HOXA9 is Underexpressed in Cervical Cancer Cells and its Restoration Decreases Proliferation, Migration and Expression of Epithelial-to-Mesenchymal Transition Genes.

Liliana Alvarado-Ruiz,Luis Alberto Torres-Reyes,Maria Guadalupe Martinez-Silva,Luis Felipe Jave-Suarez,Alejandro Bravo-Cuellar,Pablo Ortiz-Lazareno,Adriana Aguilar-Lemarroy,Patricia Pina-Sanchez

doi:10.7314/apjcp.2016.17.3.1037

Liliana Alvarado-Ruiz, Luis Alberto Torres-Reyes + Show 6 more

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https://doi.org/10.7314/apjcp.2016.17.3.1037

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Abstract

HOX transcription factors are evolutionarily conserved in many different species and are involved in important cellular processes such as morphogenesis, differentiation, and proliferation. They have also recently been implicated in carcinogenesis, but their precise role in cancer, especially in cervical cancer (CC), remains unclear. In this work, using microarray assays followed by the quantitative polymerase chain reaction (qPCR), we found that the expression of 25 HOX genes was downregulated in CC derived cell lines compared with nontumorigenic keratinocytes. In particular, the expression of HOXA9 was observed as down-modulated in CCderived cell lines. The expression of HOXA9 has not been previously reported in CC, or in normal keratinocytes of the cervix. We found that normal CC from women without cervical lesions express HOXA9; in contrast, CC cell lines and samples of biopsies from women with CC showed significantly diminished HOXA9 expression. Furthermore, we found that methylation at the first exon of HOXA9 could play an important role in modulating the expression of this gene. Exogenous restoration of HOXA9 expression in CC cell lines decreased cell proliferation and migration, and induced an epithelial-like phenotype. Interestingly, the silencing of human papilloma virus (HPV) E6 and E7 oncogenes induced expression of HOXA9. In conclusion, controlling HOXA9 expression appears to be a necessary step during CC development. Further studies are needed to delineate the role of HOXA9 during malignant progression and to afford more insights into the relationship between downmodulation of HOXA9 and viral HPV oncoprotein expression during cercical cancer development.

Highlights

Cervical Cancer (CC) is the fourth most common cancer in women, and the seventh overall, with an estimated 528,000 new cases in 2012 (Ferlay et al, 2015)
In this work, using microarray assays followed by the quantitative polymerase chain reaction, we found that the expression of 25 HOX genes was downregulated in CC derived cell lines compared with nontumorigenic keratinocytes
It was observed that of the 39 human HOX genes, the expression of 26 members remain unchanged in both cell lines; HOXA3, HOXA9, HOXB4, HOXC12, HOXC13, HOXD10, and HOXD11 were observed with lower expression in HeLa cells compared with HaCaT, and for HOXA11, HOXB3, HOXB5, HOXB6, HOXB9, and HOXB13, increased expression was observed (Figure 1a)

Summary

Introduction

Cervical Cancer (CC) is the fourth most common cancer in women, and the seventh overall, with an estimated 528,000 new cases in 2012 (Ferlay et al, 2015). Development of this disease is closely associated with human papilloma virus (HPV) infection (Bosch and Munoz, 2002); it is estimated that only 0.03% of women who become infected with HPV proceed to develop CC (Sasagawa et al, 2012). Alterations in developmental signaling pathways or transcription factors that regulate the ontogeny, such HOX genes, have recently been proposed as alternative secondary modifications that could lead to malignant transformation (Karamboulas and Ailles, 2013). HOX genes play an important role in the delicate balance between cell proliferation and differentiation that is essential for normal fetal development during embryogenesis; the abnormal

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