Analysis of the effect of Cetuximab on fluorescence kinetics in living tongue cancer cells using the fluorescent ubiquitination-based cell cycle indicator (Fucci).

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K17171
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57060:Surgical dentistry-related
• Research Institution: Tokyo Medical and Dental University (2019-2020); Nagasaki University (2018)
• Principal Investigator: Okuyama Kohei 東京医科歯科大学, 大学院医歯学総合研究科顎口腔外科学分野, 非常勤講師 (30781968)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 抗EGFR抗体 / 細胞周期 / 細胞遊走 / Skp2 / p27 / Akt / mTOR / オートファジー

Outline of Final Research Achievements

The long-term cellular outcome of prolonged cetuximab treatment and the related molecular mechanism were explored in a tongue squamous cell carcinoma cell line constitutively expressing a fluorescent ubiquitination-based cell cycle indicator. Fluorescent time-lapse imaging and western blot analysis revealed prolonged cetuximab treatment decreased cell motility and enhanced G1 phase cell arrest in the central region of the colonies. Significantly decreased phosphorylation of retinoblastoma, Skp2, and Akt-mTOR proteins, accumulation of p27Kip1, and induction of type II LC3B were also observed. Results of the present study elucidate the cetuximab-dependent inhibition of cell migration, resulting in high cell density-related stress and persistent G1 arrest culminating in autophagy. These findings provide novel molecular insights related to the anti-tumor effects of prolonged cetuximab treatment with the potential to improve future therapeutic strategy.

Free Research Field

口腔腫瘍学

Academic Significance and Societal Importance of the Research Achievements

頭頸部癌に対するセツキシマブの適応拡大以来、良好な反応性が期待され、維持療法としての使用頻度も高まっている一方、その投与が長期化するケースも多い。本研究では、舌癌細胞における細胞周期動態を観察するとともに、細胞内タンパク発現動態を解析することで、セツキシマブ増感因子の同定を目的とした。その結果、p27の蓄積とオートファジーの誘導が生じていることが明らかとなった。これを糸口とし、細胞死への誘導や免疫原性の増加を付与する因子を同定し、修飾することでセツキシマブの治療効果を向上させる可能性がある。