[Melatonin in in vitro apoptosis of H22 hepatocarcinoma cells]
Li-hua Gong1, Da-hong Ren, Mi Xiong
1Department of Pathology, Tongji Medical College, Huazhong Uninersity of Science and Technology, Wuhan 430030, China.
Objective:
To study the effect of melatonin (MLT) in in vitro apoptosis of hepatocarcinoma cells and its mechanism.
Methods:
The apoptotic cells, bcl-2 and bax were detected through immunocytochemical method (ICC) and Tolt-mediated x-duTP nick end labeling (TUNEL). Computer image analysis system was used to quantify the expression of bcl-2 and bax by detecting the absorbance value of positive products. Apoptosis index (AI) was used to quantify the number of apoptotic cells.
Results:
In vitro, AI increase was both concentration- and time-dependent through TUNEL. During the same duration, AI of medium dose group was higher than that of low dose and control group (P < 0.05); AI of high dose, medium dose and 5-Fu group were higher than those of low dose and control group (P < 0.01), however, there was no significant difference between the low dose and control group (P > 0.05). At the same dose, in high dose, medium dose and 5-Fu group, the change of AI showed significant difference from 24 to 36 hours (P < 0.05). The expression of bcl-2 was down-regulated as the MLT increased, and there was significant difference between the low dose and control group (P < 0.01). But, the expression of bax was up-regulated as the dose of MLT increased, showing significant difference between the high dose and control groups (P < 0.01). As time went on, the expression of bcl-2 was decreased and in every group, with the change in absorbance value of bcl-2 significantly different from 24 to 36 hours (P < 0.05), whereas that of bax remained almost unchanged. The ratio of bax/bcl-2 was increased with the increase in the concentration of MLT.
Conclusion:
Melatonin may induce apoptosis in the hepatocarcinoma cells which is concentration- and time-dependent, in which bcl-2 and bax are involved.
Insights
Melatonin (MLT) induces apoptosis in hepatocarcinoma cells in a dose- and time-dependent manner. This process involves the regulation of bcl-2 and bax protein expression, impacting cancer cell survival.
Area of Science:
- Cell Biology
- Molecular Oncology
- Biochemistry
Context:
- Hepatocellular carcinoma (HCC) is a significant global health concern.
- Understanding the molecular mechanisms of apoptosis induction is crucial for developing novel cancer therapies.
- Melatonin's potential role in cancer treatment warrants further investigation.
Purpose:
- To investigate the in vitro effects of melatonin (MLT) on hepatocarcinoma cell apoptosis.
- To elucidate the underlying molecular mechanisms, focusing on the expression of bcl-2 and bax proteins.
- To determine the concentration- and time-dependency of MLT-induced apoptosis.
Summary:
- Melatonin treatment increased the apoptosis index (AI) in hepatocarcinoma cells in a concentration- and time-dependent manner.
- Melatonin downregulated bcl-2 expression while upregulating bax expression, leading to an increased bax/bcl-2 ratio.
- These findings were confirmed using TUNEL assays and immunocytochemical detection of apoptosis-related proteins.
Impact:
- Melatonin demonstrates potential as an apoptosis-inducing agent against hepatocarcinoma cells.
- The study provides insights into the molecular pathways targeted by melatonin in cancer cells.
- This research may contribute to the development of melatonin-based therapeutic strategies for liver cancer.
