Pathobiology of cigarette smoke-induced invasive cancer of the renal pelvis and its prevention by vitamin C

Urothelial cancer of the renal pelvis (CRP) is predominantly associated with cigarette smoking. However, the molecular pathogenesis of initiation and progression of cigarette smoke (CS)-induced CRP is unknown. Majority of CRP is high grade and high stage at presentation and has a high recurrence rate even after surgery. Earlier we reported that prolonged treatment (24 weeks) of a guinea pig model with p-benzoquinone (p-BQ), a product of CS in vivo, produced carcinoma in situ in the renal pelvis, a noninvasive cancer. Since CS is known to induce invasive cancer, we investigated the effect of CS exposure to the guinea pigs. We observed that CS exposure for a short period (18 weeks) produced invasive tumor (pT1). pT1 was confirmed by immunohistochemistry showing increased immunoexpression of nuclear p53 indicating p53 mutation, aberrant CK20, increased Ki-67 and uniformly negative labeling of CD44. As observed earlier with p-BQ treatment, the initial events of CS exposure were oxidative damage and apoptosis that was followed by persistent signaling through EGFR and MAP kinase pathway. CS exposure also caused hyperphosphorylation of pRb, activation of cyclin E and cell cycle deregulation leading to infiltration of epithelial cells in lamina propria of the renal pelvis resulting in pT1 tumor. Oral supplementation of vitamin C (30 mg/kg guinea pig/day) inhibited oxidative damage and apoptosis and holistically prevented the tumor formation. We consider that our preclinical findings on the intake of adequate vitamin C, along with intense advice for cessation of smoking, will be helpful for the prevention of CS-induced CRP in smokers. Keywords: Invasive cancer of the renal pelvis, Cigarette smoke, Vitamin C, Oxidative damage, Persistent EGFR signaling, Cell cycle deregulatio

p-Benzoquinone initiates non-invasive urothelial cancer through aberrant tyrosine phosphorylation of EGFR, MAP kinase activation and cell cycle deregulation: Prevention by vitamin C

According to WHO classification system, non-invasive urothelial carcinoma represents urothelial carcinoma in situ (CIS) and dysplasia. Dysplastic urothelium often progresses to CIS that further advances to urothelial carcinoma (UC). The strongest risk factor for UC is cigarette smoking. However, the pathogenesis of cigarette smoke (CS)-induced UC is poorly understood. Earlier we had shown that p-benzoquinone (p-BQ), a major toxic quinone derived from p-benzosemiquinone of CS in vivo, is a causative factor for various CS-induced diseases. Here, using a guinea pig model we showed that prolonged treatment with p-BQ led to non-invasive UC, specifically carcinoma in situ (CIS) of the renal pelvis and dysplasia in the ureter and bladder. The mechanisms of carcinogenesis were p-BQ-induced oxidative damage and apoptosis that were later suppressed and followed by activation of epidermal growth factor receptor, aberrant phosphorylation of intracellular tyrosine residues, activation of MAP kinase pathway and persistent growth signaling. This was accompanied by deregulation of cell cycle as shown by marked decrease in the expression of p21waf1/cip1 and cyclin D1 proteins as well as hyperphosphorylation of pRb. UC has been characterised by histopathology and immunohistochemistry showing aberrant CK20, increased Ki-67, and marked p53 nuclear immunopositivity with uniformly negative labelling of CD44. Oral supplementation of vitamin C (30 mg/kg body weight/day) prevented CIS of the renal pelvis and dysplasia in the ureter and bladder. Since majority of non-invasive UC progresses to invasive cancer with increased risk of mortality, our preclinical study might help to devise effective strategies for early intervention of the disease. Abbreviations: Bax, Bcl-2, CS, DNPH, GAPDH, IARC, p-BQ, p-BSQ, PAHs, PBS, ROS, SDS PAGE, TUNEL, WHO, UC, CIS, EGFR, MAPK, Keywords: p-Benzoquinone, Carcinoma in situ, Dysplasia, Aberrant EGFR activation, Cell cycle deregulation, Vitamin

Relationship between androgen biosynthesis linked to 3βHSD1 and resistance to radiotherapy: A germline biomarker for combined androgen blockade with radiation in high-risk prostate cancer

e17084 Background: Around 50% of men with advanced prostate cancer (PCa) have at least one germline copy of the adrenal-permissive (1245C) HSD3B1 allele. This allele leads to higher levels of the steroid biosynthesis enzyme, 3β-hydroxysteroid dehydrogenase (3βHSD1). Inheriting this allele is linked to worse outcomes in men with advanced PCa. To determine if (1245C) HSD3B1 could be causing early resistance to combined androgen deprivation and radiotherapy in localized PCa, we studied its role in modulating radioresistance. Methods: PCa cell lines were used to investigate the reciprocal effects of 3βHSD1 knockdown and overexpression in intrinsically high and low 3βHSD1 lines, respectively. PCa xenografts were used to confirm the results in vivo. The connection between androgen receptor (AR) expression and elevated DNA Damage Response (DDR) gene expression was validated using transcriptomic data from 680 radical prostatectomy specimens The ability of enzalutamide, a non-steroidal anti-androgen, to restore radiosensitivity in 1245C expressing lines was interrogated in vitro and in vivo. Results: 1245C HSD3B1 expressing PCa lines displayed increased clonogenic survival after ionizing radiation. Effects were dependent on the 3βHSD1 substrate, DHEA, confirming intratumoral androgen metabolism was required for radioresistance. Resistant lines showed enhanced DNA double-strand break (DSB) repair and heightened DDR gene expression. PCa xenografts with 1245C HSD3B1 were similarly more resistant to radiation using murine models that faithfully mimic human adrenal physiology. A correlation between AR expression and increased DDR gene expression was confirmed in 680 patient samples. Enzalutamide pretreatment resulted in a decrease in DSB repair ability and re-sensitized 1245C HSD3B1 PCa cells to radiation. Conclusions: 1245C HSD3B1 fuels prostate cancer treatment resistance by elevating regional androgen biosynthesis from adrenal steroid precursors, leading to DDR gene overexpression and enhanced DNA DSB repair kinetics. This work supports clinical validation of biomarker informed selective intensification strategies, e.g., combined androgen blockade, for high-risk men with the 1245C HSD3B1 allele receiving curative intent radiotherapy

Intratumoral androgen biosynthesis associated with 3β-hydroxysteroid dehydrogenase 1 promotes resistance to radiotherapy in prostate cancer

Half of all men with advanced prostate cancer (PCa) inherit at least 1 copy of an adrenal-permissive HSD3B1 (1245C) allele, which increases levels of 3β-hydroxysteroid dehydrogenase 1 (3βHSD1) and promotes intracellular androgen biosynthesis. Germline inheritance of the adrenally permissive allele confers worse outcomes in men with advanced PCa. We investigated whether HSD3B1 (1245C) drives resistance to combined androgen deprivation and radiotherapy. Adrenally permissive 3βHSD1 enhanced resistance to radiotherapy in PCa cell lines and xenograft models engineered to mimic the human adrenal/gonadal axis during androgen deprivation. The allele-specific effects on radiosensitivity were dependent on availability of DHEA, the substrate for 3βHSD1. In lines expressing the HSD3B1 (1245C) allele, enhanced expression of DNA damage response (DDR) genes and more rapid DNA double-strand break (DSB) resolution were observed. A correlation between androgen receptor (AR) expression and increased DDR gene expression was confirmed in 680 radical prostatectomy specimens. Treatment with the nonsteroidal antiandrogen enzalutamide reversed the resistant phenotype of HSD3B1 (1245C) PCa in vitro and in vivo. In conclusion, 3βHSD1 promotes prostate cancer resistance to combined androgen deprivation and radiotherapy by upregulating DNA DSB repair. This work supports prospective validation of early combined androgen blockade for high-risk men harboring the HSD3B1 (1245C) allele

Intratumoral androgen biosynthesis associated with 3[beta]-hydroxysteroid dehydrogenase 1 promotes resistance to radiotherapy in prostate cancer

Half of all men with advanced prostate cancer (PCa) inherit at least 1 copy of an adrenal-permissive HSD3B1 (1245C) allele, which increases levels of 3[beta]-hydroxysteroid dehydrogenase 1 (3[beta]HSD1) and promotes intracellular androgen biosynthesis. Germline inheritance of the adrenally permissive allele confers worse outcomes in men with advanced PCa. We investigated whether H5D3S7 (1245C) drives resistance to combined androgen deprivation and radiotherapy. Adrenally permissive 3[beta]HSD1 enhanced resistance to radiotherapy in PCa cell lines and xenograft models engineered to mimic the human adrenal/gonadal axis during androgen deprivation. The allele-specific effects on radiosensitivity were dependent on availability of DHEA, the substrate for 3[beta]HSD1. In lines expressing the HSD3B1 (1245C) allele, enhanced expression of DNA damage response (DDR) genes and more rapid DNA double-strand break (DSB) resolution were observed. A correlation between androgen receptor (AR) expression and increased DDR gene expression was confirmed in 680 radical prostatectomy specimens. Treatment with the nonsteroidal antiandrogen enzalutamide reversed the resistant phenotype of HSD3B1 (1245C) PCa in vitro and in vivo. In conclusion, 3[beta]HSD1 promotes prostate cancer resistance to combined androgen deprivation and radiotherapy by upregulating ?NA DSB repair. This work supports prospective validation of early combined androgen blockade for high-risk men harboring the HSD3B1 (1245C) allele.Academi