title: Obesity hormone leptin induces growth and interferes with the cytotoxic effects of 5-fluorouracil in colorectal tumor stem cells.
abstract: The incidence of colon cancer has increased in developed countries, possibly due to sedentary lifestyle and high caloric diet. Experimental and epidemiological evidence suggests a link between colon cancer development and adipose tissue-derived circulating hormones. Leptin, a pluripotent cytokine secreted by adipocytes, is a key regulator of appetite and energy balance acting in the brain. On the other hand, leptin also controls many physiological and pathological processes in peripheral organs. Recent studies in colon cancer cell lines and human tumors suggested that leptin and its receptor (ObR) are implicated in colon carcinogenesis, and may serve as new biomarkers and pharmacological targets. Here, we explored, for the first time, whether leptin can affect the biology of colorectal tumor stem cells (CTSCs). We found that our previously established and characterized CTSC clones express ObR and respond to leptin with cell proliferation, activation of the extracellular signal-related kinase (ERK)1/2 and AKT signaling pathways, enhanced growth in soft agar, and improved sphere formation associated with E-cadherin overexpression. Moreover, leptin counteracted cytotoxic effects of 5-fluorouracil, a common colon cancer therapeutic agent. These results suggest that obesity and increased leptin levels might promote colorectal cancer by increasing growth and survival of CTSCs.
authors.affiliation: Department of Hematology, Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Bartucci
authors.forename: Susanne
authors.initials: S
authors.lastname: Svensson
authors.forename: Lucia
authors.initials: L
authors.lastname: Ricci-Vitiani
authors.forename: Rosanna
authors.initials: R
authors.lastname: Dattilo
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffoni
authors.forename: Michele
authors.initials: M
authors.lastname: Signore
authors.forename: Rita
authors.initials: R
authors.lastname: Ferla
authors.forename: Ruggero
authors.initials: R
authors.lastname: De Maria
authors.forename: Eva
authors.initials: E
authors.lastname: Surmacz
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D015153:Blotting, Western; D002448:Cell Adhesion; D002465:Cell Movement; D049109:Cell Proliferation; D003114:Colony-Forming Units Assay; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology*; D005472:Fluorouracil / Q000494:pharmacology*; D006801:Humans; D020738:Leptin / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D009765:Obesity; D054411:Receptors, Leptin / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D000964:Antimetabolites, Antineoplastic; D014408:Biomarkers, Tumor; C515448:LEPR protein, human; D020738:Leptin; D054411:Receptors, Leptin; D005472:Fluorouracil