Search

Purpose: Angiogenesis inhibitors have shown clinical benefit in patients with advanced renal cell cancer, but further therapeutic improvement is needed. Vascular endothelial growth factor (VEGF) Trap is a newly developed VEGF-blocking agent with stronger affinity and broader activity than the anti-VEGF antibody bevacizumab. In this study, we tested the activity of VEGF Trap in an orthotopic murine model of renal cancer with spontaneous lung metastases. Experimental Design: Murine syngeneic renal cell carcinoma cells (RENCA) transfected with a luciferase-expressing vector were injected into the renal capsule of BALB/c mice. I.p. treatment with VEGF Trap or control protein (10 or 25 mg/kg twice weekly) was started shortly after tumor injection to prevent tumor development (prevention model) or after established tumors were formed to inhibit tumor growth and metastasis formation (intervention model). Results: In the prevention model, VEGF Trap inhibited tumor growth by 87 ± 14% compared with control (P = 0.007) and significantly prolonged survival. In the intervention model, VEGF Trap inhibited tumor growth by 74 ± 9% (P < 0.001) and the formation of lung metastases was inhibited by 98% (P < 0.004). Microvascular density was reduced by 66% due to VEGF Trap treatment (P < 0.001). In addition, VEGF Trap prevented fibrinogen leakage into the tumor microenvironment representative for reduced vascular leaking as shown by immunohistochemical staining. Conclusions: VEGF Trap is a potent inhibitor of RENCA tumor growth and metastasis formation and blocks the biological function of VEGF in vivo. These results support further clinical development of VEGF Trap for renal cell cancer and other cancer types.

Combination of two differentiation agents such as phenylbutyrate (PB) and 13-cis-retinoic acid (CRA) has been shown to have an additive inhibitory effect on tumor growth in preclinical studies. In this report we explored the hypotheses that these "cytostatic" agents may have a greater antitumor activity in combination with "cytotoxic" compounds and their biological effect may be sequence-dependent.The antitumor activity of combination of PB and CRA with paclitaxel (TX ) and doxorubicin (DOXO) on human prostate and colon carcinoma cell lines was assessed both in vitro and in vivo. The effect on cell cycle, apoptotic rate, cyclin expression and induction of p21 expression was also determined.Following treatment of tumor cells with PB + CRA + TX or DOXO, inhibition of tumor cell growth was greatly enhanced as compared to PB + CRA, TX or DOXO alone, with90% growth inhibition. However, when the cells were pretreated with PB + CRA followed by TX or DOXO, the enhanced inhibition was abolished suggesting a protective effect to this sequence. Interestingly treatment with PB + CRA restored sensitivity to DOXO in PC-3 human prostate cancer cell line. PB + CRA induced p21 expression and cell-cycle arrest in G1 phase, while TX and DOXO induced G2/M arrest. p21 and p53-deficient colon carcinoma cell lines were more sensitive to the effect of PB + CRA and TX as single agents and in combination, as compared to the wild type cells. When p21-deficient cells were pretreated with PB + CRA followed by TX the protective effect was still observed. Treatment of tumor cells with combination of these drugs induced cell cycle delay at multiple mitotic checkpoints before undergoing apoptosis. Tumor growth was significantly inhibited and delayed in animals treated with either TX or concomitantly with TX and PB + CRA as compared to control. Animals treated with all three agents demonstrated further growth inhibition or delay than the TX alone or PB + CRA arm.These results suggest a rational therapeutic approach for combination of differentiation-inducing agents with cytotoxic drugs given concomitantly, but not sequentially.

A rapid, sensitive and selective method was developed and validated using LC/MS/MS for determination of MS-275 in human plasma. Sample preparation involved a single step liquid-liquid extraction by the addition of 0.2 ml of plasma with 5 ml acetonitrile/n-butyl-chloride. Separation of the compounds of interest, including the internal standard paclitaxel, was achieved on a Waters X-Terra C(18) (50 mm x 2.1mm i.d., 3.5 microm) analytical column using a mobile phase consisting of acetonitrile/ammonium acetate (pH 2.9; 2mM)(60:40, v/v) containing 0.1% formic acid and isocratic flow at 0.15 ml/min for 3 min. The analytes were monitored by tandem-mass spectrometry with electrospray positive ionization. Linear calibration curves were generated over the range of 0.5-100 ng/ml with values for the coefficient of determination of >0.99. The values for both within day and between day precision and accuracy were well within the generally accepted criteria for analytical methods (

No predictors of a complete pathologic response (pT0) to neoadjuvant chemotherapy (NAC) in muscle-invasive bladder carcinoma have been established. We performed a retrospective analysis of 50 patients to identify potential predictors. Our results showed that the presence of additional transitional cell variants on pathologic examination (mixed tumors) predicted against pT0, suggesting the avoidance of NAC and its morbidity in these patients with mixed tumors.Randomized trials have supported the use of cisplatin-based neoadjuvant chemotherapy (NAC) in muscle-invasive bladder carcinoma (MIBC) owing to the survival advantage, which has correlated with downstaging of the cancer to pT0. Only 30% to 40% of patients receiving NAC have attained a pT0 response at cystectomy; the remaining have either residual disease or progression. We aimed to identify the factors that could predict a pT0 response to NAC.Of 336 patients who had undergone robotic cystectomy at our institute from May 2007 to March 2014, we identified 50 patients who had undergone NAC for MIBC. We conducted a retrospective study, dividing these 50 patients into 2 groups, those with and without a pT0. Factors, including age, histologic features, hydronephrosis at initial presentation, and chemotherapy type, were examined by both univariate and multivariate logistic regression analysis.Of the 50 patients, 14 (28%) had pT0 at cystectomy, 20 (40%) had progressive disease, and 16 (32%) had residual disease. The median age was 67.5 years, the median glomerular filtration rate at presentation was 87.5 mL/min, the patients had undergone a median of 3 NAC cycles, and the median time from the end of chemotherapy to surgery was 4 weeks. The odds of a pT0 response for pure urothelial carcinoma (UC) were approximately 11 times greater relative to cancers with transitional cell variant histologic features or mixed tumors (odds ratio 0.09, 95% confidence interval 0.021-0.380; P = .0011), including squamous, glandular differentiation, small cell, micropapillary, sarcomatoid, nested component, lymphoepithelioma-like, and plasmacytoid variants.The presence of pure UC favored a pT0 response to NAC compared with those with variant histologic features or mixed tumors. These potential predictors warrant prospective validation to allow the ideal selection of patients for NAC.

Drug combinations can improve angiostatic cancer treatment efficacy and enable the reduction of side effects and drug resistance. Combining drugs is non-trivial due to the high number of possibilities. We applied a feedback system control (FSC) technique with a population-based stochastic search algorithm to navigate through the large parametric space of nine angiostatic drugs at four concentrations to identify optimal low-dose drug combinations. This implied an iterative approach of in vitro testing of endothelial cell viability and algorithm-based analysis. The optimal synergistic drug combination, containing erlotinib, BEZ-235 and RAPTA-C, was reached in a small number of iterations. Final drug combinations showed enhanced endothelial cell specificity and synergistically inhibited proliferation (p

BACKGROUND Linomide, Figure 1, produces robust and consistent in vivo growth inhibition of prostate cancer models via its anti-angiogenic activity and inhibition of autoimmune encephalomyelitis models of multiple sclerosis (MS). MS clinical trials were discontinued because of unacceptable toxicity, due to dose-dependent induction of proinflammation. METHODS Therefore, linomide analogs were initially screened to determine their in vivo potency to inhibit growth of the Dunning R-3327 AT-1 rat prostate cancer model in rats and their potency to inhibit angiogenesis in a Matrigel assay in mice. RESULTS Based upon its superior potency (i.e., 30- to 60-fold more potent than linomide) in these assays and its lack of a proinflammation in the Beagle-dog, ABR-215050 (tasquinimod), Figure 1, was characterized for dose-response ability to inhibit the growth of a series of four additional human and rodent prostate cancer models in mice. Pharmacokinetic analysis following oral dosing documented that blood and tumor tissue levels of ABR-215050 as low as 0.5-1 µM are therapeutically effective. This efficacy is correlated with inhibition of angiogenesis in a variety of assays (endothelial capillary tube formation, aortic ring assay, chorioallantoic membrane assay, real-time tumor blood flow and PO2 measurements, tumor blood vessel density, and tumor hypoxic and apoptotic fractions). CONCLUSIONS Based upon its robust and consistent anti-angiogenic activity and thus tumor growth, ABR-215050 has entered clinical trials for the treatment of prostate cancer. (Less)

Purpose This phase I study was conducted to determine the recommended dose of enzastaurin, an oral protein kinase C beta (PKCβ) inhibitor, for phase II trials. Secondary objectives were maximum-tolerated dose (MTD), pharmacokinetics (PK), toxicity, and response. Patients and Methods Patients at least 18 years of age with advanced cancer and an Eastern Cooperative Oncology Group performance status of 0 or 1 lower received enzastaurin orally once daily at a starting dose of 20 mg. Dose escalation proceeded using a modified Simon design. Results All 47 patients enrolled (mean age, 58 years) received at least one dose of enzastaurin, with a median of two cycles (range, one to 17 cycles). Prevalent malignancies were lung (n = 10) and head and neck cancers (n = 9). Although no MTD was identified up to 700 mg/d, 525 mg was chosen as the recommended dose, and 12 additional patients were accrued at that level. Three dose-limiting toxicities (QTc changes) occurred: one at the 700-mg dose (patient discontinued), and two in the expansion cohort at the 525-mg dose. Total analytes (enzastaurin and its metabolites) exposure increased with increasing doses up to 240 mg, and appeared to plateau at 525 and 700 mg. Grade 1 chromaturia, fatigue, and other GI toxicities were the most common, while no clinically significant grade 3/4 toxicities occurred. Two deaths, unrelated to enzastaurin, occurred. Twenty-one patients (45%) achieved stable disease (SD) for two to 16 cycles. Conclusion On the basis of plasma exposures and safety data, enzastaurin 525 mg once daily is the recommended phase II dose. Enzastaurin is well tolerated up to 700 mg/d. Evidence of early activity was seen with significant stable disease.

OBJECTIVES In this phase II study, the combination of docetaxel and exisulind (a GMP phosphodiesterase inhibitor) was given to patients with metastatic androgen independent prostate cancer (AIPC) to establish efficacy, assess toxicity, and determine pharmacokinetics of docetaxel administered alone and in combination with exisulind. METHODS Fourteen patients with metastatic AIPC were registered to receive weekly docetaxel for 4 weeks, followed by 2 weeks of rest; repeated up to a maximum of 6 cycles. Exisulind 250 mg was given orally twice a day starting on day 8 of the study and taken continuously. RESULTS All patients were evaluable for toxicity, response and survival. Grade 3 reversible toxicities included: fatigue, nausea, diarrhea, abdominal pain, rash, syncope, pulmonary edema, deep vein thrombosis, congestive heart failure, and elevations in transaminases, requiring therapy delays and/or dose reductions, or removal from therapy. Only 3 out of 14 patients (21.4%) had a 50% decline in prostate specific antigen (PSA) level that lasted > or =4 weeks; 1 out of 14 patients (7%) had a lymph node response. Median survival was 17.28 months. Docetaxel pharmacokinetics for 11 patients demonstrated mean +/- SD clearance values that were similar during week 1 and week 3 when exisulind had been added. CONCLUSIONS : Overall, our trial indicated that the toxicity profile and efficacy of this regimen is unlikely to be substantially better than single agent docetaxel.

Sunitinib is considered a first-line therapeutic option for patients with advanced clear cell renal cell carcinoma (ccRCC). Despite sunitinib's clinical efficacy, patients eventually develop drug resistance and disease progression. Herein, we tested the hypothesis whether initial sunitinib resistance may be transient and could be overcome by dose increase. In selected patients initially treated with 50 mg sunitinib and presenting with minimal toxicities, sunitinib dose was escalated to 62.5 mg and/or 75 mg at the time of tumor progression. Mice bearing two different patient-derived ccRCC xenografts (PDX) were treated 5 days per week with a dose-escalation schema (40–60–80 mg/kg sunitinib). Tumor tissues were collected before dose increments for immunohistochemistry analyses and drug levels. Selected intrapatient sunitinib dose escalation was safe and several patients had added progression-free survival. In parallel, our preclinical results showed that PDXs, although initially responsive to sunitinib at 40 mg/kg, eventually developed resistance. When the dose was incrementally increased, again we observed tumor response to sunitinib. A resistant phenotype was associated with transient increase of tumor vasculature despite intratumor sunitinib accumulation at higher dose. In addition, we observed associated changes in the expression of the methyltransferase EZH2 and histone marks at the time of resistance. Furthermore, specific EZH2 inhibition resulted in increased in vitro antitumor effect of sunitinib. Overall, our results suggest that initial sunitinib-induced resistance may be overcome, in part, by increasing the dose, and highlight the potential role of epigenetic changes associated with sunitinib resistance that can represent new targets for therapeutic intervention. Mol Cancer Ther; 14(2); 513–22. ©2014 AACR.

Purpose Patients with clinical stage I nonseminomatous germ cell tumors (NSGCTs) have been managed with surveillance, chemotherapy, or retroperitoneal lymphadenectomy (RPLND) with similar survival outcomes. Cost factors influencing the choice of therapy were evaluated using computer-based decision analysis. Methods A detailed model was developed that integrates projected costs for more than 60 possible treatment outcomes. It incorporates primary, adjuvant, and salvage chemotherapy, primary and postchemotherapy RPLND, and both laparoscopic and open surgical approaches. Starting values and probabilities were derived from a comprehensive meta-analysis of the last 25 years of testes cancer literature. Hypothesis testing was performed using sensitivity analysis. Results The model predicts a cost premium for both primary chemotherapy (18.7%) and RPLND (51.7%) compared with surveillance. If laparoscopic RPLND was practiced, the cost premium for primary surgery (29.1%) approached that of chemotherapy (26.4%). Open RPLND was 1.25× as costly as laparoscopic RPLND, primarily because of longer hospitalization. The choice of open RPLND yielded a 6.9% cost premium for a surveillance program in this model. For such a program, primary chemotherapy became cost advantageous when the probability of recurrence during surveillance was more than 46%. Conclusion This model allows a variety of treatment cost hypotheses to be tested. Primary RPLND is never cost advantageous over surveillance or primary chemotherapy. Surgical costs can significantly increase the overall cost of a surveillance program. In stage I patients with high-risk tumor characteristics, primary chemotherapy may have a cost advantage over surveillance.

Purpose: Histone deacetylase (HDAC) inhibitors have been shown to reverse epigenetic repression of certain genes, including retinoic acid receptor β2 (RARβ2). In this study, we examined whether RARβ2 expression is repressed in human renal cell carcinoma (RCC) and whether the HDAC inhibitor MS-275 may revert its epigenetic repression.Experimental Design: Six human tumor RCC cell lines were analyzed for RARβ2 gene expression and for methylation and acetylation status at the promoter level. Modulation of RARβ2 expression and correlation with antitumor activity by combination of MS-275 with 13-cis-retinoic acid (CRA) was assessed in a RARβ2-negative RCC cell line.Results: RARβ2 expression was either strongly present, weakly expressed, or absent in the RCC cell lines analyzed. Methylation-specific PCR indicated that the RARβ2 promoter was partially methylated in three of the cell lines. CRA treatment did not inhibit clonogenic growth in the RARβ2-negative cell line RCC1.18, whereas MS-275 induced a dose-dependent inhibitory effect. A greater inhibitory effect was observed with combination treatment (MS-275 + CRA). Treatment with MS-275 was associated with histone acetylation at the promoter level and synergistic gene reexpression of RARβ2 in combination with CRA. RARβ2 reexpression was associated with synergistic induction of the retinoid-responsive gene HOXA5. In vivo, single-agent CRA treatment showed no significant effect, whereas MS-275 and the combination induced a regression of RCC1.18 tumor xenografts. Discontinuation of treatment produced tumor recurrence in MS-275-treated mice, whereas animals treated with the combination remained tumor free.Conclusion: The HDAC inhibitor MS-275 seems to revert retinoid resistance due to epigenetic silencing of RARβ2 in a human RCC model and has greater antitumor activity in combination with CRA compared with single agents. Thus, the combination of HDAC inhibitors and retinoids may represent a novel therapeutic approach in patients with RCC.

99mTc-labeled bombesin analogues have shown promise for noninvasive detection of many tumors that express bombesin (BN)/gastrin-releasing peptide (GRP) receptors. 99mTc-labeled peptides, however, have a tendency to accumulate in the liver and intestines due to hepatobiliary clearance as a result of the lipophilicity of the 99mTc chelates. This makes the imaging of lesions in the abdominal area difficult. In this study, we have synthesized a new high affinity 99mTc-labeled BN analogue, [DTPA1, Lys3(99mTc-Pm-DADT), Tyr4]BN, having a built-in pharmacokinetic modifier, DTPA, and labeled with 99mTc using a hydrophilic diaminedithiol chelator (Pm-DADT) to effect low hepatobiliary clearance. In vitro binding studies using human prostate cancer PC-3 cell membranes showed that the inhibition constant (Ki) for [DTPA1, Lys3(99Tc-Pm-DADT), Tyr4]BN was 4.1 +/- 1.4 nM. Biodistribution studies of [DTPA1, Lys3(99mTc-Pm-DADT), Tyr4]BN in normal mice showed very low accumulation of radioactivity in the liver and intestines (1.32 +/- 0.13 and 4.58 +/- 0.50% ID, 4 h postinjection, respectively). There was significant uptake (7.71 +/- 1.37% ID/g, 1 h postinjection) in the pancreas which expresses BN/GRP receptors. The uptake in the pancreas could be blocked by BN, partially blocked by neuromedin B, but not affected by somatostatin, indicating that the in vivo binding was BN/GRP receptor specific. Scintigraphic images showed specific, high contrast delineation of prostate cancer PC-3 xenografts in SCID mice. Thus, the new peptide has a great potential for imaging BN/GRP receptor-positive cancers located even in the abdomen.

Purpose: Vascular endothelial growth factor (VEGF) promotes acute myelogenous leukemia (AML) cell growth and survival and may contribute to drug resistance. bevacizumab, an anti-VEGF monoclonal antibody, exhibits clinical activity against diverse malignancies when administered with cytotoxic chemotherapy. We conducted a Phase II clinical trial of bevacizumab administered after chemotherapy to adults with refractory or relapsed AML, using a timed sequential therapy (TST) approach. Experimental Design: bevacizumab 10 mg/kg was administered on day 8 after 1-β-d-arabinofuranosylcytosine 2 g/m2/72 h beginning day 1 and mitoxantrone 40 mg/m2 beginning day 4. In vivo laboratory correlates included AML cell VEGF receptor-1 (FLT-1) expression, marrow microvessel density, and free serum VEGF before and during TST with bevacizumab. Results: Forty-eight adults received induction therapy. Myelosuppression occurred in all of the patients similar to other TST regimens. Toxicities were decreased ejection fraction (6%), cerebrovascular bleed (4%), and mortality of 15%. Overall response was 23 of 48 (48%), with complete response (CR) in 16 (33%). Eighteen (14 CR and 4 partial response) underwent one consolidation cycle and 5 (3 CR and 2 partial response) underwent allogeneic transplant. Median overall and disease-free survivals for CR patients were 16.2 months (64%, 1 year) and 7 months (35%, 1 year). Marrow blasts demonstrated FLT-1 staining before bevacizumab and marked decrease in microvessel density after bevacizumab. VEGF was detected in pretreatment serum in 67% of patients tested, increased by day 8 in 52%, and decreased in 93% (67% undetectable) 2 h after bevacizumab. Conclusions: In this single arm study, cytotoxic chemotherapy followed by bevacizumab yields a favorable CR rate and duration in adults with AML that is resistant to traditional treatment approaches. The clearance of marrow blasts in some patients after bevacizumab suggests that VEGF neutralization might result directly in leukemic cell death. The potential biological and clinical activity of bevacizumab in AML warrants additional clinical and laboratory study.

Regulatory T cells (Tregs) represent a major obstacle of cancer immunotherapy. We reviewed here our discovery that Class I histone deacetylase (HDAC) inhibition can functionally target Tregs and help break the immune tolerance. We also discuss the effects of different classes of HDAC inhibitors on Tregs and the underline mechanisms, which may have a direct impact on designing cancer immunotherapy trials involving HDAC inhibitors.

VEGF pathway inhibitors have shown benefits in many cancers, yet many (often controversial) questions remain about whether vascular and tumor regrowth can occur when therapy is stopped. Marked increases in endothelial cell proliferation could play a role in putative rebounds, potentially influencing overall efficacy, dosing schedules, and presurgical intervention strategies. Clin Cancer Res; 18(14); 3719–21. ©2012 AACR.

Background: Cystine/glutamate exchanger xCT is a catalytic component of system xc- involved in transport of ‘conditionally indispensable’ amino acid cystine. Cystine transport is a rate limiting step for the synthesis of glutathione, a major intracellular redox regulator. Recently, we and other groups reported the overexpression of xCT and its association with drug resistance in several human cancers including bladder, glioma, breast, and colon. There are no studies to show the xCT expression in clear cell renal cell carcinoma (ccRCC) and its association with tyrosine kinase inhibitors resistance and metastasis. In the current study we have evaluated xCT expression in human ccRCC tumors arranged in tissue microarray (TMA) and determined its role in receptor tyrosine kinase inhibitor (RTKI) resistance and metastases using the patient derived tumor xenografts (PDX) models and TKI resistance ccRCC cells. Methods: Human Renal cell carcinoma tumor nephrectomy specimens arranged in tissue microarray (TMA) were used to determine xCT expression by immunohistochemistry. Patient derived tumor xenografts (PDX) of primary, metastasis, and sunitinib resistance were used to determine the role of xCT in RCC. To understand the molecular alterations associated with RTKI resistance, we have generated sunitinib resistance 786 OR ccRCC cells and performed RNAseq analysis. To determine the xCT inhibition effect on ccRCC tumor metastases, sulfasalazine, an inhibitor of xCT was used to treat metastatic ccRCC tumor xenografts transplanted in SCID mice. Results: Immunohistochemical evaluation of xCT in RCC TMA revealed that 70 % (19 out of 27) of the tumors express different levels of xCT. Association with tumor response to RTKI will be presented. RTKI less responsive PDX RP-R-02 was developed using the dose escalation treatment strategy and was found to have an upregulation of xCT when the tumors become less responsive to sunitinib. RNAseq analysis revealed differential gene expression of various pathway genes including lysosome biogenesis and function such as SLC7A11, HPS4, HPS5, CTSB, IFI30, PPT1, SCPEP1, TPP1, ATP6AP1L, MCOLN1, PRKAG2, and VPS18 in sunitinib resistant 786 OR cells compared to parental cells supports the role of lysosomes function in RTKI drug resistance. Furthermore, xCT inhibitor sulfasalazine treatment significantly decreased the metastasis lung nodules of RP-R-02LM in SCID mice demonstrated the xCT role in RCC tumor metastasis. Conclusions: We found preliminary evidence that overexpression of xCT may be associated with RTKI resistance in ccRCC. These results suggest that targeting the xCT in ccRCC may reverse the resistance and enhance the efficacy of RTKI. Additional studies using larger numbers of ccRCC tumors are required to identify xCT as a potential predictive biomarker for response/resistance to RTKI in ccRCC patients. Citation Format: Sreenivasulu Chintala, Remi Adelaiye-Ogala, Ashley Orillion, Sreevani Arisa, May Elbanna, Nur P. Damayanti, Roberto Pili. Association of xCT overexpression with RTKI resistance and metastases in clear cell renal cell 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 94. doi:10.1158/1538-7445.AM2017-94

Background: Our previous work showed a significant reduction of tumor growth, macrophage infiltration, circulating IGF-1, and mTOR activation with low protein diet in a patient derived xenograft model of prostate cancer. The evolutionarily conserved, nutrient sensing, mTOR pathway plays a central role in both development of advanced stage prostate cancer and immune responsiveness. This study presents novel data on the impact of dietary protein modification on the function of the host immune system in response to prostate cancer and immunotherapy. Methods: Our In vitro studies utilized bone marrow or tumor derived (RP-B6 Myc) macrophages. In vivo studies utilized the recently characterized RP-B6 Myc model. Mice were fed ad libitum control or methionine restricted diets for four weeks prior to S.C. implantation with ~1mm2 tumor pieces. Treatment of survivin peptide vaccine (1mg/ml S.C. 1 X week) and anti-PD-1 (20mg/kg I.P. 2 X week) began at ~50mm2 tumor size. Tumor volumes were blindly recorded 2 X week. End point analyses include: tumor weight, flow cytometric analysis, proteomic profiler analyses, and microbiome analyses from each diet and treatment group. Results: We show here that while methionine restriction (MR) has little impact on our RP-B6 Myc prostate cancer cell line, it does yield a significant alteration in both the polarization and function of M1 and M2 macrophages. In the in vitro MR conditions, we observed significantly enhanced polarization of M1 macrophages and reduced polarization of M2 macrophages. Functional analysis revealed increased tumoricidal activity of both M1, ‘antitumor’, and M2, ‘pro-tumor,’ macrophages suggesting a flip in M2 function from tumor-promoting to tumoricidal. Further analysis of the released cytokines in MR media conditions yielded significant increase of antitumor cytokines & chemokines, such as IL-12, IL-27, CXCL9, CXCL10, CXCL11, CCL2, CCL4, and TNF-alpha, a double-edged sword which in our system correlates with decreased cancer cell viability upon co-culture with amino acid restricted M1 and M2 macrophages. Our preliminary results show dietary MR yielding a significant inhibition of prostate cancer growth in the RP-B6-Myc model and our ongoing study with survivin peptide vaccine and anti-PD-1 immunotherapies will be available to present in the conference. Conclusions: Our data suggest that restricting methionine is sufficient to alter both the polarization and tumoricidal function of macrophages. Our preliminarily results show that restricted dietary methionine is able to inhibit prostate cancer growth, modify the host immune response and better inhibit prostate cancer growth alone or in combination with immunotherapy. These results provide a strong basis to consider diet restriction as a means to limit cancer growth targeting tumor immune system and potentially to enhance cancer patient responses to immunotherapy. Citation Format: Ashley R. Orillion, Sreenivasulu Chintala, Remi Adelaiye-Ogala, Li Shen, Nur Damayanti, May Elbanna, Sreevani Arisa, Bennett Elzey, Chinghai Kao, Luigi Fontana, Roberto Pili. Methionine restriction increases macrophage tumoricidal activity and significantly inhibits prostate cancer growth [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 250. doi:10.1158/1538-7445.AM2017-250

Background: Translocation Renal Cell Carcinoma (tRCC) represents an aggressive subtype of kidney cancer associated with various gene fusions involving translocation of one of two members of micropthalmia transcription factor (MiT) family, TFE3 or TFEB. Despite identification of multiple TFE3 gene fusions in tRCC, heterogeneous phenotype and various dysregulated signaling pathway resulting from variety of gene fusion partners pose a challenge to establish effective treatments for these patients. In this work, we sought to study the biology underlying oncogenesis in tRCC involving TFE3 fusion with genes associated with pre-mRNA splicing factor machinery; NONO, SFPQ and PRCC. Methods: To investigate the biology of different TFE3 fusion proteins, oncogenic phenotypes and oncogenic signaling were compared among cells with distinct endogenous expression of TFE3 fusions such as SFPQ-TFE3, NONO-TFE3, PRCC-TFE3. Endogenous SFPQ-TFE3 expressing cells, RP-RO7, were generated from patient derived xenograft. UOK-109 and UOK-146 (kindly provided by Dr. Marston Lenehan, NCI) were used as endogenous NONO-TFE3 and PRCC-TFE3 expressing cells, respectively. TFE3 fusion transcripts were identified with RT-PCR. TFE3 fusion preferential DNA binding was assessed with ChIP-sequencing. Oncogenic phenotype assessment was done in 2D culture and two different 3D models; 1) Solid tumor model, in which cancer cell interaction with extracellular matrix and stromal cells, were represented in multiculture-spheroid system, 2) Invasion model, in which cell ability to invade basement membrane barrier was modeled with matrix restricted spheroid. Results: Dissimilar oncogenic phenotypes were seen among RP-R07, UOK-109 and UOK-146 in 2D and 3D culture. The presence of nuclear E-Cadherin was observed in all three cells model, with increasing level of nuclear expression in fusion partner dependent manner (P Conclusions: Our results indicate a distinct biology underlying tRCC oncogenesis in different TFE3 fusion models involving kinase reprograming and nucleocytoplasmic shuttling regulation. These differences also suggest the possibility of generating personalized treatments targeting specific TFE3 fusion genes associated with the spliceosome machinery. Citation Format: Nur P. Damayanti, Sreenivasulu Chintala, Ashley Orillion, Remi Adelaiye-Ogala, May F. Elbanna, Pete Hollenhorst, Roberto Pili. Delineating translocation renal cell carcinoma oncogenesis in cells harboring TFE3 fusion with spliceosome machinery associated genes [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 4475. doi:10.1158/1538-7445.AM2017-4475

Background: Drug screening is a key component for drug development and optimizing anti-tumor therapies. Traditionally, in vitro drug testing has been conducted in monolayer systems that are not capable of recapitulating the tumor complexity. Recently, the field has witnessed the rise of interest in 3D culture systems which are capable of reproducing tumor complexity while circumventing the cost associated with in vivo drug testing. Our access to fresh patient samples has enabled us to establish a novel 3D culture system consisting of bladder cancer patient derived cell lines. Using a wide range of matrices and co-culture conditions with tumor associated stromal cells we were able to establish a unique high throughput drug testing tool. Methods: Matrigel and collagen based matrices were used to establish 3D culture systems of bladder cancer patient derived cells. Tumor cells were cultured in 3D conditions either alone or in coculture with tumor associated stromal cells. Response to Cisplatin and PI3K pathway targeted agents (i.e. LY LY3023414) was tested in both conditions. High throughput imaging via Thermo ArrayScan XTI was used to assess the biological behavior of spheroids as well as their response to therapies overtime. Confocal microscopy was used to validate the biological mimicry of tumor derived spheroids to the original patient tumors. Integration of RNA-seq data from the patient-derived tumor cells with the biological behavior and therapeutic response in 3D culture is ongoing for the purpose of characterizing the 3D model Results: In 3D culture conditions; bladder cancer derived cells were able to re-express E-cadherin that was suppressed upon propagation in monolayer. The re-expression of the epithelial marker (E-cadherin) observed in 3D accurately mirrors the original tumors; which are of epithelial origin. Phenotypic differences were observed across different matrix conditions and also among different tumor derived cells. Bladder 3D organoids of luminal origin were more sensitive to both cisplatin and PI3K pathway inhibitors as compared to those of basal origin. This drug response profile was reminiscent of what we observed in vivo using patient derived xenograft (PDX) models derived from the same tumors. The phenotypic as well as the drug response variations observed in our 3D culture correlated with variable gene expression profiles (luminal vs basal) that were detected in our RNA-seq data. Conclusion: As compared to monolayer, 3D culture is more capable of recapitulating tumor complexity and accurately reflects the drug resistance / sensitivity profiles that are observed in PDX models in vivo. Therefore, a 3D culture system provides an invaluable tool for high throughput screening of drugs in bladder cancer and providing a better understanding of tumor biology in the search of more effective treatments for bladder cancer patients. Citation Format: May Elbanna, Sreenivasulu Chintala, Eric Ciamporcero, Remi Adelayie, Ashley Orillion, Sreevani Arisa, Nur Damayanti, Michelle Grimard, TJ Puls, Sherry Harbin, Melissa Fishel, Roberto Pili. In vitro modeling of patient derived bladder cancer cell lines in 3D culture systems [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 5783. doi:10.1158/1538-7445.AM2017-5783

Background: Advanced renal cell carcinoma (RCC) responds initially to anti-angiogenic therapies but eventually develop resistance which may be driven by the expression of key intratumoral pro-survival protein and overall kinome reprogramming. Androgen receptor (AR) expression has been reported in clear cell renal cell carcinoma (ccRCC) but its biological role remains elusive and its association with resistance to tyrosine kinase inhibitors (TKIs) has not been studied. Here we report the role of AR and its association with resistance to TKIs in advanced RCC. Methods: Human RCC cell lines; 786-0, 786-0R (with induced sunitinib resistance), ACHN, URMC2 (with intrinsic sunitinib resistance) were used to assess the combination effect of sunitinib and the AR antagonist enzalutamide in vitro. In vivo studies utilizing 786-0 tumors assessed the combination effect of enzalutamide and sunitinib following acquired resistance to sunitinib. AR expression was detected by qRT-PCR and Western blot analysis, and AR localization by immunofluorescence in treated and non-treated cells. Gene array was used to assess 93 AR associated genes in sensitive and resistant cells. Results: Quantitative RT-PCR data revealed a significant increase in AR expression with sunitinib resistance (>100 folds; p>0.001). In vitro and in vivo studies indicated significant increase in nuclear and cytoplasmic expression of AR with sunitinib treatment in resistant cells which was abrogated with single agent enzalutamide and combination treatment. More interestingly, combination treatment of enzalutamide and sunitinib significantly decreased cell growth and induced tumor regression in vitro and in vivo, respectively. Conclusion: Our data suggest the role of AR both in intrinsic and acquired sunitinib resistance in ccRCC and provide a rationale for combination strategies to restore TKI sensitivity that can be tested in the clinical setting. Citation Format: Remi M. Adelaiye-Ogala, Sreenivasulu Chintala, Ashley Orillion, May Elbanna, Ben Elzey, Nur Damayanti, Kiersten M. Miles, Chinghai Kao, Piergiorgio Pettazzoni, Giulio F. Draetta, Roberto Pili. Targeting androgen receptor overcomes resistance to tyrosine kinase inhibitors in advanced clear cell renal cell 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 4170. doi:10.1158/1538-7445.AM2017-4170

2551 Background: Axitinib (AX) is a tyrosine kinase inhibitor (TKI) of vascular endothelial growth factor receptor (VEGFR) and a standard treatment for mRCC. Upregulation of mesenchymal-epithelial transition factor (c-MET) is implicated in resistance to VEGFR-directed therapy. An ongoing ph Ib study (NCT01999972) evaluated the safety and efficacy of AX + crizotinib (CZ), a TKI of c-MET, anaplastic lymphoma kinase (ALK), and ROS1. Methods: mRCC patients (pts) with advanced solid tumors were treated with AX + CZ in a dose escalation phase (DESC). After determining maximum tolerated dose (MTD) (modified toxicity probability interval), mRCC pts were enrolled into 2 cohorts in a dose expansion phase (DEXP). Cohort 1 (C1) was treatment-naïve and C2 had 1–2 prior therapies. The primary objectives were to assess the tolerability of AX + CZ, to obtain the MTD, and to select the recommended phase II dose. Results: As of Aug 5, 2016, 24 pts were screened and 22 pts treated in the DESC. Pts received AX 3 mg twice daily (BID) + CZ 200 mg BID (n = 5); AX 3 mg BID + CZ 250 mg BID (n = 3); AX 5 mg BID + CZ 200 mg BID (n = 4); or AX 5 mg BID + CZ 250 mg BID (n = 10) in a median 4 (range 1–23) cycles. There were no cycle 1 dose-limiting toxicities. One pt discontinued due to an AX-related alanine aminotransferase increase. Fifteen (68.2%) pts experienced Grade 3–4 adverse events (AEs), none in ≥2 pts; 1 pt had a Grade 5 AE (disease progression). AX 5 mg BID + CZ 250 mg BID was established as the MTD. Most frequent AEs in the MTD group were fatigue (70.0%), nausea (70.0%) and diarrhea (60.0%). In the ongoing DEXP, 15 pts have been treated at the MTD (n = 11 in C1, and 4 C2). Response evaluation (RECIST) is ongoing, with 1 complete response (CR), 3 partial responses (PR) and 4 stable disease (SD) in 10 pts in C1, and 1 PR and 2 SD in 4 pts in C2. Overall, 10 (66.7%) pts experienced Grade 3–4 AEs and 1 pt had a Grade 5 AE (disease progression). Most frequent AEs (≥60% pts) were nausea and diarrhea. Conclusions: We have identified AX 5 mg BID + CZ 250 mg BID as the MTD for combination therapy. This regimen has manageable toxicities and exhibits antitumor activity in treatment-naïve and pretreated mRCC. Further studies in VEGFR, c-MET, ALK and ROS1 tumor types are warranted. Clinical trial information: NCT01999972.

248 Background: Pulverized muscadine grape ( Vitis rotundifolia) skin (MPX) is a potential therapeutic option for men with biochemically recurrent (BCR) prostate cancer (PCa) wishing to defer androgen deprivation therapy. MPX demonstrated antitumor effects in PCa through antioxidant activity of its principal polyphenol components, ellagic acid, quercetin, and resveratrol. A Phase I trial demonstrated safety of MPX in doses up to 4000 mg/day. Methods: This is a 12-month, multi-center, placebo-controlled, two-dose, double-blinded trial of MPX (manufactured by Muscadine Naturals Inc. in Warsaw, NC) in 125 men with BCR PCa. Participants were stratified by baseline PSADT and Gleason score, with no restrictions for PSADT and no upper limit PSA value. Patients were randomly assigned 2:2:1 to receive 4000 mg (8 capsules) of MPX, 500 mg (1 capsule) of MPX plus 7 capsules of placebo, or 8 capsules of placebo. PSA levels were obtained every 3 months The trial was powered to detect a statistically significant between-group difference of around 6 months (low dose) and 12 months (high dose) in PSADT relative to placebo. Results: The intention to treat (ITT) population included 116 patients, of which 97% were treated for up to 6 and 58% were treated for up to 12 months. This ITT population was 79% white, with median age 68 years, 47% with Gleason score ≤ 6 or 3+4, and 12% with ECOG status of 1. Median PSADT in the ITT population lengthened from 7.5 months at baseline (range 1.4 to 74.6) to 9.8 months after treatment (range 2.3 to 151.5) (p < 0.001). There was no significant treatment difference in PSADT between the control and the treatment groups (p = 0.84). Eighteen percent (21/116) of men had a post-baseline PSADT of more than 200% of baseline. No clinically significant toxicities were seen. Conclusions: These data suggest that both 500 and 4000 mg of MPX are safe. The lengthening PSADT in patients treated with MPX is not significantly greater than that provided by placebo. A subgroup analysis of patients more likely to benefit (those with the AA genotype of MnSOD) is ongoing. Clinical trial information: NCT01317199.

The aim of this paper is to analyse and describe different conceptual models of successful ageing, active and healthy ageing developed in Europe and in America in the 20° century, starting from Rowe and Kahn's original model (1987, 1997).A narrative review was conducted on the literature on successful ageing.Our review included definition of successful ageing from European and American scholars. Models were found that aimed to describe indexes of active and healthy ageing, models devoted to describe processes involved in successful ageing, and additional views that emphasise subjective and objective perception of successful ageing. A description is also given of critiques on previous models and remedies according to Martin et al. (2014) and strategies for successful ageing according to Jeste and Depp (2014). The need is discussed for the enhancement of Rowe and Kahn's model and other models with a more inclusive, universal description of ageing, incorporating scientific evidence regarding active ageing.

Alternative pathways to the VEGF, such as hepatocyte growth factor or HGF/c-met, are emerging as key players in tumor angiogenesis and resistance to anti-VEGF therapies. The aim of this study was to assess the effects of a combination strategy targeting the VEGF and c-met pathways in clear cell renal cell carcinoma (ccRCC) models. Male SCID mice (8/group) were implanted with 786-O tumor pieces and treated with either a selective VEGF receptor tyrosine kinase inhibitor, axitinib (36 mg/kg, 2×/day); a c-met inhibitor, crizotinib (25 mg/kg, 1×/day); or combination. We further tested this drug combination in a human ccRCC patient–derived xenograft, RP-R-01, in both VEGF-targeted therapy-sensitive and -resistant models. To evaluate the resistant phenotype, we established an RP-R-01 sunitinib-resistant model by continuous sunitinib treatment (60 mg/kg, 1×/day) of RP-R-01–bearing mice. Treatment with single-agent crizotinib reduced tumor vascularization but failed to inhibit tumor growth in either model, despite also a significant increase of c-met expression and phosphorylation in the sunitinib-resistant tumors. In contrast, axitinib treatment was effective in inhibiting angiogenesis and tumor growth in both models, with its antitumor effect significantly increased by the combined treatment with crizotinib, independently from c-met expression. Combination treatment also induced prolonged survival and significant tumor growth inhibition in the 786-O human RCC model. Overall, our results support the rationale for the clinical testing of combined VEGF and HGF/c-met pathway blockade in the treatment of ccRCC, both in first- and second-line setting. Mol Cancer Ther; 14(1); 101–10. ©2014 AACR.

Background The Notch ligand Delta-like 4 (Dll4) is highly expressed in vascular endothelium and has been shown to play a pivotal role in regulating tumor angiogenesis. Blockade of the Dll4-Notch pathway in preclinical cancer models has been associated with non-productive angiogenesis and reduced tumor growth. Given the cross-talk between the vascular endothelial growth factor (VEGF) and Delta-Notch pathways in tumor angiogenesis, we examined the activity of a function-blocking Dll4 antibody, REGN1035, alone and in combination with anti-VEGF therapy in renal cell carcinoma (RCC). Methods and Results Severe combined immunodeficiency (SCID) mice bearing patient-derived clear cell RCC xenografts were treated with REGN1035 and in combination with the multi-targeted tyrosine kinase inhibitor sunitinib or the VEGF blocker ziv-aflibercept. Immunohistochemical and immunofluorescent analyses were carried out, as well as magnetic resonance imaging (MRI) examinations pre and 24 hours and 2 weeks post treatment. Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36–62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38–54%) and ziv-aflibercept (46%). Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72–80% growth inhibition), including some tumor regression. Magnetic resonance imaging showed a marked decrease in tumor perfusion in all treatment groups. Interestingly, anti-tumor efficacy of the combination of REGN1035 and ziv-aflibercept was also observed in a sunitinib resistant ccRCC model. Conclusions Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

Drug development and clinical decision making for patients with metastatic prostate cancer (PC) have been hindered by a lack of quantitative methods of assessing changes in bony disease burden that are associated with overall survival (OS). Bone scan index (BSI), a quantitative imaging biomarker of bone tumor burden, is prognostic in men with metastatic PC. We evaluated an automated method for BSI calculation for the association between BSI over time with clinical outcomes in a randomized double-blind trial of tasquinimod (TASQ) in men with metastatic castration-resistant PC (mCRPC).Bone scans collected during central review from the TASQ trial were analyzed retrospectively using EXINIbone(BSI), an automated software package for BSI calculation. Associations between BSI and other prognostic biomarkers, progression-free survival, OS, and treatment were evaluated over time.Of 201 men (57 TASQ and 28 placebo), 85 contributed scans at baseline and week 12 of sufficient quality. Baseline BSI correlated with prostate-specific antigen and alkaline phosphatase levels and was associated with OS in univariate (hazard ratio [HR] = 1.42, P = 0.013) and multivariate (HR = 1.64, P0.001) analyses. BSI worsening at 12 weeks was prognostic for progression-free survival (HR = 2.14 per BSI doubling, P0.001) and OS (HR = 1.58, P = 0.033) in multivariate analyses including baseline BSI and TASQ treatment. TASQ delayed BSI progression.BSI and BSI changes over time were independently associated with OS in men with mCRPC. A delay in objective radiographic bone scan progression with TASQ is suggested; prospective evaluation of BSI progression and response criteria in phase 3 trials of men with mCRPC is warranted.

One of the key challenges to improved testing of new experimental therapeutics in renal cell carcinoma (RCC) is the development of models that faithfully recapitulate early- and late-stage metastatic disease progression. Typical tumor implantation models utilize ectopic or orthotopic primary tumor implantation, but few include systemic spontaneous metastatic disease that mimics the clinical setting. This protocol describes the key steps to develop RCC disease progression stages similar to patients. First, it uses a highly metastatic mouse tumor cell line in a syngeneic model to show orthotopic tumor cell implantation. Methods include superficial and internal implantation into the sub-capsular space with cells combined with matrigel to prevent leakage and early spread. Next it describes the procedures for excision of tumor-bearing kidney (nephrectomy), with critical pre- and post- surgical mouse care. Finally, it outlines the steps necessary to monitor and assess micro-and macro-metastatic disease progression, including bioluminescent imaging as well provides a detailed visual necropsy guide to score systemic disease distribution. The goal of this protocol description is to facilitate the widespread use of clinically relevant metastatic RCC models to improve the predictive value of future therapeutic testing.

Castrate-resistant prostate cancer (CRPC) is a disease where survival is poor and treatment is challenging. Over the past 3 years, significant advances in the field have been made with US Food and Drug Administration approval of new drugs for patients with CRPC. However, despite the presence of new approved drugs such as enzalutamide, abiraterone, sipuleucel-T, cabazitaxel, and alpharadin, there is still an unmet need for novel agents with different mechanisms of action to target CRPC. Based on earlier studies demonstrating therapeutic potential of a quinoline-3-carboxamide agent roquinimex as an anticancer drug, efforts were directed to identify other useful members in this class. Tasquinimod is a second-generation quinoline-3-carboxamide agent that is currently in final stages of clinical development as a treatment for CRPC. The preclinical studies of tasquinimod have formed the basis for its success as an antiangiogenic and immunomodulatory agent in this disease. Tasquinimod is an orally available agent that has shown efficacy and favorable safety profile as deduced by the results of Phase I and II clinical trials of this drug in prostate cancer. The place of tasquinimod in the treatment of CRPC patients is currently under examination in an ongoing Phase III clinical trial. In this review, we will discuss tasquinimod, starting from its discovery and current knowledge on potential mechanisms of action to its clinical potential in CRPC.

Castration resistant prostate cancer (CRPC) remains a therapeutic challenge despite recent therapeutic advances. Epigenetic mechanisms, including DNA methylation, histone modifications, and microRNA (miRs), have been associated with the biology of CRPC and have been identified as potential targets for therapeutic interventions. Rapid development of inhibitors towards these epigenetic targets has given rise to promising novel therapeutic opportunities in cancer, including CRPC. The preclinical data on the role of histone deacetylases, methyltransferases, demethylases, and miRs in CRPC offer a scenario for potential clinical success of epigenetic therapies in rational combination strategies. The identification of predictors of response to agents targeting histone modifications will be critical to identify the CRPC patients who are most suitable for this therapeutic approach.

First line treatment of patients with castrate resistant prostate cancer (CRPC) primarily involves administration of docetaxel chemotherapy. Unfortunately, resistance to docetaxel therapy is an ultimate occurrence. Alterations in androgen receptor (AR) expression and signaling are associated mechanisms underlying resistance to docetaxel treatment in CRPC. Heat shock protein 90 (Hsp90) is a molecular chaperone, which regulates the activation, maturation and stability of critical signaling proteins involved in prostate cancer, including the AR. This knowledge and recent advances in compound design and development have highlighted Hsp90 as an attractive therapeutic target for the treatment of CRPC. We recently reported the development of a MYC-CaP castrate resistant (MYC-CaP/CR) transplant tumor model, which expresses amplified wild type AR. Within, we report that a second generation Hsp90 inhibitor, NVP-AUY922, inhibits cell growth and significantly induces cell death in MYC-CaP/CR and Pten-CaP/cE2 cell lines. NVP-AUY922 induced proteasome degradation of AR, though interestingly does not require loss of AR protein to inhibit AR transcriptional activity. Further, NVP-AUY922 increased docetaxel toxicity in MYC-CaP/CR and Pten-CaP/cE2 cell lines in vitro. Finally, NVP-AUY922/docetaxel combination therapy in mice bearing MYC-CaP/CR tumors resulted in greater anti-tumor activity compared to single treatment. This study demonstrates that NVP-AUY922 elicits potent activity towards AR signaling and augments chemotherapy response in a mouse model of CRPC, providing rationale for the continued clinical development of Hsp90 inhibitors in clinical trials for treatment of CRPC patients.

Obesity, smoking, hypertension, and diabetes are risk factors for renal cell carcinoma development. Their presence has been associated with a worse outcome in various cancers. We sought to determine their association with outcome of sunitinib treatment in metastatic renal cell carcinoma (mRCC).An international multicenter retrospective study of sunitinib-treated mRCC patients was performed. Multivariate analyses were performed to determine the association between outcome and the pretreatment status of smoking, body mass index, hypertension, diabetes, and other known prognostic factors.Between 2004 and 2013, 278 mRCC patients were treated with sunitinib: 59 were active smokers, 67 were obese, 73 were diabetic, and 165 had pretreatment hypertension. Median progression-free survival (PFS) was 9 months, and overall survival (OS) was 22 months. Factors associated with PFS were smoking status (past and active smokers: hazard ratio [HR]: 1.17, p = .39; never smokers: HR: 2.94, p.0001), non-clear cell histology (HR: 1.62, p = .011), pretreatment neutrophil-to-lymphocyte ratio3 (HR: 3.51, p.0001), use of angiotensin system inhibitors (HR: 0.63, p = .01), sunitinib dose reduction or treatment interruption (HR: 0.72, p = .045), and Heng risk (good and intermediate risk: HR: 1.07, p = .77; poor risk: HR: 1.87, p = .046). Factors associated with OS were smoking status (past and active smokers: HR: 1.25, p = .29; never smokers: HR: 2.7, p.0001), pretreatment neutrophil-to-lymphocyte ratio3 (HR: 2.95, p.0001), and sunitinib-induced hypertension (HR: 0.57, p = .002).Active smoking may negatively affect the PFS and OS of sunitinib-treated mRCC. Clinicians should consider advising patients to quit smoking at initiation of sunitinib treatment for mRCC.

Purpose: Tasquinimod (Active Biotech) is an oral immunomodulatory, anti-angiogenic, and anti-metastatic agent that delayed metastatic disease progression in a randomized placebo-controlled phase II trial in men with metastatic castration-resistant prostate cancer (mCRPC). Here, we report long-term survival with biomarker correlates from this trial. Experimental Design: Two hundred and one (134 tasquinimod and 67 placebo) men with mCRPC were evaluated. Forty-one men randomized to placebo crossed over to tasquinimod. Survival data were collected with a median follow-up time of 37 months. Exploratory biomarker studies at baseline and over time were collected to evaluate potential mechanism-based correlates with tasquinimod efficacy including progression-free survival (PFS) and overall survival (OS). Results: With 111 mortality events, median OS was 33.4 months for tasquinimod versus 30.4 months for placebo overall, and 34.2 versus 27.1 months in men with bone metastases (n = 136), respectively. Multivariable analysis demonstrated an adjusted HR of 0.52 [95% confidence interval (CI), 0.35–0.78; P = 0.001] for PFS and 0.64 (95% CI, 0.42–0.97; P = 0.034) for OS, favoring tasquinimod. Time-to-symptomatic progression was improved with tasquinimod (P = 0.039, HR = 0.42). Toxicities tended to be mild in nature and improved over time. Biomarker analyses suggested a favorable impact on bone alkaline phosphatase and lactate dehydrogenase (LDH) over time and a transient induction of inflammatory biomarkers, VEGF-A, and thrombospondin-1 levels with tasquinimod. Baseline levels of thrombospondin-1 less than the median were predictive of treatment benefit. Conclusions: The survival observed in this trial of men with minimally symptomatic mCRPC suggests that the prolongation in PFS with tasquinimod may lead to a survival advantage in this setting, particularly among men with skeletal metastases, and has a favorable risk:benefit ratio. Clin Cancer Res; 19(24); 6891–901. ©2013 AACR.

Prostate cancer is the most common noncutaneous cancer among men. This case report describes a 43-year-old man with rapidly progressing castration-resistant prostate cancer (CRPC) that responded initially to docetaxel and did not tolerate cabazitaxel. He subsequently received a third line of chemotherapy with cyclophosphamide and prednisone, and experienced a dramatic clinical and radiographic response in his liver metastases. This therapeutic intervention led to a significant clinical benefit and confirms the potential use of cyclophosphamide in patients with CRPC, particularly those with liver metastases.

In 2012, an estimated 64,770 men and women were diagnosed with malignancy of the kidney and renal pelvis, of which 13,570 succumbed to their disease. Common genetic aberrations in renal cell carcinomas (RCCs) include loss of function of the VHL gene in clear-cell RCC, overexpression of the c-MET gene in papillary RCC type I, deficiency in the FH gene in papillary RCC type II and loss of heterozygozity of the BHD gene in chromophobe RCC. Recent studies illustrate epigenetic silencing of VHL, as well as alterations in histone modifications and their governing enzymes. The possibility of reversing these epigenetic marks has resulted in efforts to target these changes by utilizing inhibitors of HDACs, DNA methyltransferases and, recently, histone methyltransferases in preclinical and clinical studies. This article focuses on potential therapeutic interventions, and the implications of histone modifications and related enzyme alterations in RCC.

Recent investigations of renal cell carcinoma (RCC) have revealed several epigenetic modifications, as well as alterations in the gene and enzymes that regulate these changes. Preclinical models have revealed that histone gene modifiers and epigenetic alterations may play a critical role in RCC tumorigenesis. Specific changes in DNA methylation and mutations of histone modifiers have been identified and may be associated with an aggressive phenotype. In addition, the potential of reversing the effects of these enzymes, and hence reversing the cellular epigenetic landscape to a “normal phenotype” has led to an increasing interest in developing targeted chromatin remodeling agents. However, the translation of the understanding of these changes to the clinic for the treatment of RCC has posed significant challenges, also as consequence from tumor heterogeneity. This review describes the aberrant histone and DNA alterations recently reported in RCC and highlight the potential targeted chromatin remodeling therapies in the management of this disease.

Abstract To evaluate the concept that localized delivery of angiogenic factors via virus-mediated gene transfer may be useful in the treatment of ischemic disorders, the replication-deficient adenovirus (Ad) vector AdCMV.VEGF 165 (where CMV is cytomegalovirus and VEGF is vascular endothelial growth factor) containing the cDNA for human VEGF 165 , a secreted endothelial cell–specific angiogenic growth factor, was constructed. Human umbilical vein endothelial cells (HUVECs) and rat aorta smooth muscle cells (RASMCs) infected with AdCMV.VEGF 165 (5 and 20 plaque-forming units [pfu] per cell) demonstrated VEGF mRNA expression and protein secretion into the supernatant. Furthermore, the conditioned medium from these cells enhanced vascular permeability in vivo. In contrast, neither VEGF mRNA nor secreted protein was found in uninfected HUVECs or RASMCs or in cells infected with the control vector AdCMV.βgal (where βgal is β-galactosidase). Assessment of starved HUVECs at 14 days demonstrated sixfold more cells for AdCMV.VEGF 165 -infected HUVECs (20 pfu per cell) than for either infected or uninfected control cells. RASMC proliferation was unaffected by infection with AdCMV.VEGF 165 . When plated in 2% serum on dishes precoated with reconstituted basement membrane (Matrigel), HUVECs infected with AdCMV.VEGF 165 (20 pfu per cell) differentiated into capillary-like structures. Under similar conditions, both uninfected HUVECs and HUVECs infected with AdCMV.βgal did not differentiate. To evaluate the ability of AdCMV.VEGF 165 to function in vivo, either AdCMV. VEGF 165 or AdCMV.βgal (2×10 10 pfu) was resuspended in 0.5 mL Matrigel and injected subcutaneously into mice. Immunohistochemical staining demonstrated VEGF in the tissues surrounding the Matrigel plugs containing AdCMV.VEGF 165 up to 3 weeks after injection, whereas no VEGF was found in the control plugs with AdCMV.βgal. Two weeks after injection, there was histological evidence of neovascularization in the tissues surrounding the Matrigel containing AdCMV.VEGF 165 , whereas no significant angiogenesis was observed in response to AdCMV.βgal. Furthermore, the Matrigel plugs with AdCMV.VEGF 165 demonstrated hemoglobin content fourfold higher than the plugs with AdCMV.βgal. Together, these in vitro and in vivo studies are consistent with the concept that Ad vectors may provide a useful strategy for efficient local delivery of VEGF 165 in the treatment of ischemic diseases.

In vivo gene transfer of angiogenic growth factors represents a potential approach to the treatment of ischemic diseases. The present study examined the in vitro and in vivo effects of two replication-deficient recombinant adenovirus (Ad) vectors coding for human acidic fibroblast growth factor (aFGF1-154). One vector codes for the nonsecreted form of the peptide (AdCMV.aFGF1-154), and the other vector codes for a recombinant, secreted form (AdCMV.sp+aFGF1-154). AdCMV.NLS beta gal, an adenovirus vector coding for beta-galactosidase (beta-Gal), was used as a control. Assessment of proliferation of starved human umbilical vein endothelial cells infected with AdCMV.aFGF1-154 and AdCMV.sp+aFGF1-154 (20 pfu/cell) showed approximately 6- and 10-fold increase in cell number over control, respectively. Infection with AdCMV.sp+aFGF1-154 and with AdCMV.aFGF1-154 enhanced endothelial cell differentiation into capillary-like structures in vitro. However, this effect was significantly more pronounced with AdCMV.sp+aFGF1-154 than with AdCMV.aFGF1-154. Angiogenesis in vivo was assessed by injecting subcutaneously into mice 750 microliters of reconstituted basement membrane proteins (Matrigel) and the Ad vectors (2 x 10(8) pfu). After 14 days, there was histologic evidence of neovascularization in the animal's tissue surrounding the Matrigel plugs with AdCMV.aFGF1-154 and AdCMV.sp+aFGF1-154. Further, the hemoglobin content of the Matrigel plugs with AdCMV.aFGF1-154 and with AdCMV.sp+aFGF1-154 was, respectively, 2.3- and 2.6-fold higher than with AdCMV.NLS beta gal. Together, these observations support the concept that adenovirus vectors coding for various forms of acidic FGF1-154 may be used to induce angiogenesis in vivo and may provide a new therapeutic approach to ischemic diseases.

Background: Recent advances in immunotherapy have highlighted the antitumor effects of immune checkpoint inhibition. Novel anti-PD-1/PD-L1 immunotherapies have been shown to effectively overcome tumor avoidance of immune surveillance in several tumor types including renal cell carcinoma. Our group has recently shown that the selective class I HDAC inhibitor entinostat is effective in suppressing regulatory T cells and enhancing immunotherapies in murine renal and prostate models, RENCA and Myc-Cap respectively. In this study we have evaluated the combination of entinostat with an anti-PD-1 antibody in the RENCA renal cell carcinoma model. Methods: 32 BALB/c female mice were implanted with the syngenic, orthotopic, renal cell carcinoma mouse model, RENCA - luciferase tagged - at day -8. Treatment (8 mice /group) with anti-mouse-PD-1 (aPD-1; 10mg/kg twice a week, I.P.), entinostat (5mg/kg 5 days a week), or combination of the two was begun at day 1. Bioluminescence imaging was performed at days -1, 9 and 19 to assess the orthotopic tumor growth. End point tumor weights were taken to assess the effect of combination treatment. Results: Analysis of tumor growth showed a reduction of bioluminescence across the three time points in the combination group as compared to the vehicle and single agent treatments. Additionally, end point analysis of tumor weights revealed an overall reduction in the size of the tumors in the entinostat/anti-mPD-1 combination group (88% inhibition) as compared to the vehicle (p = 0.0002), aPD-1 alone (25% inhibition)(p = 0.0181), and entinostat alone (63% inhibition)(p = 0.0481) groups. Examination of the status of the infiltrating immune cells of the tumor microenvironment via flow cytometry, qRT-PCR, immunohistochemistry, and/or immunofluorescence analysis is ongoing. Conclusions: Our preliminary results suggest that the immunomodulatory activity of the selective class I HDAC inhibitor entinostat may enhance the antitumor effect of PD-1/PD-L1 inhibition and provide the rationale for the clinical testing of this novel combination in patients with RCC. Citation Format: Ashley R. Orillion, Li Shen, Remi Adelaiye-Ogala, May Elbanna, Sreenivasulu Chintala, Sreevani Arisa, Roberto Pili. The selective class I HDAC inhibitor entinostat enhances the antitumor effect of PD-1 inhibition in a syngeneic orthotopic murine model of renal cell carcinoma. [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 4906.

Background: MicroRNA 605 (miR-605) has been recently reported as a putative tumor suppressor and its overexpression decreases tumor cell proliferation, migration and clonogenicity. To date, the role of miR-605 in renal cell carcinoma (RCC) has not been investigated. We recently showed the decrease of circulating miR-605 in serum of clear cell renal cell carcinoma (ccRCC) patients who responded to the treatment with the histone deacetylase (HDAC) inhibitor vorinostat, and the VEGF blocker bevacizumab. The current study was designed to investigate the expression of miR-605 and understand the mechanism(s) responsible the extracellular release of miR-605 using RCC cells. Methods: 786-0 cells were treated with and without vorinostat for 24h and condition media were collected, briefly centrifuged to settle the cells and debris, and processed to isolate exosomes using the ExoQuick exosome isolation kit (Systems Biology, CA). Purified exosomes and 786-0 cells were used to isolate RNA and further prepared cDNA to utilize for quantitative RT-PCR analysis. Expression of miR-605 in exosomes and cells was determined by Quantitative RT-PCR using TaqMan MicroRNA Assays with miR-605 primers obtained from Applied Biosystems, NY. To determine the role of secretory protein 24 family member D (SEC24D), a catalytic component of coat protein complex (COPII) involved in the secretory pathway, 786-0 cells treated with vorinostat were used to determine SEC24D expression by QRT-PCR and Western blot analysis. TCGA data was used to determine correlation of SEC24D expression clear cell renal cell carcinoma patients’ survival. Results: Vorinostat treatment resulted in a significant decrease of miR-605 expression in exosomes and increase (100 fold) of intracellular expression. Furthermore, the increased intracellular miR-605 was associated with the inhibition of SEC24D mRNA and protein expression in 786-0 cells treated with vorinostat. Cancer Genomic data analysis of c-Bioportal from MSKCC of TCGA revealed the overall poor survival of ccRCC patients with alteration of SEC24D. Conclusion: Taken together, our preliminary data suggest that the HDAC inhibitor vorinostat inhibits SEC24D and exosome mediated extracellular secretion of miR-605 in RCC cells. These results suggest that vorinostat treatment retained intracellular miR-605 that target genes involved in cell survival and proliferation in RCC. Further studies will evaluate circulating miR-605 as a predictive biomarker to determine the efficacy of vorinostat in ongoing trials with RCC patients. Citation Format: Sreenivasulu Chintala, Remi Adelaiye-Ogala, Ashley Orillion, Sreevani Arisa, May Elbanna, Roberto Pili. Inhibition of SEC24D decreases exosome release of the tumor suppressor miR-605 in renal cell carcinoma. [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 955.

Background: PI3K pathway has been reported to be deregulated in up to 30% of bladder cancer patients. We have recently established two patient derived xenografts (PDX) models in our lab that carry unique helical domain mutations in the PIK3CA gene that is known to be deregulated in bladder cancer. This sets our models as unique tools for understanding the molecular background that would dictate an optimal response to targeting the PI3K pathway in vivo as well as the potential mechanisms of resistance. Methods: RNA-seq was carried out to understand the molecular make up of our PDX models (RP-B-01 and RP-B-02) and to identify clinically relevant drug targets. In-vivo drug testing was done using a dual PI3K-mTOR inhibitor to test the response to this class of drugs. Cell lines derived from the PDX models were used for in-vitro studies to validate our in-vivo data and to calculate the IC-50 for this class of agents in our cell lines. Western blot was used to assess the molecular effects of these agents using both in-vivo specimens as well as cell lines that were treated in vitro. Results: Our RNA-seq data have shown that our models (RP-B-01 and RP-B-02) are molecularly distinct where RP-B-01 has a basal-like phenotype while RP-B-02 is has a luminal like phenotype. Additionally, these models carry two unique helical domain mutations in the PIK3CA gene (E542K and E545K mutations respectively). Despite the molecular similarity between these two mutations, the two models responded differently to a dual PI3K-mTOR inhibiter in vivo. The RP-B-02 tumor model significantly responded to the drug compared to vehicle treated mice (P Value = 0.03) while the RP-B-01 model was resistant. Cell lines derived from these models were able to recapitulate the same phenotype in-vitro and IC-50 for each cell line was significantly different (IC50 for RP-B-01 cells = 204.1 nM; IC50 for RP-B-02 cells = 73.21 nM). Western blot analysis has shown that despite the ability of the dual PI3K-mTOR inhibitor to hit the target in RP-B-02 PDX, the treatment was not able to have the same biological effect in the other model (RP-B-01). Interestingly, supplementing media with insulin and nutrients switched the response phenotype and rendered cells derived from the RP-B-02 model more resistant to the PI3K-mTOR inhibitor. Conclusion: Response to PI3K pathway inhibitors in bladder cancer is not only dictated by the presence of targetable mutations but more importantly by the molecular make up of individual tumors which should be taken into account when using these agents in the clinic. Citation Format: May F. Elbanna, Eric Ciamporcero, Remi Adelaiye, Ashley Orillion, Sreenivasulu Chintala, Roberto Pili. Differential response to a dual PI3K/mTOR inhibitor in PIK3CA mutant urothelial cancer patient derived xenografts. [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 384.

Background: Immunosuppressive factors such as regulatory T cells (Tregs) and myeloid-derived suppressive cells (MDSCs) limit the efficacy of immunotherapies. Histone deacetylase (HDAC) inhibitors have been shown to have immunomodulatory effects. We have previously reported that the class I selective HDAC inhibitor entinostat has synergistic antitumor effects in combination with high dose interleukin-2 (IL-2) in a renal cell carcinoma model by down-regulating Foxp3 expression and function of Tregs. Thus, we have conducted a phase I/II clinical study with entinostat and high dose IL-2 in patients (pts) with metastatic clear cell renal cell carcinoma. Methods: The primary objectives were to evaluate the safety, tolerability and efficacy of this combination strategy. The main eligibility criteria were clear cell histology, no prior treatments, and being fit to receive high dose IL-2. The phase I portion consisted of two dose levels of entinostat (3 and 5 mg, PO every14 days) and a fixed standard dose of IL-2 (600,000 units/kg IV every 8 hrs, up to 14 doses). Each cycle was 85 days. To test our hypothesis, the fixed sample size for the phase II was 36 with a type I/II error of 10%. If 11 or more of the pts have a response, the hypothesis that the response rate is ? 20% is rejected. Results: Dose levels 1 and 2 were completed without DLTs and 5 mg was the recommended phase II dose for entinostat. The most common transient grade 3/4 toxicities were hypophosphatemia (16%), lymphopenia (15%), and hypocalcemia (7%). We have enrolled a total of 47 pts (44 at dose level 2), and 37 have completed one cycle (84 days) treatment. Four pts were not evaluable and were replaced. To date, the objective response is 35% (10 PR, 3 CR), the median progression-free survival is 16.1 months (6.2,27.8) and the median overall survival is 65.3 months (52.6,65.3). Decreased Tregs have been observed following treatment and lower numbers were associated with response. Analysis of monocityc MDSCs and activated antigen presenting cells will be also reported. Conclusions: The results from this clinical trial suggest that entinostat may increase the therapeutic effect of high dose IL-2 by modulating immunosuppressive cells, and represent the first example of how epigenetic agents may be rationally combined with immunotherapies. (R21CA137649; U01CA70095) Citation Format: Roberto Pili, David I. Quinn, Hans J. Hammers, J. Paul Monk, Saby George, Tanya B. Dorff, Thomas Olencki, Li Shen, Dominick Lamonica, Alan Hutson, Adrienne Groman, Susan M. Perkins, Richard Piekarz, Michael Carducci. Results from a phase I/II study with the HDAC inhibitor entinostat in combination with high-dose interleukin-2 in renal cell carcinoma patients (CTEP#7870). [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 CT015.

Background: Epidemiological studies link prostate cancer (CaP) to dietary intake. Recent research has shown that individuals consuming a Western diet, high in protein, have higher circulating IGF-1 (insulin-like growth factor 1) which feeds into the nutrient sensing mTOR pathway. This evolutionarily conserved pathway is central to the development of advanced stage and castration resistant CaP. Our previous published studies have shown that dietary protein restriction inhibits tumor growth via mTOR pathway alteration and reduces circulating IGF-1 levels in vivo. The current study hypothesizes that dietary methionine restriction will alter the functionality of immune cells enhancing the ability of the immune system to respond to cancerous insults. Methods: Mice were fed low (7% protein) or control protein (21% protein) diets. In a prevention study mice consumed modified diets for four weeks prior to being inoculated with CaP tumors. In a simultaneous intervention study mice were inoculated with CaP tumors first then four weeks later were placed on the modified diets. Results: In the low protein diet group, we observed that pro-tumor M2 polarized macrophages were significantly reduced in the tumor microenvironment (TME) for both prevention (p = 0.012) and intervention diet (p = 0.0003) studies as compared to the control diet, in addition to observation of mTOR inhibition and IGF-1 reduction. Besides protein content in diet, we also analyzed the amino acid composition. Multiple groups have shown that methionine restriction (MR) inhibits mTOR activation, alters the immune system, and prolongs the survival of rodents. The mechanism by which MR impacts the innate immune system is still poorly understood. In our preliminary in vitro studies, we observed that modification of a single amino acid (AA), such as methionine, is sufficient to inhibit activation of both the mTOR pathway and M2 polarization (Arginase1 qRT-PCR of two samples in quadruplicate (p = 0.0732)), while increasing the presence of M1 macrophage marker iNOS (p = 0.2689) in bone marrow derived macrophages (BMDMs). Thus, we hypothesize that modulating specific amino acids in the diet is sufficient to alter macrophage expression of M1/M2 characteristics, and their functions in the TME. Conclusions: Preliminarily data shows that altering one specific AA intricately linked to the mTOR pathway is sufficient to change macrophage polarization status both at the protein and gene expression levels, suggesting that dietary alteration of a single AA is capable of altering macrophage function. The results of the study provide the basis for translational use of dietary means to alter the immune system and improve the therapeutic effects of immunotherapies. Citation Format: Ashley Orillion, Remi Adelaiye-Ogala, Li Shen, Eric Ciamporcero, May Elbanna, Sreenivasulu Chintala, Sreevani Arisa, Ben Elzey, Chinghai Kao, Luigi Fontana, Roberto Pili. Methionine restriction alters functional polarization of macrophages in a murine model of prostate 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 897.

TPS4581Background: Novel strategies to enhance the activity of immune-checkpoint inhibitors are under development. Our group has reported that the HDAC inhibitor entinostat suppresses regulatory T ...

5065Background: Considerable evidence indicates that exposure of tumor cells to high concentrations of 1,25(OH)2 vitamin D3 [1,25D3] in vitro can suppress in vivo tumor growth. Several studies have...

500 Background: Immunosuppressive factors such as regulatory T cells (Tregs) and myeloid-derived suppressive cells (MDSCs) limit the efficacy of immunotherapies. Histone deacetylase (HDAC) inhibitors have been shown to have immunomodulatory effects. We have previously reported that the class I HDAC inhibitor entinostat has synergistic antitumor effects in combination with high dose interleukin-2 (IL-2) in a renal cell carcinoma model by down-regulating Foxp3 expression and function of Tregs. Thus, we have conducted a Phase I/II clinical study with entinostat and high dose IL-2 in patients (pts) with metastatic clear cell renal cell carcinoma. Methods: The primary objectives were to evaluate the safety, tolerability and efficacy of this combination strategy. The main eligibility criteria were clear cell histology and being fit to receive high dose IL-2. The phase I portion consisted of two dose levels of entinostat (3 and 5 mg, PO every14 days) and a fixed dose of IL-2 (600,000 units/kg every 8 hrs). To test our hypothesis, the fixed sample size at the Phase II dose level was 36 with a type I/II error of 10%. If 11 or more of the pts have a response, the hypothesis that the response rate is ≤ 20% is rejected. Results: Dose levels 1 and 2 were completed without DLTs and 5 mg entinostat was the Phase II recommended dose. No severe adverse events were observed during the first 45 days of treatment. The most common transient grade 3/4 toxicities were lymphopenia (50%), neutropenia (9%), and hypophosphatemia (6%). To date, we have enrolled 39 pts at dose level 2, and 35 have completed one cycle (84 days). Four pts were not evaluable. Twelve pts have achieved objective response (39%; 9 PR, 3 CR) with a median time to response of 81 days (55-96). The median PFS has not been reached with a median follow-up of 437 days (30-1428). Preliminary results show decreased Tregs and monocytic MDSCs following treatment and suggest an association of increased CD14+/CD86+ and CD14+HLADR+cells with objective response. Conclusions: The results from this phase I/II suggest that entinostat may increase the therapeutic effect of high dose IL-2 by modulating immunosuppressive cells (R21CA137649; U01CA70095). Clinical trial information: NCT01038778.