Repression of YAP by NCTD disrupts NSCLC progression

Hippo pathway in non-small cell lung cancer: mechanisms, potential targets, and biomarkers

Lung cancer is the primary contributor to cancer-related deaths globally, and non-small cell lung cancer (NSCLC) constitutes around 85% of all lung cancer cases. Recently, the emergence of targeted therapy and immunotherapy revolutionized the treatment of NSCLC and greatly improved patients' survival. However, drug resistance is inevitable, and extensive research has demonstrated that the Hippo pathway plays a crucial role in the development of drug resistance in NSCLC. The Hippo pathway is a highly conserved signaling pathway that is essential for various biological processes, including organ development, maintenance of epithelial balance, tissue regeneration, wound healing, and immune regulation. This pathway exerts its effects through two key transcription factors, namely Yes-associated protein (YAP) and transcriptional co-activator PDZ-binding motif (TAZ). They regulate gene expression by interacting with the transcriptional-enhanced associate domain (TEAD) family. In recent years, this pathway has been extensively studied in NSCLC. The review summarizes a comprehensive overview of the involvement of this pathway in NSCLC, and discusses the mechanisms of drug resistance, potential targets, and biomarkers associated with this pathway in NSCLC.

Transcription factors in fibroblast plasticity and CAF heterogeneity

In recent years, research focused on the multifaceted landscape and functions of cancer-associated fibroblasts (CAFs) aimed to reveal their heterogeneity and identify commonalities across diverse tumors for more effective therapeutic targeting of pro-tumoral stromal microenvironment. However, a unified functional categorization of CAF subsets remains elusive, posing challenges for the development of targeted CAF therapies in clinical settings.The CAF phenotype arises from a complex interplay of signals within the tumor microenvironment, where transcription factors serve as central mediators of various cellular pathways. Recent advances in single-cell RNA sequencing technology have emphasized the role of transcription factors in the conversion of normal fibroblasts to distinct CAF subtypes across various cancer types.This review provides a comprehensive overview of the specific roles of transcription factor networks in shaping CAF heterogeneity, plasticity, and functionality. Beginning with their influence on fibroblast homeostasis and reprogramming during wound healing and fibrosis, it delves into the emerging insights into transcription factor regulatory networks. Understanding these mechanisms not only enables a more precise characterization of CAF subsets but also sheds light on the early regulatory processes governing CAF heterogeneity and functionality. Ultimately, this knowledge may unveil novel therapeutic targets for cancer treatment, addressing the existing challenges of stromal-targeted therapies.

The role of selected non-coding RNAs in the biology of non-small cell lung cancer

Lung cancer is the second most frequently diagnosed cancer worldwide and a leading cause of cancer-related deaths. Non-small cell lung carcinoma (NSCLC) represents 85% of all cases. Accumulating evidence highlights the outstanding role of non-coding RNA (ncRNA) in regulating the tumorigenesis process by modulating crucial signaling pathways. Micro RNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA) are either up- or downregulated in lung cancer patients and can promote or suppress the progression of the disease. These molecules interact with messenger RNA (mRNA) and with each other to regulate gene expression and stimulate proto-oncogenes or silence tumor suppressors. NcRNAs provide a new strategy to diagnose or treat lung cancer patients and multiple molecules have already been identified as potential biomarkers or therapeutic targets. The aim of this review is to summarize the current evidence on the roles of miRNA, lncRNA and circRNA in NSCLC biology and present their clinical potential.

Targeting YAP/TAZ in Combination with PD-L1 Immune Checkpoint Inhibitors in Non-Small Cell Lung Cancer (NSCLC)

The survival of non-small cell lung cancer (NSCLC) patients has improved in the last decade as a result of introducing new therapeutics, such as immune checkpoint inhibitors, in the clinic. Still, some NSCLC patients do not benefit from these therapies due to intrinsic resistance or the development of acquired resistance and their malignant disease progresses. Further research on the molecular underpinnings of NSCLC pathobiology is required in order to discover clinically relevant molecular targets that regulate tumor immunity and to develop reasonable therapeutic combinations that will promote the efficacy of immune checkpoint inhibitors. Yes-associated Protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ), the final effectors of the Hippo signaling transduction pathway, are emerging as key players in NSCLC development and progression. Herein, we overview studies that have investigated the oncogenic role of YAP/TAZ in NSCLC, focusing on immune evasion, and highlight the therapeutic potential of combining YAP/TAZ inhibitory agents with immune checkpoint inhibitors for the management of NSCLC patients.

Targeting YAP1/TAZ in nonsmall-cell lung carcinoma: From molecular mechanisms to precision medicine

Accumulating evidence has underscored the importance of the Hippo-YAP1 signaling in lung tissue homeostasis, whereas its deregulation induces tumorigenesis. YAP1 and its paralog TAZ are the key downstream effectors tightly controlled by the Hippo pathway. YAP1/TAZ exerts oncogenic activities by transcriptional regulation via physical interaction with TEAD transcription factors. In solid tumors, Hippo-YAP1 crosstalks with other signaling pathways such as Wnt/β-catenin, receptor tyrosine kinase cascade, Notch and TGF-β to synergistically drive tumorigenesis. As YAP1/TAZ expression is significantly correlated with unfavorable outcomes for the patients, small molecules have been developed for targeting YAP1/TAZ to get a therapeutic effect. In this review, we summarize the recent findings on the deregulation of Hippo-YAP1 pathway in nonsmall cell lung carcinoma, discuss the molecular mechanisms of its dysregulation in leading to tumorigenesis, explore the therapeutic strategies for targeting YAP1/TAZ, and provide the research directions for deep investigation. We believe that detailed delineation of Hippo-YAP1 regulation in tumorigenesis provides novel insight for accurate therapeutic intervention.

Niclosamide Revitalizes Sorafenib through Insulin-like Growth Factor 1 Receptor (IGF-1R)/Stemness and Metabolic Changes in Hepatocellular Carcinoma

Sorafenib is the first approved systemic targeting agent for advanced HCC; however, when used alone, drug resistance can result in considerably reduced efficacy. Here, we demonstrate that niclosamide, an antihelminthic agent approved by the US Food and Drug Administration, can be repurposed to increase sorafenib sensitivity in sorafenib-resistant HCC cells. We generated sorafenib-resistant HCC cell lines (HepG2215_R and Hep3B_R) with elevated IGF-1R levels and strong properties in terms of stemness and epithelial-mesenchymal transition. Niclosamide was found to increase sorafenib sensitivity effectively in both cell lines and their organoids. The underlying mechanism involves the modulation of cancer stemness, IGF-1R/p-IGF1R/OCT4, and metabolic changes. The combination of sorafenib and niclosamide, but not linsitinib, effectively suppressed the IGF-1R/OCT4 expressions, yielded a synergistic combination index (CI), and attenuated stemness-related properties such as secondary tumor sphere formation and cell migration in sorafenib-resistant HCC cells. Notably, niclosamide significantly suppressed the sorafenib-induced IGF-1R phosphorylation prompted by IGF-1 treatment. Niclosamide effectively downregulated the sorafenib-induced gene expression associated with glycolysis (GLUT1, HK2, LDHA, and PEPCK), stemness (OCT4), and drug resistance (ABCG2) and enhanced the ability of sorafenib to reduce the mitochondrial membrane potential in vitro. The synergistic effect of a combination of niclosamide and sorafenib in vivo was further demonstrated by the decreased tumor size and tumor volume resulting from apoptosis regulation. Our results suggest that niclosamide can enhance sorafenib sensitivity in sorafenib-resistant HCC cells through IGF-1R/stemness regulation and metabolic changes. Our findings highlight a practical clinical strategy for enhancing sorafenib sensitivity in HCC.

Targeting Transcription Factors in Cancer: From "Undruggable" to "Druggable"

Deregulation of transcription factors is critical to hallmarks of cancer. Genetic mutations, gene fusions, amplifications or deletions, epigenetic alternations, and aberrant post-transcriptional modification of transcription factors are involved in the regulation of various stages of carcinogenesis, including cancer initiation, progression, and metastasis. Thus, targeting the dysfunctional transcription factors may lead to new cancer therapeutic strategies. However, transcription factors are conventionally considered as "undruggable." Here, we summarize the recent progresses in understanding the regulation of transcription factors in cancers and strategies to target transcription factors and co-factors for preclinical and clinical drug development, particularly focusing on c-Myc, YAP/TAZ, and β-catenin due to their significance and interplays in cancer.

Review targeted drug delivery systems for norcantharidin in cancer therapy

Norcantharidin (NCTD) is a demethylated derivative of cantharidin (CTD), the main anticancer active ingredient isolated from traditional Chinese medicine Mylabris. NCTD has been approved by the State Food and Drug Administration for the treatment of various solid tumors, especially liver cancer. Although NCTD greatly reduces the toxicity of CTD, there is still a certain degree of urinary toxicity and organ toxicity, and the poor solubility, short half-life, fast metabolism, as well as high venous irritation and weak tumor targeting ability limit its widespread application in the clinic. To reduce its toxicity and improve its efficacy, design of targeted drug delivery systems based on biomaterials and nanomaterials is one of the most feasible strategies. Therefore, this review focused on the studies of targeted drug delivery systems combined with NCTD in recent years, including passive and active targeted drug delivery systems, and physicochemical targeted drug delivery systems for improving drug bioavailability and enhancing its efficacy, as well as increasing drug targeting ability and reducing its adverse effects.

Graphical Abstract

Norcantharidin Nanostructured Lipid Carrier (NCTD-NLC) Suppresses the Viability of Human Hepatocellular Carcinoma HepG2 Cells and Accelerates the Apoptosis

Malignant tumors have become the main cause of harm to human life and health. Development for new antitumor drugs and the exploration to drug carriers are becoming the concerned focus. In this study, we exploited our experiments to explore the effect of NCTD-NLC on liver cancer cells: the HepG2 cells cultured in vitro were given with NCTD-NLC administration; then, the estimation on cellular proliferation and apoptosis was accomplished through MTT and flow cytometry. Six hours after the administration, we performed the High Performance Liquid Chromatography (HPLC) detection to estimate the NCTD content in the heart, liver, spleen, lung, kidney and plasma of rats. Then, our outcomes showed that NCTD-NLC had a notable inhibitory effect on HepG2 cells, leading to a gradually decreased cellular viability. Cell viability was negatively correlated with NCTD-NLC concentration. Along with the concentration increasing, significantly increasing cellular apoptosis and gradually decreasing cellular viability were observed. The apoptosis rate was positively correlated with the concentration of NCTD-NLC. On the basis of the data we obtained, we found that the group with NCTD-NLC tail vein injection had an obvious advantage in drug delivery when compared with other groups. Through the tumorigenesis test to nude mice, we found that the tumor inhibition rate of the NCTD-NLC tail vein injection group had a 27.48% elevation in contrast to the NCTD gavage group, and it was also the group with the best tumor inhibition efficiency. In conclusion, the NCTD-NLC prepared in this study had a mighty inhibitory effect towards HepG2 cellular viability and an accelerating work on apoptosis. Tail vein injection of NCTD-NLC has the best drug delivery effect.

An overview of the crosstalk between YAP and cGAS-STING signaling in non-small cell lung cancer: it takes two to tango

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway is recognized as a main mediator bridging innate and adaptive immunity, recent advances have expanded its roles to anti-tumor immunity and carcinogenesis. Loss of cGAS-STING signaling in non-small cell lung cancer (NSCLC) leads to enhanced tumorigenicity and decreased cytotoxic T lymphocyte infiltration. Apart from its anticancer response, persistent overreaction of cGAS-STING signaling promotes progression of certain inflammation-aggravated cancers. Activation of the pro-inflammatory nucleic acid sensing pathway can trigger Hippo pathway, which mediates the inactivation of Yes-associated protein 1 (YAP1) and its paralogue transcriptional co-regulators with PDZ-binding motif (TAZ, also known as WWTR1), and subsequent suppression of tumorigenesis. Active YAP acts as a transcriptional driver in bolstering immunosuppressive cytokines to evade immune surveillance and promote occurrence of preneoplasia. It is reasonable that aggressive tumors co-opt these regulators to generate few immunogenic antigens and drive tumorigenic behaviors via a highly cooperative manner. Given their multifaced roles, we profile the molecular biology characteristic and current status underpinning oncogenic YAP, review its crosstalk roles with cGAS/STING pathway in NSCLC, and summarize the major clinical investigations in NSCLC with TCGA database.

The Hippo pathway in cancer: YAP/TAZ and TEAD as therapeutic targets in cancer

Tumorigenesis is a highly complex process, involving many interrelated and cross-acting signalling pathways. One such pathway that has garnered much attention in the field of cancer research over the last decade is the Hippo signalling pathway. Consisting of two antagonistic modules, the pathway plays an integral role in both tumour suppressive and oncogenic processes, generally via regulation of a diverse set of genes involved in a range of biological functions. This review discusses the history of the pathway within the context of cancer and explores some of the most recent discoveries as to how this critical transducer of cellular signalling can influence cancer progression. A special focus is on the various recent efforts to therapeutically target the key effectors of the pathway in both preclinical and clinical settings.

A Yes-Associated Protein (YAP) and Insulin-Like Growth Factor 1 Receptor (IGF-1R) Signaling Loop Is Involved in Sorafenib Resistance in Hepatocellular Carcinoma

The role of a YAP-IGF-1R signaling loop in HCC resistance to sorafenib remains unknown.

METHOD

Sorafenib-resistant cells were generated by treating naïve cells (HepG2215 and Hep3B) with sorafenib. Different cancer cell lines from databases were analyzed through the ONCOMINE web server. BIOSTORM-LIHC patient tissues (46 nonresponders and 21 responders to sorafenib) were used to compare YAP mRNA levels. The HepG2215_R-derived xenograft in SCID mice was used as an in vivo model. HCC tissues from a patient with sorafenib failure were used to examine differences in YAP and IGF-R signaling.

RESULTS

Positive associations exist among the levels of YAP, IGF-1R, and EMT markers in HCC tissues and the levels of these proteins increased with sorafenib failure, with a trend of tumor-margin distribution in vivo. Blocking YAP downregulated IGF-1R signaling-related proteins, while IGF-1/2 treatment enhanced the nuclear translocation of YAP in HCC cells through PI3K-mTOR regulation. The combination of YAP-specific inhibitor verteporfin (VP) and sorafenib effectively decreased cell viability in a synergistic manner, evidenced by the combination index (CI).

CONCLUSION

A YAP-IGF-1R signaling loop may play a role in HCC sorafenib resistance and could provide novel potential targets for combination therapy with sorafenib to overcome drug resistance in HCC.

Context-dependent roles of YAP/TAZ in stem cell fates and cancer

Hippo effectors YAP and TAZ control cell fate and survival through various mechanisms, including transcriptional regulation of key genes. However, much of this research has been marked by conflicting results, as well as controversy over whether YAP and TAZ are redundant. A substantial portion of the discordance stems from their contradictory roles in stem cell self-renewal vs. differentiation and cancer cell survival vs. apoptosis. In this review, we present an overview of the multiple context-dependent functions of YAP and TAZ in regulating cell fate decisions in stem cells and organoids, as well as their mechanisms of controlling programmed cell death pathways in cancer.

YAP accelerates vascular senescence via blocking autophagic flux and activating mTOR

Yes-associated protein (YAP), a major effector of the Hippo signalling pathway, is widely implicated in vascular pathophysiology processes. Here, we identify a new role of YAP in the regulation of vascular senescence. The inhibition or deficiency and overexpression of YAP were performed in human umbilical vein endothelial cells (HUVECs) and isolated vascular tissues. Cellular and vascular senescence was assessed by analysis of the senescence-associated β-galactosidase (SA-β-gal) and expression of senescence markers P16, P21, P53, TERT and TRF1. We found that YAP was highly expressed in old vascular tissues, inhibition and knockdown of YAP decreased senescence, while overexpression of YAP increased the senescence in both HUVECs and vascular tissues. In addition, autophagic flux blockage and mTOR pathway activation were observed during YAP-induced HUVECs and vascular senescence, which could be relieved by the inhibition and knockdown of YAP. Moreover, YAP-promoted cellular and vascular senescence could be relieved by mTOR inhibition. Collectively, our findings indicate that YAP may serve as a potential therapeutic target for ageing-associated cardiovascular disease.

Transcriptional co-activators YAP/TAZ: Potential therapeutic targets for metastatic breast cancer

Breast cancer is the most commonly diagnosed cancer among women. Although routine and targeted therapies have improved the survival rate, there are still considerable challenges in the treatment of breast cancer. Metastasis is the leading cause of death in patients diagnosed with breast cancer. Yes-associated protein (YAP) and/or PDZ binding motif (TAZ) are usually abnormally activated in breast cancer leading to a variety of effects on tumour promotion, such as epithelial-mesenchymal transition, cancer stem cell production and drug-resistance. The abnormal activation of YAP/TAZ can affect metastasis-related processes and promote cancer progression and metastasis by interacting with some metastasis-related factors and pathways. In this article, we summarise the evidence that YAP/TAZ regulates breast cancer metastasis, its post-translational modification mechanisms, and the latest advances in the treatment of YAP/TAZ-related breast cancer metastasis, besides providing a new strategy of YAP/TAZ-based treatment of human breast cancer.

Norcantharidin: research advances in pharmaceutical activities and derivatives in recent years

Cantharidin (CTD) is the main bioactive component of Cantharides, which is called Banmao in Traditional Chinese Medicine (TCM). Norcantharidin (NCTD) is a structural modifier of CTD. To compare with CTD, NCTD has lighter side effects and stronger bioactivity in anti-cancer through inhibiting cell proliferation, causing apoptosis and autophagy, overwhelming migration and metastasis, affecting immunity as well as lymphangiogenesis. Examples of these effects include suppressing Protein Phosphatase 2A and modulating Wnt/beta catenin signal, with Caspase family proteins, AMPK pathway and c-Met/EGFR pathway involving respectively. Moreover, NCTD has the effects of immune enhancement, anti-platelet aggregation and inhibition of renal interstitial fibrosis with distinct signaling pathways. The immunological effects induced by NCTD are related to the regulation of macrophage polarization and LPS-mediated immune response. The antiplatelet activity that NCTD induced is relevant to the inhibition of platelet signaling and the downregulation of α2 integrin. Furthermore, some of novel derivatives designed and synthesized artificially show stronger biological activities (e.g., anticancer effect, enzyme inhibition effect, antioxidant effect) and lower toxicity than NCTD itself. Plenty of literatures have reported various pharmacological effects of NCTD, particularly the anticancer effect, which has been widely concerned in clinical application and laboratory research. In this review, the pharmaceutical activities and derivatives of NCTD are discussed, which can be reference for further study.

Insight into norcantharidin, a small-molecule synthetic compound with potential multi-target anticancer activities

Norcantharidin (NCTD) is a demethylated derivative of cantharidin, which is an anticancer active ingredient of traditional Chinese medicine, and is currently used clinically as a routine anti-cancer drug in China. Clarifying the anticancer effect and molecular mechanism of NCTD is critical for its clinical application. Here, we summarized the physiological, chemical, pharmacokinetic characteristics and clinical applications of NCTD. Besides, we mainly focus on its potential multi-target anticancer activities and underlying mechanisms, and discuss the problems existing in clinical application and scientific research of NCTD, so as to provide a potential anticancer therapeutic agent for human malignant tumors.

MicroRNA‑608 sensitizes non‑small cell lung cancer cells to cisplatin by targeting TEAD2

Cisplatin has been widely used as a conventional treatment for patients with non-small cell lung cancer (NSCLC). However, primary and acquired cisplatin resistances are frequently developed during the treatment of patients with NSCLC, leading to an increased mortality rate. Accumulating evidence demonstrated that aberrantly expressed microRNAs (miRs) are involved in the development of chemoresistance. In the present study, sensitivity of NSCLC cells to cisplatin was identified to increase following overexpression of miR-608. Conversely, sensitivity to cisplatin was reduced following miR-608 knockdown. Reverse transcription-quantitative PCR and western blotting analyses identified that TEA domain transcription factor 2 (TEAD2), a key regulator of cell stemness, was negatively regulated by miR-608 in NSCLC cells. By repressing TEAD2, miR-608 decreased the expression level of several target genes of the Hippo-yes-associated protein signaling pathway. Furthermore, TEAD2 mRNA was confirmed to be targeted by miR-608 in NSCLC cells via a dual-luciferase reporter assay. Importantly, the increased cisplatin sensitivity induced by miR-608 overexpression was reversed by transfection of TEAD2 in NSCLC cells. The present data suggested that miR-608 may represent a novel candidate biomarker for the evaluation of cisplatin sensitivity in patients with NSCLC.

Epidermal Growth Factor Receptor (EGFR) Pathway, Yes-Associated Protein (YAP) and the Regulation of Programmed Death-Ligand 1 (PD-L1) in Non-Small Cell Lung Cancer (NSCLC)

The epidermal growth factor receptor (EGFR) pathway is a well-studied oncogenic pathway in human non-small cell lung cancer (NSCLC). A subset of advanced NSCLC patients (15–55%) have EGFR-driven mutations and benefit from treatment with EGFR-tyrosine kinase inhibitors (TKIs). Immune checkpoint inhibitors (ICIs) targeting the PD-1/PDL-1 axis are a new anti-cancer therapy for metastatic NSCLC. The anti-PD-1/PDL-1 ICIs showed promising efficacy (~30% response rate) and improved the survival of patients with metastatic NSCLC, but the role of anti-PD-1/PDL-1 ICIs for EGFR mutant NSCLC is not clear. YAP (yes-associated protein) is the main mediator of the Hippo pathway and has been identified as promoting cancer progression, drug resistance, and metastasis in NSCLC. Here, we review recent studies that examined the correlation between the EGFR, YAP pathways, and PD-L1 and demonstrate the mechanism by which EGFR and YAP regulate PD-L1 expression in human NSCLC. About 50% of EGFR mutant NSCLC patients acquire resistance to EGFR-TKIs without known targetable secondary mutations. Targeting YAP therapy is suggested as a potential treatment for NSCLC with acquired resistance to EGFR-TKIs. Future work should focus on the efficacy of YAP inhibitors in combination with immune checkpoint PD-L1/PD-1 blockade in EGFR mutant NSCLC without targetable resistant mutations.

Knockdown of YAP inhibits growth in Hep-2 laryngeal cancer cells via epithelial-mesenchymal transition and the Wnt/β-catenin pathway

BACKGROUND

Yes-associated protein (YAP) plays a crucial role in tumour development and it is the main effector of the Hippo signalling pathway. However, the mechanism underlying YAP downregulation in laryngeal cancer is still unclear. In our previous study, we found that YAP, compared with adjacent tissues, was expressed higher in laryngeal cancer and was also closely associated with histological differentiation, TNM stage and poor prognosis.

METHODS

In this study, we attempted to determine whether silenced YAP could downregulate human laryngeal carcinoma Hep-2 cells progression. YAP was downregulated in Hep-2 cells by shRNA, and the malignant ability of Hep-2 was assessed in vitro and in vivo.

RESULTS

In vitro, CCK-8, colony formation and wound healing assays showed that downregulation of YAP significantly reduced the rates of proliferation, migration, and invasion in Hep-2 cells. Downregulation of YAP distinctly induced G2/M cycle arrest and increased the rate of apoptosis. Accordingly, western blot assay suggested that the expression of DKK1, vimentin and β-catenin was significantly decreased after YAP downregulated treatment, thereby indicating that YAP mediated the EMT programme and the Wnt/β-catenin signalling pathway in carcinoma of the larynx. Furthermore, silencing of YAP suppressed Hep-2 cell tumourigenesis and metastasis in vivo.

CONCLUSION

In summary, our findings demonstrated the proliferation of YAP downregulation and the invasion of Hep-2 cells via downregulating the Wnt/β-catenin pathway in vitro and in vivo, suggesting that YAP may provide a potential therapeutic strategy for the treatment of laryngeal cancer.

A brief review: some compounds targeting YAP against malignancies

YAP, acting as a crucial transcription factor in nucleus, regulates the organ size, tissue homeostasis and tumorigenesis. Dysregulation of Hippo-YAP pathway brings a significant impact on the occurrence and development of various tumor types. Moreover, regulation of YAP/TAZ far exceeds the core kinase of the Hippo pathway, and gradually opens up new therapeutic targets. For the moment, chemotherapy together with radiotherapy act as routine methods to prolong the lives of cancer patients. Seeking more effective anti-neoplastic agents seems to be the urgent problem. This brief review focuses on the research progress of YAP inhibitors as the antineoplastic targets. Small molecule inhibitors or drugs have been discovered including verteporfin, dasatinib, statins, A35, JQ1, norcantharidin, agave, MLN8237, dobutamine and peptide-based YAP inhibitors. We are trying to seek novel therapies from the relationship between known drugs and potential mechanisms.

UBE2C, Directly Targeted by miR-548e-5p, Increases the Cellular Growth and Invasive Abilities of Cancer Cells Interacting with the EMT Marker Protein Zinc Finger E-box Binding Homeobox 1/2 in NSCLC

Background: Recent evidence indicates that UBE2C participates in carcinogenesis by regulating the cell cycle, apoptosis, metastasis, and transcriptional processes. Additionally, miR-548e-5p dysregulation plays a vital role in tumor progression. However, the molecular mechanism via which UBE2C is directly targeted by miR-548-5p, resulting in increase in cellular growth and invasiveness of cancer cells, and its interactions with the epithelial-mesenchymal transition (EMT) marker protein ZEB1/2 in non-small cell lung cancer (NSCLC) is not understood.

Methods: Expression of UBE2C and miR-548e-5p was analyzed using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The protein level of UBE2C and ZEB1/2 was analyzed using western blotting and immunofluorescence staining. Cellular proliferation was detected using the cell counting kit 8 (CCK8) and 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Cell migration, invasion, and growth were analyzed using the wound healing and transwell assay. Promoter activity and transcription was analyzed using the luciferase reporter assay. Chromatin immunoprecipitation was used to detect binding of UBE2C to 5′UTR-ZEB1/2.

Results: We observed that 4,5-ubiquitin-conjugating enzyme E2C (UBE2C) expression was higher in NSCLC tissue than in the adjacent normal tissue and was associated with increased cell proliferation and invasion. UBE2C enhanced NSCLC progression and metastasis by affecting the cell cycle and inhibiting apoptosis. We also observed that miR-548e-5p was significantly downregulated in lung cancer tissue specimens, which decreased the expression of its direct substrate, UBE2C. Moreover, miR-548e-5p overexpression and UBE2C under-expression significantly suppressed lung cancer cell proliferation, migration, and invasion. Luciferase reporter and chromatin immunoprecipitation assays indicated that miR-548e-5p directly binds to the 3′-UTR of UBE2C and decreases UBE2C mRNA expression. Furthermore, UBE2C knockdown downregulated the mesenchymal marker vimentin and upregulated the epithelial marker E-cadherin. Bioinformatics assays, coupled with western blotting and luciferase assays, revealed that UBE2C directly binds to the 5′-untranslated region (UTR) of the transcript of the E-cadherin repressor ZEB1/2 and promotes EMT in lung cancer cells.

Conclusion: miR-548e-5p directly binds to the 3′-UTR of UBE2C and decreases UBE2C mRNA expression. UBE2C is an oncogene that promotes EMT in lung cancer cells by directly targeting the 5′-UTR of the transcript encoding the E-cadherin repressor ZEB1/2. miR-548e-5p, UBE2C, and ZEB1/2 constitute the miR-548e-5p-UBE2C-ZEB1/2 signal axis, which enhances cancer cell invasiveness by directly interacting with e EMT marker proteins. We believe that the miR-548e-5p-UBE2C-ZEB1/2 signal axis may be a suitable diagnostic marker and a potential target for lung cancer therapy.

Dual inhibition of Akt and ERK signaling induces cell senescence in triple-negative breast cancer

Activated Akt and ERK signaling pathways are closely related to breast cancer progression, and Akt or ERK inhibition induces cell senescence. However, the crosstalk between the Akt and ERK signaling pathways in cell senescence and how to simultaneously suppress Akt and ERK signaling in triple-negative breast cancer (TNBC) are undefined. In this study, we found that norcantharidin (NCTD) effectively induced cell senescence and cell cycle arrest in TNBC in vitro, which was accompanied by a decline in phosphorylated Akt and ERK1/2 and a rise in p21 and p16. The inhibitors LY294002 and U0126 imitated the effect of NCTD when these two inhibitors were combined regardless of crosstalk between these two signaling pathways. In addition, NCTD inhibited the growth of xenografts via downregulation of phosphorylated Akt and ERK1/2 and upregulation of p21 in vivo. However, NCTD upregulated the level of soluble signaling factors of the senescence-associated secretory phenotype (SASP) in a NF-κB-independent manner. Collectively, these findings demonstrate that NCTD induced cell senescence and cell cycle arrest mainly by simultaneously blocking Akt and ERK signaling in TNBC, suggesting that NCTD may be used as a potential adjuvant therapy in TNBC.

UBE2C Induces Cisplatin Resistance via ZEB1/2-Dependent Upregulation of ABCG2 and ERCC1 in NSCLC Cells

Objectives

Cisplatin (DDP) is one of the most commonly used chemotherapeutic drugs for several cancers, including non-small-cell lung cancer (NSCLC). However, resistance to DDP eventually develops, limiting its further application. New therapy targets are urgently needed to reverse DDP resistance.

Methods

The mRNA expression of UBE2C, ZEB1/2, ABCG2, and ERCC1 was analyzed by reverse transcription-polymerase chain reaction. The protein levels of these molecules were analyzed by Western blotting and immunofluorescent staining. Cell proliferation was detected by CCK8 and MTT assays. Cell migration and invasion were analyzed by wound healing assay and Transwell assays. Promoter activities and gene transcription were analyzed by luciferase reporter assay.

Results

In this study, we examined the effect of UBE2C and ZEB1/2 expression levels in DDP-resistant cells of NSCLC. We confirmed that aberrant expression of UBE2C and ZEB1/2 plays a critical role in repressing the DDP sensitivity to NSCLC cells. Additionally, knockdown of UBE2C significantly sensitized resistant cells to DDP by repressing the expression of ZEB1/2. Mechanistic investigations indicated that UBE2C transcriptionally regulated ZEB1/2 by accelerating promoter activity. This study revealed that ZEB1/2 promotes the epithelial mesenchymal transition and expression of ABCG2 and ERCC1 to participate in UBE2C-mediated NSCLC DDP-resistant cell progression, metastasis, and invasion.

Conclusion

UBE2C may be a novel therapy target for NSCLC for sensitizing cells to the chemotherapeutic agent DDP.

The Ambivalent Function of YAP in Apoptosis and Cancer

Yes-associated protein, a core regulator of the Hippo-YAP signaling pathway, plays a vital role in inhibiting apoptosis. Thus, several studies and reviews suggest that yes-associated protein is a good target for treating cancer. Unfortunately, more and more evidence demonstrates that this protein is also an essential contributor of p73-mediated apoptosis. This questions the concept that yes-associated protein is always a good target for developing novel anti-cancer drugs. Thus, the aim of this review was to evaluate the clinical relevance of yes-associated protein for cancer pathophysiology. This review also summarized the molecules, processes and drugs, which regulate Hippo-YAP signaling and discusses their effect on apoptosis. In addition, issues are defined, which should be addressed in the future in order to provide a solid basis for targeting the Hippo-YAP signaling pathway in clinical trials.

EMT induced by loss of LKB1 promotes migration and invasion of liver cancer cells through ZEB1-induced YAP signaling

Liver cancer cells often exhibit mesenchymal phenotypes, a critical phenotypic alteration of cancer cells termed the epithelial-mesenchymal transition (EMT). To examine whether liver kinase B1 (LKB1) serves a potential role in EMT in liver carcinogenesis, in the present study, it was determined that the expression of LKB1 decreased in the hepatocellular carcinoma (HCC) cell line, compared with a normal liver cell line. LKB1 overexpression decreased cell motility and invasiveness. Furthermore, the loss of LKB1 induced the expression of several EMT marker proteins, including that of Zinc Finger E-Box Binding Homeobox 1 (ZEB1). Notably, the expression of Yes-associated protein (YAP) was positively associated with that of ZEB1 in LKB1-knockdown cells with a mesenchymal phenotype. Here, we describe the direct regulation of the Hippo pathway effector YAP by ZEB1. The findings of the present study demonstrate that ZEB1 regulates the expression of YAP and regulates the expression of downstream target genes to promote malignant progression.

Knockdown of lncRNA GHET1 suppresses cell proliferation, invasion and LATS1/YAP pathway in non small cell lung cancer

BACKGROUND

The aim in this study was to explore the role of long non-coding RNA GHET1 in development of non small cell lung cancer (NSCLC).

METHODS

LncRNA GHET1 expression levels were analyzed by qRT-PCR in tumor tissues and adjacent normal tissues in NSCLC. Measuring the cell proliferation and invasion abilities by CCK8, cell colony formation and transwell invasion assays. Relative protein expression was analyzed by western blot assays.

RESULTS

Expression of lncRNA GHET1 was notably higher in NSCLC tissues compared with adjacent normal tissues by using qRT-PCR analyses. Higher lncRNA GHET1 expression associated with lymph node metastasis, TNM stage and showed poor outcome in NSCLC patients. Knockdown of lncRNA GHET1 suppressed cell proliferation and invasion capacity and Epithelial-Mesenchymal Transition (EMT) phenomenon of NSCLC cells. Moreover, we demonstrated that knockdown of lncRNA GHET1 suppresses LATS1/YAP pathway signaling pathway by downregulating YAP1 expression in NSCLC cells.

CONCLUSIONS

GHET1 predicted a poor outcome and acted as a tumor-promoting gene in NSCLC. Thus, inhibition of GHET1 may be a potential target of NSCLC treatment.

The miR 495-UBE2C-ABCG2/ERCC1 axis reverses cisplatin resistance by downregulating drug resistance genes in cisplatin-resistant non-small cell lung cancer cells

Cisplatin (DDP) resistance has become the leading cause of mortality in non-small cell lung cancer (NSCLC). miRNA dysregulation significantly contributes to tumor progression. In this study, we found that miR-495 was significantly downregulated in lung cancer tissue specimens. This study aimed to elucidate the functions, direct target genes, and molecular mechanisms of miR-495 in lung cancer. miR-495 downregulated its substrate UBE2C through direct interaction with UBE2C 3′- untranslated region. UBE2C is a proto-oncogene activated in lung cancer; however, its role in chemotherapeutic resistance is unclear. Herein, UBE2C expression levels were higher in DDP-resistant NSCLC cells; this was associated with the proliferation, invasion, and DDP resistance in induced cisplatin-resistant NSCLC cells. Furthermore, epithelial–mesenchymal transitions (EMT) contributed to DDP resistance. Moreover, UBE2C knockdown downregulated vimentin. In contrast, E-cadherin was upregulated. Importantly, miR-495 and UBE2C were associated with cisplatin resistance. We attempted to evaluate their effects on cell proliferation and cisplatin resistance. We also performed EMT, cell migration, and invasion assays in DDP-resistant NSCLC cells overexpressing miR-495 and under-expressing UBE2C. Furthermore, in silico assays coupled with western blotting and luciferase assays revealed that UBE2C directly binds to the 5′-UTR of the drug-resistance genes ABCG2 and ERCC1. Furthermore, miR-495 downregulated ABCG2 and ERCC1 via regulation of UBE2C. Together, the present results indicate that the miR495-UBE2C-ABCG2/ERCC1 axis reverses DDP resistance via downregulation of anti-drug genes and reducing EMT in DDP-resistant NSCLC cells.

Functional significance of Hippo/YAP signaling for drug resistance in colorectal cancer

Colorectal cancer is a leading cause of cancer-related death worldwide. While early stage colorectal cancer can be removed by surgery, patients with advanced disease are treated by chemotherapy, with 5-Fluorouracil (5-FU) as a main ingredient. However, most patients with advanced colorectal cancer eventually succumb to the disease despite some responded initially. Thus, identifying molecular mechanisms responsible for drug resistance will help design novel strategies to treat colorectal cancer. In this study, we analyzed an acquired 5-FU resistant cell line, LoVo-R, and determined that elevated expression of YAP target genes is a major alteration in the 5-FU resistant cells. Hippo/YAP signaling, a pathway essential for cell polarity, is an important regulator for tissue homeostasis, organ size, and stem cells. We demonstrated that knockdown of YAP1 sensitized LoVo-R cells to 5-FU treatment in cultured cells and in mice. The relevance of our studies to colorectal cancer patients is reflected by our discovery that high expression of YAP target genes in the tumor was associated with an increased risk of cancer relapse and poor survival in a larger cohort of colorectal cancer patients who underwent 5-FU-related chemotherapy. Taken together, we demonstrate a critical role of YAP signaling for drug resistance in colorectal cancer.

Deregulation of UBE2C-mediated autophagy repression aggravates NSCLC progression

The roles of aberrantly regulated autophagy in human malignancy and the mechanisms that initiate and sustain the repression of autophagy in carcinogenesis are less well defined. Activation of the oncogene UBE2C and repression of autophagy are concurrently underlying the initiation, progression, and metastasis of lung cancer and exploration of essential association of UBE2C with autophagy will confer more options in searching novel molecular therapeutic targets in lung cancer. Here we report that aberrant activation of UBE2C in lung tumors from patients associates with adverse prognosis and enhances cell proliferation, clonogenicity, and invasive growth of NSCLC. UBE2C selectively represses autophagy in NSCLC and disruption of UBE2C-mediated autophagy repression attenuates cell proliferation, clonogenicity, and invasive growth of NSCLC. Autophagy repression is essentially involved in UBE2C-induced cell proliferation, clonogenicity, and invasive growth of NSCLC. Interference of UBE2C-autophagy repression axis by Norcantharidin arrests NSCLC progression. UBE2C is repressed post-transcriptionally via tumor suppressor miR-381 and epitranscriptionally stabilized with maintenance of lower m⁶A level within its mature RNAs due to the upregulation of m⁶A demethylase ALKBH5 in NSCLC. Collectively, our results indicated that deregulated UBE2C-autophagy repression axis drives NSCLC progression which renders varieties of potential molecular targets in cancer therapy of NSCLC.

Norcantharidin reverses cisplatin resistance and inhibits the epithelial mesenchymal transition of human non‑small lung cancer cells by regulating the YAP pathway

Non-small cell lung cancer (NSCLC) accounts for >80% of all lung cancer cases, which are the leading cause of cancer-related mortality worldwide. The clinical efficacy of available therapies for NSCLC is often limited due to the development of resistance to anticancer drugs, particularly to cisplatin (DDP). Norcantharidin (NCTD) is a traditional Chinese medicine used in the treatment of many types of cancer, to which patients do not develop resistance. The aim of the present study was to examine the potential synergistic effects of NCTD and DPP on the viability of the the DDP-resistant NSCLC cell line, A549/DDP. We further explored the potential underlying mechanisms by examining the expression of the oncogene, Yes-associated protein 1 (YAP), whose activation was recently found to be associated with drug resistance. We further examined a series of human lung cancer cell lines and tissues from patients with lung cancer, which revealed that YAP activation contributed to lung cancer initiation, progression and metastasis, and was associated with a poor prognosis, and confering resistance against targeted therapies. Moreover, YAP expression was evaluated in the A549/DDP cells treated with NCTD, DDP, or both drugs. The combined treatment significantly sensitized the A549/DDP cells to DDP-induced growth inhibition by reducing YAP promoter activity (based on transcriptional expression) and the expression of its target genes, connective tissue growth factor (CTGF) and cysteine rich angiogenic inducer 61 (CYR61). Furthermore, compared to the individual treatments, combined treatment increased cell apoptosis and senescence, and decreased epithelial-to-mesenchymal transition and the cell migratory and invasive ability. On the whole, our data indicate that the application of NCTD with reverses DDP resistance and thus, this combined treatment may have promising prospects for use in improving the outcome of patients with NSCLC.

YAP and TAZ in Lung Cancer: Oncogenic Role and Clinical Targeting

Lung cancer is the leading cause of cancer death in the world and there is no current treatment able to efficiently treat the disease as the tumor is often diagnosed at an advanced stage. Moreover, cancer cells are often resistant or acquire resistance to the treatment. Further knowledge of the mechanisms driving lung tumorigenesis, aggressiveness, metastasization, and resistance to treatments could provide new tools for detecting the disease at an earlier stage and for a better response to therapy. In this scenario, Yes Associated Protein (YAP) and Trascriptional Coactivator with PDZ-binding motif (TAZ), the final effectors of the Hippo signaling transduction pathway, are emerging as promising therapeutic targets. Here, we will discuss the most recent advances made in YAP and TAZ biology in lung cancer and, more importantly, on the newly discovered mechanisms of YAP and TAZ inhibition in lung cancer as well as their clinical implications.

Suppression of YAP by DDP disrupts colon tumor progression

Colon cancer is a commonly diagnosed cancer that often has a poor prognosis. Combined with the development of drug resistance to cancer treatment agents the treatment efficacy of colon cancer can be limited. Activation of the oncogene YAP has been shown to be related to colon cancer progression and is associated with poor prognosis, drug resistance and metastasis, even under treatment. Cisplatin (DDP) is a commonly used drug that can control carcinoma progression, although its mechanisms are poorly understood. In the present study, we examined whether DDP specifically suppressed YAP in order to inhibit colon carcinoma progression. Our data revealed that Mst/Yap signaling was unusually activated in colon cancers, promoting cell proliferation and invasion. DDP treatment decreased the expression of YAP at both the transcriptional and post-translational levels, leading to cell cycle arrest, apoptosis and senescence in cancer cells, in addition to decreasing epithelial-to-mesenchymal transition, cell motility and in vitro cell invasion and migration. Ultimately, DDP increased the expression of E-cadherin and decreased the expression of vimentin. The present study also revealed that post-translational regulation of YAP phosphorylation controlled the subcellular distribution between the nucleus and the cytoplasm. In conclusion, the findings of the present study revealed that DDP was a suitable therapeutic candidate for colon cancer that specifically targets the Mst/Yap signaling pathway.

Induction of endoplasmic reticulum stress and mitochondrial dysfunction dependent apoptosis signaling pathway in human renal cancer cells by norcantharidin

Previous studies reported that norcantharidin (NCTD) has anti-tumor effects. We investigated the antitumor effects and underlying mechanism of NCTD on human renal cancer in vitro and in vivo. NCTD significantly decreased renal cancer cell viability by induction of apoptosis, as determined by the MTT assay and annexin V/PI staining. NCTD treatment of 786-O and A-498 cells altered the expression of caspase family proteins and PARP. Moreover, NCTD induced mitochondrial depolarization, which was accompanied by an increased level of Bax and decreased levels of Bcl-2 and Mcl-1. NCTD induced endoplasmic reticulum (ER) stress by increasing the expression of Grp78, p-elF2α, ATF4, and CHOP. Pretreatment with an ER stress inhibitor (salubrinal) significantly attenuated the effect of NCTD. NCTD also induced activation of the AKT pathway in 786-O and A-498 cells. Overexpression of AKT partly reversed the effect of NCTD on apoptosis. NCTD treatment led to decreased expression of Bcl-2 and Mcl-1, and increased expression of Bax, cleaved-caspase-9, cleaved-PARP, and p-elF2α. Our in vivo studies demonstrated that NCTD significantly inhibited tumor growth in a nude mouse xenograft model. Taken together, our results suggest that NCTD is a potential anti-tumor agent for treatment of renal carcinoma.

Dual roles of yes-associated protein (YAP) in colorectal cancer

Yes-associated protein (YAP) is a downstream effector molecule of a newly emerging tumour suppressor pathway called the Hippo pathway. YAP is a transcriptional co-activator and mis-expressed in various cancers, including colorectal cancer (CRC). Accumulating studies show that the high expression of nuclear YAP is linked with tumour progression and decreased survival. Nuclear YAP can interact with other transcription factors to promote cancer cell proliferation, apoptosis, metastasis and maintenance of stemness. Therefore, YAP has the potential to be a tumour biomarker or therapeutic target for CRC. However, recently, a number of studies have supported a contradictory role for YAP as a tumour suppressor, demonstrating inhibition of the tumorigenesis of CRC, involvement in promoting cell apoptosis, and inhibiting the maintenance of intestinal stem cells and inflammatory activity. In these studies, high expression of YAP was highly correlated with worse survival in CRC. In this review, we will comprehensively summarize and analyse these paradoxical reports, and discuss both the oncogenic and tumour suppressor functions of YAP in the differential status of CRC progression. Further investigation into the mechanisms responsible for the dual function of YAP will be of great value in the prevention, early diagnosis, and therapy of CRC.

Highly expressed long non-coding RNA FOXD2-AS1 promotes non-small cell lung cancer progression via Wnt/β-catenin signaling

Non-small cell lung cancer (NSCLC) is one of the most common and aggressive tumors around the world. Long-noncoding RNAs (lncRNAs) have been recently shown to play important roles in regulating numerous biological processes including tumor progression. However, the role of lncRNA FOXD2-AS1 in NSCLC remains unclear. In this study, we found that lncRNA FOXD2-AS1 is significantly up-regulated in NSCLC tissues. Loss- and gain-function assays revealed that FOXD2-AS1 promotes NSCLC cell growth and NSCLC tumor progression. Furthermore, we also revealed that FOXD2-AS1 modulates Wnt/β-catenin signaling in NSCLC cells. Taken together, we conclude that lncRNA FOXD2-AS1 promotes NSCLC progression though Wnt/β-catenin signaling. These results suggest that lncRNA FOXD2-AS1 might act as a novel therapeutic target for NSCLC treatment.