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Purpose: M-protein is a well-established biomarker used for multiple myeloma monitoring. Current improvements in multiple myeloma treatment created the need to monitor minimal residual disease (MRD) with high sensitivity. Measuring residual levels of M-protein in serum by MS was established as a sensitive assay for disease monitoring. In this study we evaluated the performance of EasyM—a noninvasive, sensitive, MS-based assay for M-protein monitoring. Experimental Design: Twenty-six patients enrolled in MCRN-001 clinical trial of two high-dose alkylating agents as conditioning followed by lenalidomide maintenance were selected for the study. All selected patients achieved complete responses (CR) during treatment, whereas five experienced progressive disease on study. The M-protein of each patient was first sequenced from the diagnostic serum using our de novo protein sequencing platform. The patient-specific M-protein peptides were then measured by targeted MS assay to monitor the response to treatment. Results: The M-protein doubling over 6 months measured by EasyM could predict the relapse in 4 of 5 relapsed patients 2 to 11 months earlier than conventional testing. In 21 disease-free patients, the M-protein was still detectable by EasyM despite normal FLC and MRD negativity. Importantly, of 72 MRD negative samples with CR status, 62 were positive by EasyM. The best sensitivity achieved by EasyM, detecting 0.58 mg/L of M-protein, was 1,000- and 200-fold higher compared with serum protein electrophoresis and immunofixation electrophoresis, respectively. Conclusions: EasyM was demonstrated to be a noninvasive, sensitive assay with superior performance compared with other assays, making it ideal for multiple myeloma monitoring and relapse prediction.

Purpose: Neuroblastoma (NB) is an aggressive tumor of the developing peripheral nervous system that remains difficult to cure in the advanced stages. The poor prognosis for high-risk NB patients is associated with common disease recurrences that fail to respond to available therapies. NB tumor-initiating cells (TICs), isolated from metastases and primary tumors, may escape treatment and contribute to tumor relapse. New therapies that target the TICs may therefore prevent or treat tumor recurrences. Experimental Design: We undertook a system-level characterization of NB TICs to identify potential drug targets against recurrent NB. We used next-generation RNA sequencing and/or human exon arrays to profile the transcriptomes of 11 NB TIC lines from six NB patients, revealing genes that are highly expressed in the TICs compared with normal neural crest-like cells and unrelated cancer tissues. We used gel-free two-dimensional liquid chromatography coupled to shotgun tandem mass spectrometry to confirm the presence of proteins corresponding to the most abundant TIC-enriched transcripts, thereby providing validation to the gene expression result. Results: Our study revealed that genes in the BRCA1 signaling pathway are frequently misexpressed in NB TICs and implicated Aurora B kinase as a potential drug target for NB therapy. Treatment with a selective AURKB inhibitor was cytotoxic to NB TICs but not to the normal neural crest-like cells. Conclusion: This work provides the first high-resolution system-level analysis of the transcriptomes of 11 primary human NB TICs and identifies a set of candidate NB TIC-enriched transcripts for further development as therapeutic targets. Clin Cancer Res; 16(18); 4572–82. ©2010 AACR.

Organ transplant recipients have an increased risk of non-melanoma skin cancer (NMSC) development. Immunosuppressive agents, given to these patients to prevent organ rejection, are widely recognized to play a key role in the increased incidence of malignancy. However, different immunosuppressive agents, such as rapamycin and tacrolimus, which both prevent organ rejection, convey different risks of tumor formation. Using a UV-induced murine model of squamous cell carcinoma (SCC); HPV38 E6E7, we aim to determine whether these discrepancies are due to differences in the mechanism of immune suppression, in contrast to the much discussed direct effects of these drugs on tumor cells (i.e. immune-independent). Using customized rapamycin- and tacrolimus-incorporated feed to allow long-term administration, clinically relevant whole blood drug concentrations were obtained and validated using LC-MS/MS. Both systemic and local immunosuppression was functionally determined via adoptively transferred transgenic T-cell assay and skin allograft rejection profile, respectively. Notably however, preliminary data suggests phenotypic and functional differences of skin-residing T-cell subpopulations may exist when mice are treated with either rapamycin or tacrolimus, alluding to their potential role in the pathogenesis of NMSC. Short-term contact hypersensitivity responses (CHS) to OVA were abrogated in both rapamycin and tacrolimus-treated mice. However, prolonging the challenge phase enhanced the long-term CHS response in rapamycin-treated but not in tacrolimus-treated mice compared to normal feed controls. This enhanced response was correlated with an increased number of effector memory CD8+ T-cell population in the challenged ear skin. Using established chronic UV dosing schedules for SCC development in HPV38 E6E7 mice, tumor samples along with surrounding UV-exposed skin and fur-covered UV-protected skin samples were analyzed with FACs under the influence of these drugs. Preliminary data suggests that the formation of resident-memory CD8+ T-cells may be favored when treated with rapamycin, as higher percentages of CD8+ T-cells were present in the lesions of rapamycin-treated mice compared to tacrolimus and controls. In addition, LC-MS/MS analysis indicated that the concentration of rapamycin in the skin was significantly lower when compared to tacrolimus, whilst clinically relevant immunosuppressive concentrations of both drugs were maintained in the blood and kidneys. Through this project, we will expand our knowledge base regarding mechanisms of SCC formation in immunosuppressed patients. Citation Format: Ji-Won Jung, Paul J. Taylor, Fiona Simpson, Ian H. Frazer, James W. Wells. The impact of rapamycin and tacrolimus treatment on resident CD8+ T-cell populations in cutaneous squamous cell carcinoma. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B055.

Lung cancer is one of the most common cancers worldwide, and is the number one cause of cancer death in both men and women. Non-small cell lung cancer (NSCLC) accounts for 85% of lung cancers and is subdivided into two major histological subtypes: adenocarcinoma (ADC) and squamous cell carcinoma (SCC). There is an unmet need to better understand and stratify NSCLC according to distinctive molecular features that may help develop diagnostic and therapeutic strategies to improve patient outcomes. The proteome is expected to have a pronounced and direct effect on cancer phenotypes. Therefore, proteomic approaches hold promise as superior methods to characterize cancers, with the ultimate goal to translate research results into clinical utilities. Mass spectrometry (MS)-based quantitative comprehensive proteome analysis resolved the proteomes of human lung ADC and SCC primary tumor-derived xenografts. A multi-protein signature able to distinguish between ADC and SCC was identified and validated in an independent cohort of samples. The signature is comprised of various components of the epithelial barrier and metabolism enzymes. Signatures composed of metabolism proteins were found to be highly recapitulated between primary and matched xenograft tumors, and when extrapolated to DNA alterations in the encoding genes, to have prognostic impact for overall patient survival. The ability of NSCLC primary tumors to engraft in severely immune deficient mice is an independent predictor of shorter disease-free survival in early-stage NSCLC patients. Therefore, we sought to identify proteome signatures of engraftment, which would then be tested for prognostic impact. The proteomes of a series of >50 NSCLC primary tumors that engrafted or not were quantitatively compared by using the so-called super-SILAC method, in which a mixture of metabolically-labeled, stable-isotope-encoded NSCLC-derived cell lines were used as an internal standard. ADC and SCC tumors were analyzed, and a signature of proteins including enzymes involved in central carbon metabolism were identified as differentially expressed between engrafting and non-engrafting tumors. These results highlight the significance of metabolic remodeling as a feature that might be a determinant of more aggressive cancer phenotypes. These results support the further development of proteome signatures to diagnose, stratify, and precisely treat NSCLC. Citation Format: Wen Zhang, Paul Taylor, Lei Li, Yuhong Wei, Jiefei Tong, Vladimir Ignatchenko, Nhu-An Pham, Thomas Kislinger, Ming-sound Tsao, Michael Moran. Proteome signatures distinguish lung cancer subtypes, define metabolism states, and have prognostic impact. [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 1822. doi:10.1158/1538-7445.AM2015-1822

Non-small cell lung carcinoma (NSCLC) is a major, lethal cancer worldwide. Various molecular and cellular abnormalities are found in NSCLC, and an established theme is the alteration of protein phosphotyrosine (pY), as exemplified by elevated epidermal growth factor receptor (EGFR) activity recognized in a subset of NSCLC. In order to gain a broad perspective of pY-mediated signaling networks in NSCLC, mass spectrometry was used to analyze pY-containing peptides affinity purified from protease-digested xenograft tumors. Seventeen tumors representing the major NSCLC subtypes adenocarcinoma (ADC) and squamous cell carcinoma (SCC) were characterized. The major classes of pY proteins detected were cytoskeletal, protein kinases, and adhesion proteins. Pathways and cellular functions enriched in the data set included focal adhesion, adherens junction, and ErbB signaling. Five receptor tyrosine kinases (RTKs) were detected, with EGFR and EPHA2 most prevalent. Src-family kinases (YES, LYN, FRK and LCK) and focal adhesion kinase (FAK) comprised the majority of non-receptor tyrosine kinases measured. Analysis of individual pY sites on 14 tyrosine kinases indicates their activation by kinase domain activation loop phosphorylation, but also revealed additional pY sites suggestive of regulation by trafficking/endocytosis and inter- and intra-molecular protein-protein interactions involving, for example, SH2 and SH3 domains, and extra-kinase domain regions. Analysis of tumors based on protein-pY suggested subtypes distinguished by their activated tyrosine kinase networks. Genetic analysis of 3 tumors that displayed EGFR-associated phospho-proteome signatures confirmed that they carried either EGFR activating mutations (in two ADCs) or increased gene copy number (in one SCC). Western blot analysis of protein pY confirmed different patterns of cellular protein pY among the tumor phospho-types in agreement with the phospho-proteomic analysis. Quantification of kinase and substrate pY sites, according to their integrated extracted ion currents, revealed a set of phosphorylations that constituted a molecular signature that differentiated between the ADC and SCC subtypes. In summary, quantitative phospho-proteomic profiling of NSCLC tumors is feasible and may have utility in the categorization of individual tumors according to their networks of activated tyrosine kinases and substrates. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4805. doi:1538-7445.AM2012-4805

The epidermal growth factor receptor (EGFR) is a drug target for both small molecule and antibody therapeutics and has been approved in non small-cell lung carcinoma (NSCLC) and colorectal carcinoma (CRC) among other indications. These drugs block receptor signaling though blockade of the tyrosine kinase domain, or through inhibition of ligand binding. Current genomic tests measure receptor amplification, RNA levels, the mutation status of receptor or pathway molecules (EGFR or kRAS mutations) but no current assay can directly assess the activation state of the EGFR or its downstream signaling pathway components. Indeed, the EGFR mutation positive NSCLC tumors (thought to be constitutively active) show a high response rate to TKI therapy, but the many non responders (50% or more) demonstrate the limitation of genomic analysis. Since activation of EGFR is necessary for the response to these targeted agents, it is critical to measure what levels of receptor activation and downstream signaling determines tumor responsiveness to EGFR targeted therapies in these patients. For this reason, we have developed a panel of new diagnostic assays which measure the activation of the EGFR and key downstream signaling proteins through quantitation of the phosphorylation state of these proteins. These assays are based on the Liquid Tissue®-SRM technology platform. This approach enables relative and absolute quantification of proteins and their phosphorylation status directly in formalin fixed paraffin embedded (FFPE) tissue. We preclinically validated the multiplexed Liquid Tissue® phospho-SRM assay on formalin fixed EGF stimulated A431 cells. We followed up these in vitro studies with phospho-SRM analysis of FFPE NSCLC xenograft explants where extensive independent histopathologic and molecular characterization had been performed, allowing us to benchmark our phospho-SRM analysis with standard diagnostic analyses. We have now extended these quantitation studies by measuring the expression of EGFR and phospho-EGFR in FFPE tissues obtained from relevant human clinical trial cohorts – Gefitinib treated NSCLC and Cetuximab treated CRC. It is hoped that we will be able to correlate EGFR expression, activation and signaling in these tumors with responsiveness to EGFR targeted therapy, and to validate this assay for use as a companion diagnostic to guide therapy in both NSCLC and CRC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4919. doi:10.1158/1538-7445.AM2011-4919

Lung cancer is the leading cause of cancer death worldwide. Non-small cell lung carcinoma (NSCLC) accounts for 80% of lung cancers. The most prevalent subtypes of NSCLC are adenocarcinoma (ADC) and squamous cell carcinoma (SCC), which combined account for approximately 90%. Ten resected NSCLC patient tumors (5 ADC and 5 SCC) were directly introduced into severely immune deficient (NOD-SCID) mice, and the resulting xenograft tumors (XT) were analyzed by standard histology and immunohistochemistry (IHC) and by proteomics profiling. Mass spectrometry (MS) methods involving 1- and 2-dimensional LC-MS/MS, and multiplexed selective reaction monitoring (mSRM, or MRM), were applied to identify and quantify the xenograft proteomes. Hierarchical clustering of protein profiles distinguished between the ADC and SCC subtypes. The differential expression of >175 proteins was found to constitute a distinctive proteomic signature associated with NSCLC subtype, and an mSRM method was developed that provided relative quantification of a subset of highly differentially expressed proteins (i.e. >10-fold; p Expression Pathology Inc. 9620 Medical Center Dr. Rockville, MD 20850 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5097. doi:10.1158/1538-7445.AM2011-5097

Background: Colorectal cancer (CRC) is the second leading cause of death from cancer overall. Mutations in the K-ras oncogene are the most frequently observed mutations in CRC. Activation of receptor tyrosine kinases, including Met, is also common in CRC. Co-activation of both Met and K-Ras could result in preferential over-activation of specific downstream cascade(s). To address the potential importance of Met and K-Ras tandem activation, we use the DLD1 CRC cell line model. DLD1 cells contain one mutated K-ras allele, resulting in a constitutively active protein. These cells express a relatively low level of Met. A derivative of this cell line, DKO4, has its mutant K-ras allele inactivated by somatic recombination. Our lab has previously shown that overexpression of Met in DLD1 cells (DLD1-Met) enhances the tumorigenicity and metastatic potential of these cells. This did not occur in DKO4-Met cells, suggesting that activated K-Ras is necessary for these Met-mediated processes. We hypothesize that Met and K-Ras co-operate to activate novel tumourigenic and metastatic signaling pathways. Methods: We undertook a label-free mass spectrometry (MS)-based proteomics examination of protein-phosphotyrosine (pY) in the DLD1 CRC model. DLD1-Met and DKO4-Met cells were enriched for pY-containing peptides and then analyzed by LC-MS/MS using an LTQ-Orbitrap mass spectrometer. Peptide quantification was achieved by using both peptide ion spectral counting and normalized extracted ion current methods. To determine ligand-dependent vs. -independent differences in Met signaling, the parental DLD1 and DKO4 cells were stimulated with an HGF time course. Previous results in the lab show that DLD1 cells with activated K-Ras have prolonged MAPK signaling in response to HGF compared to DKO4 cells. Results: 9 proteins were found to be differentially regulated in these DLD1-Met vs. DKO4-Met. Validation by Western blotting in the empty vector and Met-overexpressing lines confirmed MS findings, as well as uncovered some pY changes mediated by both Met and K-Ras. Results from temporal analyses of pY in response to HGF stimulation will be presented to address this occurrence and suggest mechanisms of Met and K-Ras dependent tumourigenesis. Conclusions: We have identified a phosphoproteomic network associated with Met/K-Ras signaling. It may include novel therapeutic targets or prognostic markers for CRC. Supported by the CIHR MOP-64345 and the CIHR Banting and Best Doctoral Research Graduate Scholarship to SO Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5566.