Objective:

To investigate the antitumor effect and underlying mechanism of alectinib combined with 5-aminolevulinic acid-based photodynamic therapy (ALA-PDT) on endometrial cancer cells via targeting FECH.

Approach:

• Cell Lines: In vitro study on human endometrial cancer Ishikawa (ISK) and HEC-1-A cell lines.
• Cytotoxicity Assay: Cytotoxicity of alectinib was assessed using CCK8 assay to determine optimal concentration.
• Microscopy and Staining: Confocal laser microscopy was used to observe PpIX localization; ROS generation was detected by fluorescent probe staining.
• Gene and Protein Expression: qPCR and Western blotting measured mRNA and protein levels of FECH after alectinib treatment.
• Apoptosis Quantification: Annexin V-AF647/PI staining combined with flow cytometry quantified apoptotic rates post-treatment.

Key Findings:

• Alectinib's IC50 values were 38.83 μM for ISK and 42.70 μM for HEC-1-A cells.
• PpIX co-localized with mitochondria, showing higher fluorescence intensity in alectinib and ALA groups compared to control.
• Combination treatment with alectinib and ALA-PDT promoted ROS accumulation and reduced heme levels.
• Alectinib treatment increased FECH mRNA and protein expression significantly (P<0.05).
• Combined treatment induced a higher apoptosis rate than ALA or alectinib alone.

Interpretation:

Alectinib may enhance the efficacy of ALA-PDT in endometrial cancer by targeting FECH, promoting PpIX accumulation and apoptosis.

Limitations:

• Study conducted in vitro; results may not directly translate to clinical settings.
• Further research needed to explore the in vivo efficacy and safety of the combination treatment.

Conclusion:

Alectinib targets FECH activity to enhance mitochondrial PpIX accumulation, leading to increased apoptosis in endometrial cancer cells when combined with ALA-PDT.