Breast cancer cells attract the migration of adipose tissue-derived stem cells via the PDGF-BB/PDGFR-beta signaling pathway

Identification and verification of AK4 as a protective immune-related biomarker in adipose-derived stem cells and breast cancer

Background

Breast cancer (BC) remains the most common cancer among women, and novel post-surgical reconstruction techniques, including autologous fat transplantation, have emerged. While Adipose-derived stem cells (ADSCs) are known to impact the viability of fat grafts, their influence on breast cancer progression remains unclear. This study aims to elucidate the genetic interplay between ADSCs and breast cancer, focusing on potential therapeutic targets.

Methods

Using the GEO and TCGA databases, we pinpointed differentially expressed (DE) mRNAs, miRNAs, lncRNAs, and pseudogenes of ADSCs and BC. We performed functional enrichment analysis and constructed protein-protein interaction (PPI), RNA binding protein (RBP)-pseudogene-mRNA, and lncRNA-miRNA-transcription factor (TF)-gene networks. Our study delved into the correlation of AK4 expression with 33 different malignancies and examined its impact on prognostic outcomes across a pan-cancer cohort. Additionally, we scrutinized immune infiltration, microsatellite instability, and tumor mutational burden, and conducted single-cell analysis to further understand the implications of AK4 expression. We identified novel sample subtypes based on hub genes using the ConsensusClusterPlus package and examined their association with immune infiltration. The random forest algorithm was used to screen DE mRNAs between subtypes to validate the powerful prognostic prediction ability of the artificial neural network.

Results

Our analysis identified 395 DE mRNAs, 3 DE miRNAs, 84 DE lncRNAs, and 26 DE pseudogenes associated with ADSCs and BC. Of these, 173 mRNAs were commonly regulated in both ADSCs and breast cancer, and 222 exhibited differential regulation. The PPI, RBP-pseudogene-mRNA, and lncRNA-miRNA-TF-gene networks suggested AK4 as a key regulator. Our findings support AK4 as a promising immune-related therapeutic target for a wide range of malignancies. We identified 14 characteristic genes based on the AK4-related cluster using the random forest algorithm. Our artificial neural network yielded excellent diagnostic performance in the testing cohort with AUC values of 0.994, 0.973, and 0.995, indicating its ability to distinguish between breast cancer and non-breast cancer cases.

Conclusions

Our research sheds light on the dual role of ADSCs in BC at the genetic level and identifies AK4 as a key protective mRNA in breast cancer. We found that AK4 significantly predicts cancer prognosis and immunotherapy, indicating its potential as a therapeutic target.

Non-Contrast-Enhanced Multiparametric MRI of the Hypoxic Tumor Microenvironment Allows Molecular Subtyping of Breast Cancer: A Pilot Study

Tumor neoangiogenesis is an important hallmark of cancer progression, triggered by alternating selective pressures from the hypoxic tumor microenvironment. Non-invasive, non-contrast-enhanced multiparametric MRI combining blood-oxygen-level-dependent (BOLD) MRI, which depicts blood oxygen saturation, and intravoxel-incoherent-motion (IVIM) MRI, which captures intravascular and extravascular diffusion, can provide insights into tumor oxygenation and neovascularization simultaneously. Our objective was to identify imaging markers that can predict hypoxia-induced angiogenesis and to validate our findings using multiplexed immunohistochemical analyses. We present an in vivo study involving 36 female athymic nude mice inoculated with luminal A, Her2+, and triple-negative breast cancer cells. We used a high-field 9.4-tesla MRI system for imaging and subsequently analyzed the tumors using multiplex immunohistochemistry for CD-31, PDGFR-β, and Hif1-α. We found that the hyperoxic-BOLD-MRI-derived parameter ΔR2* discriminated luminal A from Her2+ and triple-negative breast cancers, while the IVIM-derived parameter fIVIM discriminated luminal A and Her2+ from triple-negative breast cancers. A comprehensive analysis using principal-component analysis of both multiparametric MRI- and mpIHC-derived data highlighted the differences between triple-negative and luminal A breast cancers. We conclude that multiparametric MRI combining hyperoxic BOLD MRI and IVIM MRI, without the need for contrast agents, offers promising non-invasive markers for evaluating hypoxia-induced angiogenesis.

Improving Autologous Fat Grafting in Regenerative Surgery through Stem Cell-Assisted Lipotransfer

Autologous fat transplantation -i.e., lipofilling- has become a promising and popular technique in aesthetic and reconstructive surgery with several application such as breast reconstruction, facial and hand rejuvenation. However, the use of this technology is still limited due to an unpredictable and low graft survival rate (which ranges from 25%-80%). A systematic literature review was performed by thoroughly searching 12 terms using the PubMed database. The objective of this study is to present the current evidence for the efficacy of adjuvant regenerative strategies and cellular factors, which have been tested to improve fat graft retention. We present the main results (fat retention rate, histological analysis for pre-clinical studies and satisfaction/ complication for clinical studies) obtained from the studies of the three main fat grafting enrichment techniques: platelet-rich plasma (PRP), the stromal vascular fraction (SVF) and adipose-derived stem cells (ADSCs) and discuss the promising role of recent angiogenic cell enrichment that could induce early vascularization of fat graft. All in all, adding stem or progenitor cells to autologous fat transplantation might become a new concept in lipofilling. New preclinical models should be used to find mechanisms able to increase fat retention, assure safety and transfer these technologies to a good manufacturing practice (GMP) compliant facility, to manufacture an advanced therapy medicinal product (ATMP).

New insights about the PDGF/PDGFR signaling pathway as a promising target to develop cancer therapeutic strategies

Numerous cancers express platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs). By directly stimulating tumour cells in an autocrine manner or by stimulating tumour stromal cells in a paracrine manner, the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is crucial in the growth and spread of several cancers. To combat hypoxia in the tumour microenvironment, it encourages angiogenesis. A growing body of experimental data shows that PDGFs target malignant cells, vascular cells, and stromal cells to modulate tumour growth, metastasis, and the tumour microenvironment. To combat medication resistance and enhance patient outcomes in cancers, targeting the PDGF/PDGFR pathway is a viable therapeutic approach. There have been reports of anomalies in the PDGF pathway, including the gain of function point mutations, activating chromosomal translocations, or overexpression or amplification of PDGF receptors (PDGFRs). As a result, it has been shown that targeting the PDGF/PDGFR signaling pathway is an effective method for treating cancer. As a result, this study will concentrate on the regulation of the PDGF/PDGFR signaling system, in particular the current methods and inhibitors used in cancer treatment, as well as the associated therapeutic advantages and side effects.

The Role of Mesenchymal Stem Cells in Modulating the Breast Cancer Microenvironment

The role of mesenchymal stem cells (MSCs) in the breast tumor microenvironment (TME) is significant and multifaceted. MSCs are recruited to breast tumor sites through molecular signals released by tumor sites. Once in the TME, MSCs undergo polarization and interact with various cell populations, including immune cells, cancer-associated fibroblasts (CAFs), cancer stem cells (CSCs), and breast cancer cells. In most cases, MSCs play roles in breast cancer therapeutic resistance, but there is also evidence that indicates their abilities to sensitize cancer cells to chemotherapy and radiotherapy. MSCs possess inherent regenerative and homing properties, making them attractive candidates for cell-based therapies. Therefore, MSCs can be engineered to express therapeutic molecules or deliver anti-cancer agents directly to tumor sites. Unraveling the intricate relationship between MSCs and the breast TME has the potential to uncover novel therapeutic targets and advance our understanding of breast cancer biology.

Diverse roles of tumor-stromal PDGFB-to-PDGFRβ signaling in breast cancer growth and metastasis

Over the last couple of decades, it has become increasingly apparent that the tumor microenvironment (TME) mediates every step of cancer progression and solid tumors are only able to metastasize with a permissive TME. This intricate interaction of cancer cells with their surrounding TME, or stroma, is becoming more understood with an ever greater knowledge of tumor-stromal signaling pairs such as platelet-derived growth factors (PDGF) and their cognate receptors. We and others have focused our research efforts on understanding how tumor-derived PDGFB activates platelet-derived growth factor receptor beta (PDGFRβ) signaling specifically in the breast cancer TME. In this chapter, we broadly discuss PDGF and PDGFR expression patterns and signaling in normal physiology and breast cancer. We then detail the expansive roles played by the PDGFB-to-PDGFRβ signaling pathway in modulating breast tumor growth and metastasis with a focus on specific cellular populations within the TME, which are responsive to tumor-derived PDGFB. Given the increasingly appreciated importance of PDGFB-to-PDGFRβ signaling in breast cancer progression, specifically in promoting metastasis, we end by discussing how therapeutic targeting of PDGFB-to-PDGFRβ signaling holds great promise for improving current breast cancer treatment strategies.

The Impact of Obesity, Adipose Tissue, and Tumor Microenvironment on Macrophage Polarization and Metastasis

Tumor metastasis is a major cause of death in cancer patients. It involves not only the intrinsic alterations within tumor cells, but also crosstalk between these cells and components of the tumor microenvironment (TME). Tumorigenesis is a complex and dynamic process, involving the following three main stages: initiation, progression, and metastasis. The transition between these stages depends on the changes within the extracellular matrix (ECM), in which tumor and stromal cells reside. This matrix, under the effect of growth factors, cytokines, and adipokines, can be morphologically altered, degraded, or reorganized. Many cancers evolve to form an immunosuppressive TME locally and create a pre-metastatic niche in other tissue sites. TME and pre-metastatic niches include myofibroblasts, immuno-inflammatory cells (macrophages), adipocytes, blood, and lymphatic vascular networks. Several studies have highlighted the adipocyte-macrophage interaction as a key driver of cancer progression and dissemination. The following two main classes of macrophages are distinguished: M1 (pro-inflammatory/anti-tumor) and M2 (anti-inflammatory/pro-tumor). These cells exhibit distinct microenvironment-dependent phenotypes that can promote or inhibit metastasis. On the other hand, obesity in cancer patients has been linked to a poor prognosis. In this regard, tumor-associated adipocytes modulate TME through the secretion of inflammatory mediators, which modulate and recruit tumor-associated macrophages (TAM). Hereby, this review describes the cellular and molecular mechanisms that link inflammation, obesity, and cancer. It provides a comprehensive overview of adipocytes and macrophages in the ECM as they control cancer initiation, progression, and invasion. In addition, it addresses the mechanisms of tumor anchoring and recruitment for M1, M2, and TAM macrophages, specifically highlighting their origin, classification, polarization, and regulatory networks, as well as their roles in the regulation of angiogenesis, invasion, metastasis, and immunosuppression, specifically highlighting the role of adipocytes in this process.

Effects of Cell Density and Microenvironment on Stem Cell Mitochondria Transfer among Human Adipose-Derived Stem Cells and HEK293 Tumorigenic Cells

Stem cells (SC) are largely known for their potential to restore damaged tissue through various known mechanisms. Among these mechanisms is their ability to transfer healthy mitochondria to injured cells to rescue them. This mitochondrial transfer plays a critical role in the healing process. To determine the optimal parameters for inducing mitochondrial transfer between cells, we assessed mitochondrial transfer as a function of seeding density and in two-dimensional (2D) and semi three-dimensional (2.5D) culture models. Since mitochondrial transfer can occur through direct contact or secretion, the 2.5D culture model utilizes collagen to provide cells with a more physiologically relevant extracellular matrix and offers a more realistic representation of cell attachment and movement. Results demonstrate the dependence of mitochondrial transfer on cell density and the distance between donor and recipient cell. Furthermore, the differences found between the transfer of mitochondria in 2D and 2.5D microenvironments suggest an optimal mode of mitochondria transport. Using these parameters, we explored the effects on mitochondrial transfer between SCs and tumorigenic cells. HEK293 (HEK) is an immortalized cell line derived from human embryonic kidney cells which grow rapidly and form tumors in culture. Consequently, HEKs have been deemed tumorigenic and are widely used in cancer research. We observed mitochondrial transfer from SCs to HEK cells at significantly higher transfer rates when compared to a SC–SC co-culture system. Interestingly, our results also revealed an increase in the migratory ability of HEK cells when cultured with SCs. As more researchers find co-localization of stem cells and tumors in the human body, these results could be used to better understand their biological relationship and lead to enhanced therapeutic applications.

OUP accepted manuscript

Adipose-derived stem or stromal cells (ASCs) possess promising potential in the fields of tissue engineering and regenerative medicine due to their secretory activity, their multilineage differentiation potential, their easy harvest, and their rich yield compared to other stem cell sources. After the first identification of ASCs in humans in 2001, the knowledge of their cell biology and cell characteristics have advanced, and respective therapeutic options were determined. Nowadays, ASC-based therapies are on the verge of translation into clinical practice. However, conflicting evidence emerged in recent years about the safety profile of ASC applications as they may induce tumor progression and invasion. Numerous in-vitro and in-vivo studies demonstrate a potential pro-oncogenic effect of ASCs on various cancer entities. This raises questions about the safety profile of ASCs and their broad handling and administration. However, these findings spark controversy as in clinical studies ASC application did not elevate tumor incidence rates, and other experimental studies reported an inhibitory effect of ASCs on different cancer cell types. This comprehensive review aims at providing up-to-date information about ASCs and cancer cell interactions, and their potential carcinogenesis and tumor tropism. The extracellular signaling activity of ASCs, the interaction of ASCs with the tumor microenvironment, and 3 major organ systems (the breast, the skin, and genitourinary system) will be presented with regard to cancer formation and progression.

Perspective: Why and How Ubiquitously Distributed, Vascular-Associated, Pluripotent Stem Cells in the Adult Body (vaPS Cells) Are the Next Generation of Medicine

A certain cell type can be isolated from different organs in the adult body that can differentiate into ectoderm, mesoderm, and endoderm, providing significant support for the existence of a certain type of small, vascular-associated, pluripotent stem cell ubiquitously distributed in all organs in the adult body (vaPS cells). These vaPS cells fundamentally differ from embryonic stem cells and induced pluripotent stem cells in that the latter possess the necessary genetic guidance that makes them intrinsically pluripotent. In contrast, vaPS cells do not have this intrinsic genetic guidance, but are able to differentiate into somatic cells of all three lineages under guidance of the microenvironment they are located in, independent from the original tissue or organ where they had resided. These vaPS cells are of high relevance for clinical application because they are contained in unmodified, autologous, adipose-derived regenerative cells (UA-ADRCs). The latter can be obtained from and re-applied to the same patient at the point of care, without the need for further processing, manipulation, and culturing. These findings as well as various clinical examples presented in this paper demonstrate the potential of UA-ADRCs for enabling an entirely new generation of medicine for the benefit of patients and healthcare systems.

Impact of human adipose tissue-derived stem cells on dermatofibrosarcoma protuberans cells in an indirect co-culture: an in vitro study

BACKGROUND

Autologous adipose tissue transfer may be performed for aesthetic needs following the resection of dermatofibrosarcoma protuberans (DFSP), the most common cutaneous soft tissue sarcoma, excluding Kaposi sarcoma. The regenerative effectiveness of cell-assisted lipotransfer is dependent on the presence of adipose tissue-derived stem cells (ADSCs). This is the first study to evaluate the potential oncological risks as ADSCs could unintentionally be sited within the proximity of the tumor microenvironment of DFSP cells.

METHODS

Primary DFSP cells were indirectly co-cultured with ADSCs in a conditioned medium or in a Transwell system. The impact was analyzed by assessing proliferation, migration, invasion, angiogenesis, and tumor-associated genes and proteins. Results of these assays were compared between co-culture and mono-culture conditions.

RESULTS

Our experimental results showed that ADSCs were able to promote proliferation, migration, invasion, and angiogenesis of DFSP cells; this was accompanied by a significant increase in the expression levels of beta-type platelet-derived growth factor receptor, collagen type I alpha 1 chain, vascular endothelial growth factor, hepatocyte growth factor, and basic fibroblast growth factor.

CONCLUSIONS

The current report clearly demonstrates that ADSCs can enhance different malignant properties of DFSP cells in vitro, which should not be neglected when considering the clinical use of human ADSCs and its related derivatives in skin regenerative therapies.

Autologous Fat Grafting for Oncologic Patients: A Literature Review

Autologous fat grafting (AFG) serves as an effective method to address volume defects, contour irregularities, and asymmetry in both aesthetic and reconstructive procedures. In recent years, there has been growing concern about the potential of cancer recurrence and interference with cancer surveillance in oncologic patients receiving AFG. The adipose tissue contains adipose-derived stem cells (ASCs), a specific type of mesenchymal stem cells, that facilitate secretion of numerous growth factors which in turn stimulate tissue regeneration and angiogenesis. As such, it has been theorized that ASCs may also have the potential to stimulate cancer cell proliferation and growth when used in oncologic patients. Multiple research studies have demonstrated the ability of ACSs to facilitate tumor proliferation in animal models. However, clinical research in oncologic patients has yielded contradictory findings. Although the literature pertaining to oncologic safety in head and neck, as well as sarcoma, cancer patients remains limited, studies demonstrate no increased risk of tumor recurrence in these patient populations receiving AFG. Similarly, both the efficacy and safety of AFG have been well established in breast cancer patients through numerous clinical studies. More recently, preclinical research in animal models has shown that AFG has the potential to facilitate tissue regeneration and improve joint contracture following irradiation. Ultimately, further research is needed to elucidate the safety of AFG in a variety of oncologic patients, as well as explore its use in tissue regeneration, particularly in the setting of radiotherapy. Level of Evidence: 4.

Serum Platelet-Derived Growth Factor Is Significantly Lower in Patients with Lung Cancer and Continued to Decrease After Platinum-Based Chemotherapy

Objective

This study aimed to investigate the diagnosis and prediction of serum platelet-derived growth factor (PDGF) level in patients with lung cancer (LC).

Methods

Serum concentrations of PDGF-AA and PDGF-AB/BB were determined via Luminex assay in 210 patients with non-small cell lung cancer (NSCLC), 33 patients with small cell lung cancer (SCLC), and 168 healthy controls.

Results

The serum levels of PDGF-AA and PDGF-AB/BB were lower in patients with NSCLC (P < 0.05) and SCLC (P < 0.05), compared to healthy controls. The concentration of PDGF-AA or PDGF-AB/BB continued to markedly decrease in NSCLC after therapy with platinum-based chemotherapy (P < 0.05). The median survival times were 29 and 38 months in patients with NSCLC who received PDGF-AA < 30 ng/mL and PDGF-AA ≥ 30 ng/mL (P = 0.0078), and 26 and 38 months in patients with NSCLC who received PDGF-AB/BB < 42 ng/mL and PDGF-AB/BB ≥ 42 ng/mL (P = 0.0001), respectively. At the individual protein level, PDGF-AA and PDGF-AB/BB had better diagnostic values for NSCLC (AUC = 0.905, AUC = 0.922, respectively).

Conclusion

Serum PDGF may be a potential biomarker for diagnosis of patients with NSCLC and SCLC. However, the prognostic value of serum PDGF in patients with NSCLC harboring mutations and different therapies requires additional investigation.

Multifaceted Oncogenic Role of Adipocytes in the Tumour Microenvironment

Obesity has for decades been recognised as one of the major health concerns. Recently accumulated evidence has established that obesity or being overweight is strongly linked to an increased risk of cancer. However, it is still not completely clear how adipose tissue (fat), along with other stromal connective tissues and cells, contribute to tumour initiation and progression. In the tumour microenvironment, the adipose tissue cells, in particular the adipocytes, secrete a number of adipokines, including growth factors, hormones, collagens, fatty acids, and other metabolites as well as extracellular vesicles to shape and condition the tumour and its microenvironment. In fact, the adipocytes, through releasing these factors and materials, can directly and indirectly facilitate cancer cell proliferation, apoptosis, metabolism, angiogenesis, metastasis and even chemotherapy resistance. In this chapter, the multidimensional role played by adipocytes, a major and functional component of the adipose tissue, in promoting cancer development and progression within the tumour microenvironment will be discussed.

Visfatin Mediates Malignant Behaviors through Adipose-Derived Stem Cells Intermediary in Breast Cancer

Adipose-derived stem cells (ADSCs) have been implicated in tumor growth and metastasis in breast cancer. ADSCs exhibit tumor tropism, and are of increasing clinical relevance due to the autologous fat grafting for breast reconstruction. Although we have previously shown that a high level of the adipocytokine visfatin in human breast cancer tissues correlated with tumor progression mediated by cAbl and STAT3, the effects of visfatin in the tumor microenvironment are unclear. To understand how visfatin modulates breast cancer within the tumor-stromal environment, we examined determinants of breast cancer progression using a visfatin-primed ADSCs-tumor co-culture model. ADSCs were isolated from tumor-free adipose tissue adjacent to breast tumors. ADSCs were treated with or without visfatin for 48 h and then collected for co-culture with breast cancer cell line MDA-MB-231 for 72 h in a transwell system. We found that the MDA-MB-231 cells co-cultured with visfatin-treated ADSCs (vADSCs) had higher levels of cell viability, anchorage independent growth, migration, invasion, and tumorsphere formation than that co-cultured with untreated ADSCs (uADSCs). Growth differentiation factor 15 (GDF15) upregulation was found in the co-culture conditioned medium, with GDF15 neutralizing antibody blocking the promoting effect on MDA-MB-231 in co-culture. In addition, a GDF15-induced AKT pathway was found in MDA-MB-231 and treatment with PI3K/AKT inhibitor also reversed the promoting effect. In an orthotopic xenograft mouse model, MDA-MB-231 co-injected with vADSCs formed a larger tumor mass than with uADSCs. Positive correlations were noted between visfatin, GDF15, and phosphor-AKT expressions in human breast cancer specimens. In conclusion, visfatin activated GDF15-AKT pathway mediated via ADSCs to facilitate breast cancer progression.

ETS variant 5 promotes colorectal cancer angiogenesis by targeting platelet-derived growth factor BB

ETS transcription factors play important roles in tumor cell invasion, differentiation and angiogenesis. In this study, we initially demonstrated that ETS translocation variant 5 (ETV5) is abnormally upregulated in colorectal cancer (CRC), is positively correlated with CRC tumor size, lymphatic metastasis and tumor node metastasis (TNM) stage and indicates shorter survival and disease-free survival in CRC patients. In vitro and in vivo experiments revealed that the downregulation of ETV5 could significantly suppress CRC cell proliferation. Moreover, overexpression of ETV5 could stimulate CRC angiogenesis in vitro and in vivo, which is consistent with RNA-seq results. Then, we identified platelet-derived growth factor BB (PDGF-BB) as a direct target of ETV5 that plays an important role in ETV5-mediated CRC angiogenesis through an angiogenesis antibody microarray. Additionally, PDGF-BB could activate VEGFA expression via the PDGFR-β/Src/STAT3 pathway in CRC cells and appeared to be positively correlated with ETV5 in CRC tissues. Finally, we revealed that ETV5 could bind directly to the promoter region of PDGF-BB and regulate its expression through ChIP and luciferase assays. Overall, our study suggested that the transcription factor ETV5 could stimulate CRC malignancy and promote CRC angiogenesis by directly targeting PDGF-BB. These findings suggest that EVT5 may be a potential new diagnostic and prognostic marker in CRC and that targeting ETV5 might be a potential therapeutic option for inhibiting CRC angiogenesis.

PDGF regulated migration of mesenchymal stem cells towards malignancy acts via the PI3K signaling pathway

INTRODUCTION

Mesenchymal stem cells (MSCs) have been described in breast cancer models to migrate towards carcinoma and integrate into tumor associated stroma supporting tumor growth, increasing their metastatic potency and contributing to tumor-angiogenesis. Platelet-derived growth factor (PDGF) isoforms (AA, BB, CC) stimulate growth, survival and motility of MSCs and certain other cell types. Noteworthy, breast carcinomas are known to express PDGF. We aim to further shed light on i) the relevance of the different PDGF isoforms on adipose tissue derived stem cells (ASCs) migration and ii) the underlying pathway dependent on PDGF stimulation.

MATERIALS AND METHODS

Breast cancer cell lines were purchased and ASC's were isolated from murine subcutaneous adipose tissue. The transmigration of ASC's towards the PDGF-isoforms was assessed by using recombinant human PDGF-AA, PDGF-BB and PDGF-CC in a trans-well culture dish system. Transmigrated ASC's were quantified in 5 randomly selected fields per condition using fluorescence microscopy after calcein-staining. PDGF-BB depended transmigration of ASC's was verified by downregulation and overexpression of PDGF-BB in breast cancer cell line using lentiviral vectors. In addition, a PI3-kinase inhibitor (LY294002) and a MAP-kinase inhibitor (PD98059) were used to identify the pathway involved in the PDGF-BB mediated migration of ASC's towards tumor.

RESULTS

ASC's transmigration significantly increased towards PDGF AA at 50 ng and only showed further increase by 500 ng which was similar to cell behavior when exposed to PDGF CC. In comparison, PDGF-BB significantly increased ASC's transmigration already at a low level of 5 ng with further significant increase for 20 ng and 40 ng. Cell transmigration was blocked with PDGFR-α antibodies but only for PDGF-AA and PDGF-CC whereas PDGFR-β blockage showed a significant effect on transmigration for PDGF-BB and PDGF-CC but not for PDGF-AA. Neutralizing antibodies in combination with PDGF receptor blockage confirmed findings. In addition, only PI3-kinase inhibitor but not the MEK-1 selective inhibitor caused a significant decrease of transmigration for ASCs towards breast cancer cells.

DISCUSSION

The transmigration of ASC's is most significantly enhanced by PDGF-BB via the PI3-kinase pathway. This data support that PI3-kinase is an important key player for MSC migration towards malignancy which need further research to prevent tumor progression in early disease stage.

Making Sense of Stem Cells and Fat Grafting in Plastic Surgery: The Hype, Evidence, and Evolving U.S. Food and Drug Administration Regulations

Autologous fat grafting and adipose-derived stem cells are two distinct entities with two different risk profiles, and should be regulated as such. Autologous fat grafting prepared with the additional step of stromal vascular fraction isolation is considered a form of "stem cell therapy" given the high concentration of stem cells found in stromal vascular fraction. Much ambiguity existed in the distinction between autologous fat grafting and stromal vascular fraction initially, in terms of both their biological properties and how they should be regulated. The market has capitalized on this in the past decade to sell unproven "stem cell" therapies to unknowing consumers while exploiting the regulatory liberties of traditional fat grafting. This led to a Draft Guidance from the U.S. Food and Drug Administration in 2014 proposing stricter regulations on fat grafting in general, which in turn elicited a response from plastic surgeons, who have safely used autologous fat grafting in the clinical setting for over a century. After a series of discussions, the U.S. Food and Drug Administration released its Final Guidance in November of 2017, which established clear distinctions between autologous fat grafting and stromal vascular fraction and their separate regulations. By educating ourselves on the U.S. Food and Drug Administration's final stance on fat grafting and stem cell therapy, we can learn how to navigate the regulatory waters for the two entities and implement their clinical use in a responsible and informed manner.

Application of a novel targeting nanoparticle contrast agent combined with magnetic resonance imaging in the diagnosis of intraductal papillary mucinous neoplasm

Intraductal papillary mucinous neoplasm (IPMN) is a severe disease with macroscopic visible mucin secretion that primarily occurs in biliary tracts or pancreatic ducts. In comparison with standard diagnostic imaging, probing the molecular abnormalities associated with the initial stages of diseases rather than imaging the end effects markedly improves the accuracy of diagnosis. In the present study, magnetic resonance imaging (MRI) in combination with the contrast agent PEGylated magnetoliposome consisting of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) and target molecules of IPMN were investigated in the diagnosis of patients with suspected IPMN. The present investigation indicated that the novel targeting nanoparticle contrast agent targeted platelet-derived growth factor receptor-β and RET, and maintained a high affinity with tumor markers located on the IPMN surface. The novel targeting nanoparticle contrast agent combined with MRI exhibited increased sensitivity in diagnosing early-stage patients with IPMN. Furthermore, image quality was improved following the use of the novel targeting nanoparticle contrast agent combined with MRI compared with standard MRI. The targeting nanoparticle contrast agent retained sufficient affinity and was present for an adequate amount of time to observe the tumor mass in papillae using MRI. Notably, the targeting nanoparticle contrast agent was metabolized at 12 h post-injection. In conclusion, these outcomes indicate that the novel targeting nanoparticle contrast agent combined with MRI improved image quality and sensitivity compared with standard MRI, which suggests that this approach may be promising for clinical detection in patients with suspected IPMN.

TRAF3IP2, a novel therapeutic target in glioblastoma multiforme

Glioblastoma multiforme (glioblastoma) remains one of the deadliest cancers. Pro-inflammatory and pro-tumorigenic mediators present in tumor microenvironment (TME) facilitate communication between tumor cells and adjacent non-malignant cells, resulting in glioblastoma growth. Since a majority of these mediators are products of NF-κB- and/or AP-1-responsive genes, and as TRAF3 Interacting Protein 2 (TRAF3IP2) is an upstream regulator of both transcription factors, we hypothesized that targeting TRAF3IP2 blunts tumor growth by inhibiting NF-κB and pro-inflammatory/pro-tumorigenic mediators. Our in vitro data demonstrate that similar to primary glioblastoma tumor tissues, malignant glioblastoma cell lines (U87 and U118) express high levels of TRAF3IP2. Silencing TRAF3IP2 expression inhibits basal and inducible NF-κB activation, induction of pro-inflammatory mediators, clusters of genes involved in cell cycle progression and angiogenesis, and formation of spheroids. Additionally, silencing TRAF3IP2 significantly increases apoptosis. In vivo studies indicate TRAF3IP2-silenced U87 cells formed smaller tumors. Additionally, treating existing tumors formed by wild type U87 cells with lentiviral TRAF3IP2 shRNA markedly regresses their size. Analysis of residual tumors revealed reduced expression of pro-inflammatory/pro-tumorigenic/pro-angiogenic mediators and kinesins. In contrast, the expression of IL-10, an anti-inflammatory cytokine, was increased. Together, these novel data indicate that TRAF3IP2 is a master regulator of malignant signaling in glioblastoma, and its targeting modulates the TME and inhibits tumor growth by suppressing the expression of mediators involved in inflammation, angiogenesis, growth, and malignant transformation. Our data identify TRAF3IP2 as a potential therapeutic target in glioblastoma growth and dissemination.

CD140b (PDGFRβ) signaling in adipose-derived stem cells mediates angiogenic behavior of retinal endothelial cells

Adipose-derived stem cells (ASCs) are multipotent mesenchymal progenitor cells that have functional and phenotypic overlap with pericytes lining microvessels in adipose tissue. The role of CD140b [platelet-derived growth factor receptor- β (PDGFR-β)], a constitutive marker expressed by ASCs, in the angiogenic behavior of human retinal endothelial cells (HREs) is not known. CD140b was knocked down in ASCs using targeted siRNA and lipofectamine transfection protocol. Both CD140b+ and CD140b- ASCs were tested for their proliferation (WST-1 reagent), adhesion (laminin-1 coated plates), and migration (wound-scratch assay). Angiogenic effect of CD140b+ and CD140b- ASCs on HREs was examined by co-culturing ASCs:HREs in 12:1 ratio for 6 days followed by visualization of vascular network by Isolectin B4 staining. The RayBio® Membrane-Based Antibody Array was used to assess differences in human cytokines released by CD140b+ or CD140b- ASCs. Knockdown of CD140b in ASCs resulted in a significant 50% decrease in proliferation rate, 25% decrease in adhesion ability to Laminin-1, and 50% decrease in migration rate, as compared to CD140b+ ASCs. Direct contact of ASCs expressing CD140b+ with HREs resulted in robust vascular network formation that was significantly reduced with using CD140b- ASCs. Of the 80 proteins tested, 45 proteins remained unchanged (>0.5-<1.5 fold), 6 proteins including IL-10 downregulated (<0.5 fold) and 29 proteins including IL-16 & TNF-β were upregulated (>1.5 fold) in CD140b- ASCs compared to CD140b+ ASCs. Our data demonstrate a substantial role for CD140b in the intrinsic abilities of ASCs and their angiogenic influence on HREs. Future studies are needed to fully explore the signaling of CD140b in ASCs in vivo for retinal regeneration.

Role of extracellular vesicles in glioma progression

The role of extracellular vesicles in cancer biology has emerged as a focus of the study of great importance and has been shown to directly influence tumour development in several cancers including brain tumours, such as gliomas. Gliomas are the most aggressive brain tumours, and in the last time, a considerable effort has been made to understand their biology. Studies focus in the signalling pathways involved in the processes of angiogenesis, viability, drug resistance and immune response evasion, as well as gliomas ability to infiltrate healthy tissue, a phenomenon regulated by the migratory and invasive capacity of the cells within a tumour. In this review, we summarize the different types and classifications of extracellular vesicles, their intravesicular content, and their role in the regulation of tumour progression processes in glioma.

Contribution of Adipose Tissue to Development of Cancer

Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose "organ," and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis. © 2018 American Physiological Society. Compr Physiol 8:237-282, 2018.

Update on the mechanisms of homing of adipose tissue-derived stem cells

Adipose tissue-derived stem cells (ADSCs), which resemble bone marrow mesenchymal stromal cells (BMSCs), have shown great advantages and promise in the field of regenerative medicine. They can be readily harvested in large numbers with low donor-site morbidity. To date, a great number of preclinical and clinical studies have shown ADSCs' safety and efficacy in regenerative medicine. However, a better understanding of the mechanisms of homing of ADSCs is needed to advance the clinical utility of this therapy. In this review, the reports of the homing of ADSCs were searched using Pubmed and Google Scholar to update our knowledge. ADSCs were proved to interact with endothelial cells by expressing the similar integrins with BMSCs. In addition, ADSCs do not possess the dominant ligand for P-selectin, just like BMSCs. Stromal derived factor-1 (SDF-1)/CXCR4 and CXC ligand-5 (CXCL5)/CXCR2 interactions are the two main axes governing ADSCs extravasation from bone marrow vessels. Some more signaling pathways involved in migration of ADSCs have been investigated, including LPA/LPA1 signaling pathway, MAPK/Erk1/2 signaling pathway, RhoA/Rock signaling pathway and PDGF-BB/PDGFR-β signaling pathway. Status quo of a lack of intensive studies on the details of homing of ADSCs should be improved in the near future before clinical application.

Adipose stromal cells mediated switching of the pro-inflammatory profile of M1-like macrophages is facilitated by PGE2: in vitro evaluation

OBJECTIVE

To define if adipose mesenchymal stromal cell (ASC) treatment mediated switching of the pro-inflammatory profile of M1-like macrophages as a means to develop a tailored in vitro efficacy/potency test.

DESIGN

We firstly performed immunohistochemical analysis of CD68, CD80 (M1-like) and CD206 (M2-like) macrophages in osteoarthritic (OA) synovial tissue. ASC were co-cultured in contact and in transwell with activated (GM-CSF + IFNγ)-M1 macrophages. We analyzed IL1β, TNFα, IL6, MIP1α/CCL3, S100A8, S100A9, IL10, CD163 and CD206 by qRT-PCR or immunoassays. Prostaglandin E2 (PGE2) blocking experiments were performed using PGE2 receptor antagonist.

RESULTS

In moderate grade OA synovium we did not always find a higher percentage of CD80 with respect to CD206. M1-like-activated macrophage factors IL1β, TNFα, IL6, MIP1α/CCL3, S100A8 and S100A9 were down-modulated both in contact and in transwell by ASC. However, in both systems ASC induced the typical M2-like macrophage markers IL10, CD163 and CD206. Activated-M1-like macrophages pre-treated with PGE2 receptor antagonist failed to decrease secretion of TNFα, IL6 and to increase that of IL10, CD163 and CD206 when co-cultured with ASC confirming a PGE2 specific role.

CONCLUSIONS

We demonstrated that ASC are responsible for the switching of activated-M1-like inflammatory macrophages to a M2-like phenotype, mainly through PGE2. This evidenced that activated-M1-like macrophages may represent a relevant cell model to test the efficacy/potency of ASC and suggests a specific role of ASC as important determinants in therapeutic dampening of synovial inflammation in OA.

Involvement of PI3K and MMP1 in PDGF-induced Migration of Human Adipose-derived Stem Cells

Human adult stem cells have widely been examined for their clinical application including their wound healing effect in vivo. To function as therapeutic cells, however, cells must represent the ability of directed migration in response to signals. This study aimed to investigate the mechanism of platelet-derived growth factor (PDGF)-induced migration of the human abdominal adipose-derived stem cells (hADSCs) in vitro. A general matrix metalloproteinase (MMP) inhibitor or a MMP2 inhibitor significantly inhibited the PDGF-induced migration. PDGF treatment exhibited greater mRNA level and denser protein level of MMP1. The conditioned medium of PDGF-treated cells showed a caseinolytic activity of MMP1. Transfection of cells with siRNA against MMP1 significantly inhibited MMP1 expression, its caseinolytic activity, and cell migration following PDGF treatment. Phosphatidylinositol 3-kinase (PI3K) inhibitor reduced the migration by about 50% without affecting ERK and MLC proteins. Rho-associated protein kinase inhibitor mostly abolished the migration and MLC proteins. The results suggest that PDGF might signal hADSCs through PI3K, and MMP1 activity could play an important role in this PDGF-induced migration in vitro.

Human Adipose-Derived Stem Cells Labeled with Plasmonic Gold Nanostars for Cellular Tracking and Photothermal Cancer Cell Ablation

BACKGROUND

Gold nanostars are unique nanoplatforms that can be imaged in real time and transform light energy into heat to ablate cells. Adipose-derived stem cells migrate toward tumor niches in response to chemokines. The ability of adipose-derived stem cells to migrate and integrate into tumors makes them ideal vehicles for the targeted delivery of cancer nanotherapeutics.

METHODS

To test the labeling efficiency of gold nanostars, undifferentiated adipose-derived stem cells were incubated with gold nanostars and a commercially available nanoparticle (Qtracker), then imaged using two-photon photoluminescence microscopy. The effects of gold nanostars on cell phenotype, proliferation, and viability were assessed with flow cytometry, 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide metabolic assay, and trypan blue, respectively. Trilineage differentiation of gold nanostar-labeled adipose-derived stem cells was induced with the appropriate media. Photothermolysis was performed on adipose-derived stem cells cultured alone or in co-culture with SKBR3 cancer cells.

RESULTS

Efficient uptake of gold nanostars occurred in adipose-derived stem cells, with persistence of the luminescent signal over 4 days. Labeling efficiency and signal quality were greater than with Qtracker. Gold nanostars did not affect cell phenotype, viability, or proliferation, and exhibited stronger luminescence than Qtracker throughout differentiation. Zones of complete ablation surrounding the gold nanostar-labeled adipose-derived stem cells were observed following photothermolysis in both monoculture and co-culture models.

CONCLUSIONS

Gold nanostars effectively label adipose-derived stem cells without altering cell phenotype. Once labeled, photoactivation of gold nanostar-labeled adipose-derived stem cells ablates neighboring cancer cells, demonstrating the potential of adipose-derived stem cells as a vehicle for the delivery of site-specific cancer therapy.

Role of tumor microenvironment in tumorigenesis

Tumorigenesis is a complex and dynamic process, consisting of three stages: initiation, progression, and metastasis. Tumors are encircled by extracellular matrix (ECM) and stromal cells, and the physiological state of the tumor microenvironment (TME) is closely connected to every step of tumorigenesis. Evidence suggests that the vital components of the TME are fibroblasts and myofibroblasts, neuroendocrine cells, adipose cells, immune and inflammatory cells, the blood and lymphatic vascular networks, and ECM. This manuscript, based on the current studies of the TME, offers a more comprehensive overview of the primary functions of each component of the TME in cancer initiation, progression, and invasion. The manuscript also includes primary therapeutic targeting markers for each player, which may be helpful in treating tumors.

In Vitro Effects of Adipose-Derived Stem Cells on Breast Cancer Cells Harvested From the Same Patient

INTRODUCTION

Fat grafting for breast cancer (BrCa) reconstruction and breast augmentation has become increasingly more popular. A major area of debate and controversy is the effect of adipose-derived stem cells (ASCs) on remnant or undetected BrCa cells. We investigate the in vitro response of BrCa to ASCs in a coculture model with regards to cell migration.

METHODS

The study was approved by the institutional review board. BrCa and adipose tissue specimens either from subcutaneous breast tissue or abdominal lipoaspirate were obtained from the same patient. BrCa cells and ASCs were harvested with either explant culture and/or enzymatic digestion. Tissues were grown in cell culture flasks until adequate cell libraries were established. Adipose-derived stem cells from adipose specimens were characterized with flow cytometry. Immunofluorescence (IF) staining of the initial cell population harvested from the BrCa specimens confirmed the presence of CD24, an epithelial marker of BrCa. A homogenous CD 24+/CD 90- BrCa cell population was obtained with flowcytometric cell sorting. The in vitro migration of BrCa cells was examined in coculture with and without ASCs.

RESULTS

Adipose-derived stem cells harvested from the adipose specimens were positive for mesenchymal stem cell markers CD 105, CD 90, CD 73, and CD 44 and negative for lymphocyte cell marker CD 34 and leukocyte marker CD 45. The percentage of the CD 24+/CD 90- BrCa cells in the initial cell population harvested from BrCa specimens was 0.61%. The BrCa cells morphologically had large nuclei and small cytoplasm in clusters under the light microscope, suggesting a cancer cell phenotype. CD 24 expression on the surface of BrCa cells was confirmed with IF staining. The number of BrCa cells migrated in ASCs coculture was approximately 10 times higher than the number of BrCa cells migrated in BrCa cell only cultures.

CONCLUSIONS

Adipose-derived stem cells significantly increase the migration capacity of BrCa cells in vitro in cocultures. This should be taken into consideration when performing fat grafting to the breast especially in patients with a history of BrCa or strong family history of BrCa.

The Oncologic Safety of Breast Fat Grafting and Contradictions Between Basic Science and Clinical Studies: A Systematic Review of the Recent Literature

Fat grafting is increasingly popular and is becoming a common practice in plastic surgery for postmastectomy breast reconstruction and aesthetic breast augmentation; however, concerns over the oncologic safety remains a controversial and hot topic among scientists and surgeons. Basic science and laboratory research repeatedly show a potentially dangerous effect of adipose-derived stem cells on breast cancer cells; however, clinical research, although limited, continually fails to show an increase in breast cancer recurrence after breast fat grafting, with the exception of 1 small study on a subset patient population with intraepithelial neoplasm of the breast. The aim of this review is to summarize the recent conflicting basic science and clinical data to better understand the safety of breast fat grafting from an oncological perspective.

Fat grafting for breast cancer patients: From basic science to clinical studies

Fat grafting in the surgical treatment of breast cancer has become popular in a short period of time because of the rising expectations of good esthetic results by the patients as well as the simplicity of the technique; however, the oncological safety for breast cancer patients remains a matter of debate. The procedure raises many questions considering that recent in-vitro studies have shown that fat grafting could promote tumor recurrence through diverse mechanisms, or even facilitate distant metastasis. We present a review of the currently available experimental and clinical data in order to describe and discuss patient selection criteria following breast cancer surgery.

Adipose-Derived Stem Cells for Tissue Engineering and Regenerative Medicine Applications

Adipose-derived stem cells (ASCs) are a mesenchymal stem cell source with properties of self-renewal and multipotential differentiation. Compared to bone marrow-derived stem cells (BMSCs), ASCs can be derived from more sources and are harvested more easily. Three-dimensional (3D) tissue engineering scaffolds are better able to mimic the in vivo cellular microenvironment, which benefits the localization, attachment, proliferation, and differentiation of ASCs. Therefore, tissue-engineered ASCs are recognized as an attractive substitute for tissue and organ transplantation. In this paper, we review the characteristics of ASCs, as well as the biomaterials and tissue engineering methods used to proliferate and differentiate ASCs in a 3D environment. Clinical applications of tissue-engineered ASCs are also discussed to reveal the potential and feasibility of using tissue-engineered ASCs in regenerative medicine.

The role of adipose-derived stem cells in breast cancer progression and metastasis

Conventional breast cancer extirpation involves resection of parts of or the whole gland, resulting in asymmetry and disfiguration. Given the unsatisfactory aesthetic outcomes, patients often desire postmastectomy reconstructive procedures. Autologous fat grafting has been proposed for reconstructive purposes for decades to restore form and anatomy after mastectomy. Fat has the inherent advantage of being autologous tissue and the most natural-appearing filler, but given its inconsistent engraftment and retention rates, it lacks reliability. Implementation of autologous fat grafts with cellular adjuncts, such as multipotent adipose-derived stem cells (ADSCs), has shown promising results. However, it is pertinent and critical to question whether these cells could promote any residual tumor cells to proliferate, differentiate, or metastasize or even induce de novo carcinogenesis. Thus far, preclinical and clinical study findings are discordant. A trend towards potential promotion of both breast cancer growth and invasion by ADSCs found in basic science studies was indeed not confirmed in clinical trials. Whether experimental findings eventually correlate with or will be predictive of clinical outcomes remains unclear. Herein, we aimed to concisely review current experimental findings on the interaction of mesenchymal stem cells and breast cancer, mainly focusing on ADSCs as a promising tool for regenerative medicine, and discuss the implications in clinical translation.

Adipose-derived stems cells and their role in human cancer development, growth, progression, and metastasis: a systematic review

Obesity is a well recognized risk factor for several types of cancers, many of which occur solely or disproportionately in women. Adipose tissue is a rich source of adipose-derived stem cells (ASC), which have received attention for their role in cancer behavior. The purpose of this systematic review is to present the existing literature on the role of ASCs in the growth, development, progression, and metastasis of cancer, with an emphasis on malignancies that primarily affect women. To accomplish this goal, the bibliographic database PubMed was systematically searched for articles published between 2001 and 2014 that address ASCs' relationship to human cancer. Thirty-seven articles on ASCs' role in human cancer were reviewed. Literature suggests that ASCs exhibit cancer-promoting properties, influence/are influenced by the tumor microenvironment, promote angiogenesis, and may be associated with pathogenic processes through a variety of mechanisms, such as playing a role in hypoxic tumor microenvironment. ASCs appear to be important contributors to tumor behavior, but research in areas specific to women's cancers, specifically endometrial cancer, is scarce. Also, because obesity continues to be a major health concern, it is important to continue research in this area to improve understanding of the impact adiposity has on cancer incidence.

Recruitment of circulating breast cancer cells is stimulated by radiotherapy

Radiotherapy (RT) is a localized therapy that is highly effective in killing primary tumor cells located within the field of the radiation beam. We present evidence that irradiation of breast tumors can attract migrating breast cancer cells. Granulocyte-macrophage colony stimulating factor (GM-CSF) produced by tumor cells in response to radiation stimulates the recruitment of migrating tumor cells to irradiated tumors, suggesting a mechanism of tumor recurrence after radiation facilitated by transit of unirradiated, viable circulating tumor cells to irradiated tumors. Data supporting this hypothesis are presented through in vitro invasion assays and in vivo orthotopic models of breast cancer. Our work provides a mechanism for tumor recurrence in which RT attracts cells outside the radiation field to migrate to the site of treatment.

Adult adipose-derived stem cells and breast cancer: a controversial relationship

Breast cancer is the most common cancer in women and autologous fat grafting is an important clinical application in treatment of post-surgical deformities. The simplicity of fat grafting procedures and the absence of subsequent visible scar prompted an increasing interest for this technique. The plasticity of adipose-derived stem cells (ASCs) obtained from stromal vascular fraction (SVF) of adult adipose tissue provided exciting perspectives for regenerative medicine and surgery. The recent discovery that SVF/ASC enrichment further ameliorates clinical efficacy of grafting ASCs suggest as ASC-mediated new adipogenesis and vasculogenesis. ASC adipogenic differentiation involves Akt activity and EGFRs, FGFRs, ERbB2 receptor-mediated pathways that also play a pivotal role in the regulation of breast cancer growth. Moreover, the finding that platelet-derived growth factors and hormones improved long-term maintenance of fat grafting raises new concerns for their use during breast reconstruction after cancer surgery. However, it remains unclear whether grafted or resident ASCs may increase the risk of de novo cancer development or recurrence. Preliminary follow-up studies seem to support the efficacy and safety of SVF/ASCs enrichment and the additional benefit from the combined use of autologous platelet-derived growth factors and hormones during breast reconstruction procedures. In the present review we highlighted the complex interplay between resident or grafted ASCs, mature adipocytes, dormant or active breast cancer cells and tumor microenvironment. Actually, data concerning the permissive role of ASCs on breast cancer progression are contrasting, although no clear evidence speaking against their use exists.

Platelet-derived growth factor-C (PDGF-C) induces anti-apoptotic effects on macrophages through Akt and Bad phosphorylation

PDGF-C, which is abundant in the malignant breast tumor microenvironment, plays an important role in cell growth and survival. Because tumor-associated macrophages (TAMs) contribute to cancer malignancy, macrophage survival mechanisms are an attractive area of research into controlling tumor progression. In this study, we investigated PDGF-C-mediated signaling pathways involved in anti-apoptotic effects in macrophages. We found that the human malignant breast cancer cell line MDA-MB-231 produced high quantities of PDGF-C, whereas benign MCF-7 cells did not. Recombinant PDGF-C induced PDGF receptor α chain phosphorylation, followed by Akt and Bad phosphorylation in THP-1-derived macrophages. MDA-MB-231 culture supernatants also activated macrophage PDGF-Rα. PDGF-C prevented staurosporine-induced macrophage apoptosis by inhibiting the activation of caspase-3, -7, -8, and -9 and cleavage of poly(ADP-ribose) polymerase. Finally, TAMs isolated from the PDGF-C knockdown murine breast cancer cell line 4T1 and PDGF-C knockdown MDA-MB-231-derived tumor mass showed higher rates of apoptosis than the respective WT controls. Collectively, our results suggest that tumor cell-derived PDGF-C enhances TAM survival, promoting tumor malignancy.

The co-expression of telomerase and ALT pathway in human breast cancer tissues

Recently, telomerase-targeted therapy was studied intensively; however, many studies have verified the existence of alternative lengthening mechanisms of telomeres in vitro. In the present work, we explored the expression characteristic of the two kinds of telomere-prolonging mechanisms in the breast cancer tissues per se. Furthermore, we studied the relationship between Her-2 expression and ALT pathway. Ninety samples of breast cancer tissues were examined in this research. RT-PCR was used for the detection of the expression of human telomerase reverse transcriptase (hTERT); IHC was used for the detection of the expression of promyelocytic leukemia body (PML) bodies; the co-expression of PML bodies and hTERT was detected using the QDs-based immunofluorescence. The co-expression of PML body and hTERT was found in the same cell in breast cancer tissues, and ten samples expressed neither PML bodies nor hTERT. Additionally, the expression of PML bodies and Her-2 was statistically co-related (P = 0.047). The two kinds of mechanisms of telomere extension can co-exist in the same cell in beast cancer tissues, and there may be other mechanisms of telomere extension functioning in human breast carcinoma.

Ionizing radiation and glioblastoma exosomes: implications in tumor biology and cell migration

Exosomes are nanometer-sized lipid vesicles released ubiquitously by cells, which have been shown to have a normal physiological role, as well as influence the tumor microenvironment and aid metastasis. Recent studies highlight the ability of exosomes to convey tumor-suppressive and oncogenic mRNAs, microRNAs, and proteins to a receiving cell, subsequently activating downstream signaling pathways and influencing cellular phenotype. Here, we show that radiation increases the abundance of exosomes released by glioblastoma cells and normal astrocytes. Exosomes derived from irradiated cells enhanced the migration of recipient cells, and their molecular profiling revealed an abundance of molecules related to signaling pathways important for cell migration. In particular, connective tissue growth factor (CTGF) mRNA and insulin-like growth factor binding protein 2 (IGFBP2) protein levels were elevated, and coculture of nonirradiated cells with exosomes isolated from irradiated cells increased CTGF protein expression in the recipient cells. Additionally, these exosomes enhanced the activation of neurotrophic tyrosine kinase receptor type 1 (TrkA), focal adhesion kinase, Paxillin, and proto-oncogene tyrosine-protein kinase Src (Src) in recipient cells, molecules involved in cell migration. Collectively, our data suggest that radiation influences exosome abundance, specifically alters their molecular composition, and on uptake, promotes a migratory phenotype.

Risk of subsequent primary malignancies after dermatofibrosarcoma protuberans diagnosis: a national study

BACKGROUND

Patients frequently live many years after diagnosis of dermatofibrosarcoma protuberans (DFSP).

OBJECTIVE

We sought to determine the risk of subsequent primary malignancy (SPM) after DFSP diagnosis.

METHODS

Using the Surveillance, Epidemiology, and End Results database (1973-2008) for 3734 patients with DFSP, we compared the risk of developing 14 SPMs (12 most prevalent cancers in the United States plus other nonepithelial and soft tissue) relative to risk in the general population of same sex, race, and age and year of diagnosis.

RESULTS

Patients given the diagnosis of DFSP had an overall increased risk of SPM (observed:expected [O:E], 1.20; 95% confidence intervals [CI], 1.04-1.39), with much of the overall increased risk attributable to increased risk of nonepithelial skin cancer (O:E, 9.94; 95% CI, 3.38-22.30). Specifically, female patients with DFSP were at increased risk of other nonepithelial skin cancer (O:E, 14.50; 95% CI, 3.46-38.98), melanoma (O:E, 2.59; 95% CI, 1.02-5.35), and breast cancer (O:E, 1.44; 95% CI, 1.00-2.00). Male patients were not at increased overall risk (O:E, 1.18; 95% CI, 0.96-1.44) of SPM or at increased risk of any specific malignancy (P > .05) adjusted for multiplicity of t tests.

LIMITATIONS

Surveillance bias may have led to increased rates and earlier detection of primary malignances in patients with DFSP compared with the general population. Individual data that may reveal shared environmental causes of DFSP and SPM were unavailable.

CONCLUSIONS

Patients with DFSP are at increased risk of a number of SPMs.

Adipose tissue and breast epithelial cells: a dangerous dynamic duo in breast cancer

Among the many different cell types surrounding breast cancer cells, the most abundant are those that compose mammary adipose tissue, mainly mature adipocytes and progenitors. New accumulating recent evidences bring the tumor-surrounding adipose tissue into the light as a key component of breast cancer progression. The purpose of this review is to emphasize the role that adipose tissue might play by locally affecting breast cancer cell behavior and subsequent clinical consequences arising from this dialog. Two particular clinical aspects are addressed: obesity that was identified as an independent negative prognostic factor in breast cancer and the oncological safety of autologous fat transfer used in reconstructive surgery for breast cancer patients. This is preceded by the overall description of adipose tissue composition and function with special emphasis on the specificity of adipose depots and the species differences, key experimental aspects that need to be taken in account when cancer is considered.

Epithelial-mesenchymal transition in breast cancer lines is mediated through PDGF-D released by tissue-resident stem cells

Epithelial-mesenchymal transition (EMT) generates tumor cells with stem cell properties. The aim of our study was to investigate the effects of adipose tissue-derived stem cells (ASCs) on EMT of cancer cells and to further investigate the mechanisms involved. We demonstrate that conditioned medium from ASCs induces breast cancer cells (4T1) to express mesenchymal markers such as fibronectin, alpha smooth muscle actin and vimentin. Flow cytometry analyses show that ASC-conditioned medium promotes the expansion of CD44high/CD24low cancer stem cells. Soft agar assays using T47D, BT474 and MCF-7 breast cancer cells reveals that ASC conditioned medium promotes the anchorage-independent growth of cancer cells. These effects were inhibited by a neutralizing antibody against platelet-derived growth factor-D (PDGF-D). Furthermore, PDGF-D treated breast cancer cells grow faster in a mouse model, and this effect could be neutralized by a PDGF antibody. In conclusion, our data show that tissue-resident stem cells interact with the cancer microenvironment via PDGF-D, induce EMT in the cancer cells in a paracrine fashion, thereby increasing the number of cancer stem cells and increase tumor growth in a PDGF dependent manner. Our findings shed new light on mechanisms where local tissue-resident stem cells are able to promote the growth of breast cancer cells. Possibly this could open up a novel selective therapeutic strategy targeting EMT pathways and the specific communication between tissue-resident normal stem cell and cancer stem cells, assuming that the blockage of PDGF-D pathways is critical for tumor growth but would not affect normal tissue homeostasis.

Inhibitory effect of soluble platelet-derived growth factor receptor β on intraosseous growth of breast cancer cells in nude mice

Bone metastasis is a frequent complication of advanced breast cancer. On the basis of functional and molecular evidence, signaling mediated by the binding of platelet-derived growth factor (PDGF)-BB and -DD to PDGF receptor β (PDGFRβ) is critical for the survival and growth of metastatic breast cancer cells within the bone microenvironment. In this study, we propose a new approach to blocking PDGFRβ signaling using soluble PDGFRβ (sPDGFRβ) as a decoy receptor for PDGF-BB and -DD secreted from tumor cells and bone marrow stromal cells. A bone-seeking TNBCT/Bo cell line was established by in vivo selection from TNBCT human breast cancer cells, which are negative for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 protein expression. The TNBCT/Bo cells were transfected with a mammalian expression vector encoding the extracellular domain of PDGFRβ. A stable transfectant (TNBCT/Bo-sPDGFRβ) grew at a similar rate to that of control cells under normal culture conditions, although growth stimulation of human fibroblasts with PDGF-BB was neutralized by the culture medium from TNBCT/Bo-sPDGFRβ cells. Intratibial injection of TNBCT/Bo-sPDGFRβ cells into athymic nude mice resulted in a significant decrease in tumor incidence compared with control mice (P < 0.01). This attenuated growth correlated with decreased cancer cell proliferation, angiogenesis, and recruitment of stromal cells, and with an increase in the number of apoptotic cells. These findings suggest that sPDGFRβ is useful for the treatment of breast cancer bone metastasis.

PDGF: the nuts and bolts of signalling toolbox

PDGF is a growth factor and is extensively involved in multi-dimensional cellular dynamics. It switches on a plethora of molecules other than its classical pathway. It is engaged in various transitions of development; however, if the unleashed potentials lead astray, it brings forth tumourigenesis. Conventionally, it has been assumed that the components of this signalling pathway show fidelity and act with a high degree of autonomy. However, as illustrated by the PDGF signal transduction, reinterpretation of recent data suggests that machinery is often shared between multiple pathways, and other components crosstalk to each other through multiple mechanisms. It is important to note that metastatic cascade is an intricate process that we have only begun to understand in recent years. Many of the early steps of this PDGF cascade are not readily targetable in the clinic. In this review, we will unravel the paradoxes with reference to mitrons and cellular plasticity and discuss how disruption of signalling cascade triggers cellular proliferation phase transition and metastasis. We will also focus on the therapeutic interventions to counteract resultant molecular disorders.