Mesenchymal stem cells maintain the stemness of colon cancer stem cells via interleukin-8/mitogen-activated protein kinase signaling pathway

CXCL3/TGF-β-mediated crosstalk between CAFs and tumor cells augments RCC progression and sunitinib resistance

Cancer-associated fibroblasts (CAFs) play a significant role in tumor development and treatment failure, yet the precise mechanisms underlying their contribution to renal cell carcinoma (RCC) remains underexplored. This study explored the interaction between CAFs and tumor cells, and related mechanisms. CAFs isolated from tumor tissues promoted the tumor progression and drugs resistance both in vivo and in vitro. Mechanistically, chemokine (C-X-C motif) ligand (CXCL) 3 secreted from CAFs mediated its effects. CXCL3 activated its receptor CXCR2 to active the downstream ERK1/2 signaling pathway, subsequently promoting epithelial-mesenchymal transition and cell stemness. Blocking the crosstalk between CAFs and tumor cells by CXCR2 inhibitor SB225002 attenuated the functions of CAFs. Furthermore, Renca cells facilitated the transformation of normal interstitial fibroblasts (NFs) into CAFs and the expression of CXCL3 through TGF-β-Smad2/3 signaling pathway. In turn, transformed NFs promoted the tumor progression and drug resistance of RCC. These findings may constitute potential therapeutic strategies for RCC treatment.

Single Mesenchymal Stromal Cell Migration Tracking into Glioblastoma Using Photoconvertible Vesicles

Reliable cell labeling and tracking techniques are imperative for elucidating the intricate and ambiguous interactions between mesenchymal stromal cells (MSCs) and tumors. Here, we explore fluorescent photoconvertible nanoengineered vesicles to study mMSC migration in brain tumors. These 3 μm sized vesicles made of carbon nanoparticles, Rhodamine B (RhB), and polyelectrolytes are readily internalized by cells. The dye undergoes photoconversion under 561 nm laser exposure with a fluorescence blue shift upon demand. The optimal laser irradiation duration for photoconversion was 0.4 ms, which provided a maximal blue shift of the fluorescent signal label without excessive laser exposure on cells. Vesicles modified with an extra polymer layer demonstrated enhanced intracellular uptake without remarkable effects on cell viability, motility, or proliferation. The optimal ratio of 20 vesicles per mMSC was determined. Moreover, the migration of individual mMSCs within 2D and 3D glioblastoma cell (EPNT-5) colonies over 2 days and in vivo tumor settings over 7 days were traced. Our study provides a robust nanocomposite platform for investigating MSC-tumor dynamics and offers insights into envisaged therapeutic strategies. Photoconvertible vesicles also present an indispensable tool for studying complex fundamental processes of cell-cell interactions for a wide range of problems in biomedicine.

Integrated transcriptomics of human blood vessels defines a spatially controlled niche for early mesenchymal progenitor cells

Human blood vessel walls show concentric layers, with the outermost tunica adventitia harboring mesenchymal progenitor cells. These progenitor cells maintain vessel homeostasis and provide a robust cell source for cell-based therapies. However, human adventitial stem cell niche has not been studied in detail. Here, using spatial and single-cell transcriptomics, we characterized the phenotype, potential, and microanatomic distribution of human perivascular progenitors. Initially, spatial transcriptomics identified heterogeneity between perivascular layers of arteries and veins and delineated the tunica adventitia into inner and outer layers. From this spatial atlas, we inferred a hierarchy of mesenchymal progenitors dictated by a more primitive cell with a high surface expression of CD201 (PROCR). When isolated from humans and mice, CD201Low expression typified a mesodermal committed subset with higher osteogenesis and less proliferation than CD201High cells, with a downstream effect on canonical Wnt signaling through DACT2. CD201Low cells also displayed high translational potential for bone tissue generation.

Cancer stem cells: advances in knowledge and implications for cancer therapy

Cancer stem cells (CSCs), a small subset of cells in tumors that are characterized by self-renewal and continuous proliferation, lead to tumorigenesis, metastasis, and maintain tumor heterogeneity. Cancer continues to be a significant global disease burden. In the past, surgery, radiotherapy, and chemotherapy were the main cancer treatments. The technology of cancer treatments continues to develop and advance, and the emergence of targeted therapy, and immunotherapy provides more options for patients to a certain extent. However, the limitations of efficacy and treatment resistance are still inevitable. Our review begins with a brief introduction of the historical discoveries, original hypotheses, and pathways that regulate CSCs, such as WNT/β-Catenin, hedgehog, Notch, NF-κB, JAK/STAT, TGF-β, PI3K/AKT, PPAR pathway, and their crosstalk. We focus on the role of CSCs in various therapeutic outcomes and resistance, including how the treatments affect the content of CSCs and the alteration of related molecules, CSCs-mediated therapeutic resistance, and the clinical value of targeting CSCs in patients with refractory, progressed or advanced tumors. In summary, CSCs affect therapeutic efficacy, and the treatment method of targeting CSCs is still difficult to determine. Clarifying regulatory mechanisms and targeting biomarkers of CSCs is currently the mainstream idea.

Functional Roles of CD133: More than Stemness Associated Factor Regulated by the Microenvironment

CD133 protein has been one of the most used surface markers to select and identify cancer cells with stem-like features. However, its expression is not restricted to tumoral cells; it is also expressed in differentiated cells and stem/progenitor cells in various normal tissues. CD133 participates in several cellular processes, in part orchestrating signal transduction of essential pathways that frequently are dysregulated in cancer, such as PI3K/Akt signaling and the Wnt/β-catenin pathway. CD133 expression correlates with enhanced cell self-renewal, migration, invasion, and survival under stress conditions in cancer. Aside from the intrinsic cell mechanisms that regulate CD133 expression in each cellular type, extrinsic factors from the surrounding niche can also impact CD33 levels. The enhanced CD133 expression in cells can confer adaptive advantages by amplifying the activation of a specific signaling pathway in a context-dependent manner. In this review, we do not only describe the CD133 physiological functions known so far, but importantly, we analyze how the microenvironment changes impact the regulation of CD133 functions emphasizing its value as a marker of cell adaptability beyond a cancer-stem cell marker.

Role of cancer-educated mesenchymal stromal cells on tumor progression

The malignant tumor is the main cause of human deaths worldwide. Current therapies focusing on the tumor itself have achieved unprecedented benefits. Various pro-tumorigenic factors in the tumor microenvironment (TME) could abolish the effect of cancer therapy. Mesenchymal stromal cells (MSCs) are one of the substantial components in the tumor microenvironment, contributing to tumor progression. However, MSCs are not inherently tumor-promoting. Indeed, they acquire pro-tumorigenic properties under the education of the TME. We herein review how various elements in the TME including tumor cells, immune cells, pro-inflammatory factors, hypoxia, and extracellular matrix influence the biological characteristics of MSCs through complex interactions and demonstrate the underlying mechanisms. We also highlight the importance of tumor-associated mesenchymal stromal cells (TA-MSCs) in promoting tumor progression. Our review gives a new insight into the TA-MSCs as a potential tumor therapeutic target. It is anticipated that subverting MSCs education will facilitate the outbreak of therapeutic strategies against tumors.

How the interplay among the tumor microenvironment and the gut microbiota influences the stemness of colorectal cancer cells

Colorectal cancer (CRC) remains the third most prevalent cancer disease and involves a multi-step process in which intestinal cells acquire malignant characteristics. It is well established that the appearance of distal metastasis in CRC patients is the cause of a poor prognosis and treatment failure. Nevertheless, in the last decades, CRC aggressiveness and progression have been attributed to a specific cell population called CRC stem cells (CCSC) with features like tumor initiation capacity, self-renewal capacity, and acquired multidrug resistance. Emerging data highlight the concept of this cell subtype as a plastic entity that has a dynamic status and can be originated from different types of cells through genetic and epigenetic changes. These alterations are modulated by complex and dynamic crosstalk with environmental factors by paracrine signaling. It is known that in the tumor niche, different cell types, structures, and biomolecules coexist and interact with cancer cells favoring cancer growth and development. Together, these components constitute the tumor microenvironment (TME). Most recently, researchers have also deepened the influence of the complex variety of microorganisms that inhabit the intestinal mucosa, collectively known as gut microbiota, on CRC. Both TME and microorganisms participate in inflammatory processes that can drive the initiation and evolution of CRC. Since in the last decade, crucial advances have been made concerning to the synergistic interaction among the TME and gut microorganisms that condition the identity of CCSC, the data exposed in this review could provide valuable insights into the biology of CRC and the development of new targeted therapies.

Cell Therapy as Target Therapy against Colon Cancer Stem Cells

Cancer stem cells (CSCs) are a small subpopulation of cells within tumors with properties, such as self-renewal, differentiation, and tumorigenicity. CSCs have been proposed as a plausible therapeutic target as they are responsible for tumor recurrence, metastasis, and conventional therapy resistance. Selectively targeting CSCs is a promising strategy to eliminate the propagation of tumor cells and impair overall tumor development. Recent research shows that several immune cells play a crucial role in regulating tumor cell proliferation by regulating different CSC maintenance or proliferation pathways. There have been great advances in cellular immunotherapy using T cells, natural killer (NK) cells, macrophages, or stem cells for the selective targeting of tumor cells or CSCs in colorectal cancer (CRC). This review summarizes the CRC molecular profiles that may benefit from said therapy and the main vehicles used in cell therapy against CSCs. We also discuss the challenges, limitations, and advantages of combining conventional and/or current targeted treatments in the late stages of CRC.

Cancer stem cells: Recent insights and therapies

Tumors are intricate ecosystems containing malignant components that generate adaptive and evolutionarily driven abnormal tissues. Through self-renewal and differentiation, cancers are reconstructed by a dynamic subset of stem-like cells that enforce tumor heterogeneity and remodel the tumor microenvironment (TME). Through recent technology advances, we are now better equipped to investigate the fundamental role of cancer stem cells (CSCs) in cancer biology. In this review, we discuss the latest insights into characteristics, markers and mechanism of CSCs and describe the crosstalk between CSCs and other cells in TME. Additionally, we explore the performance of single-cell sequencing and spatial transcriptome analysis in CSCs studies and summarize the therapeutic strategies to eliminate CSCs, which could broaden the understanding of CSCs and exploit for therapeutic benefit.

Targeting the tumor stroma for cancer therapy

Tumors are comprised of both cancer cells and surrounding stromal components. As an essential part of the tumor microenvironment, the tumor stroma is highly dynamic, heterogeneous and commonly tumor-type specific, and it mainly includes noncellular compositions such as the extracellular matrix and the unique cancer-associated vascular system as well as a wide variety of cellular components including activated cancer-associated fibroblasts, mesenchymal stromal cells, pericytes. All these elements operate with each other in a coordinated fashion and collectively promote cancer initiation, progression, metastasis and therapeutic resistance. Over the past few decades, numerous studies have been conducted to study the interaction and crosstalk between stromal components and neoplastic cells. Meanwhile, we have also witnessed an exponential increase in the investigation and recognition of the critical roles of tumor stroma in solid tumors. A series of clinical trials targeting the tumor stroma have been launched continually. In this review, we introduce and discuss current advances in the understanding of various stromal elements and their roles in cancers. We also elaborate on potential novel approaches for tumor-stroma-based therapeutic targeting, with the aim to promote the leap from bench to bedside.

Mechanisms of chemotherapeutic resistance and the application of targeted nanoparticles for enhanced chemotherapy in colorectal cancer

Colorectal cancer is considered one of the major malignancies that threaten the lives and health of people around the world. Patients with CRC are prone to post-operative local recurrence or metastasis, and some patients are advanced at the time of diagnosis and have no chance for complete surgical resection. These factors make chemotherapy an indispensable and important tool in treating CRC. However, the complex composition of the tumor microenvironment and the interaction of cellular and interstitial components constitute a tumor tissue with high cell density, dense extracellular matrix, and high osmotic pressure, inevitably preventing chemotherapeutic drugs from entering and acting on tumor cells. As a result, a novel drug carrier system with targeted nanoparticles has been applied to tumor therapy. It can change the physicochemical properties of drugs, facilitate the crossing of drug molecules through physiological and pathological tissue barriers, and increase the local concentration of nanomedicines at lesion sites. In addition to improving drug efficacy, targeted nanoparticles also reduce side effects, enabling safer and more effective disease diagnosis and treatment and improving bioavailability. In this review, we discuss the mechanisms by which infiltrating cells and other stromal components of the tumor microenvironment comprise barriers to chemotherapy in colorectal cancer. The research and application of targeted nanoparticles in CRC treatment are also classified.

3,4,5-O-tricaffeoylquinic acid with anti-radiation activity suppresses LPS-induced NLRP3 inflammasome activation via autophagy in THP-1 macrophages

Damage to normal tissues caused by excessive ionizing radiation (IR) exposure is the major side effect of radiotherapy. Several recent studies have shown that IR-induced damage to tissues leads to a systemic immune response and NLRP3 inflammasome activation in immune cells. 3,4,5-O-tricaffeoylquinic acid (tCQA), extracted from the natural plant Azolla imbricata, relieves inflammation and has radioprotective function. Here, we aimed to investigate the inhibitory effect and molecular mechanism of tCQA on IR-induced NLRP3 inflammasome activation. First, the results of ELISA and qPCR assays showed that tCQA has anti-inflammatory effects in THP-1 cell line and healthy human peripheral blood mononuclear cells. Western blotting and ELISA suggested tCQA could inhibit NF-κB/MAPK signaling pathway, NLRP3 expression and the secretion of IL-1β in lipopolysaccharide (LPS)-stimulated THP-1 macrophages. Then, flow cytometry, LDH assay and western blotting demonstrated that tCQA could inhibit LPS- and nigericin-induced Caspase-1 activation and gasdermin D cleavage, thereby suppressing inflammatory cell death. Furthermore, we found that the autophagy inhibitor chloroquine, not the proteasome inhibitor MG132, could counteract the promoting effect of tCQA on NLRP3 degradation and the inhibitory effect on cell death. Western blotting and autophagosome staining results suggested tCQA could significantly enhance LPS-induced autophagic flux in macrophages and ATG5/ATG7 knockdown reverses the inhibitory effect of tCQA on NLRP3 expression and Caspase-1 activation, indicating that tCQA induces NLRP3 degradation via autophagy. Finally, THP-1 macrophages and BALB/c mice were irradiated with ¹³⁷Cs γ-rays and tCQA could inhibit IR-induced NLRP3 inflammasome activation both in vitro and in vivo. To conclude, tCQA controls inflammation and NLRP3 inflammasome activation in vitro via NF-κB/MAPK signaling pathway and autophagy, meanwhile inhibits IR-induced NLRP3 inflammasome activation in vivo. Overall, our study provides an experimental and theoretical basis for the application of tCQA as a radioprotectant in clinical radiotherapy.

CXCL8 in Tumor Biology and Its Implications for Clinical Translation

The chemokine CXCL8 has been found to play an important role in tumor progression in recent years. CXCL8 activates multiple intracellular signaling pathways by binding to its receptors (CXCR1/2), and plays dual pro-tumorigenic roles in the tumor microenvironment (TME) including directly promoting tumor survival and affecting components of TME to indirectly facilitate tumor progression, which include facilitating tumor cell proliferation and epithelial-to-mesenchymal transition (EMT), pro-angiogenesis, and inhibit anti-tumor immunity. More recently, clinical trials indicate that CXCL8 can act as an independently predictive biomarker in patients receiving immune checkpoint inhibitions (ICIs) therapy. Preclinical studies also suggest that combined CXCL8 blockade and ICIs therapy can enhance the anti-tumor efficacy, and several clinical trials are being conducted to evaluate this therapy modality.

Stem cell therapy for COVID-19 pneumonia

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus is a highly contagious microorganism, and despite substantial investigation, no progress has been achieved in treating post-COVID complications. However, the virus has made various mutations and has spread around the world. Researchers have tried different treatments to reduce the side effects of the COVID-19 symptoms. One of the most common and effective treatments now used is steroid therapy to reduce the complications of this disease. Long-term steroid therapy for chronic inflammation following COVID-19 is harmful and increases the risk of secondary infection, and effective treatment remains challenging owing to fibrosis and severe inflammation and infection. Sometimes our immune system can severely damage ourselves in disease. In the past, many researchers have conducted various studies on the immunomodulatory properties of stem cells. This property of stem cells led them to modulate the immune system of autoimmune diseases like diabetes, multiple sclerosis, and Parkinson's. Because of their immunomodulatory properties, stem cell-based therapy employing mesenchymal or hematopoietic stem cells may be a viable alternative treatment option in some patients. By priming the immune system and providing cytokines, chemokines, and growth factors, stem cells can be employed to build a long-term regenerative and protective response. This review addresses the latest trends and rapid progress in stem cell treatment for Acute Respiratory Distress Syndrome (ARDS) following COVID-19.

The role of mesenchymal stem cells in the occurrence, development, and therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of liver malignant tumor, with high recurrence and mortality rates. Mesenchymal stem cells (MSCs) are multipotent cells that can be recruited into the tumor microenvironment (TME). What is known, TME plays a vital part in tumor progression. In recent years, accumulating studies have found that MSCs have a dual role of promotion and inhibition in the occurrence and development of HCC. In this review, we analyzed the role of MSCs in TME and summarized the relationship between MSCs and liver cancer stem cells, the molecular signaling pathway mechanisms of MSCs promoting and inhibiting HCC, and the latest research progress of MSCs in the treatment of HCC.

Importance of the origin of mesenchymal (stem) stromal cells in cancer biology: "alliance" or "war" in intercellular signals

Mesenchymal stem cells (MSCs) play a central role in the intercellular signaling within the tumor microenvironment (TME), exchanging signals with cancer cells and tumor stromal cells, such as cancer-associated fibroblasts and inflammatory mononuclear cells. Research attributes both pro-tumor and anti-tumor actions to MSCs; however, evidence indicates that MSCs specific effect on the tumor depends on the source of the MSCs and the type of tumor. There are consistent data proving that MSCs from reproductive tissues, such as the uterus, umbilical cord or placenta, have potent anti-tumor effects and tropism towards tumor tissues. More interestingly, products derived from MSCs, such as secretome or extracellular vesicles, seem to reproduce the effects of their parental cells, showing a potential advantage for clinical treatments by avoiding the drawbacks associated with cell therapy. Given these perspectives, it appears necessary new research to optimize the production, safety and antitumor potency of the products derived from the MSCs suitable for oncological therapies.

The Use of Iron Oxide Nanoparticles to Reprogram Macrophage Responses and the Immunological Tumor Microenvironment

The synthesis and functionalization of iron oxide nanoparticles (IONPs) is versatile, which has enhanced the interest in studying them as theranostic agents over recent years. As IONPs begin to be used for different biomedical applications, it is important to know how they affect the immune system and its different cell types, especially their interaction with the macrophages that are involved in their clearance. How immune cells respond to therapeutic interventions can condition the systemic and local tissue response, and hence, the final therapeutic outcome. Thus, it is fundamental to understand the effects that IONPs have on the immune response, especially in cancer immunotherapy. The biological effects of IONPs may be the result of intrinsic features of their iron oxide core, inducing reactive oxygen species (ROS) and modulating intracellular redox and iron metabolism. Alternatively, their effects are driven by the nanoparticle coating, for example, through cell membrane receptor engagement. Indeed, exploiting these properties of IONPs could lead to the development of innovative therapies. In this review, after a presentation of the elements that make up the tumor immunological microenvironment, we will review and discuss what is currently known about the immunomodulatory mechanisms triggered by IONPs, mainly focusing on macrophage polarization and reprogramming. Consequently, we will discuss the implications of these findings in the context of plausible therapeutic scenarios for cancer immunotherapy.

IL-8/CXCR2 mediates tropism of human bone marrow-derived mesenchymal stem cells toward CD133+ /CD44+ Colon cancer stem cells

In cancer treatment, the most attractive feature of mesenchymal stem cells (MSCs) is it's homing to tumor tissues. MSC is an important part of the "colon cancer stem cell niche", but little research has been done on the tropism of human MSCs toward colon cancer stem cells (CCSCs). In this study, we first compared the effects of three tissue-derived MSCs (bone marrow, adipose tissue, and placenta) in vivo on colon tumor xenograft growth. Then, we analyzed the tropism of bone marrow-derived MSCs (BMSCs) toward normal intestinal epithelial cells (NCM460), parental colon cancer cells, CD133- /CD44-, and CD133+ /CD44+ colon cancer cells in vitro. Microarray analysis and in vitro experiments explored the mechanism of mediating the homing of BMSCs toward CCSCs. Compared with the parental and CD133- /CD44- colon cancer cells, CD133+ /CD44+ cells have a stronger ability to recruit BMSCs. In addition, BMSCs were significantly transformed into cancer-associated fibroblasts after being recruited by CCSCs. After coculture of BMSCs and CCSCs, the expression of interleukin (IL)-6, IL-8, IL-32, and CCL20 was significantly increased. Compared with parental strains, CD133- /CD44- cells, and NCM460, BMSC secreted significantly more IL-8 after coculture with CD133+ /CD44+ cells. Low concentration of IL-8 peptide inhibitors (100 ng/ml) and CXC receptor 2 (CXCR2) inhibitors have little effect on the migration of BMSCs, but can effectively weaken CCSC stemness and promote dormant CSCs in the coculture system to re-enter into the cell cycle. The endogenous IL-8 knockout in BMSCs or BMSCs loaded with IL-8 and/or CXCR2 inhibitors will make the therapy of BMSC targeting CCSCs function at its best.

Targeting stemness of cancer stem cells to fight colorectal cancers

Cancer initiating/ stem cells (CSCs) undergo self-renewal and differentiation that contributes to tumor initiation, recurrence and metastasis in colorectal cancer (CRC). Targeting of colorectal cancer stem cells (CCSCs) holds significant promise in eradicating cancer cells and ultimately curing patients with cancer. In this review, we will introduce the current progress of CCSC studies, including the specific surface markers of CCSCs, the intrinsic signaling pathways that regulate the stemness and differentiation characteristics of CCSCs, and the tumor organoid model for CCSC research. We will focus on how these studies will lead to the progress in targeting specific surface markers or signaling pathways on CCSCs by monoclonal antibodies, or by natural or synthetic compounds, or by immunotherapy. As CSCs are highly heterogeneous and plastic, we suggest that combinatory approaches that target the stemness network may represent an important strategy for eradicating cancers.