G9a inhibition by CM-272: Developing a novel anti-tumoral strategy for castration-resistant prostate cancer using 2D and 3D in vitro models
Filipa Moreira-Silva 1, Gonçalo Outeiro-Pinho 2, João Lobo 3, Rita Guimarães 4, Vítor M Gaspar 5, João F Mano 6, Xabier Agirre 7, António Pineda-Lucena 8, Felipe Prosper 9, Jesus M Paramio 10, Rui Henrique 11, Margareta P Correia 12, Carmen Jerónimo 13
Castration-resistant prostate cancer (CRPC) is an incurable form of prostate cancer (PCa), with DNMT1 and G9a being reported as overexpressed, rendering them highly attractive targets for precision medicine. CM-272 is a dual inhibitor of both methyltransferases' activity.
Herein, we assessed the response of different PCa cell lines to CM-272, in both 2D and 3D models, and explored the molecular mechanisms underlying CM-272 inhibitory effects. CRPC tissues displayed significantly higher DNMT1, G9a and H3K9me2 expression than localized PCa.
In vitro, CM-272 caused a significant decrease in PCa cell viability and proliferation alongside with increased apoptotic levels. We disclose that, under the evaluated dose, CM-272 led to G9a activity inhibition, while not significantly affecting DNMT1 activity. Upon G9a knockdown, DU145 and PC3 showed decreased cell viability. Remarkably, DU145 cells treated with CM-272 or with G9a knockdown displayed no differences in viability, suggesting a SET-dependent mechanism. Contrarily, PC3 cell viability impact was higher in G9a knockdown, compared with CM-272 treatment, suggesting an additional G9a function.
Moreover, DU145 cells overexpressing catalytically functional G9a disclosed higher resistance to CM-272 treatment, reinforcing that the drug mechanism of action is dependent on G9a catalytic function. Importantly, we successfully assembled spheroids from several prostate cell lines. Our results showed that CM-272 retained its anti-tumoral effects in 3D PCa models, leading to a clear reduction in cancer cell survival. We concluded that inhibition of G9a methyltransferase activity by CM-272 has anti-tumor effect in PCa cells, holding therapeutic potential against CRPC.
Keywords: CM-272; Castration-resistant prostate cancer; Epigenetics; G9a; Spheroids.CITA DEL ARTÍCULO Biomed Pharmacother. 2022 Jun;150:113031. doi: 10.1016/j.biopha.2022.113031. Epub 2022 Apr 25.