Discipline: Biological Sciences
Subcategory: Cancer Research
Terron S. Adlam - Delaware State University
Co-Author(s): Opeyemi Akinrinsola, Delaware State University, Dover, DE
CD44 and podoplanin (encoded by PDPN) are cell membrane receptors involved in several human tumors, including head and neck squamous cell carcinoma (HNSCC) and breast cancer. These two proteins have been shown to interact and to promote a more aggressive cancer phenotype by increasing cell migration and invasion, which promotes metastasis. In HNSCC cells CD44 and PDPN are concurrently up-regulated. The mechanism(s) by which these genes appear to be co-regulated is not well understood. However, a preliminary bioinformatics analysis of the PDPN promoter region has uncovered the presence a CD44 intracytoplasmic domain (CD44-ICD) response element (CIRE, cctgcg). Therefore, based on this finding, we hypothesize that CD44 can transcriptionally regulate the expression of PDPN via the CD44-ICD. To test this hypothesis we first have carried out RT-PCR and western blotting using MCF-7 (CD44 negative) and MCF-7/CD44s (a stable transfectant for CD44 standard) total RNA and whole cell lysates, respectively. While the absence of CD44s mRNA and protein expression correlated with a similar absence of podoplanin in MCF-7 cells, the forced expression of CD44s in MCF-7/CD44s promoted the expression of PDPN mRNA and podoplanin. To determine whether the CD44-ICD is bound to the PDPN promoter-associated CIRE in MCF-7/CD44 cells (podoplanin positive), chromatin immunoprecipitation (ChIP) assays will be performed. MCF-7/CD44 (podoplanin positive) and MCF-7 (podoplanin negative) cells will be also transfected with CD44-targeting shRNA and CD44-expressing constructs, respectively, to assessed the effect on PDPN mRNA and protein expression. These findings begin to clarify a potential functional association between podoplanin and CD44, which in breast cancer cells appear to increase the malignant phenotype.
Funder Acknowledgement(s): NSF HBCU-UP HRD-1533631
Faculty Advisor: Karl E. Miletti-Gonzalez,