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Supplemental Figure 1. Verification of PEDF knockdown Supplemental Figure 2. Verification of PEDF silencing in fibroblasts Supplemental Figure 3. The effect of PEDF expression in fibroblasts on tumor growth Supplemental Figure 4. The effect of endogenous PEDF on fibroblast proliferation and recruitment Supplemental Figure 5. The effect of exogenous TGFb and PDGF on PEDF mRNA in fibroblasts Supplemental Figure 6. The contribution of of TGFb and PDGF to PEDF repression assessed by shRNA silencing Supplemental Figure 7. The effect of TGFb on PDGFR mRNA levels Supplemental Figure 8. Regulation of PDGFB mRNA by TGFb Supplemental Figure 9. The role of PI3K in PEDF control by PDGF-BB Supplemental Figure 10. Inhibition of non-canonical TGFb signaling by PEDF Supplemental Figure 11. Altered expression of select genes in PEDF-null fibroblasts

PDF file - 797K, Figure S1. Barrier phenotype of human brain microvascular endothelial cells and astrocytes in monocultures and co-cultures. Figure S2. alpha/beta-crystallin does not affect cell viability of TNBC cells in standard monolayer culture. Figure S3. alpha/beta-crystallin overexpression increases liver metastases in an orthotopic model of TNBC. Figure S4. Silencing alpha/beta-crystallin inhibits liver metastases in an orthotopic model of TNBC. Figure S5. alpha/beta-crystallin does not affect proliferation or apoptosis in primary mammary tumors and brain metastatic lesions determined at autopsy. Table S1. Patient characteristics Table S2. alpha/beta-crystallin expression in paired tumors. Table S3. Association of alpha/beta-crystallin expression with breast cancer subtype. Table S4. Incidence of metastases in mice in orthotopic models of TNBC .

Supplemental Figure Legends

Loss of pigment epithelium-derived factor (PEDF, SERPINF1) in cancer cells is associated with poor prognosis and metastasis, but the contribution of stromal PEDF to cancer evolution is poorly understood. Therefore, we investigated the role of fibroblast-derived PEDF in melanoma progression. We demonstrate that normal dermal fibroblasts expressing high PEDF levels attenuated melanoma growth and angiogenesis in vivo, whereas PEDF-depleted fibroblasts exerted tumor-promoting effects. Accordingly, mice with global PEDF knockout were more susceptible to melanoma metastasis. We also demonstrate that normal fibroblasts in close contact with PEDF-null melanoma cells lost PEDF expression and tumor-suppressive properties. Further mechanistic investigations underlying the crosstalk between tumor and stromal cells revealed that melanoma cells produced PDGF-BB and TGFβ, which blocked PEDF production in fibroblasts. Notably, cancer-associated fibroblasts (CAF) isolated from patient-derived tumors expressed markedly low levels of PEDF. Treatment of patient CAF and TGFβ-treated normal fibroblasts with exogenous PEDF decreased the expression of CAF markers and restored PEDF expression. Finally, expression profiling of PEDF-depleted fibroblasts revealed induction of IL8, SERPINB2, hyaluronan synthase-2, and other genes associated with tumor promotion and metastasis. Collectively, our results demonstrate that PEDF maintains tumor-suppressive functions in fibroblasts to prevent CAF conversion and illustrate the mechanisms by which melanoma cells silence stromal PEDF to promote malignancy. Cancer Res; 76(8); 2265–76. ©2016 AACR.

Purpose:Response to toxicity in chemotherapies varies considerably from tissue to tissue and from patient to patient. An ability to monitor the tissue damage done by chemotherapy may have a profound impact on treatment and prognosis allowing for a proactive management in understanding and mitigating such events. For the first time, we investigated the feasibility of using whole-body imaging to map chemotherapeutic drug–induced toxicity on an individual basis.Experimental Design:In a preclinical proof-of-concept, rats were treated with a single clinical dose of cyclophosphamide, methotrexate, or cisplatin. In vivo whole-body imaging data were acquired using 99mTc-duramycin, which identifies dead and dying cells as an unambiguous marker for tissue injury in susceptible organs. Imaging results were cross-validated using quantitative ex vivo measurements and histopathology and compared with standard blood and serum panels for toxicology.Results:The in vivo whole-body imaging data detected widespread changes, where spatially heterogeneous toxic effects were identified across different tissues, within substructures of organs, as well as among different individuals. The signal changes were consistent with established toxicity profiles of these chemotherapeutic drugs. Apart from generating a map of susceptible tissues, this in vivo imaging approach was more sensitive compared with conventional blood and serum markers used in toxicology. Also, repeated imaging during the acute period after drug treatment captured different kinetics of tissue injury among susceptible organs in males and females.Conclusions:This novel and highly translational imaging approach shows promise in optimizing therapeutic decisions by detecting and managing drug toxicity on a personalized basis.Toxicity to normal tissues is a significant limitation in chemotherapies. This work demonstrated an in vivo imaging-based approach for characterizing toxicity-induced tissue injury in a systemic, dynamic, and near-real time fashion. This novel approach shows promise in optimizing therapeutic decisions by monitoring drug toxicity on a personalized basis.

Purpose: Basal-like breast tumors are typically (ER/PR/HER2) triple-negative and are associated with a high incidence of brain metastases and poor clinical outcomes. The molecular chaperone αB-crystallin is predominantly expressed in triple-negative breast cancer (TNBC) and contributes to an aggressive tumor phenotype in preclinical models. We investigated the potential role of αB-crystallin in brain metastasis in TNBCs.Experimental Design: αB-crystallin expression in primary breast carcinomas and brain metastases was analyzed by immunohistochemistry among patients with breast cancer with brain metastases. αB-crystallin was overexpressed or silenced in two different TNBC cell lines. The effects on cell adhesion to human brain microvascular endothelial cells (HBMEC) or extracellular matrix proteins, transendothelial migration, and transmigration across a HBMEC/astrocyte coculture blood–brain barrier (BBB) model were examined. In addition, the effects of overexpressing or silencing αB-crystallin on brain metastasis in vivo were investigated using orthotopic TNBC models.Results: In a cohort of women with breast cancer brain metastasis, αB-crystallin expression in primary breast carcinomas was associated with poor overall survival and poor survival after brain metastasis, even among patients with TNBC. Stable overexpression of αB-crystallin in TNBC cells enhanced adhesion to HBMECs, transendothelial migration, and BBB transmigration in vitro, whereas silencing αB-crystallin inhibited these events. αB-crystallin promoted adhesion of TNBC cells to HBMECs, at least in part, through an α3β1 integrin–dependent mechanism. αB-crystallin overexpression promoted brain metastasis, whereas silencing αB-crystallin inhibited brain metastasis in orthotopic TNBC models.Conclusion: αB-crystallin is a novel regulator of brain metastasis in TNBC and represents a potential biomarker and drug target for this aggressive disease. Clin Cancer Res; 20(1); 56–67. ©2013 AACR.

Supplemental Figure 1. Immunohistochemical staining of GSK-3β in low (A-C) and high (D-F) grade urothelial tumors. Supplemental Figure 2. Hoechst staining of T24 cancer cells treated with 3 distinct small molecule inhibitors of GSK-3 (AR-A014418, SB-415286, and TDZD-8). The arrows point at apoptotic cells. The percentage of apoptotic cells is shown as indicated on each picture. Supplemental Figure 3. HT1376 and T24 cancer cells were treated with indicated doses of AR-A014418; 48, 72 and 96 h after treatment, cell lysates were separated by SDS-PAGE, transferred to PVDF membrane and probed with antibodies to indicated proteins.

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supplementary Tables

V-domain Ig suppressor of T-cell activation (VISTA) is a B7 family member that plays key roles in maintaining T cell quiescence and regulation of myeloid cell populations, which together establish it as a novel immunotherapy target for solid tumors. Here we review the growing literature on VISTA expression in relation to various malignancies to better understand the role of VISTA and its interactions with both tumor cells and immune cells expressing other checkpoint molecules within the tumor microenvironment (TME). The biology of VISTA creates several mechanisms to maintain the TME, including supporting the function of myeloid-derived suppressor cells, regulating natural killer cell activation, supporting the survival of regulatory T cells, limiting antigen presentation on antigen-presenting cells and maintaining T cells in a quiescent state. Understanding these mechanisms is an important foundation of rational patient selection for anti-VISTA therapy. We provide a general framework to describe distinct patterns of VISTA expression in correlation with other known predictive immunotherapy biomarkers (programmed cell death ligand 1 and tumor-infiltrating lymphocytes) across solid tumors to facilitate investigation of the most efficacious TMEs for VISTA-targeted treatment as a single agent and/or in combination with anti-programmed death 1/anti-cytotoxic T lymphocyte antigen-4 therapies.

The selection of effective therapeutic agents is critical for improving the survival of patients with renal cell carcinoma (RCC). The aim of the present study was to develop an ex vivo drug testing assay using patient-derived tumor organoid (TO) cultures. For this purpose, surgical tumor specimens were obtained from 20 patients with RCC. TOs were developed ex vivo from freshly resected RCC tumors, and their histopathological and molecular characteristics were evaluated using histological staining and whole-exome sequencing (WES). Using a cell viability assay, the therapeutic efficacy of standard of care tyrosine kinase inhibitors in RCC TOs was determined. It was found that TOs recapitulated the histological features of primary RCC tumors. Using WES, a strong concordance was identified at the genetic level between the primary tumors and their corresponding TOs. Using patient-derived TO models, a prototype of an ex vivo drug testing assay was developed, and it was found that RCC TOs exhibited differential responses to sunitinib, pazopanib, cabozantinib, axitinib and sorafenib treatment. On the whole, although the predictive value of the current assay has to be tested and validated in future clinical studies, the findings of the present study demonstrate a novel approach for ex vivo drug testing in patient-derived TO models, which may have potential for use in the personalized treatment of cancer patients.

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is a predominantly fatal common malignancy with inadequate treatment options. Glycogen synthase kinase 3β (GSK-3β) is an emerging target in human malignancies including PDAC. Experimental Design: Pancreatic cancer cell lines and patient-derived xenografts were treated with a novel GSK-3 inhibitor 9-ING-41 alone or in combination with chemotherapy. Activation of the DNA damage response pathway and S-phase arrest induced by gemcitabine were assessed in pancreatic tumor cells with pharmacologic inhibition or siRNA depletion of GSK-3 kinases by immunoblotting, flow cytometry, and immunofluorescence. Results: 9-ING-41 treatment significantly increased pancreatic tumor cell killing when combined with chemotherapy. Inhibition of GSK-3 by 9-ING-41 prevented gemcitabine-induced S-phase arrest suggesting an impact on the ATR-mediated DNA damage response. Both 9-ING-41 and siRNA depletion of GSK-3 kinases impaired the activation of ATR leading to the phosphorylation and activation of Chk1. Mechanistically, depletion or knockdown of GSK-3 kinases resulted in the degradation of the ATR-interacting protein TopBP1, thus limiting the activation of ATR in response to single-strand DNA damage. Conclusions: These data identify a previously unknown role for GSK-3 kinases in the regulation of the TopBP1/ATR/Chk1 DNA damage response pathway. The data also support the inclusion of patients with PDAC in clinical studies of 9-ING-41 alone and in combination with gemcitabine.

Purpose: Response to toxicity in chemotherapies varies considerably from tissue to tissue and from patient to patient. An ability to monitor the tissue damage done by chemotherapy may have a profound impact on treatment and prognosis allowing for a proactive management in understanding and mitigating such events. For the first time, we investigated the feasibility of using whole-body imaging to map chemotherapeutic drug–induced toxicity on an individual basis. Experimental Design: In a preclinical proof-of-concept, rats were treated with a single clinical dose of cyclophosphamide, methotrexate, or cisplatin. In vivo whole-body imaging data were acquired using 99mTc-duramycin, which identifies dead and dying cells as an unambiguous marker for tissue injury in susceptible organs. Imaging results were cross-validated using quantitative ex vivo measurements and histopathology and compared with standard blood and serum panels for toxicology. Results: The in vivo whole-body imaging data detected widespread changes, where spatially heterogeneous toxic effects were identified across different tissues, within substructures of organs, as well as among different individuals. The signal changes were consistent with established toxicity profiles of these chemotherapeutic drugs. Apart from generating a map of susceptible tissues, this in vivo imaging approach was more sensitive compared with conventional blood and serum markers used in toxicology. Also, repeated imaging during the acute period after drug treatment captured different kinetics of tissue injury among susceptible organs in males and females. Conclusions: This novel and highly translational imaging approach shows promise in optimizing therapeutic decisions by detecting and managing drug toxicity on a personalized basis. Toxicity to normal tissues is a significant limitation in chemotherapies. This work demonstrated an in vivo imaging-based approach for characterizing toxicity-induced tissue injury in a systemic, dynamic, and near-real time fashion. This novel approach shows promise in optimizing therapeutic decisions by monitoring drug toxicity on a personalized basis.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) is a predominantly fatal common malignancy with inadequate treatment options. Glycogen synthase kinase 3β (GSK-3β) is an emerging target in human malignancies including PDAC. EXPERIMENTAL DESIGN: Pancreatic cancer cell lines and patient-derived xenografts were treated with a novel GSK-3 inhibitor 9-ING-41 alone or in combination with chemotherapy. Activation of the DNA damage response pathway and S-phase arrest induced by gemcitabine were assessed in pancreatic tumor cells with pharmacologic inhibition or siRNA depletion of GSK-3 kinases by immunoblotting, flow cytometry and immunofluorescence. RESULTS: 9-ING-41 treatment significantly increased pancreatic tumor cell killing when combined with chemotherapy. Inhibition of GSK-3 by 9-ING-41 prevented gemcitabine-induced S-phase arrest suggesting an impact on the ATR-mediated DNA damage response. Both 9-ING-41 and siRNA depletion of GSK-3 kinases impaired the activation of ATR leading to the phosphorylation and activation of Chk1. Mechanistically, depletion or knockdown of GSK-3 kinases resulted in the degradation of the ATR-interacting protein TopBP1, thus limiting the activation of ATR in response to single-strand DNA damage. CONCLUSIONS: These data identify a previously unknown role for GSK-3 kinases in the regulation of the TopBP1/ATR/Chk1 DNA damage response pathway. The data also support the inclusion of patients with PDAC in clinical studies of 9-ING-41 alone and in combination with gemcitabine.

The complexities of GSK-3β function and interactions with PI3K/AKT/mTOR signaling, cell cycling, and apoptotic pathways are poorly understood in the context of lymphomagenesis and cancer therapeutics. In this study, we explored the anti-tumor effects of the GSK-3β inhibitor, 9-ING-41, in lymphoma cell lines as a single agent and in combination with novel agents comprising BCL-2 inhibitor (Venetoclax), CDK-9 inhibitor (BAY-1143572) and p110δ-PI3K inhibitor (Idelalisib). Treatment of Daudi, SUDHL-4, Karpas 422, KPUM-UH1, and TMD8 lymphoma cell lines with 1 μM 9-ING-41 reduced cell viability by 40-70% (p

Many human diseases result from the dysregulation of the complex interactions between tens to thousands of genes. However, approaches for the transcriptional modulation of many genes simultaneously in a predictive manner are lacking. Here, through the combination of simulations, systems modelling and in vitro experiments, we provide a physical regulatory framework based on chromatin packing-density heterogeneity for modulating the genomic information space. Because transcriptional interactions are essentially chemical reactions, they depend largely on the local physical nanoenvironment. We show that the regulation of the chromatin nanoenvironment allows for the predictable modulation of global patterns in gene expression. In particular, we show that the rational modulation of chromatin density fluctuations can lead to a decrease in global transcriptional activity and intercellular transcriptional heterogeneity in cancer cells during chemotherapeutic responses to achieve near-complete cancer cell killing in vitro. Our findings represent a ‘macrogenomic engineering’ approach to modulating the physical structure of chromatin for whole-scale transcriptional modulation.

Glycogen synthase kinase-3β (GSK-3β), a serine/threonine protein kinase, is a complex regulator of numerous cellular functions. GSK-3β is a unique kinase which is constitutively active in resting and nonstimulated cells. GSK-3β has been implicated in a wide range of diseases including neurodegeneration, inflammation and fibrosis, noninsulin-dependent diabetes mellitus, and cancer. It is a regulator of NF-κB–mediated survival of cancer cells, which provided a rationale for the development of GSK-3 inhibitors targeting malignant tumors. Recent studies, many of them reported over the past decade, have identified GSK-3β as a potential therapeutic target in more than 15 different types of cancer. Whereas only active GSK-3β is expressed in cancer cell nucleus, aberrant nuclear accumulation of GSK-3β has been identified as a hallmark of cancer cells in malignant tumors of different origin. This review focuses on the preclinical and clinical development of GSK-3 inhibitors and the potential therapeutic impact of targeting GSK-3β in human cancer. Clin Cancer Res; 23(8); 1891–7. ©2017 AACR.

Tumours can be either benign or malignant. A first difference is that the primary malignant tumour infiltrates the surrounding tissue while, with very few exceptions, the benign tumours do not infiltrate. The second and main one is that, by definition, the malignant tumours are able to produce metastatic lesions in other organs. Finally, metastases can declare themselves even after period of years from the appearance of the first lesion. This is because of the third property of the malignant cells i.e. their ability to spread and then do not immediately grow into a detectable metastasis, but to be ‘dormant’ for a variable period.

Background: IRAK4, a serine/threonine kinase, was identified as a therapeutic target in hematological malignancies. IRAK4-mediated activation of NF-kappaB could play an important role in NF-kappaB-regulated survival and chemoresistance of cancer cells. CA-4948, a first-in-class small molecule inhibitor of IRAK4, has been tested in Phase 1 clinical trial with evidence of clinical activity in Non-Hodgkin's Lymphoma (NHL) patients. To support the development of companion diagnostic for CA-4948, we developed an immunohistochemical (IHC) assay and explored expression of potential biomarkers of response to CA-4948 in tumor biopsy samples obtained from NHL patients. Materials and Methods: IHC assay was developed and used for analysis of NF-kappaB p-p50 and p-IRAK1 expression in tumor biopsy samples obtained from 14 patients with NHL. Patients were defined according to their clinical response to CA-4948 treatment: stable disease (SD), 6 cases and progressive disease (PD), 8 cases. Results: We found nuclear and/or cytoplasmic expression of NF-kappaB p-p50 in all 6 SD cases treated with 50 mg QD (2 cases, tumor regression), 50 mg BID (1 case), 200 mg BID (1 case, tumor regression) and 400 mg BID (2 cases). Expression of NF-kappaB p-p50 was not detected in 7 of 8 cases with PD including patients treated with 50 mg QD (1 case), 100 mg QD (1 case), 100 mg BID (3 cases), 200 mg BID (1 case) and 400 mg BID (1 case). We found statistically significant correlation between expression of NF-kappaB p-p50 in tumor biopsy and SD in NHL patients treated with CA-4948 (p Conclusions: Although the cohort size is small, our findings suggest that expression of NF-kappaB p-p50 can serve as biomarker to predict SD in response to the treatment with IRAK4 inhibitor CA-4948 in NHL patients. NF-kappaB p-p50 selection strategy might be used in future clinical trials to identify NHL patients which are most likely to respond to CA-4948 in combination with chemotherapy or targeted therapeutics. Citation Format: Andrey Ugolkov, Maria Samson, Rosanna Hok, Reinhard von Roemeling, Robert Martell. Identification of NF-kappaB phospho-p50 as a predictive biomarker for IRAK4 inhibitor CA-4948 in patients with non-Hodgkin's lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 385.

Glycogen Synthase Kinase-3β (GSK-3β), a serine/threonine protein kinase, is an emerging therapeutic target in the treatment of human breast cancer. In this study, we demonstrate that the pharmacological inhibition of GSK-3 by two novel small molecule GSK-3 inhibitors, 9-ING-41 and 9-ING-87, reduced the viability of breast cancer cells but had little effect on non-tumorigenic cell growth. Moreover, treatment with 9-ING-41 enhanced the antitumor effect of irinotecan (CPT-11) against breast cancer cells in vitro. We next established two patient-derived xenograft tumor models (BC-1 and BC-2) from metastatic pleural effusions obtained from patients with progressive, chemorefractory breast cancer and demonstrated that 9-ING-41 also potentiated the effect of the chemotherapeutic drug CPT-11 in vivo, leading to regression of established BC-1 and BC-2 tumors in mice. Our results suggest that the inhibition of GSK-3 is a promising therapeutic approach to overcome chemoresistance in human breast cancer, and identify the GSK-3 inhibitor 9-ING-41 as a candidate targeted agent for metastatic breast cancer therapy.

PMCID: PMC4873437.-- et al., Loss of pigment epithelium-derived factor (PEDF, SERPINF1) in cancer cells is associated with poor prognosis and metastasis, but the contribution of stromal PEDF to cancer evolution is poorly understood. Therefore, we investigated the role of fibroblast-derived PEDF in melanoma progression. We demonstrate that normal dermal fibroblasts expressing high PEDF levels attenuated melanoma growth and angiogenesis in vivo, whereas PEDF-depleted fibroblasts exerted tumor-promoting effects. Accordingly, mice with global PEDF knockout were more susceptible to melanoma metastasis. We also demonstrate that normal fibroblasts in close contact with PEDF-null melanoma cells lost PEDF expression and tumor-suppressive properties. Further mechanistic investigations underlying the crosstalk between tumor and stromal cells revealed that melanoma cells produced PDGF-BB and TGFb, which blocked PEDF production in fibroblasts. Notably, cancer-associated fibroblasts (CAF) isolated from patient-derived tumors expressed markedly low levels of PEDF. Treatment of patient CAF and TGFβ-treated normal fibroblasts with exogenous PEDF decreased the expression of CAF markers and restored PEDF expression. Finally, expression profiling of PEDF-depleted fibroblasts revealed induction of IL8, SERPINB2, hyaluronan synthase-2, and other genes associated with tumor promotion and metastasis. Collectively, our results demonstrate that PEDF maintains tumor-suppressive functions in fibroblasts to prevent CAF conversion and illustrate the mechanisms by which melanoma cells silence stromal PEDF to promote malignancy., This study was funded by the following grants: T32 Carcinogenesis Training grant CA60013828 (N.G. Nwani), NCI R01 CA172669 (O.V. Volpert), and SAF2014-53819-R grant from Ministerio de Ciencia y Competitividad of Spain (B. Jimenez). A.P. Mazar, A. Ugolkov, and O. Dubrovskyi were supported by the Baskes Family Research Fund.

Advanced stage neuroblastoma is a very aggressive pediatric cancer with limited treatment options and a high mortality rate. Glycogen Synthase Kinase-3β (GSK-3β) is a potential therapeutic target in neuroblastoma. Using immunohistochemical staining, we observed positive GSK-3β expression in 67% of human neuroblastomas (34 out of 51 cases). Chemically distinct GSK-3 inhibitors (AR-A014418, TDZD8 and 9-ING-41), suppressed the growth of neuroblastoma cells whereas 9-ING-41, a clinically relevant small molecule GSK-3β inhibitor with broad spectrum pre-clinical antitumor activity, being the most potent. Inhibition of GSK-3 resulted in a decreased expression of the antiapoptotic molecule XIAP and an increase in neuroblastoma cell apoptosis. Mouse xenograft studies showed that the combination of clinically relevant doses of CPT-11 and 9-ING-41 led to greater antitumor effect than was observed with either agent alone. These data support the inclusion of patients with advanced neuroblastoma in clinical studies of 9-ING-41, especially in combination with CPT-11.

The histone deacetylases (HDACs) occur in 11 different isoforms, and these enzymes regulate the activity of a large number of proteins involved in cancer initiation and progression. The discovery of isoform-selective HDAC inhibitors (HDACIs) is desirable, as it is likely that such compounds would avoid some of the undesirable side effects found with the first-generation inhibitors. A series of HDACIs previously reported by us were found to display some selectivity for HDAC6 and to induce cell-cycle arrest and apoptosis in pancreatic cancer cells. In the present work, we show that structural modification of these isoxazole-based inhibitors leads to high potency and selectivity for HDAC6 over HDAC1-3 and HDAC10, while unexpectedly abolishing their ability to block cell growth. Three inhibitors with lower HDAC6 selectivity inhibit the growth of cell lines BxPC3 and L3.6pl, and they only induce apoptosis in L3.6pl cells. We conclude that HDAC6 inhibition alone is insufficient for disruption of cell growth, and that some degree of class 1 HDAC inhibition is required. Moreover, the highly selective HDAC6Is reported herein that are weakly cytotoxic may find use in cancer immune system reactivation.

Evasion of extracellular matrix detachment-induced apoptosis ('anoikis') is a defining characteristic of metastatic tumor cells. The ability of metastatic carcinoma cells to survive matrix detachment and escape anoikis enables them to disseminate as viable circulating tumor cells and seed distant organs. Here we report that αB-crystallin, an antiapoptotic molecular chaperone implicated in the pathogenesis of diverse poor-prognosis solid tumors, is induced by matrix detachment and confers anoikis resistance. Specifically, we demonstrate that matrix detachment downregulates extracellular signal-regulated kinase (ERK) activity and increases αB-crystallin protein and messenger RNA (mRNA) levels. Moreover, we show that ERK inhibition in adherent cancer cells mimics matrix detachment by increasing αB-crystallin protein and mRNA levels, whereas constitutive ERK activation suppresses αB-crystallin induction during matrix detachment. These findings indicate that ERK inhibition is both necessary and sufficient for αB-crystallin induction by matrix detachment. To examine the functional consequences of αB-crystallin induction in anoikis, we stably silenced αB-crystallin in two different metastatic carcinoma cell lines. Strikingly, silencing αB-crystallin increased matrix detachment-induced caspase activation and apoptosis but did not affect cell viability of adherent cancer cells. In addition, silencing αB-crystallin in metastatic carcinoma cells reduced the number of viable circulating tumor cells and inhibited lung metastasis in two orthotopic models, but had little or no effect on primary tumor growth. Taken together, our findings point to αB-crystallin as a novel regulator of anoikis resistance that is induced by matrix detachment-mediated suppression of ERK signaling and promotes lung metastasis. Our results also suggest that αB-crystallin represents a promising molecular target for antimetastatic therapies.

Background: We have previously identified Glycogen Synthase Kinase-3 beta (GSK-3β) nuclear accumulation as a hallmark of pancreatic ductal adenocarcinoma (PDAC) and demonstrated the antitumor effects of GSK-3β tool compound inhibitors in vivo (Ougolkov, Clin Cancer Res 2006). 9-ING-41 (Actuate Therapeutics Inc), a first-in-class, small-molecule potent selective GSK-3β inhibitor, has significant preclinical antitumor activity in PDAC. 9-ING-41 is synergistic with gemcitabine (GEM) in significantly reducing PDAC cell proliferation via impairment of ATR/Chk1 DNA damage response (Ding, Clin Cancer Res 2019). These data provided the rationale for inclusion of patients with PDAC in the 1801 phase 1/2 study evaluating 9-ING-41 alone and in combination with chemotherapy, including GEM and GEM plus nab-paclitaxel. Methods: Parts 1 and 2 of the 1801 phase 1/2 study evaluate the safety and tolerability of 9-ING-41 in patients with refractory malignancies. Part 1 establishes the recommended phase 2 study dose (RP2D) for 9-ING-41 monotherapy, while Part 2 assesses 9-ING-41 in combination with chemotherapies. For Part 1, patients received twice-weekly IV infusions of 9-ING-41 (21-day cycle). Based on prior treatment, Part 2 for those with PDAC consists of 9-ING-41 plus GEM (1000 to 1250 mg/m2 days 1 and 8; 21-day cycle) or 9-ING-41 plus GEM and nab-paclitaxel (125 mg/m2). Part 3 (Simon 2-stage phase 2 at the RP2D) will assess clinical benefit in patients with refractory PDAC treated with 9-ING-41-based combinations at the RP2D established in Part 2. Response is defined by response evaluation criteria in solid tumors (RECIST) criteria in evaluable lesions. The study is opening in 25 sites globally and will accrue approximately 300 patients. Results: To date, the study has accrued 34 patients with advanced solid tumors (n=33) or hematologic malignancies (n=1). Four dose levels (1, 2, 3.3, and 5 mg/kg) have been completed without dose-limiting toxicities (DLT). Part 2 of the study evaluating combination of 9-ING-41 with chemotherapy agents has been activated. Six patients with advanced PDAC have enrolled. One patient has completed 5 cycles of treatment with 9-ING-41 (1mg/kg) with stable disease (SD) as the best response. Another patient with SD as the best response has completed 6 cycles and now is joining the arm combining 9-ING-41 with GEM after disease progression. Four additional patients are awaiting first response assessment with enrollment ongoing. 9-ING-41-attributable AE to date are Grade 1 transient visual changes (color perception). Conclusions: 9-ING-41 is well tolerated. Preclinical data support the inclusion of patients with advanced PDAC on clinical studies of 9-ING-41. Citation Format: Benedito A. Carneiro, Malika Dhawan, Brittany Borden, Ludimila Cavalcante, Howard Safran, Andrey Ugolkov, Andrew P. Mazar, Daniel D. Billadeau, Francis J. Giles, Pamela Munster. GSK-3β blockade with 9-ING-41 in pancreas cancer: The 1801 phase 1/2 study [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B09.

Glycogen synthase kinase-3beta (GSK-3β) is a serine/threonine protein kinase that has been established as a therapeutic target in a broad spectrum of human malignancies. We have previously identified aberrant GSK-3β nuclear expression in bladder cancer (BC), and demonstrated that GSK-3β positively regulated BC cell survival and proliferation. Our objective was to evaluate the antitumor effects of the clinically viable agent 9-ING-41, a maleimide-based ATP-competitive GSK-3 inhibitor, which has broad spectrum antitumor activity and marked activity in reversing chemoresistance in a variety of pre-clinical models of human cancers. We used flow cytometry, Western immunoblotting, quantitative RT-PCR, BrDU incorporation and MTS assays to examine antitumor activity of 9-ING-41 in BC (T24, HT1376, RT4 cell lines). Additionally, we studied combination therapy of 9-ING-41 with gemcitabine and cisplatin, standard agents used for the treatment of patients with advanced BC, with cabozantinib, a multi kinase inhibitor, and with chloroquine, an autophagy inhibitor. A dose-dependent decrease in cancer cell proliferation was observed by MTS assay and BrdU incorporation assay with GI50 0.7μM (T24), 4.7 μM(HT1376), 2.2μM(RT4). Treatment with 9-ING-41 induced prominent cell cycle arrest (predominantly G2 arrest) in BC cells. Expression of cell cycle related proteins, including Cyclin D, and anti-apoptotic proteins, such as XIAP and Bcl-2, were significantly decreased as detected by Western immunoblotting and real time RT-PCR. Treatment with 9-ING-41 significantly potentiated the growth inhibitory effect of cisplatin and gemcitabine in cultured cells. In addition, combination therapy with 9-ING-41 and cabozantinib or chloroquine, significantly potentiated the effect of either single agent. Our data proved that a single treatment using 9-ING-41 is effective in BC cells. Combination treatment of 9-ING-41 with standard chemotherapeutic drugs or novel agents may provide a new therapeutic approaches in BC. These data provide a rational for the inclusion of patients with advanced BC in clinical studies of 9-ING-41. Citation Format: Hiroo Kuroki, Tsutomu Anraku, Vladimir Bilim, Masayuki Tasaki, Daniel Schmitt, Andrew Mazer, Francis J. Giles, Andrey Ugolkov, Yoshihiko Tomita. 9-ING-41, a novel inhibitor of glycogen synthase kinase-3beta (GSK-3β), is active as a single agent and within combination therapies in bladder cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4812.

Purpose: Basal-like breast tumors are typically (ER/PR/HER2) triple-negative and are associated with a high incidence of brain metastases and poor clinical outcomes. The molecular chaperone αB-crystallin is predominantly expressed in triple-negative breast cancer (TNBC) and contributes to an aggressive tumor phenotype in preclinical models. We investigated the potential role of αB-crystallin in brain metastasis in TNBCs. Experimental Design: αB-crystallin expression in primary breast carcinomas and brain metastases was analyzed by immunohistochemistry among patients with breast cancer with brain metastases. αB-crystallin was overexpressed or silenced in two different TNBC cell lines. The effects on cell adhesion to human brain microvascular endothelial cells (HBMEC) or extracellular matrix proteins, transendothelial migration, and transmigration across a HBMEC/astrocyte coculture blood–brain barrier (BBB) model were examined. In addition, the effects of overexpressing or silencing αB-crystallin on brain metastasis in vivo were investigated using orthotopic TNBC models. Results: In a cohort of women with breast cancer brain metastasis, αB-crystallin expression in primary breast carcinomas was associated with poor overall survival and poor survival after brain metastasis, even among patients with TNBC. Stable overexpression of αB-crystallin in TNBC cells enhanced adhesion to HBMECs, transendothelial migration, and BBB transmigration in vitro, whereas silencing αB-crystallin inhibited these events. αB-crystallin promoted adhesion of TNBC cells to HBMECs, at least in part, through an α3β1 integrin–dependent mechanism. αB-crystallin overexpression promoted brain metastasis, whereas silencing αB-crystallin inhibited brain metastasis in orthotopic TNBC models. Conclusion: αB-crystallin is a novel regulator of brain metastasis in TNBC and represents a potential biomarker and drug target for this aggressive disease. Clin Cancer Res; 20(1); 56–67. ©2013 AACR.

Sorafenib is a multikinase inhibitor approved for the systemic treatment of renal cell carcinoma (RCC). However, sorafenib treatment has a limited effect due to acquired chemoresistance of RCC. Previously, we identified glycogen synthase kinase-3 (GSK-3) as a new therapeutic target in RCC. Here, we observed that sorafenib inhibits proliferation and survival of RCC cells. Significantly, we revealed that sorafenib enhances GSK-3 activity in RCC cells, which could be a potential mechanism of acquired chemoresistance. We found that pharmacological inhibition of GSK-3 potentiates sorafenib antitumor effect in vitro and in vivo. Our results suggest that combining GSK-3 inhibitor and sorafenib might be a potential new therapeutic approach for RCC treatment.

We investigated a prognostic significance and the mechanism of aberrant nuclear expression of EZH2, a histone methyltransferase, in human renal cell carcinoma (RCC). We found nuclear EZH2 in 48 of 100 RCCs and it was significantly correlated with worse survival in RCC patients. We detected a decreased expression of miR-101 in 15 of 54 RCCs. We found that re-expression of miR-101 resulted in EZH2 depletion and decreased renal cancer cell proliferation. Our results show nuclear EZH2 as a prognostic marker of worse survival in human RCC, and identify miR-101 as a negative regulator of EZH2 expression and renal cancer cell proliferation.

BACKGROUND Stem cells were suggested to be present in human prostate cancer as a small population of distinct cells, which may contribute to carcinogenesis, tumor recurrence, and chemoresistance. To identify potential prostatic stem cells, we analyzed the expression of several potential stem cell markers in benign prostate and prostatic adenocarcinoma. METHODS CD44, CD133, Oct4, SOX2, and EZH2 expression was detected by immunohistochemical (IHC) staining using tissue microarray assays (TMA) composed of benign (non-neoplastic) prostatic tissue, high grade prostatic intraepithelial neoplasia (HGPIN), and prostatic adenocarcinoma. Positive staining was defined as 1+ ( 50%). RESULTS We found CD44 staining in 97% and 72% of benign + HGPIN and malignant lesions, respectively. CD133 staining was detected in a small fraction (4 of 67) of prostate carcinomas. We found that Oct4 nuclear expression was strongly associated with benign lesions and HGPIN but not prostate cancer (P

Purpose: Although recent studies have shown glycogen synthase kinase-3β (GSK-3β), a serine/threonine kinase, as a positive regulator of pancreatic, colon, and kidney cancer cell survival and proliferation, the role of GSK-3 in bladder cancer remains unknown. Our objectives were to determine the subcellular localization of GSK-3β and to evaluate the effect of GSK-3 inhibition in bladder cancer. Experimental Design: We used immunohistochemical staining and nuclear/cytosolic fractionation to determine the expression pattern of GSK-3β in human urothelial carcinomas. To study the effect of GSK-3 inhibition on bladder cancer cell proliferation and survival, we used pharmacologic inhibitors of GSK-3, RNA interference, MTS assay, bromodeoxyuridine incorporation assay, quantitative reverse transcriptase-PCR, and Western blotting. Results: We found aberrant nuclear accumulation of GSK-3β in 62% (43 of 69) and 91% (21 of 23) of noninvasive and invasive human urothelial carcinomas, respectively. GSK-3β nuclear staining was significantly associated with high-grade tumors (P < 0.001), advanced stage of bladder cancer (P < 0.05), metastasis (P < 0.05), and worse cause-specific survival (P < 0.05) in bladder cancer patients. Moreover, we found that pharmacologic inhibition or genetic depletion of GSK-3β resulted in decreased viability of bladder cancer cells. Conclusions: Our results suggest nuclear accumulation of GSK-3β as a novel prognostic marker in bladder cancer, show that GSK-3 contributes to urothelial cancer cell proliferation and survival, and identify GSK-3 as a potential therapeutic target in human bladder cancer. Clin Cancer Res; 16(21); 5124–32. ©2010 AACR.

Mortality in cancer patients usually occurs as a result of dissemination of their disease, a multi-factorial process called metastasis. This chapter discusses current understanding of how metastasis occurs and the pathways and cellular interactions that contribute to this process. Current views on lymphatic, haematogenous, and direct dissemination of metastatic cells through body cavities are considered, along with the contribution of tumour stromal cells, immune, and infiltrating cells derived from bone marrow, and angiogenesis to the metastatic process. Recent advances in characterizing metastatic niches and the contribution of specific organ sites and microenvironments to metastatic progression are presented, and the identification and characterization of circulating tumour cells and their role in metastasis are considered. Finally, representative molecular pathways as well as a sampling of new drugs in development for the treatment of metastatic disease are presented and referenced.

Background: Recurrent/metastatic head and neck squamous cell carcinoma (SCCHN) and salivary gland malignancies are difficult to treat with limited standard of care options at the present time. Glycogen Synthase Kinase-3beta (GSK-3beta), a serine/threonine protein kinase, has been implicated as a potential therapeutic target in human cancer. Our in vivo studies demonstrated that our novel GSK-3 inhibitors significantly potentiated the effects of conventional chemotherapy in patient-derived xenograft models of glioblastoma and breast cancer leading to regression of tumors. In order to develop a rationale to test our novel GSK-3 inhibitors in head and neck (H&N) malignancies, we evaluated the expression pattern of GSK-3beta in human H&N benign tissue and malignant tumors. Methods: We used immunohistochemical staining of H&N tumor tissue Microarray (TMA), 48 total cases (20 benign tissues, 28 malignant), to study the expression pattern of GSK-3beta. GSK-3beta nuclear accumulation was defined as positive staining of more than 50% of cancer cell nuclei throughout the tumor regardless of cytoplasmic staining. Results: Of the 20 malignant H&N samples (15 SCCHN, 1 nasopharyngeal and 5 other histology), 13 (65%) were found to have aberrant nuclear accumulation of GSK-3beta. Amongst SCCHN, 73% (11 of 15 samples) had aberrant nuclear accumulation of GSK-3beta. In contrast, none (0%) of the 11 benign non-salivary H&N tissue showed detectable expression of GSK-3beta. Of interest, 60% of salivary adenoid cystic carcinoma specimens and 44% of benign salivary gland tissue showed GSK-3beta expression. Conclusions: Our results demonstrate for the first time, that there is aberrant nuclear expression of GSK-3beta in SCCHN. This finding supports further exploring of our novel GSK-3beta inhibitor as a potential therapeutic target for recurrent/metastatic SCCHN and also, as a potential prognostic and predictive biomarker for risk of recurrent disease and chemo- or radio-resistance. Its role in salivary gland malignancies requires further studying. Citation Format: Maria Matsangou, Andrey Ugolkov, Timothy J. Taxter, Sandeep Samant, Andrew P. Mazar, Francis J. Giles. Aberrant nuclear expression of GSK-3beta in human head and neck carcinoma [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 1127. doi:10.1158/1538-7445.AM2017-1127

New therapies that challenge existing paradigms are needed for the treatment of cancer. We report a nanoparticle-enabled therapeutic approach to B-cell lymphoma using synthetic high density lipoprotein nanoparticles (HDL-NPs). HDL-NPs are synthesized using a gold nanoparticle template to control conjugate size and ensure a spherical shape. Like natural HDLs, biomimetic HDL-NPs target scavenger receptor type B-1, a high-affinity HDL receptor expressed by lymphoma cells. Functionally, compared with natural HDL, the gold NP template enables differential manipulation of cellular cholesterol flux in lymphoma cells, promoting cellular cholesterol efflux and limiting cholesterol delivery. This combination of scavenger receptor type B-1 binding and relative cholesterol starvation selectively induces apoptosis. HDL-NP treatment of mice bearing B-cell lymphoma xenografts selectively inhibits B-cell lymphoma growth. As such, HDL-NPs are biofunctional therapeutic agents, whose mechanism of action is enabled by the presence of a synthetic nanotemplate. HDL-NPs are active in B-cell lymphomas and potentially, other malignancies or diseases of pathologic cholesterol accumulation.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of cancer death, with a 5-year overall survival rate Histopathological comparison of sections from PDX tumor, organoids, and primary PDAC from a 63-year-old female patient were performed on paraffin embedded tissue. H&E and immunohistochemical staining for cytokeratins (CK7, CK20), p53, Claudin-4, and CEA were performed. DNA and mRNA sequencing was performed. Both PDX and organoids exhibited histopathological features remarkably consistent with the original patient tumor including the histologic grade (moderately differentiated), cytological appearance (irregular nuclear membranes, open chromatin and prominent nucleoli), mitotic activity (5 -7/10 HPF), and immunohistochemical profile. The PDX and organoids demonstrated diffuse moderate-to-strong positivity for CK7, CEA, p53, and Claudin-4 and focal weak positivity for CK20 - all similar to the primary tumor. The immunohistochemical staining pattern was consistent with mRNA sequencing of the primary tumor which showed that CEA, Claudin-4 and p53 expression were ∼960-fold, ∼27-fold and ∼3 fold higher respectively (vs. benign pancreatic tissue). DNA sequencing revealed somatic mutations in KRAS and TP53 genes seen in >90% and ∼70% of PDACs respectively, and a few rare somatic mutations, such as a sodium leak channel (NALCN) mutation, seen in ∼3% of PDAC. Both PDX and organoid models of PDAC maintain key histological features, immunohistochemical profile and basic gene expression pattern akin to the primary tumor. These findings suggest that PDXs and organoids have the potential to serve as reliable pathophysiological models for optimizing individual therapy for patients with PDAC. Citation Format: Isabel Romero Calvo, Ashwin Akki, Andrey Ugolkov, Mary M. Buschmann, Samantha M. Sparrow, Teresa Barry, Margaret Eber, Tongjun Gu, Shuang Qin Zhang, Hedy Kindler, William Dale, Kevin Roggin, Andrew P. Mazar, Kevin P. White, Christopher R. Weber. Organoids and patient-derived tumor xenograft of pancreatic adenocarcinoma share morphological and genetic features with the primary tumor. [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 4272.

Glycogen Synthase Kinase-3beta (GSK-3beta), a serine/threonine protein kinase, has been demonstrated to be potential therapeutic target in human breast cancer. Our objective was to evaluate novel GSK-3 inhibitors alone and in combination with chemotherapeutic drugs for the targeted therapy of breast cancer. Using a short-term treatment, we found that the GSK-3 inhibitor 9ING41 significantly potentiates the antitumor effects of CPT-11, cisplatin and 5-FU to inhibit breast cancer cell growth. We established hormone-refractory BC-1 and BC-2 patient-derived xenograft (PDX) tumor models from metastatic pleural effusions that were obtained from breast cancer patients. We considered BC-1 and BC-2 PDX tumors as chemoresistant, because metastatic disease progressed in both cases in despite of the fact that patients received many cycles of chemotherapy. Although we found that BC-1 and BC-2 PDX tumors express estrogen receptor (ER), both PDX tumors carried activating mutations in ESR1. These mutations confer ligand-independent activity of the ER in tamoxifen-resistant breast tumors. We found that BC-1 and BC-2 PDX tumors grew without estradiol supplementation in immunodeficient mice, which suggests a hormone-refractory nature of these tumors. We found that GSK-3 inhibitor 9ING41 potentiates the effects of chemotherapeutic drug CPT-11, and leads to the regression of BC-1 and BC-2 breast PDX tumors. Our results demonstrate inhibition of GSK-3 as a promising therapeutic approach to overcome breast cancer chemoresistance, and identify GSK-3 inhibitor 9ING41 as a drug candidate for the targeted therapy of human breast cancer. Citation Format: Andrey Ugolkov, Irina Gaisina, Kevin White, Alan Kozikowski, Thomas O’Halloran, Andrew Mazar. GSK-3 inhibitor 9ING41 potentiates the antitumor effects of CPT-11 in human breast cancer. [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 3078.

Self-assembled peptide amphiphiles (PAs) consisting of hydrophobic, hydrogen bonding, and charged hydrophilic domains form cylindrical nanofibers in physiological conditions and allow for the presentation of a high density of bioactive epitopes on the nanofiber surface. We report here on the use of PAs to form multifunctional nanostructures with tumoricidal activity. The combination of a cationic, membrane-lytic PA co-assembled with a serum-protective, pegylated PA was shown to self-assemble into nanofibers. Addition of the pegylated PA to the nanostructure substantially limited degradation of the cytolytic PA by the protease trypsin, with an eight-fold increase in the amount of intact PA observed after digestion. At the same time, addition of up to 50% pegylated PA to the nanofibers did not decrease the in vitro cytotoxicity of the cytolytic PA. Using a fluorescent tag covalently attached to PA nanofibers we were able to track the biodistribution in plasma and tissues of tumor bearing mice over time after intraperitoneal administration of the nanoscale filaments. Using an orthotopic mouse xenograft model of breast cancer, systemic administration of the cytotoxic pegylated nanostructures significantly reduced tumor cell proliferation and overall tumor growth, demonstrating the potential of multifunctional PA nanostructures as versatile cancer therapeutics.

Recently, we have identified GSK-3 as a new therapeutic target in renal cell cancer (RCC). miR-199a could potentially downregulate GSK-3β expression. Here, we found a decreased miR-199a expression in 59% (32 of 54) of RCCs and it was correlated with higher tumor stage (p < 0.05) and nuclear overexpression of GSK-3β (p < 0.05). We show that re-expression of miR-199a downregulates GSK-3β and suppresses cancer cell growth. Our results demonstrate low miR-199a expression as a feature of advanced RCCs, identify miR-199a as a negative regulator of GSK-3β, and suggest re-expression of pre-miR-199a as a new potential treatment of RCC.

BACKGROUND: Glycogen Synthase Kinase-3 (GSK-3), a positive regulator of NF-kappaB-mediated survival of cancer cells, has been identified as a potential therapeutic target for the treatment of GBM. We hypothesized that the inhibition of GSK-3 may overcome NF-kappaB-associated chemo- and radioresistance in human GBM. METHODS: We used GBM6 and GBM12 patient-derived xenograft (PDX) orthotopic tumor models, enabled for bioluminescence imaging (BLI) through luciferase modification, for evaluating the novel GSK-3 inhibitor 9-ING-41, when used in combination with genotoxic chemotherapy or radiotherapy. In vivo imaging system (IVIS) was used to study the effect of mono- and combination treatments, along with determination of survival benefit from treatment after intracranial transplantation of GBM tumor. RESULTS: BLI of animal subjects revealed that NF-kappaB is constitutively active in orthotopic GBM tumor expressing an NF-kappa luciferase reporter. Intravenous injection of 9-ING-41 significantly reduced the bioluminescence of orthotopic GBM PDX, indicative of reduced NF-kappaB transcriptional activity. When used in combination with the DNA alkylator CCNU, 9-ING-41 significantly increased CCNU anti-tumor activity against orthotopic GBM12 (no response to CCNU monotherapy) or GBM6 (partial response to CCNU monotherapy) xenografts, as indicated by the absence of tumor bioluminescence signal in mouse brain and by significantly increased animal subject survival. The treatment with CCNU + 9-ING-41 resulted in "apparent cure" for all mice with intracranial GBM6 and GBM12 tumors, as supported by histological evaluation that revealed a complete absence of cancer cells in mouse brain. CONCLUSIONS: Our results suggest that GSK-3 inhibitor 9-ING-41, a novel clinical drug candidate, enhances the efficacy of genotoxic therapy for human GBM, and warrants consideration for clinical evaluation. The combination of 9-ING-41 and radiotherapy, for the treatment of GBM12 orthotopic PDX tumors, is ongoing and will be presented.

Glioblastoma multiforme (GBM) is fatal in nearly all instances, and responds poorly to current standards of care. GBMs exhibit resistance to chemotherapy which leads to tumor recurrence following initial surgical debulking. We have recently developed an 80 nm liposome containing a novel hydrophobic microtubule disrupting piperazine. This novel nanostructure, called IM-1 nanobin, contains 500-1000 piperazine drug molecules encapsulated in the hydrophobic inner leaflet of the lipid bilayer in each liposome. This nanoparticle inhibited the proliferation of GBM cells in vitro, although its cytotoxicity was reduced (3-5 fold) compared to free drug dissolved in DMSO. Results from FACS analysis showed that sub-micromolar concentrations of IM-1 caused G2/M phase cell cycle arrest and apoptosis of U87 GBM cells, as well as early passage GBM cells derived from a patient-derived xenograft (PDX). In collaboration with the Northwestern Brain Tumor Institute, we have established a panel of PDX. Since these tumors are not propagated in culture, they preserve the mixture of tumor cells and stroma critical for conducting meaningful therapy response experiments. IM-1 was evaluated in GBM PDX propagated in subcutaneous and intracranial compartments. In mice bearing subcutaneous PDX tumors, IM-1 treatment delayed the growth of the tumors compared to free drug alone; orthotopic GBM PDX studies are ongoing. Our results show that a novel liposome encapsulated piperazine, IM-1, is a promising new nanostructure for development as a therapeutic for treating patients with GBM. Citation Format: Elden P. Swindell, Andrey Ugolkov, Christian Freguia, Oleksii Dubrovskyi, Patrick L. Hankins, Jeong Yang, Jeffrey J. Raizer, James P. Chandler, Charles David James, Andrew P. Mazar, Thomas V. O'Halloran. Liposomes containing piperazine compounds inhibit tumor growth in a patient-derived xenograft model of glioblastoma multiforme. [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 4389. doi:10.1158/1538-7445.AM2015-4389

Triple negative breast cancer represents an aggressive malignancy for which few targeted therapies exist. The embryonic morphogen Nodal is re-expressed in highly aggressive breast cancers and reduction of Nodal signaling decreases tumor cell metastatic characteristics. This represents a potential avenue for the development of therapeutics aimed at inhibiting the Nodal pathway. To explore this further, we evaluated Nodal expression in breast cancer cells following chemotherapy. In vitro treatment of MDA-MB-231 and MDA-MB-468 human breast cancer cell lines with Doxorubicin, a chemotherapy commonly used for the treatment of malignant breast cancer, resulted in the generation of surviving subpopulations that retained Nodal expression (>80%) and remained viable. To validate these findings in vivo, we analyzed Doxorubicin treated metastatic patient derived breast cancer xenografts (PDX) which displayed a residual population of Nodal positive cells when analyzed by immunohistochemistry. Based on these findings, we hypothesize that targeting Nodal in a combinatorial approach with chemotherapy will lead to a reduction in remaining viable populations of cancer cells. When we utilized an anti-Nodal neutralizing antibody to inhibit Nodal signaling, antibody treatment reduced cell proliferation, attachment and increased rates of apoptosis in Doxorubicin treated breast cancer cell lines. Decreases in phosphorylation of Histone 3, a marker of cellular proliferation, and increases in the cleavage of PARP, correlating to induction of apoptosis, were noted in response to antibody treatment. These data suggest that Nodal signaling plays a critical role in the growth of metastatic breast cancer cells and targeting Nodal may improve therapeutic outcome in malignancies such as triple negative breast cancer. The initial results highlight translational potential for the development of humanized antibodies capable of inhibiting Nodal function. Citation Format: Thomas M. Bodenstine, Grace S. Chandler, Naira V. Margaryan, Luigi Strizzi, Alina Gilgur, Elisabeth A. Seftor, Richard E B Seftor, Zhila Khalkhali-Ellis, Andrey Ugolkov, Andrew P. Mazar, Mary J C Hendrix. Targeting the embryonic morphogen Nodal reduces viability of doxorubicin-treated breast cancer cells in vitro. [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 4378. doi:10.1158/1538-7445.AM2015-4378

Neuroblastoma is a devastating pediatric cancer and most patients older than 18 months present with multi-organ metastatic disease. High grade or recurrent disease is refractory to treatment with chemotherapy and almost uniformly fatal. Because GSK-3beta has been shown to be a positive regulator of NF-kappaB-mediated survival and chemoresistance in cancer cells, we hypothesize that the inhibition of GSK-3 may have potential therapeutic effects in neuroblastoma. To test this premise we used small molecule inhibitors, Western blotting, apoptotic and MTS assays to study the effect(s) of GSK-3 inactivation in neuroblastoma cell lines SK-N-DZ and SK-N-BE(2). Using chemically distinct GSK-3 inhibitors (AR-A014418, TDZD8 and 9-ING-41), we found that pharmacological inhibition of GSK-3 led to a decrease in proliferation and survival of neuroblastoma cells. We observed that inhibition of GSK-3 results in decreased expression of the anti-apoptotic molecules Bcl-XL and XIAP (NF-kappaB target genes) and a subsequent increase in neuroblastoma cell apoptosis. Moreover, we show that our novel GSK-3 inhibitor 9-ING-41 enhances the antitumor effects of irinotecan in neuroblastoma cells. Our results demonstrate that GSK-3 positively regulates neuroblastoma cell survival and proliferation and suggest that the inhibition of GSK-3 is a promising new approach for the treatment of neuroblastoma. Citation Format: Oleksii Dubrovskyi, Andrey Ugolkov, Irina Gaisina, Gennadiy Bondarenko, Luigi Strizzi, Naira Margaryan, Thomas O'Halloran, Alan Kozikowski, Mary Hendrix, Andrew Mazar. Targeting GSK-3: a new approach for the treatment of neuroblastoma. [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 3287. doi:10.1158/1538-7445.AM2015-3287

Patient-derived xenograft (PDX) tumor models have emerged as new and effective models for developing novel anticancer therapies and personalized use of chemotherapeutic drugs. The PDX approach is based on the transplantation of primary or metastatic human tumors into highly immunodeficient NOD scid gamma (NSG) mice followed by continuous propagation of the established engrafment in mice. Clinicians can evaluate the effects of cancer drugs on their patients’ personalized tumor grafts enabling them to select the best treatment for the cancer patient. Here, we report that PDX tumors engrafted in NSG mice are susceptible to formation of B-cell lymphomas. We xenografted primary or metastatic human tumor fragments into NSG mice and found that tumors generated from patients’ samples of breast (1 out 3 cases), colon (2 out of 6 cases), pancreatic (1 out of 3 cases), bladder (1 out of 2 cases) and renal (1 out of 2 cases) cancer were histologically similar to lymphoid neoplasm. Moreover, we found that the first passage (F1) of some breast and pancreatic cancer PDX tumors could grow as a lymphoid neoplasm in one mouse and as an adenocarcinoma in another mouse after initial transplantation of the pieces from the same human tumor graft (F0). Whereas subcutaneous PDX tumors resembling primary human carcinoma histology were slow growing and non-metastatic, we found that subcutaneous PDX lymphoid neoplasms were fast growing and formed large metastatic lesions in lymph nodes, liver, lungs and spleen of the mouse. Immunohistochemical staining confirmed that lymphoma cells express human leucocyte common antigen CD45 and B-cell antigen CD19/20. By using Epstein-Barr Virus-encoded RNA (EBER) in situ hybridization, we found that PDX lymphoma cells were EBER-positive. Because B-cells are typically present in any solid malignant tumor, B-cell PDX lymphomas may evolve in a wide range of PDX tumor models. Our results suggest that histolopathological evaluation and lymphoid marker testing should be performed as part of the initial model characterization in order to exclude B-cell lymphomas during the development of PDX tumor model from solid human carcinoma. Citation Format: Gennadiy Bondarenko, Andrey Ugolkov, Piotr Kulesza, Stephen M. Rohan, Oleksii Dubrovskyi, Demirkan Gursel, Jeremy V. Mathews, Thomas V. O'Halloran, Jian-Jun Wei, Andrew P. Mazar. Patient-derived tumor xenograft are susceptible to formation of B-cell lymphoma after initial transplantation of human carcinoma to immunodeficient mice. [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 1464. doi:10.1158/1538-7445.AM2015-1464

Glioblastoma (GBM) is, in essence, an incurable cancer, with most patients surviving 12-15 months following initial diagnosis. Previously published studies identified Glycogen Synthase Kinase-3 (GSK-3) as a new therapeutic target in GBM. Because GSK-3beta is a positive regulator of NF-kappaB-mediated survival and chemoresistance in cancer cells, we hypothesize that the inhibition of GSK-3 may overcome NF-kappaB-mediated chemoresistance to conventional drugs in human GBM. Using IVIS imaging of live mice, we found that: 1) NF-kappaB is constitutively active in orthotopic GBM patient-derived xenograft (PDX) tumors expressing an NF-kappa luciferase reporter; and 2) a single intravenous injection of our novel GSK-3 inhibitor 9-ING-41 (25 mg/kg) significantly reduced NF-kappaB transcriptional activity in orthotopic GBM PDX. Using 3 different orthotopic GBM PDX- tumor models, enabled for bioluminescence imaging through luciferase modification, we evaluated antitumor effects of 9-ING-41, alone as well as in combination with irinotecan, CCNU and temozolomide. Our in vivo results revealed that treatment with a combination of 9-ING-41 and irinotecan delays GBM PDX tumor growth, relative to either agent as a monotherapy, and, even more promising, 9-ING-41+CCNU leads to a complete tumor regression. Histological evaluation of mouse brain confirmed the absence of cancer cells and a formation of cyst at the location of intracranial tumor in mice treated with 9-ING-41+CCNU. Our results provide a rationale to advance 9-ING-41 for clinical evaluation in treating GBM, especially when combined with CCNU cytotoxic therapy. Citation Format: Andrey Ugolkov, Oleksii Dubrovskyi, Irina Gaisina, Alex Yemelyanov, Gennadiy Bondarenko, Charles James, James Chandler, Thomas O'Halloran, Alan Kozikowski, Jeffry Raizer, Andrew Mazar. Targeting GSK-3: a novel approach to enhance glioblastoma chemosensitivity. [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 2699. doi:10.1158/1538-7445.AM2015-2699

GSK3 is an attractive therapeutic target in cancer, known for its role in regulating proliferation, differentiation, metabolism, and apoptosis. Previous studies demonstrate the effectiveness of GSK3 inhibition on established glioma cell lines and patient-derived glioma stem cell lines in vitro and in vivo. In glioma cell lines, GSK3 inhibition induces apoptosis through c-MYC activation, mitochondrial destabilization, and reduction of NF-κB activity. We have characterized a novel set of GSK3 inhibitors for their ability to inhibit glycogen synthase phosphorylation, reduce levels of XIAP, and induce cell death in cancer cells. However, it is uncertain if this mechanism is functional with respect to cancer stem cells and glioma tumor subtype. The need to investigate the mechanistic effects of GSK3 in cancer stem cells is important given their malignancy, innate resistance to therapy, and tumorigenicity. Moreover, the intracellular signaling and transcription networks may differ in glioma stem cells, particularly among cells with different subtypes. We have recently demonstrated that cancer stem cells isolated from glioma patients can be segregated into either a proneural or mesenchymal subtype based on their gene expression pattern. The oncogenic activity of genes like c-MYC in glioma stem cells and differences between glioma stem cell subtypes, such as NF-κB activation, raises questions as to whether GSK3 inhibition will be effective against both subtypes and if their effects utilize distinct mechanisms of inhibition. In this study, we examine the effects of two established and two novel GSK3 inhibitors on glioma stem cells with respect to tumor subtype and investigate their mechanisms of action. Our in vitro data shows that GSK3 inhibition significantly reduces growth and causes cell death in both proneural and mesenchymal glioma stem cells. Using a glioma stem cell xenograft model, we test the effectiveness of GSK3 inhibition as a single agent and in conjunction with clinically-approved chemotherapeutic agents. The characterization of cancer stem cell inhibitors and their effectiveness in different tumor subtypes has significant clinical implications. Our work supports the therapeutic potential of novel GSK3 inhibitors for the treatment of malignant gliomas. Note: This abstract was not presented at the meeting. Citation Format: Angel Alvarez, Andrey Ugolkov, Irina Gaisina, Alan P. Kozikowski, Kaushal Joshi, Sunghak Kim, Ichiro Nakano, Jeffrey J. Raizer, Andrew P. Mazar, Bo Hu, Shi-Yuan Cheng. GSK3 signaling is critical to glioma stem cell growth and survival. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1941. doi:10.1158/1538-7445.AM2014-1941

The urokinase plasminogen activator receptor (uPAR) plays a role in tumor progression and has been proposed as a target for the treatment of cancer. We recently described the development of a novel humanized monoclonal antibody that targets uPAR and has anti-tumor activity in multiple xenograft animal tumor models. This antibody, ATN-658, does not inhibit ligand binding (i.e. uPA and vitronectin) to uPAR and its mechanism of action remains unclear. As a first step in understanding the anti-tumor activity of ATN-658, we set out to identify the epitope on uPAR to which ATN-658 binds. Guided by comparisons between primate and human uPAR, epitope mapping studies were performed using several orthogonal techniques. Systematic site directed and alanine scanning mutagenesis identified the region of aa 268-275 of uPAR as the epitope for ATN-658. No known function has previously been attributed to this epitope Structural insights into epitope recognition were obtained from structural studies of the Fab fragment of ATN-658 bound to uPAR. The structure shows that the ATN-658 binds to the DIII domain of uPAR, close to the C-terminus of the receptor, corroborating the epitope mapping results. Intriguingly, when bound to uPAR, the complementarity determining region (CDR) regions of ATN-658 closely mimic the binding regions of the integrin CD11b (αM), a previously identified uPAR ligand thought to be involved in leukocyte rolling, migration and complement fixation with no known role in tumor progression of solid tumors. These studies reveal a new functional epitope on uPAR involved in tumor progression and demonstrate a previously unrecognized strategy for the therapeutic targeting of uPAR.

NF-kappaB is known to regulate human breast cancer progression, metastasis and chemoresistance. Glycogen Synthase Kinase-3beta (GSK-3beta), a serine/threonine protein kinase, is an essential positive regulator of NF-kappaB transcriptional activity and thereby GSK-3beta may represent a potential therapeutic target in human breast cancer. Our objectives were to determine the expression pattern of GSK-3beta in human breast cancer, to assess the effect of GSK-3 inhibition on breast cancer cell proliferation, survival and chemoresistance, and to evaluate our lead GSK-3 inhibitors alone and in combination with chemotherapeutic drugs for the targeted therapy of breast cancer. Using nuclear/cytosolic fractionation, Western immunoblotting and immunohistochemical staining, we observed aberrant nuclear accumulation of GSK-3beta in five breast cancer cell lines and in 7 of 8 primary human breast carcinomas and corresponding lymph node metastases whereas no detectable expression of GSK-3beta was found in benign breast tissue. Pharmacological inhibition of GSK-3 led to a decrease in proliferation and survival of breast cancer cells. Our in vitro comparison studies demonstrated that our lead GSK-3 inhibitor 9-ING-41 was significantly (30 times) more effective than GSK-3 inhibitor LY2090314 (Eli Lilly), currently in mid-stage clinical trials, in terms of growth inhibition of breast cancer cells. Inhibition of GSK-3 resulted in decreased expression of the NF-kappaB target genes Bcl-2 and XIAP and induction of apoptosis. Moreover, our lead GSK-3 inhibitor 9-ING-41 and doxorubicin acted synergistically to suppress growth of breast cancer cells. Our preliminary in vivo experiments demonstrated that monotherapy with our lead GSK-3 inhibitor 9-ING-41 (20 mg/kg) for 48 hours inhibited proliferation (as shown by BrDU assay) and induced apoptosis (as shown by TUNEL assay) in MDA-MB-468 orthotopic xenograft tumors. Moreover, in vivo toxicology study demonstrated that intravenous injections of 9-ING-41 did not adversely affect mouse complete blood counts or cause overt pathological changes in mouse organs. Our results identify GSK-3beta as a new potential drug target in breast cancer and suggest that inhibition of GSK-3 is a novel therapeutic approach to overcome NF-kappaB-mediated chemoresistance in breast cancer. Citation Format: Andrey Ugolkov, Irina Gaisina, Dmitry Malin, Peter Kulesza, Alan Kozikowski, Vincent Cryns, Andrew Mazar. Inhibition of GSK-3: A novel therapeutic approach for breast cancer treatment. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B068.