Prostatic chronic inflammation and prostate cancer risk at baseline random biopsy: Analysis of predictors

Inflammation and Prostate Cancer: Pathological Analysis from Pros-IT CNR 2

BACKGROUND

Extensive research effort has been devoted to investigating the link between inflammation and PCa. However, this relationship remains unclear and controversial. The aim of our multi-center study was to investigate this association by histologically evaluating the distribution of PI and PCA in prostate biopsy cores from patients of eight referral centers in Italy.

RESULTS

We evaluated 2220 cores from 197 patients; all the frustules were re-evaluated by dedicated pathologists retrospectively. Pathologists assigned IRANI scores and determined the positions of PIs; pathologists also re-evaluated the presence of PCa and relative ISUP grade. PCa was recorded in 749/2220 (33.7%). We divided this sample into a PCa PI group (634/749 cores [84.7%]) and a non-PCa + PI group (1157/1471 cores [78.7%]). We observed a statistically significant difference in the presence of inflammation among cores with cancer (p < 0.01). Moreover, periglandular inflammation was higher in the cores with neoplasia, while stromal inflammation was higher in cores without neoplasia (38.5% vs. 31.1% and 55.4% vs. 63.5% p < 0.01).

CONCLUSIONS

In our experience, there is evidence of an association between PI and PCa at a tissue level. Further studies are needed to confirm our findings and to identify patients who might benefit from target therapies to prevent PCa occurrence and/or progression.

Chronic IL-1 exposure drives LNCaP cells to evolve androgen and AR independence

Chronic inflammation promotes prostate cancer (PCa) initiation and progression. We previously reported that acute intereluekin-1 (IL-1) exposure represses androgen receptor (AR) accumulation and activity, providing a possible mechanism for IL-1-mediated development of androgen- and AR-independent PCa. Given that acute inflammation is quickly resolved, and chronic inflammation is, instead, co-opted by cancer cells to promote tumorigenicity, we set out to determine if chronic IL-1 exposure leads to similar repression of AR and AR activity observed for acute IL-1 exposure and to determine if chronic IL-1 exposure selects for androgen- and AR-independent PCa cells. We generated isogenic sublines from LNCaP cells chronically exposed to IL-1α or IL-1β. Cells were treated with IL-1α, IL-1β, TNFα or HS-5 bone marrow stromal cells conditioned medium to assess cell viability in the presence of cytotoxic inflammatory cytokines. Cell viability was also assessed following serum starvation, AR siRNA silencing and enzalutamide treatment. Finally, RNA sequencing was performed for the IL-1 sublines. MTT, RT-qPCR and western blot analysis show that the sublines evolved resistance to inflammation-induced cytotoxicity and intracellular signaling and evolved reduced sensitivity to siRNA-mediated loss of AR, serum deprivation and enzalutamide. Differential gene expression reveals that canonical AR signaling is aberrant in the IL-1 sublines, where the cells show constitutive PSA repression and basally high KLK2 and NKX3.1 mRNA levels and bioinformatics analysis predicts that pro-survival and pro-tumorigenic pathways are activated in the sublines. Our data provide evidence that chronic IL-1 exposure promotes PCa cell androgen and AR independence and, thus, supports CRPCa development.