Comprehensive profiling of BRCA1 and BRCA2 variants in breast and ovarian cancer in Chinese patients.

The identification and interpretation of germline BRCA1/2 variants become increasingly important in breast and ovarian cancer (OC) treatment. However, there is no comprehensive analysis of the germline BRCA1/2 variants in a Chinese population. Here we performed a systematic review and meta-analysis on such variants from 94 publications. A total of 2,128 BRCA1/2 variant records were extracted, including 601 from BRCA1 and 632 from BRCA2. In addition, 414, 734, 449, and 307 variants were also recorded in the BIC, ClinVar, ENIGMA, and UMD databases, respectively, and 579 variants were newly reported. Subsequent analysis showed that the overall germline BRCA1/2 pathogenic variant frequency was 5.7% and 21.8% in Chinese breast and OC, respectively. Populations with high-risk factors exhibited a higher pathogenic variant percentage. Furthermore, the variant profile in Chinese is distinct from that in other ethnic groups with no distinct founder pathogenic variants. We also tested our in-house American College of Medical Genetics-guided pathogenicity interpretation procedure for Chinese BRCA1/2 variants. Our results achieved a consistency of 91.2-97.6% (5-grade classification) or 98.4-100% (2-grade classification) with public databases. In conclusion, this study represents the first comprehensive meta-analysis of Chinese BRCA1/2 variants and validates our in-house pathogenicity interpretation procedure, thereby providing guidance for further PARP inhibitor development and companion diagnostics in the Chinese population.

d-/l-Isothymidine incorporation in the core sequence of aptamer BC15 enhanced its binding affinity to the hnRNP A1 protein.

The heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) was reported to participate in the development of a variety of tumors. BC15 is a DNA aptamer targeting hnRNP A1. Firstly, through sequence truncation, we identified 31-mer sequence BC15-31 as the core sequence of BC15 with a strong binding affinity and high selectivity to the hnRNP A1 protein. Isothymidine (isoT) modification was then applied for the structural optimization of BC15-31, systematic modification and biological evaluation were carried out. Incorporation of isoT in the 1,3 sites at the 5'-end of BC15-31 can significantly enhance the protein affinity. Chemical modifications close to the 3'-end can greatly improve the stability of the aptamer. Furthermore, BC15-31 modified with isoT at both the 5'-end and 3'-end displayed an additive effect with enhanced bioactivity and stability at the same time. Our study strategy on BC15 provides a useful guideline for chemical modification and optimization of the aptamer for further clinical application.

[Treatment of triple negative breast cancer cells with combination of mTOR1/2 inhibitor AZD8055 and MEK1/2 inhibitor PD0325901].

MEK inhibition activates PI3K/AKT/mTOR pathway in triple negative breast cancer (TNBC) cell lines. Combination of PI3K inhibitor and MEK1/2 inhibitor is not appropriate for PI3K inhibitor insensitive TNBC cell lines. This study was designed to investigate the effects of dual treatments with mTOR1/2 inhibitor AZD8055 and MEK1/2 inhibitor PD0325901 in MDA-MB-435 cell line. MEK1/2 inhibition led to activation of AKT, which is the downstream signaling protein of PI3K pathway. The combination inhibited the phosphorylation of AKT and therefore abolished the feedback interaction of two pathways. Cell proliferation assay and DNA replication assay demonstrated that the dual treatments led to a significant synergistic inhibition of cell cycle progression and cell proliferation.

Anticancer effects of combinational treatment with BRAFV600E siRNA and PI3K pathway inhibitors in melanoma cell lines harboring BRAFV600E.

In the present study, the anti-tumor effects of combination treatment with an siRNA targeting B-Raf proto-oncogene serine/threonine kinase (BRAF)V600E and phosphoinositide 3-kinase (PI3K) signaling pathway inhibitors was investigated in melanoma cell lines harboring BRAFV600E. Human melanoma A375 and WM115 cells were treated with siRNA targeting to BRAF or BRAFV600E, combined with treatment with PI3K signaling pathway inhibitors. CCK-8 and EdU proliferation assays were performed to assess cell viability and proliferation, respectively, following treatment. In addition, flow cytometry analysis was performed to determine cell cycle distribution, and western blot analysis was performed to analyze the activity of the extracellular signal-regulated kinase (ERK) and PI3Ksignaling pathways following treatment. Targeting BRAFV600E using small interfering (si)RNA significantly decreased cell viability and DNA replication in tumor cell lines that harbor oncogenic BRAFV600E. Inhibition of BRAFV600E by siRNA combined with treatment with PI3K or mammalian target of rapamycin signaling pathway inhibitors significantly decreased cell viability and proliferation compared with siRNA or inhibitor treatment alone. Concomitant BRAFV600E and PI3K inhibition led to G1/S phase arrest in melanoma cells. However, melanoma cells in which oncogenic BRAFV600E is not highly expressed (WM115 cells) were not sensitive to BRAFV600E targeted therapy. The PI3K signaling pathway inhibitors were more effective in this cell line. The results from the present study provide an insight into the potential effectiveness of combination therapy and personalized cancer treatments.