T790M may not be a rare event before or after TKI therapy in patients with NSCLC with EGFR-activating mutations. The pretreatment T790M mutation was associated with shorter PFS with EGFR TKI therapy in patients with NSCLC.

Tumor-associated macrophages (TAMs) and cyclooxygenase-2 (COX-2) are associated with invasion, angiogenesis, and poor prognosis in many human cancers. However, the role of TAMs in human basal cell carcinoma (BCC) remains elusive. We found that the number of TAMs infiltrating the tumor is correlated with the depth of invasion, microvessel density, and COX-2 expression in human BCC cells. TAMs also aggregate near COX-2 expressing BCC tumor nests. We hypothesize that TAMs might activate COX-2 in BCC cells and subsequently increase their invasion and angiogenesis. TAMs are a kind of M2 macrophage derived from macrophages exposed to Th2 cytokines. M2-polarized macrophages derived from peripheral blood monocytes were cocultured with BCC cells without direct contact. Coculture with the M2 macrophages induced COX-2-dependent invasion and angiogenesis of BCC cells. Human THP-1 cell line cells, after treated with phorbol myristate acetate (PMA), differentiated to macrophages with M2 functional profiles. Coculture with PMA-treated THP-1 macrophages induced COX-2-dependent release of matrix metalloproteinase-9 and subsequent increased invasion of BCC cells. Macrophages also induced COX-2-dependent secretion of basic fibroblast growth factor and vascular endothelial growth factor-A, and increased angiogenesis in BCC cells.

This study is to investigate the molecular mechanism of radiation-enhanced cell invasiveness of hepatocellular carcinoma (HCC) correlating with clinical patients undergoing radiotherapy and subsequently developing metastasis. Three HCC cell lines (HepG2, Hep3B and Huh7) and normal hepatocyte cell line (CL-48) were irradiated with different doses. The effect of radiation on cell invasiveness was determined using the Boyden chamber assay. Radiation-enhanced invasion capability was evident in HCC cells but not in normal hepatocytes. Invasion was observed in gelatin-coated but not fibronectin-coated or type I collagen-coated membranes. Radiation upregulated matrix metalloproteinase-9 (MMP-9) mRNA level, MMP-9 protein level and MMP-9 activity. MMP-9 antisense oligonucleotides inhibited radiation-induced MMP-9 expression and thereby significantly inhibited radiationinduced HCC invasion. Furthermore, phosphatidylinositol 3-kinase (PI3K)/Akt chemical inhibitors LY294002 and wortmannin suppressed radiation-induced MMP-9 mRNA expression. Transient transfection with dominantnegative Akt plasmid also showed that the PI3K/Aktsignaling pathway was involved in this radiation-induced MMP-9 expression. Moreover, nuclear factor-jB (NFjB) decoy oligodeoxynucleotide suppressed radiation enhanced MMP-9 promoter activity completely. PI3K/ Akt chemical inhibitors inhibited radiation-induced NFjB-driven luciferase promoter activity. Taken together, our results indicated that sublethal dose of radiation could enhance HCC cell invasiveness by MMP-9 expression through the PI3K/Akt/NF-jB signal transduction pathway.

Reports of the bone-protective effects of resveratrol, a naturally occurring phytoestrogen and agonist for the longevity gene SIRT1, have highlighted this compound as a candidate for therapy of osteoporosis. Moreover, SIRT1 antagonism enhances adipogenesis. There has been speculation that resveratrol can promote osteogenesis through SIRT1, but the mechanism remains unclear. In this study we investigated the molecular mechanism of how resveratrol can modulate the lineage commitment of human mesenchymal stem cells to osteogenesis other than adipogenesis. We found that resveratrol promoted spontaneous osteogenesis but prevented adipogenesis in human embryonic stem cell-derived mesenchymal progenitors. Resveratrol upregulated the expression of osteo-lineage genes RUNX2 and osteocalcin while suppressing adipo-lineage genes PPARg2 and LEPTIN in adipogenic medium. Furthermore, we found that the osteogenic effect of resveratrol was mediated mainly through SIRT1/FOXO3A with a smaller contribution from the estrogenic pathway. Resveratrol activated SIRT1 activity and enhanced FOXO3A protein expression, a known target of SIRT1, in an independent manner. As a result, resveratrol increased the amount of the SIRT1-FOXO3A complex and enhanced FOXO3A-dependent transcriptional activity. Ectopic overexpression or silencing of SIRT1/FOXO3A expression regulated RUNX2 promoter activity, suggesting an important role for SIRT1-FOXO3A complex in regulating resveratrol-induced RUNX2 gene transcription. Further mutational RUNX2 promoter analysis and chromatin immunoprecipitation assay revealed that resveratrol-induced SIRT1-FOXO3A complex bound to a distal FOXO response element (À1269/À1263), an action that transactivated RUNX2 promoter activity in vivo. Taken together, our results describe a novel mechanism of resveratrol in promoting osteogenesis of human mesenchymal stem cells by upregulating RUNX2 gene expression via the SIRT1/FOXO3A axis. ß

The multifunctional cytokine interleukin-6 (IL-6) regulates growth and differentiation of many cell types and induces production of acute-phase proteins in hepatocytes. Here we report that IL-6 protects hepatoma cells from apoptosis induced by transforming growth factor-␤ (TGF-␤), a well known apoptotic inducer in liver cells. Addition of IL-6 blocked TGF-␤-induced activation of caspase-3 while showing no effect on the induction of plasminogen activator inhibitor-1 and p15INK4B genes, indicating that IL-6 interferes with only a subset of TGF-␤ activities. To further elucidate the mechanism of this anti-apoptotic effect of IL-6, we investigated which signaling pathway transduced by IL-6 is responsible for this effect. IL-6 stimulation of hepatoma cells induced a rapid tyrosine phosphorylation of the p85 subunit of phosphatidylinositol 3-kinase (PI 3-kinase) and its kinase activity followed by the activation of Akt. Inhibition of PI 3-kinase by wortmannin or LY294002 abolished the protection of IL-6 against TGF-␤-induced apoptosis. A dominant-negative Akt also abrogated this anti-apoptotic effect. Dominant-negative inhibition of STAT3, however, only weakly attenuated the IL-6-induced protection. Finally, inhibition of both STAT3 and PI 3-kinase by treating cells overexpressing the dominant-negative STAT3 with LY294002 completely blocked IL-6-induced survival signal. Thus, concomitant activation of the PI 3-kinase/Akt and the STAT3 pathways mediates the anti-apoptotic effect of IL-6 against TGF-␤, with the former likely playing a major role in this anti-apoptosis.

Curcumin, widely used as a spice and coloring agent in food, possesses potent antioxidant, anti-inflammatory and anti-tumor promoting activities. In the present study, curcumin was found to induce apoptotic cell death in promyelocytic leukemia HL-60 cells at concentrations as low as 3.5 micrograms/ml. The apoptosis-inducing activity of curcumin appeared in a dose- and time-dependent manner. Flow cytometric analysis showed that the hypodiploid DNA peak of propidium iodide-stained nuclei appeared at 4 h after 7 micrograms/ml curcumin treatment. The apoptosis-inducing activity of curcumin was not affected by cycloheximide, actinomycin D, EGTA, W7 (calmodulin inhibitor), sodium orthovanadate, or genistein. By contrast, an endonuclease inhibitor ZnSO4 and proteinase inhibitor N-tosyl-L-lysine chloro-methyl ketone (TLCK) could markedly abrogate apoptosis induced by curcumin, whereas 12-O-tetradecanoylphorbol-13-acetate (TPA) had a partial effect. The antioxidants, N-acetyl-L-cysteine (NAC), L-ascorbic acid, alpha-tocopherol, catalase and superoxide dismutase, all effectively prevented curcumin-induced apoptosis. This result suggested that curcumin-induced cell death was mediated by reactive oxygen species. Immunoblot analysis showed that the level of the antiapoptotic protein Bcl-2 was decreased to 30% after 6 h treatment with curcumin, and was subsequently reduced to 20% by a further 6 h treatment. Furthermore, overexpression of bcl-2 in HL-60 cells resulted in a delay of curcumin-treated cells entering into apoptosis, suggesting that bcl-2 plays a crucial role in the early stage of curcumin-triggered apoptotic cell death.

The aggressiveness of a tumor is partly attributed to its resistance to chemotherapeutic agent-induced apoptosis. Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. Here we established a cell model system to examine whether stable expression of Cyr61 in MCF-7 cells can confer resistance to apoptosis and identify possible participating mechanisms. We showed that stable cell lines overexpressing Cyr61 had acquired a remarkable resistance to apoptosis induced by paclitaxel, adriamycin, and ␤-lapachone.

Transforming growth factor-␤ (TGF-␤