Abstract A031: Combination of hedgehog targeting and autophagy inhibitor potentiate cytotoxicity in 3D spheroids of cervical cancer: A promising therapeutic strategy in metastatic disease

Abstract

Cervical cancer is the second most common malignancy in women and a major cause of morbidity and mortality worldwide. Statistics show that present biologic therapy has had little impact on survival in recurrent and metastatic disease. Consequently, there is an urgent need to explore the best treatment options for advanced cervical cancer. Hedgehog (Hh) signaling pathway has been shown to play an important role in metastasis, recurrence and drug resistance of cervical cancer. Therefore, inhibition of hedgehog signaling pathway is emerging as a new strategy for the treatment of advanced cervical cancer. Reports from various solid tumors show that efficacy of targeted therapy can be compromised due to the cytoprotective effect of autophagy upregulation in cancer cells. Therefore, the present study was designed to elucidate the effects of targeting Hh pathway on autophagic flux in cervical cancer spheroids (cervicospheroids). We developed 3D cervicospheroids as an in vitro model to study the Hh signaling and role of autophagy in cervical cancer. Characterisation of the cervicospheroids showed high expression of stemness genes like oct4, sox2 , nanog and CD 133 as well as epithelial to mesenchymal trasition genes like vimentin, snail and twist indicating that spheroids were enriched in cancer stem cell population. Acridine orange staining of 3D spheroids showed that autophagy was also enhanced in the cervicospheroids compared to monolayer culture. We observed a significant positive correlation between the expression of hedgehog mediator, Gli1 and autophagy protein, LC31 in immunohistochemistry data of archival sections of 45 patients of advanced cervical cancer. A higher autophagy flux, as indicated by presence of larger number autophagic vesicle compared to normal cervix, was also observed in these sections. These results further validated our in vitro observations in the 3D model of cervicospheres. MTT data, showed that autophagy help to evade the cytotoxicity of the chemotherapeutic drug, cisplatin in the cervicospheres. We further found an aberrantly activated Hh pathway in the cervicospheroids and observed that the effect of cisplatin and Hh inhibitor, GANT61 was potentiated when the autophagy inhibitor , chloroquine, was added to the 3D spheroid culture. These results led us to conclude that that 3-D spheroid grown in nonadherent conditions can be used as surrogate model to study molecular pathways involved in metastasis. Based on our present findings, we suggest a combinatorial approach targeting both cytoprotective autophagy and Hh pathway as a new therapeutic approach for targeting cancer stem cell population in cervical cancer . Citation Format: Shalmoli Bhattacharyya, Renaissa De, Radhika Srinivasan. Combination of hedgehog targeting and autophagy inhibitor potentiate cytotoxicity in 3D spheroids of cervical cancer: A promising therapeutic strategy in metastatic disease [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr A031.