EMT Transition States during Tumor Progression and Metastasis

DIF-1 inhibits growth and metastasis of triple-negative breast cancer through AMPK-mediated inhibition of the mTORC1-S6K signaling pathway

We have previously reported that the differentiation-inducing factor-1 (DIF-1), a compound identified in Dictyostelium discoideum, suppresses the growth of MCF-7 breast cancer cells by inactivating p70 ribosomal protein S6 kinase (p70S6K). Therefore, we first examined whether the same mechanism operates in other breast cancer cells, especially triple-negative breast cancer (TNBC), the most aggressive and refractory phenotype of breast cancer. We also investigated the mechanism by which DIF-1 suppresses p70S6K by focusing on the AMPK-mTORC1 system. We found that DIF-1 induces phosphorylation of AMPK and Raptor and dephosphorylation of p70S6K in multiple TNBC cell lines. Next, we examined whether AMPK-mediated inhibition of p70S6K leads to the suppression of proliferation and migration/infiltration of TNBC cells. DIF-1 significantly reduced the expression levels of cyclin D1 by suppressing the translation of STAT3 and strongly suppressed the expression levels of Snail, which led to the suppression of growth and motility, respectively. Finally, we investigated whether DIF-1 exerts anticancer effects on TNBC in vivo. Intragastric administration of DIF-1 suppressed tumor growth and spontaneous lung metastasis of 4T1-Luc cells injected into the mammary fat pad of BALB/c mice. DIF-1 is expected to lead to the development of anticancer drugs, including anti-TNBC, by a novel mechanism.

Endocytosis in the context-dependent regulation of individual and collective cell properties

Endocytosis allows cells to transport particles and molecules across the plasma membrane. In addition, it is involved in the termination of signalling through receptor downmodulation and degradation. This traditional outlook has been substantially modified in recent years by discoveries that endocytosis and subsequent trafficking routes have a profound impact on the positive regulation and propagation of signals, being key for the spatiotemporal regulation of signal transmission in cells. Accordingly, endocytosis and membrane trafficking regulate virtually every aspect of cell physiology and are frequently subverted in pathological conditions. Two key aspects of endocytic control over signalling are coming into focus: context-dependency and long-range effects. First, endocytic-regulated outputs are not stereotyped but heavily dependent on the cell-specific regulation of endocytic networks. Second, endocytic regulation has an impact not only on individual cells but also on the behaviour of cellular collectives. Herein, we will discuss recent advancements in these areas, highlighting how endocytic trafficking impacts complex cell properties, including cell polarity and collective cell migration, and the relevance of these mechanisms to disease, in particular cancer.

Triptolide suppresses the growth and metastasis of non-small cell lung cancer by inhibiting β-catenin-mediated epithelial-mesenchymal transition

Non-small cell lung cancer (NSCLC) is characterized by a high incidence of metastasis and poor survival. As epithelial-mesenchymal transition (EMT) is well recognized as a major factor initiating tumor metastasis, developing EMT inhibitor could be a feasible treatment for metastatic NSCLC. Recent studies show that triptolide isolated from Tripterygium wilfordii Hook F attenuated the migration and invasion of breast cancer, colon carcinoma, and ovarian cancer cells, and EMT played important roles in this process. In the present study we investigated the effect of triptolide on the migration and invasion of NSCLC cell lines. We showed that triptolide (0.5, 1.0, 2.0 nM) concentration-dependently inhibited the migration and invasion of NCI-H1299 cells. Triptolide treatment concentration-dependently suppressed EMT in NCI-H1299 cells, evidenced by significantly elevated E-cadherin expression and reduced expression of ZEB1, vimentin, and slug. Furthermore, triptolide treatment suppressed β-catenin expression in NCI-H1299 and NCI-H460 cells, overexpression of β-catenin antagonized triptolide-caused inhibition on EMT, whereas knockout of β-catenin enhanced the inhibitory effect of triptolide on EMT. Administration of triptolide (0.75, 1.5 mg/kg per day, ip, every 2 days) for 18 days in NCI-H1299 xenograft mice dose-dependently suppressed the tumor growth, restrained EMT, and decreased lung metastasis, as evidence by significantly decreased expression of mesenchymal markers, increased expression of epithelial markers as well as reduced number of pulmonary lung metastatic foci. These results demonstrate that triptolide suppresses NSCLC metastasis by targeting EMT via reducing β-catenin expression. Our study implies that triptolide may be developed as a potential agent for the therapy of NSCLC metastasis.

Knockdown of circ_0001883 may inhibit epithelial-mesenchymal transition in laryngeal squamous cell carcinoma via the miR-125-5p/PI3K/AKT axis

Laryngeal squamous cell carcinoma (LSCC) is a malignant tumor with increasing incidence and poor prognosis. Circular RNAs (circRNAs) are known to modulate tumorigenesis and cancer development that may function through microRNAs (miRs). The aim of the present study was to investigate the functional roles of circ_0001883 in LSCC and the underlying molecular mechanism. The expression of circ_0001883 was upregulated and measured using reverse transcription-quantitative PCR (RT-qPCR) and RNase R. miR-125b-5p expression was downregulated in LSCC tissues and cells as determined using RT-qPCR. Subsequently, knockdown of circ_0001883 inhibited LSCC cell migration, invasion and epithelial-mesenchymal transition (EMT), which were tested by wound healing assays, Transwell assays and western blotting, respectively. Bioinformatics analysis predicted that circ_0001883 was a sponge of miR-125b-5p, which was verified using a dual-luciferase reporter assay. Knockdown of circ_0001883 played a functional role by sponging miR-125b-5p. Additionally, circ_0001883 and miR-125b-5p influenced phosphorylation of PI3K and AKT, detected via western blotting. In an in vivo study, knockdown of circ_0001883 reduced tumor volume and weight in mice, along with enhanced miR-125b-5p and E-cadherin expression levels, and decreased N-cadherin, phosphorylated (p)-PI3K/PI3K and p-AKT/AKT ratios. In conclusion, knockdown of circ_0001883 inhibited cell migration, invasion and EMT of LSCC by sponging miR-125b-5p. This is hypothesized to be via the PI3K/AKT signaling pathway, which suggested that circ_0001883 has potential for LSCC therapy.

E2A Modulates Stemness, Metastasis, and Therapeutic Resistance of Breast Cancer

Cancer stem cells (CSC) are considered responsible for tumor initiation, therapeutic resistance, and metastasis. A comprehensive knowledge of the mechanisms governing the acquisition and maintenance of cancer stemness is crucial for the development of new therapeutic approaches in oncology. E2A basic helix-loop-helix (bHLH) transcription factors are associated with epithelial-mesenchymal transition (EMT) and tumor progression, but knowledge of their functional contributions to cancer biology is still limited. Using a combination of in vivo and in vitro analyses in a novel PyMT-E2A conditional knockout mouse model and derived primary tumor cell lines, we report here an essential role of E2A in stemness, metastasis, and therapeutic resistance in breast cancer. Targeted deletion of E2A in the mammary gland impaired tumor-initiating ability and dedifferentiation potential and severely compromised metastatic competence of PyMT-driven mammary tumors. Mechanistic studies in PyMT-derived cell lines indicated that E2A actions are mediated by the upregulation of Snai1 transcription. Importantly, high E2A and SNAIL1 expression occurred in aggressive human basal-like breast carcinomas, highlighting the relevance of the E2A-Snail1 axis in metastatic breast cancer. In addition, E2A factors contributed to the maintenance of genomic integrity and resistance to PARP inhibitors in PyMT and human triple-negative breast cancer cells. Collectively, these results support the potential for E2A transcription factors as novel targets worthy of translational consideration in breast cancer. SIGNIFICANCE: These findings identify key functions of E2A factors in breast cancer cell stemness, metastasis, and drug resistance, supporting a therapeutic vulnerability to targeting E2A proteins in breast cancer.

lncRNA FEZF1-AS1 regulates biological behaviors of cervical cancer by targeting miRNA-1254

AIM

The purpose of this research was to evaluate lncRNA FEZF1-AS1 in cervical cancer development and clinical significance.

MATERIALS AND METHODS

Collecting cervical cancer tissues, measuring FEZF1-AS1 expression, and analysis correlation between FEZF1-AS1 and prognosis. In cell vitro study, using MTT assay to measure cell proliferation, evaluating cell apoptosis by flow cytometry, measuring cell invasion and migration by Transwell and wound healing assay; lncRNA FEZF1-AS1 and miR-1254 gene expressions were evaluated by RT-qPCR assay; relative protein (Smurf1, E-cadherin, Vimentin, N-cadherin, AKT, p-AKT, c-Myc, and ZEB1) expressions were measured by Western blot assay. The correlation among FEZF1-AS1, miR-1254, and Smurf1 were analysis by dual luciferase reporter gene assay.

RESULTS

By clinical analysis, lncRNA FEZF1-AS1 was high expression in cervical cancer tissues and high expression was closely correlated with poor prognosis in cervical cancer patients. In vitro study, the SiHa and HeLa cell biologically including cell proliferation, migration, and invasion of si-FEZF1-AS1 group which knockdown lncRNA FEZF1-AS1 were significantly depressed (p < .001, respectively). However, with miR-1254 expression inhibiting, the cell biological activities were significantly increased in si-FEZF1-AS1+miRNA inhibitor groups (p < .001, respectively).

CONCLUSION

lncRNA FEZF1-AS1 might be an oncological role in cervical cancer; lncRNA FEZF1-AS1 knockdown had antitumor effects with miR-1254 activating in cervical cancer by in vitro study.

Tackling TAMs for Cancer Immunotherapy: It's Nano Time

The tumor microenvironment (TME) is a highly complex environment that surrounds tumors. Interactions between cancer cells/non-cancerous cells and cells/non-cell components in the TME support tumor initiation, development, and metastasis. Of the cell types in the TME, tumor-associated macrophages (TAMs) have gained attention owing to their crucial roles in supporting tumors and conferring therapy resistance. Recent developments in nanotechnology raise opportunities for the application of nano targeted drug-delivery systems (Nano-TDDS) in cancer therapy. We focus our discussion on current knowledge of TAMs, and describe recent examples of Nano-TDDS-based TAM modulation, highlighting strategies to overcome in vivo delivery barriers associated with the TME and their potential for clinical translation.

Carvacrol Suppresses Human Osteosarcoma Cells via the Wnt/β-Catenin Signaling Pathway

BACKGROUND

Carvacrol is a monoterpenic phenol extracted from traditional Chinese herbs, including oregano and thyme. Currently, carvacrol has been widely studied for its therapeutic role in central nervous system diseases, liver diseases and digestive system cancer.

OBJECTIVE

However, the role of carvacrol in osteosarcoma and its underlying molecular mechanism remain elusive. Here, we aimed to examine the anticancer effects of carvacrol on osteosarcoma.

METHODS

The effects of carvacrol on the osteosarcoma proliferation capacity were revealed by CCK-8 and colony formation assays. Flow cytometry and Hoechst assays were used to determine the effects of carvacrol on osteosarcoma cell apoptosis. The effect of carvacrol on migration and invasion of osteosarcoma cells was determined by wound healing and transwell tests. Protein expression was evaluated by WB assays. The suppressive effects of carvacrol on osteosarcoma in vivo were examined by a xenograft animal model, immunohistochemistry and HE staining.

RESULTS

We demonstrated that carvacrol treatment reduced viability and inhibited the colony formation of U2OS and 143B cells in a concentration-dependent manner. Apoptotic cell number increased after exposure to carvacrol. Meanwhile, the expression of Bax increased, and that of Bcl-2 decreased by carvacrol treatment. In addition, the MMP-9 expression and migration and invasion of 143B and U2OS cells were inhibited by carvacrol. We also found that these carvacrol-induced effects on osteosarcoma are associated with the regulation of the Wnt/β-catenin signaling pathway.

CONCLUSION

Our findings suggest that carvacrol suppresses proliferation, migration, invasion and promotes apoptosis in osteosarcoma cells, in part by regulating the Wnt/β-catenin signaling pathway.

Epithelial plasticity, epithelial-mesenchymal transition, and the TGF-β family

Epithelial cells repress epithelial characteristics and elaborate mesenchymal characteristics to migrate to other locations and acquire new properties. Epithelial plasticity responses are directed through cooperation of signaling pathways, with TGF-β and TGF-β-related proteins playing prominent instructive roles. Epithelial-mesenchymal transitions (EMTs) directed by activin-like molecules, bone morphogenetic proteins, or TGF-β regulate metazoan development and wound healing and drive fibrosis and cancer progression. In carcinomas, diverse EMTs enable stem cell generation, anti-cancer drug resistance, genomic instability, and localized immunosuppression. This review discusses roles of TGF-β and TGF-β-related proteins, and underlying molecular mechanisms, in epithelial plasticity in development and wound healing, fibrosis, and cancer.

Cytoskeleton Response to Ionizing Radiation: A Brief Review on Adhesion and Migration Effects

The cytoskeleton is involved in several biological processes, including adhesion, motility, and intracellular transport. Alterations in the cytoskeletal components (actin filaments, intermediate filaments, and microtubules) are strictly correlated to several diseases, such as cancer. Furthermore, alterations in the cytoskeletal structure can lead to anomalies in cells’ properties and increase their invasiveness. This review aims to analyse several studies which have examined the alteration of the cell cytoskeleton induced by ionizing radiations. In particular, the radiation effects on the actin cytoskeleton, cell adhesion, and migration have been considered to gain a deeper knowledge of the biophysical properties of the cell. In fact, the results found in the analysed works can not only aid in developing new diagnostic tools but also improve the current cancer treatments.

Ophiopogonin B inhibits migration and invasion in non-small cell lung cancer cells through enhancing the interaction between Axin and β-catenin

Ophiopogonin B (OP-B), a kind of saponin compound that exists in Radix Ophiopogonis is frequently adopted for the treatment of lung disease as traditional Chinese medicine. The present work aimed to explore the anti-tumor activity of OP-B on non-small cell lung carcinoma (NSCLC) and its possible mechanism. We found that OP-B-treated cells suppressed the viability and proliferation of cells depending on its concentration, as assayed by MTT and Alamar Blue (IC50 were 14.22 ± 1.94, 12.14 ± 2.01, and 16.11 ± 1.83 μM in A549, NCI-H1299, and NCI-H460 cells, respectively). Then, the suppressive effect of OP-B on the invasion and migration of NSCLC was observed through wound healing and Transwell assays, and the epithelial-mesenchymal transition (EMT) markers was detected by immunofluorescence and western blotting. In addition, a dose-dependent reduction of β-catenin both within cytoplasm and nucleus was observed, and the downstream proteins cyclin D1 and c-Myc of Wnt/β-catenin pathway were also reduced. We further constructed β-catenin-overexpression cell models to reveal the underlying mechanism. The results showed that 10 μM of OP-B notably reduced β-catenin protein levels, as well as cell migration and invasion. In spite of the increasement of β-catenin, activation of Wnt pathway and EMT progression, knockdown of Axin leaded to de-function of OP-B on cell metastasis. Taken together, OP-B reduced NSCLC migration and invasion by strengthening the Axin/β-catenin interaction and reducing β-catenin protein translocation.

FAM83G promotes proliferation, invasion, and metastasis by regulating PI3K/AKT signaling in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) has received extensive attention from clinical and scientific researchers due to its high incidence and refractory nature. Searching for HCC prognostic markers and gene therapy targets are key research efforts. The FAM83 protein family has been reported to promote tumor growth and metastasis in a variety of tumors, and many of its members are closely related to HCC. Multiple public databases showed that FAM83G is highly expressed in HCC patients and is associated with poor prognosis, but there is currently no relevant research evidence to verify its exact role in HCC. Through clinical data analysis, we found that increased expression of FAM83G is associated with early HCC metastasis and a high recurrence rate and indicates a poor survival rate. Both in vivo and in vitro experiments confirmed that FAM83G overexpression significantly promoted the proliferation, migration, and invasion of HCC cells, while inhibiting its expression reversed the above results. Mechanistic analysis indicated that FAM83G overexpression was accompanied by over-activation of PI3K/AKT pathway signaling, a combined increase of Cyclin D1 protein and decrease of p21 protein, and increased expression of EMT-related signal, which was manifested in the decrease of E-cadherin and the increase of N-cadherin and snail. Finally, we found that FAM83G activated PI3K/AKT signaling by directly binding with the PI3K-p85 subunit to promote its phosphorylation. In conclusion, FAM83G, as a tumor-promoting factor, can predict the poor prognosis of HCC patients and can significantly promote the proliferation, invasion, and migration of HCC cells by stimulating the PI3K/AKT signaling pathway and related downstream signals.

CUX1 Facilitates the Development of Oncogenic Properties Via Activating Wnt/β-Catenin Signaling Pathway in Glioma

Background: Homeobox cut like 1 (CUX1), which often presents aberrated expression in many cancer cells, exerts a crucial role in tumorigenesis. Evidence describing CUX1 in gliomagenesis is scarce, and the effects of CUX1 on the Wnt/β-catenin pathway have not been reported. Our study aimed to explore the biological functions and molecular mechanisms involved in CUX1 activity in glioma.

Methods: Datasets for bioinformatics analysis were obtained from the GEO, TCGA, CGGA, GTEX and CCLE databases. qRT-PCR, western blotting (WB), and immunohistochemistry (IHC) assays were used to investigate the expression patterns of CUX1 among glioma and brain tissues. CUX1 knockdown and overexpression vectors were transfected into glioma cell lines, the CCK-8, clone formation assay, wound healing, Transwell assay, and flow cytometry were performed to detect changes in cell viability, invasiveness, and the cell cycle. WB and immunofluorescence (IF) assays were used to explore changes in cell cycle-related and Wnt/β-catenin signaling protein levels.

Results: Overexpression of CUX1 was identified in glioma tissues, and especially in glioblastoma (GBM), when compared to normal controls and correlated with poor prognosis. In comparison with untreated cells, TJ905 glioma cells overexpressing CUX1 showed higher proliferation and invasion abilities and S phase cell-cycle arrest, while the knockdown of CUX1 suppressed cell invasive ability and induced G1 phase arrest. Active Wnt/β-catenin signaling was enriched and clustered in a CUX1-associated GSEA/GSVA analysis. IF and WB assays indicated that CUX1 regulated the distribution of Axin2/β-catenin in glioma cells and regulated the expression of proteins downstream of the Wnt/β-catenin signaling pathway, suggesting that CUX1 served as an upstream positive regulator of the Wnt/β-catenin pathway. Finally, the knockdown of Axin2 or β-catenin could reverse the tumor-promoting effects caused by CUX1 overexpression, suggesting that CUX1 induced gliomagenesis and malignant phenotype by activating the Wnt/β-catenin signaling pathway.

Conclusion: Our data suggested that the transcription factor CUX1 could be a novel therapeutic target for glioma with gene therapy.

ARID1A regulates E-cadherin expression in colorectal cancer cells: a promising candidate therapeutic target

BACKGROUND

Metastasis is a major cause of death in Colorectal cancer (CRC) patients, and the Epithelial-mesenchymal transition (EMT) has been known to be a crucial event in cancer metastasis. Downregulated expression of AT-rich interaction domain-containing protein 1A (ARID1A), a bona fide tumor suppressor gene, plays an important role in promoting EMT and CRC metastasis, but the underlying molecular mechanisms remain poorly understood. Here, we evaluated the impact of ARID1A knockdown and overexpression on the expression of EMT‑related genes, E-cadherin and β-catenin, in human CRC cells.

METHODS AND RESULTS

The expression levels of ARID1A, E-cadherin and β-catenin in CRC cell lines were detected via real-time quantitative PCR (qPCR) and western blot. ARID1A overexpression and shRNA-mediated knockdown were performed to indicate the effect of ARID1A expression on E-cadherin and β-catenin expression in CRC cell lines. The effect of ARID1A knockdown on the migration ability of HCT116 cells was assessed using wound-healing assay. We found that the mRNA and protein expression of adhesive protein E-cadherin was remarkably downregulated in response to shRNA-mediated ARID1A knockdown in HCT116 and HT29 cells. Conversely, overexpression of ARID1A in SW48 cells significantly increased E-cadherin expression. In addition, ARID1A silencing promoted the migration of HCT116 cells. ARID1A knockdown and overexpression did not alter the level of β-catenin expression.

CONCLUSIONS

Our study demonstrates that E-cadherin levels were closely correlated with ARID1A expression. Thus, ARID1A downregulation may promote CRC metastasis through decreasing EMT‑related protein E-cadherin and promoting epithelial cell movement. ARID1A could represent a promising candidate therapeutic target for CRC.

ADAM15 correlates with prognosis, immune infiltration and apoptosis in hepatocellular carcinoma

ADAM15 is highly expressed in malignant tumors and is correlated with tumor progression. However, the role of ADAM15 in hepatocellular carcinoma (HCC) remains unclear. In the study, our results indicated that ADAM15 was highly expressed in HCC tissues and cells compared with corresponding tissues and liver cells. Overexpression of ADAM15 was linked to poor prognosis, and was an independent risk factor for HCC prognosis. Besides, analysis of immune infiltration indicated that ADAM15 expression was related to tumor infiltrating lymphocytes based on the TIMER, TISIDB and GEPIA databases. Many immune checkpoint gene expression was associated with ADAM15 expression. Functional enrichment analyses indicated that apoptosis, cell adhesion was enriched. ADAM15 knockdown promoted apoptosis and suppressed proliferation, migration and invasion of liver cancer cells. The findings of western blot showed that ADAM15 knockdown reduced the expression of Bcl-2, Vimentin, N-Cadherin and Snail, and elevated the expression of Bax, E-cadherin and ZO-1. However, overexpression of ADAM15 had the opposite results. Collectively, our findings demonstrated that ADAM15 was connected with poor prognosis of HCC patients, and could be considered as a potential biomarker for the diagnosis and treatment of HCC.

MCM5 Aggravates the HDAC1-Mediated Malignant Progression of Lung Cancer

Background

Histone deacetylase 1 (HDAC1) is essential in the malignant progression of tumors. However, there is no obvious relationship between the expression of HDAC1 and the survival of lung cancer patients. Herein, we explored the involvement of minichromosome maintenance complex component 5 (MCM5) and HDAC1 interaction in the epithelial-to-mesenchymal transition (EMT)-dependent malignant progression of lung cancer.

Methods

We analyzed the expression of MCM5 and HDAC1 in The Cancer Genome Atlas database and clinical samples, as well as their impact on patient survival. Cell and animal experiments were performed to verify the promotion of EMT in lung cancer cells mediated by MCM5 and HDAC1.

Results

We found that lung adenocarcinoma patients with high expression of MCM5 and HDAC1 had poor survival time. Overexpression of MCM5 and HDAC1 in A549 and H1975 cells can promote proliferation and invasion in vitro and tumor growth and metastasis in vivo. Moreover, astragaloside IV can block the interaction between HDAC1 and MCM5, which can then inhibit the malignant progression of lung cancer in vivo and in vitro.

Conclusion

The interaction between MCM5 and HDAC1 aggravated the EMT-dependent malignant progression of lung cancer. Astragaloside IV can block the interaction between MCM5 and HDAC1 to inhibit the progression of lung cancer.

The Expression of CLDN6 in Hepatocellular Carcinoma Tissue and the Effects of CLDN6 on Biological Phenotypes of Hepatocellular Carcinoma Cells

CLDN6, a member of claudin (CLDN) family, was found to be a breast cancer suppressor gene in our early experiments. However, CLDN6 was highly expressed in human hepatocellular carcinoma (hHCC) (TCGA database), and the role of CLDN6 in hHCC is still unclear. To investigate the expression of CLDN6, immunohistochemical staining was performed in hHCC tissues. As a result, hHCC tissues highly expressed CLDN6, and the expression was related to the degree of tumor's differentiation. To research the role of CLDN6 in hHCC cells, CLDN6 was silenced in HepG2 and Hep3B cells which highly expressed CLDN6 through liposome transfection. Results showed that after silencing of CLDN6, the proliferation, migration and invasion abilities of hHCC cells were inhibited. Meanwhile, the expression of E-cadherin was upregulated, and the expression of N-cadherin and Vimentin was downregulated. All the results above indicated that CLDN6 promoted the development of hHCC, and could be a potential target for the treatment of it.

Advances in deubiquitinating enzymes in lung adenocarcinoma

The process of ubiquitination and deubiquitination is widely present in the human body's protein reactions and plays versatile roles in multiple diseases. Deubiquitinating enzymes (DUBs) are significant regulators of this process, which cleave the ubiquitin (Ub) moiety from various substrates and maintain protein stability. Lung adenocarcinoma (LUAD) is the most common type of non-small cell lung cancer (NSCLC) and remains refractory to treatment. To elucidate the mechanism of LUAD and advance new therapeutic targets, we review the latest research progress on DUBs in LUAD. We summarize the biological capabilities of these DUBs and further highlight those DUBs that may serve as anticancer target candidates for precision treatment. We also discuss deubiquitinase inhibitors, which are expected to play a role in targeted LUAD therapy.

Nanotherapeutic approach to tackle chemotherapeutic resistance of cancer stem cells

Estimates indicate that cancer will become the leading cause of mortality worldwide in the future. Tumorigenesis is a complex process that involves self-sufficiency in signs of growth, insensitivity to anti-growth signals, prevention of apoptosis, unlimited replication, sustained angiogenesis, tissue invasion, and metastasis. Cancer stem cells (CSCs) have an important role in tumor development and resistance. Here we will approach phenotypic plasticity capacity, highly efficient DNA repair systems, anti-apoptotic machinery, sustained stemness features, interaction with the tumor microenvironment, and Notch, Wnt, and Hedgehog signaling pathways. The researches about CSCs as a target in cancer treatment has been growing. Many different options have pointed beneficial results, such as pathways and CSC-surface markers targeting. Besides its limitations, nanotherapeutics have emerged as a potential strategy in this context since they aim to improve pharmacokinetics, biodistribution, and reduce the side effects observed in traditional treatments. Nanoparticles have been studied in this field, mostly for drug delivery and a multitherapy approach. Another widely researched approaches in this area are related to heat therapy, such as photothermal therapy, photodynamic therapy and magnetic hyperthermia, besides molecular targeting. This review will contemplate the most relevant studies that have shown the effects of nanotherapeutics. In conclusion, although the studies analyzed are mostly preclinical, we believe that there is strong evidence that nanoparticles can increase the chances of a better prognosis to cancer in the future. It is also essential to transpose these findings to the clinic to confirm and better understand the role of nanotherapeutics in this context.

Methyltransferase like 13 mediates the translation of Snail in head and neck squamous cell carcinoma

Methyltransferase like 13 (METTL13), a kind of methyltransferase, is implicated in protein binding and synthesis. The upregulation of METTL13 has been reported in a variety of tumors. However, little was known about its potential function in head and neck squamous cell carcinoma (HNSCC) so far. In this study, we found that METTL13 was significantly upregulated in HNSCC at both mRNA and protein level. Increased METTL13 was negatively associated with clinical prognosis. And METTL13 markedly affected HNSCC cellular phenotypes in vivo and vitro. Further mechanism study revealed that METTL13 could regulate EMT signaling pathway by mediating enhancing translation efficiency of Snail, the key transcription factor in EMT, hence regulating the progression of EMT. Furthermore, Snail was verified to mediate METTL13-induced HNSCC cell malignant phenotypes. Altogether, our study had revealed the oncogenic role of METTL13 in HNSCC, and provided a potential therapeutic strategy.

Single-cell lineage tracing of metastatic cancer reveals selection of hybrid EMT states

The underpinnings of cancer metastasis remain poorly understood, in part due to a lack of tools for probing their emergence at high resolution. Here we present macsGESTALT, an inducible CRISPR-Cas9-based lineage recorder with highly efficient single-cell capture of both transcriptional and phylogenetic information. Applying macsGESTALT to a mouse model of metastatic pancreatic cancer, we recover ∼380,000 CRISPR target sites and reconstruct dissemination of ∼28,000 single cells across multiple metastatic sites. We find that cells occupy a continuum of epithelial-to-mesenchymal transition (EMT) states. Metastatic potential peaks in rare, late-hybrid EMT states, which are aggressively selected from a predominately epithelial ancestral pool. The gene signatures of these late-hybrid EMT states are predictive of reduced survival in both human pancreatic and lung cancer patients, highlighting their relevance to clinical disease progression. Finally, we observe evidence for in vivo propagation of S100 family gene expression across clonally distinct metastatic subpopulations.

Chemotherapy: a double-edged sword in cancer treatment

Chemotherapy is a well-known and effective treatment for different cancers; unfortunately, it has not been as efficient in the eradication of all cancer cells as been expected. The mechanism of this failure was not fully clarified, yet. Meanwhile, alterations in the physiologic conditions of the tumor microenvironment (TME) were suggested as one of the underlying possibilities. Chemotherapy drugs can activate multiple signaling pathways and augment the secretion of inflammatory mediators. Inflammation may show two opposite roles in the TME. On the one hand, inflammation, as an innate immune response, tries to suppress tumor growth but on the other hand, it might be not powerful enough to eradicate the cancer cells and even it can provide appropriate conditions for cancer promotion and relapse as well. Therefore, the administration of mild anti-inflammatory drugs during chemotherapy might result in more successful clinical results. Here, we will review and discuss this hypothesis. Most chemotherapy agents are triggers of inflammation in the tumor microenvironment through inducing the production of senescence-associated secretory phenotype (SASP) molecules. Some chemotherapy agents can induce systematic inflammation by provoking TLR4 signaling or triggering IL-1B secretion through the inflammasome pathway. NF-kB and MAPK are key signaling pathways of inflammation and could be activated by several chemotherapy drugs. Furthermore, inflammation can play a key role in cancer development, metastasis and exacerbation.

MAGE-C3 promotes cancer metastasis by inducing epithelial-mesenchymal transition and immunosuppression in esophageal squamous cell carcinoma

Background

Evading immune surveillance is necessary for tumor metastasis. Thus, there is an urgent need to better understand the interaction between metastasis and mechanisms of tumor immune evasion. In this study, we aimed to clarify a novel mechanism that link tumor metastasis and immunosuppression in the development of esophageal squamous cell carcinoma (ESCC).

Methods

The expression of melanoma‐associated antigen C3 (MAGE‐C3) was detected using immunohistochemistry. Transwell assays were used to evaluate the migration and invasion ability of esophageal squamous cell carcinoma (ESCC) cells. Metastasis assays in mice were used to evaluate metastatic ability in vivo. Lymphocyte‐mediated cytotoxicity assays were performed to visualize the immune suppression function on tumor cells. RNA sequencing was performed to identify differentially expressed genes between MAGE‐C3 overexpressing ESCC cells and control cells. Gene ontology (GO) enrichment analyses was performed to identify the most altered pathways influenced by MAGE‐C3. The activation of the interferon‐γ (IFN‐γ) pathway was analyzed using Western blotting, GAS luciferase reporter assays, immunofluorescence, and flow cytometry. The role of MAGE‐C3 in the IFN‐γ pathway was determined by Western blotting and immunoprecipitation. Furthermore, immunohistochemistry and flow cytometry analysis monitored the changes of infiltrated T cell populations in murine lung metastases.

Results

MAGE‐C3 was overexpressed in ESCC tissues. High expression of MAGE‐C3 had a significant association with the risk of lymphatic metastasis and poor survival in patients with ESCC. Functional experiments revealed that MAGE‐C3 promoted tumor metastasis by activating the epithelial‐mesenchymal transition (EMT). MAGE‐C3 repressed antitumor immunity and regulated cytokine secretion of T cells, implying an immunosuppressive function. Mechanistically, MAGE‐C3 facilitated IFN‐γ signaling and upregulated programmed cell death ligand 1 (PD­L1) by binding with IFN‐γ receptor 1 (IFNGR1) and strengthening the interaction between IFNGR1 and signal transducer and activator of transcription 1 (STAT1). Interestingly, MAGE‐C3 displayed higher tumorigenesis in immune‐competent mice than in immune‐deficient nude mice, confirming the immunosuppressive role of MAGE‐C3. Furthermore, mice bearing MAGE‐C3‐overexpressing tumors showed worse survival and more lung metastases with decreased CD8⁺ infiltrated T cells and increased programmed cell death 1 (PD‐1)⁺CD8⁺ infiltrated T cells.

Conclusion

MAGE‐C3 enhances tumor metastasis through promoting EMT and protecting tumors from immune surveillance, and could be a potential prognostic marker and therapeutic target.

Rapid Naked-Eye Tracking of On-Cell Phenotype Based on Dual-Aptamer-Weaved Cascade Assembly of Nanostructures

Phenotypic plasticity is an emerging paradigm for providing biological and clinical insights into cancer initiation, progression, and resistance to therapy. However, it is a great challenge to track phenotypic information on live cells with high levels of sensitivity, specificity, and simplicity, when a specific cancer-cell subset is being targeted. In this work, we have successfully achieved cascade assembly of nanoparticles on the surface of specific cancer cells by designing a dual-aptamer-weaved molecular AND logic system. Taking advantage of spatial addressability, precise controllability, and targeting recognition of the nanostructure assemblies, we can precisely label the target-cell subset in a large population of similar cells and rapidly obtain phenotypic information in response to the surface changes of captured cancer cells. Without sophisticated instruments, we can know the phenotypic information on HepG2 cells in whole blood with a high level of sensitivity and rapid naked-eye tracking of on-cell phenotype changes of HepG2 cells undergoing epithelial-mesenchymal transition.

FOXD1 promotes EMT and cell stemness of oral squamous cell carcinoma by transcriptional activation of SNAI2

Background

Epithelial-mesenchymal transition (EMT) and cell stemness are implicated in the initiation and progression of oral squamous cell carcinoma (OSCC). Revealing the intrinsic regulatory mechanism may provide effective therapeutic targets for OSCC.

Results

In this study, we found that Forkhead box D1 (FOXD1) was upregulated in OSCC compared with normal samples. Patients with a higher FOXD1 expression had a poorer overall survival and disease-free survival. Immunohistochemical staining results showed that FOXD1 expression was related to the clinical stage and relapse status of OSCC patients. When FOXD1 expression was knocked down in CAL27 and SCC25 cells, the migration, invasion, colony formation, sphere formation, and proliferation abilities decreased. Moreover, EMT and stemness-related markers changed remarkably, which indicated that the EMT process and cell stemness were inhibited. Conversely, overexpression of FOXD1 promoted EMT and cell stemness. Further study demonstrated that FOXD1 could bind to the promoter region and activate the transcription of SNAI2. In turn, the elevated SNAI2 affected EMT and cell stemness. An in vivo study showed that FOXD1-overexpressing CAL27 cells possessed a stronger tumorigenic ability.

Conclusions

Our findings revealed a novel mechanism in regulating EMT and cell stemness and proposed FOXD1 as a potential marker for the diagnosis and treatment of OSCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00671-9.

PTPL1 suppresses lung cancer cell migration via inhibiting TGF-β1-induced activation of p38 MAPK and Smad 2/3 pathways and EMT

Epithelial-mesenchymal transition (EMT) enables dissemination of neoplastic cells and onset of distal metastasis of primary tumors. However, the regulatory mechanisms of EMT by microenvironmental factors such as transforming growth factor-β (TGF-β) remain largely unresolved. Protein tyrosine phosphatase L1 (PTPL1) is a non-receptor protein tyrosine phosphatase that plays a suppressive role in tumorigenesis of diverse tissues. In this study we investigated the role of PTPL1/PTPN13 in metastasis of lung cancer and the signaling pathways regulated by PTPL1 in terms of EMT of non-small cell lung cancer (NSCLC) cells. We showed that the expression of PTPL1 was significantly downregulated in cancerous tissues of 23 patients with NSCLC compared with adjacent normal tissues. PTPL1 expression was positively correlated with overall survival of NSCLC patients. Then we treated A549 cells in vitro with TGF-β1 (10 ng/mL) and assessed EMT. We found that knockdown of PTPL1 enhanced the migration and invasion capabilities of A549 cells, through enhancing TGF-β1-induced EMT. In nude mice bearing A549 cell xenografts, knockdown of PTPL1 significantly promoted homing of cells and formation of tumor loci in the lungs. We further revealed that PTPL1 suppressed TGF-β-induced EMT by counteracting the activation of canonical Smad2/3 and non-canonical p38 MAPK signaling pathways. Using immunoprecipitation assay we demonstrated that PTPL1 could bind to p38 MAPK, suggesting that p38 MAPK might be a direct substrate of PTPL1. In conclusion, these results unravel novel mechanisms underlying the regulation of TGF-β signaling pathway, and have implications for prognostic assessment and targeted therapy of metastatic lung cancer.

Partial EMT in head and neck cancer biology: a spectrum instead of a switch

Our understanding of epithelial-to-mesenchymal transition (EMT) has slowly evolved from a simple two state, binary model to a multi-step, dynamic continuum of epithelial-to-mesenchymal plasticity, with metastable intermediate transition states that may drive cancer metastasis. Head and neck cancer is no exception, and in this review, we use head and neck as a case study for how partial-EMT (p-EMT) cell states may play an important role in cancer progression. In particular, we summarize recent in vitro and in vivo studies that uncover these intermediate transition states, which exhibit both epithelial and mesenchymal properties and appear to have distinct advantages in migration, survival in the bloodstream, and seeding and propagation within secondary metastatic sites. We then summarize the common and distinct regulators of p-EMT as well as methodologies for identifying this unique cellular subpopulation, with a specific emphasis on the role of cutting-edge technologies, such as single cell approaches. Finally, we propose strategies to target p-EMT cells, highlighting potential opportunities for therapeutic intervention to specifically target the process of metastasis. Thus, although significant challenges remain, including numerous gaps in current knowledge, a deeper understanding of EMT plasticity and a genuine identification of EMT as spectrum rather than a switch will be critical for improving patient diagnosis and treatment across oncology.

ETS1 promoted cell growth, metastasis and epithelial-mesenchymal transition process in melanoma by regulating miR-16-mediated SOX4 expression

Melanoma is a malignant tumor with high metastasis and mortality. Epithelial-mesenchymal transition (EMT) was reported to be involved in the growth and metastasis of melanoma. To investigate these sections further, we showed that E26 transformation specific 1 (ETS1) could regulate growth, metastasis and EMT process of melanoma by regulating microRNA(miR)-16/SRY-related HMG box (SOX) 4 expression. MiR-16, ETS1, SOX4 and nuclear factor κB (NF-κB) expression levels in melanoma cells were examined using qPCR. ETS1, SOX4, EMT-related proteins and NF-κB signaling pathway-related proteins were examined using western blot. Cell counting kit-8 assay, transwell assay were applied to evaluate the cell proliferation, migration and invasion of melanoma cells, respectively. Besides, a dual-luciferase reporter assay was employed to verify the binding relationship between ETS1 and miR-16, miR-16 and SOX4, miR-16 and NF-κB1. We showed that ETS1 and SOX4 were upregulated in melanoma cells, while miR-16 was downregulated. MiR-16 overexpression suppressed growth, metastasis and EMT process of melanoma. We found ETS1 could bind to the promoter region of miR-16 and inhibited its transcription. ETS1 silence could inhibit growth, metastasis and EMT process of melanoma, and inhibition of miR-16 could reverse the effects. Besides, miR-16 is directly bound to SOX4 and downregulated its expression. Rescued experiments confirmed that SOX4 overexpression abolished the inhibition effect of miR-16 mimics on growth, metastasis and EMT process of melanoma. Finally, NF-κB1 as the target of miR-16 mediated downstream biological responses. ETS1 activated NF-κB signaling pathway through miR-16 via targeting SOX4, thus promoting growth, metastasis and EMT of melanoma.

Immunofluorescence Image Feature Analysis and Phenotype Scoring Pipeline for Distinguishing Epithelial-Mesenchymal Transition

Epithelial–mesenchymal transition (EMT) is an essential biological process, also implicated in pathological settings such as cancer metastasis, in which epithelial cells transdifferentiate into mesenchymal cells. We devised an image analysis pipeline to distinguish between tissues comprised of epithelial and mesenchymal cells, based on extracted features from immunofluorescence images of differing biochemical markers. Mammary epithelial cells were cultured with 0 (control), 2, 4, or 10 ng/mL TGF-β1, a well-established EMT-inducer. Cells were fixed, stained, and imaged for E-cadherin, actin, fibronectin, and nuclei via immunofluorescence microscopy. Feature selection was performed on different combinations of individual cell markers using a Bag-of-Features extraction. Control and high-dose images comprised the training data set, and the intermediate dose images comprised the testing data set. A feature distance analysis was performed to quantify differences between the treatment groups. The pipeline was successful in distinguishing between control (epithelial) and the high-dose (mesenchymal) groups, as well as demonstrating progress along the EMT process in the intermediate dose groups. Validation using quantitative PCR (qPCR) demonstrated that biomarker expression measurements were well-correlated with the feature distance analysis. Overall, we identified image pipeline characteristics for feature extraction and quantification of immunofluorescence images to distinguish progression of EMT.

Collective metastasis: coordinating the multicellular voyage

The metastatic process is arduous. Cancer cells must escape the confines of the primary tumor, make their way into and travel through the circulation, then survive and proliferate in unfavorable microenvironments. A key question is how cancer cells overcome these multiple barriers to orchestrate distant organ colonization. Accumulating evidence in human patients and animal models supports the hypothesis that clusters of tumor cells can complete the entire metastatic journey in a process referred to as collective metastasis. Here we highlight recent studies unraveling how multicellular coordination, via both physical and biochemical coupling of cells, induces cooperative properties advantageous for the completion of metastasis. We discuss conceptual challenges and unique mechanisms arising from collective dissemination that are distinct from single cell-based metastasis. Finally, we consider how the dissection of molecular transitions regulating collective metastasis could offer potential insight into cancer therapy.

Genomic and transcriptomic profiling of hepatoid adenocarcinoma of the stomach

Hepatoid adenocarcinoma of the stomach (HAS), a rare subtype of gastric cancer (GC), has a low incidence but a high mortality rate. Little is known about the molecular features of HAS. Here we applied whole-exome sequencing (WES) on 58 tumours and the matched normal controls from 54 HAS patients, transcriptome sequencing on 30 HAS tumours, and single-cell RNA sequencing (scRNA-seq) on one HAS tumour. Our results reveal that the adenocarcinomatous component and hepatocellular-like component of the same HAS tumour originate monoclonally, and HAS is likely to initiate from pluripotent precursor cells. HAS has high stemness and high methionine cycle activity compared to classical GC. Two genes in the methionine cycle, MAT2A, and AHCY are potential targets for HAS treatments. We provide the first integrative genomic profiles of HAS, which may facilitate its diagnosis, prognosis, and treatment.

Expression and prognostic potential of PLEK2 in head and neck squamous cell carcinoma based on bioinformatics analysis

Background

PLEK2 (pleckstrin) could bind to membrane‐bound phosphatidylinositols and further promote cell spread. Recently, several studies have noted the importance of PLEK2 in tumor metastasis. However, the role of PLEK2 in head and neck squamous cell carcinoma (HNSCC) remains to be elucidated.

Methods

The PLEK2 expression in HNSCC was identified using Oncomine, Gene Expression Omnibus (GEO), UALCAN databases, and western blot analysis. Prognosis analysis was performed using Kaplan–Meier plotter, DriverDBv3, UALCAN, UCSC Xena, and GEO databases. Single‐cell functional analysis was further performed using the cancerSEA database. The PLEK2‐related co‑expressed genes were identified, and gene set enrichment analysis was performed using LinkedOmics. Furthermore, the top 10 hub genes were identified using the cytoHubba plug‐in of Cytoscape. Then, gene enrichment analysis, pathway activity, and drug sensitivity analyses of the hub genes were performed using the R package “clusterProfiler” and GSCAlite. Finally, the UCSC Xena browser was utilized to explore the hub gene most likely to play a synergic role with PLEK2 in HNSCC.

Results

Elevated expression of PLEK2 was observed in HNSCC and even in HNSCC subgroups based on diverse clinicopathological features, portending a poor prognosis in HNSCC. PLEK2 was correlated with metastasis and hypoxia in HNSCC, and the PLEK2‐related co‐expressed genes were mainly involved in the focal adhesion pathway. The top 10 hub genes were primarily enriched in focal adhesion, HPV infection, ECM‐receptor interaction, and PI3K‐AKT signaling pathway, and epithelial–mesenchymal transition pathway was activated. Furthermore, the expression levels of the hub genes were associated with sensitivity and resistance to various small molecules and anti‐cancer drugs. Further study suggested that ITGA3 and PLEK2 might be viewed as inextricably linked in facilitating HNSCC metastasis.

Conclusions

In general, PLEK2 might serve as a potential biomarker for the diagnosis of HNSCC and guide the development of targeted therapies for HNSCC.

Transcription factor POU4F2 promotes colorectal cancer cell migration and invasion through hedgehog-mediated epithelial-mesenchymal transition

As a POU homeodomain transcription factor, POU4F2 has been implicated in regulating tumorigenic processes in various cancers. However, the role of POU4F2 in colorectal cancer (CRC) remains unclear. Here, we revealed that POU4F2 functions as a tumor promotor in CRC. Bioinformatics analysis in specimens from CRC patients and expression analysis in CRC cell lines showed that POU4F2 was upregulated at the mRNA and protein levels in CRC. Depletion of POU4F2 suppressed the metastatic phenotypes of CRC cells, including cell migration, invasion, and the expression of epithelial‐mesenchymal transition (EMT) markers. Moreover, depletion of POU4F2 decreased the number of lung metastatic nodes in nude mice. Mechanistically, POU4F2 positively regulated the Hedgehog signaling pathway, as inferred from the downregulation of the expression of sonic Hedgehog homolog, patched 1, Smoothened, and GLI family zinc finger 1 in vitro and vivo following silencing of POU4F2. Furthermore, the SMO agonist SAG reversed the effects of POU4F2 knockdown in CRC. Functionally, POU4F2 contributed to the Hedgehog signaling‐regulated activation of the EMT process and promotion of CRC cell migration and invasion. Collectively, these findings elucidated the role of POU4F2 as a tumor promotor in CRC through the regulation of Hedgehog signaling‐mediated EMT and suggested that POU4F2 suppression might be a promising therapeutic target in inhibiting CRC metastasis.

Cisplatin Plus Cetuximab Inhibits Cisplatin-Resistant Human Oral Squamous Cell Carcinoma Cell Migration and Proliferation but Does Not Enhance Apoptosis

Cisplatin is among the most widely used anticancer drugs used in the treatment of several malignancies, including oral cancer. However, cisplatin treatment often promotes chemical resistance, subsequently causing treatment failure. Several studies have shown that epidermal growth factor receptors (EGFRs) play a variety of roles in cancer progression and overcoming cisplatin resistance. Therefore, this study focused on EGFR inhibitors used in novel targeted therapies as a method to overcome this resistance. We herein aimed to determine whether the combined effects of cisplatin and cetuximab could enhance cisplatin sensitivity by inhibiting the epithelial-to-mesenchymal transition (EMT) process in cisplatin-resistant cells. In vitro analyses of three cisplatin-resistant oral squamous cell carcinoma cells, which included cell proliferation assay, combination index calculation, cell cytotoxicity assay, live/dead cell count assay, Western blot assay, propidium iodide staining assay, scratch assay, and qRT-PCR assay were then conducted. Our results showed that a cisplatin/cetuximab combination treatment inhibited cell proliferation, cell motility, and N-cadherin protein expression but induced E-cadherin and claudin-1 protein expression. Although the combination of cisplatin and cetuximab did not induce apoptosis of cisplatin-resistant cells, it may be useful in treating oral cancer patients with cisplatin resistance given that it controls cell motility and EMT-related proteins.

Epithelial to Mesenchymal Transition in Patients with Pancreatic Ductal Adenocarcinoma: State-of-the-Art and Therapeutic Opportunities

Pancreatic ductal adenocarcinoma (PDAC) is one of the malignancies with the worst prognosis despite a decade of efforts. Up to eighty percent of patients are managed at late stages with metastatic disease, in part due to a lack of diagnosis. The effectiveness of PDAC therapies is challenged by the early and widespread metastasis. Epithelial to mesenchymal transition (EMT) is a major driver of cancer progression and metastasis. This process allows cancer cells to gain invasive properties by switching their phenotype from epithelial to mesenchymal. The importance of EMT has been largely described in PDAC, and its importance is notably highlighted by the two major subtypes found in PDAC: the classical epithelial and the quasi-mesenchymal subtypes. Quasi-mesenchymal subtypes have been associated with a poorer prognosis. EMT has also been associated with resistance to treatments such as chemotherapy and immunotherapy. EMT is associated with several key molecular markers both epithelial and mesenchymal. Those markers might be helpful as a biomarker in PDAC diagnosis. EMT might becoming a key new target of interest for the treatment PDAC. In this review, we describe the role of EMT in PDAC, its contribution in diagnosis, in the orientation and treatment follow-up. We also discuss the putative role of EMT as a new therapeutic target in the management of PDAC.

Grape Seed Proanthocyanidins Inhibit Migration and Invasion of Bladder Cancer Cells by Reversing EMT through Suppression of TGF-β Signaling Pathway

Bladder cancer (BC) is the most common cancer of the urinary system. Despite advances in diagnosis and therapy, the prognosis is still poor because of recurrence and metastasis. Epithelial-mesenchymal transition (EMT) is considered to play an important role in the invasion and metastasis of BC. Grape seed proanthocyanidins (GSPs) exhibit chemopreventive and chemotherapeutic activities against several types of cancer. However, their effects and underlying mechanisms on the invasive potential of BC remain unclear. In this study, we found that GSPs inhibited migration, invasion, and MMP-2/-9 secretion of both T24 and 5637 bladder cancer cells at noncytotoxic concentrations. We also discovered that 5637 cells were more suitable than T24 cells for the EMT study. Further study showed that GSPs inhibited EMT by reversing the TGF-β-induced morphological change and upregulation of mesenchymal markers N-cadherin, vimentin, and Slug as well as downregulation of epithelial markers E-cadherin and ZO-1 in 5637 cells. GSPs also inhibited TGF-β-induced phosphorylation of Smad2/3, Akt, Erk, and p38 in 5637 cells without affecting the expression of total Smad2/3, Akt, Erk, and p38. Taken together, the results of the present study demonstrate that GSPs effectively inhibit the migration and invasion of BC cells by reversing EMT through suppression of the TGF-β signaling pathway, which indicates that GSPs could be developed as a potential chemopreventive and therapeutic agent against bladder cancer.

Exosomal miR-125b Exerts Anti-Metastatic Properties and Predicts Early Metastasis of Hepatocellular Carcinoma

BACKGROUND & AIMS

Cancer metastasis is responsible for the majority of cancer-related deaths. Exosomal miRNAs have emerged as promising biomarkers for cancer, serving as signaling molecules that can regulate tumor growth and metastasis. This study examined circulating exosomal miRNAs that could predict hepatocellular carcinoma (HCC) metastasis.

METHODS

Exosomal miRNA was measured by quantitative real-time PCR (qRT-PCR) in a large set of patients (n = 284). To investigate the role of exosomal miRNA in HCC, we performed a series of in vitro tests, such as exosome labeling, qRT-PCR, reverse transcription PCR, wound healing assay, transwell assay, and Western blot assay.

RESULTS

Exosomal miR-125b was drastically downregulated in HCC patients with metastasis than in those without metastasis. In vitro, we observed the uptake of miR-125b by exosome in recipient cells. Exosome-mediated miR-125b significantly inhibited migration and invasion abilities and downregulated the mRNA expressions of MMP-2, MMP-9, and MMP-14 in recipient cells via intercellular communication. Further investigation revealed that miR-125b suppressed SMAD2 protein expression in recipient cells by binding to its 3' untranslated regions. Exosome-mediated miR-125b transfer also disrupted TGF-β1-induced epithelial-mesenchymal transition and TGF-β1/SMAD signaling pathway in recipient cells by leading to a decrease of SMAD2 protein expression. Moreover, exosomal miR-125b was downregulated after metastasis compared with that at baseline in patients with serial measurements before and after metastasis.

CONCLUSIONS

The results imply that exosome-mediated miR-125b exerts anti-metastatic properties in HCC. These findings highlight that circulating exosomal miR-125b might represent a reliable biomarker with diagnostic and therapeutic implications for extrahepatic metastasis from HCC.

A Novel Six Metastasis-Related Prognostic Gene Signature for Patients With Osteosarcoma

Osteosarcoma is the most common malignant bone tumor, and although there has been significant progress in its management, metastases often herald incurable disease. Here we defined genes differentially expressed between primary and metastatic osteosarcoma as metastasis-related genes (MRGs) and used them to construct a novel six-MRG prognostic signature for overall survival of patients with osteosarcoma. Validation in internal and external datasets confirmed satisfactory accuracy and generalizability of the prognostic model, and a nomogram based on the signature and clinical variables was constructed to aid clinical decision-making. Of the six MRGs, FHIT is a well-documented tumor suppressor gene that is poorly defined in osteosarcoma. Consistent with tumor suppressor function, FHIT was downregulated in osteosarcoma cells and human osteosarcoma samples. FHIT overexpression inhibited osteosarcoma proliferation, migration, and invasion both in vitro and in vivo. Mechanistically, FHIT overexpression upregulate the epithelial marker E-cadherin while repressing the mesenchymal markers N-cadherin and vimentin. Our six-MRG signature represents a novel and clinically useful prognostic biomarker for patients with osteosarcoma, and FHIT might represent a therapeutic target by reversing epithelial to mesenchymal transition.

The Role of TGF-β Signaling Pathways in Cancer and Its Potential as a Therapeutic Target

The transforming growth factor-β (TGF-β) signaling pathway mediates various biological functions, and its dysregulation is closely related to the occurrence of malignant tumors. However, the role of TGF-β signaling in tumorigenesis and development is complex and contradictory. On the one hand, TGF-β signaling can exert antitumor effects by inhibiting proliferation or inducing apoptosis of cancer cells. On the other hand, TGF-β signaling may mediate oncogene effects by promoting metastasis, angiogenesis, and immune escape. This review summarizes the recent findings on molecular mechanisms of TGF-β signaling. Specifically, this review evaluates TGF-β's therapeutic potential as a target by the following perspectives: ligands, receptors, and downstream signaling. We hope this review can trigger new ideas to improve the current clinical strategies to treat tumors related to the TGF-β signaling pathway.

Circular RNA circSETD3 hampers cell growth, migration, and stem cell properties in bladder cancer through sponging miR-641 to upregulate PTEN

Bladder cancer (BLCA) is a common malignant urothelial cancer in the world. Although circular RNAs (circRNAs) involve in regulating BLCA progression, the role of a novel circular RNA circSETD3 in regulating BLCA pathogenesis has not been studied. The expression of circSETD3, miR-641, PTEN mRNA in BLCA tissues and cell lines were measured using RT-qPCR. The gain-of-function experiments were performed in vitro and in vivo to detect the effects of circSETD3 on cell proliferation, migration, EMT, and stemness maintenance. Besides, rescue experiments were performed to demonstrate the regulatory mechanism of circSETD3/miR-641/PTEN in BLCA cell malignant phenotypes in vitro. CircSETD3 was remarkably downregulated in the cancerous clinical tissues and cell lines, in contrast with their normal counterparts, and circSETD3 tended to be deficient in BLCA patients with larger tumor size, advanced clinical stages, positive lymph metastasis and worse prognosis. In addition, circular isoforms of circSETD3 were more resistant to RNase R+ and actinomycetes D treatment compared to their linear isoforms, and circSETD3 mainly distributed in the cytoplasm of the BLCA cells. Further gain-of-function experiments showed that circSETD3 acted as a tumor suppressor to suppress BLCA cell proliferation, migration, EMT and stemness, and the underlying mechanisms had also been elucidated. Mechanistically, circSETD3 sponged miR-641 to upregulate PTEN, resulting in the blockage of BLCA progression. Our findings indicated that circSETD3 acted as a vital tumor suppressor in BLCA via regulating the miR-641/PTEN axis.

Breast cancer as an example of tumour heterogeneity and tumour cell plasticity during malignant progression

Heterogeneity within a tumour increases its ability to adapt to constantly changing constraints, but adversely affects a patient's prognosis, therapy response and clinical outcome. Intratumoural heterogeneity results from a combination of extrinsic factors from the tumour microenvironment and intrinsic parameters from the cancer cells themselves, including their genetic, epigenetic and transcriptomic traits, their ability to proliferate, migrate and invade, and their stemness and plasticity attributes. Cell plasticity constitutes the ability of cancer cells to rapidly reprogramme their gene expression repertoire, to change their behaviour and identities, and to adapt to microenvironmental cues. These features also directly contribute to tumour heterogeneity and are critical for malignant tumour progression. In this article, we use breast cancer as an example of the origins of tumour heterogeneity (in particular, the mutational spectrum and clonal evolution of progressing tumours) and of tumour cell plasticity (in particular, that shown by tumour cells undergoing epithelial-to-mesenchymal transition), as well as considering interclonal cooperativity and cell plasticity as sources of cancer cell heterogeneity. We review current knowledge on the functional contribution of cell plasticity and tumour heterogeneity to malignant tumour progression, metastasis formation and therapy resistance.

TRIM16 overexpression inhibits the metastasis of colorectal cancer through mediating Snail degradation

Tripartite motif containing 16 (TRIM16) is a member of the tripartite motif protein family and functions as a potential tumor suppressor in several cancers. However, the specific function and clinical significance of TRIM16 in colorectal cancer (CRC) remains unclear. In this study, we observed that low TRIM16 expression was detected frequently in primary colorectal cancer (CRC) tissues and was closely associated with a better prognosis. Functional studies demonstrate that TRIM16 overexpression notably inhibits the metastasis abilities of CRC in vivo and in vitro. Mechanistically, our results demonstrated that TRIM16 directly bound and ubiquitinated Snail family transcriptional repressor 1 (Snail), an important transcriptional factor of the epithelial-mesenchymal transition (EMT) process suppressing the EMT in CRC. Additionally, our data revealed that the inhibition effect of TRIM16 on cancer metastasis was dependent on Snail degradation. Collectively, our study is the first to report that TRIM16 plays a crucial anti-tumor role in CRC tumorigenesis. We also provided novel evidence that TRIM16 might act as a prognostic and therapeutic target to assess and inhibit CRC progression.

Partial EMT in Squamous Cell Carcinoma: A Snapshot

In the process of cancer EMT, some subgroups of cancer cells simultaneously exhibit both mesenchymal and epithelial characteristics, a phenomenon termed partial EMT (pEMT). pEMT is a plastic state in which cells coexpress epithelial and mesenchymal markers. In squamous cell carcinoma (SCC), pEMT is regulated, and the phenotype is maintained via the HIPPO pathway, NOTCH pathway and TGF-β pathways and by microRNAs, lncRNAs and the cancer microenvironment (CME); thus, SCC exhibits aggressive tumorigenic properties and high stemness, which leads collective migration and therapy resistance. Few studies have reported therapeutic interventions to address cells that have undergone pEMT, and this approach may be an effective way to inhibit the plasticity, drug resistance and metastatic potential of SCC.

Metabolic control of cancer progression as novel targets for therapy

Metabolism is an important part of tumorigenesis as well as progression. The various cancer metabolism pathways, such as glucose metabolism and glutamine metabolism, directly regulate the development and progression of cancer. The pathways by which the cancer cells rewire their metabolism according to their needs, surrounding environment and host tissue conditions are an important area of study. The regulation of these metabolic pathways is determined by various oncogenes, tumor suppressor genes, as well as various constituent cells of the tumor microenvironment. Expanded studies on metabolism will help identify efficient biomarkers for diagnosis and strategies for therapeutic interventions and countering ways by which cancers may acquire resistance to therapy.

Molecular mechanism involved in epithelial to mesenchymal transition

Epithelial to mesenchymal transition (EMT) is a biological process that plays an important role during embryonic development. During this process, the epithelial cells lose their polarity and acquire mesenchymal properties. In addition to embryonic development, EMT is also well-known to participate in tissue repair, inflammation, fibrosis, and tumor metastasis. In the present review, we address the basics of epithelial to mesenchymal transition during both development and disease conditions and emphasize the role of various transcription factors and miRNAs involved in the process.

The significance of exosomal RNAs in the development, diagnosis, and treatment of pancreatic cancer

Exosomes are single-membrane, secreted organelles with a diameter of 30–200 nm, containing diverse bioactive constituents, including DNAs, RNAs, proteins, and lipids, with prominent molecular heterogeneity. Extensive studies indicate that exosomal RNAs (e.g., microRNAs, long non-coding RNAs, and circular RNAs) can interact with many types of cancers, associated with several hallmark features like tumor growth, metastasis, and resistance to therapy. Pancreatic cancer (PaCa) is among the most lethal cancers worldwide, emerging as the seventh foremost cause of cancer-related death in both sexes. Hence, revealing the specific pathogenesis and improving the clinical diagnosis and treatment process are urgently required. As the study of exosomes has become an active area of research, the functional connections between exosomes and PaCa have been deeply investigated. Among these, exosomal RNAs seem to play a significant role in the development, diagnosis, and treatment of PaCa. Exosomal RNAs delivery ultimately modulates the various features of PaCa, and many scholars have interpreted how exosomal RNAs contribute to the proliferation, angiogenesis, migration, invasion, metastasis, immune escape, and drug resistance in PaCa. Besides, recent studies emphasize that exosomal RNAs may serve as diagnostic and prognostic biomarkers or therapeutic targets for PaCa. In this review, we will introduce these recent insights focusing on the discoveries of the relationship between exosomal RNAs and PaCa, and the potentially diagnostic and therapeutic applications of exosomes in PaCa.

Suppressive Effect and Molecular Mechanism of Houttuynia cordata Thunb. Extract against Prostate Carcinogenesis and Castration-Resistant Prostate Cancer

Simple Summary

This study explored the chemopreventive effects of Houttuynia cordata Thunb. (HCT) extracts against prostate carcinogenesis in both androgen-sensitive prostate cancer and castration-resistant prostate cancer (CRPC) using the Transgenic Rat for Adenocarcinoma of Prostate (TRAP) model, CRPC xenograft mice, and prostate cancer cell lines. HCT suppressed cell proliferation and stimulated apoptosis via inactivation of AKT/ERK/MAPK in both androgen-sensitive prostate cancer and CRPC cell lines. HCT also inhibited cell migration and EMT phenotypes through the STAT3/Snail/Twist pathway. One of the active compounds of HCT was identified as rutin. Consistent with in vitro study, the incidence of adenocarcinoma in the TRAP model and CRPC tumor growth in the xenograft model were suppressed by induction of apoptosis and inactivation of AKT/ERK/MAPK by HCT intake. Our data demonstrated that HCT attenuated androgen-sensitive prostate cancer and CRPC by mechanisms that may involve inhibition of cell growth and caspase-dependent apoptosis pathways.

Abstract

Houttuynia cordata Thunb. (HCT) is a well-known Asian medicinal plant with biological activities used in the treatment of many diseases including cancer. This study investigated the effects of HCT extract and its ethyl acetate fraction (EA) on prostate carcinogenesis and castration-resistant prostate cancer (CRPC). HCT and EA induced apoptosis in androgen-sensitive prostate cancer cells (LNCaP) and CRPC cells (PCai1) through activation of caspases, down-regulation of androgen receptor, and inactivation of AKT/ERK/MAPK signaling. Rutin was found to be a major component in HCT (44.00 ± 5.61 mg/g) and EA (81.34 ± 5.21 mg/g) in a previous study. Rutin had similar effects to HCT/EA on LNCaP cells and was considered to be one of the active compounds. Moreover, HCT/EA inhibited cell migration and epithelial-mesenchymal transition phenotypes via STAT3/Snail/Twist pathways in LNCaP cells. The consumption of 1% HCT-mixed diet significantly decreased the incidence of adenocarcinoma in the lateral prostate lobe of the Transgenic rat for adenocarcinoma of prostate model. Similarly, tumor growth of PCai1 xenografts was significantly suppressed by 1% HCT treatment. HCT also induced caspase-dependent apoptosis via AKT inactivation in both in vivo models. Together, the results of in vitro and in vivo studies indicate that HCT has inhibitory effects against prostate carcinogenesis and CRPC. This plant therefore should receive more attention as a source for the future development of non-toxic chemopreventive agents against various cancers.

KRT18 Modulates Alternative Splicing of Genes Involved in Proliferation and Apoptosis Processes in Both Gastric Cancer Cells and Clinical Samples

Keratin 18 (KRT18), one of the most abundant keratins in epithelial and endothelial cells, has been reported to be aberrantly expressed in many malignancies and extensively regarded as a biomarker and important regulator in multiple cancers, including gastric cancer (GC). But the molecular regulatory mechanisms of KRT18 in GC patients and cells are largely unknown. In the present study, we analyzed the expression level of KRT18 in 450 stomach adenocarcinoma tissue samples from TCGA database and found a significantly higher expression level in tumor tissues. We then explored the potential functions of KRT18 in AGS cells (human gastric adenocarcinoma cell line) by KRT18 knockdown using siRNA and whole transcriptome RNA-seq analysis. Notably, KRT18 selectively regulates expression of cell proliferation and apoptotic genes. Beyond this, KRT18 affects the alternative splicing of genes enriched in apoptosis, cell cycle, and other cancer-related pathways, which were then validated by reverse transcription-quantitative polymerase chain reaction approach. We validated KRT18-KD promoted apoptosis and inhibited proliferation in AGS cells. We then used RNA-seq data of GC samples to further demonstrate the modulation of KRT18 on alternative splicing regulation. These results together support the conclusion that KRT18 extensively modulates diverse alternative splicing events of genes enriched in proliferation and apoptosis processes. And the dysregulated splicing factors at transcriptional or posttranscriptional level by KRT18 may contribute to the alternative splicing change of many genes, which expands the functional importance of keratins in apoptotic and cell cycle pathways at the posttranscriptional level in GC.

Regulatory roles of osteopontin in human lung cancer cell epithelial-to-mesenchymal transitions and responses

BACKGROUND

Lung cancer is still the main cause of death in patients with cancer, due to poor understanding of intracellular regulations. Of those, osteopontin (OPN) may induce the epithelial-to-mesenchymal transition (EMT) to promote tumor cell metastasis. The present study aims to evaluate the regulatory mechanism of internal and external OPN in the development of lung cancer.

METHODS

We evaluated genetic variations and different bioinformatics of genes in chromosome 4 among subtypes of lung cancer using global databases. We validated the expression of OPN and EMT-related proteins (e.g., E-cadherin, vimentin) in 208 non-small-cell lung cancer (NSCLC) tumors and the adjacent nontumorous tissues, further to explore the function of OPN in the progression of lung cancer, with a focus on a potential communication between OPN and EMT in the lung cancer.

RESULTS

We found that OPN might act as a target molecule in lung cancer, which is associated with lymph node metastasis, postresection recurrence/metastasis, and prognosis of patients with lung cancer. Biological behaviors and pathological responses of OPN varied among diseases, challenges, and severities. Overexpression of OPN was correlated with the existence of EMT in lung cancer tissues. Internal and external OPN plays the decisive roles in lung cancer cell movement, proliferation, and EMT formation, through the upregulation of OPN-PI3K and OPN-MEK pathways. PI3K and MEK inhibitors downregulated the process of EMT and biological behaviors of lung cancer cells, probably through altering vimentin-associated cytoskeletons.

CONCLUSION

OPN can be a metastasis-associated or specific biomarker for lung cancer and a potential target for antimetastatic treatment.

Machine learning reveals mesenchymal breast carcinoma cell adaptation in response to matrix stiffness

Epithelial-mesenchymal transition (EMT) and its reverse process, mesenchymal-epithelial transition (MET), are believed to play key roles in facilitating the metastatic cascade. Metastatic lesions often exhibit a similar epithelial-like state to that of the primary tumour, in particular, by forming carcinoma cell clusters via E-cadherin-mediated junctional complexes. However, the factors enabling mesenchymal-like micrometastatic cells to resume growth and reacquire an epithelial phenotype in the target organ microenvironment remain elusive. In this study, we developed a workflow using image-based cell profiling and machine learning to examine morphological, contextual and molecular states of individual breast carcinoma cells (MDA-MB-231). MDA-MB-231 heterogeneous response to the host organ microenvironment was modelled by substrates with controllable stiffness varying from 0.2kPa (soft tissues) to 64kPa (bone tissues). We identified 3 distinct morphological cell types (morphs) varying from compact round-shaped to flattened irregular-shaped cells with lamellipodia, predominantly populating 2-kPa and >16kPa substrates, respectively. These observations were accompanied by significant changes in E-cadherin and vimentin expression. Furthermore, we demonstrate that the bone-mimicking substrate (64kPa) induced multicellular cluster formation accompanied by E-cadherin cell surface localisation. MDA-MB-231 cells responded to different substrate stiffness by morphological adaptation, changes in proliferation rate and cytoskeleton markers, and cluster formation on bone-mimicking substrate. Our results suggest that the stiffest microenvironment can induce MET.