Up-regulation and clinical significance of serine protease kallikrein 6 in colon cancer

Authors

  • Jong-Tae Kim PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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    • The first two authors contributed equally to this article.

  • Eun Young Song PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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  • Kyung-Sook Chung PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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  • Min Ah Kang MS,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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    • The first two authors contributed equally to this article.

  • Jae Wha Kim PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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  • Sang Jick Kim PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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  • Young Il Yeom PhD,

    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
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  • Joo Heon Kim MD, PhD,

    1. Department of Pathology, Eulji University School of Medicine, Daejeon, Republic of Korea
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  • Kyo Hyun Kim MD, PhD,

    1. Department of Preventive Medicine, Eulji University School of Medicine, Daejeon, Republic of Korea
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  • Hee Gu Lee PhD

    Corresponding author
    1. Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Republic of Korea
    • Medical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology, Yuseong, Daejeon 305-333, Republic of Korea

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    • Fax: (011) 82-42-860-4593


Abstract

BACKGROUND:

Kallikrein-related peptidase 6 (KLK6) encodes a trypsin-like serine protease that is up-regulated in several cancers, although the putative functions of KLK6 in cancer have not been elucidated. In the current study, overexpression of KLK6 was identified in colon cancer, and the possibility that KLK6 may be a suitable candidate as a tumor marker was examined.

METHODS:

Messenger RNA (mRNA) transcript levels and protein up-regulation of KLK6 in colon cancer tissues was examined using reverse transcriptase-polymerase chain reaction, immunohistochemistry, and clinicopathologic analyses. Cell proliferation, invasiveness, and antiapoptotic activity were determined in colon cancer cells that were transfected with small-interfering RNA (siRNA) of KLK6.

RESULTS:

KLK6 mRNA was up-regulated significantly in tumor tissues compared with nontumor regions. KLK6 protein was strongly expressed in adenocarcinomas but was not expressed in normal mucosa or in premalignant dysplastic lesions. Sera from patients with colon cancer revealed an increase in KLK6 secretion (0.25 μg/mL; P = .031) compared with noncancer cells (0.19 μg/mL). Clinicopathologic and immunohistochemical studies of 143 patients with colon cancer revealed a significant correlation between KLK6 expression and Dukes disease stage (P = .005). High KLK6 expression was associated significantly with shorter overall (P = .001) and recurrence-free survival (P = .001). The rates of proliferation and invasiveness were decreased by 50% in cells that were transfected with KLK6 siRNA. The overexpression of KLK6 led to decreased activity of the E-cadherin promoter.

CONCLUSIONS:

KLK6 was up-regulated significantly in tissues and sera from patients with colon cancer and was associated closely with a poor prognosis, suggesting that KLK6 may be used as a potential biomarker and a therapeutic target for colon cancer. Cancer 2011;. © 2010 American Cancer Society.

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