The retinamide VNLG-152 inhibits f-AR/AR-V7 and MNK-eIF4E signaling pathways to suppress EMT and castration-resistant prostate cancer xenograft growth

Estrogen receptor beta suppresses the androgen receptor oncogenic effects in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer associated with poor prognosis and limited treatment options. The androgen receptor (AR) has emerged as a potential therapeutic target for luminal androgen receptor (LAR) TNBC. However, multiple studies have claimed that anti-androgen therapy for AR-positive TNBC only has limited clinical benefits. This study aimed to investigate the role of AR in TNBC and its detailed mechanism.

METHODS

Immunohistochemistry and TNBC tissue sections were applied to investigate AR and nectin cell adhesion molecule 4 (NECTIN4) expression in TNBC tissues. Then, in vitro and in vivo assays were used to explore the function of AR and estrogen receptor beta (ERβ) in TNBC. Chromatin immunoprecipitation sequencing (ChIP-seq), co-immunoprecipitation (co-IP), molecular docking method, and luciferase reporter assay were performed to identify key molecules that affect the function of AR.

RESULTS

Based on the TNBC tissue array analysis, we revealed that ERβ and AR were positive in 21.92% (32/146) and 24.66% (36/146) of 146 TNBC samples, respectively, and about 13.70% (20/146) of TNBC patients were ERβ positive and AR positive. We further demonstrated the pro-tumoral effects of AR on TNBC cells, however, the oncogenic biology was significantly suppressed when ERβ transfection in LAR TNBC cell lines but not in AR-negative TNBC. Mechanistically, we identified that NECTIN4 promoter -42 bp to -28 bp was an AR response element, and that ERβ interacted with AR thus impeding the AR-mediated NECTIN4 transcription which promoted epithelial-mesenchymal transition in tumor progression.

CONCLUSIONS

This study suggests that ERβ functions as a suppressor mediating the effect of AR in TNBC prognosis and cell proliferation. Therefore, our current research facilitates a better understanding of the role and mechanisms of AR in TNBC carcinogenesis.

MNK, mTOR or eIF4E-selecting the best anti-tumor target for blocking translation initiation

Overexpression of eIF4E is common in patients with various solid tumors and hematologic cancers. As a potential anti-cancer target, eIF4E has attracted extensive attention from researchers. At the same time, mTOR kinases inhibitors and MNK kinases inhibitors, which are directly related to regulation of eIF4E, have been rapidly developed. To explore the optimal anti-cancer targets among MNK, mTOR, and eIF4E, this review provides a detailed classification and description of the anti-cancer activities of promising compounds. In addition, the structures and activities of some dual-target inhibitors are briefly described. By analyzing the different characteristics of the inhibitors, it can be concluded that MNK1/2 and eIF4E/eIF4G interaction inhibitors are superior to mTOR inhibitors. Simultaneous inhibition of MNK and eIF4E/eIF4G interaction may be the most promising anti-cancer method for targeting translation initiation.

VNLG-152R and its deuterated analogs potently inhibit/repress triple/quadruple negative breast cancer of diverse racial origins in vitro and in vivo by upregulating E3 Ligase Synoviolin 1 (SYVN1) and inducing proteasomal degradation of MNK1/2

Triple-negative breast cancer (TNBC) and its recently identified subtype, quadruple negative breast cancer (QNBC), collectively account for approximately 13% of reported breast cancer cases in the United States. These aggressive forms of breast cancer are associated with poor prognoses, limited treatment options, and lower overall survival rates. In previous studies, our research demonstrated that VNLG-152R exhibits inhibitory effects on TNBC cells both in vitro and in vivo and the deuterated analogs were more potent inhibitors of TNBC cells in vitro. Building upon these findings, our current study delves into the molecular mechanisms underlying this inhibitory action. Through transcriptome and proteome analyses, we discovered that VNLG-152R upregulates the expression of E3 ligase Synoviolin 1 (SYVN1), also called 3-hydroxy-3-methylglutaryl reductase degradation (HRD1) in TNBC cells. Moreover, we provide genetic and pharmacological evidence to demonstrate that SYVN1 mediates the ubiquitination and subsequent proteasomal degradation of MNK1/2, the only known kinases responsible for phosphorylating eIF4E. Phosphorylation of eIF4E being a rate-limiting step in the formation of the eIF4F translation initiation complex, the degradation of MNK1/2 by VNLG-152R and its analogs impedes dysregulated translation in TNBC cells, resulting in the inhibition of tumor growth. Importantly, our findings were validated in vivo using TNBC xenograft models derived from MDA-MB-231, MDA-MB-468, and MDA-MB-453 cell lines, representing different racial origins and genetic backgrounds. These xenograft models, which encompass TNBCs with varying androgen receptor (AR) expression levels, were effectively inhibited by oral administration of VNLG-152R and its deuterated analogs in NRG mice. Importantly, in direct comparison, our compounds are more effective than enzalutamide and docetaxel in achieving tumor growth inhibition/repression in the AR+ MDA-MD-453 xenograft model in mice. Collectively, our study sheds light on the involvement of SYVN1 E3 ligase in the VNLG-152R-induced degradation of MNK1/2 and the therapeutic potential of VNLG-152R and its more potent deuterated analogs as promising agents for the treatment of TNBC across diverse patient populations.

SP1/RNASEH2A accelerates the development of hepatocellular carcinoma by regulating EMT

Background

The expression level of Ribonuclease H2, subunit A (RNASEH2A) in hepatocellular carcinoma (HCC) has been reported, but the function of RNASEH2A on HCC cells development and the related molecular mechanisms remain unclear. Herein, we intend to explore the upstream regulator of RNASEH2A and its role in the HCC progression.

Methods

GEPIA website was employed to determine the level of RNASEH2A in HCC tissues and get a survival analysis. After reducing RNASEH2A expression by RNA interference, cell counting kit-8, colony formation, Western blot, Transwell and wound healing assays were performed to estimate the malignant properties of HCC cells. The transcriptional factor of RNASEH2A was predicted by UCSC and JASPAR database and confirmed by dual luciferase assay and Ch-IP assay. The expression level of EMT pathway related molecules was determined by western blotting.

Results

An increased expression of RNASEH2A was presented in HCC and predicted worse prognosis of HCC patients. Functionally, the results demonstrated that depletion of RNASEH2A suppressed HCC cell proliferation, cell cycle, migration and invasion. Moreover, we illustrated that SP1 targeted to the promoter of RNASEH2A and modulated its expression in HCC cell lines. RNASEH2A knockdown counteracted the function of SP1 overexpression in modulating HCC cell growth, cell cycle, and mobility. Then, our data showed that the SP1/RNASEH2A axis affected the malignant behaviors of HCC cells by regulating EMT process.

Conclusions

In summary, these results demonstrated that RNASEH2A promoted HCC cells development through regulating EMT process and was transcriptionally modulated by SP1.

An Aptamer against MNK1 for Non-Small Cell Lung Cancer Treatment

Lung cancer is the leading cause of cancer-related death worldwide. Its late diagnosis and consequently poor survival make necessary the search for new therapeutic targets. The mitogen-activated protein kinase (MAPK)-interacting kinase 1 (MNK1) is overexpressed in lung cancer and correlates with poor overall survival in non-small cell lung cancer (NSCLC) patients. The previously identified and optimized aptamer from our laboratory against MNK1, apMNKQ2, showed promising results as an antitumor drug in breast cancer in vitro and in vivo. Thus, the present study shows the antitumor potential of apMNKQ2 in another type of cancer where MNK1 plays a significant role, such as NSCLC. The effect of apMNKQ2 in lung cancer was studied with viability, toxicity, clonogenic, migration, invasion, and in vivo efficacy assays. Our results show that apMNKQ2 arrests the cell cycle and reduces viability, colony formation, migration, invasion, and epithelial-mesenchymal transition (EMT) processes in NSCLC cells. In addition, apMNKQ2 reduces tumor growth in an A549-cell line NSCLC xenograft model. In summary, targeting MNK1 with a specific aptamer may provide an innovative strategy for lung cancer treatment.

Retracted: Up-regulated Linc00472 suppresses development of lung cancer cell via inhibition of MiR-196b-5p

The role of linc00472 in lung cancer (LC) has been rarely reported. We aimed to study the role of linc00472 in LC progression. Expressions of linc00472 and miR-196b-5p in LC cell lines were measured by qRT-PCR. The targeting relationship between linc00472 and miR-196b-5p was determined by Starbase and dual-luciferase reporter. The viability, migration, invasion, and apoptosis of LC cells were determined using CCK-8 assay, scratch test, transwell assay, and flow cytometry, respectively. The levels of epithelial-to-mesenchymal transition (EMT)-related proteins and apoptosis-related proteins in LC cells were determined by western blot. Down-regulated linc00472 was observed in five LC cell lines. Linc00472 overexpression suppressed viability, migration, invasion and EMT process, but elevated apoptotic rate in LC cells. MiR-196b-5p mimic promoted viability, migration, invasion, and EMT process, but decreased apoptotic rate, which was reversed by up-regulated linc00472. Linc00472 functioned as a cancer suppressor via negatively regulating miR-196b-5p of LC cells.

Translation initiation and its relationship with metabolic mechanisms in cancer development, progression and chemoresistance

Pathways that regulate protein homeostasis (proteostasis) in cells range from mRNA processing to protein degradation; perturbations in regulatory mechanisms of these pathways can lead to oncogenic cellular processes. Protein synthesis modulation failures are common phenomena in cancer cells, wherein specific conditions that promote the translation of protein factors promoting carcinogenesis are present. These specific conditions may be favored by metabolic lipid alterations like those found in metabolic syndrome and obesity. Protein translation modifications have been described in obesity, favoring the translation of protein targets that benefit lipid accumulation; a determining factor is the activity of the cap-binding eukaryotic translation initiation factor 4E (eIF4E), a crosstalk in protein translation and lipogenesis. Besides, alterations of protein translation initiation steps are critical participants for the development of both pathogenic conditions, cancer, and obesity. This chapter is focused on the regulation of recognition and processing of carcinogenic-mRNA and the connections among lipid metabolism and cell signaling pathways that promote oncogenesis, tumoral microenvironment generation and potentially the development of chemoresistance. We performed an in-depth analysis of events, such as those occurring in obesity and dyslipidemias, that may influence protein translation, driving the recognition of certain mRNAs and favoring cancer development and chemoresistance.

Novel deuterated Mnk1/2 protein degrader VNLG-152R analogs: Synthesis, In vitro Anti-TNBC activities and pharmacokinetics in mice

A new and improved synthesis of lead Mnk1/2 protein degrader, VNLG-152R, 4-(±)-(1H-imidazole-1-yl)-N-(4-fluorophenyl)-(E)-retinamide (1) has been developed from commercially available 4-oxo-ATRA (8). This procedure was also utilized to synthesize the seven possible deuterated analogs of compound 1 (11-17). The deuterated analogs were either better or equipotent to 1 in in vitro antiproliferative activities against MDA-MB-231 and MDA-MB-468 human TNBC cells. The Mnk1/2 degraders were equally effective as a standard TNBC therapy (paclitaxel). Importantly, the expression of Mnk1, peIF4E and their associated downstream targets, including cyclin D1 and Bcl2, were strongly decreased in compound 1/analogs (11-17)-treated TNBC cells signifying inhibition of Mnk1-eIF4E signaling. More importantly, we showed that deuterated analogs, 12, 16 and 17 possess improved pharmacokinetics parameters following oral administration to CD-1 female mice compared to the parent non-deuterated compound 1, thus addressing the rapid clearance (short half-life and short residence time) pharmacokinetic inadequacy of compound 1.

Synthetic Retinoids as Potential Therapeutics in Prostate Cancer-An Update of the Last Decade of Research: A Review

Prostate cancer (PC) is the second most common tumor in males. The search for appropriate therapeutic options against advanced PC has been in process for several decades. Especially after cessation of the effectiveness of hormonal therapy (i.e., emergence of castration-resistant PC), PC management options have become scarce and the prognosis is poor. To overcome this stage of disease, an array of natural and synthetic substances underwent investigation. An interesting and promising class of compounds constitutes the derivatives of natural retinoids. Synthesized on the basis of the structure of retinoic acid, they present unique and remarkable properties that warrant their investigation as antitumor drugs. However, there is no up-to-date compilation that consecutively summarizes the current state of knowledge about synthetic retinoids with regard to PC. Therefore, in this review, we present the results of the experimental studies on synthetic retinoids conducted within the last decade. Our primary aim is to highlight the molecular targets of these compounds and to identify their potential promise in the treatment of PC.

MiR-9-3p regulates the biological functions and drug resistance of gemcitabine-treated breast cancer cells and affects tumor growth through targeting MTDH

This study explored the role of MTDH in regulating the sensitivity of breast cancer cell lines to gemcitabine (Gem) and the potential miRNAs targeting MTDH. The expression of MTDH in cancer tissues and cells was detected by immunohistochemical staining or qRT-PCR. The target genes for MTDH were predicted by bioinformatics and further confirmed by dual-luciferase reporter assay and qRT-PCR. Cancer cells were transfected with siMTDH, MTDH, miR-9-3p inhibitor, or mimics and treated by Gem, then CCK-8, colony formation assay, tube formation assay, flow cytometry, wound healing assay, and Transwell were performed to explore the effects of MTDH, miR-9-3p, and Gem on cancer cell growth, apoptosis, migration, and invasion. Expressions of VEGF, p53, cleaved caspase-3, MMP-2, MMP-9, E-Cadherin, N-Cadherin, and Vimentin were determined by Western blot. MTDH was high-expressed in cancer tissues and cells, and the cells with high-expressed MTDH were less sensitive to Gem, while silencing MTDH expression significantly promoted the effect of Gem on inducing apoptosis, inhibiting cell migration, invasion, and growth, and on regulating protein expressions of cancer cells. Moreover, miR-9-3p had a targeted binding relationship with MTDH, and overexpressed miR-9-3p greatly promoted the toxic effects of Gem on cancer cells and expressions of apoptosis-related proteins, whereas overexpressed MTDH partially reversed such effects of overexpressed miR-9-3p. The study proved that miR-9-3p regulates biological functions, drug resistance, and the growth of Gem-treated breast cancer cells through targeting MTDH.

Natural Compound Shikonin Induces Apoptosis and Attenuates Epithelial to Mesenchymal Transition in Radiation-Resistant Human Colon Cancer Cells

Radiation resistance represents an imperative obstacle in the treatment of patients with colorectal cancer, which remains difficult to overcome. Here, we explored the anti-proliferative and migration-inhibiting properties of the natural product shikonin on a radiation-resistant human colon carcinoma cell line (SNU-C5RR). Shikonin reduced the viability of these cells in a dose-dependent manner; 38 μM of shikonin was determined as the half-maximal inhibitory concentration. Shikonin induced apoptotic cell death, as demonstrated by increased apoptotic body formation and the number of TUNEL-positive cells. Moreover, shikonin enhanced mitochondrial membrane depolarization and Bax expression and also decreased Bcl-2 expression with translocation of cytochrome c from mitochondria into the cytosol. In addition, shikonin activated mitogen-activated protein kinases, and their specific inhibitors reduced the cytotoxic effects of shikonin. Additionally, shikonin decreased the migration of SNU-C5RR cells via the upregulation of E-cadherin and downregulation of N-cadherin. Taken together, these results suggest that shikonin induces mitochondria-mediated apoptosis and attenuates epithelial-mesenchymal transition in SNU-C5RR cells.

Circular RNA circHIPK3 promotes breast cancer progression via sponging MiR-326

Background: This study investigated the potential molecular mechanism of circular RNA HIPK3 (circHIPK3) in breast cancer (BCa). Methods: BCa cells were transfected with miR-326 mimic, miR-326 inhibitor, circHIPK3, sicircHIPK3. The expressions of circHIPK3 and miR-326 in BCa tissues and BCa cell lines were determined by RT-qPCR. Cell viability, colony formation, migration, invasion, and apoptosis of the cells were detected by CCK-8 and colony formation, wound-healing, transwell and flow cytometric assays, respectively. The relationship between circHIPK3 and miR-326 was analyzed and confirmed by circInteractome, dual-luciferase reporter, RT-qPCR, Pearson's correlation assays. Western blot and RT-qPCR were performed to determine the expressions of apoptosis-related molecules (Bcl-2, Bax, and cleaved Caspase-3) and EMT-related molecules (E-cadherin, N-cadherin, and Vimentin) in the BCa cells and tumor tissues. The tumor growth in mice was examined in a xenograft tumor model in which Ki-67 expression was determined by immunohistochemistry (IHC). Results: In BCa, the expression of circHIPK3 was up-regulated and that of miR-326 was down-regulated. CircHIPK3 knockdown inhibited the cell proliferation, invasion, and migration. MiR-326 was the direct target of circHIPK3, and was inversely correlated with circHIPK3 expression. CircHIPK3 overexpression promoted proliferation, migration, invasion, apoptosis resistance, and tumor growth and up-regulated Ki-67 expression, at the same time, the expressions of Bcl-2, N-cadherin, Vimentin were up-regulated, and those of Bax, cleaved Caspase-3 and E-cadherin were inhibited. These above expressions were partially reversed by miR-326 overexpression. Conclusion: CircHIPK3 sponges miR-326 to promote BCa growth and metastasis. The current findings provide a novel therapeutic target for treating BCa.

Cell Plasticity and Prostate Cancer: The Role of Epithelial-Mesenchymal Transition in Tumor Progression, Invasion, Metastasis and Cancer Therapy Resistance

Simple Summary

Although epithelial-to-mesenchymal transition (EMT) is a well-known cellular process involved during normal embryogenesis and wound healing, it also has a dark side; it is a complex process that provides tumor cells with a more aggressive phenotype, facilitating tumor metastasis and even resistance to therapy. This review focuses on the key pathways of EMT in the pathogenesis of prostate cancer and the development of metastases and evasion of currently available treatments.

Abstract

Prostate cancer, the second most common malignancy in men, is characterized by high heterogeneity that poses several therapeutic challenges. Epithelial–mesenchymal transition (EMT) is a dynamic, reversible cellular process which is essential in normal embryonic morphogenesis and wound healing. However, the cellular changes that are induced by EMT suggest that it may also play a central role in tumor progression, invasion, metastasis, and resistance to current therapeutic options. These changes include enhanced motility and loss of cell–cell adhesion that form a more aggressive cellular phenotype. Moreover, the reverse process (MET) is a necessary element of the metastatic tumor process. It is highly probable that this cell plasticity reflects a hybrid state between epithelial and mesenchymal status. In this review, we describe the underlying key mechanisms of the EMT-induced phenotype modulation that contribute to prostate tumor aggressiveness and cancer therapy resistance, in an effort to provide a framework of this complex cellular process.

Overview of all-trans-retinoic acid (ATRA) and its analogues: Structures, activities, and mechanisms in acute promyelocytic leukaemia

All-trans-retinoic acid (ATRA) is effective for preventing cancer and treating skin diseases and acute promyelocytic leukaemia (APL). These pharmacological effects of ATRA are mainly mediated by retinoid X receptors (RXRs) and retinoic acid receptors (RARs). This article provides a comprehensive overview of the clinical progress on and the molecular mechanisms of ATRA in the treatment of APL. ATRA can promote the transcriptional activation of differentiation-related genes and regulate autophagy by inhibiting mTOR, which results in anti-APL effects. In detail, the structures, pharmacological effects, and clinical studies of 68 types of ATRA analogues are described. These compounds have excellent antitumour therapeutic potential and could be used as lead compounds for further development and research.

Apatinib Inhibits Stem Properties and Malignant Biological Behaviors of Breast Cancer Stem Cells by Blocking Wnt/β-catenin Signal Pathway Through Down-regulating LncRNA ROR

BACKGROUND

Cancer stem cells could influence tumor recurrence and metastasis.

OBJECTIVE

To develop a new effective treatment modality targeting breast cancer stem cells (BCSCs), and to explore the role of Apatinib in BCSCs.

METHODS

BCSCs were isolated from MDA-MB-231 cells by immune magnetic beads method. BCSCs were treated with Apatinib, lentiviral plasmids (lncRNA ROR) and iCRT-3 (Wnt pathway inhibitors). Viability, colony numbers, sphere numbers, apoptosis, migration, invasion of BCSCs were detected by MTT, colony formation, tumor sphere, flow cytometry, wound-healing, transwell assays, respectively. The expressions of markers (ABCG2, CD44, CD90, and CD24), epithelial-mesenchymal transition (EMT)-related molecules (E-cadherin, N-cadherin, Vimentin, MMP-2, MMP-9), and Wnt/β-catenin pathway-related proteins (Wnt3a, Wnt5a, β-catenin) in breast cancer stem cells were determined by performing Western blot and qRT-PCR analysis.

RESULTS

Apatinib decreased the viability and colony numbers of BCSCs in a concentration-dependent manner, and it also reduced sphere numbers, suppressed migration, invasion and lncRNA ROR expression, and induced apoptosis of BCSCs. However, these results were partially reversed by lncRNA ROR overexpression. Apatinib suppressed stem property, EMT process and Wnt/β-catenin pathway in BCSCs, which was partially reversed by lncRNA ROR overexpression. Moreover, lncRNA ROR overexpression increased the colony and sphere numbers, and promoted the cell viability, apoptosis inhibition, migration and invasion of BCSCs, but these effects were partially reversed by iCRT-3. LncRNA ROR overexpression increased the stem property, EMT process and Wnt/β-catenin pathway, which were partially counteracted by iCRT-3.

CONCLUSION

Apatinib inhibited stem property and malignant biological behaviors of BCSCs by blocking Wnt/β-catenin signal pathway through down-regulating lncRNA ROR.

Progress in developing MNK inhibitors

The MNKs (mitogen-activated protein kinase-interacting protein kinases) phosphorylate eIF4E (eukaryotic initiation factor 4 E) at serine 209; eIF4E plays an important role in the translation of cytoplasmic mRNAs, all of which possess a 5' 'cap' structure to which eIF4E binds. Elevated levels of eIF4E, p-eIF4E and/or the MNK protein kinases have been found in many types of cancer, including solid tumors and leukemia. MNKs also play a role in metabolic disease. Regulation of the activities of MNKs (MNK1 and MNK2), control the phosphorylation of eIF4E, which in turn has a close relationship with the processes of tumor development, cell migration and invasion, and energy metabolism. MNK knock-out mice display no adverse effects on normal cells or phenotypes suggesting that MNK may be a potentially safe targets for the treatment of various cancers. Several MNK inhibitors or 'degraders' have been identified. Initially, some of the inhibitors were developed from natural products or based on other protein kinase inhibitors which inhibit multiple kinases. Subsequently, more potent and selective inhibitors for MNK1/2 have been designed and synthesized. Currently, three inhibitors (BAY1143269, eFT508 and ETC-206) are in various stages of clinical trials for the treatment of solid cancers or leukemia, either alone or combined with inhibitors of other protein kinase. In this review, we summarize the diverse MNK inhibitors that have been reported in patents and other literature, including those with activities in vitro and/or in vivo.

Carotenoids in Cancer Metastasis-Status Quo and Outlook

Metastasis represents a major obstacle in cancer treatment and the leading cause of cancer-related deaths. Therefore, the identification of compounds targeting the multi-step and complex process of metastasis could improve outcomes in the management of cancer patients. Carotenoids are naturally occurring pigments with a plethora of biological activities. Carotenoids exert a potent anti-cancer capacity in various cancer models in vitro and in vivo, mediated by the modulation of signaling pathways involved in the migration and invasion of cancer cells and metastatic progression, including key regulators of the epithelial-mesenchymal transition and regulatory molecules, such as matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), urokinase plasminogen activator (uPA) and its receptor (uPAR), hypoxia-inducible factor-1α (HIF-1α), and others. Moreover, carotenoids modulate the expression of genes associated with cancer progression and inflammatory processes as key mediators of the complex process involved in metastasis. Nevertheless, due to the predominantly preclinical nature of the known anti-tumor effects of carotenoids, and unclear results from certain carotenoids in specific cancer types and/or specific parts of the population, a precise analysis of the anti-cancer effects of carotenoids is essential. The identification of carotenoids as effective compounds targeting the complex process of cancer progression could improve the outcomes of advanced cancer patients.

MicroRNA‑125a‑5p regulates liver cancer cell growth, migration and invasion and EMT by targeting HAX1

To date, the role of hematopoietic‑substrate‑1‑associated protein X‑1 (HAX1) in liver cancer is rarely studied. The present study explored the role of HAX1 in liver cancer. The association between HAX1 expression and survival of patients with liver cancer was analyzed by a log‑rank test. The target genes for HAX1 was predicted by TargetScan and verified by a dual‑luciferase reporter assay. The protein and mRNA expressions of HAX1 in liver cancer and adjacent non‑cancerous tissues were examined by immunohistochemistry and reverse transcription‑quantitative PCR (RT‑qPCR). The transfection efficiency of HAX1, small interfering RNA against HAX1, microRNA (miR)‑125a mimics, miR‑125a inhibitor, miR‑223 mimics and miR‑223 inhibitor in liver cancer cells was determined by RT‑qPCR. The expression of HAX1, p53, VEGF, epithelial‑to‑mesenchymal transition (EMT)‑related markers (E‑cadherin, N‑cadherin and vimentin) in the cancer cells were determined by western blotting and RT‑qPCR. Cell viability, migration, invasion and colony formation rates were determined by Cell Counting Kot‑8, wound healing, Transwell and colony formation assays, respectively. The results showed that high expression of HAX1 in liver cancer was found relate to poor prognosis in patients with liver cancer, and upregulation of HAX1 expression in liver cancer tissues was related to lower overall survival. miR‑125a‑5p directly binds to HAX1. Upregulation of miR‑125a‑5p expression inhibited cell viability, migration, invasion and colony formation of SK‑Hep1 cells and reduced the expression of HAX1, VEGF, N‑cadherin and vimentin, but increased cell apoptosis and the expression of p53 and E‑cadherin. However, the effects miR‑125a‑5p upregulation were partially reversed by SK‑Hep1 cells with HAX1 overexpression. Downregulated miR‑125a‑5p in SNU‑387 cells produced opposite effects, which was partially reversed by HAX silencing. In conclusion, miR‑125a‑5p suppresses liver cancer growth via targeting HAX1 and concurrently modulating the expression of p53 and VEGF and EMT‑related markers.

Differential expression and inhibitory effects of aquaporins on the development of adenomyosis

Aquaporin 2 (AQP2), AQP5 and AQP8 participate in adenomyosis (AM). Ηowever, the roles of these three molecules in AM have not been fully elucidated. In the present study, Institute of Cancer Research female mice were used to establish a model of AM. Subsequently, the endometrial tissues of the mice were observed by hematoxylin-eosin staining, and AM severity, uterus diameter, uterus index, ovary index and numbers of nodules on the uterine surface were evaluated and counted. In addition, eutopic and ectopic endometrial stromal cells (ESCs) were isolated from eutopic and ectopic endometrial samples derived from patients with AM and were then identified by immunofluorescence. The viability, and migratory and invasive ability of ESCs transfected with small interfering RNA targeting AQP5 (siAQP5) were determined by Cell Counting Κit-8, scratch wound-healing and Transwell assays, respectively. Reverse transcription-quantitative polymerase chain reaction was performed to determine the mRNA expression levels of AQP5, epithelial-mesenchymal transition (EMT)-related genes (E-and N-cadherin), matrix metalloproteinase (MMP)-2 and −9. Protein expression levels of AQP2, AQP5, AQP8, E-, N-cadherin, MMP-2 and −9 were detected by western blotting. AM severity and uterus index were higher, and there were a greater number of nodules on the uterine surface in the AM group compared with the sham group. AQP2, AQP5 and AQP8 proteins were highly expressed in eutopic and ectopic endometrium of the AM group, and AQP5 was more highly expressed than AQP2 or AQP8. In addition, the data showed that Vimentin was positively expressed in ESCs, and that siAQP5 suppressed the mRNA expression levels of AQP5, cell viability, migration, invasion, EMT and MMP-2 and −9 expression in ESCs. In conclusion, AQP2, AQP5 and AQP8 were highly expressed in eutopic and ectopic endometrium. Notably, AQP5 silencing may suppress AM by inhibiting viability, migration, invasion, EMT, and MMP-2 and −9 expression in ESCs.

Phosphorylation of the mRNA cap-binding protein eIF4E and cancer

Dysregulated protein synthesis is frequently involved in oncogenesis and cancer progression. Translation initiation is thought to be the rate-limiting step in protein synthesis, and the mRNA 5' cap-binding protein eukaryotic translation initiation factor 4E (eIF4E) is a pivotal factor that initiates translation. The activities of eIF4E are regulated at multiple levels, one of which is through its phosphorylation at Serine 209 by the mitogen-activated protein kinase-interacting kinases (MNKs, including MNK1 and MNK2). Benefiting from novel mouse genetic tools and pharmacological MNK inhibitors, our understanding of a role for eIF4E phosphorylation in tumor biology and cancer therapy has greatly evolved in recent years. Importantly, recent studies have found that the level of eIF4E phosphorylation is frequently upregulated in a wide variety of human cancer types, and phosphorylation of eIF4E drives a number of important processes in cancer biology, including cell transformation, proliferation, apoptosis, metastasis and angiogenesis. The MNK-eIF4E axis is being assessed as a therapeutic target either alone or in combination with other therapies in different cancer models. As novel MNK inhibitors are being developed, experimental studies bring new hope to cure human cancers that are not responsive to traditional therapies. Herein we review recent progress on our understanding of a mechanistic role for phosphorylation of eIF4E in cancer biology and therapy.

MiR-183-5p Promotes Proliferation, Metastasis and Angiogenesis in Breast Cancer Cells through Negatively Regulating Four and a Half LIM Protein 1

Purpose

Four and a half LIM protein 1 (FHL1) is involved in breast cancer (BC) development, but the regulatory mechanism involved remain unclear. In the present study, we examined the role of FHL1 in BC development.

Methods

The expression of FHL1, miR-183-5p, and miR-96-5p in BC tissues was analyzed using StarBase analysis. FHL1 expression in BC tissues, a normal human breast epithelial cell line, and BC cell lines was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR). The relationship between FHL1 and miR-183-5p/miR-96-5p was analyzed via Pearson's rank correlation, TargetScan, and a dual-luciferase reporter assay. BT549 and MDA-MB-231 cells were transfected with either FHL1 and miR-183-5p mimics, or siFHL1 and a miR-183-5p inhibitor, respectively. The viability, colony number, migration, invasion, and tube length of BT549 and MDA-MB-231 cells were examined using cell counting kit-8, colony formation, wound-healing, Transwell, and tube formation assays, respectively. The levels of FHL1, vascular endothelial growth factor (VEGF), p53, E-cadherin, N-cadherin, and vimentin were quantified using western blotting and qRT-PCR.

Results

FHL1 expression was downregulated in BC tissues and cells, whereas miR-183-5p and miR-96-5p were upregulated in BC tissues (negative correlation with FHL1 expression). FHL1 overexpression inhibited the viability, colony number, migration, and invasion of BC cells and the expression of VEGF, N-cadherin, and vimentin, and increased the expression of FHL1, p53, and E-cadherin in BT549 cells. Furthermore, a miR-183-5p mimic reversed these effects of FHL1 overexpression, whereas FHL1 silencing caused opposite results to those observed in MDA-MB-231 cells; however, this was reversed by a miR-183-5p inhibitor.

Conclusion

Our study suggests that miR-183-5p promotes cell proliferation, metastasis, and angiogenesis by negatively regulating FHL1 in BC.

Unresolved Complexity in the Gene Regulatory Network Underlying EMT

Epithelial to mesenchymal transition (EMT) is the process whereby a polarized epithelial cell ceases to maintain cell-cell contacts, loses expression of characteristic epithelial cell markers, and acquires mesenchymal cell markers and properties such as motility, contractile ability, and invasiveness. A complex process that occurs during development and many disease states, EMT involves a plethora of transcription factors (TFs) and signaling pathways. Whilst great advances have been made in both our understanding of the progressive cell-fate changes during EMT and the gene regulatory networks that drive this process, there are still gaps in our knowledge. Epigenetic modifications are dynamic, chromatin modifying enzymes are vast and varied, transcription factors are pleiotropic, and signaling pathways are multifaceted and rarely act alone. Therefore, it is of great importance that we decipher and understand each intricate step of the process and how these players at different levels crosstalk with each other to successfully orchestrate EMT. A delicate balance and fine-tuned cooperation of gene regulatory mechanisms is required for EMT to occur successfully, and until we resolve the unknowns in this network, we cannot hope to develop effective therapies against diseases that involve aberrant EMT such as cancer. In this review, we focus on data that challenge these unknown entities underlying EMT, starting with EMT stimuli followed by intracellular signaling through to epigenetic mechanisms and chromatin remodeling.

Deeping in the Role of the MAP-Kinases Interacting Kinases (MNKs) in Cancer

The mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs) are involved in oncogenic transformation and can promote metastasis and tumor progression. In human cells, there are four MNKs isoforms (MNK1a/b and MNK2a/b), derived from two genes by alternative splicing. These kinases play an important role controlling the expression of specific proteins involved in cell cycle, cell survival and cell motility via eukaryotic initiation factor 4E (eIF4E) regulation, but also through other substrates such as heterogeneous nuclear ribonucleoprotein A1, polypyrimidine tract-binding protein-associated splicing factor and Sprouty 2. In this review, we provide an overview of the role of MNK in human cancers, describing the studies conducted to date to elucidate the mechanism involved in the action of MNKs, as well as the development of MNK inhibitors in different hematological cancers and solid tumors.

MiR-532-5p Suppresses Migration and Invasion of Lung Cancer Cells Through Inhibiting CCR4

Background: Studies showed that miR-532-5p suppresses proliferation and induces apoptosis of lung cancer (LC) cells; its role in LC is not fully understood. Therefore, this research aimed to reveal the effect and mechanism of miR-532-5p on migration and invasion of LC cells. Materials and Methods: The transfection efficiencies of miR-532-5p mimic, inhibitor, and overexpressed CCR4 were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The relationships between miR-532-5p and CCR4 in A549 and SBC-5 cells were predicted by targetScan and verified by dual-luciferase reporter assay, Western blot, and qRT-PCR. Migration and invasion of cells transfected with miR-532-5p mimic, inhibitor, and CCR4 were determined by scratch test and transwell assay, respectively. The levels of epithelial-to-mesenchymal transition (EMT)-related proteins (E-cadherin (E-Cad)), N-catenin (N-Cad), and vimentin) in cells were measured by Western blot. Results: MiR-532-5p mimic suppressed migration and invasion, while miR-532-5p inhibitor promoted migration and invasion of cells. CCR4 was a downstream target of miR-532-5p and both its protein and mRNA expressions were inhibited by miR-532-5p mimic, but promoted by miR-532-5p inhibitor. CCR4 promoted migration, invasion, and EMT process, and such effects of CCR4 were reversed by miR-532-5p mimic. Conclusion: MiR-532-5p functioned as a cancer suppressor by negatively regulating CCR4 in LC cells, pointing to a potential protective mechanism of miR-532-5p to LC patients.

Androgen receptor variant-driven prostate cancer II: advances in laboratory investigations

Background:

The androgen receptor (AR) is a key prostate cancer drug target. Suppression of AR signaling mediated by the full-length AR (AR-FL) is the therapeutic goal of all existing AR-directed therapies. AR-targeting agents impart therapeutic benefit, but lead to AR aberrations that underlie disease progression and therapeutic resistance. Among the AR aberrations specific to castration-resistant prostate cancer (CRPC), AR variants (AR-Vs) have emerged as important indicators of disease progression and therapeutic resistance.

Methods:

We conducted a systemic review of the literature focusing on recent laboratory studies on AR-Vs following our last review article published in 2016. Topics ranged from measurement and detection, molecular origin, regulation, genomic function, and preclinical therapeutic targeting of AR-Vs. We provide expert opinions and perspectives on these topics.

Results:

Transcript sequences for 22 AR-Vs have been reported in the literature. Different AR-Vs may arise through different mechanisms, and can be regulated by splicing factors and dictated by genomic rearrangements, but a low-androgen environment is a prerequisite for generation of AR-Vs. The unique transcript structures allowed development of in-situ and in-solution measurement and detection methods, including mRNA and protein detection, in both tissue and blood specimens. AR variant-7 (AR-V7) remains the main measurement target and the most extensively characterized AR-V. Although AR-V7 co-exists with AR-FL, genomic functions mediated by AR-V7 do not require the presence of AR-FL. The distinct cistromes and transcriptional programs directed by AR-V7 and their co-regulators are consistent with genomic features of progressive disease in a low-androgen environment. Preclinical development of AR-V-directed agents currently focuses on suppression of mRNA expression and protein degradation as well as targeting of the amino-terminal domain.

Conclusions:

Current literature continues to support AR-Vs as biomarkers and therapeutic targets in prostate cancer. Laboratory investigations reveal both challenges and opportunities in targeting AR-Vs to overcome resistance to current AR-directed therapies.

Galeterone and The Next Generation Galeterone Analogs, VNPP414 and VNPP433-3β Exert Potent Therapeutic Effects in Castration-/Drug-Resistant Prostate Cancer Preclinical Models In Vitro and In Vivo

These studies compared the efficacies of our clinical agent galeterone (Gal) and the FDA-approved prostate cancer drug, enzalutamide (ENZ) with two lead next generation galeterone analogs (NGGAs), VNPP414 and VNPP433-3β, using prostate cancer (PC) in vitro and in vivo models. Antitumor activities of orally administered agents were also assessed in CWR22Rv1 tumor-bearing mice. We demonstrated that Gal and NGGAs degraded AR/AR-V7 and Mnk1/2; blocked cell cycle progression and proliferation of human PC cells; induced apoptosis; inhibited cell migration, invasion, and putative stem cell markers; and reversed the expression of epithelial-to-mesenchymal transition (EMT). In addition, Gal/NGGAs (alone or in combination) also inhibited the growth of ENZ-, docetaxel-, and mitoxantrone-resistant human PC cell lines. The NGGAs exhibited improved pharmacokinetic profiles over Gal in mice. Importantly, in vivo testing showed that VNPP433-3β (at 7.53-fold lower equimolar dose than Gal) markedly suppressed (84% vs. Gal, 47%; p < 0.01) the growth of castration-resistant PC (CRPC) CWR22Rv1 xenograft tumors, with no apparent host toxicity. ENZ was ineffective in this CRPC xenograft model. In summary, our findings show that targeting AR/AR-V7 and Mnk1/2 for degradation represents an effective therapeutic strategy for PC/CRPC treatment and supports further development of VNPP433-3β towards clinical investigation.

Positive Correlative over-Expression between eIF4E and Snail in Nasopharyngeal Carcinoma Promotes its Metastasis and Resistance to Cisplatin

EIF4E is the rate-limiting factor in the mRNA translation of specific set of oncogenes. Snail is the core transcription factor of epithelial-mesenchymal transition (EMT), a key step of cancer metastasis. The connection between the two oncoproteins has not been well established in the human cancer tissues and in nasopharyngeal carcinoma (NPC). Here we showed that the positive correlative over-expression was seen between eIF4E and Snail in NPC tissues, and the expression was significantly higher in the metastatic NPC than in the un-metastatic NPC. In NPC cells, eIF4E knockdown significantly reduced Snail mRNA and protein levels, increased the mRNA level of E-cad (a direct downstream gene of Snail and a negative EMT marker), attenuated the invasive ability of the cells, and sensitized the cells to cisplatin in invasion. In contrast, enforced the expression of eIF4E significantly increased Snail mRNA and protein levels, and promoted the invasive ability in NPC cells. Under the condition of the high eIF4E expression, Snail knockdown significantly increased E-cad mRNA level and weaken the invasive ability of NPC cells. Finally, eIF4E directly bound Snail mRNA for translation initiation displayed by the RIP assay. Therefore, the results firstly suggested that eIF4E enhanced the Snail expression in both transcription and translation manner in human cancer tissues and targeting the eIF4E/Snail axis might intervene with the EMT and metastasis of NPC. This finding provided a new clue for further understanding the metastatic mechanism of human cancers and for preventing and treating NPC metastasis.

Epithelial mesenchymal transition and resistance in endocrine-related cancers

Epithelial to mesencyhmal transition (EMT) has a central role in tumor metastasis and progression. EMT is regulated by several growth factors and pro-inflammatory cytokines. The most important role in this regulation could be attributed to transforming growth factor-β (TGF-β). In breast cancer, TGF-β effect on EMT could be potentiated by Fos-related antigen, oncogene HER2, epidermal growth factor, or mitogen-activated protein kinase kinase 5 - extracellular-regulated kinase signaling. Several microRNAs in breast cancer have a considerable role either in potentiation or in suppression of EMT thus acting as oncogenic or tumor suppressive modulators. At present, possibilities to target EMT are discussed but the results of clinical translation are still limited. In prostate cancer, many cellular events are regulated by androgenic hormones. Different experimental results on androgenic stimulation or inhibition of EMT have been reported in the literature. Thus, a possibility that androgen ablation therapy leads to EMT thus facilitating tumor progression has to be discussed. Novel therapy agents, such as the anti-diabetic drug metformin or selective estrogen receptor modulator ormeloxifene were used in pre-clinical studies to inhibit EMT in prostate cancer. Taken together, the results of pre-clinical and clinical studies in breast cancer may be helpful in the process of drug development and identify potential risk during the early stage of that process.

Restoring E-cadherin Expression by Natural Compounds for Anticancer Therapies in Genital and Urinary Cancers

E-cadherin plays a pivotal role in cancer progression, including the epithelial-mesenchymal transition (EMT) process and tumor metastasis. Loss of E-cadherin contributes to enhanced invasion and metastasis in human cancers. Therefore, restoring E-cadherin could be a potential approach for cancer therapy. Multiple natural compounds have been shown to possess anti-tumor activities through the regulation of key molecules in signaling pathways, including E-cadherin. In this review, we describe the numerous compounds that restore the expression of E-cadherin in genital and urinary malignancies. We further discuss the potential anti-tumor molecular mechanisms of these agents as the activators of E-cadherin in genital and urinary cancers. Although these compounds exhibit their potential to inhibit the development and progression of cancers, there are several challenges to developing them as therapeutic drugs for cancer patients. Poor bioavailability in vivo is the main disadvantage of these compounds. Modification of compound structures has produced actual improvements in bioavailability. Nanoparticle-based delivery systems could be useful to deliver the agents to targeted organs. These compounds could be new promising therapeutic agents for the treatment of human genital and urinary cancers. Further investigations are required to determine the safety and side effects of natural compounds using animal models prior to clinical trials.

The Novel Mnk1/2 Degrader and Apoptosis Inducer VNLG-152 Potently Inhibits TNBC Tumor Growth and Metastasis

Currently, there are no effective therapies for patients with triple-negative breast cancer (TNBC), an aggressive and highly metastatic disease. Activation of eukaryotic initiation factor 4E (eIF4E) by mitogen-activated protein kinase (MAPK)-interacting kinases 1 and 2 (Mnk1/2) play a critical role in the development, progression and metastasis of TNBC. Herein, we undertook a comprehensive study to evaluate the activity of a first-in-class Mnk1/2 protein degraders, racemic VNLG-152R and its two enantiomers (VNLG-152E1 and VNLG-152E2) in in vitro and in vivo models of TNBC. These studies enabled us to identify racemic VNLG-152R as the most efficacious Mnk1/2 degrader, superior to its pure enantiomers. By targeting Mnk1/2 protein degradation (activity), VNLG-152R potently inhibited both Mnk-eIF4E and mTORC1 signaling pathways and strongly regulated downstream factors involved in cell cycle regulation, apoptosis, pro-inflammatory cytokines/chemokines secretion, epithelial-mesenchymal transition (EMT) and metastasis. Most importantly, orally bioavailable VNLG-152R exhibited remarkable antitumor (91 to 100% growth inhibition) and antimetastatic (~80% inhibition) activities against cell line and patient-derived TNBC xenograft models, with no apparent host toxicity. Collectively, these studies demonstrate that targeting Mnk-eIF4E/mTORC1 signaling with a potent Mnk1/2 degrader, VNLG-152R, is a novel therapeutic strategy that can be developed as monotherapy for the effective treatment of patients with primary/metastatic TNBC.