No abstract

Radiosensitivity of glioblastoma cells were preferentially enhanced by pre-irradiation DSF treatment compared to normal cell, especially radioresistant cells such as MGMT-wt cells. Induction of apoptosis or inhibition of DNA damage repair may underlie DSF-induced radiosensitization. Clinical benefit of combining DSF with radiotherapy should be investigated in the future.

OBJECTIVE To investigate the effects of survivin gene RNA interference on cell growth and the cell cycle in the human bladder cancer cell line T24. MATERIALS AND METHODS A small interfering RNA (siRNA) targeting survivin was transfected into T24 cells using a liposome approach. Reverse transcription‐polymerase chain reaction and Western blot analysis were used to examine survivin gene expression in T24 cells. Cells densities were determined by haematocytometer counts and flow cytometry was used for cell cycle analysis. Caspase‐3 activity was quantified. RESULTS After treatment with survivin siRNA, the survivin gene expression in T24 cells was almost completely absent. The survivin siRNA treatment caused a profound decrease in survivin protein, which was correlated with a decrease in cell growth, G2/M arrest, and an increase in the fraction of cells undergoing apoptosis. The inhibition of survivin expression increased caspase‐3 activity in T24 cells, which led to apoptosis. CONCLUSIONS RNA interference can efficiently suppress survivin expression in T24 cells. Targeting survivin by siRNA may be a promising approach to block proliferation of bladder cancer cells and may provide a suitable adjuvant therapy for treatment of bladder cancer.

The time-sequential change in immune-related gene expression of the glioblastoma cell line after irradiation was evaluated to speculate the effect of combined immunotherapy with radiotherapy. The U373 MG glioblastoma cell line was irradiated with 6 Gy single dose. Next-generation sequencing (NGS) transcriptome data was generated before irradiation (control), and at 6, 24, and 48 hours post-irradiation. Immune-related pathways were analyzed at each time period. The same analyses were also performed for A549 lung cancer and U87 MG glioblastoma cell lines. Western blotting confirmed the programmed death-ligand 1 (PD-L1) expression levels over time. In the U373 MG cell line, neutrophil-mediated immunity, type I interferon signaling, antigen cross-presentation to T cell, and interferon-γ signals began to increase significantly at 24 hours and were upregulated until 48 hours after irradiation. The results were similar to those of the A549 and U87 MG cell lines. Without T cell infiltration, PD-L1 did not increase even with upregulated interferon-γ signaling in cancer cells. In conclusions, In the glioblastoma cell line, immune-related signals were significantly upregulated at 24 hours after irradiation. Therefore, the time interval between daily radiotherapy might not be enough to expect full immune responses by combined immune checkpoint inhibitors and newly infiltrating immune cells after irradiation.

The time-sequential change in immune-related gene expression of the glioblastoma cell line after irradiation was evaluated to speculate the effect of combined immunotherapy with radiotherapy. The U373 MG glioblastoma cell line was irradiated with 6 Gy single dose. Next-generation sequencing (NGS) transcriptome data was generated before irradiation (control), and at 6, 24, and 48 h post-irradiation. Immune-related pathways were analyzed at each time period. The same analyses were also performed for A549 lung cancer and U87 MG glioblastoma cell lines. Western blotting confirmed the programmed death-ligand 1 (PD-L1) expression levels over time. In the U373 MG cell line, neutrophil-mediated immunity, type I interferon signaling, antigen cross-presentation to T cell, and interferon- γ signals began to increase significantly at 24 h and were upregulated until 48 h after irradiation. The results were similar to those of the A549 and U87 MG cell lines. Without T cell infiltration, PD-L1 did not increase even with upregulated interferon- γ signaling in cancer cells. In conclusions, in the glioblastoma cell line, immune-related signals were significantly upregulated at 24 and 48 h after irradiation. Therefore, the time interval between daily radiotherapy might not be enough to expect full immune responses by combined immune checkpoint inhibitors and newly infiltrating immune cells after irradiation.