Deficiency of DNA repair nuclease ERCC1-XPF promotes prostate cancer progression in a tissue recombination model

Increased ERCC1 expression is linked to chromosomal aberrations and adverse tumor biology in prostate cancer

BACKGROUND

Animal model experiments have suggested a role of the DNA repair protein ERCC1 (Excision Repair Cross-Complementation Group 1) in prostate cancer progression.

METHODS

To better understand the impact of ERCC1 protein expression in human prostate cancer, a preexisting tissue microarray (TMA) containing more than 12,000 prostate cancer specimens was analyzed by immunohistochemistry and data were compared with tumor phenotype, PSA recurrence and several of the most common genomic alterations (TMPRSS2:ERG fusions: deletions of PTEN, 6q, 5q, 3p).

RESULTS

ERCC1 staining was seen in 64.7% of 10,436 interpretable tissues and was considered weak in 37.1%, moderate in 22.6% and strong in 5% of tumors. High-level ERCC1 staining was linked to advanced pT stage, high Gleason grade, positive lymph nodes, high pre-operative serum PSA, and positive surgical margin status (p < 0.0001 each). High ERCC1 expression was strongly associated with an elevated risk of PSA recurrence (p < 0.0001). This was independent of established prognostic features. A subgroup analysis of cancers defined by comparable quantitative Gleason grades revealed that the prognostic impact was mostly driven by low-grade tumors with a Gleason 3 + 3 or 3 + 4 (Gleason 4: ≤5%). High ERCC1 expression was strongly associated with the presence of genomic alterations and expression levels increased with the number of deletions present in the tumor. These latter data suggest a functional relationship of ERCC1 expression with genomic instability.

CONCLUSION

The results of our study demonstrate that expression of ERCC1 - a potential surrogate for genomic instability - is an independent prognostic marker in prostate cancer with particular importance in low-grade tumors.

Higher expression of XPF is a critical factor in intrinsic chemotherapy resistance of human renal cell carcinoma

Human renal cancer is extremely resistant to chemotherapy and radiation therapy. This clinical characteristic reduces the efficacy of chemotherapeutic agents in the treatment of recurrence or metastasis following surgical resection. Understanding the mechanism of chemotherapy resistance in renal cell carcinoma remains a significant challenge. In this study, we have shown that varied level of XPF expression was organ-tissue specific by comparing human renal cancer, bladder cancer, testicular cancer and their normal tissue counterparts, respectively. The expression of XPF was significantly higher in renal cancer than in bladder cancer and testicular cancer and correlated with the clinical characteristic of their chemotherapeutics sensitivity. These novel findings proposed that the intrinsic chemoresistance of human renal cell carcinomas might be derived from the high level of XPF expression. In a panel of five cancer cell lines, decreasing cisplatin sensitivity correlated with increasing levels of XPF expression. Knockdown of XPF expression not only increased sensitivity of renal carcinoma cells to cisplatin treatment by affecting the DNA damage response, including DNA repair, cell cycle regulation and apoptosis, but also increased senescence of renal cancer cell. Furthermore, experiment in vivo confirmed that silenced XPF significantly increased the sensitivity and survival following treatment with cisplatin in xenograft mice bearing renal cell tumor. These findings firstly uncover a partial mechanism of intrinsic chemoresistance in renal cancer and may provide a new approach to break through the obstacle of intrinsic chemoresistance by targeting the XPF protein with a potential new inhibitor.

Single nucleotide polymorphisms in DNA repair genes as risk factors associated to prostate cancer progression

Background

Besides serum levels of PSA, there is a lack of prostate cancer specific biomarkers. It is need to develop new biological markers associated with the tumor behavior which would be valuable to better individualize treatment. The aim of this study was to elucidate the relationship between single nucleotide polymorphisms (SNPs) in genes involved in DNA repair and prostate cancer progression.

Methods

A total of 494 prostate cancer patients from a Spanish multicenter study were genotyped for 10 SNPs in XRCC1, ERCC2, ERCC1, LIG4, ATM and TP53 genes. The SNP genotyping was made in a Biotrove OpenArray® NT Cycler. Clinical tumor stage, diagnostic PSA serum levels, and Gleason score at diagnosis were obtained for all participants. Genotypic and allelic frequencies were determined using the web-based environment SNPator.

Results

SNPs rs11615 (ERCC1) and rs17503908 (ATM) appeared as risk factors for prostate cancer aggressiveness. Patients wild homozygous for these SNPs (AA and TT, respectively) were at higher risk for developing cT2b – cT4 (OR = 2.21 (confidence interval (CI) 95% 1.47 – 3.31), p < 0.001) and Gleason scores ≥ 7 (OR = 2.22 (CI 95% 1.38 – 3.57), p < 0.001), respectively. Moreover, those patients wild homozygous for both SNPs had the greatest risk of presenting D’Amico high-risk tumors (OR = 2.57 (CI 95% 1.28 – 5.16)).

Conclusions

Genetic variants at DNA repair genes are associated with prostate cancer progression, and would be taken into account when assessing the malignancy of prostate cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-014-0143-0) contains supplementary material, which is available to authorized users.

Emerging roles of Jab1/CSN5 in DNA damage response, DNA repair, and cancer

Jab1/CSN5 is a multifunctional protein that plays an important role in integrin signaling, cell proliferation, apoptosis, and the regulation of genomic instability and DNA repair. Dysregulation of Jab1/CSN5 activity has been shown to contribute to oncogenesis by functionally inactivating several key negative regulatory proteins and tumor suppressors. In this review, we discuss our current understanding of the relationship between Jab1/CSN5 and DNA damage and summarize recent findings regarding opportunities for and challenges to therapeutic intervention.