Detection of melanogenesis- and anti-apoptosis-associated melanoma factors: Array CGH and PPI mapping integrating study

Background: We investigated melanogenesis- and anti-apoptosis-related melanoma factors in melanoma cells (TXM1, TXM18, A375P, and A375SM). Objective: To find melanoma associated hub factor, high-throughput screening-based techniques integrating with bioinformatics were investigated. Methods: Array CGH analysis was conducted with a commercial system. Total genomic DNAs prepared individually from each cell line with control DNA were properly labeled with Cy3-dCTP and Cy5-dCTP and hybridizations and subsequently performed data treatment by the log2 green (G; test) to red (R; reference) fluorescence ratios (G/R). Gain or loss of copy number was judged by spots with log2-transformed ratios. PPI mapping analysis of detected candidate genes based on the array CGH results was conducted using the human interactome in the STRING database. Energy minimization and a short molecular dynamics (MD) simulation using the implicit solvation model in CHARMM were performed to analyze the interacting residues between YWHAZ and YWHAB. Results: Three genes (BMP-4, BFGF, LEF-1) known to be involved in melanogenesis were found to lose chromosomal copy numbers, and Chr. 6q23.3 was lost in all tested cell lines. Ten hub genes (CTNNB1, PEX13, PEX14, PEX5, IFNG, EXOSC3, EXOSC1, EXOSC8, UBC, and PEX10) were predicted to be functional interaction factors in the network of the 6q23.3 locus. The apoptosis-associated genes E2F1, p50, BCL2L1, and BIRC7 gained, and FGF2 lost chromosomal copy numbers in the tested melanoma cell lines. YWHAB, which gained chromosomal copy numbers, was predicted to be the most important hub protein in melanoma cells. Molecular dynamics simulations for binding YWHAB and YWHAZ were conducted, and the complex was predicted to be energetically and structurally stable through its 3 hydrogen-bond patterns. The number of interacting residues is 27. Conclusion: Our study compares genome-wide screening interactomics predictions for melanoma factors and offers new information for understanding melanogenesis- and anti-apoptosis-associated mechanisms in melanoma. Especially, YWHAB was newly detected as a core factor in melanoma cells.

Chromosomal copy number heterogeneity predicts survival rates across cancers

Survival rates of cancer patients vary widely within and between malignancies. While genetic aberrations are at the root of all cancers, individual genomic features cannot explain these distinct disease outcomes. In contrast, intra-tumour heterogeneity (ITH) has the potential to elucidate pan-cancer survival rates and the biology that drives cancer prognosis. Unfortunately, a comprehensive and effective framework to measure ITH across cancers is missing. Here, we introduce a scalable measure of chromosomal copy number heterogeneity (CNH) that predicts patient survival across cancers. We show that the level of ITH can be derived from a single-sample copy number profile. Using gene-expression data and live cell imaging we demonstrate that ongoing chromosomal instability underlies the observed heterogeneity. Analysing 11,534 primary cancer samples from 37 different malignancies, we find that copy number heterogeneity can be accurately deduced and predicts cancer survival across tissues of origin and stages of disease. Our results provide a unifying molecular explanation for the different survival rates observed between cancer types.

A Retrospective Study of Noninvasive Prenatal Testing for Chromosome Aneuploidies and Sub-Chromosomal Copy Number Variations in 24359 Single Pregnancies

Background: With the development of whole-genome sequencing, small sub-chromosomal deletions and duplications could be found by non-invasive prenatal testing(NIPT). This study aimed to review the efficiency of NIPT as a screening test for aneuploidies and sub-chromosomal copy number variations (CNVs) in 24359 single pregnancies.Methods: A total of 24359 single pregnancies with different clinical indications were retrospectively analyzed. The positive predictive value （PPV）of chromosome aneuploidies and subchromosomal CNVs were analyzed. Pathogenicity of abnormal NIPT results were assessed according to American College of Medical Genetics and Genomics(ACMG). Results: A total of 442 pregnancies (442/24359,1.9%) were with abnormal NIPT results. PPV for trisomy 21(T21), trisomy 18 (T18), trisomy 13 (T13), and sex chromosome aneuploidies (SCAs) was 84.8%, 54.2%, 11.1% an 40.5% respectively. The PPV for sub-chromosomal CNVs was 59.0% (46/78). The PPV for CNVs ≤5 Mb was 68.9% (31/45), for CNVs within 5-10 Mb was 83.3%(5/6) and for CNVs ≥10 Mb was 37.1% (10/27) respectively. The clinical information, prenatal diagnosis results and follow-up results of 46 true positive cases, 6 cases with sub-chromosomal CNVs inconsistent with NIPT and 1 false negative case were also described in detail.Conclusions: Our data have potential significance in demonstrating the significance of NIPT not only for common whole chromosome aneuploidies but also for sub-chromosomal CNVs. Besides, the clinical information, prenatal diagnosis results and follow-up results of 52 cases with sub-chromosomal CNVs and 1 false negative case would provide important guidance for genetic counseling.