Adult Stem Cell Functioning in the Tumor Micro-Environment

The Multifunction Role of Tumor-Associated Mesenchymal Stem Cells and Their Interaction with Immune Cells in Breast Cancer

Mesenchymal stem cells (MSCs) are a heterogeneous group of progenitor cells that play a multifunctional role including tissue regeneration, self-renewal properties, and differentiate into cells of mesodermal lineage such as adipocytes, osteoblasts, and chondrocytes. MSCs come into contact with tumor microenvironment (TME) and differentiate into tumor-associated MSCs (TA-MSCs). Various substances such as chemokines, cytokines, growth factors, and others are released by tumor cells to recruit MSCs. TA-MSCs induced epithelial-mesenchymal transition (EMT) program which mediates tumor growth progression, migration, and invasion. Role of MSCs in the tumor progression, stemness, malignancy, and treatment resistance in the breast cancer TME. Immunomodulation by MSCs is mediated by a combination of cell contact-dependent mechanisms and soluble substances. Monocytes/macrophages, dendritic cells, T cells, B cells, and NK cells all show signs of MSCs' immunomodulatory capability. In a complicated interplay initiated by MSCs, anti-inflammatory monocytes/macrophages and regulatory T cells (Tregs) play a key role, as they unveil their full immunomodulatory potential. MSC- secreted cytokines are commonly blamed for the interaction between MSCs, monocytes, and Tregs. Here, we review the current knowledge of cellular and molecular mechanisms involved in MSC-mediated immunomodulation and focus on the role MSCs play in breast cancer progression and its TME.Abbreviation MSC: Mesenchymal Stem Cells; TME: Tumor Microenvironment; TAMS; Tumour-associated Macrophages; ECM: Extracellular matrix; CAFs: Cancer-associated Fibroblasts; CFUs: Colony-forming unit Fibroblasts; Tregs: T regulatory cells; Bregs; Regulatory B cells; IFN-γ: Interferon-gamma; TNF-α: Tumour Necrosis Factor-alpha; IL: Interleukin; TGF-β: transforming growth factorβ; PGE2: Prostaglandin E2; CXCR: Chemokine Receptor; Blimp-1; B lymphocyte-induced maturation protein-1; CCL: Chemokine motif ligand; EMT: Epithelial-mesenchymal transition.

The Effect of Stem Cells and Vascular Endothelial Growth Factor on Cancer Angiogenesis

The formation of new vessels from pre-existing vessels is known as angiogenesis. The process is controlled by stimuli and inhibitors. Angiogenesis starts as a result of the unbalance of these factors, where balance has a tendency toward the stimulus. One of the most important factors promoting angiogenesis is the vascular endothelial growth factor (VEGF). In addition to being involved in vascular regeneration in normal tissues, VEGF also takes part in tumor tissue angiogenesis. These factors affect endothelial cells (ECs) directly as well as differentiate tumor cells from endothelial cells and play an active role in tumor tissue angiogenesis. Angiogenesis partakes in the growth and proliferation of tumor tissue. Because anti-angiogenic treatment is favorable in existing cancer therapies, the potential benefits should be considered. One of these new therapies is cell therapy using mesenchymal stem cells (MSCs). Research on MSCs remains controversial because much of the earlier research on MSCs has shown their effectiveness, but more recent research has identified harmful effects of these cells. This article reviews the role of stem cells and their secretions in the angiogenesis of tumor tissues.

Identification of Surface Antigens That Define Human Pluripotent Stem Cell-Derived PRRX1+Limb-Bud-like Mesenchymal Cells

Stem cell-based therapies and experimental methods rely on efficient induction of human pluripotent stem cells (hPSCs). During limb development, the lateral plate mesoderm (LPM) produces limb-bud mesenchymal (LBM) cells that differentiate into osteochondroprogenitor cells and form cartilage tissues in the appendicular skeleton. Previously, we generated PRRX1-tdTomato reporter hPSCs to establish the protocol for inducing the hPSC-derived PRRX1⁺ LBM-like cells. However, surface antigens that assess the induction efficiency of hPSC-derived PRRX1⁺ LBM-like cells from LPM have not been identified. Here, we used PRRX1-tdTomato reporter hPSCs and found that high pluripotent cell density suppressed the expression of PRRX1 mRNA and tdTomato after LBM-like induction. RNA sequencing and flow cytometry suggested that PRRX1-tdTomato⁺ LBM-like cells are defined as CD44^high CD140B^high CD49f⁻. Importantly, other hPSC lines, including four human induced pluripotent stem cell lines (414C2, 1383D2, HPS1042, HPS1043) and two human embryonic stem cell lines (SEES4, SEES7), showed the same results. Thus, an appropriate cell density of hPSCs before differentiation is a prerequisite for inducing the CD44^high CD140B^high CD49f⁻ PRRX1⁺ LBM-like cells.

Adipose derived mesenchymal stem cell secretome formulation as a biotherapeutic to inhibit growth of drug resistant triple negative breast cancer

In the present study, a protocol was developed for processing of human adipose derived mesenchymal stem cell secretome formulation of varying concentration. Its molecular composition was evaluated, and its effectiveness in vitro using breast cancer cell lines, and in vivo in a nude mice breast cancer model was studied to determine its role in suppressing triple negative breast cancer in a dose dependent manner. Because the secretome could have value as an add-on therapy along with a current drug, the effectiveness of the secretome both in monotherapy and in combination therapy along with paclitaxel was evaluated. The results showed significant cell kill when exposed to the secretome above 20 mg/ml at which concentration there was no toxicity to normal cells. 70 mg/ml of SF showed 90 ± 10% apoptosis and significant decrease in CD44⁺/CD24⁻, MDR1+ and PDL-1+ cancer cells. In vivo, the tumor showed no growth after daily intra tumor injections at 50 mg/ml and 100 mg/ml doses whereas substantial tumor growth occurred after saline intra tumor injection. The study concludes that SF is a potential biotherapeutic for breast cancer and could be used initially as an add-on therapy to other standard of care to provide improved efficacy without other adverse effects.

Allogeneic vs. autologous mesenchymal stem/stromal cells in their medication practice

Mesenchymal stem/stromal cell (MSC)-based therapeutics is already available for treatment of a range of diseases or medical conditions. Autologous or allogeneic MSCs obtained from self or donors have their own advantages and disadvantages in their medical practice. Therapeutic benefits of using autologous vs. allogeneic MSCs are inconclusive. Transplanted MSCs within the body interact with their physical microenvironment or niche, physiologically or pathologically, and such cells in a newly established tissue microenvironment may be impacted by the pathological harmful environmental factors to alter their unique biological behaviors. Meanwhile, a temporary microenvironment/niche may be also altered by the resident or niche-surrounding MSCs. Therefore, the functional plasticity and heterogeneity of MSCs caused by different donors and subpopulations of MSCs may result in potential uncertainty in their safe and efficacious medical practice. Acknowledging a connection between MSCs' biology and their existing microenvironment, donor-controlled clinical practice for the long-term therapeutic benefit is suggested to further consider minimizing MSCs potential harm for MSC-based individual therapies. In this review, we summarize the advantages and disadvantages of autologous vs. allogeneic MSCs in their therapeutic applications. Among other issues, we highlight the importance of better understanding of the various microenvironments that may affect the properties of niche-surrounding MSCs and discuss the clinical applications of MSCs within different contexts for treatment of different diseases including cardiomyopathy, lupus and lupus nephritis, diabetes and diabetic complications, bone and cartilage repair, cancer and tissue fibrosis.

Nanobiotechnology-assisted therapies to manage brain cancer in personalized manner

There are numerous investigated factors that limit brain cancer treatment efficacy such as ability of prescribed therapy to cross the blood-brain barrier (BBB), tumor specific delivery of a therapeutics, transport within brain interstitium, and resistance of tumor cells against therapies. Recent breakthroughs in the field of nano-biotechnology associated with developing multifunctional nano-theranostic emerged as an effective way to manage brain cancer in terms of higher efficacy and least possible adverse effects. Keeping challenges and state-of-art accomplishments into consideration, this review proposes a comprehensive, careful, and critical discussion focused on efficient nano-enabled platforms including nanocarriers for drug delivery across the BBB and nano-assisted therapies (e.g., nano-immunotherapy, nano-stem cell therapy, and nano-gene therapy) investigated for brain cancer treatment. Besides therapeutic efficacy point-of-view, efforts are being made to explore ways projected to tune such developed nano-therapeutic for treating patients in personalized manner via controlling size, drug loading, delivery, and retention. Personalized brain tumor management based on advanced nano-therapies can potentially lead to excellent therapeutic benefits based on unique genetic signatures in patients and their individual disease profile. Moreover, applicability of nano-systems as stimulants to manage the brain cancer growth factors has also been discussed in photodynamic therapy and radiotherapy. Overall, this review offers a comprehensive information on emerging opportunities in nanotechnology for advancing the brain cancer treatment.

How the Pathological Microenvironment Affects the Behavior of Mesenchymal Stem Cells in the Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic disease characterized by fibroblasts activation, ECM accumulation, and diffused alveolar inflammation. The role of inflammation in IPF is still controversial and its involvement may follow nontraditional mechanisms. It is seen that a pathological microenvironment may affect cells, in particular mesenchymal stem cells (MSCs) that may be able to sustain the inflamed microenvironment and influence the surrounding cells. Here MSCs have been isolated from fibrotic (IPF-MSCs) and control (C-MSCs) lung tissue; first cells were characterized and compared by the expression of molecules related to ECM, inflammation, and other interdependent pathways such as hypoxia and oxidative stress. Subsequently, MSCs were co-cultured between them and with NHLF to test the effects of the cellular crosstalk. Results showed that pathological microenvironment modified the features of MSCs: IPF-MSCs, compared to C-MSCs, express higher level of molecules related to ECM, inflammation, oxidative stress, and hypoxia; notably, when co-cultured with C-MSCs and NHLF, IPF-MSCs are able to induce a pathological phenotype on the surrounding cell types. In conclusion, in IPF the pathological microenvironment affects MSCs that in turn can modulate the behavior of other cell types favoring the progression of IPF.

Crosstalk Between Mesenchymal Stromal Cells and Tumor-Associated Macrophages in Gastric Cancer

Tumor microenvironment (TME) consisting of distinct cell types including stromal cells and immune cells has recently emerged as a pivotal player in tumor development and progression. Mesenchymal stromal cells (MSCs) and tumor-associated macrophages (TAMs) are two representative cells in the TME with plastic properties. This review will focus on the evolution of phenotypes and functions of either MSCs or TAMs, which is “educated” by the TME, as well as interactions between MSCs and TAMs contributing to the distinct stages of tumor biology in gastric cancer. MSCs exert immunoregulatory effects on macrophages and polarize them toward M2-like TAMs, via cell–cell contact and paracrine or extracellular vesicle (EV) transfer mechanism. In turn, M2-TAMs modulate the transition of “naive” MSCs into tumor-derived MSCs, which possess a more potent pro-tumor role than the parent. Moreover, the cross talk between MSCs and TAMs could contribute to cancer biology by inducing the EMT process, metastasis, immune invasion, and immunotherapy resistance in cancer cells. However, molecular mechanisms underlying interactions between MSCs and TAMs in gastric cancer progression need to be thoroughly elucidated, which may provide attractive targets for making promising novel strategies for gastric cancer therapy.

Zebrafish xenograft model of human lung cancer for studying the function of LINC00152 in cell proliferation and invasion

Background

Numerous studies have shown that long noncoding RNAs play important roles in human cancer progression. Although zebrafish xenografts have recently become a novel in vivo model for human cancer research, whether such models can be used to study the function of long noncoding RNAs remains unknown.

Methods

In vitro studies validated the roles of LINC00152 in the proliferation and invasion of lung cancer cells. In vivo studies of zebrafish xenografts also confirmed these roles of LINC00152. In vivo confocal imaging was used to more accurately evaluate the function of LINC00152 in cell proliferation and migration. Pharmacological experiments were further performed to study the potential ability of LINC00152 downregulation combined with an EGFR inhibitor to treat tumors in cultured cells and the zebrafish xenograft model.

Results

Silencing of LINC00152 suppressed cell proliferation and invasion in SPCA1 and A549 lung cancer cell lines in vitro. In the zebrafish xenograft model, knockdown of LINC00152 reduced the proliferation and migration of lung cancer cells, as indicated by the two imaging methods at different magnifications. Moreover, the knockdown of LINC00152 enhanced the inhibition effect of afatinib for lung cancer progression in cultured cells and the zebrafish xenograft model.

Conclusion

Our study reveals the oncogenic roles and potential for LINC00152 to be a target for tumor treatment in lung cancer using zebrafish xenograft models, and the findings suggest that this model could be used for functional and application studies of human long noncoding RNAs in tumor biology.

Combined Fascin-1 and MAP17 Expression in Breast Cancer Identifies Patients with High Risk for Disease Recurrence

BACKGROUND AND OBJECTIVE

Breast cancer stem cells are considered to be a major cause of disease recurrence in breast cancer as they appear to be chemoresistant. Fascin-1 and MAP17 are stem cell markers whose excessive expression in tumors is associated with aggressive tumor phenotypes. The aim of the present study was to investigate the expression patterns of fascin-1 and MAP17 in breast cancer and to assess their clinical significance.

METHODS

Expression of fascin-1 and MAP17 was assessed via immunohistochemistry in surgical specimens of a cohort comprised of 127 patients with resectable breast cancer. Results were correlated with clinicopathological characteristics and survival data. Progression-free survival (PFS) was defined as the primary outcome of the present study.

RESULTS

Fascin-1 and MAP17 expression were strongly associated with the presence of triple-negative cancers (p < 0.0001). Tumors displaying high expression of fascin-1 presented correlations with high tumor grade (p = 0.002) and high expression of Ki-67 (p = 0.004). PFS of patients exhibiting high expression of fascin-1 and MAP17 in cancer cells in the first 5 years after surgery was significantly worse than in patients with low expression of the two markers (47.8%, 95% confidence interval [CI] 33-51 vs. 80.5%, 95% CI 47-56; p = 0.012) and independent of other clinicopathological characteristics (hazard ratio 0.171, 95% CI 0.034-0.869; p = 0.033).

CONCLUSION

Combined expression of fascin-1 and MAP17 in breast cancer cells is associated with a significantly worse 5-year PFS, therefore recognizing a group of patients with high risk for early disease recurrence.

Recent Progress of Stem Cell Therapy in Cancer Treatment: Molecular Mechanisms and Potential Applications

The insufficient and unspecific target of traditional therapeutic approaches in cancer treatment often leads to therapy resistance and cancer recurrence. Over the past decades, accumulating discoveries about stem cell biology have provided new potential approaches to cure cancer patients. Stem cells possess unique biological actions, including self-renewal, directional migration, differentiation, and modulatory effects on other cells, which can be utilized as regenerative medicine, therapeutic carriers, drug targeting, and generation of immune cells. In this review, we emphasize the mechanisms underlying the use of various types of stem cells in cancer treatment. In addition, we summarize recent progress in the clinical applications of stem cells, as well as common risks of this therapy. We finally give general directions for future studies, aiming to improve overall outcomes in the fight against cancer.

Bidirectional and Opposite Effects of Naïve Mesenchymal Stem Cells on Tumor Growth and Progression

Cancer has long been considered as a heterogeneous population of uncontrolled proliferation of different transformed cell types. The recent findings concerning tumorigeneses have highlighted the fact that tumors can progress through tight relationships among tumor cells, cellular, and non-cellular components which are present within tumor tissues. In recent years, studies have shown that mesenchymal stem cells (MSCs) are essential components of non-tumor cells within the tumor tissues that can strongly affect tumor development. Several forms of MSCs have been identified within tumor stroma. Naïve (innate) mesenchymal stem cells (N-MSCs) derived from different sources are mostly recruited into the tumor stroma. N-MSCs exert dual and divergent effects on tumor growth through different conditions and factors such as toll-like receptor priming (TLR-priming), which is the primary underlying causes of opposite effects. Moreover, MSCs also have the contrary effects by various molecular mechanisms relying on direct cellto- cell connections and indirect communications through the autocrine, paracrine routes, and tumor microenvironment (TME).

Overall, cell-based therapies will hold great promise to provide novel anticancer treatments. However, the application of intact MSCs in cancer treatment can theoretically cause adverse clinical outcomes. It is essential that to extensively analysis the effective factors and conditions in which underlying mechanisms are adopted by MSCs when encounter with cancer.

The aim is to review the cellular and molecular mechanisms underlying the dual effects of MSCs followed by the importance of polarization of MSCs through priming of TLRs.