Low concentration arsenite activated JAK2/STAT3 signal and increased proliferative factor expressions in SV-HUC-1cells after short and long time treatment

Lipopolysaccharide-Educated Cancer-Associated Fibroblasts Facilitate Malignant Progression of Ovarian Cancer Cells via the NF-kB/IL-6/JAK2 Signal Transduction

Gram-negative bacteria increase in ovarian cancer (OC) tissues, but its association with OC progression remains largely unknown. The present study aimed to investigate whether and how cancer-associated fibroblasts (CAFs) pretreated by the main components of bacterial outer membrane lipopolysaccharide (LPS) influence the malignancy of OC cells. Specifically, the culture medium of LPS-preconditioned CAFs (LPS-CM) further accelerated cell proliferation, colony formation and tumorigenesis of OC cells SKOV3 and HEY A8, compared with culture medium of CAFs. Next, we found that LPS pretreatment activated the nuclear factor-kappa B (NF-kB) pathway in CAFs to secret cytokines, including interleukin 1β (IL-1β), interleukin 6 (IL-6), vascular endothelial growth factor (VEGF), etc. Neutralization of IL-6 in LPS-CM abolished the promoting effect of LPS-CM on cell proliferation, survival and epithelial-mesenchymal transition (EMT) in SKOV3 and HEY A8 cells. Mechanistically, LPS-CM activated the Janus kinases 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway, while application with JAK2 inhibitor also reversed the promoting effect of LPS-CM on malignancy of OC cells. In summary, LPS-pretreated CAFs IL-6-dependently accelerate OC progression via activating the JAK2/STAT3 signal pathway, which enriches our understanding of the molecular mechanisms underlying ovaries-colonized gram-negative bacteria in OC progression.

JAK2/STAT3 in role of arsenic-induced cell proliferation: a systematic review and meta-analysis

OBJECTIVES

Malignant cell proliferation is one of the important mechanisms of arsenic poisoning. A large number of studies have shown that STAT3 plays an important role in cell malignant proliferation, but there are still many contradictions in the effect of arsenic on JAK2/STAT3. This study aims to explore the role of JAK2/STAT3 in arsenic-induced cell proliferation.

METHODS

By taking normal cells as the research object and using Standard Mean Difference (SMD) as the effect size, meta-analysis was used to explore the effect of arsenic on JAK2/STAT3. Then, the dose-effect Meta was used to further clarify the dose-effect relationship of arsenic on JAK2/STAT3.

RESULTS

Through meta-analysis, this study found that arsenic could promote the phosphorylation of STAT3 (SMD=4.21, 95%CI [1.05, 7.37]), and increase IL-6 and p-JAK2, Vimentin, VEGF expression levels, thereby inducing malignant cell proliferation. In addition, this study also found that arsenic exposure dose (<5 μmol m^-3), time(<24 h) and cell type were important sources of heterogeneity in the process of exploring the effects of arsenic on p-STAT3, IL-6 and p-JAK2. Dose-effect relationship meta-analysis results showed that arsenic exposure significantly increased the expression level of IL-6. When the arsenic exposure concentration was less than 7 μmol m^-3, the expression level of p-JAK2 upregulated significantly as the arsenic exposure concentration gradually increasing. Moreover, the expression level of p-STAT3 elevated significantly with the gradual increase of the arsenic concentration under 5 μmol m^-3 of arsenic exposure, but the expression level of p-STAT3 gradually decreases when the concentration is greater than 5 μmol m^-3.

CONCLUSIONS

Exposure to low dose of arsenic could promote the expression of JAK2/STAT3 and induce the malignant proliferation of cells through upregulating IL-6, and there was dose-effect relationship among them.

Ginkgolide K promotes angiogenesis in a middle cerebral artery occlusion mouse model via activating JAK2/STAT3 pathway

Ginkgolide K (GK) is a new compound extracted from the leaves of Ginkgo biloba, which has been recognized to exert anti-oxidative stress and neuroprotective effect on ischemic stroke. While whether it plays an enhanced effect on angiogenesis during ischemic stroke remains unknown. The aim of this study was to investigate the effect of ginkgolide K on promoting angiogenesis as well as the protective mechanism after cerebral ischemia-reperfusion. Using the transient middle cerebral artery occlusion (tMCAO) mouse model, we found that GK (3.5, 7.0, 14.0 mg/kg, i.p., bid., 2 weeks) attenuated neurological impairments, and promoted angiogenesis of injured ipsilateral cortex and striatum after 14 days of cerebral ischemia-reperfusion in mice. Further, GK (3.5 mg/kg in vivo, 10 μM in vitro) significantly up-regulated the expressions of HIF-1α and VEGF in tMCAO mouse brains and in b End3 cells after OGD/R, and GK-induced upregulation of HIF-1α and VEGF in b End3 cells could be abolished by JAK2/STAT3 inhibitor AG490. Our results demonstrate that GK promotes angiogenesis after ischemia stroke through increasing the expression of HIF-1α/VEGF via JAK2/STAT3 pathway, which provide an insight into the novel clinical application of GK and its analogs in ischemic stroke therapy in future.

Arsenite increases Cyclin D1 expression through coordinated regulation of the Ca2+/NFAT2 and NF-κB pathways via ERK/MAPK in a human uroepithelial cell line

To understand the direct link between Cyclin D1, and nuclear factor of activated T cells 2 (NFAT2) and nuclear factor (NF)-κB in arsenic-treated bladder cells, as well as the association between MAPK and NFAT signaling, we determined whether or not the Ca²⁺/NFAT pathway is activated in an arsenic-treated normal urothelial cell line and determined the roles of NFAT and NF-κB signals in the regulation of Cyclin D1 expression. The SV-40 immortalized human uroepithelial cell line, SV-HUC-1, was treated with NaAsO₂ for 24 h (0, 1, 2, 4, 8, and 10 μM) and 10, 20, 30, and 40 weeks (0 and 0.5 μM). We found that arsenite increased the intracellular Ca²⁺ levels and induced NFAT2 nuclear translocation after treatment for 24 h. The level of NFAT2 mRNA and expression of total protein and nuclear protein were increased after long-term treatment with 0.5 μM arsenite for 30 and 40 weeks compared to the cells treated for 24 h. In addition, NF-κB p50 and p65 nuclear protein expression increased significantly in cells treated with 2-8 μM arsenite for 24 h, which was consistent with NFAT2 nuclear expression. Furthermore, an ERK inhibitor (U0126) significantly reduced the expression of NFAT2 nuclear protein, and an ERK and JNK inhibitor decreased the levels of p65 and p50 nuclear protein. Cyclin D1 is known as a proto-oncogene and the level of this protein was increased in SV-HUC-1 cells treated with arsenite for 24 h and long-term. An NFAT inhibitor (CsA) and NF-κB inhibitor (PDTC) all markedly reduced Cyclin D1 protein expression. Treatment with U0126 also significantly decreased Cyclin D1 protein expression while JNK and p38 inhibitors did not attenuate the arsenite-associated increase in Cyclin D1 protein expression. The results suggest that regulation of Cyclin D1 protein expression by arsenite in SV-HUC-1 cells is dependent on ERK/NFAT2 and ERK/NF-κB, but is not dependent on JNK or p38.

HER2 and Src co-regulate proliferation, migration and transformation by downstream signaling pathways in arsenite-treated human uroepithelial cells

HER2 mediate proliferation, migration and transformation by multiple downstream signaling pathways in arsenite-treated human uroepithelial cells.