Related Experiment Videos
Mitochondrial permeability transition is a central coordinating event in N-(4-hydroxyphenyl)retinamide-induced
1Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston 77030-4095, USA.
Abstract:
The inhibitory effects of N-(4-hydroxyphenyl)retinamide (4HPR) on the process of carcinogenesis are not fully understood and may result from its ability to induce apoptosis in transformed cells. This study investigated the apoptotic properties of 4HPR in four human cutaneous squamous cell carcinoma cell lines. Apoptosis induction, detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling method, occurred in a dose- and time-dependent fashion after treatment with 4HPR. 4HPR promoted reactive oxygen species (ROS) determined by oxidation of 2',7'-dichlorofluorescin. 4HPR-induced ROS, and apoptosis could be inhibited by L-ascorbic acid. Rhodamine 123 retention revealed that 4HPR treatment promoted a gradual dissipation of mitochondrial inner transmembrane potential, and this could be inhibited by L-ascorbic acid, implying that mitochondrial permeability transition was involved in apoptosis induction. Cyclosporin A and bongkrekic acid inhibited dissipation of mitochondrial inner transmembrane potential, ROS production, and DNA fragmentation after exposure to 4HPR, demonstrating that mitochondrial permeability transition was a central coordinating feature of 4HPR-induced apoptosis.
Insights
N-(4-hydroxyphenyl)retinamide (4HPR) induces apoptosis in skin cancer cells by promoting reactive oxygen species and mitochondrial dysfunction. L-ascorbic acid and mitochondrial inhibitors block these effects, highlighting 4HPR
Area of Science:
- Oncology
- Cell Biology
- Biochemistry
Background:
- Carcinogenesis is a complex process involving uncontrolled cell growth.
- N-(4-hydroxyphenyl)retinamide (4HPR) exhibits inhibitory effects on carcinogenesis.
- The precise mechanisms underlying 4HPR's anti-cancer activity, particularly apoptosis induction, require further elucidation.
Purpose of the Study:
- To investigate the apoptotic properties of 4HPR in human cutaneous squamous cell carcinoma (cSCC) cell lines.
- To elucidate the role of reactive oxygen species (ROS) and mitochondrial pathways in 4HPR-induced apoptosis.
Main Methods:
- Treatment of four human cSCC cell lines with varying doses and durations of 4HPR.
- Detection of apoptosis using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay.
- Measurement of ROS production via 2',7'-dichlorofluorescin oxidation.
- Assessment of mitochondrial inner transmembrane potential using Rhodamine 123 retention.
- Evaluation of the effects of L-ascorbic acid, Cyclosporin A, and bongkrekic acid on 4HPR-induced effects.
Main Results:
- 4HPR treatment resulted in dose- and time-dependent apoptosis induction in cSCC cells.
- 4HPR promoted ROS generation, which was inhibited by L-ascorbic acid.
- 4HPR induced dissipation of mitochondrial inner transmembrane potential, implicating mitochondrial permeability transition (MPT).
- Inhibition of MPT by Cyclosporin A and bongkrekic acid attenuated ROS production, DNA fragmentation, and apoptosis.
Conclusions:
- 4HPR effectively induces apoptosis in human cutaneous squamous cell carcinoma cells.
- ROS generation and mitochondrial permeability transition are critical mediators of 4HPR-induced apoptosis.
- These findings suggest that targeting mitochondrial pathways could be a therapeutic strategy for skin cancer.