Determination of Clonogenic Radiosensitivity of HeLa Cells in Early and Late G1 Phases.

BACKGROUND/AIM: Using a fluorescent ubiquitination-based cell cycle indicator (Fucci), we recently reported that post irradiation of HeLa cells, micronuclei frequency increased in the early G1 phase in comparison with that in the late G1 phase. This is inconsistent with the results of well-recognized studies that used clonogenic assays. In this study, we determined radiosensitivity of the cells using a clonogenic assay by making the best use of the Fucci property, while simultaneously characterizing cell cycle kinetics and DNA damage responses. MATERIALS AND METHODS: Early and late G1 phase cell fractions were isolated using a cell sorter by exploiting the different red fluorescence intensities of Fucci. Radiosensitivity was determined by the colony formation assay. Time-lapse imaging and immunostaining were performed to analyze cell cycle kinetics and DNA damage. RESULTS: Late G1 cells were more radioresistant than early G1 cells. Cells irradiated in the early and late G1 phases induced G2 arrest, while the latter demonstrated a significantly longer duration of G2 arrest. This difference became more evident as the radiation dose increased. Furthermore, 16 h after irradiation, a greater number of γH2AX foci remained in cells irradiated in the early G1 phase than in those irradiated in the late G1 phase. CONCLUSION: HeLa cells in the late G1 phase are more radioresistant than those in the early G1 phase, presumably because DNA damage is efficiently repaired during a longer G2 arrest in late G1 cells.

Comprehensive Genomic Profiling Reveals Clinical Associations in Response to Immune Therapy in Head and Neck Cancer.

Comprehensive genomic profiling (CGP) provides information regarding cancer-related genetic aberrations. However, its clinical utility in recurrent/metastatic head and neck cancer (R/M HNC) remains unknown. Additionally, predictive biomarkers for immune checkpoint inhibitors (ICIs) should be fully elucidated because of their low response rate. Here, we analyzed the clinical utility of CGP and identified predictive biomarkers that respond to ICIs in R/M HNC. We evaluated over 1100 cases of HNC using the nationwide genetic clinical database established by the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) and 54 cases in an institution-based study. The C-CAT database revealed that 23% of the cases were candidates for clinical trials, and 5% received biomarker-matched therapy, including NTRK fusion. Our institution-based study showed that 9% of SCC cases and 25% of salivary gland cancer cases received targeted agents. In SCC cases, the tumor mutational burden (TMB) high (≥10 Mut/Mb) group showed long-term survival (>2 years) in response to ICI therapy, whereas the PD-L1 combined positive score showed no significant difference in progression-free survival. In multivariate analysis, CCND1 amplification was associated with a lower response to ICIs. Our results indicate that CGP may be useful in identifying prognostic biomarkers for immunotherapy in patients with HNC.

Clinical utility of comprehensive genomic profiling in Japan: Result of PROFILE-F study.

INTRODUCTION: Clinical sequencing has provided molecular and therapeutic insights into the field of clinical oncology. However, despite its significance, its clinical utility in Japanese patients remains unknown. Here, we examined the clinical utility of tissue-based clinical sequencing with FoundationOne® CDx and FoundationOne® Heme. Between August 2018 and August 2019, 130 Japanese pretreated patients with advanced solid tumors were tested with FoundationOne® CDx or FoundationOne® Heme. RESULTS: The median age of 130 patients was 60.5 years (range: 3 to 84 years), and among them, 64 were males and 66 were females. Major cancer types were gastrointestinal cancer (23 cases) and hepatic, biliary, and pancreatic cancer (21 cases). A molecular tumor board had been completed on all 130 cases by October 31, 2019. The median number of gene alterations detected by Foundation testing, excluding variants of unknown significance (VUS) was 4 (ranged 0 to 21) per case. Of the 130 cases, one or more alterations were found in 123 cases (94.6%), and in 114 cases (87.7%), actionable alterations with candidates for therapeutic agents were found. In 29 (22.3%) of them, treatment corresponding to the gene alteration was performed. Regarding secondary findings, 13 cases (10%) had an alteration suspected of a hereditary tumor. Of the 13 cases, only one case received a definite diagnosis of hereditary tumor. CONCLUSIONS: Our study showed that clinical sequencing might be useful for detecting gene alterations in various cancer types and exploring treatment options. However, many issues still need to be improved.

A Pilot Study Analyzing the Clinical Utility of Comprehensive Genomic Profiling Using Plasma Cell-Free DNA for Solid Tumor Patients in Japan (PROFILE Study).

BACKGROUND: The clinical utility of plasma cell-free DNA in precision cancer medicine has not been established. A pilot study was conducted to investigate the clinical utility of comprehensive genomic profiling by liquid biopsy in a Japanese population. METHODS: In this PROFILE study, 102 patients with advanced solid tumors who showed progression with standard systemic therapy underwent liquid biopsy between August 2017 and February 2020. Liquid biopsy was performed using Guardant360. RESULTS: Of the 102 patients, 56 were women, and the median age was 65 years. Regarding the types of cancer, 31 were hepatobiliary and pancreatic cancer, 17 were gastrointestinal cancer, and 13 were breast cancer. Frequently altered genes were TP53 (53.9%, 46/102), KRAS (25.5%, 26/102), PIK3CA (19.6%, 20/102), and EGFR (17.6%, 18/102). At least one genetic aberration was detected in 92 patients (90.2%). Actionable mutation was discovered in 88 patients (86.3%), and 67 patients (65.7%) were clinical trial candidates. Of the 102 patients, 22 (21.6%) were able to receive biomarker-matched therapy. Their best responses were as follows: 1 complete response, 3 partial responses, 7 stable diseases, and 11 progressive diseases. Additionally, the treated patients were divided on the basis of matching scores (≥ 50% vs. < 50%). The patients were divided into high and low groups. The high group had a higher disease control rate (DCR) of 75% compared with 20% in the low group (P = 0.010). CONCLUSIONS: The results indicate that liquid biopsy is useful for identifying actionable mutations associated with the clinical response of selected patients.