Impact of the availability of active cytotoxic agents on the survival of patients with advanced gastric cancer

Curcumol Enhances the Sensitivity of Gastric Cancer to Cisplatin Resistance by Inducing Ferroptosis Through the P62/KEAP1/NRF2 Pathway

Background: Chemoresistance represented one of the challenges in the treatment of advanced gastric cancer (GC). Curcumol (CUR) was found to have a certain sensitizing effect on chemoresistance, although the mechanism was not yet fully understood. Purpose: To clarify the ability of CUR to intervene in the sensitivity of GC cells to Cisplatin (CDDP) by regulating the induction of ferroptosis through the P62/KEAP1/NRF2 pathway. Methods: An in vitro resistant cell line was established and treated with CUR for intervention. The synergy was evaluated using synergyfinder3.0 software. The impact of the combined use of CUR and CDDP on the proliferation, migration, and invasion of resistant GC cells was determined. The effect of CUR on ferroptosis in resistant GC cell lines was evaluated by measuring changes in reactive oxygen species (ROS) levels, malondialdehyde (MDA) levels, iron ion levels, and the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG). Western blotting was used to verify the expression changes of the ferroptosis-related indicator GPX4 and the differential expression of the antioxidant-related pathway P62/KEAP1/NRF2, validating the mechanism by which CUR induces ferroptosis in resistant GC cells. In vivo validation was performed using a xenograft mouse model. Results: The evaluation by synergy3.0 revealed a synergistic effect between CUR and CDDP. After treatment with CUR and CDDP, resistant GC cell lines exhibited reduced proliferation, migration, and invasion capabilities. Furthermore, the resistant GC cell lines underwent ferroptosis, with significant changes observed in ferroptosis-related indicators such as ROS, MDA, iron ions, and GSH/GSSG. The ferroptosis-related targets Glutathione Peroxidase 4 (GPX4) and the antioxidant pathway P62/KEAP1/NRF2 signaling pathway also showed significant changes. In in vivo validation, the combination of CUR and CDDP inhibited the growth of subcutaneous tumors and was found to be associated with the inhibition of subcutaneous xenografts and the GPX4 and P62/KEAP1/NRF2 signaling pathways. Conclusion: This study first revealed that CUR enhanced the sensitivity of cisplatin-resistant GC cells to CDDP by inducing ferroptosis. The combination of CUR and CDDP induces ferroptosis in cisplatin-resistant GC through the P62/KEAP1/NRF2 pathway.

Expansion of CD3+CD8+PD1+ T lymphocytes and TCR repertoire diversity predict clinical responses to adoptive cell therapy in advanced gastric cancer

The adoptive cell therapy (ACT) and delivery of ex vivo activated cellular products, such as dendritic cells (DCs), NK cells, and T cells, have shown promise for the treatment of gastric cancer (GC). However, it is unknown which cells can improve patient survival. This study was focused on the antitumour activity of a subset of these cellular products and their relationships with clinical outcomes. Nineteen patients were enrolled at the Capital Medical University Cancer Center, Beijing Shijitan Hospital, from June 1, 2013, to May 30, 2016. CD8⁺PD1⁺ T-cell sorting was carried out using flow cytometry, and the T-cell receptor (TCR) repertoire during ex vivo expansion for 15 days was analyzed by next-generation sequencing. After 15 days of culture, the number of CD8⁺ T cells had increased significantly, and the number of CD4⁺ T cells had increased correspondingly. After ex vivo expansion, CD8⁺ T cells exhibited significantly enhanced expression of PD-1, LAG-3, and TIM-3 but not 4-1BB. Survival analysis showed that patients with a pro/pre value of CD8⁺PD-1⁺ T cells >2.4 had significantly favorable overall survival (OS) (median OS time, 248 days versus 96 days, P=0.02) and progression-free survival (PFS) (median PFS time, 183 days vs. 77 days, P=0.002). The sorted CD8⁺PD-1⁺ T cells displayed enhanced antitumor activity and increased IFN-γ secretion after coculture with autologous tumor cell lines. TCR repertoire diversity was decreased after ex vivo expansion, which decreased the Shannon index and increased the clonality value. The prognosis of patients was significantly improved and was associated with the extent of CD8⁺PD-1⁺ T-cell expansion. In summary, this study showed that after ex vivo expansion for 15 days, CD8⁺PD-1⁺ T cells could be identified as tumor-reactive cells in patients treated for GC. Changing TCR species can predict the extent of CD3⁺CD8⁺PD1⁺ T-cell growth and the effect of ACT treatment.