168P - HUWE1 inhibition has tumor suppressive effect in triple-negative breast cancer cell lines by modulating glycolytic and immune modulatory markers

Background

The E3 ligase HUWE1 is a key regulator of the DNA damage response, transcription, autophagy, apoptosis and metabolism in a variety of cancers. Due to its pivotal role in conferring substrate specificity, HUWE1 has attracted enormous attention as a promising anticancer drug target. In this study, we have studied the role of HUWE1 in triple-negative breast cancer (TNBC) cell lines and evaluated its role on aerobic glycolysis which is upregulated in cancer cells and immune modulatory markers for their roles in immunotherapy. TNBC subtype neither express hormone receptors nor Her2/neu. TNBC are highly aggressive, with poor prognosis and no well-defined treatment regimen. Therefore, considering HUWE1 as an oncogene its role has been explored on glucose metabolism and immune modulation in TNBC cell lines.

Methods

Two TNBC cell lines i.e. MDA-MB-231 and MDA-MB-468 were used in the present study. These cell lines were treated with HUWE1 inhibitor: BI8622 for 24 h and the effect of inhibition was seen on its substrate (c-myc), aerobic glycolytic (HK-2, GLUT-1) and immune checkpoint markers (PDL-1, CD-47) using western blotting approach. Wound healing assays and clonogenic assays were also performed in BI8622 treated cells to check the effects of HUWE1 inhibition on migration and colony forming ability of TNBC cells in both the cell lines.

Results

As expected, there was a decrease in the protein expression levels of c-myc after the HUWE1 inhibition. Furthermore, there was decrease in protein expression of glycolytic markers i.e. HK-2 and GLUT-1 as well as immuno modulatory markers i.e. PDL-1 and CD-47. Additionally, the HUWE1 inhibition in TNBC cells was positively associated with the inhibition of migration and clonogenic potential.

Conclusions

In this study for the first time, we have demonstrated that HUWE1 acts as a tumor suppressor in TNBC by regulating the glucose metabolism and immune checkpoint inhibitors. HUWE1 inhibition could functionally suppress TNBC development possibly by regulating aerobic glycolysis and immune checkpoints through c-myc.

Clinical trial identification

Editorial acknowledgement

ICMR- Indian Council of Medical Research, New Delhi, India

Legal entity responsible for the study

Shruti Kahol, Sandeep Mathur.

Funding

Indian Council of Medical Research, ICMR, New Delhi.

Disclosure

All authors have declared no conflicts of interest.