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Activation of some signaling pathways can promote cell survival and have a negative impact on tumor response to radiotherapy. Here, the role of differences in expression levels of genes related to the poly(ADP-ribose) polymerase-1 (PARP-1), heat shock protein 90 (Hsp90), B-cell lymphoma 2 (Bcl-2), and phosphoinositide 3-kinase (PI3K) pathways in the survival or death of cells following X-ray exposure was investigated. Eight human cell cultures (MCF-7 and MDA-MB-231: breast cancers; MCF-12A: apparently normal breast; A549: lung cancer; L132: normal lung; G28, G44 and G112: glial cancers) were irradiated with X-rays. The colony-forming and real-time PCR based on a custom human pathway RT2 Profiler PCR Array assays were used to evaluate cell survival and gene expression, respectively. The surviving fractions at 2 Gy for the cell lines, in order of increasing radioresistance, were found to be as follows: MCF-7 (0.200 ± 0.011), G44 (0.277 ± 0.065), L132 (0.367 ± 0.023), MDA-MB-231 (0.391 ± 0.057), G112 (0.397 ± 0.113), A549 (0.490 ± 0.048), MCF-12A (0.526 ± 0.004), and G28 (0.633 ± 0.094). The rank order of radioresistance at 6 Gy was: MCF-7 < L132 < G44 < MDA-MB-231 < A549 < G28 < G112 < MCF-12A. PCR array data analysis revealed that several genes were differentially expressed between irradiated and unirradiated cell cultures. The following genes, with fold changes: BCL2A1 (21.91), TP53 (8743.75), RAD51 (11.66), FOX1 (65.86), TCP1 (141.32), DNAJB1 (3283.64), RAD51 (51.52), and HSPE1 (12887.29) were highly overexpressed, and BAX (–127.21), FOX1 (–81.79), PDPK1 (–1241.78), BRCA1 (–8.70), MLH1 (–12143.95), BCL2 (–18.69), CCND1 (–46475.98), and GJA1 (–2832.70) were highly underexpressed in the MDA-MB-231, MCF-7, MCF-12A, A549, L132, G28, G44, and G112 cell lines, respectively. The radioresistance in the malignant A549 and G28 cells was linked to upregulation in the apoptotic, DNA repair, PI3K, and Hsp90 pathway genes BAG1, MGMT, FOXO1, and DNAJA1, respectively, and inhibition of these genes resulted in significant radiosensitization. Targeting BAG1, MGMT, FOXO1, and DNAJA1 with specific inhibitors might effectively sensitize radioresistant tumors to radiotherapy. [ABSTRACT FROM AUTHOR]

Conventional chemotherapy has had very limited success in the control of hormone-refractory prostate cancer. Methylxanthine derivatives, such as pentoxifylline (PTX), are known to abrogate the G2 block and enhance the toxicity of ionising irradiation and chemotherapeutic agents. It is now also established that late addition of the cytotoxic drug after irradiation under conditions of G2 block abrogation sensitises human tumour cells for cytotoxins. Here we assess whether the chemosensitivity of prostate tumour cell lines can be enhanced by the application of a low dose of drug in conjunction with a G2 block abrogator. Prostate cell lines DU145, BM1604 and LNCaP were irradiated with 7 Gy 60Co γ-irradiation. A sub-toxic (2 mM) dose of pentoxifylline and a cytotoxic drug were added at maximum expression of the G2 cell cycle block and cell survival was determined by colony assay. Cisplatin, etoposide and vinblastine were tested at a toxic dose of 10% (TD10). In the TP53 mutant cell lines, DU145 and BM1604, dose enhancement factors (EFs) were found to be in the region of 4.20 for cisplatin, 3.70 for vinblastine, and 3.20 for etoposide. In the TP53 wild-type cell line, LNCaP, the enhancement factors were low and in the region of 1.20 for cisplatin, vinblastine and etoposide. It is clear, therefore, that toxicity enhancement factors (EFs) are greater in the TP53 mutant cell lines, DU145 and BM1604, than in the TP53 wild-type cell line, LNCaP. The results indicate that a significant enhancement of drug toxicity can be obtained if the cytotoxic drug is given under conditions of G2 block abrogation. The sensitisation of prostate cancer cells to cytotoxic drugs is particularly high in radiation-resistant TP53 mutant tumour cells. Drugs which abrogate G2 block have the potential to enhance the therapeutic index and therefore reduce the toxicity of chemotherapy drugs. [ABSTRACT FROM AUTHOR]

The objective of this study was to validate the results from our published work and to test the robustness of our unique malignancy index as a (non-invasive) predictor of prostate cancer in fresh blood samples obtained from patients diagnosed with prostate cancer (PCa), benign prostatic hyperplasia (BPH), and healthy volunteers (Controls). The malignancy index was obtained by dividing the product of three biomarker values, [urokinase plasminogen activator (uPA), plasminogen activator inhibitor type-1 (PAI-1), and prostate-specific antigen (PSA)], by the age of the patient/healthy volunteer, using enzyme-linked immunosorbent (ELISA) assay methodology. The results confirmed earlier findings that the malignancy index discriminates prostate cancer from non-prostate cancer. The index significantly separated the PCa group from the Control group with values of 0.0701 (n=54) and 0.0007 (n=47), respectively, by a factor of 100. The malignancy index of the small BPH cohort was found to be 0.0016 (n=20), differing by a factor of 44 from the Control group. When data from the earlier study and the current study data were collectively analyzed, the index again significantly separated the PCa group from the Control group by a factor of 15, with values of 0.0624 (n=125) and 0.0042 (n=110), respectively. However, the same could not be said of the BPH data since the sample size (n=20) was well below par, for comparison. In the initial blood study, the PCa group was significantly separated from the Control group by a factor of 8.5. The data presented here concur with findings in needle biopsies and transurethral resection tissue, reported elsewhere (Bohm et al., 2013; Akudugu et al., 2015). At this preliminary stage, the malignancy index has potential and merit as a prostate cancer biomarker.

No unambiguous role of the involvement of uroplasminogen activator (uPA) and plasminogen activator inhibitor type-1 (PAI-1) in prostate cancer has emerged, with current evidence suggesting that neither biomarker is likely of significant clinical value, save as an overall contributor. In this study, we attempt to discriminate prostate cancer from non-cancer in a cohort of plasma samples, using the Imubind ELISA assay. In this cohort, PAI-1 levels are higher in prostate cancer patients than healthy donors; uPA levels are higher in healthy donors than prostate cancer patients; and the uPA/PAI-1 ratio is higher in healthy donors than in prostate cancer patients. To date, and across three prostate sample types, i.e. transurethral resection tissue, needle biopsies, and blood plasma, data have been disparate. Given the inconsistency, a malignancy index was created by dividing the product of three biomarkers [uPA, PAI-1, and prostate specific antigen (PSA)] by the age of the patient/donor. The malignancy index clearly distinguishes prostate disease from non-disease in peripheral blood plasma samples (P=0.0127), concurring with findings in core needle biopsies and transurethral resection tissue, reported elsewhere. This is an important finding given the gravity of prostate cancer and the legions of over-diagnosed and over-treated men worldwide.

Adrenal C 19 steroids serve as precursors to active androgens in the prostate. Androstenedione (A4), 11β-hydroxyandrostenedione (11OHA4) and 11β-hydroxytestosterone (11OHT) are metabolised to potent androgen receptor (AR) agonists, dihydrotestosterone (DHT), 11-ketotestosterone (11KT) and 11-ketodihydrotestosterone (11KDHT). The identification of 11OHA4 metabolites, 11KT and 11KDHT, as active androgens has placed a new perspective on adrenal C11-oxy C 19 steroids and their contribution to prostate cancer (PCa). We investigated adrenal androgen metabolism in normal epithelial prostate (PNT2) cells and in androgen-dependent prostate cancer (LNCaP) cells. We also analysed steroid profiles in PCa tissue and plasma, determining the presence of the C 19 steroids and their derivatives using ultra-performance liquid chromatography (UHPLC)- and ultra-performance convergence chromatography tandem mass spectrometry (UPC 2 -MS/MS). In PNT2 cells, sixty percent A4 (60%) was primarily metabolised to 5α-androstanedione (5αDIONE) (40%), testosterone (T) (10%), and androsterone (AST) (10%). T (30%) was primarily metabolised to DHT (10%) while low levels of A4, 5αDIONE and 3αADIOL (≈20%) were detected. Conjugated steroids were not detected and downstream products were present at <0.05μM. Only 20% of 11OHA4 and 11OHT were metabolised with the former yielding 11keto-androstenedione (11KA4), 11KDHT and 11β-hydroxy-5α-androstanedione (11OH-5αDIONE) and the latter yielding 11OHA4, 11KT and 11KDHT with downstream products <0.03μM. In LNCaP cells, A4 (90%) was metabolised to AST-glucuronide via the alternative pathway while T was detected as T-glucuronide with negligible conversion to downstream products. 11OHA4 (80%) and 11OHT (60%) were predominantly metabolised to 11KA4 and 11KT and in both assays more than 50% of 11KT was detected in the unconjugated form. In tissue, we detected C11-oxy C 19 metabolites at significantly higher levels than the C 19 steroids, with unconjugated 11KDHT, 11KT and 11OHA4 levels ranging between 13 and 37.5ng/g. Analyses of total steroid levels in plasma showed significant levels of 11OHA4 (≈230-440nM), 11KT (≈250-390nM) and 11KDHT (≈19nM). DHT levels (<0.14nM) were significantly lower. In summary, 11β-hydroxysteroid dehydrogenase type 2 activity in PNT2 cells was substantially lower than in LNCaP cells, reflected in the conversion of 11OHA4 and 11OHT. Enzyme substrate preferences suggest that the alternate pathway is dominant in normal prostate cells. Glucuronidation activity was not detected in PNT2 cells and while all T derivatives were efficiently conjugated in LNCaP cells, 11KT was not. Substantial 11KT levels were also detected in both PCa tissue and plasma. 11OHA4 therefore presents a significant androgen precursor and its downstream metabolism to 11KT and 11KDHT as well as its presence in PCa tissue and plasma substantiate the importance of this adrenal androgen., (Copyright © 2016 Elsevier Ltd. All rights reserved.)