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Selective cleavage of human sex hormone-binding globulin by kallikrein-related peptidases and effects on androgen action in LNCaP prostate cancer cells.
Endocrinology 2012; 153(7):3179-89E

Abstract

Stimulation of the androgen receptor via bioavailable androgens, including testosterone and testosterone metabolites, is a key driver of prostate development and the early stages of prostate cancer. Androgens are hydrophobic and as such require carrier proteins, including sex hormone-binding globulin (SHBG), to enable efficient distribution from sites of biosynthesis to target tissues. The similarly hydrophobic corticosteroids also require a carrier protein whose affinity for steroid is modulated by proteolysis. However, proteolytic mechanisms regulating the SHBG/androgen complex have not been reported. Here, we show that the cancer-associated serine proteases, kallikrein-related peptidase (KLK)4 and KLK14, bind strongly to SHBG in glutathione S-transferase interaction analyses. Further, we demonstrate that active KLK4 and KLK14 cleave human SHBG at unique sites and in an androgen-dependent manner. KLK4 separated androgen-free SHBG into its two laminin G-like (LG) domains that were subsequently proteolytically stable even after prolonged digestion, whereas a catalytically equivalent amount of KLK14 reduced SHBG to small peptide fragments over the same period. Conversely, proteolysis of 5α-dihydrotestosterone (DHT)-bound SHBG was similar for both KLKs and left the steroid binding LG4 domain intact. Characterization of this proteolysis fragment by [(3)H]-labeled DHT binding assays revealed that it retained identical affinity for androgen compared with full-length SHBG (dissociation constant = 1.92 nM). Consistent with this, both full-length SHBG and SHBG-LG4 significantly increased DHT-mediated transcriptional activity of the androgen receptor compared with DHT delivered without carrier protein. Collectively, these data provide the first evidence that SHBG is a target for proteolysis and demonstrate that a stable fragment derived from proteolysis of steroid-bound SHBG retains binding function in vitro.

Authors+Show Affiliations

Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland 4059, Australia.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22547569

Citation

Sanchez, Washington Y., et al. "Selective Cleavage of Human Sex Hormone-binding Globulin By Kallikrein-related Peptidases and Effects On Androgen Action in LNCaP Prostate Cancer Cells." Endocrinology, vol. 153, no. 7, 2012, pp. 3179-89.
Sanchez WY, de Veer SJ, Swedberg JE, et al. Selective cleavage of human sex hormone-binding globulin by kallikrein-related peptidases and effects on androgen action in LNCaP prostate cancer cells. Endocrinology. 2012;153(7):3179-89.
Sanchez, W. Y., de Veer, S. J., Swedberg, J. E., Hong, E. J., Reid, J. C., Walsh, T. P., ... Harris, J. M. (2012). Selective cleavage of human sex hormone-binding globulin by kallikrein-related peptidases and effects on androgen action in LNCaP prostate cancer cells. Endocrinology, 153(7), pp. 3179-89. doi:10.1210/en.2012-1011.
Sanchez WY, et al. Selective Cleavage of Human Sex Hormone-binding Globulin By Kallikrein-related Peptidases and Effects On Androgen Action in LNCaP Prostate Cancer Cells. Endocrinology. 2012;153(7):3179-89. PubMed PMID: 22547569.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Selective cleavage of human sex hormone-binding globulin by kallikrein-related peptidases and effects on androgen action in LNCaP prostate cancer cells. AU - Sanchez,Washington Y, AU - de Veer,Simon J, AU - Swedberg,Joakim E, AU - Hong,Eui-Ju, AU - Reid,Janet C, AU - Walsh,Terry P, AU - Hooper,John D, AU - Hammond,Geoffrey L, AU - Clements,Judith A, AU - Harris,Jonathan M, Y1 - 2012/04/30/ PY - 2012/5/2/entrez PY - 2012/5/2/pubmed PY - 2012/9/21/medline SP - 3179 EP - 89 JF - Endocrinology JO - Endocrinology VL - 153 IS - 7 N2 - Stimulation of the androgen receptor via bioavailable androgens, including testosterone and testosterone metabolites, is a key driver of prostate development and the early stages of prostate cancer. Androgens are hydrophobic and as such require carrier proteins, including sex hormone-binding globulin (SHBG), to enable efficient distribution from sites of biosynthesis to target tissues. The similarly hydrophobic corticosteroids also require a carrier protein whose affinity for steroid is modulated by proteolysis. However, proteolytic mechanisms regulating the SHBG/androgen complex have not been reported. Here, we show that the cancer-associated serine proteases, kallikrein-related peptidase (KLK)4 and KLK14, bind strongly to SHBG in glutathione S-transferase interaction analyses. Further, we demonstrate that active KLK4 and KLK14 cleave human SHBG at unique sites and in an androgen-dependent manner. KLK4 separated androgen-free SHBG into its two laminin G-like (LG) domains that were subsequently proteolytically stable even after prolonged digestion, whereas a catalytically equivalent amount of KLK14 reduced SHBG to small peptide fragments over the same period. Conversely, proteolysis of 5α-dihydrotestosterone (DHT)-bound SHBG was similar for both KLKs and left the steroid binding LG4 domain intact. Characterization of this proteolysis fragment by [(3)H]-labeled DHT binding assays revealed that it retained identical affinity for androgen compared with full-length SHBG (dissociation constant = 1.92 nM). Consistent with this, both full-length SHBG and SHBG-LG4 significantly increased DHT-mediated transcriptional activity of the androgen receptor compared with DHT delivered without carrier protein. Collectively, these data provide the first evidence that SHBG is a target for proteolysis and demonstrate that a stable fragment derived from proteolysis of steroid-bound SHBG retains binding function in vitro. SN - 1945-7170 UR - https://www.unboundmedicine.com/medline/citation/22547569/Selective_cleavage_of_human_sex_hormone_binding_globulin_by_kallikrein_related_peptidases_and_effects_on_androgen_action_in_LNCaP_prostate_cancer_cells_ L2 - https://academic.oup.com/endo/article-lookup/doi/10.1210/en.2012-1011 DB - PRIME DP - Unbound Medicine ER -