Circulating and Imaging Biomarkers of Radium-223 Response in Metastatic Castration-Resistant Prostate Cancer.

PURPOSE: Radium-223 improves overall survival (OS) and reduces skeletal events in patients with bone metastatic castration-resistant prostate cancer (CRPC), but relevant biomarkers are lacking. We evaluated automated bone scan index (aBSI) and circulating tumor cell (CTC) analyses as potential biomarkers of prognosis and activity. PATIENTS AND METHODS: Patients with bone metastatic CRPC were enrolled on a prospective single-arm study of standard radium-223. 99mTc-MDP bone scan images at baseline, 2 months, and 6 months were quantitated using aBSI. CTCs at baseline, 1 month, and 2 months were enumerated and assessed for RNA expression of prostate cancer-specific genes using microfluidic enrichment followed by droplet digital polymerase chain reaction. RESULTS: The median OS was 21.3 months in 22 patients. Lower baseline aBSI and minimal change in aBSI (<+0.7) from baseline to 2 months were each associated with better OS (P = .00341 and P = .0139, respectively). The higher baseline CTC count of ≥5 CTC/7.5 mL was associated with worse OS (median, 10.1 v 32.9 months; P = .00568). CTCs declined at 2 months in four of 15 patients with detectable baseline CTCs. Among individual genes in CTCs, baseline expression of the splice variant AR-V7 was significantly associated with worse OS (hazard ratio, 5.20 [95% CI, 1.657 to 16.31]; P = .00195). Baseline detectable AR-V7, higher aBSI, and CTC count ≥5 CTC/7.5 mL continued to have a significant independent negative impact on OS after controlling for prostate-specific antigen or alkaline phosphatase. CONCLUSION: Quantitative bone scan assessment with aBSI and CTC analyses are prognostic markers in patients treated with radium-223. AR-V7 expression in CTCs is a particularly promising prognostic biomarker and warrants validation in larger cohorts.

Isoprenylated Coumarin Exhibits Anti-proliferative Effects in Pancreatic Cancer Cells Under Nutrient Starvation by Inhibiting Autophagy.

BACKGROUND/AIM: Due to the lack of early detection methods and effective treatments, pancreatic cancer has one of the lowest five-year survival rates among all cancers. We have previously identified novel isoprenylated coumarin compounds that exhibit preferential cytotoxicity against pancreatic adenocarcinoma cell line PANC-1 exclusively under glucose deprivation conditions. MATERIALS AND METHODS: Using cell cytotoxicity assays, we investigated the anti-proliferative mechanism of our most potent isoprenylated coumarin compound of the series, DCM-MJ-I-21, with respect to time, against two other pancreatic cancer cell lines, BxPC-3 and Capan-2. We used western blotting to quantify the autophagic flux influenced by our compound, autophagy inducers (starvation and Rapamycin), and autophagy inhibitors (chloroquine and wortmannin). RESULTS: We observed a clear dependence on glucose in DCM-MJ-I-21 in BxPC-3 and Capan-2 pancreatic cancer cell lines, suggesting that our compound targets a pathway shared by these cancer cell lines when glycolysis is not an option for survival. Our lead compound increased the conversion of LC3-I to LC3-II in PANC-1, similar to the effect of chloroquine, an autophagy inhibitor. In addition, Spautin-1, another autophagy inhibitor, showed almost the same anti-proliferative activities at the same concentration under nutrient-deprived conditions as our lead compound in both 2D and 3D cell cultures. CONCLUSION: Our lead isoprenylated coumarin compound induces selective pancreatic cancer cell death under nutrient-deprived conditions through inhibition of autophagy, potentially providing insights into new therapeutic options.

Immunotherapy Combined With Radiation Therapy for Genitourinary Malignancies.

Immunotherapy drugs have recently been approved by the Food and Drug Administration for the treatment of several genitourinary malignancies, including bladder cancer, renal cancer, and prostate cancer. Preclinical data and early clinical trial results suggest that immune checkpoint inhibitors can act synergistically with radiation therapy to enhance tumor cell killing at local irradiated sites and in some cases at distant sites through an abscopal effect. Because radiation therapy is commonly used in the treatment of genitourinary malignancies, there is great interest in testing the combination of immunotherapy with radiation therapy in these cancers to further improve treatment efficacy. In this review, we discuss the current evidence and biological rationale for combining immunotherapy with radiation therapy, as well as emerging data from ongoing and planned clinical trials testing the efficacy and tolerability of this combination in the treatment of genitourinary malignancies. We also outline outstanding questions regarding sequencing, dose fractionation, and biomarkers that remain to be addressed for the optimal delivery of this promising treatment approach.