Type 2 diabetes is associated with numerous long-term complications. This study aims to investigate whether impaired function of tissue-resident multipotent cells play role in pathogenesis of allied complications. Adipose-tissue-derived mesenchymal stem cells (ASCs) derived from nondiabetic (nASCs) and diabetic (dASCs) donors were compared with regard to glucose metabolism, cell replication, apoptosis, and differentiation potential. The data evidenced that elevation of glucose reduces proliferative capacity of both dASCs and nASCs, but impacts dASCs more significantly. Incorporation of insulin enhanced cell replication especially in nASCs. dASCs show higher levels of cellular senescence and apoptosis than nASCs. Unlike nASCs, apoptosis is induced via intrinsic pathway in dASCs. Data also evidenced that high glucose concentrations cause prominent disparities in nASCs and dASCs in expression of genes involved in insulin resistance such as adiponectin and resistin. Some changes in gene expression were irreversible in dASCs when treated with insulin. Additionally, high glucose concentrations reduce osteogenic and chondrogenic potential of ASCs, but enhance adipogenic potential. These results indicate that in addition to involvement in insulin resistance, impaired function of mesenchymal stem cells that reside in adipose tissue as one of the major sources of adult stem cells might be responsible for complications related to diabetes type 2.

BackgroundFat grafting is used to restore breast defects after surgical resection of breast tumors. Supplementing fat grafts with adipose tissue-derived stromal/stem cells (ASCs) is proposed to improve the regenerative/restorative ability of the graft and retention. However, long term safety for ASC grafting in proximity of residual breast cancer cells is unknown. The objective of this study was to determine the impact of human ASCs derived from abdominal lipoaspirates of three donors, on a human breast cancer model that exhibits early metastasis.Methodology/Principal FindingsHuman MDA-MB-231 breast cancer cells represents “triple negative” breast cancer that exhibits early micrometastasis to multiple mouse organs [1]. Human ASCs were derived from abdominal adipose tissue from three healthy female donors. Indirect co-culture of MDA-MB-231 cells with ASCs, as well as direct co-culture demonstrated that ASCs had no effect on MDA-MB-231 growth. Indirect co-culture, and ASC conditioned medium (CM) stimulated migration of MDA-MB-231 cells. ASC/RFP cells from two donors co-injected with MDA-MB-231/GFP cells exhibited a donor effect for stimulation of primary tumor xenografts. Both ASC donors stimulated metastasis. ASC/RFP cells were viable, and integrated with MDA-MB-231/GFP cells in the tumor. Tumors from the co-injection group of one ASC donor exhibited elevated vimentin, matrix metalloproteinase-9 (MMP-9), IL-8, VEGF and microvessel density. The co-injection group exhibited visible metastases to the lung/liver and enlarged spleen not evident in mice injected with MDA-MB-231/GFP alone. Quantitation of the total area of GFP fluorescence and human chromosome 17 DNA in mouse organs, H&E stained paraffin sections and fluorescent microscopy confirmed multi-focal metastases to lung/liver/spleen in the co-injection group without evidence of ASC/RFP cells.ConclusionsHuman ASCs derived from abdominal lipoaspirates of two donors stimulated metastasis of MDA-MB-231 breast tumor xenografts to multiple mouse organs. MDA-MB-231 tumors co-injected with ASCs from one donor exhibited partial EMT, expression of MMP-9, and increased angiogenesis.

Src kinase is elevated in breast tumors that are ER/PR negative and do not overexpress HER2 but clinical trials with Src inhibitors have demonstrated little activity. The present study evaluated preclinical efficacy of a novel peptidomimetic compound, KX-01 (KX2-391), that exhibits dual action as a Src and pretubulin inhibitor. KX-01 was evaluated as a single agent and in combination with paclitaxel in MDA-MB-231, MDA-MB-157, and MDA-MB-468 human ER/PR/HER2-negative breast cancer cells. Treatments were evaluated by growth/apoptosis, isobologram analysis, migration/invasion assays, tumor xenograft volume, metastasis, and measurement of Src, FAK, microtubules, Ki67, and microvessel density. KX-01 inhibited cell growth in vitro and in combination with paclitaxel resulted in synergistic growth inhibition. KX-01 resulted in a dose dependent inhibition of MDA-MB-231 and MDA-MB-157 tumor xenografts (1 and 5 mg/kg, BID). KX-01 inhibited activity of Src and downstream mediator FAK in tumors that was coincident with reduced proliferation and angiogenesis, and increased apoptosis. KX01 also resulted in microtubule disruption in tumors. Combination of KX-01 with paclitaxel resulted in significant regression of MDA-MB-231 tumors and reduced metastasis to mouse lung and liver. KX-01 is a potently active Src/pretubulin inhibitor that inhibits breast tumor growth and metastasis. As ER/PR/HER2-negative patients are candidates for paclitaxel therapy, combination with KX-01 may potentiate antitumor efficacy in management of this aggressive breast cancer subtype.

Human ASCs did not alter growth of human head/neck cancer cells or tumor xenografts, but stimulated migration and early micrometastasis to mouse brain.