ADXS31142 Immunotherapy ± Pembrolizumab Treatment for Metastatic Castration-Resistant Prostate Cancer: Open-Label Phase I/II KEYNOTE-046 Study.

BACKGROUND: ADXS31-142 is an attenuated Listeria monocytogenes-based immunotherapy targeting prostate-specific antigen (PSA), being evaluated as monotherapy and combined with pembrolizumab for metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: The 2-part phase I/II KEYNOTE-046 study enrolled men with mCRPC who have progressed after 2 or fewer prior systemic treatment regimens in the metastatic setting. In Part A, intravenous ADXS31-142 monotherapy was given every 3 weeks (q3w) to 3 dose-escalation cohorts. In Part B, ADXS31-142 (1 × 109 colony-forming units) plus pembrolizumab (200 mg) was administered intravenously q3w for 3 doses with a fourth pembrolizumab dose 3 weeks later (12-week cycles) for up to 24 months or until progression/toxicity. Endpoints included safety, overall response rate, progression-free survival (PFS), overall survival (OS), and immunogenicity. RESULTS: Fifty patients received ADXS31-142 alone (n = 13) or with pembrolizumab (n = 37). Among the 37 RECIST-evaluable patients (n = 8 Part A; n = 29 Part B), there were no objective responses. Median PFS was 2.2 months (95% CI: 0.8-7.4) with monotherapy and 5.4 months (95% CI: 2.3-7.9) with the combination; median OS was 7.8 months (95% CI: 4.4-18.5) and 33.7 months (95% CI: 15.4-not evaluable), respectively. Promising OS benefit was observed in combination-treated patients who had received prior docetaxel (16.0 months, 95% CI: 6.4-34.6; n = 20) and those with visceral metastasis (16.4 months, 95% CI 4.0-not evaluable; n = 11). All patients had ≥1 treatment-related adverse event, mostly grade 1/2 manageable events. No additive toxicity was observed with combination treatment. CONCLUSIONS: Combining ADXS31-142 with pembrolizumab was safe and well tolerated. The observed OS in mCRPC warrants further testing of this combination. CLINICAL TRIAL REGISTRATION: NCT02325557.

Neutral super-oxidised solutions are effective in killing P. aeruginosa biofilms.

Bacteria growing in biofilms can become up to 1000-fold more resistant to antibiotics and biocides as compared to their planktonic counterparts. As a result of this increased resistance, biofilms and biofilm-related infections cannot be effectively treated with conventional antibiotic therapy. The goal of this study was to determine the efficacy of three neutral pH, super-oxidised solutions (nSOSs, OIS-80, OIS-125, OIS-200, Microcyn Technology) varying in oxychlorine concentration (80, 125 and 200 ppm) against P. aeruginosa grown planktonically and as biofilms. Exposure for 20 s of exponential phase cells to any of the three solutions was sufficient to reduce viability by more than five logs. However, only exposure for 10 min to OIS-125 and OIS-200 for 10 min was sufficient to eradicate stationary phase P. aeruginosa cells. The efficacy of nSOSs on P. aeruginosa biofilms, grown to maturity in continuous flow tube reactors, was determined upon treatment up to 60 min. Viability pre- and post-treatment was determined by CFU counts. The effect of these solutions on P. aeruginosa biofilms and biofilm architecture was further visualised by confocal scanning laser microscopy and quantitatively analysed by COMSTAT. Under these experimental conditions, only OIS-125 and OIS-200 achieved a >3-log reduction and biofilm disaggregation within 30 min of exposure. Because OIS-125 and OIS-200 enhance the disaggregation of biofilms, their use in the treatment of surface-related biofilm infections deserves further investigation.

Effects of pH-neutral, super-oxidised solution on human dermal fibroblasts in vitro.

For the past 20 years, super-oxidised solutions (SOSs) have been shown to be potent antimicrobials and disinfectants via oxidative damage. However, the potential toxicity of SOSs on eukaryotic cells has not been documented in vitro. This is relevant because oxygen and chlorine reactive species may possibly induce ageing and irreversible cellular dysfunctions that eventually produce cell death. The present study investigates the cytotoxicity and oxidative stress induced by a novel, pH-neutral SOS (i.e. Microcyn, MCN) on young, primary diploid - human dermal fibroblast (HDF) cultures. For this purpose, hydrogen peroxide (HP) was used as a positive control of oxidative damage. When these solutions were used at concentrations indicated for wound care (i.e. undiluted MCN or 880 mM HP), HP was significantly more toxic than MCN. After 5 and 30 minutes of exposure, cell viability was 38% and 5%, respectively, in 880 mM HP-treated cells versus 75% and 70% in MCN-treated populations, respectively. HP induced both apoptosis and necrosis, whereas MCN induced only necrosis. Genotoxic and ageing studies were then conducted at sublethal HP concentrations as previously reported in the literature. Cellular DNA and RNA were partially degraded only in HDFs exposed to 500 microM HP for 30 minutes but not in those exposed to undiluted MCN. At this same concentration, HP induced the formation of 8-hydroxy-2'deoxyguanosine adducts in HDFs but this effect was neither observed in control- nor observed in MCN-treated cells. HDFs were further exposed to 5 microM HP or 10% MCN for 1 month. The expression of senescence-associated-beta-galactosidase was only significantly elevated in cells chronically exposed to 5 microM HP. Altogether, these results show that MCN is significantly less cytotoxic than antiseptic HP concentrations (i.e. 880 mM) and that, in vitro, it does not induce genotoxicity or accelerated ageing.

Progesterone effects on cell growth of U373 and D54 human astrocytoma cell lines.

Astrocytomas are the most frequent primary brain tumors and constitute a leading cause of cancer-related deaths. We studied the effects of progesterone and its antagonist, RU486, on cell growth of two human astrocytoma cell lines with different evolution grade (U373, grade III; and D54, grade IV). Progesterone receptor expression was determined by Western blot. The effects of different doses of progesterone and RU486 on cell number, cell cycle, and apoptosis were analyzed for five consecutive days. Progesterone (10 nM) significantly increased the number of D54 cells from the second day of culture, and the number of U373 cells on days 3-5. RU486 (10 muM) blocked progesterone effects in both astrocytoma cell lines. Interestingly, RU486 administered without progesterone significantly reduced the number of cells from the second day of culture in both cell lines. Progesterone increased S phase of cell cycle in U373 cells (61%, on day 5). RU486 blocked the effects of progesterone on cell cycle but administered alone did not significantly change cell cycle profile. DNA fragmentation (TUNEL) assay showed that the diminution in the number of astrocytoma cells produced by RU486 was not by apoptosis. Progesterone receptor isoforms were detected in both cell lines. Our data suggest that progesterone induces cell growth of human astrocytoma cell lines through the interaction with its nuclear receptor.

One-oligonucleotide method for constructing vectors for RNA interference.

AIM: To develop an easy, fast, automated, and inexpensive method for constructing short-hairpin-RNA cassettes for RNAi studies. METHODS: Using single oligonucleotides, a variety of DNA cassettes for RNAi vectors were constructed in only few minutes in an automated manner. The cassettes, targeting the eGFP, were cloned into plasmids driven by RNA polymerase III promoter H1. Then, the plasmids were transfected into HeLa cells that were later infected with a recombinant adenovirus encoding the eGFP gene. The level of eGFP fluorescence was evaluated by confocal imaging and flow cytometry. RESULTS: The plasmids constructed with the DNA cassettes made by the one-oligonucleotide method inhibited eGFP with different potencies, ranging from 55% to 75%. CONCLUSION: By using the method reported here, it is possible to simultaneously construct hundreds of different DNA cassettes for RNAi experiments in an inexpensive, automated way. This method will facilitate functional genomics studies on mammalian cells.