/13-allele responders (4/8 or 50%) than non-/partial responders (7/19, or 37%). In particular, there are actually no fewer G13D responders (4/8, or 50%) than in non-/partial responders (2/19 or 10.5%) statistically. Furthermore, majority of the non-/partial responders tend to have certain activating oncogenic alleles (one or more of the following common ones: K/N-RAS-G12V/D, -A146T, -Q61H/R, BRAF-V600E, AKT1-L52R and PIK3CA-E545G/K). Our data on an independent cohort support the recent clinical observation, but against the current practiced patient stratification in the cetuximab CRC treatment. Meanwhile, our data seem to suggest that a set of the six-oncogenic alleles may be of better predictive value than the current practiced stratification, justifying a new prospective clinical investigation on an independent cohort for confirmation.

The HuPrime® human gastric neuroendocrine carcinoma derived xenograft model GA0087 was established in this study. GA0087 PDX model showed high gene expression of vascular endothelial growth factors (VEGF)-A and B, and high potential of lung metastasis. Circulating tumor cells (CTCs) with either large or small size, circulating tumor microemboli (CTM) and lung metastatic lesions were detected in GA0087 PDX mice. The number of CTC correlated to the number of metastatic nodules in lung. Both primary tumor growth and metastasis in terms of the number of dynamically monitored CTCs and metastatic nodules were effectively suppressed by Cisplatin. Diverse subtypes of CTCs in the context of sensitivity to Cisplatin were specifically identified by subtraction enrichment (SE) integrated with in situ Phenotyping of cytokeratin 18 (CK18) and Karyotyping of chromosome 8 (in situ PK CTC by CK-iFISH). All the CK18-/diploid and majority of CK18+/diploid CTC subtypes were chemosensitive, whereas a higher percentage of CK18+/multiploid subtype of CTC were Cisplatin-insensitive. Combined histopathological examination of metastatic lesion and in situ PK CTC in a metastatic PDX (mPDX) tumor model are of particular significance, and may provide an unique and robust platform for cancer research as well as pre-clinical evaluation of therapeutic efficacy of new anti-cancer drugs.

Platinum-based chemotherapy, such as cisplatin, is the primary treatment for ovarian cancer. However, drug resistance has become a major impediment to the successful treatment of ovarian cancer. To date, the molecular mechanisms of resistance to platinum-based chemotherapy remain unclear. In this study, we applied an LC/MS-based protein quantification method to examine the global protein expression of two pairs of ovarian cancer cell lines, A2780/A2780-CP (cisplatin-sensitive/cisplatin-resistant) and 2008/2008-C13*5.25 (cisplatin-sensitive/cisplatin-resistant). We identified and quantified over 2000 proteins from these cell lines and 760 proteins showed significant expression changes with a false discovery rate of less than 5% between paired groups. Based on the results we obtained, we suggest several potential pathways that may be involved in cisplatin resistance in human ovarian cancer. This study provides not only a new proteomic platform for large-scale quantitative protein analysis, but also important information for discovery of potential biomarkers of cisplatin resistance in ovarian cancer. Furthermore, these results may be clinically relevant for diagnostics, prognostics, and therapeutic improvement for ovarian cancer treatment.

Anecdote clinical observations hint that non-small cell lung cancer (NSCLC) with exon-20 insertions might respond poorly to epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), contrasting to those with classic mutations. Lack of patient-derived experimental models has been a major hurdle for the discovery of new treatment for the diseases. We established two NSCLC-PDXs harboring two different exon-20 insertions, LU0387-adenocarcinoma (ADC) with a nine-base insertion at 2319 (H773-V774insNPH) and LU3075-squamous cell carcinoma (SCC) with a nine-base insertion at 2316 (P772-H773insDNP). Both insertions immediately follow the regulatory C-helix of the kinase domain. Contrary to the generally good responses to EGFR inhibitors observed in PDXs with classic mutations, both exon-20 insertions are largely resistant to cetuximab and TKIs in vivo, suggesting fundamental difference from the classic EGFR mutations, consistent with the poor response rate to TKI seen in anecdotal clinic reports. It is worth noting that although responses are generally poor, they differ between the two exon-20 mutants depending on the type of TKI. In vitro drug sensitivity assays using established primary cell lines from our two PDXs largely confirmed the in vivo data. Our data from patient-derived experimental models confirmed that exon-20 insertions in domain immediately following the C-helix confer poor response to all known EGFR inhibitors, and suggested that these models can be utilized to facilitate the discovery of new therapies targeting NSCLC harboring exon-20 insertions.

The Cancer Genome Atlas (TCGA) project has generated abundant genomic data for human cancers of various histopathology types and enabled exploring cancer molecular pathology per big data approach. We developed a new algorithm based on most differentially expressed genes (DEG) per pairwise comparisons to calculate correlation coefficients to be used to quantify similarity within and between cancer types. We systematically compared TCGA cancers, demonstrating high correlation within types and low correlation between types, thus establishing molecular specificity of cancer types and an alternative diagnostic method largely equivalent to histopathology. Different coefficients for different cancers in study may reveal that the degree of the within-type homogeneity varies by cancer types. We also performed the same calculation using the TCGA-derived DEGs on patient-derived xenografts (PDX) of different histopathology types corresponding to the TCGA types, as well as on cancer cell lines. We, for the first time, demonstrated highly similar patterns for within- and between-type correlation between PDXs and patient samples in a systematic study, confirming the high relevance of PDXs as surrogate experimental models for human diseases. In contrast, cancer cell lines have drastically reduced expression similarity to both PDXs and patient samples. The studies also revealed high similarity between some types, for example, LUSC and HNSCC, but low similarity between certain subtypes, for example, LUAD and LUSC. Our newly developed algorithm seems to be a practical diagnostic method to classify and reclassify a disease, either human or xenograft, with better accuracy than traditional histopathology. Cancer Res; 76(16); 4619–26. ©2016 AACR.

Engrafting the bone marrow cells of a patient with M5 acute myeloid leukemia into immunocompromised mice (AM7577) resulted in serially transferrable stable AML and eventual mortality. The disease starts in the bone marrow and then expands to peripheral areas, which is typical of M5 leukemogenesis, where high leukemic burden in blood is coincident with symptoms/mortality. The leukemic cells in the mice had myeloid morphology, phenotypes, and genotypes (including the internal tandem duplication of FMS-like tyrosine kinase receptor 3 gene [FLT3-ITD]) similar to those of the original patient. Autocrine mechanisms of human granulocyte–macrophage colony-stimulating factor/interleukin-3 likely support AM7577 growth in mice. Treatment with FLT3 TKI (AC220) caused complete remission in peripheral blood, spleen, and bone, along with relief of symptoms and extended life, hinting that FLT3-ITD may be a key leukemogenic driver maintaining the disease. Interestingly, withdrawal of AC220 (high dose) did not result in relapse of disease, suggesting cure. These results, however, are in contrast to cytarabine (AraC) induction treatment: First, although AraC significantly suppresses the diseases in blood, and to a lesser degree in bone marrow and spleen, the suppression is temporary and does not prevent eventual onset of disease/death. Second, the withdrawal of AraC always resulted in rapid relapse in peripheral blood and eventually death. Our observation in this patient-derived model may provide useful information for clinical applications of the two drugs.

Immune checkpoint inhibitors, i.e., PD1 and CTLA4 antibody therapeutics, have led to long-term survival in many late-stage solid tumor patients. Despite this revolutionary clinical impact, the overall response rate is still low. One major roadblock is that compensatory immune inhibitory pathways were turned on to protect tumor cells from being attacked by T cells. T cell immunoglobulin- and mucin domain-containing molecule 3 (Tim-3) is a type I transmembrane protein expressed in T cells, monocytes, macrophages, and dendritic cells. PD-1 and Tim-3 coexpression is often associated with an exhausted phenotype of tumor-infiltrating lymphocyte (TIL) in various tumor types. TIM-3 expression has been reported as a compensatory mechanism in the PD1 nonresponsive patients. Simultaneously targeting PD1 and TIM3 is now being actively tested in clinical trials. However, we still do not have an animal model that can efficiently evaluate the efficacy of therapeutic TIM3 antibodies or combinations. Here we report generation of a human TIM3 knock-in C57BL/6 mouse model, in which we replaced mouse exon 2-5 of HAVCR2 gene with human counterparts. The engineered knock-in mice express a chimeric TIM3 where its extracellular and transmembrane domains are human sequence, while the signal peptide and intracellular domain are kept intact. We confirmed that homozygous knock-in mice only express this chimeric TIM3, recognizable by human TIM3 antibody in NK cells, macrophages, and stimulated T cells. In an efficacy study, we inoculated the TIM3 knock-in mice with MC38 syngeneic tumor cells. Treating the mice with 5 mg/kg of human TIM3 antibody resulted in modest tumor growth inhibition (TGI), while in combination with anti-mouse PD1 antibody, the TGI improved to 62% following 2 weeks of treatment. We are now breeding the human PD1 and human TIM3 double knock-in mice to test the combinatory therapeutic antibodies. We have also developed human PD-L1 expressing MC38 cells, so that when inoculated in human TIM3 knock-in mice, PD-L1 and TIM3 therapeutic combination can be evaluated. Citation Format: Lei Zheng, Xuesong Huang, Wenyi Ouyang, Gang Chen, Annie Xiaoyu An, Xin Dong, Jay Liu, Jean Pierre Wery, Qian Shi, Davy Xuesong Ouyang. Generation of human TIM3 knock-in mice for preclinical efficacy assessment of therapeutic antibodies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A203.

Little progress has been made in treatment of acute myeloid leukemia (AML) for years. Following the success of immune checkpoint inhibitors in solid tumors, immunotherapy also offers huge promise in many hematologic malignancies, including AML. Anti-PD1 antibody is currently being investigated in combination with azacitidine in patients with relapsed AML. Other emerging immuno-oncology (I/O) therapeutics are also at different stages of preclinical research. However, we are lacking relevant animal models with intact immune system for the preclinical in vivo pharmacologic studies and mechanism-of-action analysis of I/O agents. To meet this need, we set out to develop a series of transplantable mouse AML models carrying Nras mutations and/or a set of clinical relevant fusion proteins, like AML1/ETO. Using a similar approach reported by Scott Lowe and colleagues (1), we constructed retroviral vectors expressing human AML1/ETO9a IRES GFP and NrasG12D, generated retroviruses, co-transduced the fetal liver cells, and performed syngeneic intravenous injections in C57BL/6 mice. The mice developed AML in the following months as the GFP-positive cells enriched as high as around 90% in PBMC. Leukemia cells also dominatde the spleen and bone marrow in moribund mice. The splenocytes from moribund AML1/ETO9a mice were banked and transplanted into new C57BL/6 mice for several rounds. The later passages were more malignant than the early passages. To validate the immune profiling of this model, FACS analysis was applied using mouse PD-L1, Gr-1, CD45, Mac-1, c-kit, and sca-1 antibodies for GFP-positive cells. In PBMC of moribund AML1/ETO9a mice, PD-L1 and c-kit were highly expressed, while the expression levels of Gr-1, CD45, Mac-1, and sca-1 were low. For efficacy test, we performed standard-of-care (SOC) assay with cytarabine, doxorubicin, sorafenib, and anti-PD1 antibody. The dosing started around 10 days post inoculation of 1 x 106 leukemia cells, when GFP-positive cells were 2-10%. While doxorubicin showed good response, cytarabine and sorafenib resulted in modest tumor growth inhibition, and anti-PD1 antibody failed to show any meaningful efficacy. We are currently testing more combinatory treatments, including anti-TIM3 and anti-CTLA4 antibodies. Taken together, we have developed a mouse AML model with clinical relevant mutations for preclinical efficacy assessment of combinatory chemotherapies, target therapies, and immunotherapies. Reference: 1. Zuber J, Radtke I, Pardee TS, et al. Mouse models of human AML accurately predict chemotherapy response. Genes Dev 2009. Citation Format: Xin Tang, Lily Tong, Annie Xiaoyu An, Likun Zhang, Jie Cai, Qian Shi, Jean Pierre Wery, Davy Xuesong Ouyang. Developing an AML mouse syngeneic model for combinatory chemotherapy and immunotherapy [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A003.

OX40 is a costimulatory molecule of TNF receptor family, primarily expressed on activated effector T cells and regulatory T cells. Engagement of OX40 by ligand leads to dramatic expansion, effector function, cytokine production, and survival of T cells. Several OX40-agonistic antibodies are in early stages of clinical development and some have shown promising antitumor immunity and improved tumor-free survival in the patients compared with standard-of-care therapies. Preclinical studies using surrogate OX40-agonistic antibodies have also shown robust tumor growth inhibition (TGI) efficacies, especially when combined with other checkpoint inhibitors like PD1 and CTLA-4 antibodies. However, we are lacking reliable preclinical models to assess the efficacy of human therapeutic antibodies. To address this need, we created a human OX40 knock-in GEMM (OX40 HuGEMM), where the entire 2.5 Kb mouse OX40 coding region is replaced by human OX40. We confirmed the expression of human OX40 in the 95% of activated T cells from the homozygous knock-in mice, while the mouse OX40 is completely eliminated. In the heterozygous knock-in mice, 58% of activated T cells express both mouse and human OX40. We then used both heterozygous and homozygous knock-in mice for efficacy studies of OX40 antibodies. In the heterozygous knock-in mice bearing MC38 syngeneic tumors, human and mouse OX40 antibody monotherapies led to 49% and 20% TGI, respectively, while their combination with PD1 antibody was synergistically effective, resulting in ~90% TGI with multiple complete tumor regressions. When we grafted the homozygous knock-in mice with B16F10 syngeneic tumors, single 5 mg/kg dose of an investigational human OX40 antibody led to 47% TGI. Tumor-killing efficacy of OX40 antibody is also correlated with significantly increased tumor infiltrated T cells and NK cells. Taken together, our OX40 HuGEMM provides an urgently needed tool for testing in vivo efficacy of human OX40 therapeutics, both as a single agent and as various combination strategies with other treatment modalities. Citation Format: Xuesong Huang, Lei Zheng, Wenyi Ouyang, Mingkun Zhang, Annie Xiaoyu An, Jing Zhao, Xiang Gao, Jean Pierre Wery, Qian Shi. Utilizing human OX40 knock-in mice (HuGEMMTM) to assess antitumor efficacy of OX40-agonistic antibodies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A207.

In the pharmaceutical industry today, many of the potent compounds discovered using expensive technologies are eventually rejected because of poor physicochemical or absorption, distribution, metabolism, excretion and toxicology (ADME/Tox) properties. This problem can be addressed by placing fast and accurate computational technologies at the heart of drug discovery. Chemically diverse and potent compounds generated by de novo design algorithms are scored for ADME/Tox properties using rigorously validated statistical models. Every molecule passing through this in silico pipeline is thus associated with a wealth of predicted properties, thereby allowing for rapid assessment to determine which molecule should be further developed. Critical to this idea is a platform that allows for the efficient exchange of in silico and experimental data between all scientists regardless of specialization. By bridging the gap between the in silico and experimental cultures in this fashion, an information-driven, cost-effective drug discovery program can be realized.

CD137 belongs to the TNF receptor super family, and its activation is essential to the function of T cells and NK cells. Multiple agonistic CD137 antibodies are currently being tested in humans with advanced cancer, which expected to become an important new immuno-oncology therapeutics in clinic. It is important to establish preclinical models for efficacy assessment of investigational CD137 antibodies before entering clinic. Currently available animal models cannot meet this need. Syngeneic mouse tumor models provide a useful platform for testing surrogate immuno-oncology therapies, but cannot be used for testing human therapeutic antibodies due to the species specificity; human immunity reconstituted models, by human PBMC or hematopoietic stem cell inoculation into immune deficient mice, suffering from highly variable responses, are not robust enough to provide a reliable system for efficacy studies. Establishing target humanized models by replacing mouse therapeutic target with human counterpart while maintaining normal mouse immunity is a practical approach to evaluate human therapeutic antibodies in vivo. Using CRISPR-Cas9 gene editing, we have engineered human CD137 knock-in model expressing chimeric human/mouse CD137 composed of human extracellular and transmembrane domains (Exon 4-7), with intact mouse signal peptide and intracellular domain. FACS analysis of splenocytes derived from homozygous knock-in mice showed that CD3/CD28 stimulated T cells only express chimeric CD137 reactive to human CD137 antibodies, but not mouse CD137; Yet the expression levels of the chimeric CD137 in the knock-in mice are generally lower than endogenous mouse protein in wild-type C57BL/6 mice. At present, we are testing the efficacy of reference human CD137 agonistic antibodies by treating these homozygous knock-in mice grafted with syngeneic MC38 tumor cells. Data will be presented at the conference. Citation Format: Davy Xuesong Ouyang, Gang Chen, Zhensheng Wang, Lei Zheng, Annie Xiaoyu An, Jean-Pierre Wery, Jay Liu, Xin Dong, Henry Q. X. Li. Establishment of CD137 humanized mouse model for efficacy assessment of agonistic anti-CD137 therapeutic antibodies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1658. doi:10.1158/1538-7445.AM2017-1658

A facility-based protein crystallization apparatus for microgravity (PCAM) has been constructed and flown on a series of Space Shuttle Missions. The hardware development was undertaken largely because of the many important examples of quality improvements gained from crystal growth in the diffusion-limited environment in space. The concept was based on the adaptation for microgravity of a commonly available crystallization tray to increase sample density, to facilitate co-investigator participation and to improve flight logistics and handling. A co-investigator group representing scientists from industry, academia, and government laboratories has been established. Microgravity applications of the hardware have produced improvements in a number of structure-based crystallographic studies and include examples of enabling research. Additionally, the facility has been used to support fundamental research in protein crystal growth which has delineated factors contributing to the effect of microgravity on the growth and quality of protein crystals.

Advances in experimental and computational techniques have reaffirmed the role of protein X-ray crystallography as one of the primary providers of structural information both to enhance our fundamental understanding of biological systems and also to assist the design and optimization of important therapeutics. Today, the most important challenge facing macromolecular X-ray crystallography is the need to grow suitable crystals of a given protein. Once this has been accomplished, most often the question is not whether the structure will be solved but rather how fast this will be done. A dramatic example of this is the crystal structure of cytochrome c oxidase. The search for crystallization conditions took about 15 years and then the structure was solved in about one year.

Mutations in the obese gene (OB) or in the gene encoding the OB receptor(OB-R) result in obesity, infertility and diabetes in a variety of mouse phenotypes. The demonstration that OB protein (also known as leptin) can normalize body weight in ob/ob mice has generated enormous interest. Most human obesity does not appear to result from a mutant form of leptin: rather, serum leptin concentrations are increased and there is an apparent inability to transport it to the central nervous system (CNS). Injection of leptin into the CNS of overfed rodents resistant to peripheral administration was found to induce biological activity. Consequently, for the leptin to act as a weight-lowering hormone in human obesity, it appears that appropriate concentrations must be present in the CNS. This places a premium on understanding the structure of the hormone in order to design more potent and selective agonists. Here we report the crystal structure at 2.4A resolution of a human mutant OB protein (leptin-E100) that has comparable biological activity to wild type but which crystallizes more readily. The structure reveals a four-helix bundle similar to that of the long-chain helical cytokine family.

A preclinical trial identified 4 of 20 (20%) gastric cancer (GC) patient-derived xenografts responded to cetuximab. Genome-wide profiling and additional investigations revealed that high EGFR mRNA expression and immunohistochemistry score (3+) are associated with tumor growth inhibition. Furthermore, EGFR amplification were observed in 2/4 (50%) responders with average copy number 5.8 and >15 respectively. Our data suggest that a GC subtype with EGFR amplification and overexpression benefit from cetuximab treatment.

As reported in our previous paper, a series of indole-3-acetamides which possessed potency and selectivity as inhibitors of human nonpancreatic secretory phospholipase A2(hnps-PLA2) was developed. The design of these compounds was based on information derived from x-ray crystal structures determined for complexes between the enzyme and its inhibitors. We describe here the further implementation of this structure-based design strategy and continued SAR development to produce indole-3-acetamides with additional functionalities which provide increased interaction with important residues within the enzyme active site. These efforts led to inhibitors with substantially enhanced potency and selectivity.

Phospholipases (PLAs) produce rate-limiting precursors in the biosynthesis of various types of biologically active lipids involved in inflammatory processes. Increased levels of human nonpancreatic secretory phospholipase A2 (hnps-PLA2) have been detected in several pathological conditions. An inhibitor of this enzyme could have therapeutic utility. A broad screening program was carried out to identify chemical structures which could inhibit hnps-PLA2. One of the lead compounds generated by the screening program was 5-methoxy-2-methyl-1-(phenylmethyl)-1H-indole-3-acetic acid (13a). We describe the syntheses, structure−activity relationships, and pharmacological activities of a series of indole-3-acetamides and related compounds derived from this lead. This SAR was undertaken with the aid of X-ray crystal structures of complexes between the inhibitors and hnps-PLA2 which were of great value in directing the SAR.

The recent clinical successes of immune checkpoint inhibitors have fueled the intense interest in novel immuno-oncology (I/O) therapeutics. The lack of relevant animal models remains a major hurdle in understanding the mechanism of action and evaluating the efficacy of such therapeutics. Patient derived xenograft (PDX), considered to most closely mimic patient tumors in both histo- and molecular pathology1,2, is however rarely used in I/O studies because it grow only in immune-compromised hosts. In reality, many PDXs grow well in nude mice where certain immune functions remain intact, excluding T-cells/T-cell functions. Therefore, PDX could still potentially be of practical use for studying T-cell independent I/O therapy. This study set out to evaluate a biologics for the treatment of a patient derived xenograft disease, by activating mouse natural killer (NK). NK and CD8 T cells are two major immune effector cell types that mediate cytotoxicity to tumor cells in vivo. One of the immunomodulatory agents, an anti-PD-L1 antibody-based IL-15 immunocytokine, was recently tested as a novel I/O treatment of cancer3. This molecule was engineered to be cross-species for both human and mouse PD-L1 and IL-15 that antagonize PD1/PD-L1 checkpoint-mediated immune suppression and also target the PD-L1-expressing tumor with IL-15 stimulated NK and CD8 T effector cells into local tumor sites, thus synergizing tumor-located anti-tumor immunity. In fact, our previous studies have demonstrated a greatly enhanced anti-tumor activity in the PDL-1-expressing syngeneic mouse tumor models via the mobilization of tumor infiltrating lymphocyte (TILs), over the PD-L1 antibody alone3. Since IL-15 also stimulates NKs in addition to T-cells, we reasoned that this bifunctional agent could also have potential activity against a PD-L1-expressing PDX in nude mice where NK remains functional. LU1901 is previously described NSCLC-PDX1, and was confirmed to express high level of PD-L1 by both RNAseq and flow analysis, after screening of a large panel of PDXs. We implanted LU1901 in Balb/c nude mice, and started to treat the mice by the bifunctional agent when the tumor reached to 150 mm3. Our result clearly demonstrated a significant inhibition of LU1901 growth by the bifunctional agent in nude mice, in the apparent absence of T-cells. When the treated tumors were examined at the termination, significantly infiltrate NK cells were found inside the treated tumors, as measured by both flow cytometry and immunohistochemistry (IHC). The number of infiltrating NK also statistically correlates to the amplitude of the tumor responses. Together, our data suggest that one of important mechanisms of action of this bifunctional agent relies on the tumor-targeting NK activation, and also that PDX could be a useful model suitable for in vivo efficacy analysis of T-cell independent immunotherapy. References 1. Yang, M., et al. Overcoming erlotinib resistance with tailored treatment regimen in patient-derived xenografts from naive Asian NSCLC patients. International journal of cancer. Journal international du cancer 132, E74-84 (2013). 2. Guo, S., Wubin Qian, Jie Cai, Likun Zhang, Jean-Pierre Wery, Qi-Xiang Li. Molecular pathology of patient tumors, patient derived xenografts and cancer cell lines EORTC-NCI-AACR. (2015). 3. Yan Wu, Zhaojing Zhong, Stella Martomo, Dan Lu, Zhanna Polonskaya, Xenia Luna, Haifan Zhang, Zhikai Zhang, Zhun Wang*, Leo Liu*, Jeegar Patel, James Tonra, Henry Li*, Larry Witte, Sam Waksal, Zhenping Zhu. Anti-PD-L1 antibody-based IL-15 immunocytokine has enhanced antitumor immunity. EORTC-NCI-AACR Abstract (2015). Citation Format: Henry Q. Li, Zhun Wang, Xiaoyu An, Jinping Liu, Likun Zhang, Jean-Pierre Wery, Yan Wu, James Tonra, Sam Waksal, Zhenping Zhu. Modeling an immunotherapy of NK mechanism on a NSCLC patient derived xenograft. [abstract]. In: Proceedings of the AACR Special Conference: Patient-Derived Cancer Models: Present and Future Applications from Basic Science to the Clinic; Feb 11-14, 2016; New Orleans, LA. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(16_Suppl):Abstract nr A30.

We previously generated the MuPrime® mBR6004 model, by engrafting the breast adenocarcinoma derived from MMTV-PyVT transgenic mice (GEMM)1 into the syngeneic FVB/N mice2,3. The allograft grows robustly, maintains the histopathology features of the original GEMM, and metastasizes to the lungs in all examined cases when implanted orthotopically2. Additionally, histopathology shows that the models is HER2++, but ER-/PR-. We profiled drug responses to standard of care (SoC)2 and checkpoint inhibitors3. Interestingly, among all checkpoints inhibitors tested, our model is insensitive to PD1/PDL-1 inhibitors, but responds to CTLA-4 inhibitors3. To further explore the underlying mechanism of response, we performed extensive tumor immuno-profiling for the presence of infiltrating immune cells, e.g. TIL, CTL, Treg, immune-suppressive macrophages, NK, etc3. We observed a good pharmacodynamic (PD) correlation between the presence of tumor infiltrating T-cells, particularly CD8+ TIL, and NK and a positive response to therapy, regardless the treatment type. Given this preliminary observation, we attempted animal vaccination with tumor lysates prior to tumor engraftment or treatments. Interestingly, while vaccination had minimal effects on the engraftment take rate (100% take for all animals) and on the growth kinetics of the engraftments, it had profound effects on the tumor response to anti-PD1/anti-PDL-1 antibody treatments, significantly enhancing tumor response to these agents in a model that was otherwise unresponsive. Our results suggest that the immunological status of the animal, at least with regard to the specific anti-tumor immunity, is critically important to determine the response to checkpoint inhibitors. Our observations suggest that vaccination is critical for the overall success of immunotherapy (I/O) treatments utilizing checkpoint inhibitors as well other treatment strategies. References 1. Guy, C.T., Cardiff, R.D. & Muller, W.J. Induction of mammary tumors by expression of polyomavirus middle T oncogene: a transgenic mouse model for metastatic disease. Molecular and cellular biology 12, 954-961 (1992). 2. Annie Xiaoyu An1, Jinping Liu1, Jie Cai1, Jean Pierre Wery1, and Henry Q.X. Li1,. Building mouse tumor derived allogragfts for immune-oncology research. (2015). 3. Zhun Wang1, A.X.A., 2*, Jinping Liu1, Gavin Jiagui Qu1, Likun Zhang, Jie Cai1, Bin Chen1, Davy Xuesong Ouyang1, Jean Pierre Wery1, and Henry Q.X. Li1,2. Response to checkpoint inhibition by GEMM breast cancer allograft EORTC-AACR-NCI Abstract (2015). Citation Format: Zhun Wang, Xiaoyu An, Jinping Liu, Xuesong Ouyang, Jiagui Qu, Likun Zhang, Jie Cai, Jean-Pierre Wery, Henry Li. Prior vaccination is critical to PD1/PDL-1 treatment efficacy in a mouse breast cancer allograft. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3219.

Patient-derived xenograft (PDX) models closely mimic the pathological phenotypes of the original tumors, thus they are ideal surrogates for preclinical anticancer drugs efficacy testing. However, there is an increasing demand to rapidly and reliably screen out candidate drugs at earlier stages, and in vivo animal studies usually take months to produce efficacy data. Compared to traditional two-dimensional (2D) culture, three-dimensional (3D) culture systems more closely reflect in vivo responses. Therefore, we developed an ex vivo 3D culture platform using freshly isolated PDX-derived tumor cells, cultured on the natural methylcellulose polymer as an ex vivo drug screening system to meet the need for patient relevant, lower cost and high-throughput methods. Single-cell suspensions freshly isolated from PDX tumors are seeded in semisolid methylcellulose media and the drug efficacy is quantitatively evaluated by CellTiter-Glo® (CTG) luminescent assay. The main advantage of this method is the possibility of testing cytotoxicity within days (7 days on average), rather than months. Also, the process is carried out in mild condition and the scaffold material is inert to avoid unwanted cellular response. Moreover, cell spheroids can be easily retrieved for further analysis. Dissociated primary tumor cells derived from either fresh or frozen PDX tumors remain highly viable and form colonies when cultured in 3D. The success rate of generating ex vivo 3D culture from PDX tumors is higher than 90%, and over 60 PDX models were validated from cancer of various origins. We monitored tumor colony formation and generated a fitted drug concentration-response curve with small variations in CTG cell viability assays. Most importantly, the ex vivo 3D drug response profiling correlated well with the response obtained in vivo from PDX models (over 80% in average), for anticancer drugs with a variety of mechanisms of action including kinase inhibitor, antineoplastic agent and antibodies. Compared with a commercialized 3D drug testing plates, similar results were obtained in our system, with the advantage of a significant reduction in the cost. These data suggest that our 3D ex vivo cell culture platform from freshly isolated or frozen PDX-derived cells is a feasible and authentic method for testing drug efficacy in a short time period before transitioning to multiple PDX models. To sum up, our ex vivo 3D culture platform can save time and reduce costs, and is extremely useful for preclinical evaluation of anticancer drug, filling the gap between cell line-based and tumor bearing mice-based drug studies, allowing low cost, high throughput in vitro drug screening and the clinically relevant in vivo drug efficacy studies. Citation Format: Xiaoxi Xu, Wenna Zhang, Bingying Xie, Zheng Zheng Bao, Zhu Mei, Jean-Pierre Wery, Jinying Ning. An established ex vivo 3D culture platform using patient-derived xenograft (PDX) tumors replicate the anti-tumor efficacy observed in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 609.

The interaction between the c-MET tyrosine kinase receptor (RTK) on the surface of cancer cells with its ligand, hepatocyte growth factor (HGF) secreted from surrounding tumor stroma, results in paracrine signal transduction in cancer cells to promote growth, invasion, angiogenesis and metastases. c-MET gene amplification/over-expression, or activating mutations, frequently function as oncogenic driver in several types of cancers. c-MET is thus considered a key target(1) for both TKIs or biologics. However, lack of suitable animal models has represented an obstacle for the development of new cMET inhibitors. While patient derived xenografts (PDXs) mirror patients’ histopathological/genetic profiles(2-6), they usually lose human stroma, the source of HGF; moreover the HGF originated from murine stroma is incapable of triggering a paracrine signaling because of lack of cross reactivity with the human c-MET. Some PDX grow independent of paracrine mechanisms because of their constitutive c-MET activation by the presence of activating mutations, gene amplification or autocrine signaling, and can be used to evaluate the efficacy of TKIs(5, 7, 8). However they are not suitable to assess biologics, e.g. antibodies disrupting receptor-ligand interaction. Alternatively it is possible to grow tumors in hu-HGF-transgenic immunocompromised mice (humanization) where an artificial paracrine signaling is created. Interestingly, we have identified a unique HCC-PDX, LI0801, which maintains human stroma throughout passages, as demonstrated by immunochemistry staining for human vimentine and human HGF, both markers of stromal components(7, 8). The mechanisms of human stroma maintenance in this PDXremain unclear. We showed that LI0801 responds to different TKIs(7, 8). In addition we evaluated the efficacy of an anti-human c-MET monoclonal antibody in reducing tumor burden in LI0801, and we were able to demonstrate great tumor response to anti-human c-MET antibody, which is significantly more effective than crizotinib. To the best of our knowledge, LI0801 is the first paracrine c-MET PDX reported, and represents an important model to study paracrine cMET/HGF signaling and to evaluate new c-MET inhibitors, both TKIs, and biologics. References 1. Comoglio PM, et al. Nat Rev Drug Discov. 2008;7:504-16. 2. Ding L, et al. Nature. 2010;464:999-1005. 3.Marangoni E, et al. A new model of patient tumor-derived breast cancer xenografts for preclinical assays. Clin Cancer Res. 2007;13:3989-98. 4.Chen D, Oncotarget. 2015. 5. Yang M, et al. International journal of cancer Journal international du cancer. 2013;132:E74-84. 6. Zhang L, et al. A subset of gastric cancers with EGFR amplification and overexpression respond to cetuximab therapy. Sci Rep. 2013;3:2992. 7. Bladt F, et al. Cancers (Basel). 2014;6:1736-52. 8. Chen D. AACR Annual Meeting 2012. 2012;Poster. Citation Format: Dawei Chen, Ziyong Sun, Likun Zhang, Jie Cai, Davy X. Ouyang, Jean-Pierre Wery, Henry Li. Paracrine c-MET/HGF HCC PDX: evaluation of a biologics targeting c-MET. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 747.

The recent clinical success of novel therapeutics blocking immune checkpoints cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) and programmed cell death 1 (PD-1) has fueled an intense interest around immuno-oncology. However, the lack of relevant animal models is a major bottleneck for understanding the mechanism of action and evaluating the efficacy of such therapeutics. Syngeneic mouse tumor models, despite being widely used as experimental models for efficacy studies, are limited by the restricted number of models available and responsive to current checkpoint inhibitors. Genetically engineered mouse models (GEMMs) of human cancer are effective tools for mechanistic analysis, but they are often not suitable for efficacy studies due to usually un-synchronized tumor progression. Syngeneic allografts of spontaneous mouse tumors derived from GEMMs (MuPrime®) may be used as a new type of immuno-oncology models with the following advantages: 1) their primary nature of “stem cell diseases” and relevant tumor microenvironment mirror the patient derived xenograft (PDX) models; 2) the availability of diverse cancer types and oncogenic drivers deriving from a wide range of GEMMs. We set out to build a library of allografts of spontaneous mouse tumors, including those derived from GEMM, in an immunocompetent host to support pharmacological investigation, particularly of immuno-oncology agents. Recently, we observed the growth of spontaneous cutaneous tumors on the neck of the C57BL/6J-ApcMin/J GEMM, which is heterozygous for the Apc (APCMin/+). Histopathology suggests the tumors are well-differentiated skin squamous cell carcinoma. We subcutaneously transplanted these skin tumors into the syngeneic C57BL/6J mice. The allografts grow well, are serially transplantable and maintain the histopathology of the primary tumor. Transcriptome sequencing revealed that the allografts maintain the original ApcMin mutation, express high levels of HER2 (also confirmed by immunochemistry, or IHC), and present frameshift mutations in both c-met and EGFR. In vivo pharmacological assessment indicate that tumors respond to 5-FU, paclitaxel, gemcitabine, docetaxel, and cisplatin chemotherapy. They is also sensitive to anti-mouse CTLA-4 antibody, and the response is associated with an increased number of tumor infiltrating immune cells, including TILs. Alltogether, here we show that we have established an allograft model suitable for in vivo efficacy analysis of immunotherapy using surrogate anti-mouse antibodies. Citation Format: Gavin Jiagui Qu, Annie Xiaoyu An, Jinping Liu, Davy Xuesong Ouyang, Likun Zhang, Jie Cai, Jean Pierre Wery, Henry Q. X. Li. Establishment of a mouse skin squamous cell carcinoma allograft model for in vivo pharmacological analysis of immunotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4043.

A lead compound obtained from a high volume human non-pancreatic secretory phospholipase A2 (hnps-PLA2) screen has been developed into a potent inhibitor using detailed structural knowledge of inhibitor binding to the enzyme active site. Four crystal structures of hnps-PLA2 complexed with a series of increasingly potent indole inhibitors were determined and used as the structural basis for both understanding this binding and providing valuable insights for further development. The application of structure-based drug design has made possible improvements in the binding of this screening lead to the enzyme by nearly three orders of magnitude. Furthermore, the optimized structure (LY311727) displayed 1,500-fold selectivity when assayed against porcine pancreatic s-PLA2.

Overall benefits of EGFR-TKIs are limited because these treatments are largely only for adenocarcinoma (ADC) with EGFR activating mutation. The treatments also usually lead to development of resistances. We have established a panel of patient-derived xenografts (PDXs) from treatment naive Asian NSCLC patients, including those containing "classic" EGFR activating mutations. Some of these EGFR-mutated PDXs do not respond to erlotinib: LU1868 containing L858R/T790M mutations, and LU0858 having L858R mutation as well as c-MET gene amplification, both squamous cell carcinoma (SCC). Treatment of LU0858 with crizotinib, a small molecule inhibitor for ALK and c-MET, inhibited tumor growth and c-MET activity. Combination of erlotinib and crizotinib caused complete response, indicating the activation of both EGFR and c-MET promote its growth/survival. LU2503 and LU1901, both with wild-type EGFR and c-MET gene amplification, showed complete response to crizotinib alone, suggesting that c-MET gene amplification, not EGFR signaling, is the main oncogenic driver. Interestingly, LU1868 with the EGFR L858R/T790M, but without c-met amplification, had a complete response to cetuximab. Our data offer novel practical approaches to overcome the two most common resistances to EGFR-TKIs seen in the clinic using marketed target therapies.

Phospholipases A2 (PLA2s) may be grouped into distinct families of proteins that catalyse the hydrolysis of the 2-acyl bond of phospholipids and perform a variety of biological functions. The best characterized are the small (relative molecular mass approximately 14,000) calcium-dependent, secretory enzymes of diverse origin, such as pancreatic and venom PLA2s. The structures and functions of several PLA2s are known. Recently, high-resolution crystal structures of complexes of secretory PLA2s with phosphonate phospholipid analogues have provided information about the detailed stereochemistry of transition-state binding, confirming the proposed catalytic mechanism of esterolysis. By contrast, studies on mammalian nonpancreatic secretory PLA2s (s-PLA2s) have only recently begun; s-PLA2s are scarce in normal cells and tissues but large amounts are found in association with local and systemic inflammatory processes and tissue injury in animals and man. Such s-PLAs have been purified from rabbit and rat inflammatory exudate, from synovial fluid from patients with rheumatoid arthritis and from human platelets. Cloning and sequencing shows that the primary structure of the human s-PLA2 has about 37% homology with that of bovine pancreatic PLA2 and 44% homology with that of Crotalus atrox PLA2. The human s-PLA2 is an unusually basic protein, yet contains most of the highly conserved amino-acid residues and sequences characteristic of the PLA2s sequenced so far. Here we report the refined, three-dimensional crystal structure at 2.2 A resolution of recombinant human rheumatoid arthritic synovial fluid PLA2. This may aid the development of potent and specific inhibitors of this enzyme using structure-based design.

Background. Activated B cell-like (ABC) is a subtype of DLBCL difficult to treat. Activation of B-cell receptor (BCR) signaling pathway, including CD79 transmembrane proteins (A/B subunits) and Bruton's tyrosine kinase (BTK), are required for the disease maintenance. The MYD88 (an adapter for Toll-like receptors in a separate pathway from BCR pathway) activating mutation, L265P, has been suggested to activate BCR pathway (29% of ABC-DLBCL) and thus drives the disease. These DLBCLs seem responsive to ibrutinib (a BTK inhibitor) in the clinics1,2. Majority of MYD88-L265P mutant DLBCL patients also have CD79B mutation (e.g. Y197N), i.e. double mutants (21% of total ABC-DLBCL), hinting collaborative oncogenesis, while some are MYD88-L265P single mutant with wild type CD79B. It remains unclear whether the single and double mutant ABC-DLBCL differ in their molecular pathogenesis as well as response to ibrutinib. Method. We created DLBCL patient derived xenografts (PDX) as experimental system mimicking patients in order to investigate the molecular pathogenesis/response to ibrutinib. We first transcriptome-sequenced the established PDXs. We categorized them into ABC/GCB subtypes along with mutation status of CD79B/MYD88 per transcriptome profiles. We then assessed these PDXs for their response to ibrutinib and trying to correlate antitumor activity to molecular signature. Results. We have created 20 NHL-PDX, with 5 of them transcriptome-sequenced. Clustering analysis per expression profile of 14-genes have classified all these 5 into subclass ABC-DLBCL. Among the 5, one is MYD88-L265P/CD79B-Y197N double mutants (LY2298), one MYD88-L265P single mutant (LY0257), and three wild types (LY2345, LY2214, LY2266). Among the 3 models tested so far, LY2214 (wildtype) and LY0257 (single mutation) did not respond to ibrutinib, but LY2298 (double mutations) did. These results, although small sample sizes, seem to suggest that double mutations are required for the response to ibrutinib, while single mutant and wild type does not. These observation seem to be consistent with the implication from recent clinical study1. We are currently profile and test the remaining models to further confirm these observations. We will also further elucidate the downstream signaling along with the drug response. Conclusion. Our preliminary results confirmed that ibrutinib sensitivity correlates with the concomitant double mutation of CD79B and MYD88. References 1. Wilson, W.H., et al. Targeting B cell receptor signaling with ibrutinib in diffuse large B cell lymphoma. Nature medicine (2015). 2. Aalipour, A. & Advani, R.H. Bruton's tyrosine kinase inhibitors and their clinical potential in the treatment of B-cell malignancies: focus on ibrutinib. Therapeutic advances in hematology5, 121-133 (2014). Disclosures No relevant conflicts of interest to declare.

Background. Cancer patient's response to immunotherapy, e.g. checkpoint inhibitors, differ greatly, likely due to their genetic composition (e.g. neo-mutation) or immunological profile of tumors. Experimental models may facilitate the identification of responders or of the approach to enhance response. Syngeneic mouse tumor models have been widely used as experimental model for testing surrogate immunotherapy, but limited by the fact that only a few are available and respond to the current checkpoint inhibitors. Allografts of mouse spontaneous tumors (MuPrimeTM) may be used as new type of I/O model with advantages: 1) its primary natures with “stem cell diseases” and relevant tumor microenvironment as seen in PDX1-5; 2) diverse cancer types and deriving from wider range of available spontaneous mouse tumors. Method. We created a MuPrime, MBR6004, by allografting the breast adenocarcinoma derived from GEMM-MMTV-PyVT in FVB/N mice1. We then characterized the model by examine it subcutaneous and orthotopic growth, and its ability to metastasis. We also transcriptome-sequenced and immune-profiled the tumor, and assessed its response to different treatments, including I/O therapy. Results. MBR6004 was found to over-express HER2 but negative for ER and PR. It maintains original primary tumour histopathology, grows robustly, and is confirmed to express its original transgene. It is also resistant to docetaxel. The orthotopic implantation resulted in lung metastasis. We can detected and quantitatively confirmed tumor-infiltrating immune cells, e.g. TIL, CTL, Treg, immune-suppression macrophage, NK, etc. We confirmed that the tumor cell expressed relatively low PD-L1, but inducible, per flow analysis. Our preliminary data indicated that it partially respond to anti-mouse PD1 and anti-mouse CTLA-4 antibodies when mice are preconditioned. Currently, we are investigating whether the responses are associated with the reduced Treg and increased CD8+ TIL in tumors, and also whether the combination therapy can enhance its tumor response synergistically. Conclusion. Our data seem to suggest that MuPrime could be another type of I/O model alternative to commonly used syngeneic cell line derived models at present. References 1. Guy, C.T., Cardiff, R.D. & Muller, W.J. Induction of mammary tumors by expression of polyomavirus middle T oncogene: a transgenic mouse model for metastatic disease. Molecular and cellular biology 12, 954-961 (1992). 2. Guy, C.T., et al. Expression of the neu protooncogene in the mammary epithelium of transgenic mice induces metastatic disease. Proc Natl Acad Sci U S A 89, 10578-10582 (1992). 3. Moser, A.R., Dove, W.F., Roth, K.A. & Gordon, J.I. The Min (multiple intestinal neoplasia) mutation: its effect on gut epithelial cell differentiation and interaction with a modifier system. The Journal of cell biology 116, 1517-1526 (1992). 4. Moser, A.R., et al. ApcMin, a mutation in the murine Apc gene, predisposes to mammary carcinomas and focal alveolar hyperplasias. Proc Natl Acad Sci U S A 90, 8977-8981 (1993). 5. Moser, A.R., Pitot, H.C. & Dove, W.F. A dominant mutation that predisposes to multiple intestinal neoplasia in the mouse. Science 247, 322-324 (1990). Citation Format: Zhun Wang, Xiaoyu An, Jinping Liu, Jie Cai, Likun Zhang, Jiagui Qu, Davy Ouyang, Bin Chen, Jean-Pierre Wery, Henry Li. Response to checkpoint inhibition by GEMM breast cancer allograft. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B97.

Background. The Cancer Genome Atlas (TCGA) and many other genomic profiling of patient samples generated abundant human cancer genomic datasets of various histological types and individual patients, enabling development of molecular pathology methodology per big data fashion1-4. Patient derived xenograft (PDX) is believed to mimic patient tumors with anecdotal data, and assumed to be predictive experimental models (avatar) for human trial. There is also a need to investigate tumor pathology among different histopathology types, either patient or xenograft diseases, per “big data” approach. Methods. We first systematically compared transcriptome expression similarity within and between specific histological types using either global or specific subsets of genes using the datasets from TCGA. We next investigated PDXs (also cell lines) using the same systemic approaches. Results. We demonstrated the presence of highly consistent correlation in transcriptome expression within a given histology types, but more distinct between the types, establishing molecular specificity alternative to histological type based on morphology, or an alternative diagnostic approach. We performed the same systematic examination of PDXs of different histological types corresponding to the TCGA types. The similar general pattern of similarity, also somewhat reduced in degree, have been observed. These suggest the high relevance of PDX to human cancer tissues in general from “big data” perspective. In contrast, this seems generally untrue for cancer cell lines: quite similar among themselves even for different histological types, but less correlation to either TCGA or PDXs per disease type. The similarity among cell lines of all types may suggest a “new type of cancer, or tissue culture type”. Our studies also revealed certain specific correlations, with several examples: 1) colon and rectal adenocarcinoma are highly correlated, without apparent difference; 2) NSCLC SCC are quite different from NSCLC ADC, as seen morphologically; 3) NSCLC SCC are also quite closely related to HNSCC. Conclusion. There are generally good correlation between transcriptome expression based molecular pathology and histopathology; the molecular pathology of PDXs are generally similar to that of human's, not so to human cell lines. References 1. Comprehensive molecular characterization of gastric adenocarcinoma. Nature 513, 202-209 (2014). 2. Hoshida, Y., et al. Integrative transcriptome analysis reveals common molecular subclasses of human hepatocellular carcinoma. Cancer research 69, 7385-7392 (2009). 3. Comprehensive genomic characterization defines human glioblastoma genes and core pathways. Nature 455, 1061-1068 (2008). 4. Ge, L., et al. Integrated analysis of gene expression profile and genetic variations associated with ovarian cancer. European review for medical and pharmacological sciences 19, 2703-2710 (2015). Citation Format: Sheng Guo, Wubin Qian, Jie Cai, Likun Zhang, Jean-Pierre Wery, Henry Li. Molecular pathology of patient derived xenografts. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B101.

Background. Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase, and its mutation, over-expression and gene fusion have been associated with various cancers. EML4-ALK fusion has been confirmed to be an oncogenic driver for a small subset of the lung cancers (∼4% of NSCLC)1, and becomes an excellent drug target that led to the development of the first effective therapy, crizotinib, a tyrosine kinase inhibitor for anaplastic lymphoma kinase, for this disease 2,3. However, like any other cancer therapy so far, the treatment always led to the development of resistance, rendering them ineffective in the end4. Understanding the mechanisms causing these resistances can potentially facilitate overcoming the resistance and extend patients' life5,6. However, lack of experimental model hinders this understanding. Method. We have recently established a large collection of patient derived xenografts (∼350 PDXs)7, and we screened some of them for alk gene fusions. We then tested the positive model for sensitivity to crizothinib, and keep it under several rounds of crizotinib treatments to select resistant model. The induced resistant model was subjected to genomic analysis to identify the changes that might potentially be responsible for the resistance. Results. We identified one model, NSCLC LU1656, containing EML4-ALK fusion with elevated ALK expression. It has also been shown to respond well to crizotinib in vivo. The continued treatment eventually led to the development of resistance to crizotinib (LU2445), a situation that might occur in patients in the clinic under the same treatment. We have performed transcriptome sequencing of the parental sensitive tumor (LU1656) and the selected resistant tumor (LU2445). So far, we found both models expressed similar high levels of expression of ALK, but no additional mutations in ALK gene. There are other alterations either genetically or epigenetically, some seemingly related to the ALK signaling pathways. However, their role in resistance still need to be confirmed. Conclusions. Induced crizotinib resistance in ALK-fusion lung PDX can be useful to investigate crizotinib resistant mechanism and future drugs overcoming the resistance. References 1. Koivunen, J.P., et al. EML4-ALK fusion gene and efficacy of an ALK kinase inhibitor in lung cancer. Clinical cancer research : an official journal of the American Association for Cancer Research 14, 4275-4283 (2008). 2. Kwak, E.L., et al. Anaplastic lymphoma kinase inhibition in non-small-cell lung cancer. N Engl J Med 363, 1693-1703 (2010). 3. Takeuchi, K., et al. RET, ROS1 and ALK fusions in lung cancer. Nature medicine 18, 378-381 (2012). 4. Katayama, R., et al. Mechanisms of acquired crizotinib resistance in ALK-rearranged lung Cancers. Science translational medicine 4, 120ra117 (2012). 5. Katayama, R., et al. Two novel ALK mutations mediate acquired resistance to the next-generation ALK inhibitor alectinib. Clinical cancer research : an official journal of the American Association for Cancer Research 20, 5686-5696 (2014). 6. Friboulet, L., et al. The ALK inhibitor ceritinib overcomes crizotinib resistance in non-small cell lung cancer. Cancer discovery 4, 662-673 (2014). 7. Yang, M., et al. Overcoming erlotinib resistance with tailored treatment regimen in patient-derived xenografts from naive Asian NSCLC patients. Int J Cancer 132, E74-84 (2013). Citation Format: Jianyun Deng, Zhun Wang, Jie Cai, Sheng Guo, Jean-Pierre Wery, Henry Li. Induction of resistances to crizotinib in lung patient derived xenograft. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C82.

Background. Blockage of immune checkpoints, e.g. by anti-PD1 antibody, becomes an important new cancer therapy1. Experimental models are important to evaluate new investigational therapy or new combination strategy. Syngeneic mouse tumor models have been widely utilized as an experimental model for testing surrogate immune-oncology (I/O) therapy by using its competent mouse immunity2, but cannot be used for testing human biologic therapeutics, due to the species specificity. The direct replacing mouse therapeutic target by human counterpart in mouse while maintaining the normal mouse immune-functions could be a potential practical preclinical approach to evaluate human biologic therapeutics in vivo. Methods. We have engineered a chimeric human/mouse PD1 gene (h/mPD1) composed of human exome 2&3 and mouse exome 1&4. We expressed the recombinant proteins and tested their bindings to their binding partner of PDL1 of both mouse and human origins, and also anti-human PD1 antibody. We knock-in the recombinant gene into C57Bl/6 mouse to create homozygous HuGEMM-h/mPD1 mouse, which is tested for growth of MC38 syngeneic mouse cell line tumor graft and for the growth inhibition by anti-human PDL1 antibody. Results. Our data demonstrated that chimeric protein h/mPD1 can interchangeably interact with mPDL1 or hPDL1 efficiently as efficiently as mouse PD1, and it also recognizes anti-human PD1 antibody as expected. The binding of anti-human PD1 antibody blocks its binding to mouse or human PDL1. The knock-in mice express the chimeric gene in the T-cells of the engineered mice both in vivo and ex vivo, however at significantly lower levels than mouse PD1 in the wild type C57BL/6 mice (1/10) under induction. When syngeneic MC38 cell line was subcutaneously engrafted in HuGEMM-h/mPD1 mice, the tumor were found to grow significantly slower with increased T-cell infiltration, as compared to those in the wild type mice. MC38 tumor did not respond to anti-human PD1 antibody well either. These observations can apparently be attributed to the low level PD1 and the associated high autoimmunity that also inhibits tumor growth. Interestingly, a specific condition can be artificially created to enhance MC38 tumor growth in the chimeric mice, likely contributed by the enhanced h/mPD1 expression. The enhanced tumor growth seems to also be suppressible, at least partially, by anti-human PD1 antibody as shown in our preliminary study. Currently, we are re-engineering our chimeric gene (version 2) in order to increase their expression to the wild type gene level, so to create a model for more optimal drug evaluation. In the meantime, we are also engineering HuGEMM-hu-CKPT (e.g. CTLA4 PDL-1, OX40, 4-1BB, etc.) for evaluating other checkpoint inhibitors. Conclusions. Our data suggests the conditioned version 1-HuGEMM-h/mPD1 mouse can be explored to evaluate anti-human antibody. References 1. Pardoll, D.M. The blockade of immune checkpoints in cancer immunotherapy. Nature reviews. Cancer 12, 252-264 (2012). 2. Allard, B., Pommey, S., Smyth, M.J. & Stagg, J. Targeting CD73 enhances the antitumor activity of anti-PD-1 and anti-CTLA-4 mAbs. Clinical cancer research : an official journal of the American Association for Cancer Research 19, 5626-5635 (2013). Citation Format: Zhun Wang, Bin Cai, GANG Chen, Jinping Liu, Xiaoyu An, Zhengsheng Wang, Davy Ouyang, Jean-Pierre Wery, Jay Liu, Xin Dong, Henry Li. HuGEMM-h/mPD1 mouse models for assessing anti-human PD1 therapeutics. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A11.

Immuno-oncology is an area under intensive investigation, however, many questions remain to be answered due to lack of sufficient number of adequate experimental models: 1) why only subsets of patients respond? 2) who will respond (signature)? 3) what can we do to make more patients to respond? Patient derived xenograft (PDX or HuPrime®) mirrors patients’ histopathological/genetic profiles, considered more predictive than traditional human cell line derived xenograft (CDX) and also syngenic mouse cell derived models, due to the primary natures of PDX. On the other hand, both xenografts (PDX/CDX) grow in absence of immunity, thus unsuitable for immune-oncology research. Limited types/numbers of available syngenic cells also restrict its application. Genetically engineered mutant mouse cancer model (GEMM) are diverse (types/numbers)1-5, grow in immune-environment, and are primary tumors. However, GEMM has logistic limitation for pharmacology research for high cost and high variations in tumor development (spontaneous) in type/time. We set out to create a library of primary mouse tumor allografts (MuPrimeTM) as standard experimental models, aiming at overcoming these limitations. We established a number of such allografts and are profiling them for growth, histopathology, genomic (RNAseq), and standard of care (SOC). We are also charactering their immune-oncology properties: tumor-infiltrating immune cells, including different subtypes of T-cells (CTL, Treg), as well as their functional activation/suppression and tumor responses to immune-modulating agents. MBR6004 is an allograft derived from a breast adenocarcinoma of GEMM-MMTV-PyVT in FVB/N mice1, which expressed medium level Her2 but negative for ER and PR, and is resistant to Docetaxel(SOC). It expresses low-level PD-L1(CD274)/L2 and seems insensitive to PD-1 antibody treatment. MCR6013, an allograft of a colon adenocarcinoma derived from GEMM-C57BL/6J-ApcMin/JNju3-5, are currently being profiled. MPR6003, an allograft of transgenic adenocarcinoma mouse prostate (TRAMP) in C57BL/6 mice6-8, grow both orthotopically and subcutaneously, and are also being profiled. M6011, an allograft derived from a spontaneous tumor in Balb/c mouse with high Her2 expression, has apparent infiltration of T-cells, including Treg, but negative for PD-L1. We are currently characterizing its histopathology and other property. MLY1014, an allograft of a spontaneous lymphoma derived from Balb/c, is also being profiled. In general, these allografts keep the original primary tumor histopathology, but distinct from conventional syngenic cell line derived tumors, a contrast seen between PDX vs. CDX. The models grow robustly after engraftment, thus ideal for pharmacology evaluation. Our ongoing studies will provide a useful platform with normal immunity for drug evaluation, particularly for immune-oncology agents. Citation Format: Xiaoyu An, Jinping Liu, Jie Cai, Jean-Pierre Wery, Henry Qixiang Li. Building mouse tumor derived allogragfts for immune-oncology research. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2281. doi:10.1158/1538-7445.AM2015-2281

The PI3K-mTOR pathway is one of the major signaling cascades that promote tumor growth and cell survival. Multiple inhibitors targeting this important axis are currently under clinical investigation for cancer treatment and some are under preclinical development. Here we examined the anti-proliferation activity of BEZ235, a PI3K and mTOR dual inhibitor, in 243 human cancer cell lines of different caner types. We identified 35 lines that are sensitive to the inhibitor with IC50 values less than 0,04uM and 57 insensitive lines with IC50 values more than 0.4uM. We compared gene expression of the two groups by Affymetrix U219 arrays. With a p-value cutoff set at 0.00001, we identified 14 genes that are differentially expressed. These genes include epithelial membrane glycoprotein EPCAM and serine threonine kinase 31 (STK31). Furthermore, the mutation status of tubulin tyrosine ligase TTL is significantly correlated with sensitivity to BEZ235. These results suggested a potential genomic signature that could be predictive of response to BEZ235 and provided information that may help selecting patients that are likely to receive clinical benefit. Citation Format: Jing Zhang, Sheng Guo, Zhengzheng Bao, Limei Shang, Xiao Wen, Jean-Pierre Wery, Jinying Ning. Cell-based screening identifies gene expression signature correlated with sensitivity to PI3K-mTOR dual inhibitor BEZ235. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1038. doi:10.1158/1538-7445.AM2015-1038

RET encodes a receptor tyrosine kinase (RTK) involved in cellular mechanisms of proliferation, migration and differentiation. RET fusions with different genes at 10q11.2 result in constitutively activation and drive tumor development in various cancers: 10-20% of sporadic papillary thyroid cancer1, spitzoid neoplasms, CMML and 1% of lung adenocarcinomas2,3. RET fusions have been suggested to be important therapeutic targets. Ponatinib, a multi-kinase inhibitor, was approved for the treatment of Ph+ chronic myeloid leukemia (CML) and acute lymphoblast leukemia (ALL), including CML with T315I/imatinib-resistance. Ponatinib has recently been found to potently inhibit the common NSCLC fusion variant, KIF5B-RET at clinically-achievable concentrations. We have established large collection of colorectal patient derived xenografts (PDXs)4,5. Two of the poorly differentiated adenocarcinoma, CR1520 and CR2518, contain two different chromosome 10 in-frame RET-fusions, CCDC6-RET (CR2518) and NCOA4-RET (CR1520), as revealed by RNAseq and Sanger Sequencing6. Both models have also demonstrated over-expressing ret gene at mRNA levels. More importantly, they both responded Ponatinib significantly along with dephosphorylation of RET and downstream AKT, confirming these two types of Ret fusions as oncogenic drivers in these two models6. In addition, we also observed that Ponatinib treatment also rapidly drives CR2518 into its resistance (The resistant derivative is called CR2545). To investigate the underlying mechanism of the resistance, we performed RNAseq analysis of CR2545, which revealed retaining of the ret-fusion, but also the introduction of a previously described gate-keeper mutation, V804M, at ret kinase domain. V804M, a mutation frequently found in familial medullary thyroid carcinoma (FMTC), introduces bulky amino acid at position 804 and found to resistant to vandetanib. This may contribute to the resistance. However, this notion apparently contradicts to the previous observation/claim that V804M is sensitive to Ponatinib7, and ponatinib should be used to treat RET-V804M/L cancers. It is possible that the described V804M containing vandetanib resistant cells are sensitive to ponatinib, but via a non-RET mechanism for the multi-kinase inhibition nature of ponatinib; or in our case, there are other non-RET Ponatinib resistant mechanisms been introduced in CR2545 where RET is no longer the key oncogenic driver. We are currently testing other RET inhibitors and also assessing pharmacodanamic (PD) parameters to further investigate RET resistant mechanism. The further findings from the ongoing studies will be presented at the meeting. Citation Format: Mengmeng Yang, Jie Cai, Sheng Guo, Jean-Pierre Wery, Henry Qixiang Li. Rapid conversion to resistance, of a colon PDX with ret-fusion, by ponatinib treatment could potentially be attributed to the introduction of the gate keeper mutation V804M. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3581. doi:10.1158/1538-7445.AM2015-3581

Patient derived xenografts (PDXs) mirrors patients’ pathology and genetic profiles, thus valued as predictive experimental models for studying oncogenesis and personalized treatments. Cancer is not a single disease but diseases of complex genetic components and oncogenic processes. Limited number of PDX models with minimal genetic characterization is insufficient to meet current research needs. For this, we have built the largest and most comprehensive PDX library with full genetic profiles. By far, our PDX library contains over 1,100 models derived from patients of both Asian and Western origins, covering over 20 major cancer types, including large panels (over 100 models each) of NSLCL(1), CRC(2), gastric(3), HCC(4), and pancreatic, and smaller panels ( Our large library of different disease panels are particularly useful in conducting mouse clinical trial (MCT of HuTrialTM) (2, 5, 12), which can be used to discover predictive biomarker (2, 5, 13) and guide clinical study design. Citation Format: Jie Cai, Dawei Chen, Rajendra Kumari, Sheng Guo, Jie Yang, Mengmeng Yang, Andrew McKenzie, Zhun Wang, Xuesong Huang, Xiaoyu An, Jinping Liu, Jean-Pierre Wery, Henry Li. Building comprehensive and fully annotated patient tumor derived xenogragft (PDX) library mirroring cancer patient population. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1472. doi:10.1158/1538-7445.AM2015-1472

Patient derived xenografts (PDXs) without in vitro manipulation are believed to mirror original patients’ histopathologic and genetic profiles, thus to be predictive surrogate models for patients, with superiority over conventional cell lines. We have built the largest and comprehensive PDX library of >1,100 models with genetic profiles of major cancer types, including some major cancer types: 200 NSLCL1, 200 CRC2, 200 gastric3, 100 HCC4, 100 pancreatic, 30 ovarian, 10 brain tumors, and many other cancer types. We set out to compare these 6 types of our PDXs with the corresponding TCGA5 patient tumor samples and CCLE6 cancer cell lines on their genomic expression by calculating pairwise Spearman rank correlation coefficient ρ, in order to further explore/confirm the similarity and difference among the three collections. PDX were profiled by both RNAseq and microarray (Affymetrix Human Genome U219 Array); CCLE were from microarray (Affymetrix Human Genome U133 Plus 2.0 Array); and TCGA were from RNAseq. For convenience, these 4 gene expression datasets are called “PDX, PDXchip, CCLE and TCGA”. Only genes common to all 4 datasets were used to compute ρ. The preliminary data seems to lead to two observations. First, for all 6 types, there is always at least one different tumor CCLE-TCGA pair that has higher ρ than the same tumor CCLE-TCGA pair. For example, the TCGA colorectal, lung, and ovarian cancers have higher ρ with CCLE pancreatic cancer than the TCGA pancreatic cancer does. In contrast, for both PDX and PDXchip, only lung and pancreatic cancers show such behavior, and notable, both to TCGA colorectal cancer. Seocnd, for same tumor type comparisons, ρ is 0.73-0.83 (average 0.772) between PDX and TCGA, 0.67-0.76 (average 0.698) between PDXchip and TCGA, 0.67-0.7 (average 0.682) between CCLE and TCGA. Third, about 20% of CCLE lung cancers have much lower ρ with TCGA, PDX, and PDXchip lung cancers than the other CCLE lung cancers. In summary, these observations show that our PDX models are close in genomic expression profile to TCGA patient tumors per tumor types specifically, and more so than CCLE cancer cell lines, which is also less specific. References 1. Yang, M., et al. Overcoming erlotinib resistance with tailored treatment regimen in patient-derived xenografts from naive Asian NSCLC patients. Int J Cancer 132, E74-84 (2013). 2. Chen, D. Cetuximab response in CRC patient-derived xenografts is predicted by RAS pathway activation rather than KRAS mutation status. ASCO 2013 Annual Conference (2013). 3. Zhang, J. et al. A more efficient RNAi inducible system for tight regulation of gene expression in mammalian cells and xenograft animals. Rna 13, 1375-1383 (2007). 4. Guo, S. et al AACR-Annual Conference (2013). 5. http://cancergenome.nih.gov/. 6. Barretina J, et al. http://www.broadinstitute.org/ccle/home. Nature 28, 603-607 (2012). Citation Format: Sheng Guo, Wubin Qian, Jie Cai, Jean-Pierre Wery, Henry Qixiang Li. Patient-derived xenografts seem to have closer global expression profile to that of the patient tumors of the corresponding cancer types, than the equivalent cell lines do. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1926. doi:10.1158/1538-7445.AM2015-1926

e15078 Background: Esophageal squamous cell carcinoma (ESCC) is a deadly malignance prevalent in parts of China and no target therapy option. Cetuximab, approved for treating subset of metastatic c...

e18505 Background: Patient-derived xenograft (PDX) is increasingly used to evaluate oncology drugs. PDX, reflective of original patient pathology and genomics, is predictive of response to treatmen...