Identification of miR-16/29 targets in adipocytes by LC-MSMS

Cancer cachexia is a multifactorial metabolic syndrome defined by the rapid loss of skeletal muscle mass and the loss of fat mass. Up 80% of cancer patients at the late stage with cachexia suffer from progressive atrophy of adipose tissue. Unlike studies on skeletal muscle wasting, there is limited research on fat loss in cachexia. It was noted that most patients suffer from fat loss as cancer progress. Fat loss precedes muscle loss, is associated with shorter survival, and is variable to timing and intensity in various cancer populations. Increased lipolysis may be the leading cause of fat loss in cancer cachexia. miRNAs are a class of non-coding RNAs of 19~25 nucleotides that regulate gene silencing by interacting with the 3’ untranslated region (UTR) of target mRNA to cause mRNA degradation and translational repression. miRNAs play multifaceted roles in pancreatic cancer proliferation, survival, metastasis, and chemoresistance. Aberrant expression of miRNA in circulating exosomes may play potential roles in modulating fat loss in cancer cachexia. We identified 2 miRNAs, miR-16 and miR-29, which have 2-fold higher expression existed in at PDAC cells. To explore which genes in adipogenesis and lipolysis were directly affected by miR-16-5p or/and miR-29a-3p, we analyzed the targets which were down-regulated in both miR-16-5p and miR-29a-3p-transfected 3T3-L1 cells by mass analysis.