Zitha Redempta Isingizwe

Identification and Experimental Validation of Triosephosphate Isomerase 1 as a Functional Biomarker of SHetA2 Sensitivity in Ovarian Cancer

Background: Our objective was to identify and validate proteins that predict which patients with ovarian cancer will respond to SHetA2, an investigational drug in a phase 1 trial for patients with advanced or recurrent solid tumors (clinicaltrials.gov: NCT04928508). Methods: Cells were cultured from ascites from nine consented patients under an institutional review board-approved protocol. SHetA2 or olaparib sensitivities were determined using metabolic viability assays in ascites-derived cultures or ovarian cancer cell lines. Expression of four SHetA2 target proteins and sixteen proteins previously identified in an ovarian cancer mouse model were measured using microcapillary electrophoresis. Triosephosphate isomerase 1 (TPI1) was modulated by siRNA or lentivirus vector-mediated overexpression. Metabolites were measured using mass spectrometry. Results: TPI1 was elevated in SHetA2-sensitive compared to SHetA2-resistant ascites-derived cultures (two-way ANOVA q-value = 0.0003). The majority of (5/9) cultures were olaparib-resistant and SHetA2-sensitive. TPI1 was higher in olaparib-resistant cultures (two-way ANOVA q-value = 0.0003). Reduction in or overexpression of TPI1 reduced or increased SHetA2 potency, respectively, in two ovarian cancer cell lines (t-tests; p < 0.05). SHetA2 reduced the metabolites in glycolysis downstream of TPI1, the tricarboxylic acid cycle and oxidative pentose phosphate pathway. Conclusions: TPI1 is a candidate functional biomarker of SHetA2 sensitivity in ovarian cancer.

Targeting HSP70‐E7 Interaction With SHetA2: A Novel Therapeutic Strategy for Cervical Cancer

ABSTRACT Cervical cancer is predominantly driven by persistent infections with high‐risk human papillomavirus and the continuous activity of its E6 and E7 oncoproteins. This study explored the role of heat shock proteins 70 kDa (HSP70s) in enhancing the function of these oncoproteins and examined the impact of SHetA2, an investigational new drug, on this interaction. We found that HSP70 specifically binds to E7, but not E6, protein and that SHetA2 disrupts this binding. This disruption led to a significant reduction in E6 and E7 mRNA and E7 protein levels, while effects on E6 protein levels were minimal. SHetA2 treatment also resulted in altered levels of cell cycle regulatory proteins, reduced cell cycle progression, and decreased metabolic viability in cervical cancer cell lines and xenograft models. These findings support the potential of SHetA2 to impair cervical cancer progression by targeting HSP70/E7 interactions, highlighting its promise as a therapeutic strategy for treating cervical cancer.