S2026 Heat Shock Protein 47 Regulates Expression of Collagen V and TIMP2 in Pancreatic Cancer Cells

(Introduction) Heat Shock Protein 47 (HSP 47) is a collagen-specific (collagen type I-V) chaperone molecular residing in the endoplasmic reticulum (ER) and it has been thought to be a marker of fibroblasts. It was reported that HSP 47 was expressed in cancer cells as well as fibroblasts of pancreatic cancer tissues. However, its function in cancer cells has not been investigated. (Materials and Methods) In order to investigate the presence of HSP 47 and collagen type I-V in human pancreatic cancer tissues, immunohistochemistry was performed. Expression of HSP 47 in pancreatic cancer cell lines, KMP-4,-5 and -6cells, was examined by western blot. Colocalization of HSP 47 and collagens ( type I-V ) were investigated by double immunofluorostaining. To deplete the expression of HSP 47 in cells, two kinds of siRNAs were transfected. At 120 h after transfection, attached cell number were assayed by CyQuant assay kit. Cell invasion ability was assay with Matrigel coated culture insert system. Expression of MMP -2, -9, TIMP-1, and -2 and collagens were examined by QRT-PCR. (Results) In 3 of 4 pancreatic cancer tissues, cancer cells were HSP47 positive. In one of 4 tissues, HSP47 was negative. In one metastatic lymph node, cancer cells was HSP 47 negative. Among collagens, immunoreactivity for collagen V was found in pancreatic cancer cells. Immunofluorostaining in cells showed that HSP 47 colocalize with collagen type V. At 120 h after transfection of siRNA into KMP-6 cells, attached cell number was not affected by depletion of HSP47. Cell invasion assay showed that depletion of HSP47 reduce migration cells. Expression of MMP -2, -9 and TIMP-1 at the RNA levels were not affected by depletion of HSP 47, but that of collagen type V and TIMP-2 was reduced by 70% and 40% of control, respectively. (Conclusion) HSP47 colocalize with collagen type V and regulates gene expression of collagen V in pancreatic cancer cells. HSP47 depletion downregulated expression of TIMP2 of cancer cells, but not affect cell survaival. These data indicates that HSP47 may be a chaperone molecular for collagen type V and inhibit cell invasion by regulating expression of TIMP2.