Fig 2: ASF1A associates with RIF1.A, schematic representation of ASF1A and ASF1B protein structure. B, selected lists of ASF1A-associated proteins analyzed by mass spectrometry. C, selected lists of ASF1B-associated proteins analyzed by mass spectrometry. D, mock-transfected 293T cells or 293T cells transfected with constructs encoding SFB-tagged ASF1A or ASF1B were lysed and pulled down with streptavidin-conjugated beads. Pull-down samples were blotted using antibodies as indicated. E, cell lysates from 293T cells were immunoprecipitated (IP) with IgG, antibodies recognizing endogenous ASF1A or ASF1B, and the immunoprecipitates were blotted using antibodies as indicated. IgG, immunoglobulin G; RIF1, replication timing regulatory factor 1; SFB, S protein, FLAG, and streptavidin-binding peptide; 293T, human embryonic kidney 293T cell line.

Fig 3: Silencing of ASF1B attenuates the cisplatin resistance of gastric cancer cells. (A) HGC-27 and AGS cells were treated with different concentrations of cisplatin. After 48 h, cell viability was detected using Cell Counting Kit-8 assay. (B) IC50 of HGC-27 and AGS cells. (C) Proliferation of HGC-27 and AGS cells was evaluated using colony formation assay. (D) Flow cytometry was used to measure the apoptosis rate of HGC-27 and AGS cells. **P<0.01 compared with si-NC; ##P<0.05 compared with si-NC + cisplatin. ASF1B, anti-silencing function-1B; si, small interfering; NC, negative control.

Fig 4: ASF1B is highly expressed in GC tissues and cells. (A) TCGA database analysis showed that ASF1B expression was increased in GC tissues compared with healthy tissues. (B) Survival analysis was performed using the Kaplan-Meier method based on data from TCGA database. (C) RT-qPCR analysis was implemented to evaluate the expression level of ASF1B in GC tissues and adjacent healthy tissues of 25 patients with GC. (D) ASF1B mRNA expression in GES-1 cells and HGC-27 and AGS GC cells was measured using RT-qPCR. *P<0.05 and **P<0.01 compared with GES-1 or as indicated. GC, gastric cancer; TCGA, The Cancer Genome Atlas; RT-qPCR, reverse transcription-quantitative PCR; ASF1B, anti-silencing function-1B; TPM, transcripts per million; STAD, stomach adenocarcinoma.

Fig 5: Knockdown of ASF1B inhibits proliferation and induces apoptosis in gastric cancer cells. (A) Reverse transcription-quantitative polymerase chain reaction was performed to analyze the mRNA expression of ASF1B in HGC-27 and AGS cells. (B) ASF1B protein expression was detected by western blotting. (C) Cell Counting Kit-8 assay was conducted to assess the viability of HGC-27 and AGS cells. (D) Proliferation of HGC-27 and AGS cells was evaluated using colony formation assay. (E) Cell apoptosis in HGC-27 and AGS cells was estimated using flow cytometry. **P<0.01 compared with si-NC. ASF1B, anti-silencing function-1B; si, small interfering; NC, negative control.