Triple negative breast cancer: microRNA expression profile and novel discriminators according to BRCA1 status

Identification of CSNK1D and KLK6 as two common upregulated genes present in BRCA1 mutated triple-negative breast cancer and ovarian epithelial carcinoma

Deficiency in the breast cancer type 1 (BRCA1) gene expression predisposes to triple-negative breast cancer (TNBC) and ovarian cancer (OC). We previously identified by Comparative Genomic Hybridization (CGH) array a gain in the 17q25.3 genomic region in 90% of the BRCA1 mutated TNBC tissues, where 17 genes were up-regulated. A second region (Chr19_45681759_54221324) was identified as the second most frequent gain in the BRCA1-mutated population and has not yet been described in the context of BRCA1 mutation. We thus aimed to validate the expression of the Casein kinase 1 delta (CSNK1D) gene of Chr17 in TNBC and OC cell lines and to investigate the expression of genes of Chr19 in TNBC cell lines and tissues as well as in OC cell lines. Expression level of the genes of the 17q25.3, 19q13.32,13.33 and 13.41 chromosomal regions was analyzed using RT-PCR in BRCA1 deficient TNBC and OC cell lines, as well as in 10 BRCA1-mutated TNBC tissues versus 10 wild type carriers. Our results revealed a significant upregulation of CSNK1D gene expression in BRCA1 deficient TNBC and OC cell lines when compared to control ones, and a significant aberration in the expression of the other six genes of Chr19 was observed. Interestingly, upregulation of kallikrein-related peptidase 6 (KLK6) was detected among the BRCA1 deficient TNBC (cell lines and tissues) and OC cell lines. In conclusion, our results suggested that CSNK1D and KLK6 expression levels could be very promising in the search for biomarkers for BRCA1 deficient TNBC and OC.

Unveiling Role of MicroRNAs in Metastasizing Triple Negative Breast Cancer: From Therapeutics to Delivery

Triple negative breast cancers are malignant, heterogeneous tumors with high histological grades, increased reoccurrence, and cancer-related death rates. TNBC metastasis to the brain, lungs, liver, and lymph nodes is a complex process regulated by epithelial to mesenchymal transition, intravasation, extravasation, stem cell niche, and migration. Aberrant expression of miRNAs, also known as a transcriptional regulators of genes, may function as oncogenes or tumor suppressors. In this review, we systematically elucidated the biogenesis and tumor suppressor role of miRNA in targeting distant metastasis of TNBC cells and the above-mentioned underlying mechanisms involved in complicating the disease. Apart from their therapeutic implications, the emerging roles of miRNAs as prognostic markers have also been discussed. To overcome delivery bottlenecks, RNA nanoparticles, nano-diamonds, exosomes, and mesoporous silica nanoparticle-mediated delivery of miRNAs have been contemplated. Altogether, the present review article uncovers the potential role of miRNA in antagonizing distant metastasis of TNBC cells, and highlights their clinical significance as prognostic markers and possible drug delivery strategies to enhance the likely outcome of miRNA-based therapy against the disease.

Polymorphisms in lncRNA MIR2052HG and susceptibility to breast cancer in Chinese population

Background: Published studies based on pharmacokinetics have explored the relationship between the lncRNA MIR2052HG and the prognosis of breast cancer (BC) resistance and recurrence. However, the underlying association of MIR2052HG SNPs with BC development remains unclear.

Methods: Combining bioinformatics and databases, SNPs (Single Nucleotide Polymorphisms) in the MIR2052HG gene were screened, and SNPs in the lncRNA MIR2052HG were selected for genotyping among 504 Chinese Han patients and 505 healthy controls, which were frequency-matched for age (±2 years). Logistic regression analysis was used to explore the association between MIR2052HG SNPs and the BC risk. Interactions between the MIR2052HG SNPs and reproductive factors were further evaluated using the multifactor dimensionality reduction (MDR) method. qRT–PCR was performed to detect MIR2052HG expression in individuals with different genotypes of rs34841297. The target miRNA, miR-4456 of MIR2052HG rs34841297 was predicted by websites and confirmed by performing dual luciferase gene reporter assays. CCK-8 and Transwell experiments were designed to explore the effects of miR-4456 on the proliferation, invasion and migration of BC cells.

Results: In this study, nine SNPs were screened. After adjusting for age, menarche age, menopausal status, number of pregnancies, history of abortions, breast feeding history and family history of BC, the results of the logistic regression analysis showed the rs34841297 A/- gene polymorphism was positively correlated with the incidence of BC. Compared with the AA genotype, patients with the A-+-- genotype of rs34841297 at age<50 years, and menarche age<14 years, Premenopausal status, history of abortion, no history of breastfeeding and no family history of tumors in first-degree relatives had an increased risk of BC. MDR results revealed that individuals with rs34841297 - (homozygous deletion) of the A allele who were not menopausal and had no history of breastfeeding had a higher risk of BC. qRT–PCR results revealed that homozygous deletion (1.68±1.37) of the rs34841297 A- genotype resulted in higher MIR2052HG expression than the heterozygous deletion genotype (0.95±0.94) and wild AA genotype (0.26±0.12). Binding between MIR2052HG and miR-4456 was occurred when rs34841297 carried the AA genotype. Moreover, preliminary functional studies indicated that the overexpression of miR-4456 increased the proliferation, invasion and migration of BC cells.

Conclusion: Our study showed that the MIR2052HG gene polymorphism may be related to BC susceptibility, and the MIR2052HG rs34841297 A/- genotype may probably affect the proliferation, invasion and migration of BC cells by modulating the interactions with of miR-4456.