SMU Medical Journal

Arumugam Jayakumar ¹, Hua-Kang Wu ¹, Katrina Briggs ¹, Thomas Shellenberger ¹, Ya'an Kang ¹, Kenji Mitsudo ¹, Mary Wang ¹, Mitchell J. Frederick ¹, Ying Henderson ¹, Paula R. Holton ¹, Venugopal Radjendirane ², Karthik Jayakumar ³, Dieter Brömme ⁴

Affiliations
1 Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, US
2 Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, US
3 The American University of Antigua, Mount Sinai School of Medicine, New York, New York 10029-6574, US
4 Department of Human Genetics Mount Sinai School of Medicine, New York, New York 10029-6574, US

Abstract

Cathepsin K is a protease with high collagenolytic and elastinolytic activity. A full-length cDNA clone of human cathepsin K was used to construct an expression system in insect cells. The recombinant protein had a C-terminal tag of six histidine residues, which allowed purification of this protein by a one-step Co²⁺-Sepharose affinity chromatography. Minimal amounts of pro-cathepsin K were secreted into the medium but most of the cathepsin K was present within infected cells. Very little processing of pro-enzyme to mature form occurred in High Five cells. Spontaneous in vitro activation of pro-cathepsin K to mature-cathepsin K occurred at pH 4.0. The ∼29 kDa mature-cathepsin K efficiently hydrolyzed the fluorogenic peptide substrate and r-headpin, a serine protease inhibitor down-regulated in head and neck cancer cell lines and tumor tissues, potently inhibited the r-catK activity in vitro. Taking cathepsin K as an example, we present a strategy, which should facilitate the expression of perhaps other cathepsins or proteases in general in insect cells.

Keywords

Cathepsink, Sf9, Metal Affinity Chromatography, HNSCC, Headpin.

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Thomas Shellenberger ¹, Mitchell J. Frederick ¹, Ying Henderson ¹, Yaan Kang ¹, Karthik Jayakumar ², Vikram Vijayarajan ³, Gary L. Clayman ¹, Rajendra Prasad ⁴, Arumugam Jayakumar ¹

Affiliations
1 Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, US
2 Department of Medicine, Section of Emergency Medicine, Baylor College of Medicine, Houston, TX 77030, IN
3 The American University of Antigua, College of Medicine, Antigua and Barbuda, AG
4 Amity Institute of Integrative Sciences and Health, Amity University of Haryana, Gurgaon-122413, IN

Abstract

Perineural invasion (PNI) is a unique route of tumor metastasis that is strongly associated with poor prognosis in several solid malignancies including head and neck squamous cell carcinoma (HNSCC). Recently, we investigated the pattern of Lympho-Epithelial Kazal-Type-Inhibitor (LEKTI) expression in primary tumor specimens of patients with SCC of the oral tongue in correlation with PNI and showed a strong association between absence of LEKTI expression and occurrence of PNI. Based upon the negative correlation of LEKTI expression with PNI in SCC of the tongue, we hypothesized that the same correlation may exist in SCC of the skin. Here, we selected a total of 11 cases with PNI and 15 cases without PNI. Our analyses showed a strong correlation between LEKTI expression and PNI in SCC of the skin and suggested that LEKTI might also be one of the critical molecules involved in the regulation of PNI of neuroendocrine cancers including of HNSCC.

Keywords

LEKTI, Perineural Invasion, HNSCC.

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