Interference of Frizzled 1 (FZD1) reverses multidrug resistance in breast cancer cells through the Wnt/β-catenin pathway

Combined targeting of Hedgehog/GLI1 and Wnt/β-catenin pathways in mantle cell lymphoma

Mantle cell lymphoma (MCL) is a rare and aggressive form of non-Hodgkin lymphoma. Challenges in its treatment include relapse, drug resistance, and a short survival period. The Hedgehog/GLI1 (Hh/GLI1) and Wnt/β-catenin pathways are crucial in cancer cell proliferation, survival, and drug resistance, making them significant targets for anticancer research. This study aimed to assess the effectiveness of combining inhibitors for both pathways against MCL and investigate the underlying molecular mechanisms. The co-expression of key proteins from the Hh/GLI1 and Wnt/β-catenin pathways was observed in MCL. Targeting the Hh/GLI1 pathway with the GLI1 inhibitor GANT61 and the Wnt/β-catenin pathway with the CBP/β-catenin transcription inhibitor ICG-001, dual-target therapy was demonstrated to synergistically suppressed the activity of MCL cells. This approach promoted MCL cell apoptosis, induced G0/G1 phase blockade, decreased the percentage of S-phase cells, and enhanced the sensitivity of MCL cells to the drugs adriamycin and ibrutinib. Both GANT61 and ICG-001 downregulated GLI1 and β-catenin while upregulating GSK-3β expression. The interaction between Hh/GLI1 and Wnt/β-catenin pathways was mediated by GANT61-dependent Hh/GLI1 inhibition. Moreover, GLI1 knockdown combined with ICG-001 synergistically induced apoptosis and increased drug sensitivity of MCL cells to doxorubicin and ibrutinib. GANT61 attenuated the overexpression of β-catenin and decreased the inhibition of GSK-3β in MCL cells. Overall, the combined targeting of both the Hh/GLI1 and Wnt/β-catenin pathways was more effective in suppressing proliferation, inducing G0/G1 cycle retardation, promoting apoptosis, and increasing drug sensitivity of MCL cells than mono treatments. These findings emphasize the potential of combinatorial therapy for treating MCL patients.

Galectin-1 Promotes Gastric Carcinoma Progression and Cisplatin Resistance Through the NRP-1/c-JUN/Wee1 Pathway

PURPOSE

Gastric cancer (GC) is among the deadliest malignancies and the third leading cause of cancer-related deaths worldwide. Galectin-1 (Gal-1) is a primary protein secreted by cancer-associated fibroblasts (CAFs); however, its role and mechanisms of action of Gal-1 in GC remain unclear. In this study, we stimulated GC cells with exogenous human recombinant galectin-1 protein (rhGal-1) to investigate its effects on the proliferation, migration, and resistance to cisplatin.

MATERIALS AND METHODS

We used simulated rhGal-1 protein as a paracrine factor produced by CAFs to induce GC cells and investigated its promotional effects and mechanisms in GC progression and cisplatin resistance. Immunohistochemical (IHC) assay confirmed that Gal-1 expression was associated with clinicopathological parameters and correlated with the expression of neuropilin-1 (NRP-1), c-JUN, and Wee1.

RESULTS

Our study reveals Gal-1 expression was significantly associated with poor outcomes. Gal-1 boosts the proliferation and metastasis of GC cells by activating the NRP-1/C-JUN/Wee1 pathway. Gal-1 notably increases GC cell resistance to cisplatin The NRP-1 inhibitor, EG00229, effectively counteracts these effects.

CONCLUSIONS

These findings revealed a potential mechanism by which Gal-1 promotes GC growth and contributes to chemoresistance, offering new therapeutic targets for the treatment of GC.

Establishment and characterization of cisplatin-resistant cell lines from canine mammary gland tumors

The development of cisplatin resistance is one of the major causes of mammary cancer treatment failure, and is associated with changes in Sox4 gene expression. To investigate the characteristic changes that occur in canine mammary gland tumor (CMGT) cells following the development of acquired cisplatin resistance, along with the relationship between these changes and the Sox4 gene. We constructed cisplatin-resistant cell line, CHMpCIS, from the cell line CHMp, which was isolated from the primary lesion of a malignant CMGT. The biological characteristics of these cells were examined by Western blot analysis, Transwell assays, and mammosphere formation assays. Compared to CHMp cells, CHMpCIS cells exhibited elevated cisplatin resistance, apoptotic escape ability, enhanced epithelial-mesenchymal transition (EMT) and cancer stem cell (CSC) features, in addition to over-activation of the Wnt/β-catenin signaling pathway and increased Sox4 protein. In CMGT cases, CMGT tissues (CMGTT) expressed higher levels of Sox4 protein and mRNA compared to adjacent tissues (CAMGTT). We found that these changes were inhibited by silencing of Sox4 expression in CHMpCIS cells. Furthermore, activation of the Wnt/β-catenin signaling pathway increased Sox4 expression levels through a positive feedback loop. These results suggested that CHMpCIS cells circumvented the damage caused by cisplatin through altering the expression of the Sox4 gene and activating the Wnt/β-catenin pathway, thereby changing the cellular biological characteristics.

The mechanisms of multidrug resistance of breast cancer and research progress on related reversal agents

Chemotherapy is the mainstay in the treatment of breast cancer. However, many drugs that are commonly used in clinical practice have a high incidence of side effects and multidrug resistance (MDR), which is mainly caused by overexpression of drug transporters and related enzymes in breast cancer cells. In recent years, researchers have been working hard to find newer and safer drugs to overcome MDR in breast cancer. In this review, we provide the molecule mechanism of MDR in breast cancer, categorize potential lead compounds that inhibit single or multiple drug transporter proteins, as well as related enzymes. Additionally, we have summarized the structure-activity relationship (SAR) based on potential breast cancer MDR modulators with lower side effects. The development of novel approaches to suppress MDR is also addressed. These lead compounds hold great promise for exploring effective chemotherapy agents to overcome MDR, providing opportunities for curing breast cancer in the future.

FTO-mediated LINC01134 stabilization to promote chemoresistance through miR-140-3p/WNT5A/WNT pathway in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. Currently, the first-line chemotherapeutic agent for PDAC is gemcitabine (GEM). However, the chemotherapy resistance to GEM is often overlooked in the clinical treatment of PDAC due to the lack of effective biological markers. Therefore, it is crucial to find new prognostic markers and therapeutic targets for patients with PDAC. In this study, we identified a novel regulatory mechanism in the development of resistance to GEM in PDAC. Here, we report that LINC01134 was significantly upregulated in primary tumors from PDAC patients. In vitro and in vivo functional studies revealed that LINC01134 promotes PDAC resistance to GEM through facilitating stem cell features and modulating the cell cycle. Mechanistically, LINC01134 interactes with tumor suppressor miR-497-5p in PDAC cells. Increased LINC01134 downregulates miR-140-3p to promotes the oncogenic WNT5A expression. Moreover, m6A demethylase FTO participated in the upregulation of LINC01134 by maintaining LINC01134 mRNA stability through YTHDF2. Taken together, the present study suggested FTO-mediated LINC01134 stabilization to promote chemotherapy resistance to GEM through miR-140-3p/WNT5A/WNT pathway in PDAC. Our study identified new prognostic markers and new therapeutic targets for patients with PDAC.

Frizzled-3 suppression overcomes multidrug chemoresistance by Wnt/β-catenin signaling pathway inhibition in hepatocellular carcinoma cells

Multidrug resistance (MDR) is a major obstacle to the efficacy of hepatocellular carcinoma (HCC) chemotherapy. Previous studies have identified that low FZD3 predicted decreased survival after intraperitoneal versus intravenous-only chemotherapy in ovarian cancer. This study aimed to identify a potential target in HCC chemotherapy. The FZD3 expression variant in HCC cell lines was detected by RT-qPCR and western blotting. The FZD3 expression in the early recurrent HCC group (RE group) and the non-early recurrent HCC group (non-RE group) was measured by RT-qPCR. Then, the 50% inhibitory concentrations (IC50) in HCC cell lines were studied by MTT assay. TOP/FOP FLASH luciferase assay was performed to measure TCF-binding activities. We found that FZD3 was upregulated in three HCC cell lines, and the FZD3 expression was significantly higher in the RE group than in the non-RE group (P = 0.0344). A positive correlation between FZD3 and MDR1 was observed in HCC tissues (R2 = 0.6368, P = 0.0001). Then, we found that FZD3 knockdown significantly altered Huh-7 cell chemotherapeutic sensitivity to cisplatin [50.43 µM in the FZD3 siRNA (siFZD3) group vs 98.59 µM in the siRNA negative control (siNC) group; P = 0.007] or doxorubicin (7.43 µM in the siFZD3 group vs 14.93 µM in the siNC group; P = 0.017). TOP/FOP FLASH luciferase assay showed FZD3 could inhibit Wnt/β-catenin signaling in HCC cells. Moreover, FZD3 expression knockdown in SNU-449 and Huh-7 cells markedly reduced β-catenin and phosho-β-catenin (S37) protein expression, and Cyclin D1, c-myc and MDR1 were significantly decreased. This is the first study to describe the significantly increased FZD3 expression in patients with early recurrent HCC. FZD3 knockdown led to increased sensitivity to chemotherapy by Wnt/β-catenin signaling inhibition in HCC cell lines. Our study suggests FZD3 as a potential target for reversing chemoresistance in HCC.

MicroRNAs: The key players regulating the crosstalk between Hippo and Wnt/β-catenin pathways in breast cancer

Breast Cancer has the highest burden in females worldwide and is predicted to increase by many folds with increasing lifestyle related risk factors, genetic mutations, and an aging population. The Hippo signalling and Wnt signalling pathways were identified as important signal transducers involved in maintaining organ development, tissue homeostasis, cell proliferation and apoptosis. microRNAs are short nucleotide sequences which act as regulatory components driving signal transductions in most cancers and can serve as both diagnostic and prognostic markers. Several reports have implicated that deregulated Hippo as well as Wnt signalling mediated by miRNAs together drive tumorigenesis, metastases and chemoresistance in breast cancer. Recent evidences on a crosstalk between Hippo and Wnt components elucidated how these pathways might be synchronized to have overlapping functions to promote tumorigenesis. Since miRNAs are demonstrated to target most of the components in both the pathways, in this review, we talk about the crosstalk between Hippo and Wnt signalling pathways and the potential microRNAs that might regulate the interplay between the two pathways in breast cancer, which has not been explored earlier.

Biological functions and molecular interactions of Wnt/β-catenin in breast cancer: Revisiting signaling networks

Changes in lifestyle such as physical activity and eating habits have been one of the main reasons for development of various diseases in modern world, especially cancer. However, role of genetic factors in initiation of cancer cannot be ignored and Wnt/β-catenin signaling is such factor that can affect tumor progression. Breast tumor is the most malignant tumor in females and it causes high mortality and morbidity around the world. The survival and prognosis of patients are not still desirable, although there have been advances in introducing new kinds of therapies and diagnosis. The present review provides an update of Wnt/β-catenin function in breast cancer malignancy. The upregulation of Wnt is commonly observed during progression of breast tumor and confirms that tumor cells are dependent on this pathway Wnt/β-catenin induction prevents apoptosis that is of importance for mediating drug resistance. Furthermore, Wnt/β-catenin signaling induces DNA damage repair in ameliorating radio-resistance. Wnt/β-catenin enhances proliferation and metastasis of breast tumor. Wnt/β-catenin induces EMT and elevates MMP expression. Furthermore, Wnt/β-catenin participates in tumor microenvironment remodeling and due to its tumor-promoting factor, drugs for its suppression have been developed. Different kinds of upstream mediators Wnt/β-catenin signaling in breast cancer have been recognized that their targeting is a therapeutic approach. Finally, Wnt/β-catenin can be considered as a biomarker in clinical trials.

Targeted Therapy and Mechanisms of Drug Resistance in Breast Cancer

Breast cancer is the most common cause of cancer-related death in women worldwide. Multidrug resistance (MDR) has been a large hurdle in reducing BC death rates. The drug resistance mechanisms include increased drug efflux, enhanced DNA repair, senescence escape, epigenetic alterations, tumor heterogeneity, tumor microenvironment (TME), and the epithelial-to-mesenchymal transition (EMT), which make it challenging to overcome. This review aims to explain the mechanisms of resistance in BC further, identify viable drug targets, and elucidate how those targets relate to the progression of BC and drug resistance.

FZD1/KLF10-hsa-miR-4762-5p/miR-224-3p-circular RNAs axis as prognostic biomarkers and therapeutic targets for glioblastoma: a comprehensive report

BACKGROUND

The circular RNA (circRNA) plays a vital role in the pathogenesis of tumors as a competitive endogenous RNA (ceRNA). Given the high aggressiveness and fatality rate of glioblastoma (GBM) as well as poor prognosis, it is necessary to construct a circRNA-related ceRNA network for further studies on the mechanism of GBM and identify possible biomarkers as well as therapeutic drugs.

METHODS

Three datasets from the gene expression omnibus (GEO) database were downloaded to distinguish differential circRNAs, microRNAs, and messenger RNAs respectively in GBM. With the help of GEPIA2, circBank, CSCD, TargetScan, miRDB, and miRTarBase databases, we established a circRNAs-related ceRNA network in GBM. Functional enrichments were employed to profile the most relevant mRNAs to indirectly clarify the mechanisms of the ceRNA network. Based on the expression profile data and survival information of GBM patients from the GEO and the cancer genome atlas (TCGA) databases, we performed survival analysis to select prognostic mRNAs and constructed a novel circRNA-miRNA-mRNA central regulatory subnetwork. The DGIdb database was used to find potential drug-gene interactions.

RESULTS

The datasets obtained from the GEO and TCGA databases were analyzed, and 504 differentially expressed mRNAs (DEmRNAs), 71 differentially expressed microRNAs (DEmiRNAs), and 270 differentially expressed circRNAs (DEcircRNAs) were screened out. The novel ceRNA regulatory network included 22 circRNAs, 11 miRNAs, and 15 mRNAs. FZD1 and KLF10 were significantly correlated with the overall survival rate of patients with GBM (P < 0.05). The final survival subnetwork contained six circRNAs, two miRNAs, and two mRNAs. Two small-molecule compounds and one antibody could be used as therapeutic drugs for GBM. Interestingly, the Wnt signaling pathway appeared in both KEGG and GO functional terms.

CONCLUSIONS

Results of this study demonstrate that FZD1 and KLF10 may exert regulatory functions in GBM, and the ceRNA-mediated network could be a therapeutic strategy for GBM.

Inhibition of WNT signaling by conjugated microRNA nano-carriers: A new therapeutic approach for treating triple-negative breast cancer a perspective review

Triple-Negative Breast Cancer is the most aggressive form and accounts the 15%-25% of all breast cancer. Receptors are absent in triple-negative breast cancer, which makes them unresponsive to the current hormonal therapies. The patients with TNBC are left with the option of cytotoxic chemotherapy. The Wnt pathways are connected to cancer, and when activated, they result in mammary hyperplasia and tumors. The tumor suppressor microRNAs can block tumor cell proliferation, invasion, and migration, lead to cancer cell death, and are also known to down-regulate the WNT signaling. Nanoparticles with microRNA have been seen to be more effective when compared with their single release. In this review, we have tried to understand how Wnt signaling plays a crucial role in TNBC, EMT, metastasis, anti-drug resistance, and regulation of Wnt by microRNA. The role of nano-carriers in delivering micro-RNA. The clinical biomarkers, including the present state-of-the-art, involve novel pathways of Wnt.

Notch signaling pathway: a comprehensive prognostic and gene expression profile analysis in breast cancer

Breast cancer is a complex disease exhibiting a great degree of heterogeneity due to different molecular subtypes. Notch signaling regulates the differentiation of breast epithelial cells during normal development and plays a crucial role in breast cancer progression through the abnormal expression of the Notch up-and down-stream effectors. To date, there are only a few patient-centered clinical studies using datasets characterizing the role of Notch signaling pathway regulators in breast cancer; thus, we investigate the role and functionality of these factors in different subtypes using publicly available databases containing records from large studies. High-throughput genomic data and clinical information extracted from TCGA were analyzed. We performed Kaplan-Meier survival and differential gene expression analyses using the HALLMARK_NOTCH_SIGNALING gene set. To determine if epigenetic regulation of the Notch regulators contributes to their expression, we analyzed methylation levels of these factors using the TCGA HumanMethylation450 Array data. Notch receptors and ligands expression is generally associated with the tumor subtype, grade, and stage. Furthermore, we showed gene expression levels of most Notch factors were associated with DNA methylation rate. Modulating the expression levels of Notch receptors and effectors can be a potential therapeutic approach for breast cancer. As we outline herein, elucidating the novel prognostic and regulatory roles of Notch implicate this pathway as an essential mediator controlling breast cancer progression.

Wnt Signaling in the Breast: From Development to Disease

The Wnt cascade is a primordial developmental signaling pathway that plays a myriad of essential functions throughout development and adult homeostasis in virtually all animal species. Aberrant Wnt activity is implicated in embryonic and tissue morphogenesis defects, and several diseases, most notably cancer. The role of Wnt signaling in mammary gland development and breast cancer initiation, maintenance, and progression is far from being completely understood and is rather shrouded in controversy. In this review, we dissect the fundamental role of Wnt signaling in mammary gland development and adult homeostasis and explore how defects in its tightly regulated and intricated molecular network are interlinked with cancer, with a focus on the breast.

Fos-Related Antigen 1 May Cause Wnt-Fzd Signaling Pathway-Related Nephroblastoma in Children

This study aimed to investigate the role of the primary Fos-related antigen 1 (Fosl-1) oncogene in nephroblastoma by studying 60 childhood nephroblastoma and 58 paraneoplastic carcinoma cases. The Fosl-1 expression was detected using immunohistochemistry. In vitro culture of nephroblastoma cells was performed by viral transfection to establish Fosl-1 overexpression and gene knockout models. Flow cytometry and nano-PCR were used to detect apoptosis and mRNA expression in related pathway genes. Immunohistochemical results showed that the positive expression of Fosl-1 in the nuclei of nephroblastoma tissue was 78%, among which metastasis rate was 61.7%; correspondingly, it was 8%, and 100% in adjacent tissues. The qPCR results indicated that MMP9, Wnt1, and Fzd1 were significantly upregulated after Fosl-1 overexpression compared with the normal embryonic tissue cells, control, and gene knockout groups (P <0.05). Fosl-1 could cause the occurrence, development, and metastasis of childhood nephroblastoma through wingless/int1/Frizzled-related signaling pathways.

Computational Analysis of Drug Resistance Network in Lung Adenocarcinoma

BACKGROUND

Lung cancer is a significant health problem and accounts for one-third of the deaths worldwide. A great majority of these deaths are caused by Non-Small Cell Lung Cancer (NSCLC). Chemotherapy is the leading treatment method for NSCLC, but resistance to chemotherapeutics is an important limiting factor that reduces the treatment success of patients with NSCLC.

OBJECTIVE

In this study, the relationship between differentially expressed genes affecting the survival of the patients, according to the bioinformatics analyses, and the mechanism of drug resistance is investigated for nonsmall cell lung adenocarcinoma patients.

METHODS

Five hundred thirteen patient samples were compared with fifty-nine control samples. The employed dataset was downloaded from The Cancer Genome Atlas (TCGA) database. The information on how the drug activity altered against the expressional diversification of the genes was extracted from the NCI-60 database. Four hundred thirty-three drugs with known Mechanism of Action (MoA) were analyzed. Diversifications of the activity of these drugs related to genes were considered based on nine lung cancer cell lines virtually. The analyses were performed using R programming language, GDCRNATools, rcellminer, and Cytoscape.

RESULTS

This work analyzed the common signaling pathways and expressional alterations of the proteins in these pathways associated with survival and drug resistance in lung adenocarcinoma. Deduced computational data demonstrated that proteins of EGFR, JNK/MAPK, NF-κB, PI3K /AKT/mTOR, JAK/STAT, and Wnt signaling pathways were associated with the molecular mechanism of resistance to anticancer drugs in NSCLC cells.

CONCLUSION

To understand the relationships between resistance to anticancer drugs and EGFR, JNK/MAPK, NF-κB, PI3K /AKT/mTOR, JAK/STAT, and Wnt signaling pathways is an important approach to design effective therapeutics for individuals with NSCLC adenocarcinoma.

Tumour Microenvironment Stress Promotes the Development of Drug Resistance

Multi-drug resistance (MDR) is a leading cause of cancer-related death, and it continues to be a major barrier to cancer treatment. The tumour microenvironment (TME) has proven to play an essential role in not only cancer progression and metastasis, but also the development of resistance to chemotherapy. Despite the significant advances in the efficacy of anti-cancer therapies, the development of drug resistance remains a major impediment to therapeutic success. This review highlights the interplay between various factors within the TME that collectively initiate or propagate MDR. The key TME-mediated mechanisms of MDR regulation that will be discussed herein include (1) altered metabolic processing and the reactive oxygen species (ROS)-hypoxia inducible factor (HIF) axis; (2) changes in stromal cells; (3) increased cancer cell survival via autophagy and failure of apoptosis; (4) altered drug delivery, uptake, or efflux and (5) the induction of a cancer stem cell (CSC) phenotype. The review also discusses thought-provoking ideas that may assist in overcoming the TME-induced MDR. We conclude that stressors from the TME and exposure to chemotherapeutic agents are strongly linked to the development of MDR in cancer cells. Therefore, there remains a vast area for potential research to further elicit the interplay between factors existing both within and outside the TME. Elucidating the mechanisms within this network is essential for developing new therapeutic strategies that are less prone to failure due to the development of resistance in cancer cells.

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.

Triple-negative breast cancer: understanding Wnt signaling in drug resistance

Triple-negative breast cancer (TNBC) is not as prevalent as hormone receptor or HER2-positive breast cancers and all receptor tests come back negative. More importantly, the heterogeneity and complexity of the TNBC on the molecular and clinical levels have limited the successful development of novel therapeutic strategies and led to intrinsic or developed resistance to chemotherapies and new therapeutic agents. Studies have demonstrated deregulation of Wnt/β-catenin signaling in tumorigenesis which plays decisive roles at the low survival rate of patients and facilitates resistance to currently existing therapies. This review summarizes mechanisms of Wnt/β-catenin signaling for resistance development in TNBC, the complex interaction between Wnt/β-catenin signaling, and the transactivated receptor tyrosine kinase (RTK) signaling pathways, lymphocytic infiltration, epithelial-mesenchymal transition (EMT), and induction of metastasis. Such associations and how these pathways interact in the development and progression of cancer have led to the careful analysis and development of new and effective combination therapies without generating significant toxicity and resistance.

Molecular Mechanisms Underlying the Anti-Breast Cancer Stem Cell Activity of Pterocladia capillacea and Corallina officinalis Polysaccharides

OBJECTIVE

This study aimed to appraise the activity of Pterocladia capillacea and Corallina officinalis polysaccharides against breast cancer stem cells (BCSCs). P. capillacea and C. officinalis polysaccharides were characterized to be sulfated polysaccharide-protein complexes.

METHODS

Cytotoxicity of the polysaccharides against MDA-MB-231 and MCF-7 cell lines along with their impact on CD44+/CD24- and aldehyde dehydrogenase 1(ALDH1) positive BCSC population were determined. Their effect on gene expression of CSC markers, Wnt/β-catenin and Notch signaling pathways was evaluated.

RESULTS

P. capillacea and C. officinalis polysaccharides inhibited the growth of breast cancer cells and reduced BCSC subpopulation. P. capillacea polysaccharides significantly down-regulated OCT4, SOX2, ALDH1A3 and vimentin in MDA-MB-231 as well as in MCF-7 cells except for vimentin that was up-regulated in MCF-7 cells. C. officinalis polysaccharides exhibited similar effects except for OCT4 that was up-regulated in MDA-MB-231 cells. Significant suppression of Cyclin D1 gene expression was noted in MDA-MB-231 and MCF-7 cells treated with P. capillacea or C. officinalis polysaccharides. β-catenin and c-Myc genes were significantly down-regulated in MDA-MB-231 cells treated with C. officinalis and P. capillacea polysaccharides, respectively, while being up-regulated in MCF-7 cells treated with either of them. Additionally, P. capillacea and C. officinalis polysaccharides significantly down-regulated Hes1 gene in MCF-7 cells despite increasing Notch1 gene expression level. However, significant down-regulation of Notch1 gene was observed in MDA-MB-231 cells treated with P. capillacea polysaccharides.

CONCLUSION

Collectively, this study provides evidence for the effectiveness of P. capillacea and C. officinalis polysaccharides in targeting BCSCs through interfering with substantial signaling pathways contributing to their functionality.

Messing Up the Cancer Stem Cell Chemoresistance Mechanisms Supported by Tumor Microenvironment

Despite the recent advances in cancer patient management and in the development of targeted therapies, systemic chemotherapy is currently used as a first-line treatment for many cancer types. After an initial partial response, patients become refractory to standard therapy fostering rapid tumor progression. Compelling evidence highlights that the resistance to chemotherapeutic regimens is a peculiarity of a subpopulation of cancer cells within tumor mass, known as cancer stem cells (CSCs). This cellular compartment is endowed with tumor-initiating and metastasis formation capabilities. CSC chemoresistance is sustained by a plethora of grow factors and cytokines released by neighboring tumor microenvironment (TME), which is mainly composed by adipocytes, cancer-associated fibroblasts (CAFs), immune and endothelial cells. TME strengthens CSC refractoriness to standard and targeted therapies by enhancing survival signaling pathways, DNA repair machinery, expression of drug efflux transporters and anti-apoptotic proteins. In the last years many efforts have been made to understand CSC-TME crosstalk and develop therapeutic strategy halting this interplay. Here, we report the combinatorial approaches, which perturb the interaction network between CSCs and the different component of TME.

LINC00942 Promotes Tumor Proliferation and Metastasis in Lung Adenocarcinoma via FZD1 Upregulation

BACKGROUND

Long non-coding RNAs (lncRNAs) have been reported to play important roles in the progression of human cancers. Herein, bioinformatic analysis identified that LINC00942 was a highly overexpressed lncRNA in lung adenocarcinoma (LUAD). The present study aimed to explore the roles and possible molecular mechanisms of LINC00942 in LUAD.

METHODS

First, on the basis of TCGA database, the expression and prognosis of LINC00942 were analyzed in LUAD tissues. Then, si-LINC00942 was transfected into A549 and H1299 cells to knockdown the expression of LINC00942. Cell viability was detected by MTT assay. Flow cytometry was used to analyze cell apoptosis. The expressions of PCNA, Bax, Bcl-2, and wnt/β-catenin pathway proteins were detected by western blotting. Dual-luciferase reporter assay was used to evaluate the regulatory relationship between LINC00942 and miR-5006-5p, or miR-5006-5p and FZD1.

RESULTS

We discovered that LINC00942 was up-regulated in LUAD tissues compared with adjacent tissues. Besides, we found the increased LINC00942 expression was associated with poor survival. In addition, silencing of LINC00942 suppressed the proliferation, migration, invasion and facilitated the apoptosis of A549 and H1299 cells. Moreover, silencing of LINC00942 repressed the expression of PCNA, Bcl-2, and enhanced Bax expression in A549 and H1299 cells. Mechanically, LINC00942 exerted its effects via enhancing Wnt signaling. LINC00942 functioned as competing endogenous RNA (ceRNA) by binding to miR-5006-5p, upregulating the expression of FZD1, which was a direct target of miR-5006-5p.

CONCLUSION

Our findings indicated that LINC00942/miR-5006-5p/FZD1 axis played important roles in LUAD growth through enhancing Wnt signaling. LINC00942/miR-5006-5p/FZD1 axis might serve as a potential biomarker and therapeutic target for LUAD treatment.

Aspects of the Tumor Microenvironment Involved in Immune Resistance and Drug Resistance

The tumor microenvironment (TME) is a complex and ever-changing "rogue organ" composed of its own blood supply, lymphatic and nervous systems, stroma, immune cells and extracellular matrix (ECM). These complex components, utilizing both benign and malignant cells, nurture the harsh, immunosuppressive and nutrient-deficient environment necessary for tumor cell growth, proliferation and phenotypic flexibility and variation. An important aspect of the TME is cellular crosstalk and cell-to-ECM communication. This interaction induces the release of soluble factors responsible for immune evasion and ECM remodeling, which further contribute to therapy resistance. Other aspects are the presence of exosomes contributed by both malignant and benign cells, circulating deregulated microRNAs and TME-specific metabolic patterns which further potentiate the progression and/or resistance to therapy. In addition to biochemical signaling, specific TME characteristics such as the hypoxic environment, metabolic derangements, and abnormal mechanical forces have been implicated in the development of treatment resistance. In this review, we will provide an overview of tumor microenvironmental composition, structure, and features that influence immune suppression and contribute to treatment resistance.

Heat Shock Protein 90 Triggers Multi-Drug Resistance of Ovarian Cancer via AKT/GSK3β/β-Catenin Signaling

Ovarian cancer is the most lethal gynaecologic tumor, with which multi-drug resistance as the major therapeutic hindrance. Heat shock protein 90 (Hsp90) has been involved in cancer malignant behaviors. However, its role and mechanism in multi-drug resistance of ovarian cancer remains poorly understood. Our results demonstrated that Hsp90 was overexpressed in multi-drug resistant ovarian cancer cells. Hsp90 downregulation by shHsp90 or inhibitor BIIB021 increased the sensitivity of multi-drug resistant ovarian cancer cells to paclitaxel and cisplatin, and augmented the drugs-induced apoptosis. Hsp90 positively regulated the expressions of multi-drug resistance protein 1 (P-gp/MDR1), breast cancer resistance protein (BCRP), Survivin and Bcl-2 expressions closely associated with multi-drug resistance. Moreover, overexpression of Hsp90 promoted β-catenin accumulation, while Hsp90 downregulation decreased the accumulation, nuclear translocation and transcriptional activity of β-catenin. We also identified that β-catenin was responsible for Hsp90-mediated expressions of P-gp, BCRP, Survivin, and Bcl-2. Furthermore, Hsp90 enhanced the AKT/GSK3β signaling, and AKT signaling played a critical role in Hsp90-induced accumulation and transcriptional activity of β-catenin, as well as multi-drug resistance to paclitaxel and cisplatin. In conclusion, Hsp90 enhanced the AKT/GSK3β/β-catenin signaling to induce multi-drug resistance of ovarian cancer. Suppressing Hsp90 chemosensitized multi-drug resistant ovarian cancer cells via impairing the AKT/GSK3β/β-catenin signaling, providing a promising therapeutic strategy for a successful treatment of ovarian cancer.

FOLFOX Therapy Induces Feedback Upregulation of CD44v6 through YB-1 to Maintain Stemness in Colon Initiating Cells

Cancer initiating cells (CICs) drive tumor formation and drug-resistance, but how they develop drug-resistance characteristics is not well understood. In this study, we demonstrate that chemotherapeutic agent FOLFOX, commonly used for drug-resistant/metastatic colorectal cancer (CRC) treatment, induces overexpression of CD44v6, MDR1, and oncogenic transcription/translation factor Y-box-binding protein-1 (YB-1). Our study revealed that CD44v6, a receptor for hyaluronan, increased the YB-1 expression through PGE2/EP1-mTOR pathway. Deleting CD44v6, and YB-1 by the CRISPR/Cas9 system attenuates the in vitro and in vivo tumor growth of CICs from FOLFOX resistant cells. The results of DNA:CD44v6 immunoprecipitated complexes by ChIP (chromatin-immunoprecipitation) assay showed that CD44v6 maintained the stemness traits by promoting several antiapoptotic and stemness genes, including cyclin-D1,BCL2,FZD1,GINS-1, and MMP9. Further, computer-based analysis of the clones obtained from the DNA:CD44v6 complex revealed the presence of various consensus binding sites for core stemness-associated transcription factors “CTOS” (c-Myc, TWIST1, OCT4, and SOX2). Simultaneous expressions of CD44v6 and CTOS in CD44v6 knockout CICs reverted differentiated CD44v6-knockout CICs into CICs. Finally, this study for the first time describes a positive feedback loop that couples YB-1 induction and CD44 alternative splicing to sustain the MDR1 and CD44v6 expressions, and CD44v6 is required for the reversion of differentiated tumor cells into CICs.

Wnt signaling in breast cancer: biological mechanisms, challenges and opportunities

Wnt signaling is a highly conserved signaling pathway that plays a critical role in controlling embryonic and organ development, as well as cancer progression. Genome-wide sequencing and gene expression profile analyses have demonstrated that Wnt signaling is involved mainly in the processes of breast cancer proliferation and metastasis. The most recent studies have indicated that Wnt signaling is also crucial in breast cancer immune microenvironment regulation, stemness maintenance, therapeutic resistance, phenotype shaping, etc. Wnt/β-Catenin, Wnt-planar cell polarity (PCP), and Wnt-Ca2+ signaling are three well-established Wnt signaling pathways that share overlapping components and play different roles in breast cancer progression. In this review, we summarize the main findings concerning the relationship between Wnt signaling and breast cancer and provide an overview of existing mechanisms, challenges, and potential opportunities for advancing the therapy and diagnosis of breast cancer.

lncRNA VIM‑AS1 promotes cell proliferation, metastasis and epithelial‑mesenchymal transition by activating the Wnt/β‑catenin pathway in gastric cancer

The present study aimed to explore the biological functions and molecular mechanisms of the long non-coding RNA VIM antisense RNA 1 (VIM-AS1) in gastric cancer (GC). The expression of VIM-AS1 was analyzed in tissues from patients with GC and GC cell lines by reverse transcription-quantitative (RT-q)PCR. The relationship between VIM-AS1 expression and overall survival time of patients with GC was also assessed. To determine the biological functions of VIM-AS1, Cell Counting Kit-8 assay, colony formation assay, flow cytometry, wound healing assay and Transwell assay were employed. The targeting relationship among VIM-AS1, microRNA (miR)-8052 and frizzled 1 (FZD1) was verified by the dual luciferase reporter gene assay. The underlying molecular mechanism of VIM-AS1 on GC was determined by RT-qPCR and western blotting. In addition, tumor formation was detected in nude mice. The results of the present study demonstrated that VIM-AS1 was highly expressed in GC tissues and cells. In addition, VIM-AS1 expression was demonstrated to be closely related to the prognosis of patients with GC. Notably, silencing VIM-AS1 inhibited the proliferation, migration and invasion, and enhanced apoptosis of AGS and HGC-27 cells. Silencing VIM-AS1 significantly increased the protein expression levels of cleaved caspase-3, Bax and E-cadherin, but decreased the protein expression levels of Bcl-2, N-cadherin, vimentin, matrix metalloproteinase (MMP)-2, MMP-9, β-catenin, cyclin D1, C-myc and FZD1. Additionally, silencing VIM-AS1 inhibited tumor growth in nude mice. Cumulatively, the present study demonstrated that VIM-AS1 may promote cell proliferation, migration, invasion and epithelial-mesenchymal transition by regulating FDZ1 and activating the Wnt/β-catenin pathway in GC.

Frizzled Receptors in Tumors, Focusing on Signaling, Roles, Modulation Mechanisms, and Targeted Therapies

Wnt molecules play crucial roles in development and adult homeostasis through their receptors Frizzled proteins (Fzds). Fzds mediate canonical β-catenin pathway and various noncanonical β-catenin-independent pathways. Aberrant Fzd signaling is involved in many diseases including cancer. Wnt/β-catenin is a well-established oncogenic pathway involved in almost every aspect of tumor development. However, Fzd-mediated noncanonical Wnt pathways function as both tumor promoters and tumor suppressors depending on cellular context. Fzd-targeted therapies have proven to be effective on cultured tumor cells, tumor cell xenografts, mouse tumor models, and patient-derived xenografts (PDX). Moreover, Fzd-targeted therapies synergize with chemotherapy in preclinical models. However, the occurrence of fragility fractures in patients treated with Fzd-targeted agents such as OMP-54F28 and OMP-18R5 limits the development of this combination. Along with new insights on signaling, roles, and modulation mechanisms of Fzds in human tumors, more Fzd-related therapeutic targets will be developed.

Upregulation of Parkin Accelerates Osteoblastic Differentiation of Bone Marrow-Derived Mesenchymal Stem Cells and Bone Regeneration by Enhancing Autophagy and β-Catenin Signaling

Osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs) plays a key role in bone formation. Parkin, an E3 ubiquitin ligase, related to Parkinson’s disease and aging. Previous studies have indicated that Parkinson’s disease have a higher risk of osteoporotic fracture. To investigate the effects and underlying mechanism of Parkin in the osteogenic differentiation of BMSCs, osteogenic differentiation was analyzed following upregulation or downregulation of Parkin. We found that Parkin was increased during differentiation. Parkin overexpression enhanced osteo-specific markers, and downregulation of Parkin mitigated osteo-specific markers. Moreover, upregulation of Parkin promoted β-catenin expression and autophagy and vice versa. The upregulation of β-catenin enhanced autophagy, and the activation of autophagy also increased the expression of β-catenin in Parkin-downregulated BMSCs. Parkin-overexpressed cell sheets accelerated bone healing in a tibial fracture model. Based on these results, we concluded that Parkin meditates osteoblastic differentiation of BMSCs via β-catenin and autophagy signaling.

Wnt-β-catenin Signaling Pathway, the Achilles' Heels of Cancer Multidrug Resistance

BACKGROUND

Most of the anticancer chemotherapies are hampered via the development of multidrug resistance (MDR), which is the resistance of tumor cells against cytotoxic effects of multiple chemotherapeutic agents. Overexpression and/or over-activation of ATP-dependent drug efflux transporters is a key mechanism underlying MDR development. Moreover, enhancement of drug metabolism, changes in drug targets and aberrant activation of the main signaling pathways, including Wnt, Akt and NF-κB are also responsible for MDR.

METHODS

In this study, we have reviewed the roles of Wnt signaling in MDR as well as its potential therapeutic significance. Pubmed and Scopus have been searched using Wnt, β-catenin, cancer, MDR and multidrug resistance as keywords. The last search was done in March 2019. Manuscripts investigating the roles of Wnt signaling in MDR or studying the modulation of MDR through the inhibition of Wnt signaling have been involved in the study. The main focus of the manuscript is regulation of MDR related transporters by canonical Wnt signaling pathway.

RESULT AND CONCLUSION

Wnt signaling has been involved in several pathophysiological states, including carcinogenesis and embryonic development. Wnt signaling is linked to various aspects of MDR including P-glycoprotein and multidrug resistance protein 1 regulation through its canonical pathways. Aberrant activation of Wnt/β- catenin signaling leads to the induction of cancer MDR mainly through the overexpression and/or over-activation of MDR related transporters. Accordingly, Wnt/β-catenin signaling can be a potential target for modulating cancer MDR.

TRPS1 Confers Multidrug Resistance of Breast Cancer Cells by Regulating BCRP Expression

Multidrug resistance (MDR) is the major obstruction in the successful treatment of breast cancer (BCa). The elucidation of molecular events that confer chemoresistance of BCa is of major therapeutic importance. Several studies have elucidated the correlation of TRPS1 and BCa. Here we focused on the role of TRPS1 in acquisition of chemoresistance, and reported a unique role of TRPS1 renders BCa cells resistant to chemotherapeutic drugs via the regulation of BCRP expression. Bioinformation analysis based on publicly available BCa data suggested that TRPS1 overexpression linked to chemoresistance. Mechanistically, TRPS1 regulated BCRP expression and efflux transportation. Overexpression of TRPS1 led to upregulation of BCRP while its inhibition resulted in repression of BCRP. The correlation of TRPS1 and BCRP was further confirmed by immunohistochemistry in 180 BCa samples. MTT assay demonstrated that manipulation of TRPS1 expression affects the chemosensitivity of BCa cells. In total, high expression of TRPS1 confers MDR of BCa which is mediated by BCRP. Our data demonstrated a new insight into mechanisms and strategies to overcome chemoresistance in BCa.

Association between the methylation status of PCDH17 and the efficacy of neoadjuvant chemotherapy in triple-negative breast cancer

The present study aimed to assess whether the methylation status of the protocadherin 17 gene (PCDH17) in triple-negative breast cancer (TNBC) tissues was associated with the efficacy of neoadjuvant chemotherapy (NAC). The present study included 280 patients diagnosed with TNBC using core needle biopsy. Tumor pathological diagnosis was determined via hematoxylin and eosin staining. Immunohistochemical staining was used to determine estrogen receptor, progesterone receptor, human epidermal growth factor receptor-2 and Ki-67 status. PCDH17 methylation status was analyzed using methylation-specific PCR. χ² tests were performed to analyze differences between PCDH17 methylation status and TNBC clinicopathological features. Univariate and multivariate logistic regressions were used to analyze whether PCDH17 methylation status predicted a curative effect of NAC. The multivariate analysis included factors with P<0.2 from the univariate analysis and those that were clinically associated with NAC. A total of 228 patients were positive for PCDH17 methylation, while the remainder 52 were negative. Additionally, 107 patients achieved pathological complete response (pCR) after NAC. The pCR rate was 67.3% among the 52 patients negative for PCDH17 methylation and 31.6% among the 228 patients positive for PCDH17 methylation. Patients who were negative for PCDH17 methylation and had high Ki67 expression exhibited significantly higher pCR rates than their counterparts. The present results demonstrate that PCDH17 methylation status may predict the response to NAC in patients with TNBC. Therefore, this epigenetic characteristic may serve as an indicator of treatment efficacy.

Role of regulatory miRNAs of the Wnt/ β-catenin signaling pathway in tumorigenesis of breast cancer

Breast cancer is the most commonly diagnosed malignancy in women worldwide. Recently, uncontrolled expression of microRNAs was detected in several human disorders like cardiovascular, neurological, intestinal and autoimmunity diseases. MicroRNAs (miRNAs) are now investigated as novel prognostic and diagnostic biomarkers for several solid tumors like breast, lung, and gastrointestinal cancers. Current data suggest that miRNAs are implicated in various oncogenic processes implicated in breast cancer carcinogenesis trough modulating canonical Wnt pathway. Aberrant activation of Wnt/b-catenin signaling was shown to be significantly associated with tumor progression and poor prognosis in patients with breast cancer. This review presents recent findings on the molecular mechanism of microRNAs in regulation of Wnt/β-catenin signaling involved in tumorigenesis of breast cancer.

Downregulation of CXXC Finger Protein 4 Leads to a Tamoxifen-resistant Phenotype in Breast Cancer Cells Through Activation of the Wnt/β-catenin Pathway

Tamoxifen is a successful endocrine therapy drug for estrogen receptor-positive (ER+) breast cancer. However, resistance to tamoxifen compromises the efficacy of endocrine treatment. In the present study, we identified potential tamoxifen resistance-related gene markers and investigated their mechanistic details. First, we established two ER + breast cancer cell lines resistant to tamoxifen, named MCF-7/TMR and BT474/TMR. Gene expression profiling showed that CXXC finger protein 4 (CXXC4) expression is lower in MCF-7/TMR cells than in MCF-7 cells. Furthermore, CXXC4 mRNA and protein expression are lower in the resistant cell lines than in the corresponding parental cell lines. We also investigated the correlation between CXXC4 and endocrine resistance in ER + breast cancer cells. CXXC4 knockdown accelerates cell proliferation in vitro and in vivo and renders breast cancer cells insensitive to tamoxifen, whereas CXXC4 overexpression inhibits cancer cell growth and increases tamoxifen sensitivity of resistant cells. In addition, we demonstrated that CXXC4 inhibits Wnt/β-catenin signaling in cancer cells by modulating the phosphorylation of GSK-3β, influencing the integrity of the β-catenin degradation complex. Silencing the CXXC4 gene upregulates expression of cyclinD1 and c-myc (the downstream targets of Wnt signaling) and promotes cell cycle progression. Conversely, ectopic expression of CXXC4 downregulates the expression of these proteins and arrests the cell cycle in the G0/G1 phase. Finally, the small-molecule inhibitor XAV939 suppresses Wnt signaling and sensitizes resistant cells to tamoxifen. These results indicate that components of Wnt pathway that are early in response to tamoxifen could be involved as an intrinsic factor of the transition to endocrine resistance, and inhibition of Wnt signaling may be an effective therapeutic strategy to overcome tamoxifen resistance.

WNT Signaling in Tumors: The Way to Evade Drugs and Immunity

WNT/β-catenin signaling is involved in many physiological processes. Its implication in embryonic development, cell migration, and polarization has been shown. Nevertheless, alterations in this signaling have also been related with pathological events such as sustaining and proliferating the cancer stem cell (CSC) subset present in the tumor bulk. Related with this, WNT signaling has been associated with the maintenance, expansion, and epithelial-mesenchymal transition of stem cells, and furthermore with two distinctive features of this tumor population: therapeutic resistance (MDR, multidrug resistance) and immune escape. These mechanisms are developed and maintained by WNT activation through the transcriptional control of the genes involved in such processes. This review focuses on the description of the best known WNT pathways and the molecules involved in them. Special attention is given to the WNT cascade proteins deregulated in tumors, which have a decisive role in tumor survival. Some of these proteins function as extrusion pumps that, in the course of chemotherapy, expel the drugs from the cells; others help the tumoral cells hide from the immune effector mechanisms. Among the WNT targets involved in drug resistance, the drug extrusion pump MDR-1 (P-GP, ABCB1) and the cell adhesion molecules from the CD44 family are highlighted. The chemokine CCL4 and the immune checkpoint proteins CD47 and PD-L1 are included in the list of WNT target molecules with a role in immunity escape. This pathway should be a main target in cancer therapy as WNT signaling activation is essential for tumor progression and survival, even in the presence of the anti-tumoral immune response and/or antineoplastic drugs. The appropriate design and combination of anti-tumoral strategies, based on the modulation of WNT mediators and/or protein targets, could negatively affect the growth of tumoral cells, improving the efficacy of these types of therapies.

Regulation of ATP-binding cassette subfamily B member 1 by Snail contributes to chemoresistance in colorectal cancer

Although accumulating evidence has indicated the intimate association between epithelial‐mesenchymal transition (EMT) and acquired resistance to chemotherapy for colorectal cancer (CRC), the underlying mechanisms remain elusive. Herein, we reported that Snail, a crucial EMT controller, was upregulated in CRC tissues. Colorectal cancer cells overexpressing Snail were found to be more resistant to 5‐fluorouracil (5‐Fu). Mechanistic studies reveal that Snail could increase the expression of ATP‐binding cassette subfamily B member 1 (ABCB1) rather than the other 23 chemoresistance‐related genes. Additionally, knockdown of ABCB1 significantly attenuated Snail‐induced 5‐Fu resistance in CRC cells. Oxaliplatin increased Snail and ABCB1 expression in CRC cells. Snail and ABCB1 were upregulated in 5‐Fu‐resistant HCT‐8 (HCT‐8/5‐Fu) cells and inhibition of Snail decreased ABCB1 in HCT‐8/5‐Fu cells. These results confirm the vital role played by ABCB1 in Snail‐induced chemoresistance. Further investigation into the relevant molecular mechanism revealed Snail‐mediated ABCB1 upregulation was independent of β‐catenin, STAT3, PXR, CAR and Foxo3a, which are commonly involved in modulating ABCB1 transcription. Instead, Snail upregulated ABCB1 transcription by directly binding to its promoter. Clinical analysis confirms that increased Snail expression correlated significantly with tumor size (P = .018), lymph node metastasis (P = .033), distant metastasis (P = .025), clinical stage grade (P = .024), and poor prognosis (P = .045) of CRC patients. Moreover, coexpression of Snail and ABCB1 was observed in CRC patients. Our study revealed that direct regulation of ABCB1 by Snail was critical for conferring chemoresistance in CRC cells. These findings unraveled the mechanisms underlying the association between EMT and chemoresistance, and provided potential targets for CRC clinical treatment.

Requirement of the transcription factor YB-1 for maintaining the stemness of cancer stem cells and reverting differentiated cancer cells into cancer stem cells

BACKGROUND

Cancer stem cells always express high levels of stemness-associated transcription factors to maintain their features. However, the regulatory mechanism of the stemness of cancer stem cells mediated by transcription factors has not been extensively explored.

METHODS

The YB-1 gene in cancer stem cells was knocked out by the CRISPR/Cas9 system. The YB-1 knockout cancer stem cells were transfected with a vector expressing YB-1 to rescue YB-1, and then the cell proliferation, cell cycle, apoptosis, and stemness, as well as tumorigenesis in nude mice, were assessed to examine the effect of YB-1 in cancer stem cells. The target genes of YB-1 were confirmed by CHIP-seq. The totipotency or pluripotency of differentiated cancer stem cells were detected by tumorsphere formation assay and quantitative real-time PCR.

RESULTS

The deletion of YB-1 gene inhibited the proliferation of breast cancer stem cells and melanoma stem cells, leading to cell cycle arrest and apoptosis, and induced irreversible differentiation of cancer stem cells. The tumorigenicity ability of YB-1-deleted cancer stem cells was significantly reduced in vitro and in vivo. The results of ChIP-seq showed that YB-1 maintained the stemness of cancer stem cells by promoting the expressions of stemness-associated genes (FZD-1, p21, GLP-1, GINS1, and Notch2). Furthermore, simultaneous expressions of YB-1 and the other four (SOX2, POU3F2, OCT-4, and OLIG1) or five (SOX2, SALL2, OCT-4, POU3F2, and Bmi-1) transcription factors in YB-1 knockout cancer stem cells restored the stemness of YB-1 knockout cancer stem cells.

CONCLUSIONS

Our study indicated that YB-1 was required for maintaining the stemness of cancer stem cells and reverting the differentiated tumor cells into cancer stem cells.

Overexpression of FZD1 is Associated with a Good Prognosis and Resistance of Sunitinib in Clear Cell Renal Cell Carcinoma

Frizzled class receptor 1 (FZD1), a receptor for Wnt signaling pathway. Overexpression of FZD1 has been detected in many cancer tissues and cells resulting in tumor development and drug resistance. However, its expression status and prognostic merit in renal cancer still remains unclear. We screened the FZD1 mRNA in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) from TCGA database and Oncomine database. We then detected FZD1 mRNA expression in sunitinib-resistant cells and the corresponding parental cells by qRT-PCR. FZD1 level was significantly upregulated in renal cancer tissues, renal cancer cell lines and their corresponding sunitinib-resistant cells. FZD1 level was also associated with the clinicopathological characteristics of ccRCC patients that could discriminate metastasis, pathological stage, recurrence and prognosis in ccRCC patients. The Kaplan-Meier survival curve and the log-rank test revealed FZD1 was higher in lower clinical stage and grade that correlated with better overall survival (OS) and disease-free survival (DFS) in total and subgroups of ccRCC patients. Both univariate and multivariate cox regression analysis indicated that high FZD1 level was an independent predictor of good prognosis for OS (HR 0.569, P=0.001) and DFS (HR 0.559, P=0.036) in ccRCC patients. Using cBioportal program, less than 1% mutation in the patients with renal cancer was observed, the alterations in FZD1 were correlated with better OS (P=0.0404) in ccRCC patients. Finally, the result of KEGG pathway analysis predicted seven potential pathways that FZD1 and its related genes got involved in ccRCC, including Hippo signaling pathway. This indicated potential therapeutic targets of ccRCC. In conclusion, our results suggested that expression status of FZD1 had a diagnostic value and prognostic value in ccRCC patients, it also may serve as a potential drug target to relieve sunitinib resistance in renal cancer patients.

Causal Inference Network of Genes Related with Bone Metastasis of Breast Cancer and Osteoblasts Using Causal Bayesian Networks

Background

The causal networks among genes that are commonly expressed in osteoblasts and during bone metastasis (BM) of breast cancer (BC) are not well understood. Here, we developed a machine learning method to obtain a plausible causal network of genes that are commonly expressed during BM and in osteoblasts in BC.

Methods

We selected BC genes that are commonly expressed during BM and in osteoblasts from the Gene Expression Omnibus database. Bayesian Network Inference with Java Objects (Banjo) was used to obtain the Bayesian network. Genes registered as BC related genes were included as candidate genes in the implementation of Banjo. Next, we obtained the Bayesian structure and assessed the prediction rate for BM, conditional independence among nodes, and causality among nodes. Furthermore, we reported the maximum relative risks (RRs) of combined gene expression of the genes in the model.

Results

We mechanistically identified 33 significantly related and plausibly involved genes in the development of BC BM. Further model evaluations showed that 16 genes were enough for a model to be statistically significant in terms of maximum likelihood of the causal Bayesian networks (CBNs) and for correct prediction of BM of BC. Maximum RRs of combined gene expression patterns showed that the expression levels of UBIAD1, HEBP1, BTNL8, TSPO, PSAT1, and ZFP36L2 significantly affected development of BM from BC.

Conclusions

The CBN structure can be used as a reasonable inference network for accurately predicting BM in BC.

Flavonoids modulate multidrug resistance through wnt signaling in P-glycoprotein overexpressing cell lines

BACKGROUND

Wnt signaling has been linked with P-glycoprotein (P-gp) overexpression and which was mainly mediated by β-catenin nuclear translocation. Flavonoids have already been reported as modulators of the Wnt/β-catenin pathway and hence they may serve as promising agents in the reversal of P-gp mediated cancer multi drug resistance (MDR).

METHODS

In this study, we screened selected flavonoids against Wnt/β-catenin signaling molecules. The binding interaction of flavonoids (theaflavin, quercetin, rutin, epicatechin 3 gallate and tamarixetin) with GSK 3β was determined by molecular docking. Flavonoids on P-gp expression and the components of Wnt signaling in drug-resistant KBCH^R8-5 cells were analyzed by western blotting and qRT-PCR. The MDR reversal potential of these selected flavonoids against P-gp mediated drug resistance was analyzed by cytotoxicity assay in KBCH^R8-5 and MCF7/ADR cell lines. The chemosensitizing potential of flavonoids was further analyzed by observing cell cycle arrest in KBCH^R8-5 cells.

RESULTS

In this study, we observed that the components of Wnt/β-catenin pathway such as Wnt and GSK 3β were activated in multidrug resistant KBCH^R8-5 cell lines. All the flavonoids selected in this study significantly decreased the expression of Wnt and GSK 3β in KBCH^R8-5 cells and subsequently modulates P-gp overexpression in this drug-resistant cell line. Further, we observed that these flavonoids considerably decreased the doxorubicin resistance in KBCH^R8-5 and MCF7/ADR cell lines. The MDR reversal potential of flavonoids were found to be in the order of theaflavin > quercetin > rutin > epicatechin 3 gallate > tamarixetin. Moreover, we observed that flavonoids pretreatment significantly induced the doxorubicin-mediated arrest at the phase of G2/M. Further, the combinations of doxorubicin with flavonoids significantly modulate the expression of drug response genes in KBCH^R8-5 cells.

CONCLUSION

The present findings illustrate that the studied flavonoids significantly enhances doxorubicin-mediated cell death through modulating P-gp expression pattern by targeting Wnt/β-catenin signaling in drug-resistant KBCH^R8-5 cells.

Cross-Talk between Wnt and Hh Signaling Pathways in the Pathology of Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the most frequently occurring form of all cancers. The cost of care for BCC is one of the highest for all cancers in the Medicare population in the United States. Activation of Hedgehog (Hh) signaling pathway appears to be a key driver of BCC development. Studies involving mouse models have provided evidence that activation of the glioma-associated oncogene (GLI) family of transcription factors is a key step in the initiation of the tumorigenic program leading to BCC. Activation of the Wnt pathway is also observed in BCCs. In addition, the Wnt signaling pathway has been shown to be required in Hh pathway-driven development of BCC in a mouse model. Cross-talks between Wnt and Hh pathways have been observed at different levels, yet the mechanisms of these cross-talks are not fully understood. In this review, we examine the mechanism of cross-talk between Wnt and Hh signaling in BCC development and its potential relevance for treatment. Recent studies have identified insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), a direct target of the Wnt/&beta;-catenin signaling, as the factor that binds to GLI1 mRNA and upregulates its levels and activities. This mode of regulation of GLI1 appears important in BCC tumorigenesis and could be explored in the treatment of BCCs.

Heterogeneous nuclear ribonucleoprotein M promotes the progression of breast cancer by regulating the axin/β-catenin signaling pathway

Despite significant progress in the treatment of breast cancer due to advances in surgery, cytotoxic agents, and endocrine therapy, the prognosis for patients has not improved much. Accumulated evidence indicates that heterogeneous nuclear ribonucleoprotein M (hnRNPM) and Wnt/β-catenin function as tumor oncogenes in the progression of many cancers. The present study aimed to explore whether HnRNPM/β-catenin signaling molecules might serve as a genetic target for breast cancer treatment. To shed light on this issue, quantitative real-time polymerase chain reaction (qRT-PCR) detection, Western blotting, and immunohistochemical staining were performed. The hnRNPM is expressed at a much higher level in breast cancer tissues and cell lines than in noncancerous tissues and cell lines. In vitro studies revealed that overexpressed hnRNPM promoted cell proliferation and colony formation but inhibited cell apoptosis. In vivo results demonstrated that upregulation of hnRNPM dramatically increased breast cancer xenograft tumor growth. Western blotting and immunofluorescence studies revealed that hnRNPM markedly activated the Wnt/β-catenin pathway and catalyzed its translocation from the cytoplasm to the nucleus by targeting axin, a negative regulator of Wnt/β-catenin signaling in MCF-7 and KPL-4 cells. Elevated levels of c-Myc and cyclin D1 were observed when MCF-7 and KPL-4 cells were transfected with a hnRNPM vector. These findings indicate that the hnRNPM/axin/β-catenin signaling pathway acts as an oncogenic promoter in the progression of breast cancer, suggesting that hnRNPM may be a potential target for the treatment of this disease.

Frizzled Receptors as Potential Therapeutic Targets in Human Cancers

Frizzled receptors (FZDs) are a family of seven-span transmembrane receptors with hallmarks of G protein-coupled receptors (GPCRs) that serve as receptors for secreted Wingless-type (WNT) ligands in the WNT signaling pathway. Functionally, FZDs play crucial roles in regulating cell polarity, embryonic development, cell proliferation, formation of neural synapses, and many other processes in developing and adult organisms. In this review, we will introduce the basic structural features and review the biological function and mechanism of FZDs in the progression of human cancers, followed by an analysis of clinical relevance and therapeutic potential of FZDs. We will focus on the development of antibody-based and small molecule inhibitor-based therapeutic strategies by targeting FZDs for human cancers.

Sodium butyrate increases P-gp expression in lung cancer by upregulation of STAT3 and mRNA stabilization of ABCB1

As a new type of anticancer drug, the effect of histone deacetylase inhibitors (HDACIs) in cancer clinical therapy is disappointing owing to drug resistance. P-glycoprotein (P-gp) is clearly recognized as a multidrug resistance protein. However, the relationship between P-gp and sodium butyrate (SB), a kind of HDACIs, has not been investigated. In this study, we found that SB increased mRNA and protein expression of P-gp in lung cancer cells and the underlying mechanisms were elucidated. We found that SB treatment enhanced the mRNA and protein expression of STAT3 rather than that of β-catenin, Foxo3a, PXR, or CAR, which were reported to directly regulate the transcription of ABCB1, a P-gp-encoding gene. Interestingly, inhibition of STAT3 expression obviously attenuated SB-increased P-gp expression in lung cancer cells, indicating that STAT3 played an important role in SB-mediated P-gp upregulation. Furthermore, we found that SB increased the mRNA stability of ABCB1. In summary, this study showed that SB increased P-gp expression by facilitating transcriptional activation and improving ABCB1 mRNA stability. This study indicated that we should pay more attention to HDACIs during cancer clinical therapy.

Determination of the relationship between doxorubicin resistance and Wnt signaling pathway in HeLa and K562 cell lines

Activation of the Wnt signaling in some types of cancer and its relation with chemotherapy resistance is a very interesting issue that has been emphasized in recent years. Although, it is known that increase in the activity of β-catenin is important in blast transformation and drug resistance, the underlying mechanisms are still unclear. In this study, changes in the expression levels of 186 genes that are thought to be important in drug resistance and Wnt signaling pathways were determined by using qPCR method in doxorubicin-sensitive and -resistant HeLa and K562 cell lines. It has been observed that the genes involved in the Wnt signaling pathways are involved in more changes in HeLa/Dox cells (36 genes) than in the K562/Dox cells (17 genes). Genes important for the development of cancer resistance have been found to be significantly different in expression levels of 18 genes in HeLa/Dox cells and 20 genes in K562/Dox cells. In both cell lines, the expression of ABCB1 gene was significantly increased to 160 and 103 fold, respectively. However, despite the resistance to same drug in HeLa and K562 cell lines, it appears that the expression levels of different oncogenes and genes involved in Wnt signaling pathways have been altered. It has been found that although resistance develops to the same drug in both cell lines, the expression levels of different genes have changed. If functional analysis of these genes is performed on patient population groups, these molecules may become candidates for novel therapeutic target molecules.

A Universal Approach to Render Nanomedicine with Biological Identity Derived from Cell Membranes

Biomimetic nanoengineering built through integrating the specific cell membrane with artificially synthetic nanomedicines represents one of the most promising directions for the actualization of personalized therapy. For addressing the technical hurdle against the development of this biomimetic technology, the present report describes the in-depth exploration and optimization over each critical preparation step, including establishment of a nanoparticle-stabilized dispersion system, cargo loading, membrane coating, and product isolation. Magnetic iron oxide nanoparticles loaded with DOX is used as a typical model for the coating with cancer cell membranes, providing compact DNP@CCCM nanostructure well-characterized by various techniques. Furthermore, the feasibility of this optimized approach in constructing biomimetic membrane-coated nanomedicines has been validated on the basis of the remarkably improved biofunctions, such as the targetability, magnetic property, hemolysis risk, macrophage evasion, in vitro cytotoxicity, in vivo circulation duration, and in vivo principal component analysis postinjection. We hope this study regarding technique optimization will prompt the advancement of biomembrane-camouflaged nanoparticles as a newly emerging biomimetic technology.

Histone deacetylase inhibitors regulate P-gp expression in colorectal cancer via transcriptional activation and mRNA stabilization

Histone deacetylase inhibitors (HDACIs) are emerging as a novel class of anti-tumor drugs. But the effect of HDACIs in tumors treatment has been disappointing, which mainly due to the acquisition of resistance to HDACIs. However, the underlying mechanisms have not been clearly understood. In this study, it was found that HDACIs SAHA and TSA increased P-gp expression in CRC cells, which has been well known to contribute to drug resistant. The mechanisms underlying these effects were investigated. We showed that HDACIs enhanced transcriptional activity of P-gp protein encoding gene ABCB1. HDACIs treatment also increased the protein and mRNA expression of STAT3, but not PXR, CAR, Foxo3a or β-catenin, which are known to be involved in ABCB transcription regulation. Interestingly, knockdown of STAT3 significantly attenuated HDACIs-induced P-gp up-regulation in colorectal cancer cells, suggesting that STAT3 plays a crucial role in HDACIs-up-regulated P-gp. Furthermore, this study revealed for the first time that HDACIs enhanced the stability of ABCB1 at post-transcriptional level. Taken together, these results proved that HDACIs induced P-gp expression by two distinct ways, transcriptional activation and mRNA stabilization. Our results suggested that more attention should be paid to the cancer treatment using HDACIs since they will induce multidrug resistance in cancer cells.