HtrA3 in cancer and ageing

Summary

We have discovered and cloned a new gene, HtrA3, in the mouse and human, and identified that it is a previously unrecognised factor important for placental development and function. We have also established that HtrA3 is a potential tumor suppressor. We are characterising the biochemical properties of HtrA3 and investigating its role in cancer progression.

Description

HtrA3 is new member of the mammalian HtrA family. The first member of HtrA (high temperature requirement factor A) was identified in E.coli as a heat shock protein required for high temperature tolerance. Subsequently, mammalian HtrA3 proteins (4 members to date) have been identified with a range of cellular functions such as in apoptosis and cancer.

We discovered and cloned HtrA3 both in the mouse and human, and established that it is closely associated with placental development in both species. Our studies have also established that HtrA3 is down-regulated in a number of cancers including uterine and ovarian cancers.

Because HtrA3 is a newly identified factor, its biochemical functions are largely unknown. We are currently characterising the biochemical properties of HtrA3 using a range of biochemistry and molecular biology techniques, including protein expression, mutagenesis, protein purification, and GST-pull-down assays, to search for binding proteins and substrates.We are also investigating the physiological roles of HtrA3 in cancer invasion and progression using cell and mouse models. We are particularly interested in the interrelationship between HtrA3, cancer and ageing.

Funding

National Health and Medical Research Council

Outcomes

Our studies indicate that HtrA3 is auto-cleaved for its proteolytic function. It may target cytoskeletal and extra-cellular matrix proteins. Its role in cancer is associated with ageing.

Selected Publications

Singh H, Makino S, Endo Y, Li Y, Stephens AN and Nie G (2012) Application of the wheat-germ cell-free translation system to produce high temperature requirement A3 (HtrA3) proteases. BioTechniques 52: 23-28

Li Y, Puryer M, Lin E, Hale K, Salamonsen LA, Manuelpillai U, Tong S, Chan W, Wallace EM and Nie G (2011) Placental HtrA3 is regulated by oxygen tension and serum levels are altered during early pregnancy in women destined to develop preeclampsia. J Clin Endocrinol Metab 96: 403-411

Singh H, Endo Y, Nie G. (2011) Decidual HtrA3 negatively regulates trophoblast invasion during human placentation. Human Reprod 26: 748-757

Singh H, Makino S-I, Endo Y and Nie G (2010) Inhibition of HTRA3 stimulates trophoblast invasion during human placental development. Placenta 31: 1085-1092

Bowden MA, Drummond AE, Salamonsen LA, Findlay JK, and Nie G (2009) Evolutionary conservation of mammalian HtrA3 and its developmental regulation in the rat ovary. J Exp Zool Part B 312: 701-713

Nie G (2008) The critical role of a novel protease in normal and abnormal placentation. Biol Reprod 78: p275

Bowden MA, Li Y, Findlay JK, Salamonsen LA and Nie G (2008) HtrA3 expression in non-pregnant rhesus monkey ovary, endometrium and at the maternal-fetal interface during early pregnancy. Reprod Biol Endocrinol 6: 1-11

Bowden MA, Di Nezza-Cossens LA, Jobling T, Salamonsen LA and Nie G (2006) Serine proteases HtrA1 and HtrA3 are down-regulated with increasing grades of human endometrial cancer. Gynecol Oncol 103: 253-260

Nie G, Li Y, He H, Findlay JK and Salamonsen LA (2006) Serine protease HtrA3 possessing an IGF binding domain is specifically expressed in the maternal-fetal interface during placentation in the mouse. Placenta 27: 491-501

Nie G, Li Y, Hale K, Okada H, Manuelpillai U, Wallace EM and Salamonsen LA (2006) Serine peptidase HtrA3 is closely associated with human placental development and elevated in pregnancy serum. Biol Reprod 74: 366-374

Nie G, Hampton A, Li Y, Findlay JK, Salamonsen LA (2003) Identification and cloning of two isoforms of human HtrA3, characterisation of its genomic structure and comparison of its tissue distribution with HtrA1 and HtrA2. Biochem J 371: 39-48

Nie G, Li Y, Minoura H, Batten L, Ooi GT, Findlay JK and Salamonsen LA (2003) A novel serine protease of the mammalian HtrA family is dramatically up-regulated in mouse uterus coinciding with placentation. Mol Hum Reprod 9: 279-290

PHI Research Team