Citations

Abstract Background: The four most commonly-mutated genes in clear cell renal cell carcinoma (ccRCC) tumors are BAP1, PBRM1, SETD2 and VHL. And, there are currently 14 known RCC germline variants that have been reproducibly shown to be associated with RCC risk. However, the association of germline genetics with tumor genetics and clinical aggressiveness are unknown.Methods: We analyzed 420 ccRCC patients from The Cancer Genome Atlas (TCGA). Molecular subtype was determined based on acquired mutations in BAP1, PBRM1, SETD2 and VHL. Aggressive subtype was defined clinically using Mayo SSIGN score and molecularly using the ccA/ccB gene expression subtype. Publically-available Hi-C data were used to link germline risk variants with candidate target genes. Results: The 8q24 variant rs35252396 was significantly associated with VHL mutation status (OR=1.6, p=0.0037) and SSIGN score (OR=1.9, p=0.00094), after adjusting for multiple comparisons. We observed that, while some germline variants have interactions with nearby genes, some variants demonstrate long-range interactions with target genes.Conclusions: These data further demonstrate the link between rs35252396, HIF pathway and ccRCC clinical aggressiveness, providing a more comprehensive picture of how germline genetics and tumor genetics interact with respect to tumor development and progression.

Abstract Background The four most commonly-mutated genes in clear cell renal cell carcinoma (ccRCC) tumors are BAP1 , PBRM1 , SETD2 and VHL . And, there are currently 14 known RCC germline variants that have been reproducibly shown to be associated with RCC risk. However, the association of germline genetics with tumor genetics and clinical aggressiveness are unknown. Methods We analyzed 420 ccRCC patients from The Cancer Genome Atlas (TCGA). Molecular subtype was determined based on acquired mutations in BAP1 , PBRM1 , SETD2 and VHL . Aggressive subtype was defined clinically using Mayo SSIGN score and molecularly using the ccA/ccB gene expression subtype. Publically-available Hi-C data were used to link germline risk variants with candidate target genes. Results The 8q24 variant rs35252396 was significantly associated with VHL mutation status (OR=1.6, p=0.0037) and SSIGN score (OR=1.9, p=0.00094), after adjusting for multiple comparisons. We observed that, while some germline variants have interactions with nearby genes, some variants demonstrate long-range interactions with target genes. Conclusions These data further demonstrate the link between rs35252396, HIF pathway and ccRCC clinical aggressiveness, providing a more comprehensive picture of how germline genetics and tumor genetics interact with respect to tumor development and progression.

Abstract Purpose: Quiescin Sulfhydryl Oxidase 1 (QSOX1) is an enzyme over-expressed by tumor cells. Our group and others have shown that QSOX1 is involved in invasion and metastasis. We previously reported that a small molecule, SBI-183, inhibited the enzymatic activity of QSOX1 and suppressed tumor cell invasion in vitro and metastasis of MDA-MB-231 breast tumor cells in vivo. In our current work we tested SPX-009, an analog of SBI-183 with increased potency, to suppress invasion and metastasis in vitro and in vivo. Methods: Commercially available analogs for SBI-183 were screened in a cell-free fluorescent screening assay for the ability to inhibit QSOX1. Analog compounds that inhibited QSOX1 in a concentration-dependent manner were then tested for the ability to inhibit growth and invasion of triple negative breast cancer (TNBC) cells (MDA-MB-231), sarcomatoid kidney cancer cells (RCJ-41T2) and pancreatic adenocarcinoma cells (MIAPaCa2). MTT assays were used to measure the effect of the compounds on tumor growth. 2D invasion assays and 3D tumor spheroid assays were employed to measure the effect of the analogs on invasion. One potent analog (SPX-009) was evaluated for the ability to suppress tumor growth and metastasis in mice bearing MDA-MB-231-luc breast cancer orthotopic xenografts. Results: Three of 53 analogs inhibited the enzymatic activity of QSOX1 at levels similar to the parent compound. However, one of those compounds, SPX-009, suppressed invasion of breast, kidney and pancreas tumor cells in 2D and 3D invasion assays at >10-fold lower concentrations than the parent compound (SBI-183). In a non-metastatic xenograft of kidney cancer SBI-183 suppressed primary kidney tumor growth by 51%, but in a metastatic xenograft breast cancer model (MDA-MB-231-luc TNBC), SBI-183 reduced lung metastasis by 76% compared to control. Human-mouse xenograft studies are ongoing with the more potent analog (SPX-009) and will also be presented. Conclusions: Chemical inhibitors of QSOX1 have a minor effect on tumor cell viability, but a major effect on tumor cell invasion in vitro and metastasis in vivo. This finding suggests that combining a QSOX1 inhibitor with a cytotoxic agent might provide a means to inhibit metastasis of cells that are resistant to cytotoxic agents. Citation Format: Amber Fifield, Thai H. Ho, Douglas O. Faigel, Sergei Svarovsky, Eduard Sergienko, Thomas C. Chung, Douglas F. Lake. Chemical inhibitors of quiescin sulfhydryl oxidase (QSOX1) suppress tumor invasion and metastasis [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5323.

Abstract Background: The four most commonly-mutated genes in clear cell renal cell carcinoma (ccRCC) tumors are BAP1, PBRM1, SETD2 and VHL. And, there are currently 14 known RCC germline variants that have been reproducibly shown to be associated with RCC risk. However, the association of germline genetics with tumor genetics and clinical aggressiveness are unknown.Methods: We analyzed 420 ccRCC patients from The Cancer Genome Atlas (TCGA). Molecular subtype was determined based on acquired mutations in BAP1, PBRM1, SETD2 and VHL. Aggressive subtype was defined clinically using Mayo SSIGN score and molecularly using the ccA/ccB gene expression subtype. Publically-available Hi-C data were used to link germline risk variants with candidate target genes. Results: The 8q24 variant rs35252396 was significantly associated with VHL mutation status (OR=1.6, p=0.0037) and SSIGN score (OR=1.9, p=0.00094), after adjusting for multiple comparisons. We observed that, while some germline variants have interactions with nearby genes, some variants demonstrate long-range interactions with target genes.Conclusions: These data further demonstrate the link between rs35252396, HIF pathway and ccRCC clinical aggressiveness, providing a more comprehensive picture of how germline genetics and tumor genetics interact with respect to tumor development and progression.

Abstract Purpose: Clear cell renal cell carcinoma (ccRCC) is frequently associated with inactivation of the von Hippel–Lindau tumor suppressor, resulting in activation of HIF-1α and HIF-2α. The current paradigm, established using mechanistic cell-based studies, supports a tumor promoting role for HIF-2α, and a tumor suppressor role for HIF-1α. However, few studies have comprehensively examined the clinical relevance of this paradigm. Furthermore, the hypoxia-associated factor (HAF), which regulates the HIFs, has not been comprehensively evaluated in ccRCC. Experimental Design: To assess the involvement of HAF/HIFs in ccRCC, we analyzed their relationship to tumor grade/stage/outcome using tissue from 380 patients, and validated these associations using tissue from 72 additional patients and a further 57 patients treated with antiangiogenic therapy for associations with response. Further characterization was performed using single-cell mRNA sequencing (scRNA-seq), RNA-in situ hybridization (RNA-ISH), and IHC. Results: HIF-1α was primarily expressed in tumor-associated macrophages (TAMs), whereas HIF-2α and HAF were expressed primarily in tumor cells. TAM-associated HIF-1α was significantly associated with high tumor grade and increased metastasis and was independently associated with decreased overall survival. Furthermore, elevated TAM HIF-1α was significantly associated with resistance to antiangiogenic therapy. In contrast, high HAF or HIF-2α were associated with low grade, decreased metastasis, and increased overall survival. scRNA-seq, RNA-ISH, and Western blotting confirmed the expression of HIF-1α in M2-polarized CD163-expressing TAMs. Conclusions: These findings highlight a potential role of TAM HIF-1α in ccRCC progression and support the reevaluation of HIF-1α as a therapeutic target and marker of disease progression.

Background Abnormal circadian blood pressure ( BP ) variations during sleep, specifically the non‐dipping (<10% fall in nocturnal BP ) and reverse‐dipping patterns (rise in nocturnal BP ), have been associated with an increased risk of cardiovascular events and target organ damage. However, the relationship between abnormal sleep BP variations and cerebral small vessel disease markers is poorly established. This study aims to assess the association between non‐dipping and reverse‐dipping BP patterns with markers of silent cerebral small vessel disease. Methods and Results MEDLINE , Embase, and Cochrane Databases were searched from inception through November 2019. Studies that reported the odds ratios (ORs) for cerebral small vessel disease markers in patients with non‐dipping or reverse‐dipping BP patterns were included. Effect estimates from the individual studies were extracted and combined using the random‐effect, generic inverse variance method of DerSimonian and Laird. Twelve observational studies composed of 3497 patients were included in this analysis. The reverse‐dipping compared with normal dipping BP pattern was associated with a higher prevalence of white matter hyperintensity with a pooled adjusted OR of 2.00 (95% CI , 1.13–2.37; I 2 =36%). Non‐dipping BP pattern compared with normal dipping BP pattern was associated with higher prevalence of white matter hyperintensity and asymptomatic lacunar infarction, with pooled OR s of 1.38 (95% CI , 0.95–2.02; I 2 =52%) and 2.33 (95% CI , 1.30–4.18; I 2 =73%), respectively. Limiting to only studies with confounder‐adjusted analysis resulted in a pooled OR of 1.38 (95% CI , 0.95–2.02; I 2 =52%) for white matter hyperintensity and 1.44 (95% CI , 0.97–2.13; I 2 =0%) for asymptomatic lacunar infarction. Conclusions The non‐dipping and reverse‐dipping BP patterns are associated with neuroimaging cerebral small vessel disease markers.

e17587 Background: Radium (Ra)-223 has become the cornerstone treatment in patients with metastatic castrate-resistant prostate cancer (mCRPC) with bone metastases. Ra-223 has been shown to suppress abnormal bone formation by inducing DNA double-strand breaks in tumor cells. This can reduce skeletal-related events, as well as improve survival and quality of life. Studies have indicated mutations that regulate DNA damage response in prostate cancer as susceptible to PARP inhibitors and platinum-based therapies. This study aims to evaluate mCRPC response to Ra-223 stratified by tumor genomics. Methods: This is a retrospective study of mCRPC patients who received Ra-223 and genetic testing within the Mayo Clinic database (Arizona, Florida, and Minnesota). Patient demographics, genetic mutations, treatment responses in terms of alkaline phosphatase (ALP) and prostate-specific antigen (PSA), and survival were assessed. Primary end points were progression-free survival (PFS) and overall survival (OS) from time of first radium treatment. Results: 239 mCRPC patients treated with Ra-223 were identified. Germline and/or somatic genetic sequencing was available in 50 patients, who had a median age of 61 years at time of diagnosis and 68 years at time of Ra-223 treatment. Median Gleason score at time of diagnosis was 8.0. 100% of patients received prior androgen deprivation therapy. 72% received prior docetaxel, and 18% received prior cabazitaxel. Notable mutations included TP53 (45.2%), TMPRSS2-ERG (28.6%), PTEN (26.2%), BRCA1/2 (14.3%), ATM (9.3%), CDK12 (7.1%), and Rb (4.9%). TMPRSS2-ERG was the second most commonly found mutation, with median OS 12.7 mo versus 15.4 mo in patients without TMPRSS2-ERG mutations (p = 0.099). In patients with CDK12 mutations (2 of 28 tested positive), PFS was 10.4 mo versus 5.6 mo in patients without CDK12 mutations (p = 0.157). The assessment of ALP and PSA response to radium treatment stratified by genetic mutation did not reach statistical significance. Conclusions: Among mCRPC patients treated with Ra-223 at Mayo Clinic, TMPRSS2-ERG was the second most commonly found genetic mutation and had observed worse survival outcomes that approached statistical significance. Prospective studies and increased sample sizes are needed to determine the impact of genetic mutations in response to Ra-223.

3535 Background: Peripheral blood allows for a simple non-invasive method for isolating various cancer associated circulating stromal cells (CStCs) which may predict for cancer presence. Cancer Associated Macrophage-Like cells (CAMLs), a specific CStC, are phagocytic myeloid cells that derive from an immunological response to cancer and emanate from primary tumors. Using a filtration platform we screened the peripheral blood of untreated newly diagnosed cancer patients (n = 308) for CAMLs. In parallel, we screened patients with newly diagnosed non-malignant diseases, i.e. lupus, benign cysts, etc. (n = 39), and healthy control samples (n = 76). We found that CAMLs are highly prevalent (87%) in the blood of cancer patients, but uncommon in non-malignant conditions (20%) & absent in healthy individuals (0%). Methods: Anonymized peripheral blood were taken from 308 cancer patients after confirmation of invasive malignancy [stage I (n = 76), stage II (n = 73), stage III (n = 72), stage IV (n = 65) and unstaged non-metastatic (n = 22)] with pathologically confirmed lung (n = 65), pancreas (n = 53), breast (n = 52), prostate (n = 40), esophageal (n = 30), renal cell (n = 18), hepatocellular (n = 15), neuroblastoma (n = 10), melanoma (n = 8), and other (n = 17). Further, anonymized blood was taken from patients with untreated non-malignant conditions including benign breast masses (n = 19), lupus (n = 11), liver cirrhosis (n = 5), benign prostatic hyperplasia (BPH) (n = 3), and viral infection (n = 1); or from healthy control volunteers (n = 76). CAMLs were isolated from whole peripheral blood by the CellSieve™ microfiltration technique and defined as enlarged, multinuclear cells with cytokeratin and/or CD45/CD14 positive. Results: CAMLs were found in 87% of all cancer patients regardless of stage, ~5.4 CAMLs/7.5mL blood. Specifically, CAMLs were found in 80% of Stage I, 90% Stage II, 89% Stage III, and 97% Stage IV patients. No CAMLs were found in any healthy controls, but were found in 26% of benign breast masses, 18% of lupus, 0% of BPH and 0% of cirrhosis. In total, CAML sensitivity in cancer vs healthy was 87% (CI95% 82-90%), specificity = 100% (CI95% 95-100%), PPV = 100% (CI95% 100%), NPV = 67% (CI95% 58-71%). CAML sensitivity in cancer vs benign was 87% (CI95% 82-90%), specificity = 80% (CI95% 64-91%), PPV = 97% (CI95% 95-98%), NPV = 43% (CI95% 35-51%). Conclusions: CAMLs, a Circulating Stromal Cell subtype, is a sensitive blood based biomarker found in all stages of cancer that is rare in non-malignant conditions and absent in healthy individuals.

e16065 Background: Estrogens, in addition to androgen may contribute to the progression of prostate cancer.The combination of bicalutamide, a non-steroidal anti-androgen, and raloxifene, a selective estrogen receptor modulator, has a synergistic effect on cell death of prostate cancer cell lines such as DU145 and PC3. We investigated the safety of combined treatment of bicalutamide and raloxifene on quality of life in patients affected by hormone-resistant prostate cancer. Methods: Eligibility requirements included metastatic hormone-resistant prostate cancer, Eastern Cooperative Oncology Group performance status of 0 or 1. Patients received the combination of bicalutamide, 50 mg, and raloxifene, 60 mg, daily in 28 day cycles for a maximum of 6 cycles. The primary endpoint was to describe the adverse event profile of combined treatment with bicalutamide and raloxifene. The secondary endpoint was to describe the quality of life of patients receiving the combination. Adverse events were graded by the investigator using the NCI Common Terminology Criteria for Adverse Events version 4.0 and the quality of life was assessed by the patient using aLinear Analog Scale Assessment (scale of 0-100). Serum levels of estradiol and testosterone were monitored during treatment. Results: Eighteen evaluable patients were included in the statistical analysis after an initial run-in safety cohort of six patients. Two patients completed 6 cycles per protocol, the remaining sixteen patients were taken off protocol after disease progression. Patients completed a median of 2 cycles. There were no grade 4 events and grade 3 adverse events consisted of hypertension (5.6%) and back pain (5.6%). Erectile dysfunction (grade 1) was the most common adverse event (77.8%). Patient assessment of quality of life (mental, physical, social, emotional, spiritual) did not reveal any statistically different changes after 2 cycles of treatment. An analysis of testosterone and estradiol levels will be reported. Conclusions: We conclude that combination of bicalutamide and raloxifene is well-tolerated. The combination of androgen and estrogen receptor blockade warrants further study for efficacy in hormone-resistant prostate cancer. Clinical trial information: NCT01050842.

4567 Background: Trials combining anti-PDL1 and anti-VEGF therapies for clear cell renal cell carcinoma (ccRCC) are underway; however the relationship between the expression of PDL1 and genes in the VEGF pathway is poorly understood. Using the Affymetrix platform, we observed an inverse association between the expression of PDL1 and key genes in the VEGF pathway. Herein, we validate this inverse association using an independent set of 100 primary ccRCC tumors. Methods: From our registry database we sampled 100 ccRCC tumors with varying PDL1 protein expression (0%-100%) determined by immunohistochemistry (IHC). We extracted RNA from FFPE slides and performed RT-PCR to quantify gene expression of PDL1, VEGF, VEGFR1, and VEGFR2. All genes were normalized to the POLR2a gene. We evaluated the association of PDL1 protein expression and VEGF gene expression using Spearman rank correlation. In addition, we employed a linear mixed effects model to compare the fold-change in expression of VEGF genes between PDL1 low (0-5%, n=68) and PDL1 high (>5%, n=32) tumors. Results: As expected, PDL1 protein expression positively correlates with PDL1 geneexpression (corr=0.42, p<0.001). Validating our array data, PDL1 protein expression inversely correlates with expression of key VEGF genes: VEGF (corr=-0.23, p=0.01), VEGFR1 (corr=-0.34, p<0.001), and VEGFR2 (corr=-0.23, p=0.01). In our dichotomized analysis, we noted significantly higher expression of VEGF genes in the PDL1 low compared to the PDL1 high group: VEGF (fold change=1.82, p<0.001), VEGFR1 (FC=2.63, p<0.001), and VEGFR2 (FC=2.13, p=0.001). Conclusions: We independently validate an inverse association between the expression of PDL1 and key genes in the VEGF pathway in primary ccRCC. If validated further in larger studies, the existence of an immune evasive and an angiogenic phenotype within ccRCC could inform current clinical trials targeting these two pathways. Ultimately, whether VEGF signaling affects PDL1 expression, or whether angiogenic or immune evasive phenotypes predict response to anti-PDL1, anti-VEGF, or a combination of the two therapies remains unclear.