RESUMEN
AIM:One of the important characteristics of the occurrence and development of triple-negative breast cancer(TNBC)is dysregulated cell metabolism.The aim of this study is to investigate the mechanism of pyruvate dehydrogenase E1 subunit alpha 1(PDHA1),a key enzyme component in aerobic glycolysis,affecting the proliferation,metastasis and invasion of TNBC.METHODS:(1)The expression levels of PDHA1 in breast cancer tissues and adja-cent tissues were analyzed by UALCAN database,KM-plotter database,Gene MANIA database and TCGA database.The expression of PDHA1 was compared according to tumor pathological stage,subtype classification and breast cancer bio-markers.The function of PDHA1 in TNBC was explored by gene enrichment analysis.(2)Immunohistochemistry assays were used to detect the expression of PDHA1 in human TNBC tissue and adjacent tissue samples.(3)Stable PDHA1 knockout and PDHA1 rescue TNBC MDA-MB-231 cells were constructed.The proliferation of MDA-MB-231 cells was de-tected by colony formation assay and cell counting assay.The regulatory effect of PDHA1 on the invasion and migration of MDA-MB-231 cells was detected by in vitro scratch assay and Transwell migration assay.RESULTS:Database analysis showed that the group with high PDHA1 expression in breast cancer had shorter survival and worse prognosis.In clinical specimens,the expression of PDHA1 in cancer tissues was higher than that in adjacent normal tissues.Knockout of PDHA1 inhibited the proliferation,metastasis,invasion and epithelial-mesenchymal transition of MDA-MB-231 cells.CONCLUSION:PDHA1 is overexpressed in TNBC,and it promotes cell proliferation and facilitates TNBC metastasis through the epithelial-mesenchymal transition pathway.
RESUMEN
Mammalian target of rapamycin (mTOR) controls cellular anabolism, and mTOR signaling is hyperactive in most cancer cells. As a result, inhibition of mTOR signaling benefits cancer patients. Rapamycin is a US Food and Drug Administration (FDA)-approved drug, a specific mTOR complex 1 (mTORC1) inhibitor, for the treatment of several different types of cancer. However, rapamycin is reported to inhibit cancer growth rather than induce apoptosis. Pyruvate dehydrogenase complex (PDHc) is the gatekeeper for mitochondrial pyruvate oxidation. PDHc inactivation has been observed in a number of cancer cells, and this alteration protects cancer cells from senescence and nicotinamide adenine dinucleotide (NAD+) exhaustion. In this paper, we describe our finding that rapamycin treatment promotes pyruvate dehydrogenase E1 subunit alpha 1 (PDHA1) phosphorylation and leads to PDHc inactivation dependent on mTOR signaling inhibition in cells. This inactivation reduces the sensitivity of cancer cells' response to rapamycin. As a result, rebooting PDHc activity with dichloroacetic acid (DCA), a pyruvate dehydrogenase kinase (PDK) inhibitor, promotes cancer cells' susceptibility to rapamycin treatment in vitro and in vivo.