Different splicing isoforms of ERCC1 affect the expression of its overlapping genes CD3EAP and PPP1R13L, and indicate a potential application in non-small cell lung cancer treatment

A systematic review of inter-individual differences in the DNA repair processes involved in melphalan monoadduct repair in relation to treatment outcomes

PURPOSE

Melphalan is a bifunctional alkylating agent that elicits its cytotoxic activity by rapidly forming an initial DNA monoadduct, which then produces an inter-strand crosslink. Most studies exploring the role of inherited differences in DNA repair and melphalan outcomes focus on inter-strand crosslink repair, however, monoadduct repair likely plays a key role since it minimises the ultimate production of these crosslinks. The purpose of this systematic review was to assess evidence of an association between variation in monoadduct repair pathways and melphalan response.

METHODS

A literature search was undertaken using Medline, Embase, Scopus and PubMed databases. Duplicates were removed and only full-text articles were included. To be included for critique in this systematic review, articles were assessed for relevance using strict inclusion/exclusion criteria.

RESULTS

Fourteen studies were identified that involved patients treated with melphalan, however, in 3, only a minority of the cohort received melphalan. Across the remaining 11 studies, 61 genes/proteins in DNA monoadduct repair pathways were assessed. Both germline SNP (CDKN1A, ERCC1, ERCC2, ERCC4, ERCC6, EXO1, MLH1, MNAT1, MUTYH, PARP4, PCNA, POLE, POLR1G, RAD23B, RFC1, RFC3, RPA1, RPA3, TREX1, UNG, XPC, XRCC1) and somatic expression (CDKN1A, PARP1, PCNA, MGMT, RECQL, RFC5) were associated with melphalan outcomes in ≥ 1 study.

CONCLUSION

It appears that inherited germline differences in monoadduct repair genes may be a risk factor for poor outcomes. However, the diversity of study design, patient cohorts, genes assessed and lack of replication, preclude any meta-analysis. Further prospective studies are required to validate these findings.

A gene-based risk score model for predicting recurrence-free survival in patients with hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) remains the most frequent liver cancer, accounting for approximately 90% of primary liver cancers worldwide. The recurrence-free survival (RFS) of HCC patients is a critical factor in devising a personal treatment plan. Thus, it is necessary to accurately forecast the prognosis of HCC patients in clinical practice.

METHODS

Using The Cancer Genome Atlas (TCGA) dataset, we identified genes associated with RFS. A robust likelihood-based survival modeling approach was used to select the best genes for the prognostic model. Then, the GSE76427 dataset was used to evaluate the prognostic model's effectiveness.

RESULTS

We identified 1331 differentially expressed genes associated with RFS. Seven of these genes were selected to generate the prognostic model. The validation in both the TCGA cohort and GEO cohort demonstrated that the 7-gene prognostic model can predict the RFS of HCC patients. Meanwhile, the results of the multivariate Cox regression analysis showed that the 7-gene risk score model could function as an independent prognostic factor. In addition, according to the time-dependent ROC curve, the 7-gene risk score model performed better in predicting the RFS of the training set and the external validation dataset than the classical TNM staging and BCLC. Furthermore, these seven genes were found to be related to the occurrence and development of liver cancer by exploring three other databases.

CONCLUSION

Our study identified a seven-gene signature for HCC RFS prediction that can be used as a novel and convenient prognostic tool. These seven genes might be potential target genes for metabolic therapy and the treatment of HCC.

AC138128.1 an Intronic lncRNA originating from ERCC1 Implies a Potential Application in Lung Cancer Treatment

Lung cancer is one of the most devastating tumors with a high incidence and mortality worldwide. Polymorphisms and expression of ERCC1 commonly predicted the occurrence and prognosis of lung cancer. However, few studies have focused on long non-coding RNAs related to ERCC1 though some studies reminded the importance of its post-transcriptional regulation. In the present study, an intronic lncRNA AC138128.1 originated from ERCC1 was firstly identified in microarray chip and database, and its possibility as a novel biomarker to predict lung cancer treatment was further discussed. Firstly, the qRT-PCR data showed that AC138128.1 expression was much lower in lung cancer comparing with its para-cancer tissues, which further analyzed by ROC curve. Similarly, the difference was also verified in 16HBE, A549 and LK₂ cells. Then AC138128.1 expression was found to have an increasing trend in a dose or time-dependent manner after cisplatin treatment. Finally, the subcellular distribution of AC138128.1 reminded that AC138128.1 was mainly expressed in the nucleus. Interestingly a positive relationship between AC138128.1 and ERCC1 expression was only found in cancer tissues, which reminded AC138128.1 may be involved in the regulation of ERCC1. Therefore, as a preliminary exploration of the lncRNA originated from ERCC1, the present study suggested AC138128.1 is of potential value in predicting platinum analogue benefit in lung cancer.

Rs3212986 polymorphism, a possible biomarker to predict smoking-related lung cancer, alters DNA repair capacity via regulating ERCC1 expression

Single nucleotide polymorphisms (SNPs) in 3'UTR of key DNA repair enzyme genes are associated with inter-individual differences of DNA repair capacity (DRC) and susceptibility to a variety of human malignancies such as lung cancer. In this study, seven candidate SNPs in 3'UTR of DRC-related genes including ERCC1 (rs3212986, rs2336219, and rs735482), OGG1 (rs1052133), MLH3 (rs108621), CD3EAP (rs1007616), and PPP1R13L (rs6966) were analyzed in 300 lung cancer patients and controls from the northeast of China. Furthermore, we introduced ERCC1 (CDS+3'UTR) or CD3EAP (CDS) cDNA clone to transfect HEK293T and 16HBE cells. Cell viability between different genotypes of transfected cells exposed to BPDE was detected by CCK-8 assay, while DNA damage was visualized using γH2AX immunofluorescence and the modified comet assay. We found that minor A-allele of rs3212986 could reflect a linkage with increasing risk of NSCLC. Compared with CC genotype, AA genotype of ERCC1 rs3212986 was a high-risk factor for NSCLC (OR = 3.246; 95%CI: 1.375-7.663). Particularly stratified by smoking status in cases and controls, A allele of ERCC1 rs3212986 also exhibited an enhanced risk to develop lung cancer in smokers only (P < 0.05). Interestingly, reduced repair efficiency of DNA damage was observed in 293T ERCC1(AA) and 16HBE ERCC1(AA), while no significant difference was appeared in two genotypes of CD3EAP (3' adjacent gene of ERCC1) overexpressed cells. Our findings suggest that rs3212986 polymorphism in 3'UTR of ERCC1 overlapped with CD3EAP may affect the repair of the damage induced by BPDE mainly via regulating ERCC1 expression and become a potential biomarker to predict smoking-related lung cancer.