Genomic and epigenomic BRCA alterations predict adaptive resistance and response to platinum-based therapy in patients with triple-negative breast and ovarian carcinomas.

Triple-negative breast cancer (TNBC) and ovarian carcinomas (OvCas) with BRCA1 promoter methylation (BRCA1meth) respond more poorly to alkylating agents compared to those bearing mutations in BRCA1 and BRCA2 (BRCAmut). This is a conundrum given the biologically equivalent homologous recombination deficiency (HRD) induced by these genetic and epigenetic BRCA perturbations. We dissected this problem through detailed genomic analyses of TNBC and OvCa cohorts and experimentation with patient-derived xenografts and genetically engineered cell lines. We found that despite identical downstream genomic mutational signatures associated with BRCA1meth and BRCAmut states, BRCA1meth uniformly associates with poor outcomes. Exposure of BRCA1meth TNBCs to platinum chemotherapy, either as clinical treatment of a patient or as experimental in vivo exposure of preclinical patient derived xenografts, resulted in allelic loss of BRCA1 methylation and increased BRCA1 expression and platinum resistance. These data suggest that, unlike BRCAmut cancers, where BRCA loss is a genetically "fixed" deficiency state, BRCA1meth cancers are highly adaptive to genotoxin exposure and, through reversal of promoter methylation, recover BRCA1 expression and become resistant to therapy. We further found a specific augmented immune transcriptional signal associated with enhanced response to platinum chemotherapy but only in patients with BRCA-proficient cancers. We showed how integrating both this cancer immune signature and the presence of BRCA mutations results in more accurate predictions of patient response when compared to either HRD status or BRCA status alone. This underscores the importance of defining BRCA heterogeneity in optimizing the predictive precision of assigning response probabilities in TNBC and OvCa.

A novel anti-melanoma SRC-family kinase inhibitor.

The major drawback of melanoma therapy with BRAF and MAPK inhibitors is the innate and acquired drug resistance. We therefore explored alternative targets and developed a new compound, SAB298, that is a SRC-family kinase (SFK) inhibitor. The drug is cytotoxic to patient-derived melanoma cells regardless of oncogene expression and inhibits tumor growth in vivo. As expected, it inhibited SRC and PI3K activity, and had the additional property of ERBB2 inhibition, that lead to inactivation of the two ERK phosphatases PP2A and SHP2. In 57% of the melanoma cell lines tested, the consequent increase in ERK activity lead to proteolytic degradation of its substrate, the lineage specific transcription factor MITF, likely contributing to growth arrest. Treatment with a combination of SAB298 and AZD6244 (selumetinib), induced a synergistic growth inhibition, suggesting that the new compound could be used in the clinic as a substitute for, or in combination with MAPK inhibitors.

GNA14 Somatic Mutation Causes Congenital and Sporadic Vascular Tumors by MAPK Activation.

Vascular tumors are among the most common neoplasms in infants and children; 5%-10% of newborns present with or develop lesions within the first 3 months of life. Most are benign infantile hemangiomas that typically regress by 5 years of age; other vascular tumors include congenital tufted angiomas (TAs), kaposiform hemangioendotheliomas (KHEs), and childhood lobular capillary hemangiomas (LCHs). Some of these lesions can become locally invasive and unresponsive to pharmacologic intervention, leading to significant complications. Recent investigation has revealed that activating mutations in HRAS, KRAS, NRAS, GNAQ, and GNA11 can cause certain types of rare childhood vascular tumors, and we have now identified causal recurrent somatic activating mutations in GNA14 by whole-exome and targeted sequencing. We found somatic activating GNA14 c.614A>T (p.Gln205Leu) mutations in one KHE, one TA, and one LCH and a GNA11 c.547C>T (p.Arg183Cys) mutation in two LCH lesions. We examined mutation pathobiology via expression of mutant GNA14 or GNA11 in primary human endothelial cells and melanocytes. GNA14 and GNA11 mutations induced changes in cellular morphology and rendered cells growth-factor independent by upregulating the MAPK pathway. Our findings identify GNA14 mutations as a cause of childhood vascular tumors, offer insight into mechanisms of oncogenic transformation by mutations affecting Gaq family members, and identify potential targets for therapeutic intervention.

Exome sequencing identifies recurrent mutations in NF1 and RASopathy genes in sun-exposed melanomas.

We report on whole-exome sequencing (WES) of 213 melanomas. Our analysis established NF1, encoding a negative regulator of RAS, as the third most frequently mutated gene in melanoma, after BRAF and NRAS. Inactivating NF1 mutations were present in 46% of melanomas expressing wild-type BRAF and RAS, occurred in older patients and showed a distinct pattern of co-mutation with other RASopathy genes, particularly RASA2. Functional studies showed that NF1 suppression led to increased RAS activation in most, but not all, melanoma cases. In addition, loss of NF1 did not predict sensitivity to MEK or ERK inhibitors. The rebound pathway, as seen by the induction of phosphorylated MEK, occurred in cells both sensitive and resistant to the studied drugs. We conclude that NF1 is a key tumor suppressor lost in melanomas, and that concurrent RASopathy gene mutations may enhance its role in melanomagenesis.

Comparison of laser-assisted hatching and acidified Tyrode's hatching by evaluation of blastocyst development rates in sibling embryos: a prospective randomized trial.

OBJECTIVE: To assess two zona drilling methods in terms of blastocyst development rates using sister embryos. DESIGN: Prospective, randomized study. Sister embryos of 14 patients were randomly assigned on day 3 to acidified Tyrode's zona drilling or to laser zona drilling. After biopsy, subsequent embryo culture until the blastocyst stage (day 5) was performed. SETTING: Private fertility center. PATIENT(S): Patients undergoing IVF-preimplantation genetic diagnosis. INTERVENTION(S): Embryo biopsy using either laser-assisted hatching or acidified Tyrode's hatching on sibling embryos and subsequent blastocyst development evaluation. MAIN OUTCOME MEASURE(S): Evaluation of blastocyst development in terms of degree of expansion and cell number in the inner cell mass and trophectoderm. RESULT(S): Blastocyst development rates (and blastocyst quality) were similarly high in both the acidified Tyrode's hatching group and the laser-assisted hatching group. CONCLUSION(S): Laser hatching does not impair embryonic development to the blastocyst stage, demonstrating that laser-assisted hatching is a suitable alternative to the use of acidified Tyrode's solution for zona drilling.