leptin and Cholangiocarcinoma

Biliary tract cancers are rare, with a poor patient prognosis. Leptin and programmed death-ligand 1 (PD-L1) influence CD8. Immunohistochemistry for leptin signaling-related proteins (leptin, leptin receptor, pSTAT3, extracellular-regulated kinase, mammalian target of rapamycin), PD-L1, CD8, and FOXP3 and in situ hybridization for Epstein-Barr virus-encoded small RNAs were performed in 147 cases of surgically-resected biliary tract cancers.. Immune cell PD-L1-positivity, tumor size < 3 cm, adjuvant chemotherapy, no recurrence, and early-stage tumors were correlated with better 5-year survival in the tumoral PD-L1. The prognostic implication of the variables may depend upon tumoral protein expression and the anatomical site. Immune cell PD-L1-positivity and the administration of adjuvant chemotherapy may indicate the favorable survival of patients with surgically-resected biliary tract cancers, specifically, in the tumoral PD-L1

Topics: B7-H1 Antigen; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Biliary Tract Neoplasms; Biomarkers, Tumor; CD8-Positive T-Lymphocytes; Cholangiocarcinoma; Epstein-Barr Virus Infections; Forkhead Transcription Factors; Herpesvirus 4, Human; Humans; Leptin; Lymphocytes, Tumor-Infiltrating; Prognosis

Leptin is an adipokine minimally known for its activities or underlying mechanisms in cholangiocarcinoma. The present study explored the effects of leptin on the epithelial‑mesenchymal transition (EMT) and pro‑angiogenic capability of cholangiocarcinoma cells, and investigated the underlying mechanisms. Cholangiocarcinoma cells were treated with leptin, and their migration and invasion rates were investigated using Transwell assays. Furthermore, conditioned medium was collected from cholangiocarcinoma cells following leptin treatment and applied to human umbilical vein endothelial cells to assess tube formation. The expression of EMT and pro‑angiogenic factors was examined by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analyses. Mechanistically, the function of pyruvate kinase muscle isozyme M2 (PKM2) was assessed in leptin‑induced phenotypes using siRNA targeting PKM2 (si‑PKM2). Bioinformatics screening and luciferase reporter assays were used to reveal microRNA (miR)‑122 as the potential mediator between leptin and PKM2. Finally, the associations between leptin and miR‑122 or PKM2 levels in patients with cholangiocarcinoma were assessed by ELISA and RT‑qPCR. Leptin significantly increased the EMT and pro‑angiogenic capability of cholangiocarcinoma cells, visibly inhibited endogenous miR‑122 expression, and upregulated PKM2. Furthermore, si‑PKM2 inhibited leptin‑induced migration, invasion, EMT‑associated marker expression levels and the pro‑angiogenic capability in cholangiocarcinoma cells. In addition, miR‑122 negatively regulated the expression of PKM2. When applied together with leptin, miR‑122 was sufficient to reverse the multiple malignancy‑promoting effects of leptin. Consistently, the serum leptin level positively correlated with that of PKM2, but negatively with that of miR‑122 in patients with cholangiocarcinoma. Leptin, by downregulating miR‑122 and elevating PKM2 expression, acts as a pleiotropic pro‑malignancy cytokine for cholangiocarcinoma. Therefore, increasing miR‑122 expression and inhibiting PKM2 may be future approaches for cholangiocarcinoma treatment.

Topics: Bile Duct Neoplasms; Carrier Proteins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cholangiocarcinoma; Culture Media, Conditioned; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic; Human Umbilical Vein Endothelial Cells; Humans; Leptin; Membrane Proteins; MicroRNAs; Thyroid Hormone-Binding Proteins; Thyroid Hormones

Cholangiocarcinoma is a strongly aggressive malignancy with a very poor prognosis. Effective therapeutic strategies are lacking because molecular mechanisms regulating cholangiocarcinoma cell growth are unknown. Furthermore, experimental in vivo animal models useful to study the pathophysiologic mechanisms of malignant cholangiocytes are lacking. Leptin, the hormone regulating caloric homeostasis, which is increased in obese patients, stimulates the growth of several cancers, such as hepatocellular carcinoma. The aim of this study was to define if leptin stimulates cholangiocarcinoma growth. We determined the expression of leptin receptors in normal and malignant human cholangiocytes. Effects on intrahepatic cholangiocarcinoma (HuH-28) cell proliferation, migration, and apoptosis of the in vitro exposure to leptin, together with the intracellular pathways, were then studied. Moreover, cholangiocarcinoma was experimentally induced in obese fa/fa Zucker rats, a genetically established animal species with faulty leptin receptors, and in their littermates by chronic feeding with thioacetamide, a potent carcinogen. After 24 weeks, the effect of leptin on cholangiocarcinoma development and growth was assessed. Normal and malignant human cholangiocytes express leptin receptors. Leptin increased the proliferation and the metastatic potential of cholangiocarcinoma cells in vitro through a signal transducers and activators of transcription 3-dependent activation of extracellular signal-regulated kinase 1/2. Leptin increased the growth and migration, and was antiapoptotic for cholangiocarcinoma cells. Moreover, the loss of leptin function reduced the development and the growth of cholangiocarcinoma. The experimental carcinogenesis model induced by thioacetamide administration is a valid and reproducible method to study cholangiocarcinoma pathobiology. Modulation of the leptin-mediated signal could be considered a valid tool for the prevention and treatment of cholangiocarcinoma.

Topics: Animals; Bile Duct Neoplasms; Bile Ducts; Bile Ducts, Intrahepatic; Cell Proliferation; Cholangiocarcinoma; Fluorescent Antibody Technique; Humans; Janus Kinases; Leptin; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinase Kinases; Phosphorylation; Proto-Oncogene Proteins c-akt; Rats; Rats, Zucker; Receptors, Leptin; Reverse Transcriptase Polymerase Chain Reaction; STAT3 Transcription Factor; Thioacetamide