Objectives
Although uterine cancer is the fourth most common cause for cancer death in
women worldwide, the molecular underpinnings of tumor progression remain poorly
understood. The High Mobility Group A1 (HMGA1) gene is overexpressed in
aggressive cancers and high levels portend adverse outcomes in diverse tumors. We
previously reported that Hmga1 transgenic mice develop uterine tumors
with complete penetrance. Because HMGA1 drives tumor progression by inducing
matrix metalloproteinase (MMP) and other genes
involved in invasion, we explored the HMGA1-MMP-2 pathway in uterine
cancer.
Methods
To investigate MMP-2 in uterine tumors driven by HMGA1, we used a genetic
approach with mouse models. Next, we assessed HMGA1 and
MMP-2 expression in primary human uterine tumors, including low-grade
carcinomas (endometrial endometrioid) and more aggressive tumors (endometrial serous
carcinomas, uterine carcinosarcomas/malignant mesodermal mixed tumors).
Results
Here, we report for the first time that uterine tumor growth is impaired in
Hmga1a transgenic mice crossed on to an Mmp-2
deficient background. In human tumors, we discovered that HMGA1 is
highest in aggressive carcinosarcomas and serous carcinomas, with lower levels in the
more indolent endometrioid carcinomas. Moreover, HMGA1 and
MMP-2 were positively correlated, but only in a subset of
carcinosarcomas. HMGA1 also occupies the MMP-2 promoter in human
carcinosarcoma cells.
Conclusions
Together, our studies define a novel HMGA1-MMP-2 pathway involved in a subset
of human carcinosarcomas and tumor progression in murine models. Our work also suggests
that targeting HMGA1 could be effective adjuvant therapy for more aggressive uterine
cancers and provides compelling data for further preclinical studies.