Exploring the Molecular Players behind the Potentiation of Chemotherapy Effects by Durvalumab in Lung Adenocarcinoma Cell Lines

Abstract

Immune checkpoint inhibitors are increasingly used in combination with chemotherapy for the treatment of non-small cell lung cancer, yet the success of combination therapies is relatively limited. Thus, more detailed insight regarding the tumor molecular markers that may affect the responsiveness of patients to therapy is required. Here, we set out to explore the proteome of two lung adenocarcinoma cell lines (HCC-44 and A549) treated with cisplatin, pemetrexed, durvalumab, and the corresponding mixtures to establish the differences in post-treatment protein expression that can serve as markers of chemosensitivity or resistance. The mass spectrometry study showed that the addition of durvalumab to the treatment mixture resulted in cell line- and chemotherapeutic agent-dependent responses and confirmed the previously reported involvement of DNA repair machinery in the potentiation of the chemotherapy effect. Further validation using immunofluorescence also indicated that the potentiating effect of durvalumab in the case of cisplatin treatment was dependent on the tumor suppressor RB-1 in the PD-L1 weakly positive cells. In addition, we identified aldehyde dehydrogenase ALDH1A3 as the general putative resistance marker. Further studies in patient biopsy samples will be required to confirm the clinical significance of these findings.

Inhibition of epigenetic and cell cycle-related targets in glioblastoma cell lines reveals that onametostat reduces proliferation and viability in both normoxic and hypoxic conditions

“…The cells were incubated for 48 h at 37 °C in normoxic conditions. Subsequently, fixation, IF staining and DAPI staining of cells was carried out according to the previously published protocol 17 . The primary antibodies were used at the following dilutions: anti-pS3H10, 1:2000 (N = 6); anti-AurA, 1:500 (N = 3); anti-CCNA2, 1:120 (N = 3); anti-CENPF, 1:500 (N = 3); anti-NCL, 1:500 (N = 3); anti-NuMA, 1:300 (N = 6); anti-H4R3me1, 1:1000 (N = 4).…”

“…The analysis of the raw IF data was carried out according to the previously established protocol 17 . The total intensity of antibody signal in nucleus was plotted by pooling data for all nuclei identified from the identically treated cells in all the independent experiments (N = 4–6).…”