AdipoRon Affects Cell Cycle Progression and Inhibits Proliferation in Human Osteosarcoma Cells

Abstract

AdipoRon (AdipoR) is the first synthetic molecule acting as a selective and potent adiponectin receptor agonist. Recently, the possible pharmacological use of AdipoR in different pathological conditions has been addressed. Interestingly, initial evidence suggests that AdipoR may have anticancer properties in different preclinical models, such as pancreatic and ovarian cancer. To our knowledge, so far no research has been directed at determining the impact of AdipoR on osteosarcoma, the most aggressive and metastatic bone malignancy occurring in childhood and adolescence age. Here, we investigate the possible antitumor effects of AdipoR in osteosarcoma cell lines. MTT and cell growth curve assays clearly indicate that AdipoR inhibits, at different extents, proliferation in both U2OS and Saos-2 osteosarcoma cell lines, the latter being more sensitive. Moreover, flow cytometry-based assays point out a significant G0/G1 phase accumulation and a contemporary S phase decrease in response to AdipoR. Consistent with the different sensitivity, a strong subG1 appearance in Saos-2 after 48 and 72 hours of treatment is also observed. The investigation of the molecular mechanisms highlights a common and initial ERK1/2 activation in response to AdipoR in both Saos-2 and U2OS cells. Interestingly, a simultaneous and dramatic downregulation of p70S6K phosphorylation, one of the main targets of mTORC1 pathway, has also been observed in AdipoR-treated Saos-2, but not in U2OS cells. Importantly, a strengthening of AdipoR-induced effects was reported upon everolimus-mediated mTORC1 perturbation in U2OS cells. In conclusion, our findings provide initial evidence of AdipoR as an anticancer molecule differently affecting various signaling pathways involved in cell cycle and cell death in osteosarcoma cells and encourage the design of future studies to further understand its pattern of activities.

Adiponectin signalling in bone homeostasis, with age and in disease

“… 105 By contrast, the adiponectin receptor agonist, AdipoRon, decreased the proliferation of Saos-2 cells in vitro. 106 Given that AdipoR1 has a higher affinity for globular adiponectin, it is possible that increased signalling through AdipoR1 compared to AdipoR2 may promote abnormal osteoblast proliferation contributing to osteosarcoma, whilst equal signalling through both receptors may be important to control normal proliferative responses in healthy bone. Indeed, the loss of AdipoR1 has been linked to reduced osteoblast survival in vitro, 24 and absolute number in vivo 53 under healthy conditions (as described — In health and ageing ) and may represent a novel therapeutic strategy to treat osteosarcoma.…”

AdipoRon and Other Adiponectin Receptor Agonists as Potential Candidates in Cancer Treatments

“…Therefore, in the wake of the promising AdipoRon results, we recently decided to investigate its possible consequences in this bone-related tumor. In order to support an understanding and correct reading of the data, in this section we briefly summarized the main findings and tests performed in our latest publication [ 61 ].…”

“…U2OS ( d ), Saos-2 ( e ) and MG-63 ( f ) were grown in presence and absence of 20 μg/mL AdipoRon for 48 h and then compared for cell phase distribution by FACS analysis. Data reported in the figure above have already been published [ 61 ].…”

Treatment with sera from Water Polo athletes activates AMPKα and ACC proteins In HepG2 hepatoma cell line

“…Briefly, × 10 6 Hep G2 cells were seeded in 96-well plates and incubated with:-5% sera from-Water polo athletes,-basket amatorial players,-obese subjects, and-healthy controls. After 24, 48, and 72 h of incubation, cells were stained with MTT solution (3-[4,5-dimethylthiazol-2-yl]-2,5-dipheniltetrazolium-bromide/PBS) as previously reported [29]. All data are presented as mean ± SE of three independent experiments.…”