Inhibition of CBP/β-catenin and porcupine attenuates Wnt signaling and induces apoptosis in head and neck carcinoma cells

Unraveling Cancer's Wnt Signaling: Dynamic Control through Protein Kinase Regulation

Since the initial identification of oncogenic Wnt in mice and Drosophila, the Wnt signaling pathway has been subjected to thorough and extensive investigation. Persistent activation of Wnt signaling exerts diverse cancer characteristics, encompassing tumor initiation, tumor growth, cell senescence, cell death, differentiation, and metastasis. Here we review the principal signaling mechanisms and the regulatory influence of pathway-intrinsic and extrinsic kinases on cancer progression. Additionally, we underscore the divergences and intricate interplays of the canonical and non-canonical Wnt signaling pathways and their critical influence in cancer pathophysiology, exhibiting both growth-promoting and growth-suppressing roles across diverse cancer types.

Mature neurons from iPSCs unveil neurodegeneration-related pathways in mucopolysaccharidosis type II: GSK-3β inhibition for therapeutic potential

Mucopolysaccharidosis (MPS) type II is caused by a deficiency of iduronate-2-sulfatase and is characterized by the accumulation of glycosaminoglycans (GAGs). Without effective therapy, the severe form of MPS II causes progressive neurodegeneration and death. This study generated multiple clones of induced pluripotent stem cells (iPSCs) and their isogenic controls (ISO) from four patients with MPS II neurodegeneration. MPS II-iPSCs were successfully differentiated into cortical neurons with characteristic biochemical and cellular phenotypes, including axonal beadings positive for phosphorylated tau, and unique electrophysiological abnormalities, which were mostly rescued in ISO-iPSC-derived neurons. RNA sequencing analysis uncovered dysregulation in three major signaling pathways, including Wnt/β-catenin, p38 MAP kinase, and calcium pathways, in mature MPS II neurons. Further mechanistic characterization indicated that the dysregulation in calcium signaling led to an elevated intracellular calcium level, which might be linked to compromised survival of neurons. Based on these dysregulated pathways, several related chemicals and drugs were tested using this mature MPS II neuron-based platform and a small-molecule glycogen synthase kinase-3β inhibitor was found to significantly rescue neuronal survival, neurite morphology, and electrophysiological abnormalities in MPS II neurons. Our results underscore that the MPS II-iPSC-based platform significantly contributes to unraveling the mechanisms underlying the degeneration and death of MPS II neurons and assessing potential drug candidates. Furthermore, the study revealed that targeting the specific dysregulation of signaling pathways downstream of GAG accumulation in MPS II neurons with a well-characterized drug could potentially ameliorate neuronal degeneration.

Identification and In Vivo Validation of Unique Anti-Oncogenic Mechanisms Involving Protein Kinase Signaling and Autophagy Mediated by the Investigational Agent PV-10

PV-10 is a 10% formulation of rose bengal sodium that has potent immunotherapeutic and anti-cancer activity against various tumors, including metastatic melanoma and refractory neuroblastoma. Currently, PV-10 is undergoing clinical testing for refractory metastatic neuroendocrine cancer and melanomas. However, preclinical investigation of PV-10 activity and its mechanisms against phenotypically and molecularly diverse adult solid tumors had not been conducted. In a panel of human cell lines derived from breast, colorectal, head and neck, and testicular cancers, we demonstrated that PV-10 induces cytotoxicity by apoptotic and autophagic pathways involving caspase-mediated PARP cleavage, downregulation of SQSTM1/p62, and upregulation of beclin-1. Treatment with PV-10 also consistently reduced phosphorylation of WNK1, which has been implicated in cancer cell migration and autophagy inhibition. By wound healing assay, PV-10 treatment inhibited the migration of cancer cells. Finally, significant inhibition of tumor growth was also noted in tumor-bearing mice treated with PV-10 by intralesional or systemic administration. In addition to known PV-10-mediated tumor-specific cytotoxic effects, we identified the mechanisms of PV-10 and provide new insights into its effect on autophagy and metastasis. Our data provide essential mechanism-based evidence and biomarkers of activity to formulate clinical studies of PV-10 in the future.

The β-catenin C terminus links Wnt and sphingosine-1-phosphate signaling pathways to promote vascular remodeling and atherosclerosis

Canonical Wnt and sphingosine-1-phosphate (S1P) signaling pathways are highly conserved systems that contribute to normal vertebrate development, with key consequences for immune, nervous, and cardiovascular system function; despite these functional overlaps, little is known about Wnt/β-catenin-S1P cross-talk. In the vascular system, both Wnt/β-catenin and S1P signals affect vessel maturation, stability, and barrier function, but information regarding their potential coordination is scant. We report an instance of functional interaction between the two pathways, including evidence that S1P receptor 1 (S1PR1) is a transcriptional target of β-catenin. By studying vascular smooth muscle cells and arterial injury response, we find a specific requirement for the β-catenin carboxyl terminus, which acts to induce S1PR1, and show that this interaction is essential for vascular remodeling. We also report that pharmacological inhibition of the β-catenin carboxyl terminus reduces S1PR1 expression, neointima formation, and atherosclerosis. These findings provide mechanistic understanding of how Wnt/β-catenin and S1P systems collaborate during vascular remodeling and inform strategies for therapeutic manipulation.

The acetyltransferase BmCBP changes the acetylation modification of BmSP3 and affects its protein expression in silkworm, Bombyx mori

BACKGROUND

Protein acetylation is an important post-translational modification (PTM) that widely exists in organisms. As a reversible PTM, acetylation modification can regulate the function of proteins with high efficiency. In the previous study, the acetylation sites of silkworm proteins were identified on a large scale by nano-HPLC/MS/MS (nanoscale high performance liquid chromatography-tandem secondary mass spectrometry), and a total of 11 acetylation sites were discovered on Bombyx mori nutrient-storage protein SP3 (BmSP3). The purpose of this study was to investigate the effect of acetylation level on BmSP3.

METHODS AND RESULTS

In this study, the acetylation of BmSP3 was further verified by immunoprecipitation (IP) and Western blotting. Then, it was confirmed that acetylation could up-regulate the expression of BmSP3 by improving its protein stability in BmN cells. Co-IP and RNAi experiments showed acetyltransferase BmCBP could bind to BmSP3 and catalyze its acetylation modification, then regulate the expression of BmSP3. Furthermore, the knock-down of BmCBP could improve the ubiquitination level of BmSP3. Both acetylation and ubiquitination occur on the side chain of lysine residues, therefore, we speculated that the acetylation of BmSP3 catalyzed by BmCBP could competitively inhibit its ubiquitination modification and improve its protein stability by inhibiting ubiquitin-mediated proteasome degradation pathway, and thereby increase the expression and intracellular accumulation.

CONCLUSIONS

BmCBP catalyzes the acetylation of BmSP3 and may improve the stability of BmSP3 by competitive ubiquitination. This conclusion provides a new functional basis for the extensive involvement of acetylation in the regulation of nutrient storage and utilization in silkworm, Bombyx mori.

Advantages of the Combinatorial Molecular Targeted Therapy of Head and Neck Cancer-A Step before Anakoinosis-Based Personalized Treatment

The molecular initiators of Head and Heck Squamous Cell Carcinoma (HNSCC) are complex. Human Papillomavirus (HPV) infection is linked to an increasing number of HNSCC cases, but HPV-positive tumors generally have a good prognosis. External factors that promote the development of HPV-negative HNSCC include tobacco use, excessive alcohol consumption, and proinflammatory poor oral hygiene. On a molecular level, several events, including the well-known overexpression of epidermal growth factor receptors (EGFR) and related downstream signaling pathways, contribute to the development of HNSCC. Conventional chemotherapy is insufficient for many patients. Thus, molecular-based therapy for HNSCC offers patients a better chance at a cure. The first molecular target for therapy of HNSCC was EGFR, inhibited by monoclonal antibody cetuximab, but its use in monotherapy is insufficient and induces resistance. This article describes attempts at combinatorial molecular targeted therapy of HNSCC based on several molecular targets and exemplary drugs/drug candidates. The new concept of anakoinosis-based therapy, which means treatment that targets the intercellular and intracellular communication of cancer cells, is thought to be the way to improve the clinical outcome for HNSCC patients. The identification of a link between molecular targeted therapy and anakoinosis raises the potential for further progress in HPV-negative HNSCC therapy.

Combinations of PRI-724 Wnt/β-Catenin Pathway Inhibitor with Vismodegib, Erlotinib, or HS-173 Synergistically Inhibit Head and Neck Squamous Cancer Cells

The Wnt/β-catenin, EGFR, and PI3K pathways frequently undergo upregulation in head and neck squamous carcinoma (HNSCC) cells. Moreover, the Wnt/β-catenin pathway together with Hedgehog (Hh) signaling regulate the activity of cancer stem cells (CSCs). The aim of this study was to investigate the effects of the combinatorial use of the Wnt/β-catenin and Hh pathway inhibitors on viability, cell cycle progression, apoptosis induction, cell migration, and expression of CSC markers in tongue (CAL 27) and hypopharynx (FaDu) cancer cells. Co-inhibition of Wnt signaling with EGFR or PI3K pathways was additionally tested. The cells were treated with selective inhibitors of signaling pathways: Wnt/β-catenin (PRI-724), Hh (vismodegib), EGFR (erlotinib), and PI3K (HS-173). Cell viability was evaluated by the resazurin assay. Cell cycle progression and apoptosis induction were tested by flow cytometric analysis after staining with propidium iodide and Annexin V, respectively. Cell migration was detected by the scratch assay and CSC marker expression by the R-T PCR method. Mixtures of PRI-724 and vismodegib affected cell cycle distribution, greatly reduced cell migration, and downregulated the transcript level of CSC markers, especially POU5F1 encoding OCT4. Combinations of PRI-724 with erlotinib or HS-173 were more potent in inducing apoptosis.

Short peptide domains of the Wnt inhibitor sFRP4 target ovarian cancer stem cells by neutralizing the Wnt β-catenin pathway, disrupting the interaction between β-catenin and CD24 and suppressing autophagy

AIMS

One of the hallmarks of cancer stem cells (CSC) is hyperactive Wnt β-catenin signaling due to the decreased presence of Wnt antagonists such as secreted frizzled related protein 4 (SFRP4). Cysteine-rich domain (CRD) and netrin-like domain (NLD) are the two functional domains of SFRP4 having anti-tumor properties. In this study, we have explored the effectiveness of short micropeptides SC-301 (from CRD) and SC-401 (from NLD) on CSC properties, EMT, apoptosis and autophagy in ovarian CSCs enriched from PA-1 and SKOV-3 cell lines.

MAIN METHODS

Gene expression analysis, Western blot and immunocytochemistry were performed on ovarian CSCs to evaluate the inhibitory potential of micropeptides to various CSC associated oncogenic properties. Co-immunoprecipitation was performed to detect the binding of CD24 to β-catenin protein complex. CYTO-ID Autophagy Detection Kit 2.0 was used to monitor autophagic flux in peptide treated CSCs.

KEY FINDINGS

It is clearly seen that the micropeptides derived from both the domains inhibit Wnt pathway, initiate apoptosis, inhibit migration and chemosensitize CSCs. Specifically, CD24, a defining marker of ovarian CSC was suppressed by peptide treatment. Notably, interaction between CD24 and β-catenin was disrupted upon peptide treatment. SFRP4 peptide treatment also suppressed the autophagic process which is crucial for CSC survival.

SIGNIFICANCE

The study demonstrated that although both peptides have inhibitory effects, SC-401 was emphatically more effective in targeting CSC properties and down regulating the Wnt β-catenin machinery.

The role of Evi/Wntless in exporting Wnt proteins

Intercellular communication by Wnt proteins governs many essential processes during development, tissue homeostasis and disease in all metazoans. Many context-dependent effects are initiated in the Wnt-producing cells and depend on the export of lipidated Wnt proteins. Although much focus has been on understanding intracellular Wnt signal transduction, the cellular machinery responsible for Wnt secretion became better understood only recently. After lipid modification by the acyl-transferase Porcupine, Wnt proteins bind their dedicated cargo protein Evi/Wntless for transport and secretion. Evi/Wntless and Porcupine are conserved transmembrane proteins, and their 3D structures were recently determined. In this Review, we summarise studies and structural data highlighting how Wnts are transported from the ER to the plasma membrane, and the role of SNX3-retromer during the recycling of its cargo receptor Evi/Wntless. We also describe the regulation of Wnt export through a post-translational mechanism and review the importance of Wnt secretion for organ development and cancer, and as a future biomarker.

Inhibition of beta-catenin shows therapeutic potential in head and neck squamous cell carcinoma in vitro

Beta-catenin is known to be a vital component of the canonical Wnt signaling cascade, involved in the carcinogenesis of different solid tumors. We aimed to evaluate the effects of Beta-catenin inhibition in head and neck squamous cell carcinoma (HNSCC) in vitro. The small molecular compound MSAB was used to inhibit Wnt/Beta-catenin signaling in a human papillomavirus (HPV)-positive and HPV-negative cell line and its effects on cell proliferation, migration, colony formation, apoptosis, as well as radiosensitizing properties were assessed. Significant antineoplastic effects were observed in both cell lines. Interestingly, stronger anti-neoplastic and radiosensitizing effects were observed in the HPV-negative cell line, whereas stronger anti-migratory potential was detected in HPV-positive HNSCC cells. In conclusion, our findings suggest MSAB as a potential therapeutic agent for HNSCC. Further studies are warranted to unravel the mechanistic background of our findings.

From Basic Science to Clinical Practice: The Role of Cancerous Inhibitor of Protein Phosphatase 2A (CIP2A)/p90 in Cancer

Cancerous inhibitor of protein phosphatase 2A (CIP2A), initially reported as a tumor-associated antigen (known as p90), is highly expressed in most solid and hematological tumors. The interaction of CIP2A/p90, protein phosphatase 2A (PP2A), and c-Myc can hinder the function of PP2A toward c-Myc S62 induction, thus stabilizing c-Myc protein, which represents a potential role of CIP2A/p90 in tumorigeneses such as cell proliferation, invasion, and migration, as well as cancer drug resistance. The signaling pathways and regulation networks of CIP2A/p90 are complex and not yet fully understood. Many previous studies have also demonstrated that CIP2A/p90 can be used as a potential therapeutic cancer target. In addition, the autoantibody against CIP2A/p90 in sera may be used as a promising biomarker in the diagnosis of certain types of cancer. In this Review, we focus on recent advances relating to CIP2A/p90 and their implications for future research.

Inhibition of beta-catenin shows therapeutic potential in head and neck squamous cell carcinoma in vitro

Beta-catenin is known to be a vital component of the canonical Wnt signaling cascade, involved in the carcinogenesis of different solid tumors. We aimed to evaluate the effects of Beta-catenin inhibition in head and neck squamous cell carcinoma (HNSCC) in vitro. The small molecular compound MSAB was used to inhibit Wnt/Beta-catenin signaling in a human papillomavirus (HPV)-positive and HPV-negative cell line and its effects on cell proliferation, migration, colony formation, apoptosis, as well as radiosensitizing properties were assessed. Significant antineoplastic effects were observed in both cell lines. Interestingly, stronger anti-neoplastic and radiosensitizing effects were observed in the HPV-negative cell line, whereas stronger anti-migratory potential was detected in HPV-positive HNSCC cells. In conclusion, our findings suggest MSAB as a potential therapeutic agent for HNSCC. Further studies are warranted to unravel the mechanistic background of our findings.

Porcn as a novel therapeutic target in cancer therapy: A review

Wingless-related integration site (Wnt) signaling is one of the main oncogenic pathways in different malignancies. Therefore, targeting this pathway has been considered an exciting strategy in cancer treatment. Porcn is among the central enzymes in this pathway that has recently been considered for cancer-targeted therapy. As a membrane-bound O-acyltransferase, Porcn plays a critical role in wnt ligand palmitoylation and its subsequent secretion. In addition to Porcn's role in stem cell signaling and differentiation, recent findings have shown its role in developing and progressing colorectal, pancreatic, liver, head, and neck cancers. Developed small molecule inhibitors have also opened a promising window toward cancer treatment strategies. In this review, the structure and biological role of Porcn in different cancer-related signaling pathways and inhibitors used for inhibiting this enzyme are discussed.

The Emerging Significance of Histone Lysine Demethylases as Prognostic Markers and Therapeutic Targets in Head and Neck Cancers

Epigenetic aberrations, associated with altered DNA methylation profiles and global changes in the level of histone modifications, are commonly detected in head and neck squamous cell carcinomas (HNSCC). Recently, histone lysine demethylases have been implicated in the pathogenesis of HNSCC and emerged as potential molecular targets. Histone lysine demethylases (KDMs) catalyze the removal of methyl groups from lysine residues in histones. By affecting the methylation of H3K4, H3K9, H3K27, or H3K36, these enzymes take part in transcriptional regulation, which may result in changes in the level of expression of tumor suppressor genes and protooncogenes. KDMs are involved in many biological processes, including cell cycle control, senescence, DNA damage response, and heterochromatin formation. They are also important regulators of pluripotency. The overexpression of most KDMs has been observed in HNSCC, and their inhibition affects cell proliferation, apoptosis, cell motility, invasiveness, and stemness. Of all KDMs, KDM1, KDM4, KDM5, and KDM6 proteins are currently regarded as the most promising prognostic and therapeutic targets in head and neck cancers. The aim of this review is to present up-to-date knowledge on the significance of histone lysine demethylases in head and neck carcinogenesis and to discuss the possibility of using them as prognostic markers and pharmacological targets in patients’ treatment.

The Wnt Signaling Pathway Inhibitors Improve the Therapeutic Activity of Glycolysis Modulators against Tongue Cancer Cells

Excessive glucose metabolism and disruptions in Wnt signaling are important molecular changes present in oral cancer cells. The aim of this study was to evaluate the effects of the combinatorial use of glycolysis and Wnt signaling inhibitors on viability, cytotoxicity, apoptosis induction, cell cycle distribution and the glycolytic activity of tongue carcinoma cells. CAL 27, SCC-25 and BICR 22 tongue cancer cell lines were used. Cells were treated with inhibitors of glycolysis (2-deoxyglucose and lonidamine) and of Wnt signaling (PRI-724 and IWP-O1). The effects of the compounds on cell viability and cytotoxicity were evaluated with MTS and CellTox Green tests, respectively. Apoptosis was evaluated by MitoPotential Dye staining and cell cycle distribution by staining with propidium iodide, followed by flow cytometric cell analysis. Glucose and lactate concentrations in a culture medium were evaluated luminometrically. Combinations of 2-deoxyglucose and lonidamine with Wnt pathway inhibitors were similarly effective in the impairment of oral cancer cells’ survival. However, the inhibition of the canonical Wnt pathway by PRI-724 was more beneficial, based on the glycolytic activity of the cells. The results point to the therapeutic potential of the combination of low concentrations of glycolytic modulators with Wnt pathway inhibitors in oral cancer cells.

Oral Cancer Stem Cells: Therapeutic Implications and Challenges

Head and neck squamous cell carcinoma (HNSCC) is currently one of the 10 most common malignancies worldwide, characterized by a biologically highly diverse group of tumors with non-specific biomarkers and poor prognosis. The incidence rate of HNSCC varies widely throughout the world, with an evident prevalence in developing countries such as those in Southeast Asia and Southern Africa. Tumor relapse and metastasis following traditional treatment remain major clinical problems in oral cancer management. Current evidence suggests that therapeutic resistance and metastasis of cancer are mainly driven by a unique subpopulation of tumor cells, termed cancer stem cells (CSCs), or cancer-initiating cells (CICs), which are characterized by their capacity for self-renewal, maintenance of stemness and increased tumorigenicity. Thus, more understanding of the molecular mechanisms of CSCs and their behavior may help in developing effective therapeutic interventions that inhibit tumor growth and progression. This review provides an overview of the main signaling cascades in CSCs that drive tumor repropagation and metastasis in oral cancer, with a focus on squamous cell carcinoma. Other oral non-SCC tumors, including melanoma and malignant salivary gland tumors, will also be considered. In addition, this review discusses some of the CSC-targeted therapeutic strategies that have been employed to combat disease progression, and the challenges of targeting CSCs, with the aim of improving the clinical outcomes for patients with oral malignancies. Targeting of CSCs in head and neck cancer (HNC) represents a promising approach to improve disease outcome. Some CSC-targeted therapies have already been proven to be successful in pre-clinical studies and they are now being tested in clinical trials, mainly in combination with conventional treatment regimens. However, some studies revealed that CSCs may not be the only players that control disease relapse and progression of HNC. Further, clinical research studying a combination of therapies targeted against head and neck CSCs may provide significant advances.

Wnt/β-catenin signaling in cancers and targeted therapies

Wnt/β-catenin signaling has been broadly implicated in human cancers and experimental cancer models of animals. Aberrant activation of Wnt/β-catenin signaling is tightly linked with the increment of prevalence, advancement of malignant progression, development of poor prognostics, and even ascendence of the cancer-associated mortality. Early experimental investigations have proposed the theoretical potential that efficient repression of this signaling might provide promising therapeutic choices in managing various types of cancers. Up to date, many therapies targeting Wnt/β-catenin signaling in cancers have been developed, which is assumed to endow clinicians with new opportunities of developing more satisfactory and precise remedies for cancer patients with aberrant Wnt/β-catenin signaling. However, current facts indicate that the clinical translations of Wnt/β-catenin signaling-dependent targeted therapies have faced un-neglectable crises and challenges. Therefore, in this study, we systematically reviewed the most updated knowledge of Wnt/β-catenin signaling in cancers and relatively targeted therapies to generate a clearer and more accurate awareness of both the developmental stage and underlying limitations of Wnt/β-catenin-targeted therapies in cancers. Insights of this study will help readers better understand the roles of Wnt/β-catenin signaling in cancers and provide insights to acknowledge the current opportunities and challenges of targeting this signaling in cancers.

WDR5 promotes the tumorigenesis of oral squamous cell carcinoma via CARM1/β-catenin axis

Oral squamous cell carcinoma (OSCC) is a malignancy all over the world. WD repeat domain 5 (WDR5) is involved in cancer progression. In addition, it was reported that WDR5 is upregulated in head and neck cancer, while its role in OSCC is unknown. First, the expression of WDR5 in oral cancer tissues and cells was examined by qRT-PCR, IHF and western blot. CCK-8 assay was performed to test the cell viability. Cell migration was assessed by transwell assay. Knocking down WDR5 or CARM1 in oral cancer cells to detect its function on cancer growth, WDR5 and CARM1 were significantly upregulated in OSCC. Silencing WDR5 suppressed OSCC cell viability and migration. CARM1 level in OSCC cells was significantly inhibited by WDR5 downregulation, and CARM1 elevation could rescue the effect of WDR5 knockdown on tumorigenesis of OSCC. Moreover, silencing of WDR5 notably inactivated β-catenin signaling pathway, while this phenomenon was restored by CARM1 overexpression. Silencing of WDR5 attenuated the tumorigenesis of OSCC via CARM1/β-catenin axis. Thus, WDR5 might be a target for OSCC treatment.

The inhibitors of KDM4 and KDM6 histone lysine demethylases enhance the anti-growth effects of erlotinib and HS-173 in head and neck cancer cells

Novel therapeutics are required to improve treatment outcomes in head and neck squamous cell carcinoma (HNSCC) patients. Histone lysine demethylases (KDM) have emerged recently as new potential drug targets for HNSCC therapy. They might also potentiate the action of the inhibitors of EGFR and PI3K signaling pathways. This study aimed at evaluating the anti-cancer effects of KDM4 (ML324) and KDM6 (GSK-J4) inhibitors and their combinations with EGFR (erlotinib) and PI3K (HS-173) inhibitors in HNSCC cells. The effect of the inhibitors on the viability of CAL27 and FaDu cells was evaluated using resazurin assay. The effect of the chemicals on cell cycle and apoptosis was assessed using propidium iodide and Annexin V staining, respectively. The effect of the compounds on gene expression was determined using qPCR and Western blot. The changes in cell cycle distribution upon treatment with the compounds were small to moderate, with the exception of erlotinib, which induced G1 arrest. However, all the compounds and their combinations induced apoptosis in both cell lines. These effects were associated with changes in the level of expression of CDKN1A, CCND1 and BIRC5. The inhibition of KDM4 and KDM6 using ML324 and GSK-J4, respectively, can be regarded as a novel therapeutic strategy in HNSCC.

The combinatorial inhibition of Wnt signaling and Akt kinase is beneficial for reducing the survival and glycolytic activity of tongue cancer cells

BACKGROUND

Wnt signaling is important in the development of head and neck squamous cell carcinomas (HNSCC); however, Wnt pathway inhibitors lack satisfactory potency when used in monotherapy. The aim of this study was to assess the effects of the combinations of Wnt-signaling inhibitors and the inhibitor of Akt kinase on the survival and glycolytic activity of tongue carcinoma cells.

METHODS

CAL27, SCC-25, and BICR22 tongue cancer cell lines were used. Cells were treated with Wnt signaling (PRI-724 and IWP-O1) and Akt-kinase inhibitors. The effect of the chemicals on cell viability and cytotoxicity were evaluated by MTS and CellTox Green assays, respectively. Cell cycle distribution was analyzed cytometrically after propidium iodide staining. Annexin V binding to externalized phosphatidylserine and analysis of mitochondrial potential allowed the assessment of apoptosis. Glucose uptake and lactate release were evaluated luminometrically. Additionally, the viability of cells in spheroids was analyzed based on ATP content.

RESULTS

The Akt-kinase inhibitor showed significant cytotoxicity toward primary cancer cells. Moreover, its pro-apoptotic effects were enhanced by Wnt-pathway inhibitors. The activity of Akt inhibitor was even higher (by twofold) in 3D spheroids in comparison to cells grown in monolayer. The synergistic reduction in the growth of spheroids was observed between Akt inhibitor and IWP-O1. Reduced glucose consumption may play a part in the combinatorial effects of these chemicals.

CONCLUSION

The results point to the therapeutic potential of the combinatorial use of Wnt inhibitors together with Akt inhibitors in HNSCC.

MicroRNA-934 promotes colorectal cancer cell proliferation by directly targeting Dickkopf-related protein 2

Increasing evidence demonstrates that dysregulation of microRNAs (miRNAs/miRs) is implicated in the development of colorectal cancer. However, the biological functions of several differentially expressed miRNAs remain unknown. In the present study, a bioinformatic analysis of a previously published microarray data and reverse transcription-quantitative PCR analysis demonstrated that miR-934 expression was upregulated in colorectal cancer samples collected from patients. Mechanistically, Dickkopf-related protein 2 (DDK2) was identified as a novel target gene of miR-934 in colorectal cancer cells. Knockdown of DDK2 reversed the inactivation of Wnt signaling pathway induced using miR-934 inhibitor in colorectal cancer cells. In addition, DDK2 silencing reversed miR-934 inhibitor-induced cell proliferation inhibition and elevation of cell apoptosis. The results demonstrated that DDK2 mRNA expression was negatively associated with miR-934 expression in colorectal tumors. Collectively, the results of the present study demonstrated that the miR-934/DDK2 axis regulated colorectal cancer cell proliferation, suggesting that miR-934 may be a biomarker for patients with colorectal cancer.

Targeting of Deregulated Wnt/β-Catenin Signaling by PRI-724 and LGK974 Inhibitors in Germ Cell Tumor Cell Lines

The majority of patients with testicular germ cell tumors (GCTs) can be cured with cisplatin-based chemotherapy. However, for a subset of patients present with cisplatin-refractory disease, which confers a poor prognosis, the treatment options are limited. Novel therapies are therefore urgently needed to improve outcomes in this challenging patient population. It has previously been shown that Wnt/β-catenin signaling is active in GCTs suggesting that its inhibitors LGK974 and PRI-724 may show promise in the management of cisplatin-refractory GCTs. We herein investigated whether LGK-974 and PRI-724 provide a treatment effect in cisplatin-resistant GCT cell lines. Taking a genoproteomic approach and utilizing xenograft models we found the increased level of β-catenin in 2 of 4 cisplatin-resistant (CisR) cell lines (TCam-2 CisR and NCCIT CisR) and the decreased level of β-catenin and cyclin D1 in cisplatin-resistant NTERA-2 CisR cell line. While the effect of treatment with LGK974 was limited or none, the NTERA-2 CisR exhibited the increased sensitivity to PRI-724 in comparison with parental cell line. Furthermore, the pro-apoptotic effect of PRI-724 was documented in all cell lines. Our data strongly suggests that a Wnt/β-catenin signaling is altered in cisplatin-resistant GCT cell lines and the inhibition with PRI-724 is effective in NTERA-2 CisR cells. Further evaluation of Wnt/β-catenin pathway inhibition in GCTs is therefore warranted.

CREB-binding protein (CBP) gene family regulates planarian survival and stem cell differentiation

In developmental biology, the regulation of stem cell plasticity and differentiation remains an open question. CBP(CREB-binding protein)/p300 is a conserved gene family that functions as a transcriptional co-activator and plays important roles in a wide range of cellular processes, including cell death, the DNA damage response, and tumorigenesis. The acetyl transferase activity of CBPs is particularly important, as histone and non-histone acetylation results in changes in chromatin architecture and protein activity that affect gene expression. Many studies have described the conserved functions of CBP/p300 in stem cell proliferation and differentiation. The planarian Schmidtea mediterranea is an excellent model for the in vivo study of the molecular mechanisms underlying stem cell differentiation during regeneration. However, how this process is regulated genetically and epigenetically is not well-understood yet. We identified 5 distinct Smed-cbp genes in S. mediterranea that show different expression patterns. Functional analyses revealed that Smed-cbp-2 appears to be essential for stem cell maintenance. On the other hand, the silencing of Smed-cbp-3 resulted in the growth of blastemas that were apparently normal, but remained largely unpigmented and undifferentiated. Smed-cbp-3 silencing also affected the differentiation of several cell lineages including neural, epidermal, digestive, and excretory cell types. Finally, we analysed the predicted interactomes of CBP-2 and CBP-3 as an initial step to better understand their functions in planarian stem cell biology. Our results indicate that planarian cbp genes play key roles in stem cell maintenance and differentiation.

Targeting the Wnt/β-catenin signaling pathway in cancer

The aberrant Wnt/β-catenin signaling pathway facilitates cancer stem cell renewal, cell proliferation and differentiation, thus exerting crucial roles in tumorigenesis and therapy response. Accumulated investigations highlight the therapeutic potential of agents targeting Wnt/β-catenin signaling in cancer. Wnt ligand/ receptor interface, β-catenin destruction complex and TCF/β-catenin transcription complex are key components of the cascade and have been targeted with interventions in preclinical and clinical evaluations. This scoping review aims at outlining the latest progress on the current approaches and perspectives of Wnt/β-catenin signaling pathway targeted therapy in various cancer types. Better understanding of the updates on the inhibitors, antagonists and activators of Wnt/β-catenin pathway rationalizes innovative strategies for personalized cancer treatment. Further investigations are warranted to confirm precise and secure targeted agents and achieve optimal use with clinical benefits in malignant diseases.

Impact of Wnt/β-Catenin Inhibition on Cell Proliferation through CDC25A Downregulation in Soft Tissue Sarcomas

Simple Summary

Growing evidence suggests that Wnt signaling may be crucial for tumorigenesis and progression of soft tissue sarcomas (STS). Inhibitors of this pathway are currently in clinical trials or pre-clinical studies in order to validate its utility in different neoplasia. One of this inhibitors, PRI-724, is showing promising results for advanced pancreatic adenocarcinoma or ovarian cancer. We found that PRI-724 is able to suppress cell viability/proliferation and to increase cell death rates of soft tissue sarcomas cells in vitro. CDC25A, a target gene of Wnt signaling pathway, is essential for STS proliferation because its downregulation via siRNA was able to mimic the effect of PRT-724 on cell cycle arrest and evaluation of NCBI/GenBank data confirmed its overexpression in STS patients’ samples. Moreover, in vitro administration of PRI-724 along with standard STS chemotherapeutic drugs improved the efficacy of chemotherapy, suggesting that Wnt inhibition could be a promising new therapeutic strategy in STS.

Abstract

The Wnt signaling pathway is an important cellular mechanism for regulating differentiation processes as well as cell cycle events, and different inhibitors of this pathway, for example, PRI-724, are showing promising results in clinical trials for treatment of advanced pancreatic adenocarcinoma or ovarian cancer. Growing evidence suggests that Wnt signaling may also be crucial for tumorigenesis and progression of soft tissue sarcomas (STS), a malignant neoplasm with few therapeutic options at an advanced state. Our study with several STS cell lines and primary cultures shows that inhibition of Wnt/β-catenin signaling with PRI-724 is able to suppress cell viability/proliferation and to increase cell death rates. TCF/β-catenin-mediated transcriptional activity is decreased in treated cells, leading to downregulation of its target genes CCND1 and CDC25A. The latter was critical because its downregulation via siRNA was able to mimic the effect of PRI-724 on cell cycle arrest and cell death induction. An evaluation of NCBI/GenBank data confirmed that CDC25A mRNA is elevated in STS patients. Importantly, PRI-724 in combination with standard STS chemotherapeutics doxorubicin or trabectedin enhanced their antitumoral effect in a synergistic manner according to isobolographic analysis, suggesting that Wnt inhibition through PRI-724 could be a beneficial combination regime in patients with advanced STS.

WNT1, a target of miR-34a, promotes cervical squamous cell carcinoma proliferation and invasion by induction of an E-P cadherin switch via the WNT/β-catenin pathway

Purpose

Persistent infection with high-risk human papillomavirus (HR-HPV) is thought to play a prominent role in the initiation and progression of almost all cases of cervical cancer. Previously, we and others found that microRNA 34a (miR-34a) may be regulated by HR-HPV E6 to contribute to the development of cervical cancer. Here, we aimed to identify the oncogenic potential and clinical significance of a known miR-34a target, WNT1, in cervical squamous cell carcinoma (SCC) development and to investigate the associated mechanisms underlying cervical SCC cell proliferation and invasion.

Methods

WNT1 and miR-34a expression levels were assessed in primary cervical lesions using immunohistochemistry and qRT-PCR, respectively. The cellular effects and the expression of its associated genes were examined in cervical SCC-derived Siha and Caski cells after siRNA-WNT1 (downregulation) or miR-34a mimic (upregulation) treatment. A cervical SCC xenograft mouse model was used to investigate the in vivo effects of miR-34a overexpression. HPV-16 E6/E7 expression was inhibited by gene promoter siRNA targeting, after which the levels of miR-34a and WNT1 were examined.

Results

WNT1 protein upregulation was found to be associated with a poor prognosis in cervical SCC patients. In vitro assays in Siha and Caski cells revealed that WNT1 downregulation decreased cell proliferation and invasion, inhibited WNT/β-catenin activation and affected the expression of E-cadherin and P-cadherin. MiR-34a upregulation resulted in decreased WNT1 expression. An inverse correlation between miR-34a and WNT1 expression was also observed in primary cervical SCC tissues. In addition, we found that MiR-34a could regulate an E-cadherin to P-cadherin switch (E-P cadherin switch) to inhibit cell proliferation and tumorigenesis in vitro and in vivo via inactivation of the WNT1/β-catenin pathway. Finally, we found that decreased HPV-16 E6/E7 expression resulted in miR-34a upregulation and WNT1 downregulation in Siha and Caski cells.

Conclusions

From our results we conclude that WNT1, as a target of miR-34a, can promote cervical SCC cell proliferation and invasion by induction of an E-P cadherin switch via the WNT1/β-catenin pathway. Our results may provide new options for the treatment of patients with cervical SCC.

Electronic supplementary material

The online version of this article (10.1007/s13402-020-00506-8) contains supplementary material, which is available to authorized users.

The Significance of the Dysregulation of Canonical Wnt Signaling in Head and Neck Squamous Cell Carcinomas

The knowledge about the molecular alterations which are found in head and neck squamous cell carcinomas (HNSCC) has much increased in recent years. However, we are still awaiting the translation of this knowledge to new diagnostic and therapeutic options. Among the many molecular changes that are detected in head and neck cancer, the abnormalities in several signaling pathways, which regulate cell proliferation, cell death and stemness, seem to be especially promising with regard to the development of targeted therapies. Canonical Wnt signaling is a pathway engaged in the formation of head and neck tissues, however it is not active in adult somatic mucosal cells. The aim of this review paper is to bring together significant data related to the current knowledge on the mechanisms and functional significance of the dysregulation of the Wnt/β-catenin pathway in head and neck tumors. Research evidence related to the role of Wnt signaling activation in the stimulation of cell proliferation, migration and inhibition of apoptosis in HNSCC is presented. Moreover, its role in promoting stemness traits in head and neck cancer stem-like cells is described. Evidence corroborating the hypothesis that the Wnt signaling pathway is a very promising target of novel therapeutic interventions in HNSCC is also discussed.

Porcupine Inhibitor LGK974 Downregulates the Wnt Signaling Pathway and Inhibits Clear Cell Renal Cell Carcinoma

Targeted therapy for kidney cancer has achieved significant clinical results. However, because most patients who use targeted therapy will develop drug resistance, we still need to constantly explore new therapeutic targets. Although porcupine (PORCN) as a palmitoyltransferase plays a crucial role in the activation and secretion of Wnt proteins and affects the activity of the Wnt signaling pathway, little is known about the role of PORCN in clear cell renal cell carcinoma (ccRCC). We found that PORCN is highly expressed in renal cancer cell lines and patients with renal cell carcinoma with high expression of PORCN have a poor prognosis. Pathway analysis of PORCN and its related proteins showed that PORCN played a role through the Wnt signaling pathway, and there was a strong coexpression relationship between PORCN and Wnt proteins. Therefore, PORCN may be a potential and effective target for ccRCC. In the present study, we found that LGK974 could inhibit proliferation and colony formation and induce apoptosis in ccRCC cells. We also found that LGK974 could inhibit the migration and invasion of renal cell carcinoma and reduce the expression of mesenchymal markers. After treatment with LGK974, the expression level of β-catenin, a key protein in the classical Wnt pathway, was significantly decreased, and the expression levels of the target genes cyclin D1, c-Myc, MMP9, and MMP2 in the Wnt signaling pathway were also significantly decreased, which represented a significant decrease in the activity of the Wnt signaling pathway. At the same time, the cycle of renal cancer cells was significantly blocked. In conclusion, our results indicate that LGK974 could significantly inhibit the progression of renal cancer cells in a safe concentration range, so PORCN may be a safe and effective target for patients with renal cancer.

Identification and potential mechanisms of a 4-lncRNA signature that predicts prognosis in patients with laryngeal cancer

Purpose

This study aimed to describe the use of a novel 4-lncRNA signature to predict prognosis in patients with laryngeal cancer and to explore its possible mechanisms.

Methods

We identified lncRNAs that were differentially expressed between 111 tumor tissue samples and 12 matched normal tissue samples from The Cancer Genome Atlas Database (TCGA). We used Cox regression analysis to identify lncRNAs that were correlated with prognosis. A 4-lncRNA signature was developed to predict the prognosis of patients with laryngeal cancer. The receiver operating characteristic (ROC) curves and area under the curve (AUC) were used to verify the validity of this Cox regression model, and an independent prognosis analysis was used to confirm that the 4-lncRNA signature was an independent prognostic factor. Furthermore, the function of these lncRNAs was inferred using related gene prediction and Gene ontology (GO) enrichment analysis in order to clarify the possible mechanisms underlying their predictive ability.

Results

In total, 214 differentially expressed lncRNAs were identified, and a 4-lncRNA signature was constructed using Cox survival analysis. The risk coefficients in the multivariate Cox analysis revealed that LINC02154 and MNX1-AS1 are risk factors for laryngeal cancer, whereas MYHAS and LINC01281 appear to be protective factors. The results of a functional annotation analysis suggested that the mechanisms by which these lncRNAs influence prognosis in laryngeal cancer may involve the extracellular exosome, the Notch signaling pathway, voltage-gated calcium channels, and the Wnt signaling pathway.

Conclusion

We identified a novel 4-lncRNA signature that can predict the prognosis of patients with laryngeal cancer and that may influence the prognosis of laryngeal cancer by regulating immunity, tumor apoptosis, metastasis, invasion, and other characteristics through the Notch signaling pathway, voltage-gated calcium channels, and the Wnt signaling pathway.

Electronic supplementary material

The online version of this article (10.1186/s40246-019-0230-6) contains supplementary material, which is available to authorized users.