ag-490 and Carcinoma

To determine the effect of JAK kinase inhibitor AG490 on proliferation and apoptosis of nasopharyngeal carcinoma cell line C666-1 and explore the inhibitory effect of AG490 on STAT3 signal transduction pathway.. An experimental study.. Xi'an Ninth Hospital, Xi'an, China, from May 2015 to December 2016.. AG490 was applied to C666-1 cells. Cell proliferation was detected by MTTassay. Cell cycle and apoptosis were detected by flow cytometry. The expression of STAT3 and p-STAT3 protein was detected by immobilized Western blot.. AG490 could effectively inhibit proliferation of C666-1 cellsin vitro, and the inhibitory effect was characterized by time and concentration dependence. AG490 induced apoptosis of nasopharyngeal carcinoma cells, and apoptosis rate increased with prolongation of the time. AG490 could inhibit expression of STAT3 and p-STAT3 protein in C666-1 cells.. AG490 can down-regulate expression of STAT3 and p-STAT3 protein in C666-1 cells, inhibit proliferation of nasopharyngeal carcinoma cells and promote apoptosis of nasopharyngeal carcinoma cells.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma; Cell Cycle; Cell Proliferation; Flow Cytometry; Gene Expression Regulation, Neoplastic; Humans; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

Signal transducer and activator of transcription 3 (STAT3) has oncogenic potential. The biological effects of STAT3 have not been studied extensively in the pathogenesis of colon cancer, nor has the role of Janus kinase 3 (JAK3), the physiological activator of STAT3, been evaluated. Here, we demonstrate that activated STAT3 (pSTAT3) and activated JAK3 (pJAK3) are expressed constitutively in two colon cancer cell lines, SW480 and HT29. To evaluate the significance of JAK3/STAT3 signaling, we inhibited JAK3 with AG490 and STAT3 with a dominant-negative construct. Inhibition of JAK3 down-regulated pSTAT3. The blockade of JAK3/STAT3 signaling significantly decreased viability of colon cancer cells due to apoptosis and cell-cycle arrest through down-regulation of Bcl-2, Bcl-X(L), Mcl-1, and cyclin D2 and up-regulation of p21(waf1/cip1) and p27(kip1). We also examined histological sections from 22 tumors from patients with stage II or stage IV colon cancer and found STAT3, JAK3, and their activated forms to be frequently expressed. Furthermore, quantitative reverse transcriptase-polymerase chain reaction identified JAK3 mRNA in colon cancer cell lines and primary tumors. Our findings illustrate the biological importance of JAK3/STAT3 activation in the oncogenesis of colon cancer and provide novel evidence that JAK3 is expressed and contributes to STAT3 activation in this malignant neoplasm.

Topics: Aged; Apoptosis; Carcinoma; Cell Cycle; Cell Line, Tumor; Cell Survival; Colonic Neoplasms; Cyclin D2; Cyclin-Dependent Kinase Inhibitor p21; Cyclins; Enzyme Activation; Enzyme Inhibitors; Female; Gene Expression Regulation, Neoplastic; HT29 Cells; Humans; Immunohistochemistry; Janus Kinase 3; Male; Middle Aged; Neoplasm Staging; Protein-Tyrosine Kinases; Proto-Oncogene Proteins c-bcl-2; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Signal Transduction; Tyrphostins

Ovarian cancer is the leading cause of death from gynecologic malignancies in the United States. In an attempt to develop drugs that suppress ovarian cancer cells, we examined the effect of selective inhibitors of protein tyrosine kinases-tyrphostins, which are likely to play a role in ovarian cancer cells.. We examined the cellular and biochemical effects of tyrphostins AG1478, PP2, AGL2592, and AG490 from four different families on the ovarian carcinoma cell line OV1063.. We found that the AG1478, PP2, AGL2592, and AG490 tyrphostins suppressed cell proliferation and altered cell cycle distribution of the OV1063 cells in a dose- and time-dependent manner. Immunoblotting analysis indicated that AG1478 effectively inhibited epidermal growth factor receptor autophosphorylation, that AG490 decreased the level of Jak2 and phosphorylated Stat3, and that PP2 decreased the level of pp60Src protein. AGL2592 decreased the level of constitutive activated epidermal growth factor receptor and pStat3, but its molecular targets have not been identified completely.. The growth-arresting properties of these tyrphostins identify them as possible candidates for signal transduction therapy.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma; Catechols; Cell Cycle; Cell Division; Dose-Response Relationship, Drug; Enzyme Inhibitors; Female; Humans; Nitriles; Ovarian Neoplasms; Protein Kinase Inhibitors; Pyrimidines; Quinazolines; Time Factors; Tumor Cells, Cultured; Tyrphostins

Disruption of apoptosis may allow metastatic cell survival and confer resistance to chemotherapeutic drugs. We have analysed the molecular pathways that activate these survival genes in specific sites of metastasis. Estrogen receptor-negative breast cancer cell line MDA-MB435 and two metastatic sublines derived from lung (435L) and brain (435B) were analysed for the expression of members of the Bcl-2 family of apoptosis regulators. The levels of Bcl-2 were higher in the metastatic sublines than in parental cells, which correlated with the activation of Stat3, but not with the expression and/or activation of known bcl-2 transcription factors (CREB and WT1). In the brain subline, both expression of Bcl-2 and Stat3 activation were induced by epidermal growth factor and abrogated after treatment with kinase inhibitors specific for epidermal growth factor receptor or Jak2. Furthermore, transfection of 435B with a dominant-negative Stat3 markedly reduced the expression of Bcl-2 protein, whereas transient expression of a constitutively active Stat3 increased Bcl-2 in parental 435 cells. In addition, blockade of Stat3 activation by treatment with epidermal growth factor receptor and Jak2 kinase inhibitors or transfection with a dominant negative Stat3, sensitizes 435B cells to chemotherapy-induced apoptosis. Our data suggest that an increased activation of the Stat3-Bcl-2 pathway in estrogen receptor-negative metastatic breast cancer cell lines confer a survival advantage to these cells and contribute to their chemoresistance.

Topics: Antineoplastic Agents; Apoptosis; bcl-X Protein; Brain Neoplasms; Breast Neoplasms; Carcinoma; Cyclic AMP Response Element-Binding Protein; DNA-Binding Proteins; Enzyme Inhibitors; ErbB Receptors; Female; Humans; Janus Kinase 2; Lung Neoplasms; Neoplasm Metastasis; Neoplasms, Hormone-Dependent; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-bcl-2; Receptors, Estrogen; STAT3 Transcription Factor; Trans-Activators; Transcription, Genetic; Tumor Cells, Cultured; Tyrphostins

We investigated the role of autocrine production of human (h) GH in the attachment and spreading of mammary carcinoma cells in vitro. We used a previously described model system for the study of the autocrine/paracrine role of GH in which the hGH gene (MCF-hGH) or a translation-deficient hGH gene (MCF-MUT) was stably transfected into MCF-7 cells. No differences in attachment to a collagen matrix between MCF-hGH and MCF-MUT cells were observed in either serum-free medium (SFM) or medium containing exogenous hGH, 5% serum, or 10% serum. In contrast, MCF-hGH cells spread more rapidly on a collagen matrix than did MCF-MUT cells. Exogenous hGH and 10% serum interacted with autocrine production of hGH in an additive manner to increase cell spreading. MCF-hGH cells formed filipodia and stress fibers earlier than MCF-MUT cells during the process of cell spreading and possessed marked differences in morphology after spreading. MCF-MUT cells displayed uniform and symmetrical formation of stress fibers, whereas MCF-hGH cells displayed irregular and elongated stress fiber formation. The level of cytoplasmic phosphotyrosine was increased in MCF-hGH compared with MCF-MUT cells during spreading and displayed colocalization with Janus kinase 2 (JAK2). Basal JAK2 tyrosine phosphorylation was increased, and it increased further on spreading in MCF-hGH cells compared with MCF-MUT cells. Transient transfection of JAK2 complementary DNA resulted in interaction with autocrine hGH to increase the rate of cell spreading in MCF-hGH cells compared with MCF-MUT cells. Treatment with a selective JAK2 tyrosine kinase inhibitor (AG 490) reduced the rate of MCF-hGH cell spreading to the rate of MCF-MUT cell spreading. Thus, we conclude that autocrine production of hGH enhances the rate of mammary carcinoma cell spreading in a JAK2-dependent manner.

Topics: Actins; Autocrine Communication; Breast Neoplasms; Carcinoma; Cell Adhesion; Enzyme Inhibitors; Female; Growth Hormone; Hormone Antagonists; Human Growth Hormone; Humans; Janus Kinase 2; Phosphorylation; Phosphotyrosine; Protein-Tyrosine Kinases; Proto-Oncogene Proteins; Receptors, Somatotropin; Recombinant Proteins; Tissue Distribution; Tumor Cells, Cultured; Tyrosine; Tyrphostins