Related Experiment Video
Updated: Jun 23, 2026
Curcuminoid-Mediated Antimicrobial Photodynamic Therapy on a Murine Model of Oral Candidiasis
Published on: October 27, 2023
Metformin enhances methylene blue-mediated photodynamic therapy in oral squamous cell carcinoma
Mohamed A Osman1, Marwa Sharaky2, Hesham Abdel-Fattah3
1Dental Unit, Surgical Oncology Department, National Cancer Institute, Cairo University, Cairo, Egypt. std.mohamedosaman@niles.edu.eg.
Background:
Head and neck squamous cell carcinoma (HNSCC) is the most common malignancy of the head and neck region with relatively low survival rate and response and high resistance to treatment. Tongue and floor of the mouth are the most commonly involved sites. New therapies for oral squamous cell carcinoma (OSCC) treatment are still required. An attractive option for the treatment of OSCC is the use of photodynamic therapy (PDT). Considering metformin's potential to reduce cancer risk and inhibit proliferation, therefore the present study aims to evaluate its ability to potentiate the methylene blue-mediated photodynamic effect against the growth of tongue cancer cells in vitro and the possible molecular mechanisms of action involved.
Methods:
Cytotoxic activity of metformin (MF) and/or Methylene blue (MB)+laser light (L) against the growth of HNO97 tongue cells was determined using the sulforhodamine (SRB) method. Several protein expressions were determined using ELISA kits include mechanistic target of rapamycin (mTOR), AMP-activated protein kinase (AMPK), B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and caspase 8.
Results:
Laser light at different energy per surface area induced inhibition in the surviving fraction of HNO97 cells, while in presence of MB (10 µg/ml for 4 h.), the surviving fractions showed more inhibition. Addition of MF (1000 µg/ml, for 24 h.) to MB + L induced significant 51 and 89% inhibition of cell survival at energy level of 45 and 337.5 J/cm2, respectively. Addition of Metformin to MB-photodynamic therapy also increased the expression AMPK and decrease the expression of mTOR at the protein level. Moreover there were increase in Bax expression and decrease in Bcl2 expression with significant increase in caspase 8 expression at the protein level.
Conclusion:
Such combined treatment showed promising synergistic interaction via several molecular pathways, which is well tolerated and readily applicable strategy to improve the therapeutic outcome of PDT in cancer cell treatment.
Insights
Metformin enhances photodynamic therapy for tongue cancer by increasing cell death and altering key protein expressions. This combined approach shows promise for improving cancer treatment outcomes.
Area of Science:
- Oncology
- Photochemistry
- Molecular Biology
Background:
- Head and neck squamous cell carcinoma (HNSCC) has a poor prognosis and high treatment resistance.
- Oral squamous cell carcinoma (OSCC) necessitates novel therapeutic strategies.
- Photodynamic therapy (PDT) presents a promising option for OSCC treatment.
Purpose of the Study:
- To evaluate metformin's potentiation of methylene blue-mediated photodynamic therapy (MB-PDT) against tongue cancer cells.
- To investigate the molecular mechanisms underlying the combined treatment's efficacy.
Main Methods:
- Cytotoxicity was assessed using the sulforhodamine (SRB) method.
- Protein expression levels of mTOR, AMPK, Bcl-2, Bax, and caspase 8 were quantified using ELISA kits.
Main Results:
- MB-PDT significantly inhibited HNO97 tongue cancer cell survival.
- Metformin addition to MB-PDT resulted in 51% and 89% cell inhibition at specific energy levels.
- Combined treatment modulated AMPK, mTOR, Bax, Bcl-2, and caspase 8 protein expressions.
Conclusions:
- The combination of metformin and MB-PDT demonstrates a synergistic interaction against tongue cancer cells.
- This strategy modulates key molecular pathways involved in cell survival and apoptosis.
- The combined treatment is well-tolerated and applicable for enhancing PDT outcomes in cancer therapy.
Related Concept Videos
01:26Oral Hypoglycemic Agents: Biguanides and Glitazones
01:11Pharmacogenetics of Drug Targets: β₂-Adrenergic Receptors, Apo E, Thymidylate Synthase