ag-490 and Adenocarcinoma

Use of enzalutamide has improved the treatment of advanced prostate cancer. However, resistance to enzalutamide can develop frequently in initial responders. This study aimed to test whether overexpression of IL-6 and constitutive activation of Stat3 in prostate cancer cells increase resistance to enzalutamide.. Sensitivity of prostate cancer cells to enzalutamide was tested using cell growth assays and clonogenic assays. Quantitative reverse transcription-PCR, ELISA, and Western blotting were performed to detect expression levels of IL-6, c-Myc, survivin, and AR. Expression of Stat3 was downregulated using siRNA specific to Stat3. ChIP assay was performed to examine recruitment of AR to the PSA promoter.. Prostate cancer cells expressing autocrine IL-6 are resistant to enzalutamide and autocrine IL-6 leads to constitutive activation of Stat3 and its target genes. Down regulation of Stat3 led to an increase in sensitivity of prostate cancer cells to enzalutamide. Overexpression of constitutively active Stat3 in prostate cancer cells induced resistance to enzalutamide treatment. Constitutively active Stat3 also enhanced the recruitment of AR to PSA promoter which could not be disrupted by enzalutamide. The Stat3 inhibitor AG490 reversed enzalutamide resistance in prostate cancer cells, while combination treatment with enzalutamide and AG490 significantly inhibited cell growth and induced cell apoptosis.. This study demonstrates that the autocrine IL-6 pathway induces enzalutamide resistance in prostate cancer cells via the constitutive activation of Stat3. Co-targeting IL6-Stat3 pathway with enzalutamide may be utilized for treatment of advanced prostate cancer.

Topics: Adenocarcinoma; Antineoplastic Agents; Apoptosis; Benzamides; Cell Line, Tumor; Down-Regulation; Drug Resistance, Neoplasm; Enzyme Inhibitors; Humans; In Vitro Techniques; Interleukin-6; Male; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; RNA, Small Interfering; Signal Transduction; STAT3 Transcription Factor; Tyrphostins

Cancer cachexia syndrome is observed in 80% of patients with advanced-stage cancer, and it is one of the most frequent causes of death. Severe wasting accounts for more than 80% in patients with advanced pancreatic cancer. Here we wanted to define, by using an microarray approach and the Pdx1-cre;LSL-Kras(G12D) ;INK4a/arf(fl/fl) mice model, the pathways involved in muscle, liver, and white adipose tissue wasting. These mice, which develop systematically pancreatic cancer, successfully reproduced many human symptoms afflicted with this disease, and particularly cachexia. Using the profiling analysis of pancreatic cancer-dependent cachectic tissues we found that Jak2/Stat3 pathways, p53 and NFkB results activated. Thus, our interest was focused on the Jak2 pathways because it is pharmacologically targetable with low toxicity and FDA approved drugs are available. Therefore, Pdx1-cre;LSL-Kras(G12D) ;INK4a/arf(fl/fl) mice were treated with the Jak2 inhibitor AG490 compound daily starting at 7 weeks old and for a period of 3 weeks and animals were sacrificed at 10 weeks old. Body weight for control mice was 27.84 ± 2.14 g, for untreated Pdx1-cre;LSL-Kras(G12D) ;INK4a/arf(fl/fl) was 14.97 ± 1.99 g, whereas in animals treated with the AG490 compound the weight loss was significantly less to 24.53 ± 2.04 g. Treatment with AG490 compound was efficient since phosphorylation of Jak2 and circulating interleukin-6 (IL6) levels were significantly reduced in cachectic tissues and in mice respectively. In conclusion, we found that Jak2/Stat3-dependent intracellular pathway plays an essential role since its pharmacological inhibition strongly attenuates cachexia progression in a lethal transgenic pancreatic cancer model.

Topics: Adenocarcinoma; Adipose Tissue, White; Animals; Body Weight; Cachexia; Gene Expression Profiling; Interleukin-6; Janus Kinase 2; Liver; Mice; Mice, Transgenic; Muscle, Skeletal; Pancreatic Neoplasms; Phosphorylation; Protein Kinase Inhibitors; Signal Transduction; STAT3 Transcription Factor; Time Factors; Tyrphostins

In the present study, the effect of radiation on the invasion of the pulmonary adenocarcinoma cell line, A549, was investigated. Invasion of A549 cells irradiated with 2 and 4 Gy doses of γ‑ray was detected using the transwell Matrigel invasion assay. Levels of matrix metalloproteinase 2 (MMP‑2) and phosphorylated signal transducer and activator of transcription 3 (STAT3) were detected by reverse transcription PCR (RT-PCR) and/or immunoblotting. The enzyme activity of MMP‑2 was examined by gelatin zymography. Results demonstrated that the invasion of A549 cells was significantly enhanced by γ‑ray radiation at doses of 2 or 4 Gy. In addition, exposure to radiation was found to promote transcriptional expression of MMP‑2 and increase MMP‑2 enzyme activity. Irradiation activated the phosphorylation of STAT3 and promoted the nuclear localization of STAT3. The blockage of STAT3 phosphorylation using a specific inhibitor (AG490) suppressed the irradiation‑induced elevation of MMP‑2 expression, enzyme activity and invasion of A549 cells. Finally, the expression of vascular endothelial growth factor (VEGF) was found to be upregulated by radiation, which was associated with the activation of STAT3. Results of the current study indicate that irradiation leads to activation of STAT3 and translocation to the nucleus, leading to activation of VEGF and MMP‑2 transcription, resulting in the increased invasion of A549 cells.

Topics: Adenocarcinoma; Cell Line, Tumor; Cell Movement; Gamma Rays; Humans; Lung Neoplasms; Matrix Metalloproteinase 2; Phosphorylation; STAT3 Transcription Factor; Tyrphostins; Up-Regulation; Vascular Endothelial Growth Factor A

Obesity is an established risk factor for endometrial cancer. Leptin, a secreted protein of the ob gene by white adipose tissue, plays an important role in the regulation of food intake and energy consumption in the brain and acts as a potential growth stimulator in normal and neoplastic cancer cells. However, a direct role for leptin in endometrial cancer has not been demonstrated. In the present study, the effect of leptin on the proliferation of Ishikawa endometrial cancer cells was investigated as well as the possible mechanism(s) underlying this action in endometrial cancers which express both short and long isoforms of leptin receptors. The expression of leptin receptor (ObRb) in Ishikawa cells was detected by RT-PCR and Western blotting. The cells after serum starvation, were treated by leptin with various concentrations (0, 10, 50, 100, 150 ng/mL) for different durations (6, 12, 24 h). The effect of leptin treatment on cell proliferation was examined by MTT assay. Meanwhile, inhibitory effect of Janus tyrosine kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) inhibitor AG490 or extracellular signal-regulated kinase 1/2 (ERK1/2) inhibitor PD98059 on the proliferation of Ishikawa cells induced by leptin was also studied. Ishikawa cells were treated with 100 ng/mL leptin for various periods (0, 20, 40, 60 min), and the levels of STAT3 phosphorylation and ERK1/2 phosphorylation were examined by Western blotting. The results showed that leptin induced the phosphorylation of STAT3 and the activation of ERK1/2 in a time- and dose-dependent manner in the Ishikawa endometrial cancer cells. Blocking STAT3 phosphorylation with the inhibitor AG490, or blocking ERK1/2 activation by the specific ERK1/2 kinase inhibitor, PD98059, abolished leptin-induced proliferation of Ishikawa cells. In addition, leptin was found to potently induce the invasion of endometrial cancer cells in a Matrigel invasion assay. Leptin-stimulated invasion was effectively blocked by pharmacological inhibitors of STAT3 (AG490) and ERK1/2 kinase (PD98059). These results suggested that leptin promotes endometrial cancer growth and invasiveness by activating STAT3 and ERK1/2 signaling pathways and therefore blocking its action at the receptor level can be a rational therapeutic strategy.

Topics: Adenocarcinoma; Cell Line, Tumor; Cell Proliferation; Endometrial Neoplasms; Enzyme Inhibitors; Female; Flavonoids; Humans; Leptin; MAP Kinase Signaling System; Neoplasm Invasiveness; STAT3 Transcription Factor; Tyrphostins

We previously reported that matrix metalloproteinase (MMP)-10 mRNA levels were significantly lower in tumor tissues than in adjacent normal tissues in human non-small cell lung cancer (NSCLC), whereas protein levels of MMP-10 were higher in the tumor tissues than the adjacent tissues. The mechanism of this divergence is still unknown. In the present study the role of Janus kinase 2/signal transducers and activators of transcription 3 (JAK2/STAT3) on interleukin (IL)-6 mediated regulation of MMP-10 expression was investigated in a human lung adenocarcinoma cell line (A549 cells) and the molecular regulatory mechanism of MMP-10 expression was explored. A549 cells were stimulated by different concentrations of IL-6 with or without AG490, a specific JAK2 inhibitor. It was demonstrated that IL-6 moderately reduced the MMP-10 mRNA levels, whereas it significantly enhanced the MMP-10 protein mass in the A549 cells. This phenomenon mimicked the divergence of mRNA level and protein mass of MMP-10 in human NSCLC. Moreover, the present study indicated that IL-6 regulation of MMP-10 expression was via the JAK2/STAT3 pathway. STAT3 mRNA levels were significantly increased when the cells were treated with IL-6, whereas when AG490 (50 muM) was added to the cell cultures, IL-6-induced increase of STAT3 mRNA levels was abolished. Meanwhile, AG490 blocked the IL-6-induced inhibition of MMP-10 mRNA as well as blocking the IL-6-induced increase of MMP-10 protein mass in the A549 cells. Neither IL-6 nor AG490 influenced JAK2 mRNA levels in the A549 cell cultures. It is concluded that the JAK2/STAT3 pathway is involved in the IL-6-mediated regulation of MMP-10, and IL-6 can moderately reduce MMP-10 mRNA levels and strongly increase MMP-10 protein mass in human lung adenocarcinoma A549 cells. Contrasting effects of IL-6 on MMP-10 mRNA level and protein concentration in A549 cells may partially explain the divergence of MMP-10 mRNA level and protein mass in human NSCLC.

Topics: Adenocarcinoma; Cell Line, Tumor; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Interleukin-6; Janus Kinase 2; Lung Neoplasms; Matrix Metalloproteinase 10; RNA, Messenger; Signal Transduction; STAT3 Transcription Factor; Tyrphostins