Epithelial-mesenchymal transition in cancer stemness and heterogeneity: updated

Exosomes in bridging macrophage-fibroblast polarity and cancer stemness

Exosome roles in cellular cross-talking within tumor microenvironment (TME) is a critical event in tumorigenesis. Type 2 macrophages (M2), cancer-associated fibroblasts (CAFs) and cancer stem cells (CSCs) are the three most important cells in cancer progression and metastasis, and targeting their connectome route can be an effective anti-cancer strategy. Exosomes mediate bidirectional cross-talking between the three cell types in which exosomes secreted from CSCs promote polarization of M2 macrophages and CAFs, and that M2- and CAF-derived exosomes promote cancer stemness through activation of epithelial-mesenchymal transition (EMT)-related signaling including transforming growth factor (TGF)-β, WNT/β-catenin and epidermal growth factor (EGF). CSC-derived exosomal TGF-β is a key driver of CAF and M2 macrophage polarization, with the latter mediated through activation of signal transducer and activator of transcription 3 (STAT3). β-catenin activity also seems to take important role in exosomal cross-talk between CAFs and stemness state of cancer. Incubation of exosomes with inhibitors of signaling inter-connecting CSCs, M2 and CAFs is a key anti-cancer strategy and a promising supplementary to the routine immunotherapeutic approaches in cancer therapy.

Mechanism of miR-200b-3p-induced FOSL2 inhibition of endometrial cancer cell proliferation and metastasis

The purpose of this study was to investigate how miR-200b-3p inhibits the proliferation and metastasis of endometrial cancer cells by inducing the expression of FOSL2 in the AP1 transcription family. Endometrial cancer cell line HEC-1-A was divided into 16 groups: NC-mimic (transfected with negative control NC mimic), miR-200b-3p mimic (transfected with miR-200b-3p mimic), NC-suppress (transfected with negative control NC inhibit), miR-200b-3p inhibit group (transfected with miR-200b-3p inhibit), si-NC (transfected with negative control si-NC), si-FOSL2 (transfected with Si-FOSL2), oe-NC (transfected with negative control oe-NC), oe-FOSL2 group (oe-FOSL2), miR-200b-3p mimic + oe-NC group (co-transfected with miR-200b-3p mimic and oe-NC), miR-200b-3p mimic + oe-FOSL2 group (co-transfected with miR-200b-3p mimic and oe-FOSL2), miR-200b-3p inhibit + si-NC group (co-transfected with miR-200b-3p inhibit and si-NC), miR-200b-3p inhibit + si-FOSL2 group (co-transfected with miR-200b-3p inhibit and si-FOSL2), miR-200b-3p mimic + si-NC group (co-transfected with miR-200b-3p mimic and si-NC), miR-200b-3p mimic + si-FOSL2 group (co-transfected with miR-200b-3p mimic and si-FOSL2), miR-200b-3p inhibit + oe-NC group (co-transfected with miR-200b-3p inhibit and oe-NC), miR-200b-3p inhibit + oe-FOSL2 group (co-transfected with miR-200b-3p inhibit and oe-FOSL2). Real-time fluorescence quantitative PCR, Western blot, CCK-8 assay, scratch test and Transwell assay were used to detect the expression of miR-200b-3p mRNA, FOSL2 mRNA and protein, cell proliferation, migration and invasion. In endometrial cancer cell lines, the expression of miR-200b-3p was significantly down-regulated (P < 0.05), while the expression of FOSL2 was significantly up-regulated (P < 0.05). Compared with NC-mimic group, the expression of FOSL2, N-cadherin and Vimentin in miR-200b-3p mimic group was significantly decreased (P < 0.05), and the expression of E-cadherin was significantly increased (P < 0.05). The cell proliferation, migration rate and the number of transmembrane cells were significantly decreased (P < 0.05). Compared with the miR-200b-3p mimic + oe-NC group, the expression of FOSL2, N-cadherin and Vimentin in miR-200b-3p mimic + oe-FOSL2 was significantly increased (P < 0.05), the expression level of E-cadherin was significantly decreased (P < 0.05), and the cell proliferation, migration rate and the number of transmembrane cells were significantly increased (P < 0.05). Compared with NC-inhibit group, the expression of FOSL2, N-cadherin and Vimentin in miR-200b-3p inhibit group was significantly increased (P < 0.05), and the expression of E-cadherin was significantly decreased (P < 0.05). The cell proliferation, migration rate and the number of transmembrane cells were significantly increased (P < 0.05). Compared with the miR-200b-3p inhibit + si-NC group, the expression of FOSL2, N-cadherin and Vimentin in miR-200b-3p inhibit + si-FOSL2 was significantly decreased (P < 0.05), and the expression of E-cadherin was significantly increased (P < 0.05); the cell proliferation, migration rate and the number of transmembrane cells were significantly decreased (P < 0.05) The expression of miR-200b-3p in endometrial cancer cells is down-regulated, which can inhibit the proliferation, migration and invasion of endometrial cancer cells by regulating the EMT process, and its mechanism is related to its targeted negative regulation of FOSL2 expression.

The Importance of Cancer Stem Cells and Their Pathways in Endometrial Cancer: A Narrative Review

Endometrial cancer is one of the most common malignancies seen in women in developed countries. While patients in the early stages of this cancer show better responses to surgery, adjuvant hormonal therapy, and chemotherapy, patients with recurrence show treatment resistance. Researchers have recently focused on cancer stem cells (CSCs) in the treatment of gynecologic cancer in general but also specifically in endometrial cancer. CSCs have been investigated because of their resistance to conventional therapies, such as chemo- and radiotherapy, and their ability to induce the progression and recurrence of malignancy. The activation of alternative pathways, such as WNT, PI3K, NF-kB, or NOTCH, could be the basis of the acquisition of these abilities of CSCs. Their specific markers and signaling pathways could be treatment targets for CSCs. In this article, we discuss the importance of obtaining a better understanding of the molecular basis and pathways of CSCs in endometrial cancer and the role of CSCs, aiming to discover more specific therapeutic approaches.

Hypoxic Cancer Cells-Derived Exosomes Strengthen the Development of Cancer Stem Cell-Like Properties Through Delivering LINC00665 in Thyroid Cancer Cells

Hypoxia is a common phenomenon for solid tumors due to a lack of effective vascular system, and has been deemed as an important factor that drives the progression of thyroid cancer (TC) via altering the characteristics of tumor cells. The present study suggested that hypoxic TC cells enhanced cancer stem cell properties and progression of TC by delivering long intergenic non-protein coding RNA 665 (LINC00665)-containing exosomes. Specifically, TPC1 cells were exposed to normoxic or hypoxic environment, and it was found that hypoxic TPC1 cells-secreted exosomes (H-exo) were enriched with LINC00665, compared to normoxic TPC1 cells-derived exosomes (N-exo). In addition, by establishing the in vitro exosomes-TC cells coculture system, we found that in contrast to N-exo, H-exo apparently promoted cell proliferation, epithelial mesenchymal transition (EMT) and cancer stem cell properties via delivering LINC00665. This was supported by the in vivo results that H-exo transferred LINC00665 to promote tumorigenesis and the expression of EMT and stemness-associated markers in xenograft tumor-bearing mice models. Further mechanical experiments validated that LINC00665 combined with EPHB4 mRNA to sustain its stability to enhance cancer aggressiveness of TC. Altogether, our findings verified that hypoxic TC cells-secreted exosomes regulated the LINC00665/EPHB4 axis to enhance cancer stem cell properties of TC, providing novel signatures for TC diagnosis and therapy.

Tiny messengers, big Impact: Exosomes driving EMT in oral cancer

Exosomes are indispensable extracellular vesicles that facilitate intercellular communication and are crucial for both healthy and pathological conditions, including cancer. The capacity of exosomes to echo the molecular characteristics of their cells of origin, including malignant cells, makes them indispensable tools for diagnosing and tracking disease progression in the field of oncology. Oral squamous cell carcinoma (OSCC), which has been identified as the sixth most prevalent cancer worldwide, has been linked to numerous risk factors, including tobacco use, alcohol consumption, human papillomavirus (HPV) infection, and inadequate oral hygiene. Exosomes pointedly influence the advancement of oral cancer via promoting tumor cell growth, invasion, angiogenesis, and immune evasion through the alteration of the tumor microenvironment. A critical apparatus in cancer metastasis is the epithelial-to-mesenchymal transition (EMT), during which cancer cells acquire improved migratory and invasive properties. EMT plays a role in metastasis, resistance to treatment, and evasion of the immune response. Exosomes facilitate EMT in oral cancer by delivering bioactive molecules that influence EMT signaling pathways. These exosomes inspire EMT in recipient cells, by this means enhancing tumor invasion and metastasis. This study aims to identify the specific exosomal components and signaling pathways that are tangled in EMT, in that way providing new avenues for targeted therapies designed to hinder the metastasis of oral cancer.

Natural Bioactive Agents: Testable Stem Cell-Targeting Alternatives for Therapy-Resistant Breast Cancer

Long-term treatment options for conventional chemo-endocrine therapy and molecular-pathway-based targeted therapy are associated with acquired therapy resistance and the emergence of drug-resistant cancer-initiating stem cell populations, leading to the progression of metastatic disease. These treatment options are based on the expression status of estrogen receptor-α (ER-α), progesterone receptor (PR) hormone receptors, and/or of human epidermal growth factor receptor-2 (HER-2). The breast cancer subtypes Luminal A, Luminal B, and HER-2-enriched express hormone/growth factor receptors and exhibit a favorable response to hormone receptor modulators and growth factor receptor antagonists. The triple-negative breast cancer subtype lacks the expression of hormone/growth factor receptors and responds only to cytotoxic conventional chemotherapy. The clinical limitations, due to the modest therapeutic responses of chemo-resistant cancer-initiating stem cells, emphasize the need for the identification of stem cells targeting testable alternatives for therapy-resistant breast cancer. Developed drug-resistant stem cell models exhibit upregulated expression of select cellular biomarker tumor spheroid (TS) formations and cluster of differentiation44 (CD44), DNA-binding protein (NANOG), and octamer-binding protein-4 (OCT-4) molecular biomarkers that represent novel experimentally modifiable quantitative endpoints. Naturally occurring dietary phytochemicals and nutritional herbs containing polyphenols, flavones, terpenes, saponins, lignans, and tannins have documented human consumption, lack systemic toxicity, lack phenotypic drug resistance, and exhibit preclinical efficacy. Constituent bioactive agents may provide testable stem cell-targeting alternatives. The present report provides an overview of (i) clinically relevant cellular models and drug-resistant cancer stem cell models for breast cancer subtypes, (ii) evidence for preclinical efficacy and mechanistic leads for natural phytochemicals and nutritional herbs, and (iii) the potential for the stem cell-targeting efficacy of natural bioactive agents as testable drug candidates for therapy-resistant breast cancer.

Metabolic reprogramming and therapeutic resistance in primary and metastatic breast cancer

Metabolic alterations, a hallmark of cancer, enable tumor cells to adapt to their environment by modulating glucose, lipid, and amino acid metabolism, which fuels rapid growth and contributes to treatment resistance. In primary breast cancer, metabolic shifts such as the Warburg effect and enhanced lipid synthesis are closely linked to chemotherapy failure. Similarly, metastatic lesions often display distinct metabolic profiles that not only sustain tumor growth but also confer resistance to targeted therapies and immunotherapies. The review emphasizes two major aspects: the mechanisms driving metabolic resistance in both primary and metastatic breast cancer, and how the unique metabolic environments in metastatic sites further complicate treatment. By targeting distinct metabolic vulnerabilities at both the primary and metastatic stages, new strategies could improve the efficacy of existing therapies and provide better outcomes for breast cancer patients.

Integrated analysis to identify biological features and molecular markers of poorly cohesive gastric carcinoma (PCC)

As one of the two main histologic subtypes of gastric cancer (GC), diffuse-type gastric cancer (DGC) containing poorly cohesive gastric carcinoma (PCC) components has a worse prognosis and does not respond well to typical therapies. Despite the large number of studies revealing the complex pathogenic network of DGC, the molecular heterogeneity of DGC is still not fully understood. We obtained single-cell RNA-seq data and bulk data from the tumor immune single cell hub, the public gene expression omnibus, and the cancer genome atlas databases. A series of bioinformatics analyses were performed using R software. Immunofluorescence staining, hematoxylin and eosin staining, western blot, and functional experiments were used for experimental validation. Caudin-3, -4 and -7 were lowly expressed in DGC and their expression levels were further reduced in PCC. The PCC components were mainly located in the deeper layers of the DGC and had a high level of hypoxic Wnt/β-catenin signaling and stemness. We further identified Insulin Like Growth Factor Binding Protein 7 (IGFBP7) as a marker for PCC components in the deep layer. IGFBP7 is stimulated by hypoxia and promotes cancer cell invasiveness and reduced claudin expression. In addition, programmed death-1 ligand (PD-L1) was specifically expressed in the deep layer, reflecting deep layer-specific immunosuppression. The PCC components are predominantly situated in the deeper layers of DGC. Initial molecular characterization of these PCC components revealed distinct features, including low expression of claudin-3, -4, and -7, high expression of IGFBP7, and the presence of PD-L1. These molecular traits may partially account for the pronounced tumor heterogeneity observed in GC.

Generation of novel lipid metabolism-based signatures to predict prognosis and immunotherapy response for colorectal adenocarcinoma

Lipid metabolism reprogramming involves in epithelial-mesenchymal transition (EMT), cancer stemness and immune checkpoints (ICs), which influence the metastasis of cancer. This study aimed to generate lipid metabolism-based signatures to predict prognosis, immunotherapy and chemotherapy response for colorectal adenocarcinoma (COAD). Transcriptome data and clinical information of COAD patients were collected from the cancer genome atlas (TCGA) database. The expression of EMT-, stem cell-, and IC-related genes were assessed between COAD and control samples. Modules and genes correlated EMT, ICs and stemness signatures were identified through weighted gene co-expression network analysis (WGCNA). Prognostic signatures were generated and then the distribution of risk genes was evaluated using single-cell RNA sequencing (scRNA-seq) data from GSE132465 dataset. COAD patients exhibited increased EMT score and stemness along with decreased ICs. Next, 12 hub genes (PIK3CG, ALOX5AP, PIK3R5, TNFAIP8L2, DPEP2, PIK3CD, PIK3R6, GGT5, ELOVL4, PTGIS, CYP7B1 and PRKD1) were found within green and yellow modules correlated with EMT, stemness and ICs. Lipid metabolism-based prognostic signatures were generated based on PIK3CG, GGT5 and PTGIS. Patients with high-risk group had poor prognosis, elevated ESTIMATEScore and StromalScore, 100% mutation rate and higher TIDE score. Samples in low-risk group had more immunogenicity on ICIs. Notably, PIK3CG was expressed in B cells, while GGT5 and PTGIS were expressed in stromal cells. This study generates lipid metabolism-based signatures correlated with EMT, stemness and ICs for predicting prognosis of COAD, and provides potential therapeutic targets for immunotherapy in COAD.

Research Progress on the Anti-Cancer Effects of Astragalus membranaceus Saponins and Their Mechanisms of Action

Astragalus membranaceus saponins are the main components of A. membranaceus, a plant widely used in traditional Chinese medicine. Recently, research on the anti-cancer effects of A. membranaceus saponins has received increasing attention. Numerous in vitro and in vivo experimental data indicate that A. membranaceus saponins exhibit significant anti-cancer effects through multiple mechanisms, especially in inhibiting tumor cell proliferation, migration, invasion, and induction of apoptosis, etc. This review compiles relevant studies on the anti-cancer properties of A. membranaceus saponins from various databases over the past two decades. It introduces the mechanism of action of astragalosides, highlighting their therapeutic benefits in the management of cancer. Finally, the urgent problems in the research process are highlighted to promote A. membranaceus saponins as an effective drug against cancer.

FOXP2 inhibits the aggressiveness of lung cancer cells by blocking TGFβ signaling

Lung cancer is associated with high morbidity and mortality rates. Forkhead box P2 (FOXP2) functions as an antitumor gene in various cancers. However, its role in lung cancer remains to be elucidated. The present study explored the potential role of FOXP2 in lung cancer. mRNA levels and protein expression were determined using RT-qPCR and western blotting, respectively. Functional analysis was performed using the CCK-8, Transwell and TUNEL assays. FOXP2 expression was downregulated in lung cancer. Notably, FOXP2 suppressed the proliferative, migratory and invasive abilities of lung cancer cells and promoted tumor cell apoptosis. In addition, FOXP2 blocked TGFβ signaling. However, SRI-011381-stimulated activation of TGFβ signaling reversed the effects of overexpressed FOXP2 and promoted the aggressiveness of lung cancer cells. FOXP2 functions as an antitumor gene in lung cancer cells. FOXP2 suppressed the malignant behavior of lung cancer by inactivating TGFβ signaling.

Identification of estrogen response-associated STRA6+ granulosa cells within high-grade serous ovarian carcinoma by single-cell sequencing

Background

High-grade serous ovarian carcinoma (HGSOC) is a pathologic subtype of ovarian cancer (OC) with a more lethal prognosis. Extensive heterogeneity results in HGSOC being more susceptible to treatment resistance and adverse treatment effects. Revealing the heterogeneity involved is crucial.

Methods

We downloaded the single-cell RNA-seq (scRNA) data from GEO database and performed a scRNA analysis for cell landscape of HGSOC by using the Seurat package. The highly expressed genes were uploaded into the DAVID and KEGG database for enrichment analysis, and the AUCell package was used to calculate cancer-associated hallmark score. The SCENIC analysis was used for key regulons, the estrogen response enrichment scores in TCGA-OV RNA-seq dataset were calculated by using the GSVA package. Besides, the expression of STRA6 and IRF1 and the cell invasion and migration in si-STRA6 OC cells were detected by using the quantitative reverse transcription (qRT)-PCR method and Transwell assay respectively.

Results

We successfully constructed a single-cell atlas of HGSOC and delineated the heterogeneity of epithelial cells therein. There were five epithelial cell subpopulations, GLDC + Epithelial cells, PEG3+ leydig cells, STRA6+ granulosa cells, POLE2+ Epithelial cells, and AURKA + Epithelial cells. STRA6+ granulosa cells have the potential to promote tumor growth as well as the highest estrogen response early activity through the biological pathways analysis of highly expressed genes and estrogen response score of ssGSEA. We found that IRF1 and STRA6 expression was remarkably upregulated in the OC cancer cell line HEY. Silencing of STRA6 markedly decreased the invasion and migration ability of the OC cancer cell line HEY.

Conclusion

There is extreme heterogeneity of epithelial cells in HGSOC, and STRA6+ granulosa cells may be able to promote cancer progression. Our findings are benefit to the heterogeneity identification of HGSOC and develop targeted therapy strategy for HGSOC patients.

E-CADERIN, N-CADERIN, SLUG, SNAIL, and TWIST contribute to epithelial-mesenchymal transition in salivary gland tumors

BACKGROUND

Transcription factors are important in the epithelial-mesenchymal transition process and are possibly related to the development of a more invasive tumor phenotype. Thus, the objective of this study was to analyze the expression and identify the localization of cellular markers related to the epithelial-mesenchymal transition process in salivary gland tumors.

STUDY DESIGN

The expression and localization of E-CADERIN, N-CADERIN, SLUG, SNAIL, and TWIST were evaluated, using immunohistochemistry, in 48 salivary gland tumors, being 17 pleomorphic adenomas (PA), 14 adenoid cystic carcinomas (ACC), and 17 mucoepidermoid carcinomas (MEC). these proteins were compared to clinical and histopathologic parameters. normal gland tissues were included for immunohistochemical comparisons.

RESULTS

ACC and MEC cases showed higher expression of SNAIL compared to PA. MEC showed high expression of SLUG and TWIST. Low expression of N-CADHERIN, SNAIL, and TWIST in ACC was frequent in T3 and T4. High expression of TWIST in MEC was more frequent at age ≥ 40 years A positive correlation was only observed between N-cadherin/SNAIL in ACC, between SNAIL/TWIST in MEC, and between SLUG/TWIST in PA.

CONCLUSION

This study provided insight into EMT-related proteins (E-cadherin, N-cadherin, SNAIL, SLUG, and TWIST) and their contribution to the maintenance of morphogenesis and the development of the salivary gland tumors and showed a positive correlation among N-CADHERIN/SNAIL in ACC and SNAIL/TWIST in MEC.

USP10 promotes intrahepatic cholangiocarcinoma cell survival and stemness via SNAI1 deubiquitination

Cancer cell stemness contributes significantly to intrahepatic cholangiocarcinoma (ICC) progression. However, the roles of deubiquitinating enzymes (DUBs) in ICC modulation are poorly understood. Ubiquitin specific peptidase 10 (USP10) was highly expressed in ICC spheres. The interaction between USP10 and snail family transcriptional repressor 1 (SNAI1) reduced the polyubiquitination of the SNAI1 protein and stabilized the SNAI1 protein. USP10 knockdown in RBE cells inhibited cell proliferation, promoted cell apoptosis and decreased the diameter of the formed spheres and the expression levels of CD44, EpCAM, OCT4 and SOX2. SNAI1 overexpression alleviated the effect of USP10 knockdown in RBE cells. In addition, the knockdown of USP10 attenuated the ability of RBE cells to form tumors subcutaneously in nude mice. Our results revealed that USP10 attenuates ICC cell malignancy by deubiquitinating SNAI1, indicating that USP10 could be developed as a therapeutic target for ICC treatment.

Alternative immune checkpoints in immunoregulatory profile of cancer stem cells

Tumor-mediated bypass of immune checkpoint inhibitor (ICI) therapy with anti-programmed death-1 (PD-1), anti-programmed death-ligand 1 (PD-L1, also called B7-H1 or CD274) or anti-cytotoxic T lymphocyte associated antigen-4 (CTLA-4) is a challenge of current years in the area of cancer immunotherapy. Alternative immune checkpoints (AICs) are molecules beyond the common PD-1, PD-L1 or CTLA-4, and are upregulated in patients who show low/no ICI responses. These are members of B7 family including B7-H2 (ICOS-L), B7-H3 (CD276), B7-H4 (B7x), V-domain immunoglobulin suppressor of T cell activation (VISTA), B7-H6, HHLA2 (B7-H5/B7-H7) and catabolic enzymes like indoleamine 2,3-dioxygenase 1 (IDO1), and others that are also contributed to the regulation of tumor immune microenvironment (TIME). There is also strong evidence supporting the implication of AICs in regulation of cancer stemness and expanding the population of cancer stem cells (CSCs). CSCs display immunoregulatory capacity and represent multiple immune checkpoints either on their surface or inside. Besides, they are active promoters of resistance to the common ICIs. The aim of this review is to investigate interrelations between AICs with stemness and differentiation profile of cancer. The key message of this paper is that targeted checkpoints can be selected based on their impact on CSCs along with their effect on immune cells. Studies published so far mainly focused on immune cells as a target for anti-checkpoints. Ex vivo engineering of extracellular vesicles (EVs) equipped with CSC-targeted anti-checkpoint antibodies is without a doubt a key therapeutic target that can be under consideration in future research.

Dual anti-PD-(L)1/TGF-β inhibitors in cancer immunotherapy - Updated

Immune checkpoint inhibitor (ICI) therapy suffers from tumor resistance and relapse in majority of patients due to the suppressive tumor immune microenvironment (TIME). Advances in the field have brought about development of fusion proteins able to target two signaling simultaneously and to exert maximal anti-cancer immunity. Bispecific inhibitors of transforming growth factor (TGF)-β signaling and programmed death-1 (PD-1) or programmed death-ligand 1 (PD-L1) are developed to reduce the rate of relapse and to achieve durable anti-cancer therapy. TGF-β is well-known for its immunosuppressive activity, and it takes critical roles in promotion of all tumor hallmarks. Bispecific anti-PD-(L)1/TGF-β inhibitors reinvigorate effector activity of CD8+ T and natural killer (NK) cells, hamper regulatory T cell (Treg) expansion, and increase the density of anti-tumor type 1 macrophages (M1). Responses to the bispecific approach are higher compared with solo anti-PD-(L)1 or TGF-β targeted therapy, and are seemingly more pronounced in human papillomavirus (HPV)+ patients. High expression of PD-L1 or immune-excluded phenotype in a tumor can also be markers of better response to the bispecific strategy. Besides, anti-PD-(L)1/TGF-β inhibitor therapy can be used safely with other therapeutic modalities including vaccination, radiation and chemotherapy.

Understanding human aging and the fundamental cell signaling link in age-related diseases: the middle-aging hypovascularity hypoxia hypothesis

Aging-related hypoxia, oxidative stress, and inflammation pathophysiology are closely associated with human age-related carcinogenesis and chronic diseases. However, the connection between hypoxia and hormonal cell signaling pathways is unclear, but such human age-related comorbid diseases do coincide with the middle-aging period of declining sex hormonal signaling. This scoping review evaluates the relevant interdisciplinary evidence to assess the systems biology of function, regulation, and homeostasis in order to discern and decipher the etiology of the connection between hypoxia and hormonal signaling in human age-related comorbid diseases. The hypothesis charts the accumulating evidence to support the development of a hypoxic milieu and oxidative stress-inflammation pathophysiology in middle-aged individuals, as well as the induction of amyloidosis, autophagy, and epithelial-to-mesenchymal transition in aging-related degeneration. Taken together, this new approach and strategy can provide the clarity of concepts and patterns to determine the causes of declining vascularity hemodynamics (blood flow) and physiological oxygenation perfusion (oxygen bioavailability) in relation to oxygen homeostasis and vascularity that cause hypoxia (hypovascularity hypoxia). The middle-aging hypovascularity hypoxia hypothesis could provide the mechanistic interface connecting the endocrine, nitric oxide, and oxygen homeostasis signaling that is closely linked to the progressive conditions of degenerative hypertrophy, atrophy, fibrosis, and neoplasm. An in-depth understanding of these intrinsic biological processes of the developing middle-aged hypoxia could provide potential new strategies for time-dependent therapies in maintaining healthspan for healthy lifestyle aging, medical cost savings, and health system sustainability.

The impact of hypoxia on tumor-mediated bypassing anti-PD-(L)1 therapy

Extending the durability of response is the current focus in cancer immunotherapy with immune checkpoint inhibitors (ICIs). However, factors like non-immunogenic tumor microenvironment (TME) along with aberrant angiogenesis and dysregulated metabolic systems are negative contributors. Hypoxia is a key TME condition and a critical promoter of tumor hallmarks. It acts on immune and non-immune cells within TME in order for promoting immune evasion and therapy resistance. Extreme hypoxia is a major promoter of resistance to the programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor therapy. Hypoxia inducible factor-1 (HIF-1) acts as a key mediator of hypoxia and a critical promoter of resistance to the anti-PD-(L)1. Targeting hypoxia or HIF-1 can thus be an effective strategy for reinvigoration of cellular immunity against cancer. Among various strategies presented so far, the key focus is over vascular normalization, which is an approach highly effective for reducing the rate of hypoxia, increasing drug delivery into the tumor area, and boosting the efficacy of anti-PD-(L)1.

Fatty Acid Metabolites and the Tumor Microenvironment as Potent Regulators of Cancer Stem Cell Signaling

Individual cancer cells are not equal but are organized into a cellular hierarchy in which only a rare few leukemia cells can self-renew in a manner reminiscent of the characteristic stem cell properties. The PI3K/AKT pathway functions in a variety of cancers and plays a critical role in the survival and proliferation of healthy cells under physiologic conditions. In addition, cancer stem cells might exhibit a variety of metabolic reprogramming phenotypes that cannot be completely attributed to the intrinsic heterogeneity of cancer. Given the heterogeneity of cancer stem cells, new strategies with single-cell resolution will become a powerful tool to eradicate the aggressive cell population harboring cancer stem cell phenotypes. Here, this article will provide an overview of the most important signaling pathways of cancer stem cells regarding their relevance to the tumor microenvironment and fatty acid metabolism, suggesting valuable strategies among cancer immunotherapies to inhibit the recurrence of tumors.

Pleiotropic Signaling by Reactive Oxygen Species Concerted with Dietary Phytochemicals and Microbial-Derived Metabolites as Potent Therapeutic Regulators of the Tumor Microenvironment

The excessive generation of reactive oxygen species (ROS) plays a pivotal role in the pathogenesis of diseases. ROS are central to cellular redox regulation and act as second messengers to activate redox-sensitive signals. Recent studies have revealed that certain sources of ROS can be beneficial or harmful to human health. Considering the essential and pleiotropic roles of ROS in basic physiological functions, future therapeutics should be designed to modulate the redox state. Dietary phytochemicals, microbiota, and metabolites derived from them can be expected to be developed as drugs to prevent or treat disorders in the tumor microenvironment.

The impact of hypoxia on extracellular vesicle secretome profile of cancer

Extracellular vesicles (EVs) are emerging as key mediators of cell-to-cell communications and signal transporters between tumor and stroma, and hypoxia is a critical characteristic of tumor microenvironment (TME) in solid cancers. Hypoxia stimulates tumor cells to generate and secrete more EVs, and the EVs shed from cancer transfer biological information to boost hypoxia and hypoxia inducible factor (HIF) functionality. Hypoxia alters EV secretome profile to carry pro-tumorigenic factors for promoting numerous tumor-related processes including increased cancer cell proliferation and survival, immune escape, aberrant angiogenesis, and invasion and metastasis. Exosomal hypoxia inducible factor (HIF)-1α is an essential driver of epithelial-mesenchymal transition (EMT) and stemness profile in cancer. Hypoxic cancer-derived EVs are also contributed to therapy resistance. In fact, EVs are messengers of hypoxic tolerance in cancer, which enable adaptation of tumor cells to changes occurring within TME for their further resistance and metastasis. Tracing EVs shed from hypoxic tumor cells into plasma provide important information about the genomic signature of cancer. In this review, we aimed to discuss about key tumorigenic events promoted by inter-connections between hypoxia and EVs, mainly exosomes, secreted into tumor area focusing on key hallmarks of cancer.

FAK downregulation suppresses stem-like properties and migration of human colorectal cancer cells

Focal adhesion kinase (FAK) is a cytoplasmic protein tyrosine kinase, which is overexpressed in colorectal cancer cells. FAK could be activated by phosphorylation to participate in the transduction of multiple signaling pathways and self-renewal of cancer stem cells. Whether the downregulation of FAK inhibits the metastasis in colorectal cancer through the weakening of stem cell-like properties and its mechanisms has yet to be established. CD44, CD133, c-Myc, Nanog, and OCT4 were known to mark colorectal cancer stem cell properties. In this study, AKT inhibitor (MK-2206 2HCl) or FAK inhibitor (PF-562271) decreased the expression of stem cell markers (Nanog, OCT4, CD133, CD44, c-Myc) and spheroid formation in colorectal cancer. Moreover, FAK and AKT protein was shown to interact verified by co-immunoprecipitation. Furthermore, downregulation of FAK, transfected Lenti-FAK-EGFP-miR to colorectal cancer cells, reduced p-AKT but not AKT and decreased the expression of stem cell markers and spheroid formation in colorectal cancer. In conclusion, we demonstrated that downregulation of FAK inhibited stem cell-like properties and migration of colorectal cancer cells partly due to altered modulation of AKT phosphorylation by FAK.

A Signaling Crosstalk Links SNAIL to the 37/67 kDa Laminin-1 Receptor Ribosomal Protein SA and Regulates the Acquisition of a Cancer Stem Cell Molecular Signature in U87 Glioblastoma Neurospheres

Background: Three-dimensional in vitro neurospheres cultures recapitulate stemness features associated with poor clinical outcome in glioblastoma patients. They are commonly used to address brain cancer stem cell (CSC) signal transducing biology that regulates spheroids formation and stemness phenotype, and to assess the in vitro pharmacological impact of chemotherapeutic drugs. Objective: Here, we addressed the role of a new signaling axis involved in the regulation of in vitro spheroids formation and assessed the chemopreventive ability of diet-derived epigallocatechin gallate (EGCG) to impact the processes that govern the acquisition of spheroids CSC stemness traits. Methods: Neurospheres were generated from adherent human U87 glioblastoma cancer cell cultures under conditions that recapitulate stemness features. Total RNA and protein lysates were isolated for gene expression by RT-qPCR and protein expression by immunoblot. Transcriptomic analysis was performed through RNA-Seq. Results: Compared to their parental adherent cells, tumorspheres expressed increased levels of the CSC markers NANOG, SOX2, PROM1 (CD133), as well as of the epithelial-to-mesenchymal transition (EMT) markers Fibronectin, SNAI1, and 37/67 kDa laminin-1 receptor ribosomal protein SA (RPSA). Increased PROM1, SOX2, Fibronectin, and RPSA transcripts level were also observed in clinical grade IV glioblastoma tissues compared to normal tissue. EGCG treatment reduced dose-dependently tumorspheres size and inhibited the transcriptional regulation of those genes. An apoptotic signature was also found in spheroids with increased signal transducing events involving GSK3α/β, RSK, and CREB. These were repressed upon RPSA gene silencing and partially by SNAI1 silencing. Conclusion: This work highlights a signaling axis linking RPSA upstream of SNAIL in neurospheres genesis and supports the chemopreventive impact that diet-derived EGCG may exert on the acquisition of CSC traits.