Adipose-derived mesenchymal stromal/stem cells (AD-MSC) may offer efficient tools for cell-based gene therapy approaches. In this study, we evaluated whether AD-MSC could deliver proapoptotic molecules for cancer treatment. Human AD-MSCs were isolated and transduced with a retroviral vector encoding full-length human tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a proapoptotic ligand that induces apoptosis in a variety of human cancers but not normal tissues. Although several studies have documented the antitumor activity of recombinant human TRAIL, its use in vivo is limited by a short half-life in plasma due to a rapid clearance by the kidney. We found that these limitations can be overcome using stably transduced AD-MSC, which could serve as a constant source of TRAIL production. AD-MSC armed with TRAIL targeted a variety of tumor cell lines in vitro, including human cervical carcinoma, pancreatic cancer, colon cancer, and, in combination with bortezomib, TRAIL-resistant breast cancer cells. Killing activity was associated with activation of caspase-8 as expected. When injected i.v. or s.c. into mice, AD-MSC armed with TRAIL localized into tumors and mediated apoptosis without significant apparent toxicities to normal tissues. Collectively, our results provide preclinical support for a model of TRAIL-based cancer therapy relying on the use of adiposederived mesenchymal progenitors as cellular vectors. Cancer Res; 70(9); 3718-29. ©2010 AACR.

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The use of fetal bovine serum (FBS) as a cell culture supplement is discouraged by regulatory authorities to limit the risk of zoonoses and xenogeneic immune reactions in the transplanted host. Additionally, FBS production came under scrutiny due to animal welfare concerns. Platelet derivatives have been proposed as FBS substitutes for the ex-vivo expansion of mesenchymal stem/stromal cells (MSCs) since platelet-derived growth factors can promote MSC ex-vivo expansion. Platelet-derived growth factors are present in platelet lysate (PL) obtained after repeated freezing–thawing cycles of the platelet-rich plasma or by applying physiological stimuli such as thrombin or CaCl2.PL-expanded MSCs have been used already in the clinic, taking advantage of their faster proliferation compared with FBS-expanded preparations. Should PL be applied to other biopharmaceutical products, its demand is likely to increase dramatically. The use of fresh platelet units for the production of PL raises concerns due to limited availability of platelet donors. Expired units might represent an alternative, but further data are needed to define safety, including pathogen reduction, and functionality of the obtained PL. In addition, relevant questions concerning the definition of PL release criteria, including concentration ranges of specific growth factors in PL batches for various clinical indications, also need to be addressed. We are still far from a common definition of PL and standardized PL manufacture due to our limited knowledge of the mechanisms that mediate PL-promoting cell growth. Here, we concisely discuss aspects of PL as MSC culture supplement as a preliminary step towards an agreed definition of the required characteristics of PL for the requirements of manufacturers and users.

Tumor stromal cells can supply appropriate signals that may develop aggressive phenotypes of carcinoma cells and establish a complex scenario which culminates in metastasis. Recent works proposed that bone marrow-derived mesenchymal stem cells (MSC) are recruited to primary tumors. However, the exact functions of these cells in the tumor microenvironment are not well characterized, as it is reported that MSC can either promote or inhibit tumor progression. In the present study, we aim at investigating the signaling molecules which regulate the interplay between MSC, prostate carcinoma (PCa) cells and two important cellular types constituting the tumor-associated stroma, macrophages and fibroblasts, during their progression toward malignancy. We identified TGF-β1 as a crucial molecule able to attract MSC recruitment both to PCa cells as well as to tumor stroma components. Moreover, PCa- and tumor stroma-secreted TGF-β1 is important to induce MSC transdifferentiation into carcinoma-associated fibroblast (CAF)-like cells. Consequently, the CAF-like phenotype acquired by MSC is central to promote tumor progression related effects. Thus, tumor-educated MSC enhance PCa invasiveness compared to nonactivated MSC. Additionally, differing from normal MSC, CAF-like MSC perform vascular mimicry and recruit monocytes, which can be further polarized to M2 macrophages within the PCa environment. Our findings indicate a prominent role for TGF-β1 in MSC mobilization and activation strengthened by the fact that the blockade of TGF-β1 signaling impairs MSC promotion of PCa progression. Stem Cells 2016;34:2536-2547.

Background: The stromal vascular fraction (SVF) is a heterogeneous cell population derived from the adipose tissue. There is still a lack of information concerning the characterization of the cell subpopulations constituting the SVF as well as its mesenchymal and haematopoietic potential. Furthermore there are great variations in its phenotypical characterization.

Stress has an emerging role in cancer and targeting stress-related β-adrenergic receptors (AR) has been proposed as a potential therapeutic approach in melanoma. Here we report that β3-AR expression correlates with melanoma aggressiveness. In addition, we highlight that β3-AR expression is not only restricted to cancer cells, but it is also expressed in vivo in stromal, inflammatory and vascular cells of the melanoma microenvironment. Particularly, we demonstrated that β3-AR can (i) instruct melanoma cells to respond to environmental stimuli, (ii) enhance melanoma cells response to stromal fibroblasts and macrophages, (iii) increase melanoma cell motility and (iv) induce stem-like traits. Noteworthy, β3-AR activation in melanoma accessory cells drives stromal reactivity by inducing pro-inflammatory cytokines secretion and de novo angiogenesis, sustaining tumor growth and melanoma aggressiveness. β3-ARs also play a mandatory role in the recruitment to tumor sites of circulating stromal cells precursors, in the differentiation of these cells towards different lineages, further favoring tumor inflammation, angiogenesis and ultimately melanoma malignancy. Our findings validate selective β3-AR antagonists as potential promising anti-metastatic agents. These could be used to complement current therapeutic approaches for melanoma patients (e.g. propranolol) by targeting non-neoplastic stromal cells, hence reducing therapy resistance of melanoma.

Our findings provide additional insights into the genetic and biological basis of inherited genetic susceptibility to DTC. Additional studies are needed to determine the role of the identified polymorphisms in the development of DTC and their possible use in the clinical practice.

Tumor targeting by genetically modified mesenchymal stromal/stem cells (MSCs) carrying anti-cancer molecules represents a promising cell-based strategy. We previously showed that the pro-apoptotic agent tumor necrosis factor-related apoptosisinducing ligand (TRAIL) can be successfully delivered by MSCs to cancer sites. While the interaction between TRAIL and its receptors is clear, more obscure is the way in which MSCs can selectively target tumors and their antigens. Several neuroectoderm-derived neoplasms, including glioblastoma (GBM), sarcomas, and neuroblastoma, express high levels of the tumor-associated antigen GD2. We have already challenged this cell surface disialoganglioside by a chimeric antigen receptor (CAR)-T cell approach against neuroblastoma. With the intent to maximize the therapeutic profile of MSCs delivering TRAIL, we here originally developed a bi-functional strategy where TRAIL is delivered by MSCs that are also gene modified with the truncated form of the anti-GD2 CAR (GD2 tCAR) to mediate an immunoselective recognition of GD2-positive tumors. These bi-functional MSCs expressed high levels of TRAIL and GD2 tCAR associated with a robust anti-tumor activity against GD2-positive GBM cells. Most importantly, the anti-cancer action was reinforced by the enhanced targeting potential of such bi-functional cells. Collectively, our results suggest that a truncated anti-GD2 CAR might be a powerful new tool to redirect MSCs carrying TRAIL against GD2-expressing tumors. This affinity-based dual targeting holds the promise to combine site-specific and prolonged retention of MSCs in GD2-expressing tumors, thereby providing a more effective delivery of TRAIL for still incurable cancers.