Autophagy is recently receiving the spotlight as the development strategy for promising anticancer drugs. In particular, the majority of anticancer drugs originating from natural products are known to induce autophagy. Saururus chinensis has been used for treating various inflammatory diseases. Recent research has revealed that the extract of Saururus chinensis possess cytotoxicity for various types of human cancer cells. However, the exact action mechanism of Saururus chinensis extract for oral squamous cell carcinoma (OSCC) has not been studied yet. Therefore, the authors of this research aim to study the effect of methanol extract of S. chinensis (MESC) on OSCC cells. To observe the cell proliferation inhibitory effect of MESC on HSC3 cells, the authors conducted the trypan blue exclusion assay. Also, the action mechanism of MESC was studied by conducting the cell cycle analysis, acidic vesicular organelle (AVO) staining and flow cytometry analysis, monodansylcadaverine (MDC) staining, propidium iodide staining, and Western blotting on MESC-treated HSC3 cells. When HSC3 cells were treated in MESC, the cell proliferation was suppressed in time-dependent and dose-dependent manners. Also, the number of sub-G1 arrested cells increased in a dose-dependent manner. MDC punctate and AVO puncta significantly increased respectively. Western blot analysis demonstrated the expression of autophagy-related proteins increased, but apoptotic proteins were not observed. Also, the pAkt protein was reduced, while the p-p38 protein and pERK protein increased. According to our results, MESC induced autophagy and accompanied changes in the cell cycle in HSC3 cells. Also, the alteration in Akt, ERK, and p38 pathways were confirmed. This result suggested the possibility of MESC as the new promising adjuvant for treating OSCC patients.

Abstract
 Ⅰ. INTRODUCTION
 Ⅱ. MATERIALS and METHODS
  1. Chemicals
  2. HSC3 cell culture
  3. Reagents and antibiotics
  4. Analysis of cell viability
  5. Analysis of cell cycle distribution
  6. Analysis of MESC's cell death types and its mode of action
  7. AVO and MDC stain
  8. Statistical analysis
 Ⅲ. RESULTS
  1. Analysis of the changes in the cell viability for HSC3 cells
  2. Analysis of the cell cycle for HSC3 cells
  3. Analysis of the expression of apoptotic and autophagy related proteins
  4. Analysis of MESC's autophagy inducement ability
  5. Analysis of MESC-induced cell death mechanism
 Ⅳ. DISCUSSION
 REFERENCES

• 도미향(부산대학교 치의학전문대학원 구강생물공학연구소) | Mihyang Do (Research Institute for Oral Biotechnology, School of Dentistry, Pusan National University)
• 한혜연(부산대학교 치의학전문대학원 구강생물공학연구소) | Hye-Yeon Han (Research Institute for Oral Biotechnology, School of Dentistry, Pusan National University)
• 정성희(부산대학교 치의학전문대학원 구강내과학 교실) | Sung-Hee Jeong (Department of Oral Medicine, School of Dentistry, Dental Research Institute, Pusan National University)
• 김지연(부산대학교 치의학전문대학원 소아치과학 교실) | Jiyeon Kim (Department of Pediatric Dentistry, School of Dentistry, Dental Research Institute, Pusan National University)
• 유미현(부산대학교 치의학전문대학원 구강병리학 교실, BK21 플러스 사업단) | Mi Heon Ryu (Department of Oral Pathology, BK21 Plus project, School of Dentistry, Pusan National University) Correspondence