Targeting hyaluronic acid synthase-3 (HAS3) for the treatment of advanced renal cell carcinoma

BACKGROUND

Hyaluronic acid (HA) promotes cancer metastasis; however, the currently approved treatments do not target HA. Metastatic renal carcinoma (mRCC) is an incurable disease. Sorafenib (SF) is a modestly effective antiangiogenic drug for mRCC. Although only endothelial cells express known SF targets, SF is cytotoxic to RCC cells at concentrations higher than the pharmacological-dose (5-µM). Using patient cohorts, mRCC models, and SF combination with 4-methylumbelliferone (MU), we discovered an SF target in RCC cells and targeted it for treatment.

METHODS

We analyzed HA-synthase (HAS1, HAS2, HAS3) expression in RCC cells and clinical (n = 129), TCGA-KIRC (n = 542), and TCGA-KIRP (n = 291) cohorts. We evaluated the efficacy of SF and SF plus MU combination in RCC cells, HAS3-transfectants, endothelial-RCC co-cultures, and xenografts.

RESULTS

RCC cells showed increased HAS3 expression. In the clinical and TCGA-KIRC/TCGA-KIRP cohorts, higher HAS3 levels predicted metastasis and shorter survival. At > 10-µM dose, SF inhibited HAS3/HA-synthesis and RCC cell growth. However, at ≤ 5-µM dose SF in combination with MU inhibited HAS3/HA synthesis, growth of RCC cells and endothelial-RCC co-cultures, and induced apoptosis. The combination inhibited motility/invasion and an HA-signaling-related invasive-signature. We previously showed that MU inhibits SF inactivation in RCC cells. While HAS3-knockdown transfectants were sensitive to SF, ectopic-HAS3-expression induced resistance to the combination. In RCC models, the combination inhibited tumor growth and metastasis with little toxicity; however, ectopic-HAS3-expressing tumors were resistant.

CONCLUSION

HAS3 is the first known target of SF in RCC cells. In combination with MU (human equivalent-dose, 0.6-1.1-g/day), SF targets HAS3 and effectively abrogates mRCC.

Molecular Oncology of Bladder Cancer from Inception to Modern Perspective

Within the last forty years, seminal contributions have been made in the areas of bladder cancer (BC) biology, driver genes, molecular profiling, biomarkers, and therapeutic targets for improving personalized patient care. This overview includes seminal discoveries and advances in the molecular oncology of BC. Starting with the concept of divergent molecular pathways for the development of low- and high-grade bladder tumors, field cancerization versus clonality of bladder tumors, cancer driver genes/mutations, genetic polymorphisms, and bacillus Calmette-Guérin (BCG) as an early form of immunotherapy are some of the conceptual contributions towards improving patient care. Although beginning with a promise of predicting prognosis and individualizing treatments, "-omic" approaches and molecular subtypes have revealed the importance of BC stem cells, lineage plasticity, and intra-tumor heterogeneity as the next frontiers for realizing individualized patient care. Along with urine as the optimal non-invasive liquid biopsy, BC is at the forefront of the biomarker field. If the goal is to reduce the number of cystoscopies but not to replace them for monitoring recurrence and asymptomatic microscopic hematuria, a BC marker may reach clinical acceptance. As advances in the molecular oncology of BC continue, the next twenty-five years should significantly advance personalized care for BC patients.

RAD51AP1 Loss Attenuates Colorectal Cancer Stem Cell Renewal and Sensitizes to Chemotherapy

DNA damage, induced by either chemical carcinogens or environmental pollutants, plays an important role in the initiation of colorectal cancer. DNA repair processes, however, are involved in both protecting against cancer formation, and also contributing to cancer development, by ensuring genomic integrity and promoting the efficient DNA repair in tumor cells, respectively. Although DNA repair pathways have been well exploited in the treatment of breast and ovarian cancers, the role of DNA repair processes and their therapeutic efficacy in colorectal cancer is yet to be appreciably explored. To understand the role of DNA repair, especially homologous recombination (HR), in chemical carcinogen-induced colorectal cancer growth, we unraveled the role of RAD51AP1 (RAD51-associated protein 1), a protein involved in HR, in genotoxic carcinogen (azoxymethane, AOM)-induced colorectal cancer. Although AOM treatment alone significantly increased RAD51AP1 expression, the combination of AOM and dextran sulfate sodium (DSS) treatment dramatically increased by several folds. RAD51AP1 expression is found in mouse colonic crypt and proliferating cells. RAD51AP1 expression is significantly increased in majority of human colorectal cancer tissues, including BRAF/KRAS mutant colorectal cancer, and associated with reduced treatment response and poor prognosis. Rad51ap1-deficient mice were protected against AOM/DSS-induced colorectal cancer. These observations were recapitulated in a genetically engineered mouse model of colorectal cancer (Apc^{Min /+} ). Furthermore, chemotherapy-resistant colorectal cancer is associated with increased RAD51AP1 expression. This phenomenon is associated with reduced cell proliferation and colorectal cancer stem cell (CRCSC) self-renewal. Overall, our studies provide evidence that RAD51AP1 could be a novel diagnostic marker for colorectal cancer and a potential therapeutic target for colorectal cancer prevention and treatment. IMPLICATIONS: This study provides first in vivo evidence that RAD51AP1 plays a critical role in colorectal cancer growth and drug resistance by regulating CRCSC self-renewal.

HYAL4-V1/Chondroitinase (Chase) Drives Gemcitabine Resistance and Predicts Chemotherapy Failure in Patients with Bladder Cancer

PURPOSE

Gemcitabine-based chemotherapy regimens are first-line for several advanced cancers. Because of better tolerability, gemcitabine + cisplatin is a preferred neoadjuvant, adjuvant, and/or palliative chemotherapy regimen for advanced bladder cancer. Nevertheless, predicting treatment failure and overcoming resistance remain unmet clinical needs. We discovered that splice variant (V1) of HYAL-4 is a first-in-class eukaryotic chondroitinase (Chase), and CD44 is its major substrate. V1 is upregulated in bladder cancer and drives a malignant phenotype. In this study, we investigated whether V1 drives chemotherapy resistance.

EXPERIMENTAL DESIGN

V1 expression was measured in muscle-invasive bladder cancer (MIBC) specimens by qRT-PCR and IHC. HYAL-4 wild-type (Wt) and V1 were stably expressed or silenced in normal urothelial and three bladder cancer cell lines. Transfectants were analyzed for chemoresistance and associated mechanism in preclinical models.

RESULTS

V1 levels in MIBC specimens of patients who developed metastasis, predicted response to gemcitabine + cisplatin adjuvant/salvage treatment and disease-specific mortality. V1-expressing bladder cells were resistant to gemcitabine but not to cisplatin. V1 expression neither affected gemcitabine influx nor the drug-efflux transporters. Instead, V1 increased gemcitabine metabolism and subsequent efflux of difluorodeoxyuridine, by upregulating cytidine deaminase (CDA) expression through increased CD44-JAK2/STAT3 signaling. CDA inhibitor tetrahydrouridine resensitized V1-expressing cells to gemcitabine. While gemcitabine (25-50 mg/kg) inhibited bladder cancer xenograft growth, V1-expressing tumors were resistant. Low-dose combination of gemcitabine and tetrahydrouridine abrogated the growth of V1 tumors with minimal toxicity.

CONCLUSIONS

V1/Chase drives gemcitabine resistance and potentially predicts gemcitabine + cisplatin failure. CDA inhibition resensitizes V1-expressing tumors to gemcitabine. Because several chemotherapy regimens include gemcitabine, our study could have broad significance.

Promotion of epithelial hyperplasia by interleukin-8-CXCR axis in human prostate

BACKGROUND

The clinical manifestation of benign prostatic hyperplasia (BPH) is causally linked to the inflammatory microenvironment and proliferation of epithelial and stromal cells in the prostate transitional zone. The CXC-chemokine interleukin-8 (IL-8) contributes to inflammation. We evaluated the expression of inflammatory cytokines in clinical specimens, primary cultures, and prostatic lineage cell lines. We investigated whether IL-8 via its receptor system (IL-8 axis) promotes BPH.

METHODS

The messenger RNA and protein expression of chemokines, including components of the IL-8 axis, were measured in normal prostate (NP; n = 7) and BPH (n = 21), urine (n = 24) specimens, primary cultures, prostatic lineage epithelial cell lines (NHPrE1, BHPrE1, BPH-1), and normal prostate cells (RWPE-1). The functional role of the IL-8 axis in prostate epithelial cell growth was evaluated by CRISPR/Cas9 gene editing. The effect of a combination with two natural compounds, oleanolic acid (OA) and ursolic acid (UA), was evaluated on the expression of the IL-8 axis and epithelial cell growth.

RESULTS

Among the 19 inflammatory chemokines and chemokine receptors we analyzed, levels of IL-8 and its receptors (CXCR1, CXCR2), as well as, of CXCR7, a receptor for CXCL12, were 5- to 25-fold elevated in BPH tissues when compared to NP tissues (P ≤ .001). Urinary IL-8 levels were threefold to sixfold elevated in BPH patients, but not in asymptomatic males and females with lower urinary tract symptoms (P ≤ .004). The expression of the IL-8 axis components was confined to the prostate luminal epithelial cells in both normal and BPH tissues. However, these components were elevated in BPH-1 and primary explant cultures as compared to RWPE-1, NHPrE1, and BHPrE1 cells. Knockout of CXCR7 reduced IL-8, and CXCR1 expression by 4- to 10-fold and caused greater than or equal to 50% growth inhibition in BPH-1 cells. Low-dose OA + UA combination synergistically inhibited the growth of BPH-1 and BPH primary cultures. In the combination, the drug reduction indices for UA and OA were 16.4 and 7852, respectively, demonstrating that the combination was effective in inhibiting BPH-1 growth at significantly reduced doses of UA or OA alone.

CONCLUSION

The IL-8 axis is a promotor of BPH pathogenesis. Low-dose OA + UA combination inhibits BPH cell growth by inducing autophagy and reducing IL-8 axis expression in BPH-epithelial cells.

RAD51AP1 Deficiency Reduces Tumor Growth by Targeting Stem Cell Self-Renewal

RAD51-associated protein 1 (RAD51AP1) plays an integral role in homologous recombination by activating RAD51 recombinase. Homologous recombination is essential for preserving genome integrity and RAD51AP1 is critical for D-loop formation, a key step in homologous recombination. Although RAD51AP1 is involved in maintaining genomic stability, recent studies have shown that RAD51AP1 expression is significantly upregulated in human cancers. However, the functional role of RAD51AP1 in tumor growth and the underlying molecular mechanism(s) by which RAD51AP1 regulates tumorigenesis have not been fully understood. Here, we use Rad51ap1-knockout mice in genetically engineered mouse models of breast cancer to unravel the role of RAD51AP1 in tumor growth and metastasis. RAD51AP1 gene transcript was increased in both luminal estrogen receptor-positive breast cancer and basal triple-negative breast cancer, which is associated with poor prognosis. Conversely, knockdown of RAD51AP1 (RADP51AP1 KD) in breast cancer cell lines reduced tumor growth. Rad51ap1-deficient mice were protected from oncogene-driven spontaneous mouse mammary tumor growth and associated lung metastasis. In vivo, limiting dilution studies provided evidence that Rad51ap1 plays a critical role in breast cancer stem cell (BCSC) self-renewal. RAD51AP1 KD improved chemotherapy and radiotherapy response by inhibiting BCSC self-renewal and associated pluripotency. Overall, our study provides genetic and biochemical evidences that RAD51AP1 is critical for tumor growth and metastasis by increasing BCSC self-renewal and may serve as a novel target for chemotherapy- and radiotherapy-resistant breast cancer. SIGNIFICANCE: This study provides in vivo evidence that RAD51AP1 plays a critical role in breast cancer growth and metastasis by regulating breast cancer stem cell self-renewal.

A Novel Splice Variant of HYAL-4 Drives Malignant Transformation and Predicts Outcome in Patients with Bladder Cancer

PURPOSE

Poor prognosis of patients with muscle-invasive bladder cancer that often metastasizes drives the need for discovery of molecular determinants of bladder cancer progression. Chondroitin sulfate proteoglycans, including CD44, regulate cancer progression; however, the identity of a chondroitinase (Chase) that cleaves chondroitin sulfate from proteoglycans is unknown. HYAL-4 is an understudied gene suspected to encode a Chase, with no known biological function. We evaluated HYAL-4 expression and its role in bladder cancer.

EXPERIMENTAL DESIGN

In clinical specimens, HYAL-4 wild-type (Wt) and V1 expression was evaluated by RT-qPCR, IHC, and/or immunoblotting; a novel assay measured Chase activity. Wt and V1 were stably expressed or silenced in normal urothelial and three bladder cancer cell lines. Transfectants were analyzed for stem cell phenotype, invasive signature and tumorigenesis, and metastasis in four xenograft models, including orthotopic bladder.

RESULTS

HYAL-4 expression, specifically a novel splice variant (V1), was elevated in bladder tumors; Wt expression was barely detectable. V1 encoded a truncated 349 amino acid protein that was secreted. In bladder cancer tissues, V1 levels associated with metastasis and cancer-specific survival with high efficacy and encoded Chase activity. V1 cleaved chondroitin-6-sulfate from CD44, increasing CD44 secretion. V1 induced stem cell phenotype, motility/invasion, and an invasive signature. CD44 knockdown abrogated these phenotypes. V1-expressing urothelial cells developed angiogenic, muscle-invasive tumors. V1-expressing bladder cancer cells formed tumors at low density and formed metastatic bladder tumors when implanted orthotopically.

CONCLUSIONS

Our study discovered the first naturally-occurring eukaryotic/human Chase and connected it to disease pathology, specifically cancer. V1-Chase is a driver of malignant bladder cancer and potential predictor of outcome in patients with bladder cancer.

Molecular targeting of renal cell carcinoma by an oral combination

The 5-year survival rate of patients with metastatic renal cell carcinoma (mRCC) is <12% due to treatment failure. Therapeutic strategies that overcome resistance to modestly effective drugs for mRCC, such as sorafenib (SF), could improve outcome in mRCC patients. SF is terminally biotransformed by UDP-glucuronosyltransferase-1A9 (A9) mediated glucuronidation, which inactivates SF. In a clinical-cohort and the TCGA-dataset, A9 transcript and/or protein levels were highly elevated in RCC specimens and predicted metastasis and overall-survival. This suggested that elevated A9 levels even in primary tumors of patients who eventually develop mRCC could be a mechanism for SF failure. 4-methylumbelliferone (MU), a choleretic and antispasmodic drug, downregulated A9 and inhibited SF-glucuronidation in RCC cells. Low-dose SF and MU combinations inhibited growth, motility, invasion and downregulated an invasive signature in RCC cells, patient-derived tumor explants and/or endothelial-RCC cell co-cultures; however, both agents individually were ineffective. A9 overexpression made RCC cells resistant to the combination, while its downregulation sensitized them to SF treatment alone. The combination inhibited kidney tumor growth, angiogenesis and distant metastasis, with no detectable toxicity; A9-overexpressing tumors were resistant to treatment. With effective primary tumor control and abrogation of metastasis in preclinical models, the low-dose SF and MU combinations could be an effective treatment option for mRCC patients. Broadly, our study highlights how targeting specific mechanisms that cause the failure of “old” modestly effective FDA-approved drugs could improve treatment response with minimal alteration in toxicity profile.

A chemokine/chemokine receptor signature potentially predicts clinical outcome in colorectal cancer patients

BACKGROUND

Differential expression of chemokines/chemokine receptors in colorectal cancer (CRC) may enable molecular characterization of patients' tumors for predicting clinical outcome.

OBJECTIVE

To evaluate the prognostic ability of these molecules in a CRC cohort and the CRC TCGA-dataset.

METHODS

Chemokine (CXCL-12α, CXCL-12β, IL-17A, CXCL-8, GM-CSF) and chemokine receptor (CXCR-4, CXCR-7) transcripts were analyzed by RT-qPCR in 76 CRC specimens (normal: 27, tumor: 49; clinical cohort). RNA-Seq data was analyzed from the TCGA-dataset (n= 375). Transcript levels were correlated with outcome; analyses: univariate, multivariable, Kaplan-Meier.

RESULTS

In the clinical cohort, chemokine/chemokine receptor levels were elevated 3-10-fold in CRC specimens (P⩽ 0.004) and were higher in patients who developed metastasis (P= 0.03 - < 0.0001). CXCR-4, CXCR-7, CXCL-12α, CXCL-8, IL-17 and GM-CSF levels predicted metastasis (P⩽ 0.0421) and/or overall survival (OS; P⩽ 0.0373). The CXCR-4+CXCR-7+CXCL-12 marker (CXCR-4/7+CXCL-12 (α/b) signature) stratified patients into risk for metastasis (P= 0.0014; OR, 2.72) and OS (P= 0.0442; OR, 2.7); sensitivity: 86.67%, specificity: 97.06%. In the TCGA-dataset, the CXCR-4/7+CXCL-12 signature predicted metastasis (P= 0.011; OR, 2.72) and OS (P= 0.0006; OR: 4.04). In both datasets, the signature was an independent predictor of clinical outcome.

CONCLUSIONS

Results of 451 specimens from both cohorts reveal that the CXCR-4/7+CXCL-12 signature potentially predicts outcome in CRC patients and may allow earlier intervention.

The Effect of Bupivacaine on the Efficacy of Antibiotic Coating on Penile Implants in Preventing Infection

Background

In an effort to reduce dependence on opioids following inflatable penile prosthesis placement, intra-operative soaking of the implant in Bupivacaine (BUP) has been proposed as part of a multimodal approach to pain control. However, no study has shown if the addition of BUP affects the antimicrobial properties of InhibiZone on AMS700 (Boston Scientific, Marlborough, MA) and/or of antibiotic soaked Titan Coloplast (Coloplast Corporation, Minneapolis, MN).

Aim

To determine if BUP alters the zone of inhibition (ZOI) against Staphylococcus epidermidis (S epidermidis) and Escherichia coli (E coli), common gram-positive and gram-negative bacterial causes of infection, respectively, created by InhibiZone coated AMS and/or by antibiotic-soaked Coloplast implant.

Methods

S epidermidis and E coli were spread on agar plates. After a 30-minute incubation, four AMS with InhibiZone strips treated with sterile saline or BUP (1.25 mg/mL) were placed on a plate. 4 Coloplast strips were dipped in varying routinely used concentrations of Rifampin (0–10 mg/mL) plus Gentamicin (0–1 mg/mL; rifampin and gentamicin (R+G)) solution with or without BUP. The ZOI for AMS with InhibiZone and Coloplast dipped in antibiotic solution was measured using ImageJ software. Normalized ZOI was calculated as (ZOI area/plate area) × 100. Unpaired t-test compared the mean ± SD ZOI between BUP and no BUP groups (n = 4/group).

Outcomes

The primary outcome of the study was the ZOI against E coli and S epidermidis at 24 and 48 hours.

Results

Growth of both S epidermidis and E coli at 24 and 48 hours of incubation was inhibited in both implants and the addition of BUP did not alter the ZOI. Coloplast strips dipped in R+G produced a ZOI in a dose-dependent manner. Interestingly, the ZOI against S epidermidis compared to that of E coli was much wider for both implants.

Clinical Implications

This suggests that the use of BUP does not affect the protective effects of antibiotic dips and can potentially be used during penile prosthesis surgery pending clinical trials.

Strengths and Limitations

This is the first study to evaluate the effect of BUP on anti-bacterial dips. As with all in vitro analysis, further research must be done to see if these findings hold true in the clinical setting.

Conclusions

The addition of BUP does not impede the in vitro antibacterial activity of InhibiZone-coated AMS or R+G-soaked Coloplast. Whether these in vitro findings translate to surgical outcomes needs to be evaluated in future preclinical trials.

Lokeshwar SD, Horodyski L, Lahorewala SS, et al. The Effect of Bupivacaine on the Efficacy of Antibiotic Coating on Penile Implants in Preventing Infection. J Sex Med 2019;7:337−344.

Abstract 1259: HYAL4: The first study on a potential molecular driver and biomarker of invasive bladder cancer

INTRODUCTION AND OBJECTIVE: The majority of morbidity and mortality in bladder cancer (BCa) patients is due to muscle invasive bladder cancer (MIBC). The prognosis of patients with MIBC could be improved by identification of novel biomarkers and therapeutic agents. Chondroitin sulfate proteoglycans are known to promote tumor growth and metastasis. However, a Chondroitinase (Chase) that degrades chondroitin sulfate has not been identified. HYAL4, a member of the glycosaminoglycan (GAG) degrading enzyme-family, potentially has Chase activity; however, HYAL4 (HY4) has not be studied in any biological system, normal or disease. In this study, we evaluated the expression of all six members of the GAG-degrading enzyme family in BCa specimens and evaluated HY4 functions in preclinical models of BCa.

METHODS: Cohort 1: 79 bladder tissues (normal (NBL) = 31; tumor (TBL) = 52); cohort 2: 40 cystectomy specimens from MIBC patients who received adjuvant Gemcitabine plus cisplatin (G+C) treatment for metastatic disease with chemotherapy. Gene expression was measured by q-PCR in both cohorts. HY4 was either overexpressed (HY4) or knocked-down in immortalized normal urothelial (Urotsa) and 3 BCa cell lines. Transfectants were assayed for Chase activity, anchorage independent growth, motility, invasion, molecular signaling. Tumor growth and metastasis in intravesical examined in HT1376 bladder orthotopic model.

RESULTS: In cohort 1 HYAL1, HYAL4 mRNA levels were significantly (6-13-fold) elevated in TBL tissues when compared to NBL tissues (P&lt;0.001). HY4 levels were 7-fold elevated in MIBC. HY4 levels were an independent predictor of metastasis and death due to BCa (chi-sq: 6.9; P=0.0087; chi-sq: 7.59; P=0.006). In cohort 2, high HY4 levels significantly correlated with G+C treatment failure (chi-sq: 8.7; P=0.003) with &gt; 80% accuracy. HY4-expressing transfectants secreted HY4 and Chase activity in their conditioned media. Overexpression of HY4 in normal urothelial and BCa cells significantly increased, while its knockdown abrogated, anchorage-independent growth, invasion, chemotactic motility (&gt; 3-fold). HY4 expression induced Gemcitabine resistance (IC50: vector: 3.1 nM; HY4: 126 nM). HY4 expression upregulated a stem cell signature. Urothelial cells expressing HY4 formed tumors in NOD/SCID mice. HY4-expressing BCa cells metastasized to lung and spleen in an orthotopic BCa model.

Citation Format: Daley S. Morera, Sarrah S. Lahorewala, Soum D. Lokeshwar, Andre R. Jordan, Vinata B. Lokeshwar. HYAL4: The first study on a potential molecular driver and biomarker of invasive bladder cancer [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 1259.

Abstract 2080: Novel molecularly targeted combination for renal cell carcinoma

INTRODUCTION: Despite many available treatments, &gt;90% of metastatic renal cell carcinoma (mRCC) patients die within 5 years. Due to its modest efficacy, Sorafenib (SF) is a second line treatment for mRCC. Molecular basis for SF failure is unknown. Hymecromone (HC) is a non−toxic orally bioavailable agent used in Europe for improving liver health. We examined the molecular basis of SF failure in clinical specimens and provided mechanistic evidence for why SF+HC could be a potent therapeutic combination against mRCC.

METHODS: UGT1A9 (A9) levels and SF glucuronidation were measured in kidney specimens (45 normal; 86 tumor) by qPCR and a glucuronidation assay using tumor microsomes. Response to SF+HC combination in vector-only (EV), A9-overexpressing (A9) and A9-knockdown (A9-KO) 786-0 and Caki-1 transfectants, primary RCC spheroids, and endothelial cells was examined by proliferation, apoptosis, motility and invasion assays. Target analysis was performed by immunoblot. Treatment efficacy was evaluated in Caki−1 s.c. and orthotopic xenograft models, with bioluminescence imaging.

RESULTS: A9 has been shown to glucuronidate and inactivate SF. A9 levels were 8-10-fold elevated in mRCC patients’ tumors compared to non-mRCC patients and normal kidney tissues. A9 levels were an independent predictor of metastasis (P=0.022; efficacy: 73%; sensitivity: 93.8%). Tumor microsomes from mRCC patients’ glucuronidated SF 5-fold higher than from non-mRCC patients. In RCC cells, HC treatment downregulated A9 levels, A9 promoter activity and inhibited SF-glucuronidation. SF (5 µM) and HC (20-40 µg/ml) combination inhibited RCC cell and primary tumor spheroid proliferation (&gt;90%), motility/invasion (&gt;80%), and induced apoptosis (5-fold). While A9 transfectants were resistant to SF+HC treatment, A9-KO cells were sensitive to SF alone. Endothelial cells co-cultured with A9 transfectants were resistant to SF+HC treatment. SF+HC upregulated apoptosis effectors, but downregulated CD44, RHAMM, and phospho-Met levels in EV but not A9 transfectants. HC (100 or 200 mg/kg) and SF (30 mg/kg) oral combination abrogated Caki−1 tumor growth (&gt;80%) without serum/tissue toxicity. HC+SF treatment decreased A9 levels, Ki67 index and microvessel density. A9-overexpressing tumors were resistant to treatment.

CONCLUSION: This is the first study to demonstrate that A9 overexpression in mRCC is likely a mechanism of SF failure and A9 downregulation can re-sensitize cells. HC+SF is an orally bioavailable and non-toxic combination that may be an effective therapeutic strategy for mRCC.

Citation Format: Andre R. Jordan, Jiaojiao Wang, Luis E. Lopez, Daley S. Morera, Vinata B. Lokeshwar. Novel molecularly targeted combination for renal cell carcinoma [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 2080.

Abstract 462: Results from multiple datasets including the TCGA reveal limited clinical significance of molecular subtypes in bladder cancer

INTRODUCTION AND OBJECTIVE: Molecular subtypes have been suggested to predict outcome in patients with muscle invasive bladder cancer (MIBC). The major subtypes reported have been “luminal” and “basal”; however, there is little consensus regarding subtype-signatures and the clinical parameters used to evaluate outcome. The objective of this study was to examine using multiple datasets, if molecular subtypes are distinct entities within MIBC and whether they predict clinical outcome.

METHODS: We analyzed transcriptome data from all 402 MIBC samples in The Cancer Genome Atlas (TCGA) and 151 high-grade MIBC samples from three datasets in Oncomine™. Transcript levels were also measured in 52 bladder tumor specimens with clinical follow-up (cohort-1). Samples were subtype-scored using gene panels (GP-11, GP-30, BASQ) consisting only of those genes common among published studies. Correlation of subtypes to recurrence/progression-free survival (R/PFS), metastasis, cancer-specific survival (CSS) and overall-survival (OS) was examined by logistic regression, Cox proportional Hazards model and Kaplan-Meier analyses.

RESULTS: Based on GP-11 subtype-scoring, &gt;75% of the MIBC TCGA-dataset samples were mixed, i.e. neither pure-luminal nor pure-basal. When tumors were categorized as pure-luminal, pure-basal, or mixed, the subtypes could not predict OS or R/PFS. Consistent with published studies, when tumors were categorized as luminal or basal the subtypes predicted OS (P=0.051); sensitivity: 53.9%; specificity: 62%. Subtypes also correlated with tumor-grade (P=0.0005); most low-grade MIBC cases (16/21) in the TCGA-dataset were luminal. However, MIBC is rarely low-grade and subtypes could not predict OS (P=0.131) when only high-grade cases were included. Subtypes were not significant prognosticators in multivariate analyses. GP-30 and BASQ panels validated these results. In the Oncomine-dataset and cohort-1, subtypes could not predict metastasis, CSS, or OS.

CONCULUSIONS: Our study of multiple datasets reveals that molecular subtypes may reflect tumor-heterogeneity but are likely not distinct entities within MIBC. Furthermore, molecular subtypes have limited prognostic capability for MIBC patients. Although there is a need to individualize patient care, further examination into the molecular subtypes of MIBC is needed before their incorporation into clinical practice.

Citation Format: Sarrah S. Lahorewala, Daley S. Morera, Jiaojiao Wang, Vinata B. Lokeshwar. Results from multiple datasets including the TCGA reveal limited clinical significance of molecular subtypes in bladder cancer [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 462.

β-Arrestins Regulate Stem Cell-Like Phenotype and Response to Chemotherapy in Bladder Cancer

β-Arrestins are classic attenuators of G-protein-coupled receptor signaling. However, they have multiple roles in cellular physiology, including carcinogenesis. This work shows for the first time that β-arrestins have prognostic significance for predicting metastasis and response to chemotherapy in bladder cancer. β-Arrestin-1 (ARRB1) and β-arrestin-2 (ARRB2) mRNA levels were measured by quantitative RT-PCR in two clinical specimen cohorts (n = 63 and 43). The role of ARRBs in regulating a stem cell-like phenotype and response to chemotherapy treatments was investigated. The consequence of forced expression of ARRBs on tumor growth and response to Gemcitabine in vivo were investigated using bladder tumor xenografts in nude mice. ARRB1 levels were significantly elevated and ARRB2 levels downregulated in cancer tissues compared with normal tissues. In multivariate analysis only ARRB2 was an independent predictor of metastasis, disease-specific-mortality, and failure to Gemcitabine + Cisplatin (G+C) chemotherapy; ∼80% sensitivity and specificity to predict clinical outcome. ARRBs were found to regulate stem cell characteristics in bladder cancer cells. Depletion of ARRB2 resulted in increased cancer stem cell markers but ARRB2 overexpression reduced expression of stem cell markers (CD44, ALDH2, and BMI-1), and increased sensitivity toward Gemcitabine. Overexpression of ARRB2 resulted in reduced tumor growth and increased response to Gemcitabine in tumor xenografts. CRISPR-Cas9-mediated gene-knockout of ARRB1 resulted in the reversal of this aggressive phenotype. ARRBs regulate cancer stem cell-like properties in bladder cancer and are potential prognostic indicators for tumor progression and chemotherapy response.

Abstract 2655: HYAL4: A molecular driver and potential marker of invasive bladder cancer

INTRODUCTION AND OBJECTIVES: Muscle invasive bladder cancer (MIBCa) causes the majority of morbidity and mortality in BCa patients. Prognosis of MIBCa patients may be improved by ide ntification of novel prognostic biomarkers and therapeutic targets. Chondroitin sulfate proteoglycans are known to promote tumor growth and metastasis. However, a Chondroitinase (Chase) that degrades chondroitin sulfate has not been identified. HYAL4, a member of the glycosaminoglycan (GAG) degrading enzyme-family, potentially has Chase activity; however, HYAL4 (HY4) has not be studied in any biological system, normal or disease. The objective of this study was to evaluate the expression of all six members of the GAG-degrading enzyme family in bladder cancer (BCa) specimens and to investigate HY4 functions in preclinical models of BCa.

METHODS: Q-PCR was performed to measure mRNA levels of GAG-degrading enzyme family genes in 59 bladder tissues (normal (NBL) = 25; tumor (TBL) = 38). HY4 expression was also measured in 40 cystectomy specimens from MIBCa patients who later were treated for metastatic disease with Gemcitabine plus cisplatin (G+C) chemotherapy. HY4 was either stably expressed or knocked-down in immortalized urothelial and BCa cell lines. Transfectants were assayed for Chase activity, anchorage independent growth, motility, invasion, molecular signaling. Tumor growth and metastasis was monitored by bioluminescence imaging.

RESULTS: Among the 6 genes, HYAL1 and HY4 mRNA levels were significantly (6-13-fold) elevated in TBL tissues when compared to NBL tissues (P&lt;0.001). HY4 levels were 7-fold elevated in muscle invasive BCa. In univariate and multivariate analyses, HY4 predicted metastasis and death due to BCa (chi-sq: 6.93; P=0.0089; risk-ratio: 6.9). In metastatic BCa patients, high HY4 levels significantly correlated with G+C treatment failure (χ2 = 7.5; P=0.0062) with &gt; 80% accuracy. HY4-expressing transfectants secreted HY4 and Chase activity in their conditioned media. Overexpression of HYAL-4 in normal urothelial and BCa cells significantly increased, while its knockdown abrogated, anchorage-independent growth, invasion, and chemotactic motility (&gt; 3-fold). HY4 expression induced Gemcitabine resistance (IC50: vector: 3.1 nM; HY4: 126 nM). HY4 expression upregulated a stem cell signature. Urothelial cells expressing HY4 formed tumors in NOD/SCID mice. HY4-expressing BCa cells metastasized to lung and spleen in an orthotopic BCa model.

CONCLUSION: This first study on HY4 shows that it is a novel molecular determinant of MIBCa and Gemcitabine resistance and a potential marker for clinical outcome.

Citation Format: Sarrah S. Lahorewala, Daley S. Morera, Andre R. Jordan, Vinata B. Lokeshwar. HYAL4: A molecular driver and potential marker of invasive bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2655.

Abstract 4614: Molecular subtypes in muscle invasive bladder cancer: Evaluation of clinical significance

Introduction: Using RNA-seq (HiSeq) transcriptome data in The Cancer Genome Atlas (TCGA) bladder cancer (BCa) dataset two molecular subtypes, basal and luminal, were identified in muscle invasive BCa (MIBCa). Recurring reported markers of the basal subtype are KRT5, KRT6A, KRT14 high and KRT20, GATA3, UPK3A, FOXA1 low. The luminal subtype is the opposite pattern of expression. Double-Negative (DN) subtype was defined as no expression of the 7 markers. Luminal, basal and DN subtypes were reported as predictors of better, poor and worst prognosis, respectively, based on overall survival (OS). EGFR is defined as a squamous differentiation marker associated with poor prognosis. The objective was to assess the clinical significance of these subtypes in TCGA data with validation in datasets from Oncomine.

Methods: TCGA dataset containing 407 MIBCa patients was accessed through Xena Browser. The dataset included patient demographics, clinical parameters, OS, recurrence-free survival (RFS) and the transcript levels (log2(nor._count+1) of basal and luminal markers. All available follow-up data was included (27.9±28.49; max: 166 months). 25 BCa datasets (n=360 MIBCa patients) containing these same variables were accessed through Oncomine. High and low levels were stratified by median. Association of individual basal and luminal markers and the subtypes with clinical and outcome variables was analyzed by univariate and multivariate analyses. Kaplan-Meier analysis was performed to stratify patients into risk groups for OS and RFS.

Results: In TCGA data, neither basal nor luminal markers levels significantly correlated with metastasis or lymphovascular invasion (LVI); P = 0.2 to 0.9. Only KRT5 significantly but inversely correlated with lymph node (LN) positivity; P=0.011. EGFR levels did not correlate with metastasis, LVI, or LN positivity; P &gt; 0.05. In TCGA dataset 77 (18.9%), 50 (12.3%) and 14 (3.4%) expressed basal, luminal and DN subtypes, respectively; 266 (66.4%) patients did not conform to any group. In univariate or multivariate analyses, the subtypes also did not correlate with metastasis, LVI or LN status. Only luminal subtype associated with better OS; P=0.003. However no subtype significantly correlated with RFS. In KM analysis no subtype stratified patients regarding RFS (P&gt;0.2). Oncomine BCa datasets validated these results.

Conclusion: TCGA and Oncomine datasets show that the majority of MIBCa tissues express a mixed pattern of basal and luminal markers. Furthermore, basal, luminal or DN subtypes do not associate with clinical parameters or prognosis of MIBCa patients.

Citation Format: Daley S. Morera, Daniel Belew, Andre R. Jordan, Vinata B. Lokeshwar. Molecular subtypes in muscle invasive bladder cancer: Evaluation of clinical significance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4614.

Abstract 1146: Biomarker-driven targeted oral treatment strategy for bladder cancer

INTRODUCTION AND OBJECTIVE: Hyaluronic acid (HA) family of molecules, HA-synthases (HAS-1,2,3), HA-receptors (CD44, RHAMM) and hyaluronidase (HYAL-1) are markers for bladder cancer (BCa) diagnosis and predicting prognosis. HA-family promotes tumor growth and metastasis by inducing epithelial mesenchymal transition (EMT). 4-Methylumbelliferone (4-MU) is an orally bioavailable dietary supplement that inhibits HA synthesis. We evaluated the expression of HA family and EMT markers in bladder tissues as well as the antitumor effects of 4-MU as a potential targeted therapeutic agent in preclinical models of BCa.

METHODS: Quantitative PCR was used to measure mRNA expression of HA-family and EMT genes (β-catenin, Twist, and Snail) in 72 bladder tissue specimens (28 normal; 44 tumor); follow-up: 20.3±2.5 months; median 17 months. The effect of 4-MU (0-0.6 mM) on cell proliferation, apoptosis, intracellular signaling, and the expression of HA receptors, and EMT genes were examined in BCa cell lines by Q-PCR, immunoblotting, proximal ligation and PI-3K activity assays. Mechanism of action was analyzed by HA addition and mAkt overexpression. Effect of oral administration of 4-MU (100, 200-mg/kg) on tumor growth was analyzed in subcutaneous xenografts.

RESULTS: HAS-1, -2 -3, HYAL-1 and Snail levels were 10-20-fold elevated in BCa tissues as compared to normal bladder (P&lt;0.001). In univariate analysis, HAS-1, -2, HYAL-1 and Twist levels correlated with metastasis (P&lt;0.001); HYAL-1 was an independent predictor of metastasis. 4-MU inhibited cell proliferation, chemotactic motility and invasion in a dose-dependent manner; 50-70% inhibition at IC50 (0.4 mM) for HA-synthesis inhibition. 4-MU induced apoptosis (&gt;3-fold) via the death receptor pathway. 4-MU downregulated HA-signaling, specifically transcript and/or protein levels of CD44, RHAMM, p-Akt, β-catenin, pβ-catenin(S552). Snail and twist were downregulated by 2-5-fold, but pβcatenin((T41/S45), pGSK-3α/β and E-cadherin levels were increased. 4-MU also inhibited CD44/PI-3K complex formation and PI-3K activity. HA addition or myristoylated Akt expression attenuated 4-MU effects. In xenograft studies, 4-MU oral treatment abrogated tumor growth of established tumors (vehicle, day 50: 766±221 mm3; 4-MU: 128±61, day 50) by abrogating HA-synthesis. No weight loss or serum or organ toxicity was observed in treated mice.

CONCULUSION: This study demonstrates that HA-family signaling is upregulated in BCa and can be specifically targeted for treatment by a non-toxic dietary supplement. Support: 7R01 CA072821-16; 7R01CA176691-03

Citation Format: Daley S. Morera, Andre Jordan, Vinata B. Lokeshwar. Biomarker-driven targeted oral treatment strategy for bladder cancer [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 1146. doi:10.1158/1538-7445.AM2017-1146

Abstract 1549: Prognostic significance and tumor suppressive functions of SDCT2 in renal cell carcinoma

Introduction: Five-year survival of metastatic renal cell carcinoma (mRCC) patients is &lt; 10% and African American (AA) males have the highest incidence. Identification of the molecular determinants of mRCC and racial disparity in RCC is critical for biomarker development and targeted therapy. SDCT2 is expressed in kidney epithelial cells and is a succinate and citrate transporter, but its role has not been examined in any benign diseases or cancer. We examined SDCT2 expression in normal and RCC tissues and correlated it with clinical outcome and racial disparity. We also evaluated the biological functions and molecular signaling regulated by SDCT2 in RCC cells.

Methods: Differential gene expression in the matched normal and RCC tissues (n=6/category) was evaluated by microarray analysis; results were validated by quantitative-PCR and immunoblotting in normal and RCC tissues from 53 patients (White=21; Hispanic=19; AA=13). VHL+ and VHL- RCC cells were stably transfected with a Flag-tagged SDCT2 construct. Transfectants were characterized for cell proliferation, cell cycle, motility, succinate/citrate transport and reactive oxygen species (ROS) measurement assays under normoxia and hypoxia (1% O2); cell death and senescence pathway markers were also evaluated. SDCT2 induction was evaluated following 5-azacytidine plus Trichostatin A treatment

Results: SDCT2 was 63- and 100-fold downregulated in low- and high-stage RCC tissues, respectively. Q-PCR validation showed that SDCT2 levels were 40-fold downregulated in tumor tissues when compared to normal kidney (P&lt;0.0001 Mann-Whitney test). Downregulation was 40-fold in White and Hispanic patients, but 198-fold in AA patients (P=0.0049) and also correlated with tumor stage and metastasis (P=0.009). Under hypoxia, SDCT2 expression caused over 3-fold inhibition of proliferation, cell-cycle (G1-S block), and motility in both VHL+ and VHL- cells (P&lt;0.01), only VHL+ cells were inhibited under normoxia. SDCT2 expression induced ROS levels and succinate transport by 3-fold in RCC cells (P&lt;0.01). SDCT2 expression induced the p16INK4a-RB pathway and apoptosis (caspase-3 and PARP activation). 5-AZA+TSA treatment caused a 50-fold induction (P&lt;0.0001) of SDCT2 expression.

Conclusion: This is the first study on a functional biomarker in RCC, SDCT2, that is a possible novel tumor suppressor gene. SDCT2 loss promotes RCC growth, survival and inhibits cellular senescence and its downregulation correlates with metastasis and racial disparity. Support: Grant NCI/NIH 5R01CA72821; 5R01CA176691

Citation Format: Andre R. Jordan, Martin Hennig, Daley S. Morera, Soum D. Lokeshwar, Asif Talukder, Lokeshwar Vinata. Prognostic significance and tumor suppressive functions of SDCT2 in 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 1549. doi:10.1158/1538-7445.AM2017-1549