“Oncogenic Shock”: Turning an Activated Kinase against the Tumor Cell
ABSTRACT Accumulating evidence indicates that mutationally activated kinases are especially good targets for anti-cancer drugs. It has been suggested that this reflects a state of "oncogene addiction" of tumor cells. We recently reported experimental studies that may provide a molecular mechanism to explain such apparent dependency. We find that oncogenic kinases produce both pro-survival and pro-apoptotic signals that decay at different rates upon oncogene inactivation. Pro-survival signals are rapidly attenuated, whereas pro-apoptotic signals are relatively longer-lived. This differential signal decay creates a temporal window during which pro-apoptotic outputs from the oncogenic kinase predominate to actively promote tumor cell death upon kinase inhibition. We refer to this mechanism as "oncogenic shock", and suggest that it has significant implications for the optimal therapeutic use of targeted kinase inhibitors.
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ABSTRACT: Lung cancer is a heterogeneous and complex disease. Genomic and transcriptomic profiling of lung cancer not only further our knowledge about cancer initiation and progression, but could also provide guidance on treatment decisions. The fact that targeted treatment is most successful in a subset of tumors indicates the need for better classification of clinically related molecular tumor phenotypes based on better understanding of the mutations in relevant genes, especially in those oncogenic driver mutations. EGFR gene mutations, KRAS gene mutations, EML4-ALK rearrangements and altered MET signaling are widely recognized alterations that play important roles in both the biological mechanisms and the clinical sensitivity to treatment in lung cancer. In this article, we reviewed the discovery of the clinical values of these oncogenic driver mutations and the clinical studies revealing the prognostic and predictive values of these biomarkers for clinical sensitivity and resistance to anti-EGFR therapy or other targeted therapies. These form the basis of personalized treatment in lung cancer based on biomarker profiles of individual tumor, leading to therapeutic advancement and betterment.01/2013; 1(1). DOI:10.1186/2213-0802-1-6
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ABSTRACT: In pugilistic parlance, the one-two punch is a devastating combination of blows, with the first punch setting the stage and the second delivering the knock-out. This analogy can be extended to molecularly targeted cancer therapies, with oncogene addiction serving to set the stage for tumor cell killing by a targeted therapeutic agent. While in vitro and in vivo examples abound documenting the existence of this phenomenon, the mechanistic underpinnings that govern oncogene addiction are just beginning to emerge. Our current inability to fully exploit this weakness of cancer cells stems from an incomplete understanding of oncogene addiction, which nonetheless represents one of the rare chinks in the formidable armor of cancer cells.Genes & Development 01/2008; 21(24):3214-31. DOI:10.1101/gad.1609907 · 12.64 Impact Factor
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ABSTRACT: Dasatinib is an oral small molecule inhibitor of Abl and Src family tyrosine kinases (SFK), including p56(Lck) (Lck). Given the central importance of Lck in transmitting signals from the T-cell receptor (TCR) signaling complex and the potent ability of dasatinib to inhibit Lck activity, we hypothesized this agent could provide a novel route of immunomodulation via targeted inhibition of antigen-induced signaling. Herein, we show that dasatinib inhibits TCR-mediated signal transduction, cellular proliferation, cytokine production, and in vivo T-cell responses. However, dasatinib-mediated inhibition does not induce apoptosis because the effect is reversible or may be overcome by signals bypassing the TCR, such as phorbol ester. Signal transduction and proliferative responses via IL-2 remain essentially unperturbed, suggesting that dasatinib displays specificity for TCR signaling. In addition, dasatinib combined with cyclosporine A or rapamycin led to a much more potent inhibition of T-cell activation, suggesting that targeted inhibition of Lck could be a useful adjunct for enhanced immunomodulation. In combination with currently available immunomodulatory agents, SFK inhibition could potentially increase immunomodulatory efficacy while minimizing toxicity of individual agents.Blood 03/2008; 111(3):1366-77. DOI:10.1182/blood-2007-04-084814 · 10.43 Impact Factor