CXCL3 overexpression promotes the tumorigenic potential of uterine cervical cancer cells via the MAPK/ERK pathway.

CXCL3 belongs to the CXC-type chemokine family and is known to play a multifaceted role in various human malignancies. While its clinical significance and mechanisms of action in uterine cervical cancer (UCC) remain unclear. This investigation demonstrated that the UCC cell line HeLa expressed CXCL3, and strong expression of CXCL3 was detected in UCC tissues relative to nontumor tissues. In addition, CXCL3 expression was strongly correlated with CXCL5 expression in UCC tissues. In vitro, HeLa cells overexpressing CXCL3, HeLa cells treated with exogenous CXCL3 or treated with conditioned medium from WPMY cells overexpressing CXCL3, exhibited enhanced proliferation and migration activities. In agreement with these findings, CXCL3 overexpression was also associated with the generation of HeLa cell tumor xenografts in athymic nude mice. Subsequent mechanistic studies demonstrated that CXCL3 overexpressing influenced the expression of extracellular signal-regulated kinase (ERK) signaling pathway associated genes, including ERK1/2, Bcl-2, and Bax, whereas the CXCL3-induced proliferation and migration effects were attenuated by exogenous administration of the ERK1/2 blocker PD98059. The data of the current investigation support that CXCL3 appears to hold promise as a potential tumor marker and interference target for UCC.

Involvement of protein kinase A activation and phospholipase A(2) inhibition in the adenosine-activated basolateral 50 pS K(+) channels in the thick ascending limb of the rat kidney.

The present study was designed to investigate the role of protein kinase A (PKA) and phospholipase A(2) (PLA(2)) in the stimulating effect of adenosine on the basolateral 50 pS K(+) channels in the thick ascending limb (TAL) of the rat kidney. Under the anatomic microscope, the TAL was dissected. The current of 50 pS K(+) channels were recorded by patch clamp technology. The protein expression of phosphorylated PKA and phosphorylated PLA(2) were examined by Western blot. The results showed that cyclohexyladenosine (CHA), an analog of adenosine, increased the 50 pS K(+) channel activity (P < 0.05). In the presence of H8, an antagonist of PKA, CHA did not affect the 50 pS K(+) channel activity. In the presence of AACOCF3 (an antagonist of PLA(2)), CHA did not further increase the 50 pS K(+) channel activity. CHA increased phosphorylation level of PKA, whereas inhibited phosphorylation of PLA(2) in the TAL of the rat kidney (P < 0.01). Furthermore, after blocking the PLA(2) with AACOCF3, CHA still increased the expression of phosphorylated PKA. On the contrary, CHA did not obviously change the expression of phosphorylated PLA(2) after H8 pretreatment. The results suggest that the stimulation of basolateral 50 pS K(+) channels by CHA is mediated by the activation of PKA followed by the inhibition of PLA(2) in the TAL of the rat kidney.

Overexpression of CXCL3 can enhance the oncogenic potential of prostate cancer.

PURPOSE: CXCL3 and its receptor CXCR2 were considered to play particularly important roles in the progression of malignancies. However, the investigations about CXCL3/CXCR2 axis in prostate cancer have been poorly involved. Herein we firstly reported our studies on the expression and biological roles of CXCL3 and CXCR2 in prostate cancer. METHODS: Expression levels of CXCL3 and CXCR2 in prostate cancer cell lines (PC-3, DU145 and LNCaP), immortalized prostate stromal cell line (WPMY-1) and immortalized prostate epithelial cell line (RWPE-1) were investigated by RT-PCR, ELISA and western blot, whereas expression levels of CXCL3 in a prostate tissue microarray were detected by immunohistochemistry. Cell counting kit-8 and transwell assays were, respectively, utilized to determine the effects of exogenous CXCL3 on the cell proliferation and migration. We further examined whether CXCL3 could regulate the expression of genes correlated with prostate tumorigenesis by RT- PCR. RESULTS: Elevated expression of CXCR2 was detected in DU145, LNCaP and RWPE-1. Moreover, high-level CXCL3 can be secreted by PC-3 and RWPE-1, and CXCL3 protein expression level in tissue microarray is concordant with prostate cancer metastasis. Exogenous CXCL3 does not contribute to proliferation, but has a significant effect on migration of prostate cancer cells and RWPE-1. Finally, our data showed that exogenous CXCL3 can regulate the expression of genes including ERK, TP73, NUMB, BAX and NDRG3. CONCLUSION: Our findings suggest that CXCL3 and its receptor CXCR2 are overexpressed in prostate cancer cells, prostate epithelial cells and prostate cancer tissues, which may play multiple roles in prostate cancer progression and metastasis.