Tumor-resident Lactobacillus iners confer chemoradiation resistance

To test whether Lactobacillus iners (L. iners) from cervical cancers could directly cause radiation resistance independent of an immune effect, we cultured, isolated and speciated L. iners strains from cervical tumors using anaerobic culture techniques, then filtered bacterial supernatant to produce cell-free supernatant (CFS). To explore how L. iners CFS might alter cancer cell sensitivity to irradiation (IR) treatment, we performed RNA sequencing for cervical cancer-derived primary cells pre-treated with CFS from the speciated L. iners vs. controls.We generated a cervical cancer patient-derived organoid line (PDO, B1188) which develops a dense 3D morphology, had response to both irradiation (IR) and cisplatin treatments. A line of primary cells was generated after several passages of the PDOs (B1188 primary cells). B1188 primary cells were then incubated for two weeks with 20% CFS harvested from two cancer-derived L. iners strains (CC-L. iners), one commercial non-cancer-associated L. iners strains (NC-L. iners), or Control (CTRL, 20% NYC Broth), prior to treatment with ionizing radiation (IR). We collected the IR treated/non-treated cells for bulk RNAseq.