PIK3CA mutations enable targeting of a breast tumor dependency through mTOR-mediated MCL-1 translation.

Therapies that efficiently induce apoptosis are likely to be required for durable clinical responses in patients with solid tumors. Using a pharmacological screening approach, we discovered that combined inhibition of B cell lymphoma-extra large (BCL-XL) and the mammalian target of rapamycin (mTOR)/4E-BP axis results in selective and synergistic induction of apoptosis in cellular and animal models of PIK3CA mutant breast cancers, including triple-negative tumors. Mechanistically, inhibition of mTOR/4E-BP suppresses myeloid cell leukemia-1 (MCL-1) protein translation only in PIK3CA mutant tumors, creating a synthetic dependence on BCL-XL This dual dependence on BCL-XL and MCL-1, but not on BCL-2, appears to be a fundamental property of diverse breast cancer cell lines, xenografts, and patient-derived tumors that is independent of the molecular subtype or PIK3CA mutational status. Furthermore, this dependence distinguishes breast cancers from normal breast epithelial cells, which are neither primed for apoptosis nor dependent on BCL-XL/MCL-1, suggesting a potential therapeutic window. By tilting the balance of pro- to antiapoptotic signals in the mitochondria, dual inhibition of MCL-1 and BCL-XL also sensitizes breast cancer cells to standard-of-care cytotoxic and targeted chemotherapies. Together, these results suggest that patients with PIK3CA mutant breast cancers may benefit from combined treatment with inhibitors of BCL-XL and the mTOR/4E-BP axis, whereas alternative methods of inhibiting MCL-1 and BCL-XL may be effective in tumors lacking PIK3CA mutations.

Management of epidermal growth factor receptor inhibitor-associated rash: a systematic review.

Cancer patients treated with epidermal growth factor receptor inhibitors (EGFRIs) frequently experience skin toxicities (rash) that can compromise their quality of life and lead to dose reduction or discontinuation of treatment. Reflecting the need for effective management of EGFRI-associated rash, a number of clinical practice guidelines and management recommendations have been developed. The objective of this systematic review is to identify and summarize all available published recommendations of rash management strategies and evaluate their basis of evidence, to describe consensus in the recommendations, and where there is a lack of consensus to describe the opportunities for future clinical research to improve clinical practice in the management of EGFRI rash. Fifty-nine articles published from 2005-2011 were selected for inclusion in the systematic review. Common drug recommendations were oral and topical antibiotics, topical corticosteroids, and antihistamines; low-grade rash was generally recommended to be managed with topical antibiotics or corticosteroids, grade 2 rash with oral antibiotics or antihistamines, and severe grades of rash with oral corticosteroids or delay/dose reduction of EGFRI. The focus of clinical practice guidelines and recommendations was on reactive management. A better understanding of pre-emptive versus reactive treatment with the implementation of appropriately designed randomized controlled studies could support a more effective management of EGFRI-associated rash and improve patient outcomes. Consideration of patients' self-reported outcomes and consistent grading of rash toxicity are also recommended. Funding/sponsor: Eli Lilly & Co, Bristol-Myers Squibb.

Male biased gene flow in banana pseudostem weevil (Odoiporus longicollis Oliver) as revealed by analysis of the COI-tRNA(Leu) COII region.

The genetic diversity amongst thirty weevils representing six Indian populations of banana pseudostem weevil, i.e., Odoiporus longicollis (Oliver) was estimated by sequence analysis of the partial COI-tRNA(Leu)-COII region. The sequences exhibited AT bias typical of insect mitochondrial DNA which was highest in the first codon position of COI and in the third codon position of COII. There was no phylogeographic distribution of the populations. The Fu and Li's D and F tests were non-significant for this mitochondrial region. No Wolbachia infection was detected in any of the populations. The genetic differentiation amongst the populations was highly significant (p < 0.001; χ2 = 123.333; df = 75), suggesting restricted gene flow between the populations. This result did not correlate with that obtained with nuclear rDNA markers, i.e., ITS1 and ITS2, suggesting a male biased gene flow between the populations.

Missense and silent mutations in COL2A1 result in Stickler syndrome but via different molecular mechanisms.

Stickler syndrome due to mutations in COL2A1 is usually the result of premature termination codons and nonsense mediated decay resulting in haploinsufficiency of type II collagen. Here we present two missense mutations and one apparently silent mutation that each result in Stickler syndrome, but via different molecular mechanisms. One alters the translation initiating ATG codon. The second mutation is a unique glycine substitution in the minor collagen helix of the procollagen. To our knowledge a glycine substitution has not previously been reported in this region of fibrillar procollagens. The third mutation appears to be a silent change altering a GGC codon to GGT both for glycine, but use of a splicing reporter assay demonstrates that it results in missplicing and a shift in the reading frame.