Hypoxia promotes C-X-C chemokine receptor type 4 expression through microRNA-150 in pancreatic cancer cells

Abstract

Abstract. Hypoxia promotes pancreatic cancer progression by triggering cancer cell invasion. However, the mechanism underlying this process remains unclear, hindering the development of effective therapies. The present study aimed to delineate the molecular mechanisms underlying the prometastatic effect of hypoxia in pancreatic cancer cells. The expression of microRNA-150 (miRNA-150) was detected using reverse transcription-quantitative polymerase chain reaction in pancreatic cancer samples and in the hypoxia-induced CaPan2 human pancreatic cancer cell line. The target gene was identified using bioinformatics and a luciferase reporter assay. Inhibition of the expression of C-X-C chemokine receptor type 4 (CXCR4) by miRNA-150 was confirmed using transfection with miRNA-150 mimics. The prometastatic effect of hypoxia was detected using migration assays. The expression of miRNA-150 was shown to be downregulated in pancreatic cancer samples compared with that in normal pancreatic tissue samples. Furthermore, its expression was reduced in hypoxia-induced CaPan2 cells, compared with that in control cells. Bioinformatics and the results of the luciferase reporter assay, demonstrated that miRNA-150 inhibited the expression of CXCR4 by directly targeting the 3' untranslated region of CXCR4 mRNA. The results of the migration assay showed that hypoxia promotes cell migration and invasion. However, this prometastatic effect was reversed by transfection with miRNA-150 mimics. The present results suggest that hypoxia promotes pancreatic cancer migration by downregulating miRNA-150. IntroductionPancreatic cancer (PC) is among the most lethal malignancies, with a high incidence and rate of metastasis (1). At the time of diagnosis, the majority of patients are at an advanced stage of disease, with multi-organ metastasis, which indicates a poor prognosis for digestive system tumors (2). It is challenging to diagnose PC at an early stage, which results in a low 5-year survival rate; only 4% of patients diagnosed with pancreatic cancer survive after 5 years in China (3). Therefore, the identification of novel gene targets, which are differentially expressed in PC and functionally involved in the development of malignant phenotypes, is required in order to enable early diagnosis and the development of effective therapeutic strategies.Hypoxia is an important characteristic of solid tumors. As a tumor increases in size, it quickly outgrows its blood supply, leaving regions of the tumor, in which the oxygen concentration is significantly lower than that in normal tissues. In order to support tumor growth and proliferation within hypoxic environments, the expression of a number of genes is altered, and changes in metabolism also occur (4). Recently, a novel class of endogenous small non-coding regulatory RNAs, termed microRNAs (miRNAs), has received increasing attention. These small molecules exert their regulatory effects by base pairing with partially complementary messenger RNAs (mRNAs). They act via one of two mechanisms: Degradatio...

Targeting hypoxic tumor microenvironment in pancreatic cancer

“…Figure 3 depicts the effects of microenvironmental remodeling on PC progression under hypoxic conditions. [104] miR-142 Down miR-142-HIF-1α-vimentin, VEGF-C, E-cadherin Inhibits proliferation, EMT, and invasion [184] miR-150 Down miRNA-150-CXCR4 Inhibits migration and invasion [185] miR-519 Down miR-519-PD-L1 Inhibits cell invasiveness, and induces apoptosis [186] miR-548an Down HIF-1α-HDAC1-miR-548an-vimentin Inhibits the proliferation and invasion [187] Pathological angiogenesis under hypoxia…”

The Effect of Hypoxia on the Expression of CXC Chemokines and CXC Chemokine Receptors—A Review of Literature

“…Chronic hypoxia increases the expression of CXCR4 in tumor cells such as breast cancer cells ( Figure 4 ) [ 233 , 234 , 235 , 236 , 237 , 238 ], chondrosarcoma cells [ 239 , 240 ], clear cell-renal cell carcinomas cells [ 223 ], chronic lymphocytic leukemia [ 241 ], colon cancer cells [ 62 , 242 , 243 ], gastric cancer cells [ 212 , 244 ], glioblastoma multiforme cells [ 226 , 245 , 246 , 247 ], GOT1 cells (ileal carcinoids) [ 221 ], lung cancer cells [ 248 , 249 ], melanoma cells [ 250 , 251 ], multiple myeloma cells [ 252 ], oral squamous cell carcinoma cells [ 253 ], osteosarcoma cells [ 254 , 255 ], pancreatic ductal adenocarcinoma cells [ 256 , 257 ], renal cell carcinoma cells [ 258 ], and retinoblastoma cells [ 259 ]. However, chronic hypoxia does not universally induce CXCR4 expression in tumor cells—for example, in hepatocellular carcinoma cells it only increases the expression of CXCR4 in some cell lines [ 260 ].…”

“…In breast cancer cells, chronic hypoxia increases CXCR4 expression independently of HIF-1, depending only on NF-κB [ 233 ]. Chronic hypoxia increases the expression of CXCR4 in the pancreatic ductal adenocarcinoma cell line by reducing the level of miRNA-150 [ 257 ]. In chondrosarcoma, chronic hypoxia increases the expression of miRNA-181a, which controls the expression of the regulator of G-protein signaling 16 (RGS16) [ 240 , 268 ].…”

“…At the same time, a chronic hypoxia-induced increase in CXCR4 expression stimulates the proliferation of cancer cells [ 256 , 275 ] and causes their migration and invasion [ 244 , 246 , 248 , 249 , 255 , 256 , 257 , 275 ], especially in combination with the chronic hypoxia-induced increase in CXCL12 expression in tumor cells [ 167 , 223 , 228 ]. The upregulation of CXCR4 also aids in the transendothelial migration of cancer cells [ 229 ], which is followed by the invasion of cancer cells to neighboring tissues and organs [ 253 , 276 , 277 , 278 ].…”

The Association of Residential Altitude on the Molecular Profile and Survival of Melanoma: Results of an Interreg Study

“…In vivo experiments also demonstrated the relationship between UV exposure and the downregulation of miR-155-5p in the development of squamous cell carcinoma (SCC) [ 25 , 26 ]. Furthermore, in vitro studies have shown that miR-150-5p is downregulated by hypoxia in pancreatic cell lines [ 27 ]. Nevertheless, the above-mentioned miRNAs have been described as favorable biomarkers in skin melanomas or as tumor suppressor miRNAs [ 9 , 14 , 28 , 29 ].…”