The membrane-anchored serine protease, TMPRSS2, activates PAR-2 in prostate cancer cells

Abstract

TMPRSS2 is a type II transmembrane-bound serine protease that has gained interest owing to its highly localized expression in the prostate and its overexpression in neoplastic prostate epithelium. Once activated, the serine protease domain of TMPRSS2 is released from the cell surface into the extracellular space. PAR (protease-activated receptor)-2 belongs to a family of G-protein-coupled receptors (PAR-1-4) that are activated by specific serine proteases, which are expressed in many normal and malignant cell types. Previous in vitro studies on prostate cancer cells suggest a role for PAR-2 in prostate cancer metastasis. A polyclonal anti-human TMPRSS2 antibody was generated against the TMPRSS2 serine protease domain. The antibody showed specific reactivity with recombinant expressed TMPRSS2, and so was used to extract and purify the cleaved active TMPRSS2 protease from prostate cancer cells. Reverse transcriptase PCR and Western blot analysis were used to show the expression of both TMPRSS2 and PAR-2 in the androgen-dependent LNCaP prostate cancer cell line. Treatment of LNCaP cells with the cellular immunopurified TMPRSS2 protease induced a transient increase in intracellular calcium, which is indicative of G-protein-coupled-receptor activation. This calcium mobilization was inhibited by cellular pre-treatment with a specific PAR-2 antagonist, but not with a PAR-1 antagonist; inhibition of the protease activity also failed to mobilize calcium, suggesting that TMPRSS2 is capable of cleaving and thereby activating the PAR-2 receptor. The calcium mobilization was also inhibited by cellular pre-treatment with suramin or 2-APB (2-aminoethoxydiphenyl borate), indicating that a G-protein pathway is involved and that subsequent calcium release is mainly from intracellular stores. The present study describes how TMPRSS2 may contribute to prostate tumour metastasis via the activation of PAR-2.

The androgen receptor and prostate cancer: A role for sexual selection and sexual conflict?

“…In sum, these results are consistent with the hypothesis that KLK2 and PSA are positively selected in the context of sexually antagonistic coevolution, with the functional roles of the genes being of general importance to both the risk and somatic evolution of cancer. Transmembrane protease serine 2 has been identified as an important gene in the development of prostate cancer, with overexpression in neoplastic prostate epithelium [70]. The serine protease domain of TMPRSS2 is released into the extracellular fluid, and interacts there with a G-coupled receptor (PAR-2), which contributes to tumor metastasis.…”

In vitro characterization of TMPRSS2 inhibition in IPEC-J2 cells

“…By use of the PAR-2 antagonist Phe-Ser-Leu-Leu-Arg-Tyr-NH 2 it was found that matriptase and TMPRSS2 can activate PAR2, which suggests an additional link between a membrane-anchored serine protease and prostate tumor metastasis. However, further studies should be conducted if excessive amount of TMPRSS2 in intracellular space may play a functional role in prostate tumorigenesis in addition to cell surface protease activity 9,13,19 .…”

Neutrophil Elastase Activates Protease-activated Receptor-2 (PAR2) and Transient Receptor Potential Vanilloid 4 (TRPV4) to Cause Inflammation and Pain

“…In particular, given the widespread distribution of PAR 2 and the restricted expression of trypsin I/II to the pancreas, where activity is tightly controlled by endogenous inhibitors, the proteases that activate PAR 2 in tissues other than the pancreas and intestine remain to be identified. Other proteases that can cleave PAR 2 at Arg 36 2Ser 37 include trypsin IV (mesotrypsin) (17,18), tryptase (19,20), coagulation factors VIIa and Xa (21), acrosin (22), granzyme A (23), membrane-type serine protease 1 or matriptase (24), TMPRSS2 (25), and kallikrein 2, 4, 5, 6, and 14 (26 -29). These proteases would be expected to trigger the same canonical signaling events as trypsin I/II, leading to similar physiological outcomes.…”