154P - Investigating the potential of estrogen-related receptor gamma (ERR?) in colorectal cancer and examining the therapeutic implications of DN200434 (ERR? inverse agonist) & MK2206 (Akt inhibitor)

Background

Colorectal cancer (CRC) represents a significant public health challenge globally, hence posing difficulties in treatment identification. Our study aimed to explore the role of ERRγ, which is a member of the NR3B nuclear receptor subfamily, in the progression of CRC. We assessed ERRγ expression in CRC to gauge its therapeutic potential and examined the anti-tumor impact of combining DN200434 with MK2206 in vitro and in vivo.

Methods

Colorectal cancer and adjacent healthy tissues were analyzed using IHC staining to evaluate ERRγ expression. The IC₅₀ values of DN200434 and MK2206 in CRC cells (SW-480, HT-29, and HCT-116) were determined via CCK-assay. Single and combination drug treatments were administered to assess their inhibitory effects, apoptosis induction, and cell cycle alterations. Western blot analysis validated the expression of various pathway markers. Crystal violet staining was performed to assess colony formation efficiency in treated cells. HCT-116 tumor bearing xenograft were established to confirm the anti-tumor efficacy of the drug combination.

Results

We noted an upregulation of ERRγ expression in the majority (75%) of CRC tissue samples compared to normal tissues. Additionally, the IC₅₀ values for DN200434 and MK2206 were found to be 35-40 μM and 15-20 μM respectively in CRC cells at 24 hours. Combining (DN200434 + MK2206) led to a synergistic increase in cell cytotoxicity up to 70-75%, compared to DN200434 (5-15%) and MK2206 (10-20%) alone. Moreover, combination treatment resulted in a significant reduction (70-80%) in colony-forming ability. Flow cytometry demonstrated notable apoptosis and G0/G1 cell cycle arrest. Similarly, western blot analysis showed increased levels of cleaved caspase-3 and cleaved-PARP indicating substantial apoptosis in combination-treated cells. Tumor development efficiency dropped to 30% in a mouse model, with an accompanying increase in lifespan.

Conclusions

Our findings highlight ERRγ's oncogenic role and can be proposed as a prognostic marker for CRC. The combination therapy of DN200434 and MK2206 provides a new way to advance to clinical trials for CRC management.

Legal entity responsible for the study

The authors.

Funding

Department of Health Research, Govt. of India.

Disclosure

All authors have declared no conflicts of interest.