BIX02189 inhibits TGF-β1-induced lung cancer cell metastasis by directly targeting TGF-β type I receptor

Riboflavin protects against pancreatic cancer metastasis by targeting TGF-β receptor 1

The inhibition of transforming growth factor-β1 (TGF-β1) signaling by targeting TGF-β receptor 1 (TβR1) has been considered as an ideal approach for the prevention of pancreatic cancer metastasis. Utilizing a pharmacophore model for TβR1 inhibitors, candidate compounds with the potential TβR1 binding ability were screened from the U.S. Food and Drug Administration (FDA) database, and riboflavin (RF) with a highest fit value was chosen to investigate its binding ability to TβR1 and effect on TGF-β1 signaling in pancreatic cancer cells. Molecular docking and cellular thermal shift assay (CETSA) proved that RF at pharmacological concentrations could directly bind to TβR1. Further studies showed that pharmacological concentrations of RF in vitro could block TGF-β1 signaling, suppress the migration and invasion, and prevent epithelial-mesenchymal transition (EMT) process of pancreatic cancer cells in the absence or presence of TGF-β1 stimulation, indicating that RF presented anti-metastatic effect in pancreatic cancer cells. Knockdown of TβR1 could significantly attenuate the effects of RF on the migration and EMT process in pancreatic cancer cells, further confirming that the anti-metastatic effect of RF was achieved by blocking TGF-β1 signaling after binding to TβR1. Moreover, in a mouse model of pancreatic cancer metastasis, it was certified that RF administration could block lung and liver metastases, TGF-β1 signaling and EMT process of pancreatic cancer in vivo. In summary, our findings showed that RF could block TGF-β1 signaling by directly binding to TβR1, thereby suppressing the metastasis of pancreatic cancer cells by inhibiting EMT process both in vitro and in vivo.

Suppression of JAK2/STAT3 Pathway by Notoginsenoside R1 Reduces Epithelial-Mesenchymal Transition in Non-small Cell Lung Cancer

It has bene reported that a novel saponin-notoginsenoside R1 (NGR1) possesses strong anti-tumor activities. This study aimed to investigate the role and mechanism of NGR1 in non-small cell lung cancer (NSCLC). NSCLC cell viability, proliferation, migration, and invasiveness were assessed using the ex vivo assays. NSCLC xenograft mouse models were constructed to confirm the role of NGR1 in vivo. Epithelial-mesenchymal transition (EMT)-related proteins and key markers in the JAK2/STAT3 pathway were examined using immunoblotting and immunohistochemistry analyses. NGR1 treatment suppressed NSCLC cell growth ex vivo and in vivo. It also decreased the migratory and invasive capacities of NSCLC cells. Additionally, NGR1 increased E-cadherin expression and reduced N-cadherin, vimentin, and snail expression in TGF-β1-treated NSCLC cells and xenograft tumors. JAK2/STAT3 pathway was inhibited by NGR1. Moreover, a specific inhibitor of JAK2, AG490, or STAT3 silencing significantly enhanced the effects of NGR1 against the EMT process in NSCLC cells. NGR1 restrains EMT process in NSCLC by inactivating JAK2/STAT3 signaling, suggesting the potential of NGR1 in anti-NSCLC therapy.

GINS2 regulates temozolomide chemosensitivity via the EGR1/ECT2 axis in gliomas

Temozolomide (TMZ), a DNA alkylating agent, has become the primary treatment for glioma, the most common malignancy of the central nervous system. Although TMZ-containing regimens produce significant clinical response rates, some patients inevitably suffer from inferior treatment outcomes or disease relapse, likely because of poor chemosensitivity of glioma cells due to a robust DNA damage response (DDR). GINS2, a subunit of DNA helicase, contributes to maintaining genomic stability and is highly expressed in various cancers, promoting their development. Here, we report that GINS2 was upregulated in TMZ-treated glioma cells and co-localized with γH2AX, indicating its participation in TMZ-induced DDR. Furthermore, GINS2 regulated the malignant phenotype and TMZ sensitivity of glioma cells, mostly by promoting DNA damage repair by affecting the mRNA stability of early growth response factor 1 (EGR1), which in turn regulates the transcription of epithelial cell-transforming sequence 2 (ECT2). We constructed a GINS2-EGR1-ECT2 prognostic model, which accurately predicted patient survival. Further, we screened Palbociclib/BIX-02189 which dampens GINS2 expression and synergistically inhibits glioma cell proliferation with TMZ. These findings delineate a novel mechanism by which GINS2 regulates the TMZ sensitivity of glioma cells and propose a promising combination therapy to treat glioma.

Molecular and cellular evidence for the impact of a hypertrophic cardiomyopathy-associated RAF1 variant on the structure and function of contractile machinery in bioartificial cardiac tissues

Noonan syndrome (NS), the most common among RASopathies, is caused by germline variants in genes encoding components of the RAS-MAPK pathway. Distinct variants, including the recurrent Ser257Leu substitution in RAF1, are associated with severe hypertrophic cardiomyopathy (HCM). Here, we investigated the elusive mechanistic link between NS-associated RAF1S257L and HCM using three-dimensional cardiac bodies and bioartificial cardiac tissues generated from patient-derived induced pluripotent stem cells (iPSCs) harboring the pathogenic RAF1 c.770 C > T missense change. We characterize the molecular, structural, and functional consequences of aberrant RAF1-associated signaling on the cardiac models. Ultrastructural assessment of the sarcomere revealed a shortening of the I-bands along the Z disc area in both iPSC-derived RAF1S257L cardiomyocytes and myocardial tissue biopsies. The aforementioned changes correlated with the isoform shift of titin from a longer (N2BA) to a shorter isoform (N2B) that also affected the active force generation and contractile tensions. The genotype-phenotype correlation was confirmed using cardiomyocyte progeny of an isogenic gene-corrected RAF1S257L-iPSC line and was mainly reversed by MEK inhibition. Collectively, our findings uncovered a direct link between a RASopathy gene variant and the abnormal sarcomere structure resulting in a cardiac dysfunction that remarkably recapitulates the human disease.

Targeted nanomedicines remodeling immunosuppressive tumor microenvironment for enhanced cancer immunotherapy

Cancer immunotherapy has significantly flourished and revolutionized the limited conventional tumor therapies, on account of its good safety and long-term memory ability. Discouragingly, low patient response rates and potential immune-related side effects make it rather challenging to literally bring immunotherapy from bench to bedside. However, it has become evident that, although the immunosuppressive tumor microenvironment (TME) plays a pivotal role in facilitating tumor progression and metastasis, it also provides various potential targets for remodeling the immunosuppressive TME, which can consequently bolster the effectiveness of antitumor response and tumor suppression. Additionally, the particular characteristics of TME, in turn, can be exploited as avenues for designing diverse precise targeting nanomedicines. In general, it is of urgent necessity to deliver nanomedicines for remodeling the immunosuppressive TME, thus improving the therapeutic outcomes and clinical translation prospects of immunotherapy. Herein, we will illustrate several formation mechanisms of immunosuppressive TME. More importantly, a variety of strategies concerning remodeling immunosuppressive TME and strengthening patients' immune systems, will be reviewed. Ultimately, we will discuss the existing obstacles and future perspectives in the development of antitumor immunotherapy. Hopefully, the thriving bloom of immunotherapy will bring vibrancy to further exploration of comprehensive cancer treatment.

Targeting apoptosis to manage acquired resistance to third generation EGFR inhibitors

A significant clinical challenge in lung cancer treatment is management of the inevitable acquired resistance to third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (EGFR-TKIs), such as osimertinib, which have shown remarkable success in the treatment of advanced NSCLC with EGFR activating mutations, in order to achieve maximal response duration or treatment remission. Apoptosis is a major type of programmed cell death tightly associated with cancer development and treatment. Evasion of apoptosis is considered a key hallmark of cancer and acquisition of apoptosis resistance is accordingly a key mechanism of drug acquired resistance in cancer therapy. It has been clearly shown that effective induction of apoptosis is a key mechanism for third generation EGFR-TKIs, particularly osimertinib, to exert their therapeutic efficacies and the development of resistance to apoptosis is tightly associated with the emergence of acquired resistance. Hence, restoration of cell sensitivity to undergo apoptosis using various means promises an effective strategy for the management of acquired resistance to third generation EGFR-TKIs.

Ginsenoside Rh4 Suppressed Metastasis of Lung Adenocarcinoma via Inhibiting JAK2/STAT3 Signaling

Lung adenocarcinoma (LAC) is a common lung cancer with a high malignancy that urgently needs to be treated with effective drugs. Ginsenoside Rh4 exhibits outstanding antitumor activities. However, few studies reported its effects on growth, metastasis and molecular mechanisms in LAC. Here, Rh4 is certified to show a strong anti-LAC efficiency in vitro and in vivo. Results of flow cytometry and Western blot are obtained to exhibited that Rh4 markedly restrained cellular proliferation and colony formation by arresting the cell cycle in the G1 phase. Results from a wound healing assay and transwell assays demonstrated that Rh4 is active in the antimigration and anti-invasion of LAC. The analysis of Western blot, immunofluorescence and RT-qPCR confirmed that Rh4 reverses the epithelial–mesenchymal transition (EMT) through upregulating the gene expression of E-cadherin and downregulating that of snail, N-cadherin and vimentin. In vivo results from immunohistochemistry show consistent trends with cellular studies. Furthermore, Rh4 suppresses the Janus kinases2/signal transducer and activator of the transcription3 (JAK2/STAT3) signaling pathway stimulated by TGF-β1. Silencing the STAT3 signal or co-treating with AG490 both enhanced the EMT attenuation caused by Rh4, which revealed that Rh4 suppressed EMT via inhibiting the JAK2/STAT3 signaling pathway. These findings explore the capacity and mechanism of Rh4 on the antimetastasis of LAC, providing evidence for Rh4 to LAC therapy.

Clinical Significance and Regulation of ERK5 Expression and Function in Cancer

Extracellular signal-regulated kinase 5 (ERK5) is a unique kinase among MAPKs family members, given its large structure characterized by the presence of a unique C-terminal domain. Despite increasing data demonstrating the relevance of the ERK5 pathway in the growth, survival, and differentiation of normal cells, ERK5 has recently attracted the attention of several research groups given its relevance in inflammatory disorders and cancer. Accumulating evidence reported its role in tumor initiation and progression. In this review, we explore the gene expression profile of ERK5 among cancers correlated with its clinical impact, as well as the prognostic value of ERK5 and pERK5 expression levels in tumors. We also summarize the importance of ERK5 in the maintenance of a cancer stem-like phenotype and explore the major known contributions of ERK5 in the tumor-associated microenvironment. Moreover, although several questions are still open concerning ERK5 molecular regulation, different ERK5 isoforms derived from the alternative splicing process are also described, highlighting the potential clinical relevance of targeting ERK5 pathways.

Small molecule ERK5 kinase inhibitors paradoxically activate ERK5 signalling: be careful what you wish for…

ERK5 is a protein kinase that also contains a nuclear localisation signal and a transcriptional transactivation domain. Inhibition of ERK5 has therapeutic potential in cancer and inflammation and this has prompted the development of ERK5 kinase inhibitors (ERK5i). However, few ERK5i programmes have taken account of the ERK5 transactivation domain. We have recently shown that the binding of small molecule ERK5i to the ERK5 kinase domain stimulates nuclear localisation and paradoxical activation of its transactivation domain. Other kinase inhibitors paradoxically activate their intended kinase target, in some cases leading to severe physiological consequences highlighting the importance of mitigating these effects. Here, we review the assays used to monitor ERK5 activities (kinase and transcriptional) in cells, the challenges faced in development of small molecule inhibitors to the ERK5 pathway, and classify the molecular mechanisms of paradoxical activation of protein kinases by kinase inhibitors.

Inhibition of MEK5/ERK5 signaling overcomes acquired resistance to the third generation EGFR inhibitor, osimertinib, via enhancing Bim-dependent apoptosis

The promising therapeutic efficacy of the third generation EGFR inhibitor, osimertinib (AZD9291), for the treatment of patients with EGFR-mutant non-small cell lung cancer (NSCLC) has been demonstrated in the clinic both as first-line and second line therapy. However, inevitable acquired resistance limits its long-term benefit to patients and is thus a significant clinical challenge. The current study focuses on studying the potential role of targeting MEK5-ERK5 signaling in overcoming acquired resistance to osimertinib. Osimertinib and other third generation EGFR inhibitors exerted a rapid and sustained suppressive effect on ERK5 phosphorylation primarily in EGFR-mutant NSCLC cell lines and lost this activity in some osimertinib-resistant cell lines. Osimertinib combined with either ERK5 or MEK5 inhibitors synergistically decreased the survival of osimertinib-resistant cell lines with enhanced induction of apoptosis primarily via augmenting Bim expression. Moreover, the combination effectively inhibited the growth of osimertinib-resistant xenografts in vivo. Together, these findings suggest the potential role of MEK5-ERK5 signaling in modulating development of acquired resistance to osimertinib and value of targeting this signaling as a potential strategy in overcoming acquired resistance to osimertinib and possibly other third generation EGFR inhibitors.

Exosomal miR‑663b exposed to TGF‑β1 promotes cervical cancer metastasis and epithelial‑mesenchymal transition by targeting MGAT3

Transforming growth factor (TGF)‑β1 is a key cytokine affecting the pathogenesis and progression of cervical cancer. Tumor‑derived exosomes contain microRNAs (miRNAs/miRs) that interact with cancer and stromal cells, thereby contributing to tissue remodeling in the tumor microenvironment (TME). The present study was designed to clarify how TGF‑β1 affects tumor biological functions through exosomes released by cervical cancer cells. Deep RNA sequencing found that TGF‑β1 stimulated cervical cancer cells to secrete more miR‑663b‑containing exosomes, which could be transferred into new target cells to promote metastasis. Further studies have shown that miR‑663b directly targets the 3'-untranslated regions (3'‑UTR) of mannoside acetylglucosaminyltransferase 3 (MGAT3) and is involved in the epithelial‑mesenchymal transition (EMT) process. Remarkably, the overexpression of MGAT3 suppressed cervical cancer cell metastasis promoted by exosomal miR‑663b, causing increased expression of epithelial differentiation marker E‑cadherin and decreased expression of mesenchymal markers N‑cadherin and β‑catenin. Throughout our study, online bioinformation tools and dual luciferase reporter assay were applied to identify MGAT3 as a novel direct target of miR‑663b. Exosome PKH67‑labeling experiment verified that exosomal miR‑663b could be endocytosed by cervical cancer cells and subsequently influence its migration and invasion functions which were measured by wound healing and Transwell assays. The expression of miR‑663b and MGAT3 and the regulation of the EMT pathway caused by MGAT3 were detected by quantitative real‑time transcription‑polymerase chain reaction (qPCR) and western blot analysis. These results, thus, provide evidence that cancer cell‑derived exosomal miR‑663b is endocytosed by cervical cancer cells adjacent or distant after TGF‑β1 exposure and inhibits the expression of MGAT3, thereby accelerating the EMT process and ultimately promoting local and distant metastasis.

YY1 regulated transcription-based stratification of gastric tumors and identification of potential therapeutic candidates

Gastric cancer is one of the leading causes of cancer-related death worldwide. The transcription factor YY1 regulates diverse biological processes, including cell proliferation, development, DNA damage responses, and carcinogenesis. This study was designed to explore the role of YY1 regulated transcription in gastric cancer. YY1 silencing in gastric cancer cells has resulted in the inhibition of Wnt/β-catenin, JNK/MAPK, ERK/MAPK, ER, and HIF-1α signaling pathways. Genome-wide mRNA profiling upon silencing the expression YY1 gene in gastric cancer cells and comparison with the previously identified YY1 regulated genes from other lineages revealed a moderate overlap among the YY1 regulated genes. Despite the differing genes, all the YY1 regulated gene sets were expressed in most of the intestinal subtype gastric tumors and a subset of diffuse subtype gastric tumors. Integrative functional genomic analysis of the YY1 gene sets revealed an association among the pathways Wnt/β-catenin, Rapamycin, Cyclin-D1, Myc, E2F, PDGF, and AKT. Further, the drugs capable of inhibiting YY1 mediated transcription were identified as suitable targeted therapeutic candidates for gastric tumors with activated YY1. The data emerging from the investigation would pave the way for the development of YY1-based targeted therapeutics for gastric cancer.

Piperlongumine inhibits the growth of non-small cell lung cancer cells via the miR-34b-3p/TGFBR1 pathway

BACKGROUND

Non-small cell lung cancer is a common type of lung cancer. Piperlongumine (PL), which is extracted from the roots of piperaceae plant, long pepper, and peppercorn, is an alkaloid amide that inhibits tumor growth and metastasis. However, whether it affects lung cancer cells remains unclear.

METHODS

We assessed the effects of PL on the proliferation and apoptosis of A549 and H1299 NSCLC cell lines.

RESULTS

PL was mildly toxic to normal human bronchial epithelial cells and significantly suppressed growth and facilitated apoptosis of A549 and H1299 cells. It also upregulated microRNA (miR)-34b-3p and downregulated the transforming growth factor beta type I receptor (TGFBR1). The dual-luciferase reporter assay showed that TGFBR1 is a target gene of miR-34b-3p. Silencing of miR-34b-3p or overexpression of TGFBR1 partially attenuated the effects of PL on A549 and H1299 cells.

CONCLUSIONS

PL inhibits proliferation and induces apoptosis of A549 and H1299 cells by upregulating miR-34b-3p and modulating TGFBR1 signaling pathway.

Extracellular signal regulated kinase 5 promotes cell migration, invasion and lung metastasis in a FAK-dependent manner

This study was designed to evaluate ERK5 expression in lung cancer and malignant melanoma progression and to ascertain the involvement of ERK5 signaling in lung cancer and melanoma. We show that ERK5 expression is abundant in human lung cancer samples, and elevated ERK5 expression in lung cancer was linked to the acquisition of increased metastatic and invasive potential. Importantly, we observed a significant correlation between ERK5 activity and FAK expression and its phosphorylation at the Ser⁹¹⁰ site. Mechanistically, ERK5 increased the expression of the transcription factor USF1, which could transcriptionally upregulate FAK expression, resulting in FAK signaling activation to promote cell migration. We also provided evidence that the phosphorylation of FAK at Ser⁹¹⁰ was due to ERK5 but not ERK1/2, and we then suggested a role for Ser⁹¹⁰ in the control of cell motility. In addition, ERK5 had targets in addition to FAK that regulate epithelial-to-mesenchymal transition and cell motility in cancer cells. Taken together, our findings uncover a cancer metastasis-promoting role for ERK5 and provide the rationale for targeting ERK5 as a potential therapeutic approach.

The role of contextual signal TGF-β1 inducer of epithelial mesenchymal transition in metastatic lung adenocarcinoma patients with brain metastases: an update on its pathological significance and therapeutic potential

Lung adenocarcinoma (LA) is the most common cause of cancer-related death worldwide. Despite the advances over last decade in new targeted therapies, cancer genetics, diagnostics, staging, and surgical techniques as well as new chemotherapy and radiotherapy protocols, the death rate from LA remains high. The tumour microenvironment is composed of several cytokines, one of which is transforming growth factor β1 (TGF-β1), which modulates and mediates the expression of epithelial-mesenchymal transition (EMT), correlated with invasive growth in LAs, and exhibits its pleiotropic effects through binding to transmembrane receptors TβR-1 (also termed activin receptor-like kinases – ALKs) and TβR-2. Accordingly, there is an urgent need to elucidate the molecular mechanisms associated with the tumoural spreading process and therapeutic resistance of this serious pathology. In this review, we briefly discuss the current role of contextual signal TGF-β1 inducer of epithelial mesenchymal transition in metastatic lung adenocarcinoma patients with brain metastases, and give an overview of our current mechanistic understanding of the TGF-β1-related pathways in brain metastases progression, TGF-β1 pathway inhibitors that could be used for clinical treatment, and examination of models used to study these processes. Finally, we summarise the current progress in the therapeutic approaches targeting TGF-β1.

BTBD7 Downregulates E-Cadherin and Promotes Epithelial-Mesenchymal Transition in Lung Cancer

Metastasis is the leading cause of lung cancer-associated death. Downregulated expression of E-cadherin followed by epithelial-mesenchymal transition (EMT) is critical for metastasis initiation in lung cancer. BTBD7 plays essential roles in lung cancer metastasis, but the mechanisms remain unknown. This study aimed to investigate the relationship between BTBD7 and E-cadherin in lung cancer and explore the role of BTBD7 in EMT. Fresh lung cancer and paracancer tissue specimens were collected from 30 patients, and the expression of BTBD7, E-cadherin, N-cadherin, fibronectin, and vimentin was analyzed by qRT-PCR, western blotting, and immunohistochemistry. A549 and HBE cells were cultured and treated with TGF-β1 for 72 h to induce EMT. Western blotting and qRT-PCR were performed to evaluate the expression of BTBD7, E-cadherin, N-cadherin, fibronectin, and vimentin. Then, A549 cells were treated separately with the BTBD7-ENTER plasmid, BTBD7-siRNA, and paclitaxel. After TGF-β1-induced EMT, the abovementioned markers were analyzed by western blotting and qRT-PCR. Wound healing assays were applied to assess the migration ability of cells in different groups. For animal experiments, A549 cells transfected with the BTBD7-ENTER plasmid were transplanted into BALB/c nude mice. After 4 weeks, all nude mice were sacrificed, and tumor tissues were harvested for qRT-PCR, western blot, and immunohistochemical analyses of the abovementioned markers. All experimental results showed that the levels of BTBD7, N-cadherin, fibronectin, and vimentin were increased in lung cancer tissues and cells, while the E-cadherin level was decreased. Transfection experiments showed that BTBD7 inhibited E-cadherin expression and enhanced EMT. Moreover, the migration capacity of lung cancer cells was increased by the high level of BTBD7. We concluded that BTBD7 is highly expressed during lung cancer development and metastasis and can inhibit the expression of E-cadherin and promote EMT in lung cancer. BTBD7 may thus be a therapeutic target for lung cancer.

Biochanin A protects against PM2.5-induced acute pulmonary cell injury by interacting with the target protein MEK5

Epidemiological studies have shown that exposure to ambient fine particulate matter (PM_2.5) is associated with an increased risk for cardiopulmonary diseases. The MEK5/ERK5 and NF-κB signaling pathways are closely related to the regulation of acute pulmonary cell injury (APCI) and may play an important role in the underlying pathophysiological mechanisms. Related studies have shown that Biochanin A (BCA) effectively interferes with APCI, but the underlying mechanism through which this occurs is not fully understood. Previously, based on proteomic and bioinformatic research, we found the indispensable role of MEK5 in mediating remission effects of BCA against PM_2.5-induced lung toxicity. Therefore, using A549 adenocarcinoma human alveolar basal epithelial cells (A549 cells), we combined western blot and qRT-PCR to study the protective signaling pathways induced by BCA, indicating that MEK5/ERK5 and NF-κB are both involved in mediating APCI in response to PM_2.5, and MEK5/ERK5 positively activated NF-κB and its downstream cellular regulatory factors. BCA significantly suppressed PM_2.5-induced upregulation of MEK5/ERK5 expression and phosphorylation and activation of NF-κB. Furthermore, due to the specificity of the MEK5/ERK5 protein structure, the binding sites and binding patterns of BCA and MEK5 were analyzed using molecular docking correlation techniques, which showed that there are stable hydrogen bonds between BCA and the PB1 domain of MEK5 as well as its kinase domain. BCA forms a stable complex with MEK5, which has potential effects on MEKK2/3-MEK5-ERK5 ternary interactions, p62/αPKC-mediated NF-κB regulation, and inhibition of MEK5 target protein phosphorylation. Therefore, our study suggests that MEK5 is an important regulator of intracellular signaling of APCI in response to PM_2.5 exposure. BCA may exert anti-APCI activity by targeting MEK5 to inhibit activation of the MEK5/ERK5/NF-κB signaling pathway.

FMNL1 down-regulation suppresses bone metastasis through reducing TGF-β1 expression in non-small cell lung cancer (NSCLC)

Approximately 40% of patients with non-small cell lung cancer (NSCLC) develop bone metastasis. The formin protein formin-like 1 (FMNL1) plays a key role in the pathogenic processes of hematopoietic malignancies, and has been reported to be associated with the progression of multiple types of cancer. In the study, we found that FMNL1 expression was markedly up-regulated in primary NSCLC samples, and stronger expression of FNML1 was detected in bone metastasis. Reducing FMNL1 expression significantly suppressed cell proliferation in NSCLC cells. We also investigated the functional effects of FMNL1 knockdown on the inhibition of migration and invasion by meditating the expression of epithelial to mesenchymal transition (EMT)-associated signals in NSCLC cells. The transforming growth factor-β1 (TGF-β1)/SMADs signaling pathway was repressed in FMNL1-knockdown NSCLC cells. Further studies indicated that additional treatment with TGF-β1 could markedly abrogate FMNL1 knockdown-induced suppression of migration and invasion in NSCLC cells. In addition, NSCLC cell-induced osteoclastogenesis was also inhibited by FMNL1 deletion, as evidenced by the down-regulated expression of tartrate-resistant acid phosphatase (TRAP) and NFATc1. In vivo studies confirmed the results that FMNL1 knockdown markedly limited tumor growth. Importantly, decreasing FMNL1 reduced bone metastasis ability in vivo. Therefore, our results demonstrated that suppressing FMNL1 expression could inhibit bone metastasis in NSCLC through blocking TGF-β1 signaling, and FMNL1 might be a novel target for developing effective therapeutic strategy to limit the bone metastasis of NSCLC.

Impact of ERK5 on the Hallmarks of Cancer

Extracellular signal-regulated kinase 5 (ERK5) belongs to the mitogen-activated protein kinase (MAPK) family that consists of highly conserved enzymes expressed in all eukaryotic cells and elicits several biological responses, including cell survival, proliferation, migration, and differentiation. In recent years, accumulating lines of evidence point to a relevant role of ERK5 in the onset and progression of several types of cancer. In particular, it has been reported that ERK5 is a key signaling molecule involved in almost all the biological features of cancer cells so that its targeting is emerging as a promising strategy to suppress tumor growth and spreading. Based on that, in this review, we pinpoint the hallmark-specific role of ERK5 in cancer in order to identify biological features that will potentially benefit from ERK5 targeting.

YdjC chitooligosaccharide deacetylase homolog induces keratin reorganization in lung cancer cells: involvement of interaction between YDJC and CDC16

Lung cancer is a fatal disease with a high mortality rate. The perinuclear reorganization of keratin 8 (K8) is an important biochemical phenomenon reflecting changes in the physical properties of metastatic cancer. However, there is not much of information about the regulatory molecules involved in phosphorylation and perinuclear reorganization of K8.

In this study, we investigated the role and molecular mechanisms of YdjC chitooligosaccha- ride deacetylase homolog (YDJC) in sphingosylphosphorylcholine (SPC)-induced phosphorylation and reorganization of K8, and migration and invasion (SPC-induced events). SPC induced expression of YDJC in a dose- and time-dependent manner. Gene silencing of YDJC suppressed SPC-induced events. YDJC overexpression induced the SPC-induced events. YDJC deacetylase dominant negative mutant (YDJCD13A) did not induce SPC-induced events. YDJC siRNA reduced ERK activation and overexpression of YDJC induced ERK activation. The siRNA of ERK1 or ERK2 suppressed YDJC-induced phosphorylation and reorganization of K8, and migration and invasion. Co-immunoprecipitation revealed that YDJC binds to CDC16. Interestingly, CDC16 siRNA induced SPC-induced events. Overexpression of CDC16 blocked SPC-induced events. KMPLOT analysis based on public microarray data revealed the poor prognosis of lung cancer patients with high expression of YDJC compared with patients with low expression of YDJC.

The collective results indicate that YDJC is involved in SPC-induced events in A549 lung cancer cells by interacting with CDC16. YDJC overexpression might be involved in the progression of lung cancer. These results also suggest that suppression of YDJC or boosting of CDC16 interaction with YDJC might be a novel way to prevent progression of lung cancer.

FPPS mediates TGF-β1-induced non-small cell lung cancer cell invasion and the EMT process via the RhoA/Rock1 pathway

Farnesyl pyrophosphate synthase (FPPS), a key enzyme in the mevalonate pathway, was recently shown to play a role in cancer progression. However, its role in non-small cell lung cancer (NSCLC) metastasis and the underlying mechanism remain unclear. In this study, FPPS expression was significantly correlated with TNM stage, and metastasis. Inhibition or knockdown of FPPS blocked TGF-β1-induced cell invasion and epithelial-to-mesenchymal transition (EMT) process. FPPS expression of FPPS was induced by TGF-β1 and FPPS promoted cell invasion and EMT via the RhoA/Rock1 pathway. In conclusion, FPPS mediates TGF-β1-induced lung cancer cell invasion and EMT via the RhoA/Rock1 pathway. These findings suggest new treatment strategies to reduce mortality associated with metastasis in patients with NSCLC.

Advanced oxidation protein products induce hepatocyte epithelial-mesenchymal transition via a ROS-dependent, TGF-β/Smad signaling pathway

Epithelial-mesenchymal transition (EMT) occurs during the progression of liver fibrosis in response to chronic liver injury. However, the molecular mechanism underlying the regulation of hepatocyte EMT remains unclear. The aim of this study was to determine whether advanced oxidation protein products (AOPP) had an effect on hepatocyte EMT. The human L02 hepatocyte cell line and hepatocytes from normal Sprague-Dawley rats were challenged with AOPP treatment in both in vitro and in vivo studies. The expression of cell and molecular markers of EMT in L02 hepatocytes were studied using Western blotting, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assays. Hepatocyte migratory potential was analyzed using a wound healing assay. Intracellular reactive oxygen species (ROS) were detected using the dichlorofluorescein (DCF) assay. In liver tissue sections, expression of EMT markers was evaluated using immunohistochemistry, and collagen was assessed using histochemical staining with Masson's trichrome. The findings were that AOPP treatment resulted in EMT in hepatocytes, which was associated with reduced expression of E-cadherin, increased expression of vimentin, increased deposition of collagen protein, and enhanced cell migration in vivo and in vitro. AOPP was also found to promote migration in L02 cells, and to promote the production of ROS and the activation of TGF-βR and Smad signaling. Inhibition of the generation of intracellular ROS and TGF-β receptor blocking could reverse AOPP-induced EMT in hepatocytes. This study has identified a novel mechanism in the regulation of hepatocyte EMT, and the findings may have implications for the control of liver fibrosis.

Oncogenic signaling of MEK5-ERK5

Mitogen-activated protein kinases (MAPKs) regulate diverse cellular processes including proliferation, cell survival, differentiation, and apoptosis. While conventional MAPK constituents have well-defined roles in oncogenesis, the MEK5 pathway has only recently emerged in cancer research. In this review, we consider the MEK5 signaling cascade, focusing specifically on its involvement in drug resistance and regulation of aggressive cancer phenotypes. Moreover, we explore the role of MEK5/ERK5 in tumorigenesis and metastatic progression, discussing the discrepancies in preclinical studies and assessing its viability as a therapeutic target for anti-cancer agents.

Mammalian Target of Rapamycin (mTOR) Regulates Transforming Growth Factor-β1 (TGF-β1)-Induced Epithelial-Mesenchymal Transition via Decreased Pyruvate Kinase M2 (PKM2) Expression in Cervical Cancer Cells

BACKGROUND Epithelial-mesenchymal transition (EMT) plays an important role in cancer tumorigenesis. Transforming growth factor β1 (TGF-β1) can induced EMT, which could increase tumor migration and invasion. Moreover, recent studies have been proven that mammalian target of rapamycin (mTOR) is a critical regulator of EMT. We investigated the mechanisms of mTOR in transforming growth factor β1 (TGF-β1)-induced EMT in cervical cancer cells. MATERIAL AND METHODS HeLa and SiHa cells were treated with 10 ng/ml TGF-β1 to induce EMT. Then, they were treated with or without rapamycin. CCK8 assay was performed to determine cell proliferation. Cell migration was detected by wound-healing assay; apoptosis was analyzed by flow cytometry; mTOR inhibitors inhibited mTOR pathway to assess the expression of E-cadherin, Vimentin STAT3, Snail2, p-p70s6k, and PKM2 expression. RESULTS TGF-β1 promoted proliferation and migration, and attenuated apoptosis in cervical carcinoma cells. Rapamycin abolished TGF-β1-induced EMT cell proliferation and migration and reversed TGF-β1-induced EMT. E-cadherin were suppressed, whereas Vimentin and PKM2 were increased in HeLa and SiHa cells after stimulation with TGF-β1. Moreover, mTOR was activated in the process of TGF-β1-induced EMT. Rapamycin inhibited the phosphorylation of p70s6k. Furthermore, inhibition of the mTOR pathway decreased PKM2 expression. CONCLUSIONS Inhibition of the mTOR pathway abolished TGF-β1-induced EMT and reduced mTOR/p70s6k signaling, which downregulated PKM2 expression. Our results provide novel mechanistic insight into the anti-tumor effects of inhibition of mTOR.

Cx32 reverses epithelial-mesenchymal transition in doxorubicin-resistant hepatocellular carcinoma

Recently, epithelial-mesenchymal transition (EMT) has been reported to be an important mechanism of drug resistance in numerous types of cancer cells, including hepatocellular carcinoma (HCC). However, the underlying mechanisms remain to be fully elucidated. Connexin (Cx)32 plays a crucial role in hepatocarcinogenesis. The present study investigated the role of Cx32 in the regulation of chemotherapy-induced EMT in HCC. We found that the expression levels of Cx32 and E-cadherin were clearly decreased in HCC tissues compared with the corresponding paracancerous tissues, while the expression level of vimentin was significantly enhanced in HCC tissues. The expression of Cx32 had a strong correlation with the expression of E-cadherin and vimentin. In an in vitro study, a doxorubicin (DOX)-resistant liver cell line HepG2/DOX was established from parental HepG2 cells. The results showed that HepG2/DOX cells acquired EMT characteristics, with a decreased expression level of E-cadherin and an enhanced expression level of vimentin, and possessed high migratory abilities and invasiveness. Meanwhile, Cx32 was significantly decreased in the HepG2/DOX cells. Knockdown of Cx32 by shRNA in HepG2 cells induced EMT, while overexpression of Cx32 converted EMT to mesenchymal-epithelial transition (MET) in the HepG2/DOX cells. These results suggest that Cx32 is an important regulator of DOX-induced EMT in HCC. Cx32 could be considered as a novel target to reverse DOX resistance in HCC.