Interaction of Adipose-Derived Stromal Cells with Breast Cancer Cell Lines:

IGFBP3 enhances adipose-derived stem cell function in soft tissue injury repair via ITGB1 and ERK pathway activation

Soft tissue injury (STI) is a prevalent condition that requires effective therapeutic approaches. The focus of this investigation was to elucidate the molecular mechanisms linked to the IGFBP3 protein in adipose-derived stem cells (ADSCs) for STI repair, utilizing single-cell multiomics technology and a 3D bioprinting model. Establishment of a mouse-based STI model facilitated the comparison of cellular compositions and communication variances between wounded and normal tissues through single-cell RNA sequencing (scRNA-seq). High-throughput transcriptomics and bioinformatics analysis pinpointed IGFBP3 as a key target in ADSCs related to STI repair. In vitro experiments assessed IGFBP3's effects on ADSCs' epithelial cell differentiation, proliferation, and migration using various assays and lentivirus transfection to manipulate IGFBP3 expression. A 3D bioprinting technique was used to create an ADSCs-IGFBP3 peptide self-assembling hydrogel scaffold, characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, SEM, and TEM. The scaffold's efficacy was validated in an animal model. Results showed nine cell subtypes in both normal and injured tissues, with increased ADSCs in STI tissues exhibiting enhanced connectivity and interactions. RNA-seq analysis confirmed IGFBP3 as crucial for ADSCs and STI. In vitro and 3D bioprinting experiments, along with animal model validation, confirmed IGFBP3's role in STI repair. Upregulation of IGFBP3 in ADSCs promoted epithelial cell differentiation by enhancing ITGB1 expression, activating the ERK pathway to boost cell proliferation and migration. This study highlights IGFBP3's significant role in ADSCs for STI repair, providing potential molecular targets for developing new treatments. The findings offer valuable insights into IGFBP3's mechanisms, aiding in advancing STI therapeutic strategies.

Markers for the angiogenic potential of fat grafts

BACKGROUND

Fat grafting is widely utilized in reconstructive and esthetic plastic surgery, typically with minimal complications. Nevertheless, the occurrence of fat necrosis is dependent on the technique used for fat extraction, tissue processing and the volume of the graft. The longevity of the graft critically depends on the presence of adipose-derived stromal cells (ADSC) and their promotion of a reconstituted vascular supply.

OBJECTIVE

This study seeks to determine whether there are differences in 13 angiogenesis-related adipokines based on their grouping by vascular endothelial growth factor (VEGF) expression levels.

METHODS

The expression of 14 adipokines related to angiogenesis in 12 cultured ADSCs was evaluated using Human Adipokine Profiler kits, which simultaneously detect 58 mediators. Adipokines of the high and low VEGF expression groups were evaluated for their expression of the remaining 13 angiogenic proteins.

RESULTS

We were able to show that there are significant differences in VEGFlow and VEGFhigh ADSCs regarding fibroblast growth factor 19 (p = 0.043) and insulin like growth factor binding protein 3 (p = 0.028). Furthermore, ADSCs with differentially highly expressed VEGF show a different pattern in the amount of protein levels regarding the 13 other adipokines observed.

CONCLUSION

The VEGF has been described as a key angiogenic factor in fat grafts that may be linked to successful grafting; however, two of the fat samples analyzed exhibited high expression of VEGF but lacked significant co-expression of a range of other angiogenic factors. Thus, the assessment of the expression of predisposing mediators for graft angiogenesis for wound healing or contouring should include further angiogenesis promoters aside VEGF as parameters.

Vascular Endothelial Growth Factor Expression of Adipose-Derived Stromal Cells and Adipocytes Initiated from Fat Aspirations

BACKGROUND

Fat grafting is frequently employed in aesthetic and reconstructive plastic surgery with a low complication rate. However, fat necrosis may occur in dependence of the mode of fat aspiration, processing of the tissue and graft size. Graft survival is critically dependent on the contained adipose-derived stromal cells (ADSCs), adipocyte precursors and their potential for vascular supply. This work investigated the potential role of the expression of vascular endothelial growth factor A (VEGF) and various cytokines by ADSCs and differentiated adipocytes as key factors of fat grafting.

METHODS

Adipokine expression of ADSCs and differentiated adipocytes were assessed using Proteome Profiler Arrays that detect 58 relevant proteins.

RESULTS

Collected fat grafts could be categorized according to their adipokine expression into VEGFhigh and VEGFlow ADSCs groups, the former exhibiting higher content of VEGF-related angiopoietin-like 2, nidogen-1/entactin, CCL2/MCP-1 and elevated expression of IGFBPs in association with a fourfold higher VEGF expression. Differentiation of ADSCs into adipocytes increased VEGF concentrations in VEGFlow ADSCs but not in ADSCs exhibiting initial high VEGF concentrations. The adipocytes revealed high expression of HGF, leptin, CCL2/MCP-1, nidogen-1/entactin, M-CSF but lower induction of angiopoietin-like 2.

CONCLUSION

Half of the ADSCs from fat grafts express high concentrations of VEGF and other adipokines that support angiogenesis and survival of this tissues following transfer. Differentiation of ADSClow cells to adipocytes may make up for the initially low VEGF expression, but this activation is 7-10 days delayed compared to the VEGFhigh ADSC cells and may fail to support angiogenesis from the beginning.

NO LEVEL ASSIGNED

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Effects of metformin on human bone-derived mesenchymal stromal cell-breast cancer cell line interactions

Metformin is used to treat patients with type 2 diabetes mellitus and was found to lower the incidence of cancer. Bone metastasis is a common impairment associated with advanced breast cancer. The present study investigated the effects of metformin on human bone-derived mesenchymal stromal cells (BM-MSC)—breast cancer cell line interactions. BM-MSCs grown from box chisels were tested for growth-stimulating and migration-controlling activity on four breast cancer cell lines either untreated or after pretreatment with metformin. Growth stimulation was tested in MTT tests and migration in scratch assays. Furthermore, the expression of adipokines of BM-MSCs in response to metformin was assessed using Western blot arrays. Compared to breast cancer cell lines (3.6 ± 1.4% reduction of proliferation), 500 µM metformin significantly inhibited the proliferation of BM-MSC lines (mean 12.3 ± 2.2 reduction). Pretreatment of BM-MSCs with metformin showed variable effects of the resulting conditioned media (CM) on breast cancer cell lines depending on the specific BM-MSC—cancer line combination. Metformin significantly reduced the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in response to CM of drug-pretreated BM-MSCs. Assessment of metformin-induced alterations in the expression of adipokines by BM-MSC CM indicated increased osteogenic signaling and possibly impairment of metastasis. In conclusion, the anticancer activities of metformin are the result of a range of direct and indirect mechanisms that lower tumor proliferation and progression. A lower metformin-induced protumor activity of BM-MSCs in the bone microenvironment seem to contribute to the positive effects of the drug in selected breast cancer patients.

Interactions of BRCA1-mutated Breast Cancer Cell Lines with Adipose-derived Stromal Cells (ADSCs)

Lipofilling may constitute a technique to assist reconstruction of breasts following prophylactic mastectomy for patients with mutated BRCA1 or BRCA2 genes. However, to date it is not clear whether adipose-derived stromal cells (ADSCs) increase the risk of tumor initiation and progression in this situation. Therefore, the interactions of BRCA1 mutated breast cancer cell lines with normal ADSCs were investigated in the present study. Characteristics of MDA-MB-436 (BRCA1 c.5277 + 1G > A) and HCC1937 (BRCA1 p.Gln1756.Profs*74) were compared to MDA-MB-231 and T47D BRCA1/2 wild-type breast cancer cell lines. ADSCs were cultivated from lipoaspirates of a panel of BRCA1/2- wildtype patients. Interactions of conditioned medium (CM) of these cells with the breast cancer lines were studied using proliferation and migration assays as well as adipokine expression western blot arrays. CM of ADSCs exhibit a dose-dependent stimulation of the proliferation of the breast cancer cell lines. However, of the ADSC preparations tested, only 1 out of 18 samples showed a significant higher stimulation of BRCA1-mutated MDA-MB-436 versus wildtype MDA-MB-231 cells, and all CM revealed lower stimulatory activity for BRCA1-mutated HCC1937 versus wildtype T47D cells. Additionally, migration of breast cancer cells in response to CM of ADSCs proved to be equivalent or slower for BRCA1/2 mutated versus nonmutated cancer cells and, with exception of angiopoietin-like 2, induced expression of adipokines showed no major difference. Effects of media conditioned by normal ADSCs showed largely comparable effects on BRCA1-mutated and wildtype breast cancer cell lines thus advocating lipofilling, preferentially employing allogeneic non-mutated ADSCs.

Adipose-derived stromal/stem cells and extracellular vesicles for cancer therapy

INTRODUCTION

Mesenchymal stromal/stem cells (MSCs) hold great perspective for the therapy of a host of diseases due to regenerative and anti-inflammatory properties by differentiation into diverse cell populations, homing to damaged tissue regions, paracrine effects, and release of extracellular vesicles.

AREAS COVERED

This review describes the isolation, characterization, and potential use of MSCs and ADSCs for benign and malignant diseases. The MSCs may be administered as whole cells or in form of their secretome that is held responsible for most of their beneficial effects. A special constituent of the paracrine components are the extracellular vesicles (EVs) that carry a biologically potent cargo of proteins, cytokines, and RNA.

EXPERT OPINION

The applications of MSCs and ADSCs are amply documented and have been investigated in preclinical models and many unregulated and a few controlled trials. Larger numbers of MSCs and ADSCs can be obtained for allogeneic transfer but imply difficulties including perseverance of the cells in vivo and possible differentiation into harmful cell types. MSC-derived cell-free preparations are easier to handle and manufacture for various applications. Especially, with the help of bioreactors, EVs can be obtained in excessive numbers and preloaded or charged with proteins, cytokines, and regulatory RNA specimen to treat inflammatory diseases and cancer.

miR-224-5p Carried by Human Umbilical Cord Mesenchymal Stem Cells-Derived Exosomes Regulates Autophagy in Breast Cancer Cells via HOXA5

Objective: In this study, we focused on the potential mechanism of miRNAs carried by human umbilical cord mesenchymal stem cells-derived exosomes (hUCMSCs-exo) in breast cancer (BC).

Methods: RT-qPCR was conducted for the expression of miR-224-5p and HOXA5 in tissues and cells. After co-culture of exosomes and MCF-7 or MDA-MB-231 cells, the cell proliferation was observed by MTT and cell colony formation assay, while apoptosis was measured by flow cytometry. In addition, the expression of HOXA5 and autophagy pathway-related proteins LC3-II, Beclin-1 and P62 was detected by western blotting. And immunofluorescence was applied for detection of LC3 spots. The binding of miR-224-5p to HOXA5 was verified by the luciferase reporter gene assay and RNA-binding protein immunoprecipitation assay. Finally, in vivo experiment was performed to investigate the effect of miR-224-5p on BC growth.

Results: MiR-224-5p was up-regulated and HOXA5 was down-regulated in BC tissues and cells. HOXA5 was confirmed to be the target gene of miR-224-5p. MiR-224-5p carried by hUCMSCs-exo was able to promote the proliferation and autophagy of BC cells, while inhibited apoptosis. Bases on xenograft models in nude mice, it was also revealed that miR-224-5p carried by hUCMSCs-exo could regulate autophagy and contribute to the occurrence and development of BC in vivo.

Conclusion: MiR-224-5p carried by hUCMSCs-exo can regulate autophagy via inhibition of HOXA5, thus affecting the proliferation and apoptosis of BC cells.

Exosomes From Adipose-Derived Stem Cells: The Emerging Roles and Applications in Tissue Regeneration of Plastic and Cosmetic Surgery

Adipose-derived stem cells (ASCs) are an important stem cell type separated from adipose tissue, with the properties of multilineage differentiation, easy availability, high proliferation potential, and self-renewal. Exosomes are novel frontiers of intercellular communication regulating the biological behaviors of cells, such as angiogenesis, immune modulation, proliferation, and migration. ASC-derived exosomes (ASC-exos) are important components released by ASCs paracrine, possessing multiple biological activities. Tissue regeneration requires coordinated “vital networks” of multiple growth factors, proteases, progenitors, and immune cells producing inflammatory cytokines. Recently, as cell-to-cell messengers, ASC-exos have received much attention for the fact that they are important paracrine mediators contributing to their suitability for tissue regeneration. ASC-exos, with distinct properties by encapsulating various types of bioactive cargoes, are endowed with great application potential in tissue regeneration, mechanically via the migration and proliferation of repair cells, facilitation of the neovascularization, and other specific functions in different tissues. Here, this article elucidated the research progress of ASC-exos about tissue regeneration in plastic and cosmetic surgery, including skin anti-aging therapy, dermatitis improvement, wound healing, scar removal, flap transplantation, bone tissue repair and regeneration, obesity prevention, fat grafting, breast cancer, and breast reconstruction. Deciphering the biological properties of ASC-exos will provide further insights for exploring novel therapeutic strategies of tissue regeneration in plastic and cosmetic surgery.

Effects of metformin on adipose-derived stromal cell (ADSC) - Breast cancer cell lines interaction

AIMS

Metformin is a clinical drug administered to patients to treat type 2 diabetes mellitus that was found to be associated with a lower risk of occurrence of cancer and cancer-related death. The present study investigated the effects of metformin on human adipose-derived stromal cells (ADSC) - breast cancer cell line interactions.

MAIN METHODS

ADSCs grown from lipoaspirates were tested for growth-stimulating and migration-controlling activity on breast cancer cell lines after pretreatment with metformin. Furthermore, secreted proteins of ADSCs, phosphorylation of intracellular proteins and the effect of metformin on adipocytic differentiation of ADSCs were assayed.

KEY FINDINGS

Compared to breast cancer cell lines (4.0 ± 3.5% reduction of proliferation), 2 mM metformin significantly inhibited the proliferation of ADSC lines (19.2 ± 8.4% reduction of proliferation). This effect on ADSCs seems to be mediated by altered phosphorylation of GSK-3, CREB and PRAS40. Furthermore, treatment with metformin abolished the induction of differentiation of three ADSC lines to adipocytes. 1 and 2 mM metformin significantly impaired the migration of breast cancer cell lines MDA-MB-231 and MDA-MB-436 in scratch assays.

SIGNIFICANCE

Metformin showed low direct inhibitory effects on breast cancer cell lines at physiological concentrations but exerted a significant retardation of the growth and the adipocytic differentiation of ADSCs. Thus, the anticancer activity of metformin in breast cancer at physiological drug concentrations seems to be mediated by an indirect mechanism that lowers the supportive activity of ADSCs.

Fat grafts enriched with adipose-derived stem cells

Autologous fat grafts are widely used in soft-tissue augmentation and reconstruction. To reduce the unpredictability of fat grafts and to improve their long-term survival, cell-assisted lipotransfer (CAL) was introduced. In this alternative method, autologous fat is mixed and grafted with stromal vascular fraction cells or adipose-derived stem/stromal cells (ASCs). In regenerative medicine, ASCs exhibit excellent therapeutic potential and are also simple to harvest. Although the efficacy of CAL has been demonstrated in experimental and clinical research, studies on its safety in terms of oncologic risk have reported inconclusive results. In order to establish CAL as a viable stem cell therapeutic approach, it will be necessary to demonstrate its oncologic safety in basic and clinical studies. Doing so could transform the paradigm of clinical strategy and practice for the treatment of a wide variety of diseases.