Localization of heparin cofactor II in injured human skin: a potential role in wound healing

Suggestions on leading an academic research laboratory group

This commentary is about running an academic research laboratory group, including some reflections, memories, and tips on effectively managing such a group of scientists focused on one’s research. The author’s academic career has spanned from 1982 to 2022, including postdoctoral research associate through the rank of professor with tenure. Currently, the author is in the final year of 3 years of phased retirement. One must be willing to work hard at running a research laboratory. Also, stay focused on funding the laboratory tasks and publishing one’s work. Recruit the best people possible with advice from the collective laboratory group. Laboratory group members felt more like they were a part of a collective family than simply employees; however, what works best for the researcher is what matters. Several other points to discuss will include managing university roles, recruiting laboratory personnel, getting recognition, dealing with intellectual property rights, and publishing work. In closing, there are many more positives than negatives to leading a research laboratory group. Finally, one cannot replace the unforgettable memories and the legacy of a research laboratory group.

Heparin co-factor II enhances cell motility and promotes metastasis in non-small cell lung cancer

Using the Serial Analysis of Gene Expression (SAGE) database from the Cancer Genome Anatomy Project, we identified heparin co-factor II (HCII), which is over-expressed in non-small cell lung cancer (NSCLC). Here, we investigated the clinical significance of HCII and provided molecular evidence to support the suggestion that HCII could enhance cancer metastasis in NSCLC. We found that high HCII expression in tumour tissue was associated with increased cancer recurrence and shorter overall survival times in 75 clinically operable NSCLC patients. High pretreatment plasma concentration of HCII was associated with reduced overall survival in 57 consecutive NSCLC patients. We over-expressed and knocked down HCII expression in lung cancer cell lines and confirmed that HCII could promote cell motility, invasion ability and filopodium dynamics in NSCLC cells in vitro and increased metastatic colonization in an in vivo mouse model. Exogenous treatment of HCII promoted cancer cell migration, and this promigratory effect of HCII was independent of thrombin. We further showed that HCII could up-regulate cancer cell migration through the activation of PI3K, which acts upstream of Rac1 and Cdc42, and this effect could be blocked by heparin. We suggest that HCII is a novel metastasis enhancer and may be used as a prognostic predictor for heparin treatment in NSCLC.

Regulation of Thrombin Activity—Pharmacologic and Structural Aspects

Thrombin is an essential serine protease for survival. Since the discovery of heparin in the early twentieth century, significant advances have been made in the understanding of thrombin structure and function in coagulation system. Endogenous anticoagulant proteins in blood tightly regulate thrombin generation, but additional anticoagulant agents may be necessary to suppress excessive thrombin formation or defective anticoagulant proteins. Despite the availability of an array of anticoagulant agents based on chemical and biological engineering technologies, anticoagulation therapy remains a challenge for clinicians in terms of balancing bleeding and thrombosis. The aim of this article is to review endogenous serine protease inhibitors and novel antithrombotic agents in relation to pharmacologic regulation of thrombin.

Protein C inhibitor (plasminogen activator inhibitor-3) expression in the CWR22 prostate cancer xenograft

The serine protease inhibitor (serpin) protein C inhibitor (PCI) has been found in the prostate and possibly is a marker to distinguish normal prostate, benign prostatic hyperplasia, and prostate cancer. In this study, we assessed PCI expression in normal, hyperplastic, and malignant prostatic tissues, prostate cancer cell lines, and the CWR22 prostate cancer xenograft model that allowed us to study PCI expression and its regulation in response to androgens. By Northern blot, immunohistochemistry, and in situ hybridization, we found that PCI was expressed in both benign and malignant prostate tissues. Protein C inhibitor was expressed in both androgen-independent (PC-3) and androgen-dependent (LNCaP) prostate cancer cell lines. Furthermore, PCI was detected in all CWR22 tumor samples (androgen dependent, 6 days post-castration, 12 days post-castration followed by 72 h of testosterone treatment, and recurrent CWR22 tumor), although expression of the mature forms of both prostate-specific antigen (PSA) and its homolog, kallikrein 2 (hK2), was clearly androgen-dependent. These results suggest that PCI expression is not regulated by androgens and that PCI is unlikely to be a tumor suppressor gene, but also that PCI may be involved in regulating key serine proteases involved in metastatic prostate disease.

Molecular Mapping of the Thrombin-Heparin Cofactor II Complex

We used 55 Ala-scanned recombinant thrombin molecules to define residues important for inhibition by the serine protease inhibitor (serpin) heparin cofactor II (HCII) in the absence and presence of glycosaminoglycans. We verified the importance of numerous basic residues in anion-binding exosite-1 (exosite-1) and found 4 additional residues, Gln24, Lys65, His66, and Tyr71 (using the thrombin numbering system), that were resistant to HCII inhibition with and without glycosaminoglycans. Inhibition rate constants for these exosite-1 (Q24A, K65A, H66A, Y71A) thrombin mutants (0.02-0.38 x 10(8) m(-1) min(-1) for HCII-heparin when compared with 2.36 x 10(8) m(-1) min(-1) with wild-type thrombin and 0.03-0.53 x 10(8) m(-1) min(-1) for HCII-dermatan sulfate when compared with 5.23 x 10(8) m(-1) min(-1) with wild-type thrombin) confirmed that the structural integrity of thrombin exosite-1 is critical for optimal HCII-thrombin interactions in the presence of glycosaminoglycans. However, our results are also consistent for HCII-glycosaminoglycan-thrombin ternary complex formation. Ten residues surrounding the active site of thrombin were implicated in HCII interactions. Four mutants (Asp51, Lys52, Lys145/Thr147/Trp148, Asp234) showed normal increased rates of inhibition by HCII-glycosaminoglycans, whereas four mutants (Trp50, Glu202, Glu229, Arg233) remained resistant to inhibition by HCII with glycosaminoglycans. Using 11 exosite-2 thrombin mutants with 20 different mutated residues, we saw no major perturbations of HCII-glycosaminoglycan inhibition reactions. Collectively, our results support a "double bridge" mechanism for HCII inhibition of thrombin in the presence of glycosaminoglycans, which relies in part on ternary complex formation but is primarily dominated by an allosteric process involving contact of the "hirudin-like" domain of HCII with thrombin exosite-1.