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Open Access Research article

Up-regulated expression of l-caldesmon associated with malignancy of colorectal cancer

Kyung-Hee Kim12, Seung-Gu Yeo3, Won Ki Kim1, Dae Yong Kim14, Hyun Yang Yeo1, Jun Pyu Hong1, Hee Jin Chang14, Ji Won Park14, Sun Young Kim4, Byung Chang Kim4 and Byong Chul Yoo1*

Author Affiliations

1 Colorectal Cancer Branch, Division of Translational and Clinical Research I, Research Institute, National Cancer Center, Goyang, 410-769, Republic of Korea

2 Laboratory of Cell Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, 110-744, Republic of Korea

3 Department of Radiation Oncology, Soonchunhyang University College of Medicine, Cheonan, 330-721, Republic of Korea

4 Center for Colorectal Cancer, Hospital, National Cancer Center, Goyang, 410-769, Republic of Korea

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BMC Cancer 2012, 12:601  doi:10.1186/1471-2407-12-601

Published: 17 December 2012

Abstract

Background

Caldesmon (CaD), a major actin-associated protein, is found in smooth muscle and non-muscle cells. Smooth muscle caldesmon, h-CaD, is a multifunctional protein, and non-muscle cell caldesmon, l-CaD, plays a role in cytoskeletal architecture and dynamics. h-CaD is thought to be an useful marker for smooth muscle tumors, but the role(s) of l-CaD has not been examined in tumors.

Methods

Primary colon cancer and liver metastasis tissues were obtained from colon cancer patients. Prior to chemoradiotherapy (CRT), normal and cancerous tissues were obtained from rectal cancer patients. Whole-tissue protein extracts were analyzed by 2-DE-based proteomics. Expression and phosphorylation level of main cellular signaling proteins were determined by western blot analysis. Cell proliferation after CaD siRNA transfection was monitored by MTT assay.

Results

The expression level of l-CaD was significantly increased in primary colon cancer and liver metastasis tissues compared to the level in the corresponding normal tissues. In cancerous tissues obtained from the patients showing poor response to CRT (Dworak grade 4), the expression of l-CaD was increased compared to that of good response group (Dworak grade 1). In line with, l-CaD positive human colon cancer cell lines were more resistant to 5-fluorouracil (5-FU) and radiation treatment compared to l-CaD negative cell lines. Artificial suppression of l-CaD increased susceptibility of colon cancer cells to 5-FU, and caused an increase of p21 and c-PARP, and a decrease of NF-kB and p-mTOR expression.

Conclusion

Up-regulated expression of l-CaD may have a role for increasing metastatic property and decreasing CRT susceptibility in colorectal cancer cells.