TARGETING ENZYMES OF SPHINGOLIPID METABOLISM IN TREATMENT OF COLORECTAL CANCER

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Conor Miller Pumphrey (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: Alterations in sphingolipid (SL) metabolism can contribute to cancer progression as well as chemotherapy resistance. Thus , the enzymes of SL metabolism are exploitable targets for the development of novel therapeutics. Colorectal cancer (CRC) cells characteristically have elevated levels of glucosylceramide synthase (GCS) , acid ceramidase (AC) , and sphingosine kinase 1 (SPHK1) enzymes that can contribute to cancer cell growth. For this reason , we were interested in determining the impact of inhibitors of SL enzymes on human CRC cell viability. The effects of our pharmacological inhibitors on CRC cell growth were investigated using a standard 96-well viability assay. Potency was gauged by evaluating inhibitor IC50 values (the half-maximal inhibitory concentration , meaning the dose required to kill 50% of the cells). The human CRC cell lines , LoVo and HT-29 , were employed in all experiments. GCS inhibitors used were PPMP , Eliglustat , and PDMP. AC inhibitors included DM-102 and SACLAC , whereas the SPHK1 inhibitors tested were FTY-720 , SK1-I , and PF-543. The most promising results were obtained in experiments using the HT-29 cell line. In HT-29 cells , FTY-720 was the most potent SPHK1 inhibitor , with an IC50 value of 7.0 µM. GCS was another enzyme that was effectively suppressed , in this instance by introduction of PPMP (IC50 = 3.5 µM). Finally , of the two AC inhibitors , SACLAC demonstrated the highest potency (IC50 = 9.5 µM). Of the enzymes assessed , our results suggest that pharmacological inhibition of GCS is the most promising strategy for inhibition of CRC cell growth.

Additional Information

Publication

Thesis

Language: English

Date: 2019

Keywords

Sphingolipid, cancer, chemotherapy resistance, glucosylceramide synthase, acid ceramidase, sphingosine kinase, viability assay, LoVo, HT-29, pharmacological inhibition

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