Tumor Microenvironment: A New Treatment Target for Cancer

Recent advances in cancer therapy encounter a bottleneck. Relapsing/recurrent disease almost always developed eventually with resistance to the initially effective drugs. Tumor microenvironment has been gradually recognized as a key contributor for cancer progression, epithelial-mesenchymal transition of the cancer cells, angiogenesis, cancer metastasis, and development of drug resistance, while dysregulated immune responses and interactions between various components in the microenvironment all play important roles. Future development of anticancer treatment should take tumor microenvironment into consideration. Besides, we also discuss the limitations of current pre-clinical testing models that mainly come from the impossibility in simulating all detailed carcinogenic mechanisms in human, especially failure to create the same tumor microenvironment. With the cumulating knowledge about tumor microenvironment, the design of a novel anticancer therapy may be facilitated and may have better chance for success in cancer eradication.

Download Full-text

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

Cells ◽

10.3390/cells10030558 ◽

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.

Download Full-text

Galectin-3: A factotum in carcinogenesis bestowing an archery for prevention

Tumor Biology ◽

10.3233/tub-200051 ◽

2021 ◽

Vol 43 (1) ◽

pp. 77-96

Author(s):

T. Jeethy Ram ◽

Asha Lekshmi ◽

Thara Somanathan ◽

K. Sujathan

Keyword(s):

Cancer Progression ◽

Molecular Mechanisms ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Therapy Resistance ◽

Cellular Level ◽

Clinical Samples ◽

Innovative Strategy ◽

Mesenchymal Transition ◽

Galectin 3

Cancer metastasis and therapy resistance are the foremost hurdles in oncology at the moment. This review aims to pinpoint the functional aspects of a unique multifaceted glycosylated molecule in both intracellular and extracellular compartments of a cell namely galectin-3 along with its metastatic potential in different types of cancer. All materials reviewed here were collected through the search engines PubMed, Scopus, and Google scholar. Among the 15 galectins identified, the chimeric gal-3 plays an indispensable role in the differentiation, transformation, and multi-step process of tumor metastasis. It has been implicated in the molecular mechanisms that allow the cancer cells to survive in the intravascular milieu and promote tumor cell extravasation, ultimately leading to metastasis. Gal-3 has also been found to have a pivotal role in immune surveillance and pro-angiogenesis and several studies have pointed out the importance of gal-3 in establishing a resistant phenotype, particularly through the epithelial-mesenchymal transition process. Additionally, some recent findings suggest the use of gal-3 inhibitors in overcoming therapeutic resistance. All these reports suggest that the deregulation of these specific lectins at the cellular level could inhibit cancer progression and metastasis. A more systematic study of glycosylation in clinical samples along with the development of selective gal-3 antagonists inhibiting the activity of these molecules at the cellular level offers an innovative strategy for primary cancer prevention.

Download Full-text

Cooperation of Cancer Stem Cell Properties and Epithelial-Mesenchymal Transition in the Establishment of Breast Cancer Metastasis

Journal of Oncology ◽

10.1155/2011/591427 ◽

2011 ◽

Vol 2011 ◽

pp. 1-7 ◽

Cited By ~ 30

Author(s):

Tetsu Hayashida ◽

Hiromitsu Jinno ◽

Yuko Kitagawa ◽

Masaki Kitajima

Keyword(s):

Breast Cancer ◽

Stem Cell ◽

Cancer Stem Cell ◽

Cancer Progression ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Metastatic Tumor ◽

Breast Cancer Metastasis ◽

Cell Junctions ◽

Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) is a multistep process in which cells acquire molecular alterations such as loss of cell-cell junctions and restructuring of the cytoskeleton. There is an increasing understanding that this process may promote breast cancer progression through promotion of invasive and metastatic tumor growth. Recent observations imply that there may be a cross-talk between EMT and cancer stem cell properties, leading to enhanced tumorigenicity and the capacity to generate heterogeneous tumor cell populations. Here, we review the experimental and clinical evidence for the involvement of EMT in cancer stem cell theory, focusing on the common characteristics of this phenomenon.

Download Full-text

Breast Cancer Metastasis: Role of Tumor Microenvironment and Resident Macropahges

Defence Life Science Journal ◽

10.14429/dlsj.1.10058 ◽

2016 ◽

Vol 1 (1) ◽

pp. 48

Author(s):

Khemraj Singh Baghel ◽

Smrati Bhadauria

Keyword(s):

Breast Cancer ◽

Tumor Microenvironment ◽

Cancer Cells ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Metastatic Breast ◽

Breast Cancer Metastasis ◽

The Body ◽

Tissue Remodelling ◽

Mesenchymal Transition

Metastatic breast cancer is a stage of breast cancer wherever the disease has spread to distant parts of the body. Onset of metastasis is one of the biggest obstacles to the successful treatment of cancer. The potential of a tumor cell to metastasize profoundly depends on its microenvironment, or “niche” interactions with local components. Macrophages provide tropic support to tumors. Resident macrophages contribute a set of common functions, including their capability to defend against microbial infections, to maintain normal cell turnover and tissue remodelling, and to help repair sites of injury. Macrophages are recruited into the tumor microenvironment where they differentiate to become Tumor-associated-macrophages (TAMs). TAMs are the most abundant subpopulation of tumor-stroma and actively drive cancer cell invasion and metastasis. Cancer metastasis is not solely regulated by the deregulation of metastasis promoting or suppressing genes in cancer cells. Recently the interaction between the stromal cells and cancer cells has been demonstrated to promote cancer metastasis. TAMs can advocate epithelial-mesenchymal transition of cancer cells. Loss of e-cadherin, a major phenomenon of epithelial to mesenchymal transition (EMT), reduces adhesiveness and releases cancer cells to distant (secondary) sites. A positive correlation between tumor progression and the expression of matrix metallo proteinases (MMPs) in tumor tissues has been demonstrated in numerous human and animal studies. The dynamic interactions of cancer-cells with TAMs actively promote invasion-metastasis cascade through intercellular-signalling-networks that need better elucidation.

Download Full-text

Orai3 Regulates Pancreatic Cancer Metastasis by Encoding a Functional Store Operated Calcium Entry Channel

10.20944/preprints202110.0400.v1 ◽

2021 ◽

Author(s):

Samriddhi Arora ◽

Jyoti Tanwar ◽

Nutan Sharma ◽

Suman Saurav ◽

Rajender K. Motiani

Keyword(s):

Pancreatic Cancer ◽

Survival Time ◽

Cell Lines ◽

Cancer Progression ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Critical Role ◽

Mesenchymal Transition

Pancreatic cancer (PC) is one of the most lethal forms of cancers with 5-year mean survival rate of less than 10%. Most of the PC associated deaths are due to metastasis to secondary sites. Calcium (Ca2+) signaling plays a critical role in regulating hallmarks of cancer progression including cell proliferation, migration and apoptotic resistance. Store operated Ca2+ entry (SOCE) mediated by Orai1/2/3 channels is a highly regulated and ubiquitous pathway responsible for Ca2+ influx into non-excitable cells. In this study, we performed extensive bioinformatic analysis of publicly available datasets and observed that Orai3 expression is inversely associated with the mean survival time of PC patients. Orai3 expression analysis in a battery of PC cell lines corroborated its differential expression profile. We then carried out thorough Ca2+ imaging experiments in 6 PC cell lines and found that Orai3 forms a functional SOCE in PC cells. Our in vitro functional assays show that Orai3 regulates PC cell cycle progression, apoptosis and migration. Most importantly, our in vivo xenograft studies demonstrate a critical role of Orai3 in PC tumor growth and secondary metastasis. Mechanistically, Orai3 controls G1 phase progression, matrix metalloproteinase expression and epithelial-mesenchymal transition in PC cells. Taken together, this study for the first time reports that Orai3 drives aggressive phenotypes of PC cells i.e. migration in vitro and metastasis in vivo. Considering that Orai3 expression is inversely associated with the PC patients survival time, it appears to be a highly attractive therapeutic target.

Download Full-text

Emerging Autophagy Functions Shape the Tumor Microenvironment and Play a Role in Cancer Progression - Implications for Cancer Therapy

Frontiers in Oncology ◽

10.3389/fonc.2020.606436 ◽

2020 ◽

Vol 10 ◽

Author(s):

Silvina Odete Bustos ◽

Fernanda Antunes ◽

Maria Cristina Rangel ◽

Roger Chammas

Keyword(s):

Tumor Microenvironment ◽

Cancer Therapy ◽

Cancer Cells ◽

Cancer Progression ◽

Stress Responses ◽

Epithelial Mesenchymal Transition ◽

Metastatic Potential ◽

Secretory Proteins ◽

Mesenchymal Transition ◽

Independent Functions

The tumor microenvironment (TME) is a complex environment where cancer cells reside and interact with different types of cells, secreted factors, and the extracellular matrix. Additionally, TME is shaped by several processes, such as autophagy. Autophagy has emerged as a conserved intracellular degradation pathway for clearance of damaged organelles or aberrant proteins. With its central role, autophagy maintains the cellular homeostasis and orchestrates stress responses, playing opposite roles in tumorigenesis. During tumor development, autophagy also mediates autophagy-independent functions associated with several hallmarks of cancer, and therefore exerting several effects on tumor suppression and/or tumor promotion mechanisms. Beyond the concept of degradation, new different forms of autophagy have been described as modulators of cancer progression, such as secretory autophagy enabling intercellular communication in the TME by cargo release. In this context, the synthesis of senescence-associated secretory proteins by autophagy lead to a senescent phenotype. Besides disturbing tumor treatment responses, autophagy also participates in innate and adaptive immune signaling. Furthermore, recent studies have indicated intricate crosstalk between autophagy and the epithelial-mesenchymal transition (EMT), by which cancer cells obtain an invasive phenotype and metastatic potential. Thus, autophagy in the cancer context is far broader and complex than just a cell energy sensing mechanism. In this scenario, we will discuss the key roles of autophagy in the TME and surrounding cells, contributing to cancer development and progression/EMT. Finally, the potential intervention in autophagy processes as a strategy for cancer therapy will be addressed.

Download Full-text

Hybrid Epithelial/Mesenchymal State in Cancer Metastasis: Clinical Significance and Regulatory Mechanisms

Cells ◽

10.3390/cells9030623 ◽

2020 ◽

Vol 9 (3) ◽

pp. 623 ◽

Cited By ~ 13

Author(s):

Tsai-Tsen Liao ◽

Muh-Hwa Yang

Keyword(s):

Cancer Cells ◽

Cancer Progression ◽

Normal Tissue ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Regulatory Mechanisms ◽

Dynamic Changes ◽

Mesenchymal Transition ◽

Stressful Environment ◽

Metastatic Process

Epithelial-mesenchymal transition (EMT) has been well recognized for its essential role in cancer progression as well as normal tissue development. In cancer cells, activation of EMT permits the cells to acquire migratory and invasive abilities and stem-like properties. However, simple categorization of cancer cells into epithelial and mesenchymal phenotypes misleads the understanding of the complicated metastatic process, and contradictory results from different studies also indicate the limitation of application of EMT theory in cancer metastasis. Nowadays, growing evidence suggests the existence of an intermediate status between epithelial and mesenchymal phenotypes, i.e., the “hybrid epithelial-mesenchymal (hybrid E/M)” state, provides a possible explanation for those conflicting results. Appearance of hybrid E/M phenotype offers a more plastic status for cancer cells to adapt the stressful environment for proceeding metastasis. In this article, we review the biological importance of the dynamic changes between the epithelial and the mesenchymal states. The regulatory mechanisms encompassing the translational, post-translational, and epigenetic control for this complex and plastic status are also discussed.

Download Full-text

Gelsolin Promotes Cancer Progression by Regulating Epithelial-Mesenchymal Transition in Hepatocellular Carcinoma and Correlates with a Poor Prognosis

Journal of Oncology ◽

10.1155/2020/1980368 ◽

2020 ◽

Vol 2020 ◽

pp. 1-10 ◽

Cited By ~ 1

Author(s):

Yixi Zhang ◽

Xiaojing Luo ◽

Jianwei Lin ◽

Shunjun Fu ◽

Pei Feng ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Cancer Progression ◽

Poor Prognosis ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Disease Free Survival ◽

Tumour Cells ◽

Migration And Invasion ◽

Mesenchymal Transition

Gelsolin (GSN), a cytoskeletal protein, is frequently overexpressed in different cancers and promotes cell motility. The biological function of GSN in hepatocellular carcinoma (HCC) and its mechanism remain unclear. The expression of GSN was assessed in a cohort of 188 HCC patients. The effects of GSN on the migration and invasion of tumour cells were examined. Then, the role of GSN in tumour growth in vivo was determined by using a cancer metastasis assay. The possible mechanism by which GSN promotes HCC progression was explored. As a result, GSN was overexpressed in HCC tissues. High GSN expression was significantly correlated with late Edmondson grade, encapsulation, and multiple tumours. Patients with high GSN expression had worse overall survival (OS) and disease-free survival (DFS) than those with low GSN expression. GSN expression was identified as an independent risk factor in both OS (hazard risk (HR) = 1.620, 95% confidence interval (CI) = 1.105–2.373, P<0.001) and DFS (HR = 1.744, 95% CI = 1.205–2.523, P=0.003). Moreover, GSN knockdown significantly inhibited the migration and invasion of HCC tumour cells, while GSN overexpression attenuated these effects by regulating epithelial-mesenchymal transition (EMT) In conclusion, GSN promotes cancer progression and is associated with a poor prognosis in HCC patients. GSN promotes HCC progression by regulating EMT.

Download Full-text

Dynamics of Phenotypic Heterogeneity Associated with EMT and Stemness during Cancer Progression

Journal of Clinical Medicine ◽

10.3390/jcm8101542 ◽

2019 ◽

Vol 8 (10) ◽

pp. 1542 ◽

Cited By ~ 36

Author(s):

Mohit Kumar Jolly ◽

Toni Celià-Terrassa

Keyword(s):

Cancer Progression ◽

Molecular Mechanisms ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Relevant Literature ◽

Phenotypic Heterogeneity ◽

State Transitions ◽

Strong Impact ◽

Mesenchymal Transition ◽

Cancer Aggressiveness

Genetic and phenotypic heterogeneity contribute to the generation of diverse tumor cell populations, thus enhancing cancer aggressiveness and therapy resistance. Compared to genetic heterogeneity, a consequence of mutational events, phenotypic heterogeneity arises from dynamic, reversible cell state transitions in response to varying intracellular/extracellular signals. Such phenotypic plasticity enables rapid adaptive responses to various stressful conditions and can have a strong impact on cancer progression. Herein, we have reviewed relevant literature on mechanisms associated with dynamic phenotypic changes and cellular plasticity, such as epithelial–mesenchymal transition (EMT) and cancer stemness, which have been reported to facilitate cancer metastasis. We also discuss how non-cell-autonomous mechanisms such as cell–cell communication can lead to an emergent population-level response in tumors. The molecular mechanisms underlying the complexity of tumor systems are crucial for comprehending cancer progression, and may provide new avenues for designing therapeutic strategies.

Download Full-text

Toward understanding cancer stem cell heterogeneity in the tumor microenvironment

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1815345116 ◽

2018 ◽

Vol 116 (1) ◽

pp. 148-157 ◽

Cited By ~ 73

Author(s):

Federico Bocci ◽

Larisa Gearhart-Serna ◽

Marcelo Boareto ◽

Mariana Ribeiro ◽

Eshel Ben-Jacob ◽

...

Keyword(s):

Stem Cell ◽

Tumor Microenvironment ◽

Cancer Stem Cell ◽

Tumor Progression ◽

Cancer Metastasis ◽

Epithelial Mesenchymal Transition ◽

Spatiotemporal Dynamics ◽

Spatial Proximity ◽

Mesenchymal Transition

The epithelial–mesenchymal transition (EMT) and cancer stem cell (CSC) formation are two paramount processes driving tumor progression, therapy resistance, and cancer metastasis. Recent experiments show that cells with varying EMT and CSC phenotypes are spatially segregated in the primary tumor. The underlying mechanisms generating such spatiotemporal dynamics in the tumor microenvironment, however, remain largely unexplored. Here, we show through a mechanism-based dynamical model that the diffusion of EMT-inducing signals such as TGF-β, together with noncell autonomous control of EMT and CSC decision making via the Notch signaling pathway, can explain experimentally observed disparate localization of subsets of CSCs with varying EMT phenotypes in the tumor. Our simulations show that the more mesenchymal CSCs lie at the invasive edge, while the hybrid epithelial/mesenchymal (E/M) CSCs reside in the tumor interior. Further, motivated by the role of Notch-Jagged signaling in mediating EMT and stemness, we investigated the microenvironmental factors that promote Notch-Jagged signaling. We show that many inflammatory cytokines such as IL-6 that can promote Notch-Jagged signaling can (i) stabilize a hybrid E/M phenotype, (ii) increase the likelihood of spatial proximity of hybrid E/M cells, and (iii) expand the fraction of CSCs. To validate the predicted connection between Notch-Jagged signaling and stemness, we knocked down JAG1 in hybrid E/M SUM149 human breast cancer cells in vitro. JAG1 knockdown significantly restricted tumor organoid formation, confirming the key role that Notch-Jagged signaling can play in tumor progression. Together, our integrated computational–experimental framework reveals the underlying principles of spatiotemporal dynamics of EMT and CSCs.

Download Full-text