Targeting the EGF receptors on oral cancer cells with EGF

Authors

Jennifer Cheung, University of the Pacific
Takahiro Chino, University of the Pacific
Krystyna Knopka, University of the Pacific
Nejat Düzgüneş, University of the Pacific

Lead Author Affiliation

Biomedical Sciences

Introduction/Context/Diagnosis

The epidermal growth factor receptor (EGFR) may be useful in targeting oral squamous cell carcinoma (OSCC) cells to deliver suicide genes or photosensitizers. Using confocal microscopy, we investigated the binding of fluorescent EGF to the OSCC cell lines, HSC-3, CAL27 and H357 compared to non-tumor gingival epithelial cells (GECs) and GMSMK, transformed human oral keratinocytes. Our long-term goal is to utilize EGF bound to liposomes encapsulating photosensitizers to target oral cancer cells for photodynamic therapy and potentially other anti-cancer therapies.

Methods/Treatment Plan

HSC-3, CAL27 and H357 cells were seeded in 24-well culture plates on glass coverslips one day prior to incubation, at a density of 2.0 x 10⁵ cells per well in 1 ml of DME medium containing 10% fetal bovine serum, 2 mM L-glutamine, and antibiotics. Non-tumor GECs and GMSM-K cells were seeded under the same conditions in keratinocyte serum-free medium supplemented with prequalified human recombinant EGF 1-53 and Bovine Pituitary Extract. Cells were incubated at 37 degrees Celsius under 5% CO2. Biotinylated EGF complexed to Alexa Fluor® 488 streptavidin was added at 1 μg/ml to the cells for 15 min to 1 h. Cells were then processed for imaging with a confocal microscope.

Results/Outcome

GECs and GMSM-K cells showed minimal EGF binding after 15 min compared to HSC-3, CAL27 and H357 cells, which showed high levels of EGF binding as observed by the green fluorescence on the cell surface. With longer incubations of up to 1 h, perinuclear localization of EGF in OSCC cell lines was observed.

Significance/Conclusions

Selective toxicity to OSCC cells may be achieved by targeting liposomes to the EGFRs on these cells, since non-cancer cell lines appear to express significantly lower levels of EGFRs. Future studies will quantify bound EGF by flow cytometry, and the intracellular localization of EGF using fluorescent markers for organelles.

Comments/Acknowledgements

This work was presented at IADR/AADR March 24, 2017 (Abstract #2182) and funded by Research Pilot Project Award DRES03-Activity 113 from the University of the Pacific, Arthur A. Dugoni School of Dentistry.

Location

University of the Pacific, Dugoni Dental School, San Francisco, CA

Format

Poster

Poster Session

Faculty, Student, and Staff Presentations