Human adipose-derived stem cells promote migration of papillary thyroid cancer cell via leptin pathway.

Introduction: Obesity is associated with the incidence and poor prognosis of thyroid cancer, but the mechanism is not fully understood. The aim of this study was to investigate the effects of human adipose-derived stem cells (ADSCs) on the invasion and migration of thyroid cancer cells.

Methods: ADSCs-conditioned medium (ADSC-CM) was collected to culture thyroid cancer cell lines TPC-1 cells and BCPAP cells. The effects of ADSCs on thyroid cancer cell proliferation were determined by CCK8 and EdU assays, and the effects on migration were determined by Transwell and wound closure assays. Leptin neutralizing antibodies (NAB) were added to ADSC-CM to block leptin. In animal experiments, TPC-1 cells and BCPAP cells were injected into the tail vein of nude mice, and the leptin receptor antagonist peptide allo-aca was injected subcutaneously to block the leptin pathway. The number and size of metastatic lung tumours were observed after 8 weeks.

Results: ADSC-CM significantly promoted the invasion and migration of thyroid cancer cells and upregulated their matrix metalloproteinase 2 (MMP-2) levels, while NAB with the addition of leptin reduced the invasion and migration of thyroid cancer cells and downregulated MMP-2 levels. Allo-aca treatment reduced the number of metastatic lung nodules formed by thyroid cancer cells in nude mice and reduced the diameter of metastatic lesions.

Conclusion: ADSCs upregulate MMP-2 levels of thyroid cancer cells through exocrine leptin, thereby promoting cancer cell migration, which may be one of the key mechanisms by which obesity increases the invasiveness of thyroid cancer.