Soft fibrin matrix downregulates DAB2IP to promote Nanog-dependent growth of colon tumor-repopulating cells

An update on the tumor-suppressive functions of the RasGAP protein DAB2IP with focus on therapeutic implications

The dynamic crosstalk between tumor and stromal cells is a major determinant of cancer aggressiveness. The tumor-suppressor DAB2IP (Disabled homolog 2 interacting protein) plays an important role in this context, since it modulates cell responses to multiple extracellular inputs, including inflammatory cytokines and growth factors. DAB2IP is a RasGAP and negatively controls Ras-dependent mitogenic signals. In addition, it modulates other major oncogenic pathways, including TNFα/NF-κB, WNT/β-catenin, PI3K/AKT, and androgen receptor signaling. In line with its tumor-suppressive role, DAB2IP is frequently inactivated in cancer by transcriptional and post-transcriptional mechanisms, including promoter methylation, microRNA-mediated downregulation, and protein-protein interactions. Intriguingly, some observations suggest that downregulation of DAB2IP in cells of the tumor stroma could foster establishment of a pro-metastatic microenvironment. This review summarizes recent insights into the tumor-suppressive functions of DAB2IP and the consequences of its inactivation in cancer. In particular, we explore potential approaches aimed at reactivating DAB2IP, or augmenting its expression levels, as a novel strategy in cancer treatment. We suggest that reactivation or upregulation of DAB2IP would concurrently attenuate multiple oncogenic pathways in both cancer cells and the tumor microenvironment, with implications for improved treatment of a broad spectrum of tumors.

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.

Exploring the interaction between extracellular matrix components in a 3D organoid disease model to replicate the pathophysiology of breast cancer

In vitro models are necessary to study the pathophysiology of the disease and the development of effective, tailored treatment methods owing to the complexity and heterogeneity of breast cancer and the large population affected by it. The cellular connections and tumor microenvironments observed in vivo are often not recapitulated in conventional two-dimensional (2D) cell cultures. Therefore, developing 3D in vitro models that mimic the complex architecture and physiological circumstances of breast tumors is crucial for advancing our understanding of the illness. A 3D scaffold-free in vitro disease model mimics breast cancer pathophysiology by allowing cells to self-assemble/pattern into 3D structures, in contrast with other 3D models that rely on artificial scaffolds. It is possible that this model, whether applied to breast tumors using patient-derived primary cells (fibroblasts, endothelial cells, and cancer cells), can accurately replicate the observed heterogeneity. The complicated interactions between different cell types are modelled by integrating critical components of the tumor microenvironment, such as the extracellular matrix, vascular endothelial cells, and tumor growth factors. Tissue interactions, immune cell infiltration, and the effects of the milieu on drug resistance can be studied using this scaffold-free 3D model. The scaffold-free 3D in vitro disease model for mimicking tumor pathophysiology in breast cancer is a useful tool for studying the molecular basis of the disease, identifying new therapeutic targets, and evaluating treatment modalities. It provides a more physiologically appropriate high-throughput platform for screening large compound library in a 96-384 well format. We critically discussed the rapid development of personalized treatment strategies and accelerated drug screening platforms to close the gap between traditional 2D cell culture and in vivo investigations.

Matrix Stiffness Regulated Endoplasmic Reticulum Stress-mediated Apoptosis of Osteosarcoma Cell through Ras Signal Cascades

The modulating effects of matrix stiffness on spreading and apoptosis of tumor cells have been well recognized. Nevertheless, the detail road map leading to the apoptosis and the underlying mechanisms governing the cell apoptosis have remained to be elucidated. To this aim, we provided a tunable elastic hydrogel matrix that promoted cell adhesion by modifying the surface of polyacrylamide with polydopamine, with stiffness value of 1, 10, 30, and 250 kPa, respectively. While the cell spreading increased and the apoptosis decreased with the matrix stiffness, such modulating effect of matrix on cell spreading exhibited different time evolvement behaviors as a function of stiffness, which likely led to surprisingly similar apoptosis rates for the 30 kPa and 250 kPa samples. Matrix stiffness mediated the spreading and apoptosis of MG-63 cells by regulating cell adhesion to matrix and in particular cytoskeletal organization, which was dependent on Ras, Rap1 and PI3K-Akt signaling pathways and finally led to the apoptosis of cancer cells dominated by endoplasmic reticulum stress pathway. Our results provided an insight into the regulation of tumor cell fate by the mechanical clues of ECM, which would have implication for future cancer research and the design of novel anticancer materials.

Extracellular fibrin promotes non-small cell lung cancer progression through integrin β1/PTEN/AKT signaling

The extracellular matrix (ECM) has been strongly correlated with cancer progression in various tumor types. However, the specific mechanisms underlying ECM-associated tumor behaviors remain unclear. In this study, we found an enriched distribution of fibrin in tumor tissues obtained from high-grade non-small cell lung cancer (NSCLC) patients. For further investigation, we established an in vitro 3D culture system using fibrin gel and found that NSCLC cells grown in this system exhibited increased stemness and tumorigenesis. Mechanistically, we demonstrated that fibrin facilitated the activation of the phosphatase and tensin homolog (PTEN)/protein kinase B (AKT) signaling pathway through integrin β1. Furthermore, we found that blocking integrin β1 signals enhanced the tumor suppressive effects of chemotherapy, providing a novel approach for clinical therapy for NSCLC.

Molecular Mechanisms of Tumor Cell Stemness Modulation during Formation of Spheroids

Cancer stem cells (CSCs), their properties and interaction with microenvironment are of interest in modern medicine and biology. There are many studies on the emergence of CSCs and their involvement in tumor pathogenesis. The most important property inherent to CSCs is their stemness. Stemness combines ability of the cell to maintain its pluripotency, give rise to differentiated cells, and interact with environment to maintain a balance between dormancy, proliferation, and regeneration. While adult stem cells exhibit these properties by participating in tissue homeostasis, CSCs behave as their malignant equivalents. High tumor resistance to therapy, ability to differentiate, activate angiogenesis and metastasis arise precisely due to the stemness of CSCs. These cells can be used as a target for therapy of different types of cancer. Laboratory models are needed to study cancer biology and find new therapeutic strategies. A promising direction is three-dimensional tumor models or spheroids. Such models exhibit properties resembling stemness in a natural tumor. By modifying spheroids, it becomes possible to investigate the effect of therapy on CSCs, thus contributing to the development of anti-tumor drug test systems. The review examines the niche of CSCs, the possibility of their study using three-dimensional spheroids, and existing markers for assessing stemness of CSCs.

The Tumor Suppressor DAB2IP Is Regulated by Cell Contact and Contributes to YAP/TAZ Inhibition in Confluent Cells

External and internal mechanical forces modulate cell morphology, movement, proliferation and metabolism, and represent crucial inputs for tissue homeostasis. The transcriptional regulators YAP and TAZ are important effectors of mechanical signaling and are frequently activated in solid tumors, correlating with metastasis, chemoresistance, and shorter patient survival. YAP/TAZ activity is controlled by various pathways that sense cell shape, polarity, contacts, and mechanical tension. In tumors, aberrant YAP/TAZ activation may result from cancer-related alterations of such regulatory networks. The tumor suppressor DAB2IP is a Ras-GAP and scaffold protein that negatively modulates multiple oncogenic pathways and is frequently downregulated or inactivated in solid tumors. Here, we provide evidence that DAB2IP expression is sustained by cell confluency. We also find that DAB2IP depletion in confluent cells alters their morphology, reducing cell packing while increasing cell stiffness. Finally, we find that DAB2IP depletion in confluent cells favors YAP/TAZ nuclear localization and transcriptional activity, while its ectopic expression in subconfluent cells increases YAP/TAZ retention in the cytoplasm. Together, these data suggest that DAB2IP may function as a sensor of cell interactions, contributing to dampening cellular responses to oncogenic inputs in confluent cells and that DAB2IP loss-of-function would facilitate YAP/TAZ activation in intact epithelia, accelerating oncogenic transformation.

Smart Nanocarriers for the Targeted Delivery of Therapeutic Nucleic Acid for Cancer Immunotherapy

A wide variety of therapeutic approaches and technologies for delivering therapeutic agents have been investigated for treating cancer. Recently, immunotherapy has achieved success in cancer treatment. Successful clinical results of immunotherapeutic approaches for cancer treatment were led by antibodies targeting immune checkpoints, and many have advanced through clinical trials and obtained FDA approval. A major opportunity remains for the development of nucleic acid technology for cancer immunotherapy in the form of cancer vaccines, adoptive T-cell therapies, and gene regulation. However, these therapeutic approaches face many challenges related to their delivery to target cells, including their in vivo decay, the limited uptake by target cells, the requirements for nuclear penetration (in some cases), and the damage caused to healthy cells. These barriers can be avoided and resolved by utilizing advanced smart nanocarriers (e.g., lipids, polymers, spherical nucleic acids, metallic nanoparticles) that enable the efficient and selective delivery of nucleic acids to the target cells and/or tissues. Here, we review studies that have developed nanoparticle-mediated cancer immunotherapy as a technology for cancer patients. Moreover, we also investigate the crosstalk between the function of nucleic acid therapeutics in cancer immunotherapy, and we discuss how nanoparticles can be functionalized and designed to target the delivery and thus improve the efficacy, toxicity, and stability of these therapeutics.

Towards a New 3Rs Era in the construction of 3D cell culture models simulating tumor microenvironment

Three-dimensional cell culture technology (3DCC) sits between two-dimensional cell culture (2DCC) and animal models and is widely used in oncology research. Compared to 2DCC, 3DCC allows cells to grow in a three-dimensional space, better simulating the in vivo growth environment of tumors, including hypoxia, nutrient concentration gradients, micro angiogenesis mimicism, and the interaction between tumor cells and the tumor microenvironment matrix. 3DCC has unparalleled advantages when compared to animal models, being more controllable, operable, and convenient. This review summarizes the comparison between 2DCC and 3DCC, as well as recent advances in different methods to obtain 3D models and their respective advantages and disadvantages.

Extracellular matrix remodeling in tumor progression and immune escape: from mechanisms to treatments

The malignant tumor is a multi-etiological, systemic and complex disease characterized by uncontrolled cell proliferation and distant metastasis. Anticancer treatments including adjuvant therapies and targeted therapies are effective in eliminating cancer cells but in a limited number of patients. Increasing evidence suggests that the extracellular matrix (ECM) plays an important role in tumor development through changes in macromolecule components, degradation enzymes and stiffness. These variations are under the control of cellular components in tumor tissue via the aberrant activation of signaling pathways, the interaction of the ECM components to multiple surface receptors, and mechanical impact. Additionally, the ECM shaped by cancer regulates immune cells which results in an immune suppressive microenvironment and hinders the efficacy of immunotherapies. Thus, the ECM acts as a barrier to protect cancer from treatments and supports tumor progression. Nevertheless, the profound regulatory network of the ECM remodeling hampers the design of individualized antitumor treatment. Here, we elaborate on the composition of the malignant ECM, and discuss the specific mechanisms of the ECM remodeling. Precisely, we highlight the impact of the ECM remodeling on tumor development, including proliferation, anoikis, metastasis, angiogenesis, lymphangiogenesis, and immune escape. Finally, we emphasize ECM "normalization" as a potential strategy for anti-malignant treatment.

Hyperthermia-induced stellate cell deactivation to enhance dual chemo and pH-responsive photothermal therapy for pancreatic cancers

For pancreatic ductal adenocarcinoma (PDAC) treatment, the deactivation of pancreatic stellate cells (PSCs) by blocking the transforming growth factor β (TGF-β) pathway is a promising strategy to inhibit stroma, enhance drug penetration, and greatly amplify chemotherapeutic efficacy. It is known that photothermal therapy (PTT) locally depletes stroma and enhances permeability but whether and how PTT reacts in the molecular pathway to induce PSC deactivation in PDAC has rarely been investigated so far. Herein, C-G NPs are synthesized by loading both acid-responsive photothermal molecules and gemcitabine for investigating both the combinatory chemophotothermal therapy and the interaction between the PTT and TGF-β pathway in PDAC. Notably, C-G NPs exhibit tumoral acidic pH-activated PTT and succeeded in deactivating PSCs and suppressing the expression level for both TGF-β and collagen fiber. Furthermore, hyperthermia remodels the tumoral extracellular matrix, significantly improves NP penetration, and boosts the ultimate synergistic chemophotothermal therapeutic efficacy. Importantly, the molecular biology study reveals that hyperthermia leads to the decrease in the mRNA expression of TGF-β1, SMAD2, SMAD3, α-SMA, and Collagen I in the tumor tissue, which is the key to suppress tumor progression. This research demonstrates that combinatory chemophotothermal therapy holds great promise for PDAC treatment.

Laminin-bound integrin α6β4 promotes non-small cell lung cancer progression via the activation of YAP/TAZ signaling pathway

Laminin is an extracellular matrix multidomain trimeric glycoprotein, that has a potential role in tumor progression. Here, we studied the effects of non-small cell lung cancer (NSCLC) cells interaction on laminin and explored the underlying mechanism of laminin associated NSCLC progression. Culture of A549 and NCI-1299 cells on 2D collagen gels (containing laminin) significantly promoted the proliferative and tumorigenic characteristics, as well as cell invasion of tumor cells in vitro. Consistently, comparing the clinical NSCLC tumor tissues, a poor overall survival was observed in patients with high laminin expression. Mechanistically, the expression of integrin α6β4 was required for the pro-tumor effects of laminin. Meanwhile, we showed that the downstream signaling of integrin α6β4, involved the focal adhesion kinase (FAK)/Yes-Associated Protein (YAP)/TAZ signaling pathway. The activation of FAK/YAP/TAZ signaling pathway induced by laminin was validated in tumor tissues from NSCLC patients. Suppression of integrin α6β4/FAK/YAP/TAZ signaling pathway efficiently suppressed the laminin-induced tumor growth, and strengthened the anticancer effects of chemotherapy, describing a novel target for NSCLC treatment.

Identification and Validation of a Potential Stemness-Associated Biomarker in Hepatocellular Carcinoma

Background

Cancer stem cells (CSCs) are typically related to metastasis, recurrence, and drug resistance in malignant tumors. However, the biomarker and mechanism of CSCs need further exploration. This study is aimed at comprehensively depicting the stemness characteristics and identify a potential stemness-associated biomarker in hepatocellular carcinoma (HCC).

Methods

The data of HCC patients from The Cancer Genome Atlas (TCGA) were collected and divided based on the mRNA expression-based stemness index (mRNAsi) in this study. Weighted gene coexpression network analysis (WGCNA) and the protein-protein interaction (PPI) network were performed, and the genes were screened through the Cytoscape software. Then, we constructed a prognostic expression signature using the multivariable Cox analysis and verified using the GEO and ICGC databases. Even more importantly, we used the three-dimensional (3D) fibrin gel to enrich the tumor-repopulating cells (TRCs) to validate the expression of the signature in CSCs by quantitative RT-PCR.

Results

mRNAsi was significantly elevated in tumor and high-mRNAsi score was associated with poor overall survival in HCC. The positive stemness-associated (blue) module with 737 genes were screened based on WGCNA, and Budding uninhibited by benzimidazoles 1 (BUB1) was identified as the hub gene highly related to stemness in HCC. Then, the prognostic value and stemness characteristics were well validated in the ICGC and GSE14520 cohorts. Further analysis showed the expression of BUB1 was elevated in TRCs.

Conclusion

BUB1, as a potential stemness-associated biomarker, could serve as a therapeutic CSCs-target and predicted the clinical outcomes of patients with HCC.

DAB2IP down-regulates HSP90AA1 to inhibit the malignant biological behaviors of colorectal cancer

Background

Studies have shown that DAB2IP inhibits cancer progression, while HSP90AA1 promotes cancer progression. However, the specific regulatory mechanism of DAB2IP and HSP90AA1 in colorectal cancer (CRC) is not clear. Our aim is to investigate the role and mechanism of DAB2IP and HSP90AA1 in the development of CRC.

Methods

We used bioinformation to analyze the interaction between DAB2IP and HSP90AA1 and predict their downstream pathways. Then, a series of in vitro and in vivo experiments were conducted to reveal the role of DAB2IP and HSP90AA1 in the invasion and metastasis of colorectal cancer, and flow cytometry was used to explore their effects on apoptosis.

Results

Loss of DAB2IP was associated with poor prognosis of CRC. In contrast, elevated expression of HSP90AA1 was associated with the malignant behavior of CRC. The present study demonstrated a negative correlation between DAB2IP and HSP90AA1. Using bioinformatic analysis, we scanned SRP9 which was highly expressed in CRC, as a co-related gene of DAB2IP and HSP90AA1. Mechanistically, DAB2IP promoted apoptosis through HSP90AA1/SRP9/ASK1/JNK signaling axis in CRC.

Conclusions

These findings provide evidence that DAB2IP-based therapy may enhance the anticancer effect of HSP90AA1 inhibitors, and combined targeting of DAB2IP and HSP90AA1 may be a powerful treatment strategy to combat CRC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09596-z.

The Molecular Interaction of Collagen with Cell Receptors for Biological Function

Collagen, an extracellular protein, covers the entire human body and has several important biological functions in normal physiology. Recently, collagen from non-human sources has attracted attention for therapeutic management and biomedical applications. In this regard, both land-based animals such as cow, pig, chicken, camel, and sheep, and marine-based resources such as fish, octopus, starfish, sea-cucumber, and jellyfish are widely used for collagen extraction. The extracted collagen is transformed into collagen peptides, hydrolysates, films, hydrogels, scaffolds, sponges and 3D matrix for food and biomedical applications. In addition, many strategic ideas are continuously emerging to develop innovative advanced collagen biomaterials. For this purpose, it is important to understand the fundamental perception of how collagen communicates with receptors of biological cells to trigger cell signaling pathways. Therefore, this review discloses the molecular interaction of collagen with cell receptor molecules to carry out cellular signaling in biological pathways. By understanding the actual mechanism, this review opens up several new concepts to carry out next level research in collagen biomaterials.

Matrix Stiffness Contributes to Cancer Progression by Regulating Transcription Factors

Simple Summary

Matrix stiffness is recognized as a critical factor in cancer progression. Recent studies have shown that matrix stiffening is caused by the accumulation, contraction, and crosslinking of the extracellular matrix by cancer and stromal cells. Cancer and stromal cells respond to matrix stiffness, which determines the phenotypes of these cells. In addition, matrix stiffness activates and/or inactivates specific transcription factors in cancer and stromal cells to regulate cancer progression. In this review, we discuss the mechanisms of cancer stiffening and progression that are regulated by transcription factors responding to matrix stiffness.

Abstract

Matrix stiffness is critical for the progression of various types of cancers. In solid cancers such as mammary and pancreatic cancers, tumors often contain abnormally stiff tissues, mainly caused by stiff extracellular matrices due to accumulation, contraction, and crosslinking. Stiff extracellular matrices trigger mechanotransduction, the conversion of mechanical cues such as stiffness of the matrix to biochemical signaling in the cells, and as a result determine the cellular phenotypes of cancer and stromal cells in tumors. Transcription factors are key molecules for these processes, as they respond to matrix stiffness and are crucial for cellular behaviors. The Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) is one of the most studied transcription factors that is regulated by matrix stiffness. The YAP/TAZ are activated by a stiff matrix and promotes malignant phenotypes in cancer and stromal cells, including cancer-associated fibroblasts. In addition, other transcription factors such as β-catenin and nuclear factor kappa B (NF-κB) also play key roles in mechanotransduction in cancer tissues. In this review, the mechanisms of stiffening cancer tissues are introduced, and the transcription factors regulated by matrix stiffness in cancer and stromal cells and their roles in cancer progression are shown.

Nanog mediated by FAO/ACLY signaling induces cellular dormancy in colorectal cancer cells

Dormant cancer cells drive recurrence and drug resistance, which lead to poor prognosis in colorectal cancer (CRC). The mechanisms that regulate the entry of cancer cells into dormancy remain to be extensively studied. Nanog is a master transcription factor to maintain the self-renewal and pluripotency of stem cells. Since dormant cancer cells are similar to quiescent cancer stem cells, the correlation between dormant state and Nanog in CRC is worth to be explored. Serum deprivation is a common method to establish experimental cellular dormancy model. Here, we verified that serum deprivation-induced CRC cells to enter a cellular dormancy state, characterized by no proliferation, no death, no senescence, resistance to chemotherapy, high expression of dormant markers, metabolic suppression, and recovery to active status. Interestingly, we further identified that Nanog was upregulated in dormant CRC cells. Nanog knockdown could destroy the dormant state of serum-deprived CRC cells while Nanog overexpression could induce dormancy in CRC cells. Mechanistically, Nanog was regulated through a fatty acid oxidation (FAO)/ATP citrate lyase (ACLY)-dependent pathway. FAO increased ACLY expression to promote the synthesis of acetyl-CoA, which was transferred by P300 to accelerate H3K27 acetylation of Nanog promoter. Then, Nanog upregulation increased the transcription of P21 and P27, which promoted the dormancy of CRC cells. Our findings revealed that Nanog could induce cellular dormancy in CRC cells and unlocked a specific mechanism to govern the process.

Intrinsic and Extrinsic Factors Impacting Cancer Stemness and Tumor Progression

Tumor heterogeneity represents an important limitation to the development of effective cancer therapies. The presence of cancer stem cells (CSCs) and their differentiation hierarchies contribute to cancer complexity and confer tumors the ability to grow, resist treatment, survive unfavorable conditions, and invade neighboring and distant tissues. A large body of research is currently focusing on understanding the properties of CSCs, including their cellular and molecular origin, as well as their biological behavior in different tumor types. In turn, this knowledge informs strategies for targeting these tumor initiating cells and related cancer stemness. Cancer stemness is modulated by the tumor microenvironment, which influences CSC function and survival. Several advanced in vitro models are currently being developed to study cancer stemness in order to advance new knowledge of the key molecular pathways involved in CSC self-renewal and dormancy, as well as to mimic the complexity of patients' tumors in pre-clinical drug testing. In this review, we discuss CSCs and the modulation of cancer stemness by the tumor microenvironment, stemness factors and signaling pathways. In addition, we introduce current models that allow the study of CSCs for the development of new targeted therapies.

Promotion of gastric tumor initiating cells in a 3D collagen gel culture model via YBX1/SPP1/NF-κB signaling

Background

The high potential for tumor recurrence and chemoresistance is a major challenge of clinical gastric cancer treatment. Increasing evidence suggests that the presence of tumor initiating cells (TICs) is the principal cause of tumor recurrence and chemoresistance. However, the underlying mechanism of TIC development remains controversial.

Methods

To identify novel molecular pathways in gastric cancer, we screened the genomic expression profile of 155 gastric cancer patients from the TCGA database. We then described an improved 3D collagen I gels and tested the effects of collagen on the TIC phenotype of gastric cells using colony formation assay, transwell assay, and nude mouse models. Additionally, cell apoptosis assay was performed to examine the cytotoxicity of 5-fluorine and paclitaxel on gastric cancer cells cultured in 3D collagen I gels.

Results

Elevated expression of type I collagen was observed in tumor tissues from high stage patients (stage T3–T4) when compared to the low stage group (n=10, stage T1–T2). Furthermore, tumor cells seeded in a low concentration of collagen gels acquired TIC-like phenotypes and revealed enhanced resistance to chemotherapeutic agents, which was dependent on an integrin β1 (ITGB1)/Y-box Binding Protein 1 (YBX1)/Secreted Phosphoprotein 1 (SPP1)/NF-κB signaling pathway. Importantly, inhibition of ITGB1/NF-κB signaling efficiently reversed the chemoresistance induced by collagen and promoted anticancer effects in vivo.

Conclusions

Our findings demonstrated that type I collagen promoted TIC-like phenotypes and chemoresistance through ITGB1/YBX1/SPP1/NF-κB pathway, which may provide novel insights into gastric cancer therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02307-x.

DOC-2/DAB2 interactive protein destabilizes c-Myc to impair the growth and self-renewal of colon tumor-repopulating cells

Colorectal carcinoma (CRC) remains a huge challenge in clinical treatment due to tumor metastasis and recurrence. Stem cell-like colon tumor-repopulating cells (TRCs) are a subpopulation of cancer cells with highly tumorigenic and chemotherapy resistant properties. The core transcription factor c-Myc is essential for maintaining cancer stem-like cell phenotypes, yet its roles and regulatory mechanisms remain unclear in colon TRCs. We report that elevated c-Myc protein supported formation and growth of TRC spheroids. The tumor suppressor DOC-2/DAB2 interactive protein (DAB2IP) suppressed c-Myc expression to inhibit TRC expansion and self-renewal. Particularly, DAB2IP disrupted c-Myc stability through glycogen synthase kinase 3β/protein phosphatase 2A-B56α-mediated phosphorylation and dephosphorylation cascade on c-Myc protein, leading to its eventual degradation through the ubiquitin-proteasome pathway. The expression of DAB2IP was negatively correlated with c-Myc in CRC specimens. Overall, our results improved mechanistic insight into how DAB2IP suppressed TRC growth and self-renewal.

Thromboelastometric Analysis of Anticancer Cerrena unicolor Subfractions Reveal Their Potential as Fibrin Glue Drug Carrier Enhancers

In this study, the influence of two subfractions (with previously proven anti-cancer properties) isolated from wood rot fungus Cerrena unicolor on the formation of a fibrin clot was investigated in the context of potential use as fibrin glue and sealant enhancers and potential wound healing agents. With the use of ROTEM thromboelastometry, we demonstrated that, in the presence of fibrinogen and thrombin, the S6 fraction accelerated the formation of a fibrin clot, had a positive effect on its elasticity modulus, and enhanced the degree of fibrin cross-linking. The S5 fraction alone showed no influence on the fibrin coagulation process; however, in the presence of fibrin, it exhibited a decrease in anti-proliferative properties against the HT-29 line, while it increased the proliferation of cells in general at a concentration of 100 µg/mL. Both fractions retained their proapoptotic properties to a lesser degree. In combination with the S6 fraction in the ratio of 1:1 and 1:3, the fractions contributed to increased inhibition of the activity of matrix metalloproteinases (MMPs). This may suggest anti-metastatic activity of the combined fractions. In conclusion, the potential of the fractions isolated from the C. unicolor secretome to be used as a means of improving the wound healing process was presented. The potential for delivering agents with cytostatic properties introduced far from the site of action or exerting a pro-proliferative effect at the wound site with the aid of a fibrin sealant was demonstrated.

Extracellular matrix and its therapeutic potential for cancer treatment

The extracellular matrix (ECM) is one of the major components of tumors that plays multiple crucial roles, including mechanical support, modulation of the microenvironment, and a source of signaling molecules. The quantity and cross-linking status of ECM components are major factors determining tissue stiffness. During tumorigenesis, the interplay between cancer cells and the tumor microenvironment (TME) often results in the stiffness of the ECM, leading to aberrant mechanotransduction and further malignant transformation. Therefore, a comprehensive understanding of ECM dysregulation in the TME would contribute to the discovery of promising therapeutic targets for cancer treatment. Herein, we summarized the knowledge concerning the following: (1) major ECM constituents and their functions in both normal and malignant conditions; (2) the interplay between cancer cells and the ECM in the TME; (3) key receptors for mechanotransduction and their alteration during carcinogenesis; and (4) the current therapeutic strategies targeting aberrant ECM for cancer treatment.

Matrix stiffness promotes glioma cell stemness by activating BCL9L/Wnt/β-catenin signaling

Matrix stiffness is a key physical characteristic of the tumor microenvironment and correlates tightly with tumor progression. Here, we explored the association between matrix stiffness and glioma development. Using atomic force microscopy, we observed higher matrix stiffness in highly malignant glioma tissues than in low-grade/innocent tissues. In vitro and in vivo analyses revealed that culturing glioma cells on stiff polyacrylamide hydrogels enhanced their proliferation, tumorigenesis and CD133 expression. Greater matrix stiffness could obviously up-regulated the expression of BCL9L, thereby promoting the activation of Wnt/β-catenin signaling and ultimately increasing the stemness of glioma cells. Inhibiting Wnt/β-catenin signaling using gigantol consistently improved the anticancer effects of chemotherapy and radiotherapy in mice with subcutaneous glioma tumors. These findings demonstrate that a stiffer matrix increases the stemness of glioma cells by activating BCL9L/Wnt/β-catenin signaling. Moreover, we have provided a potential strategy for clinical glioma treatment by demonstrating that gigantol can improve the effectiveness of traditional chemotherapy/radiotherapy by suppressing Wnt/β-catenin signaling.

RNAi mediated silencing of Nanog expression suppresses the growth of human colorectal cancer stem cells

Colorectal cancer (CRC) is the third most common cancer in the world known for its poor recurrence-free prognosis. Previous studies have shown that it is closely linked with cancer stem cells (CSCs), which have self-renewal potential and the capacity to differentiate into diverse populations. Nanog is an important transcription factor that functions to maintain the self-renewal and proliferation of embryonic stem cells; however, many recent studies have shown that Nanog is also highly expressed in many cancer stem cells. To investigate whether Nanog plays a crucial role in maintaining the stemness of colorectal CSCs, RNA interference was used to downregulate Nanog expression in the CRC stem cell line, EpCAM+CD44+HCT-116 cells (CCSCs). We examined the anti-tumor function of Nanog in vitro and in vivo, using small interfering RNA. Our results revealed that the Nanog mRNA expression level in CCSCs was higher than that in HCT-116 cells. We found that the depletion of Nanog inhibited proliferation and promoted apoptosis in CCSCs. In addition, the invasive ability of CCSCs was markedly restricted when Nanog was silenced by small interfering RNA. Furthermore, we found that the silencing of Nanog decreased tumor size and weight and improved the survival rate of tumor-bearing mice. In conclusion, these findings collectively demonstrate that Nanog, which is highly expressed in CRC stem cells, is a key factor in the development of tumor growth, and it may serve as a potential marker of prognosis and a novel and effective therapeutic target for the treatment of CRC.

Remodeling cancer stemness by collagen/fibronectin via the AKT and CDC42 signaling pathway crosstalk in glioma

Cancer development is a complex set of proliferative progression, which arises in most cases via multistep pathways associated with various factors, including the tumor microenvironment and extracellular matrix. However, the underlying mechanisms of cancer development remain unclear and this study aimed to explore the role of extracellular matrix in glioma progression.

Methods: The expression of type I collagen and fibronectin in tumor tissues from glioma patients was examined by immunofluorescence staining. The correlations between collagen/fibronectin and glioma progression were then analyzed. A 3D collagen/fibronectin cultured system was established for tumor cells culture in vitro. Quantitative, real-time PCR and western blot were used to detect PI3K/ATK and CDC42 signals associated proteins expression in glioma. We used in vitro Cell Counting Kit-8, colony formation, and tumorigenesis assays to investigate the function of PI3K/AKT and CDC42 signals associated proteins. A xenograft glioma mice model was also used to study the anticancer effects of integrin inhibitor in vivo.

Results: Our study demonstrated that type I collagen and fibronectin collaborate to regulate glioma cell stemness and tumor growth. In a 3D collagen/fibronectin culture model, glioma cells acquired tumorigenic potential and revealed strengthened proliferative characteristics. More significantly, collagen/fibronectin could facilitate the activation of PI3K/AKT/SOX2 and CDC42/YAP-1/NUPR1/Nestin signaling pathways via integrin αvβ3, eliciting sustained tumor growth and cancer relapse. Combination of the integrin signaling pathway inhibitor and the chemotherapeutic agent efficiently suppressed glioma cell proliferation and tumorigenic ability.

Conclusion: We demonstrated that type I collagen and fibronectin could collaborate to promote glioma progression through PI3K/AKT/SOX2 and CDC42/YAP-1/NUPR1/Nestin signaling pathways. Blockade of the upstream molecular integrin αvβ3 revealed improved outcome in glioma therapy, which provide new insights for eradicating tumors and reducing glioma cancer relapse.

Cancer Stem Cell Microenvironment Models with Biomaterial Scaffolds In Vitro

Defined by its potential for self-renewal, differentiation and tumorigenicity, cancer stem cells (CSCs) are considered responsible for drug resistance and relapse. To understand the behavior of CSC, the effects of the microenvironment in each tissue are a matter of great concerns for scientists in cancer biology. However, there are many complicated obstacles in the mimicking the microenvironment of CSCs even with current advanced technology. In this context, novel biomaterials have widely been assessed as in vitro platforms for their ability to mimic cancer microenvironment. These efforts should be successful to identify and characterize various CSCs specific in each type of cancer. Therefore, extracellular matrix scaffolds made of biomaterial will modulate the interactions and facilitate the investigation of CSC associated with biological phenomena simplifying the complexity of the microenvironment. In this review, we summarize latest advances in biomaterial scaffolds, which are exploited to mimic CSC microenvironment, and their chemical and biological requirements with discussion. The discussion includes the possible effects on both cells in tumors and microenvironment to propose what the critical factors are in controlling the CSC microenvironment focusing the future investigation. Our insights on their availability in drug screening will also follow the discussion.

Is There Such a Thing as a Genuine Cancer Stem Cell Marker? Perspectives from the Gut, the Brain and the Dental Pulp

The conversion of healthy stem cells into cancer stem cells (CSCs) is believed to underlie tumor relapse after surgical removal and fuel tumor growth and invasiveness. CSCs often arise from the malignant transformation of resident multipotent stem cells, which are present in most human tissues. Some organs, such as the gut and the brain, can give rise to very aggressive types of cancers, contrary to the dental pulp, which is a tissue with a very remarkable resistance to oncogenesis. In this review, we focus on the similarities and differences between gut, brain and dental pulp stem cells and their related CSCs, placing a particular emphasis on both their shared and distinctive cell markers, including the expression of pluripotency core factors. We discuss some of their similarities and differences with regard to oncogenic signaling, telomerase activity and their intrinsic propensity to degenerate to CSCs. We also explore the characteristics of the events and mutations leading to malignant transformation in each case. Importantly, healthy dental pulp stem cells (DPSCs) share a great deal of features with many of the so far reported CSC phenotypes found in malignant neoplasms. However, there exist literally no reports about the contribution of DPSCs to malignant tumors. This raises the question about the particularities of the dental pulp and what specific barriers to malignancy might be present in the case of this tissue. These notable differences warrant further research to decipher the singular properties of DPSCs that make them resistant to transformation, and to unravel new therapeutic targets to treat deadly tumors.

Cutting the Brakes on Ras-Cytoplasmic GAPs as Targets of Inactivation in Cancer

Simple Summary

GTPase-Activating Proteins (RasGAPs) are a group of structurally related proteins with a fundamental role in controlling the activity of Ras in normal and cancer cells. In particular, loss of function of RasGAPs may contribute to aberrant Ras activation in cancer. Here we review the multiple molecular mechanisms and factors that are involved in downregulating RasGAPs expression and functions in cancer. Additionally, we discuss how extracellular stimuli from the tumor microenvironment can control RasGAPs expression and activity in cancer cells and stromal cells, indirectly affecting Ras activation, with implications for cancer development and progression.

Abstract

The Ras pathway is frequently deregulated in cancer, actively contributing to tumor development and progression. Oncogenic activation of the Ras pathway is commonly due to point mutation of one of the three Ras genes, which occurs in almost one third of human cancers. In the absence of Ras mutation, the pathway is frequently activated by alternative means, including the loss of function of Ras inhibitors. Among Ras inhibitors, the GTPase-Activating Proteins (RasGAPs) are major players, given their ability to modulate multiple cancer-related pathways. In fact, most RasGAPs also have a multi-domain structure that allows them to act as scaffold or adaptor proteins, affecting additional oncogenic cascades. In cancer cells, various mechanisms can cause the loss of function of Ras inhibitors; here, we review the available evidence of RasGAP inactivation in cancer, with a specific focus on the mechanisms. We also consider extracellular inputs that can affect RasGAP levels and functions, implicating that specific conditions in the tumor microenvironment can foster or counteract Ras signaling through negative or positive modulation of RasGAPs. A better understanding of these conditions might have relevant clinical repercussions, since treatments to restore or enhance the function of RasGAPs in cancer would help circumvent the intrinsic difficulty of directly targeting the Ras protein.

Downregulation of RIG-I mediated by ITGB3/c-SRC/STAT3 signaling confers resistance to interferon-α-induced apoptosis in tumor-repopulating cells of melanoma

BACKGROUND

Interferon-α (IFN-α) plays a pivotal role in host antitumor immunity, and the evasion of IFN-α signaling pathway can lead to IFN-α resistance during the treatment of cancer. Although the interplay between IFN-α and tumor cells has been extensively investigated in differentiated tumor cells, much less attention has been directed to tumor-repopulating cells (TRCs).

METHODS

Three-dimentional soft fibrin matrix was used to select and grow highly malignant and tumorigenic melanoma TRCs. The regulation of integrin β3 (ITGB3)-c-SRC-STAT signaling pathway in melanoma TRCs was investigated both in vitro and in vivo. The relevant mRNA and protein expression levels were analyzed by qRT-PCR and western blot analysis. Immunoprecipitation and chromatin immunoprecipitation (ChIP) followed by qPCR (ChIP-qPCR) assays were performed to detect protein-protein and protein-DNA interactions. The clinical impacts of retinoic acid inducible gene-I (RIG-I) were assessed in melanoma datasets obtained from The Cancer Genome Atlas and Gene Expression Omnibus profiles.

RESULTS

IFN-α-induced apoptosis was decreased in melanoma TRCs. Compared with conventional flask-cultured cells, IFN-α-mediated STAT1 activation was diminished in melanoma TRCs. Decreased expression of RIG-I in melanoma TRCs led to diminished activation of STAT1 via enhancing the interaction between Src homology region 2 domain-containing phosphatase-1 and STAT1. In addition, low expression levels of RIG-I correlated with poor prognosis in patients with melanoma. STAT3 was highly phosphorylated in TRCs and knockdown of STAT3 reversed the downregulation of RIG-I in TRCs. Knockdown of STAT3 resulted in STAT1 activation and increased expression of the pro-apoptosis genes in IFN-α-treated TRCs. Combined treatment of STAT3 inhibitor and IFN-α increased the apoptosis rate of TRCs. Disruption of ITGB3/c-SRC/STAT3 signaling pathway significantly elevated the efficiency of IFN-α-induced apoptosis of TRCs.

CONCLUSIONS

In melanoma TRCs, ITGB3-c-SRC-STAT3 pathway caused RIG-I repression and then affect STAT1 activation to cause resistance to IFN-α-induced apoptosis. RIG-I is a prognostic marker in patients with melanoma. Combination of STAT3 inhibitor and IFN-α could enhance the efficacy of melanoma treatment. Our findings may provide a new concept of combinatorial treatment for future immunotherapy.