IntroductionKRAS oncogene mutations (MUTKRAS) drive resistance to EGFR inhibition by providing alternative signaling as demonstrated in colo-rectal cancer. In non-small cell lung cancer (NSCLC), the efficacy of treatment with EGFR tyrosine kinase inhibitors (EGFR-TKIs) depends on activating EGFR mutations (MUTEGFR). However, inhibition of EGFR may select resistant cells displaying alternative signaling, i.e., KRAS, or restoration of EGFR activity due to additional MUTEGFR, i.e., the c.2369C > T (p.T790MEGFR).AimThe aim of this study was to investigate the appearance of MUTKRAS during EGFR-TKI treatment and their contribution to drug resistance.MethodsThis study used cell-free circulating tumor DNA (cftDNA) to evaluate the appearance of codon 12 MUTKRAS and p.T790MEGFR mutations in 33 advanced NSCLC patients progressing after an EGFR-TKI.Resultsp.T790MEGFR was detected in 11 (33.3%) patients, MUTKRAS at codon 12 in 3 (9.1%) while both p.T790MEGFR and MUTKRAS codon 12 were found in 13 (39.4%) patients. Six patients (18.2%) were KRAS wild-type (WTKRAS) and negative for p.T790MEGFR. In 8 subjects paired tumor re-biopsy/plasma samples were available; the percent concordance of tissue/plasma was 62.5% for p.T790MEGFR and 37.5% for MUTKRAS. The analysis of time to progression (TTP) and overall survival (OS) in WTKRAS vs. MUTKRAS were not statistically different, even if there was a better survival with WTKRAS vs. MUTKRAS, i.e., TTP 14.4 vs. 11.4 months (p = 0.97) and OS 40.2 vs. 35.0 months (p = 0.56), respectively.ConclusionsMUTKRAS could be an additional mechanism of escape from EGFR-TKI inhibition and cftDNA is a feasible approach to monitor the molecular development of drug resistance.
Dystroglycan (DG) is an adhesion molecule formed by two subunits, α (extracellular) and β (transmembrane) DG, which are codified by a single gene and form a continuous link from the extracellular matrix to the intracellular cytoskeleton. Reduction or loss of expression of DG has been observed in human cancer cell lines and primary tumors and has been suggested to promote tumor development and invasiveness.In this study, the human breast epithelial non-tumorigenic MCF10F and the breast cancer MCF7 cell lines were engineered to stably express an exogenous DG cDNA and the effects on the phenotype of both cell lines were evaluated. The MCF10F transfected cells displayed an increased expression of both DG subunits which was associated with inhibition of the anchorage-dependent growth, accumulation of cells in the G 0 /G 1 phase of the cell cycle and increased adhesion to a substratum. The MCF7 transfected cells were unable to restore α-DG despite an increased expression of the β-DG subunit. Anchoragedependent and independent growth and the in vivo tumorigenicity were reduced in these derivatives that also displayed a reduced adhesion to a substratum and were shown to release α-DG in the culture medium.These findings confirm and extend previous evidence that transformation of mammary epithelial cells is associated with loss of their ability to retain α-DG on the cell membrane. Moreover, they indicate that DG is involved in cell functions other than cell adhesion to the extracellular matrix, and that its loss of function might predispose to tumor progression by compromising regulatory controls over cell growth and proliferation.
The epidermal growth factor (EGF) plays a role in the development of prostate cancer, which becomes essential after androgen resistance has emerged. The EGF receptor (EGFR) is therefore a potential target for anticancer therapy. We evaluated the effects of ZD1839 ('Iressa'), an orally active EGFR-tyrosine kinase inhibitor, on prostate cancer cell lines. The effects of ZD1839 were evaluated on the anchorage dependent and independent growth of androgen-responsive (LNCaP) and androgen-independent (DU145 and PC3) cells by a cell proliferation assay, cell counting, and soft agar analysis. Flow cytometric analysis and Western blotting were used to assess the effects on the cell-cycle and on protein expression levels, respectively. ZD1839 caused a dose- and time-dependent growth inhibition in all three cell lines. A dose-dependent supra-additive increase in growth inhibition was observed when ZD1839 was combined with the antiandrogen flutamide or ionizing radiation (IR). The antiproliferative effect of ZD1839 was mainly cytostatic and associated with a block in the G(0)/G(1) phase of the cell-cycle, evident after about 12 h of treatment. In the DU145 cells this block was associated with an increase in expression of the CDK inhibitor p27(Kip1), both in the cytoplasmic and nuclear fractions. The increase in p27(Kip1) was not evident in the LNCaP and PC3 cells. No changes were observed in the expression of cyclin D1 protein. These results demonstrate the antiproliferative effects of ZD1839 on the growth of prostate cancer cells and suggest that inhibition of EGFR-associated signal transduction pathway might represent a promising novel therapeutic strategy for the treatment of prostate cancer.
Our nomogram may be a useful tool to predict the probability of death within 12 weeks in patients with refractory mCRC. Based on four easy-to-collect variables, the 'Colon Life' nomogram and free app for smartphones may improve mCRC patients' selection for later-line therapies and assist researchers for the enrollment in clinical trials in this setting.
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