Effects of methylene blue photodynamic therapy on oral carcinoma and leukoplakia cells

Mina N. Le, Beverly R Wuertz, Merrill A. Biel, Rachel L. Thompson, Frank G. Ondrey

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Objective: Methylene blue (MB) is a readily available and affordable substrate that can be used as a photosensitizer for photodynamic therapy (PDT). The objective of this study was to determine if PDT with MB can downregulate matrix metalloproteinases (MMPs) related to oral carcinoma. Methods: Cell cultures of oral squamous cell carcinoma (CA-9-22), oral leukoplakia (MSK-Leuk1), and immortalized keratinocytes (Rhek-1A) were photosensitized with MB and treated with PDT. MMP-9 gene expression was interrogated via qRT-PCR. The 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to confirm the efficacy of MB PDT. Results: MMP-9 gene expression was found to be significantly decreased in oral carcinoma, leukoplakia, and immortalized keratinocytes with use of MB PDT. Conclusion: This work demonstrates that MB-mediated PDT can downregulate MMPs which are critical to the invasion and metastasis of oral cancer. These results suggest that MB PDT could be a clinically significant and cost-effective treatment for oral leukoplakia and carcinoma. Level of Evidence: NA.

Original languageEnglish (US)
Pages (from-to)982-987
Number of pages6
JournalLaryngoscope investigative otolaryngology
Issue number4
StatePublished - Aug 2022

Bibliographical note

Funding Information:
The authors wish to acknowledge the Lions International Medical Research Foundation who provided funding for this project through the Lions 5M Club of Minnesota.

Publisher Copyright:
© 2022 The Authors. Laryngoscope Investigative Otolaryngology published by Wiley Periodicals LLC on behalf of The Triological Society.


  • molecular biology
  • oral cavity
  • oropharynx

PubMed: MeSH publication types

  • Journal Article


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