Expanding the Prostate Cancer Cell Line Repertoire with ACRJ-PC28, an AR-negative Neuroendocrine Cell Line Derived From an African-Caribbean Patient

Abstract

Prostate cancer cell lines from diverse backgrounds are important to addressing disparities in prostate cancer incidence and mortality rates among Black men. ACRJ-PC28 was developed from a transrectal needle biopsy and established via inactivation of the CDKN2A locus and simultaneous expression of human telomerase. Characterization assays included growth curve analysis, immunoblots, IHC, three-dimensional cultures, immunofluorescence imaging, confocal microscopy, flow cytometry, whole-genome sequencing (WGS), and RNA sequencing (RNA-seq). ACRJ-PC28 has been passaged more than 40 times in vitro over 10 months with a doubling time of 45 hours. Short tandem repeat profiling confirmed the novelty and human origin of the cell line. RNA-seq confirmed the expression of prostate specific genes alpha-methylacyl-CoA racemase (AMACR) and NKX3.1 and neuroendocrine specific markers synaptophysin and enolase 2 (ENO2) and IHC confirmed the presence of AMACR. Immunoblots indicated the cell line is of basal-luminal type; expresses p53 and pRB and is androgen receptor (AR) negative. WGS confirmed the absence of exonic mutations and the presence of intronic variants that appear to not affect function of AR, p53, and pRB. RNA-seq data revealed numerous TP53 and RB1 mRNA splice variants and the lack of AR mRNA expression. This is consistent with retention of p53 function in response to DNA damage and pRB function in response to contact inhibition. Soft agar anchorage-independent analysis indicated that the cells are transformed, confirmed by principal component analysis where ACRJ-PC28 cells cluster alongside other prostate cancer tumor tissues, yet was distinct. The novel methodology described should advance prostate cell line development, addressing the disparity in prostate cancer among Black men. Significance: Cell line development continues to attract less than 10% success rate. More than 98% of prostate cancer cell lines are from White men. This may contribute to the poorer response by Black men with prostate cancer to therapy compared with White men with prostate cancer, increasing overall survivorship among White men. The methodology described here to develop ACRJ-PC28, should advance the presence of Black prostate cancer cell lines thereby addressing prostate cancer disparity.