scholarly journals The Role of Tumor Microenvironment in Cancer Metastasis: Molecular Mechanisms and Therapeutic Opportunities

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2053
Author(s):  
Christiana M. Neophytou ◽  
Myrofora Panagi ◽  
Triantafyllos Stylianopoulos ◽  
Panagiotis Papageorgis
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Hypoxic Conditions ◽  
Surrounding Matrix ◽  
Tumor Survival ◽  
Metastatic Process ◽  
Growth Promoting

The tumor microenvironment (TME) regulates essential tumor survival and promotion functions. Interactions between the cellular and structural components of the TME allow cancer cells to become invasive and disseminate from the primary site to distant locations, through a complex and multistep metastatic cascade. Tumor-associated M2-type macrophages have growth-promoting and immunosuppressive functions; mesenchymal cells mass produce exosomes that increase the migratory ability of cancer cells; cancer associated fibroblasts (CAFs) reorganize the surrounding matrix creating migration-guiding tracks for cancer cells. In addition, the tumor extracellular matrix (ECM) exerts determinant roles in disease progression and cancer cell migration and regulates therapeutic responses. The hypoxic conditions generated at the primary tumor force cancer cells to genetically and/or epigenetically adapt in order to survive and metastasize. In the circulation, cancer cells encounter platelets, immune cells, and cytokines in the blood microenvironment that facilitate their survival and transit. This review discusses the roles of different cellular and structural tumor components in regulating the metastatic process, targeting approaches using small molecule inhibitors, nanoparticles, manipulated exosomes, and miRNAs to inhibit tumor invasion as well as current and future strategies to remodel the TME and enhance treatment efficacy to block the detrimental process of metastasis.

scholarly journals Role of acidic tumor microenvironment in tumor pathogenesis and targeting

2020 ◽  
pp. 34-40
Author(s):  
Vishal Sharma ◽  
Chhaya Bawa ◽  
Kuldeep Chand Vatsyan
Keyword(s):  
Cell Growth ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Physiological State ◽  
Therapeutic Interventions ◽  
Cancer Cell Growth ◽  
Molecular Alterations ◽  
Cancer Pathogenesis

Extensive efforts are going on to understand the molecular mechanisms behind tumor initiation, progression, and invasion and find novel targets for cancer treatment. The physiological state of the tumor microenvironment (TME) is crucial to every step of tumor cell growth and angiogenesis. Cancer cells are rarely in contact with each other. The intervening medium between the cancer cells, immune cells, and other cells become acidic, which significantly affects cancer pathogenesis. It could be a novel targeting marker and may help treat tumors. Even after extensive research in this area, the nature of molecular alterations and the basic mechanisms in the tumor microenvironment remains unclear. Based on recent studies of TME, this mini-review bids a more inclusive overview of the role of TME in cancer cell growth. Also, it helps to understand the potential of TME for therapeutic interventions.

scholarly journals Role of Estrogen Receptor Signaling in Breast Cancer Metastasis

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Sudipa Saha Roy ◽  
Ratna K. Vadlamudi
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Breast Cancer Cells ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Metastatic Breast ◽  
Estrogen Signaling

Metastatic breast cancer is a life-threatening stage of cancer and is the leading cause of death in advanced breast cancer patients. Estrogen signaling and the estrogen receptor (ER) are implicated in breast cancer progression, and the majority of the human breast cancers start out as estrogen dependent. Accumulating evidence suggests that ER signaling is complex, involving coregulatory proteins and extranuclear actions. ER-coregualtory proteins are tightly regulated under normal conditions with miss expression primarily reported in cancer. Deregulation of ER coregualtors or ER extranuclear signaling has potential to promote metastasis in ER-positive breast cancer cells. This review summarizes the emerging role of ER signaling in promoting metastasis of breast cancer cells, discusses the molecular mechanisms by which ER signaling contributes to metastasis, and explores possible therapeutic targets to block ER-driven metastasis.

scholarly journals The Role of Platelets in the Tumor-Microenvironment and the Drug Resistance of Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 240 ◽  
Author(s):  
Phung Huong ◽  
Lap Nguyen ◽  
Xuan-Bac Nguyen ◽  
Sang Lee ◽  
Duc-Hiep Bach
Keyword(s):  
Drug Resistance ◽  
Growth Factors ◽  
Tumor Microenvironment ◽  
Treatment Failure ◽  
Cancer Treatment ◽  
Cancer Cells ◽  
Cancer Metastasis ◽  
Chemotherapeutic Drugs ◽  
Activated Platelets

Besides the critical functions in hemostasis, thrombosis and the wounding process, platelets have been increasingly identified as active players in various processes in tumorigenesis, including angiogenesis and metastasis. Once activated, platelets can release bioactive contents such as lipids, microRNAs, and growth factors into the bloodstream, subsequently enhancing the platelet–cancer interaction and stimulating cancer metastasis and angiogenesis. The mechanisms of treatment failure of chemotherapeutic drugs have been investigated to be associated with platelets. Therefore, understanding how platelets contribute to the tumor microenvironment may potentially identify strategies to suppress cancer angiogenesis, metastasis, and drug resistance. Herein, we present a review of recent investigations on the role of platelets in the tumor-microenvironment including angiogenesis, and metastasis, as well as targeting platelets for cancer treatment, especially in drug resistance.

The Role of Cytokines in Interactions of Mesenchymal Stem Cells and Breast Cancer Cells

2020 ◽  
Vol 15 ◽  
Author(s):  
Hariharan Jayaraman ◽  
Nalinkanth V. Ghone ◽  
Ranjith Kumaran R ◽  
Himanshu Dashora
Keyword(s):  
Breast Cancer ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Cell Communication ◽  
Extra Cellular Matrix ◽  
Cytokine Signaling ◽  
Cellular Matrix

: Mesenchymal stem cells because of its high proliferation, differentiation, regenerative capacity, and ease of availability have been a popular choice in cytotherapy. Mesenchymal Stem Cells (MSCs) have a natural tendency to home in a tumor microenvironment and acts against it, owing to the similarity of the latter to an injured tissue environment. Several studies have confirmed the recruitment of MSCs by tumor through various cytokine signaling that brings about phenotypic changes to cancer cells, thereby promoting migration, invasion, and adhesion of cancer cells. The contrasting results on MSCs as a tool for cancer cytotherapy may be due to the complex cell to cell interaction in the tumor microenvironment, which involves various cell types such as cancer cells, immune cells, endothelial cells, and cancer stem cells. Cell to cell communication can be simple or complex and it is transmitted through various cytokines among multiple cell phenotypes, mechano-elasticity of the extra-cellular matrix surrounding the cancer cells, and hypoxic environments. In this article, the role of the extra-cellular matrix proteins and soluble mediators that acts as communicators between mesenchymal stem cells and cancer cells has been reviewed specifically for breast cancer, as it is the leading member of cancer malignancies. The comprehensive information may be beneficial in finding a new combinatorial cytotherapeutic strategy using MSCs by exploiting the cross-talk between mesenchymal stem cells and cancer cells for treating breast cancer.

scholarly journals Oxidized Phospholipids in Tumor Microenvironment Stimulate Tumor Metastasis via Regulation of Autophagy

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 558
Author(s):  
Jin Kyung Seok ◽  
Eun-Hee Hong ◽  
Gabsik Yang ◽  
Hye Eun Lee ◽  
Sin-Eun Kim ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Cancer Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Migration And Invasion ◽  
Autophagic Flux ◽  
Oxidized Phospholipids ◽  
Mcf7 Cells ◽  
Mesenchymal Transition ◽  
Tumor Tissues

Oxidized phospholipids are well known to play physiological and pathological roles in regulating cellular homeostasis and disease progression. However, their role in cancer metastasis has not been entirely understood. In this study, effects of oxidized phosphatidylcholines such as 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) on epithelial-mesenchymal transition (EMT) and autophagy were determined in cancer cells by immunoblotting and confocal analysis. Metastasis was analyzed by a scratch wound assay and a transwell migration/invasion assay. The concentrations of POVPC and 1-palmitoyl-2-glutaroyl-sn-glycero-phosphocholine (PGPC) in tumor tissues obtained from patients were measured by LC-MS/MS analysis. POVPC induced EMT, resulting in increase of migration and invasion of human hepatocellular carcinoma cells (HepG2) and human breast cancer cells (MCF7). POVPC induced autophagic flux through AMPK-mTOR pathway. Pharmacological inhibition or siRNA knockdown of autophagy decreased migration and invasion of POVPC-treated HepG2 and MCF7 cells. POVPC and PGPC levels were greatly increased at stage II of patient-derived intrahepatic cholangiocarcinoma tissues. PGPC levels were higher in malignant breast tumor tissues than in adjacent nontumor tissues. The results show that oxidized phosphatidylcholines increase metastatic potential of cancer cells by promoting EMT, mediated through autophagy. These suggest the positive regulatory role of oxidized phospholipids accumulated in tumor microenvironment in the regulation of tumorigenesis and metastasis.

scholarly journals Metabolome Shift in Both Metastatic Breast Cancer Cells and Astrocytes Which May Contribute to the Tumor Microenvironment

2021 ◽  
Vol 22 (14) ◽  
pp. 7430
Author(s):  
Hiromi Sato ◽  
Ayaka Shimizu ◽  
Toya Okawa ◽  
Miaki Uzu ◽  
Momoko Goto ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Metastatic Breast ◽  
Principal Component ◽  
Pentose Phosphate ◽  
Metastatic Brain Tumors ◽  
Pentose Phosphate Pathways ◽  
Culture Supernatants

The role of astrocytes in the periphery of metastatic brain tumors is unclear. Since astrocytes regulate central nervous metabolism, we hypothesized that changes in astrocytes induced by contact with cancer cells would appear in the metabolome of both cells and contribute to malignant transformation. Coculture of astrocytes with breast cancer cell supernatants altered glutamate (Glu)-centered arginine–proline metabolism. Similarly, the metabolome of cancer cells was also altered by astrocyte culture supernatants, and the changes were further amplified in astrocytes exposed to Glu. Inhibition of Glu uptake in astrocytes reduces the variability in cancer cells. Principal component analysis of the cancer cells revealed that all these changes were in the first principal component (PC1) axis, where the responsible metabolites were involved in the metabolism of the arginine–proline, pyrimidine, and pentose phosphate pathways. The contribution of these changes to the tumor microenvironment needs to be further pursued.

scholarly journals Hypoxic tumor microenvironment: Implications for cancer therapy

2020 ◽  
Vol 245 (13) ◽  
pp. 1073-1086
Author(s):  
Sukanya Roy ◽  
Subhashree Kumaravel ◽  
Ankith Sharma ◽  
Camille L Duran ◽  
Kayla J Bayless ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Cancer Cells ◽  
Metabolic Regulation ◽  
Molecular Mechanisms ◽  
Hypoxia Inducible Factor ◽  
Tumor Vasculature ◽  
Therapeutic Strategies ◽  
Therapeutic Resistance ◽  
Low Oxygen ◽  
Cancer Types

Hypoxia or low oxygen concentration in tumor microenvironment has widespread effects ranging from altered angiogenesis and lymphangiogenesis, tumor metabolism, growth, and therapeutic resistance in different cancer types. A large number of these effects are mediated by the transcription factor hypoxia inducible factor 1⍺ (HIF-1⍺) which is activated by hypoxia. HIF1⍺ induces glycolytic genes and reduces mitochondrial respiration rate in hypoxic tumoral regions through modulation of various cells in tumor microenvironment like cancer-associated fibroblasts. Immune evasion driven by HIF-1⍺ further contributes to enhanced survival of cancer cells. By altering drug target expression, metabolic regulation, and oxygen consumption, hypoxia leads to enhanced growth and survival of cancer cells. Tumor cells in hypoxic conditions thus attain aggressive phenotypes and become resistant to chemo- and radio- therapies resulting in higher mortality. While a number of new therapeutic strategies have succeeded in targeting hypoxia, a significant improvement of these needs a more detailed understanding of the various effects and molecular mechanisms regulated by hypoxia and its effects on modulation of the tumor vasculature. This review focuses on the chief hypoxia-driven molecular mechanisms and their impact on therapeutic resistance in tumors that drive an aggressive phenotype. Impact statement Hypoxia contributes to tumor aggressiveness and promotes growth of many solid tumors that are often resistant to conventional therapies. In order to achieve successful therapeutic strategies targeting different cancer types, it is necessary to understand the molecular mechanisms and signaling pathways that are induced by hypoxia. Aberrant tumor vasculature and alterations in cellular metabolism and drug resistance due to hypoxia further confound this problem. This review focuses on the implications of hypoxia in an inflammatory TME and its impact on the signaling and metabolic pathways regulating growth and progression of cancer, along with changes in lymphangiogenic and angiogenic mechanisms. Finally, the overarching role of hypoxia in mediating therapeutic resistance in cancers is discussed.

scholarly journals Microenvironment-mediated cancer dormancy: Insights from metastability theory

2021 ◽  
Vol 119 (1) ◽  
pp. e2111046118
Author(s):  
Sadra Bakhshandeh ◽  
Carsten Werner ◽  
Peter Fratzl ◽  
Amaia Cipitria
Keyword(s):  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Droplet Growth ◽  
Protective Mechanism ◽  
Dormant State ◽  
Strong Focus ◽  
Tumor Tissues ◽  
Cancer Dormancy ◽  
Thermodynamic Phase

Dormancy is an evolutionarily conserved protective mechanism widely observed in nature. A pathological example is found during cancer metastasis, where cancer cells disseminate from the primary tumor, home to secondary organs, and enter a growth-arrested state, which could last for decades. Recent studies have pointed toward the microenvironment being heavily involved in inducing, preserving, or ceasing this dormant state, with a strong focus on identifying specific molecular mechanisms and signaling pathways. Increasing evidence now suggests the existence of an interplay between intracellular as well as extracellular biochemical and mechanical cues in guiding such processes. Despite the inherent complexities associated with dormancy, proliferation, and growth of cancer cells and tumor tissues, viewing these phenomena from a physical perspective allows for a more global description, independent from many details of the systems. Building on the analogies between tissues and fluids and thermodynamic phase separation concepts, we classify a number of proposed mechanisms in terms of a thermodynamic metastability of the tumor with respect to growth. This can be governed by interaction with the microenvironment in the form of adherence (wetting) to a substrate or by mechanical confinement of the surrounding extracellular matrix. By drawing parallels with clinical and experimental data, we advance the notion that the local energy minima, or metastable states, emerging in the tissue droplet growth kinetics can be associated with a dormant state. Despite its simplicity, the provided framework captures several aspects associated with cancer dormancy and tumor growth.

scholarly journals SPNS2 Downregulation Induces EMT and Promotes Colorectal Cancer Metastasis via Activating AKT Signaling Pathway

2021 ◽  
Vol 11 ◽  
Author(s):  
Lei Lv ◽  
Qiyi Yi ◽  
Ying Yan ◽  
Fengmei Chao ◽  
Ming Li
Keyword(s):  
Colorectal Cancer ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Ectopic Expression ◽  
Migration And Invasion ◽  
Akt Inhibitor ◽  
Colon Adenoma ◽  
Mesenchymal Transition

Spinster homologue 2 (SPNS2), a transporter of S1P (sphingosine-1-phosphate), has been reported to mediate immune response, vascular development, and pathologic processes of diseases such as cancer via S1P signaling pathways. However, its biological functions and expression profile in colorectal cancer (CRC) is elusive. In this study, we disclosed that SPNS2 expression, which was regulated by copy number variation and DNA methylation of its promoter, was dramatically upregulated in colon adenoma and CRC compared to normal tissues. However, its expression was lower in CRC than in colon adenoma, and low expression of SPN2 correlated with advanced T/M/N stage and poor prognosis in CRC. Ectopic expression of SPNS2 inhibited cell proliferation, migration, epithelial–mesenchymal transition (EMT), invasion, and metastasis in CRC cell lines, while silencing SPNS2 had the opposite effects. Meanwhile, measuring the intracellular and extracellular level of S1P after overexpression of SPNS2 pinpointed a S1P-independent model of SPNS2. Mechanically, SPNS2 led to PTEN upregulation and inactivation of Akt. Moreover, AKT inhibitor (MK2206) abrogated SPNS2 knockdown-induced promoting effects on the migration and invasion, while AKT activator (SC79) reversed the repression of migration and invasion by SPNS2 overexpression in CRC cells, confirming the pivotal role of AKT for SPNS2’s function. Collectively, our study demonstrated the suppressor role of SPNS2 during CRC metastasis, providing new insights into the pathology and molecular mechanisms of CRC progression.

scholarly journals miR-200 deficiency promotes lung cancer metastasis by activating cancer-associated fibroblasts

2020 ◽  
Author(s):  
Bin Xue ◽  
Chen-Hua Chuang ◽  
Haydn M. Prosser ◽  
Cesar Seigi Fuziwara ◽  
Claudia Chan ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Lung Adenocarcinoma ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Cancer Metastasis ◽  
Lung Cancer Mortality ◽  
Tumor Stroma ◽  
Metastatic Potential ◽  
Human Lung Cancer ◽  
Cancer Associated Fibroblasts

AbstractLung adenocarcinoma, the most prevalent lung cancer subtype, is characterized by its high propensity to metastasize. Despite the importance of metastasis in lung cancer mortality, its underlying cellular and molecular mechanisms remain largely elusive. Here, we identified miR-200 miRNAs as potent suppressors for lung adenocarcinoma metastasis. miR-200 expression is specifically repressed in mouse metastatic lung adenocarcinomas, and miR-200 decrease strongly correlates with poor patient survival. Consistently, deletion of mir-200c/141 in the KrasLSL-G12D/+; Trp53flox/flox lung adenocarcinoma mouse model significantly promoted metastasis, generating a desmoplastic tumor stroma highly reminiscent of metastatic human lung cancer. miR-200 deficiency in lung cancer cells promotes the proliferation and activation of adjacent cancer-associated fibroblasts (CAFs), which in turn elevates the metastatic potential of cancer cells. miR-200 regulates the functional interaction between cancer cells and CAFs, at least in part, by targeting Notch ligand Jagged1 and Jagged2 in cancer cells and inducing Notch activation in adjacent CAFs. Hence, the interaction between cancer cells and CAFs constitutes an essential mechanism to promote metastatic potential.

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