Inhibition of cytoplasmic GSK-3β increases cisplatin resistance through activation of Wnt/β-catenin signaling in A549/DDP cells

Wnt signaling and tumors (Review)

Wnt signaling is a highly conserved evolutionary pathway that plays a key role in regulation of embryonic development, as well as tissue homeostasis and regeneration. Abnormalities in Wnt signaling are associated with tumorigenesis and development, leading to poor prognosis in patients with cancer. However, the pharmacological effects and mechanisms underlying Wnt signaling and its inhibition in cancer treatment remain unclear. In addition, potential side effects of inhibiting this process are not well understood. Therefore, the present review outlines the role of Wnt signaling in tumorigenesis, development, metastasis, cancer stem cells, radiotherapy resistance and tumor immunity. The present review further identifies inhibitors that target Wnt signaling to provide a potential novel direction for cancer treatment. This may facilitate early application of safe and effective drugs targeting Wnt signaling in clinical settings. An in-depth understanding of the mechanisms underlying inhibition of Wnt signaling may improve the prognosis of patients with cancer.

Amelioration of cisplatin-induced neurodegenerative changes in rats and restoration of mitochondrial biogenesis by 6-bromoindirubin-3'-oxime: The implication of the GSK-3β/PGC1-α axis

BACKGROUND

The cognitive deficits observed after treatment with chemotherapeutic drugs are obvious clinical problems. For treating chemotherapy-induced cognitive deficits (CICD), the treatment modalities must target its underlying mechanisms. Specifically, cisplatin may activate glycogen synthase kinase-3β (GSK-3β), thereby enhancing neuronal apoptosis. 6-bromoindirubin-3'-oxime (6BIO) was not investigated previously in a model of CICD. Therefore, this investigation aimed to address the impacts of GSK3 inhibition on regulating cell signaling, which contributes to neurodegeneration and cognitive impairment.

METHODS

Thirty adult male Wistar rats were randomly allocated into control groups, while two experimental groups were exposed to repeated cisplatin injections (2 mg/kg intraperitoneally (ip), twice weekly, nine injections), termed chemobrain groups. The rats in the two experimental groups were equally divided into the chemobrain group (untreated) and the chemobrain-6BIO group (treated with 6BIO at a dose of 8.5 μg/kg ip every two days, started after the last dose of cisplatin and continued for two weeks).

RESULTS

Repeated exposure to cisplatin led to a marked decline in cognitive functions. GSK3 inhibition exerted neuroprotection by decreasing the expression of p-tau and amyloid β, thereby improving cognition. 6BIO, the GSK-3β inhibitor, restored mitochondrial biogenesis by augmenting the protein levels of PGC1-α and increasing the number of mitochondria in the cerebral cortex and hippocampus.

CONCLUSION

6BIO provided neuroprotection and exhibited anti-apoptotic and anti-oxidative effects in a rat model of chemobrain.

p32/OPA1 axis-mediated mitochondrial dynamics contributes to cisplatin resistance in non-small cell lung cancer

Cisplatin resistance is a major obstacle in the treatment of non-small cell lung cancer (NSCLC). p32 and OPA1 are the key regulators of mitochondrial morphology and function. This study aims to investigate the role of the p32/OPA1 axis in cisplatin resistance in NSCLC and its underlying mechanism. The levels of p32 protein and mitochondrial fusion protein OPA1 are higher in cisplatin-resistant A549/DDP cells than in cisplatin-sensitive A549 cells, which facilitates mitochondrial fusion in A549/DDP cells. In addition, the expression of p32 and OPA1 protein is also upregulated in A549 cells during the development of cisplatin resistance. Moreover, p32 knockdown effectively downregulates the expression of OPA1, stimulates mitochondrial fission, decreases ATP generation and sensitizes A549/DDP cells to cisplatin-induced apoptosis. Furthermore, metformin significantly downregulates the expressions of p32 and OPA1 and induces mitochondrial fission and a decrease in ATP level in A549/DDP cells. The co-administration of metformin and cisplatin shows a significantly greater decrease in A549/DDP cell viability than cisplatin treatment alone. Moreover, D-erythro-Sphingosine, a potent p32 kinase activator, counteracts the metformin-induced downregulation of OPA1 and mitochondrial fission in A549/DDP cells. Taken together, these findings indicate that p32/OPA1 axis-mediated mitochondrial dynamics contributes to the acquired cisplatin resistance in NSCLC and that metformin resensitizes NSCLC to cisplatin, suggesting that targeting p32 and mitochondrial dynamics is an effective strategy for the prevention of cisplatin resistance.

Shielding and nurturing: Fibronectin as a modulator of cancer drug resistance

Resistance to chemotherapy and targeted therapies constitute a common hallmark of most cancers and represent a dominant factor fostering tumor relapse and metastasis. Fibronectin, an abundant extracellular matrix glycoprotein, has long been proposed to play an important role in the pathobiology of cancer. Recent research has unraveled the role of Fibronectin in the onset of chemoresistance against a variety of antineoplastic drugs including DNA-damaging agents, hormone receptor antagonists, tyrosine kinase inhibitors, microtubule destabilizing agents, etc. The current review summarizes the role played by Fibronectin in mediating drug resistance against diverse anticancer drugs. We have also discussed how the aberrant expression of Fibronectin drives the oncogenic signaling pathways ultimately leading to drug resistance through the inhibition of apoptosis, promotion of cancer cell growth and proliferation.

Protective effects of oridonin against osteoporosis by regulating immunity and activating the Wnt3a/β-catenin/VEGF pathway in ovariectomized mice

This study was performed with the aim of investigating the effect of oridonin (ORI) on estrogen deprivation-induced osteoporosis in mice and its mechanism. Animal experiments were used in this work to validate the anti-osteoporotic efficacy of ORI. Morphometric analysis was performed by micro-CT. A special protein meter was used to detect the content of immunoglobulin lgM, immunoglobulin lgG, complement C3 and C4 in the serum of mice. The expression of CD4⁺CD25⁺Foxp3⁺ Treg cell and CD4⁺/CD8⁺ lymphocyte subsets in mice was detected by flow cytometry. ELISA was used to detect the content of insulin-like growth factor (IGF-1), tumor necrosis factor (TNF-α), interleukin-1 (IL-1) and interleukin-6 (IL-6). In addition, key signaling molecules in the Wnt3a/β-catenin signaling pathway were detected by Western blotting. The results showed that compared with the model group, the contents of calcium and phosphorus in the femurs of mice in the ORI groups were increased, and the spleen coefficient was decreased. The ALP activity in the serum of mice in the high and medium dose ORI groups was decreased, and the uterine coefficient was increased. ORI significantly increased the maximum bending load and the maximum bending stress of the femurs of mice, increased the number of trabeculae, and repaired the bone microstructure. At the same time, ORI could significantly increase the levels of immunoglobulin (lgG and lgM) and complement (C3 and C4), increase the activity of peritoneal macrophages in mice, increase the expression of CD4⁺CD25⁺Foxp3⁺ Tregs and CD4⁺/CD8⁺ in the spleen, increase the content of IGF-1, reduce the content of TNF-α, IL-1 and IL-6 and increase the expression levels of VEGF, Wnt3a, p-GSK3β/GSK3β and β-catenin/Lamin in the femoral tissue. These results indicated that ORI might regulate the expression of VEGF through the Wnt3a/β-catenin signaling pathway, improve the immunity of mice, maintain the balance of the immune system, and promote angiogenesis, thereby improving the bone mineral density and bone tissue morphology of mice and playing an anti-osteoporotic role.

A deep tabular data learning model predicting cisplatin sensitivity identifies BCL2L1 dependency in cancer

Cisplatin, a platinum-based chemotherapeutic agent, is widely used as a front-line treatment for several malignancies. However, treatment outcomes vary widely due to intrinsic and acquired resistance. In this study, cisplatin-perturbed gene expression and pathway enrichment were used to define a gene signature, which was further utilized to develop a cisplatin sensitivity prediction model using the TabNet algorithm. The TabNet model performed better (>80 % accuracy) than all other machine learning models when compared to a wide range of machine learning algorithms. Moreover, by using feature importance and comparing predicted ovarian cancer patient samples, BCL2L1 was identified as an important gene contributing to cisplatin resistance. Furthermore, the pharmacological inhibition of BCL2L1 was found to synergistically increase cisplatin efficacy. Collectively, this study developed a tool to predict cisplatin sensitivity using cisplatin-perturbed gene expression and pathway enrichment knowledge and identified BCL2L1 as an important gene in this setting.

The emerging role of circular RNAs in drug resistance of non-small cell lung cancer

Due to the characteristics of aggressiveness and high risk of postoperative recurrence, non-small cell lung cancer (NSCLC) is a serious hazard to human health, accounting for 85% of all lung cancer cases. Drug therapies, including chemotherapy, targeted therapy and immunotherapy, are effective treatments for NSCLC in clinics. However, most patients ultimately develop drug resistance, which is also the leading cause of treatment failure in cancer. To date, the mechanisms of drug resistance have yet to be fully elucidated, thus original strategies are developed to overcome this issue. Emerging studies have illustrated that circular RNAs (circRNAs) participate in the generation of therapeutic resistance in NSCLC. CircRNAs mediate the modulations of immune cells, cytokines, autophagy, ferroptosis and metabolism in the tumor microenvironment (TME), which play essential roles in the generation of drug resistance of NSCLC. More importantly, circRNAs function as miRNAs sponges to affect specific signaling pathways, directly leading to the generation of drug resistance. Consequently, this review highlights the mechanisms underlying the relationship between circRNAs and drug resistance in NSCLC. Additionally, several therapeutic drugs associated with circRNAs are summarized, aiming to provide references for circRNAs serving as potential therapeutic targets in overcoming drug resistance in NSCLC.

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.

Drug discovery efforts toward inhibitors of canonical Wnt/β-catenin signaling pathway in the treatment of cancer: A composition-of-matter review (2010-2020)

The Wnt/β-catenin pathway has a crucial role in the proliferation and differentiation of normal cells as well as the self-renewal and pluripotency of stem cells, including cancer stem cells (CSCs). Targeting this pathway with small-molecule chemotherapeutics, discovered via conventional efforts, has proved difficult. Recently, computer-aided drug discovery efforts have produced promising chemotherapeutics. A concerted effort to develop inhibitors of this pathway through more efficient and cost-effective drug discovery methods could lead to a significant increase in clinically relevant therapeutics. Herein, patents from 2010 to 2020 are reviewed to identify those that have disclosed composition of matter for small-molecule inhibitors of the Wnt/ β-catenin pathway for cancer. We believe that such efforts will provide insights for future therapeutic candidate discovery and development in this field.

Small-Molecule Inhibitors Targeting the Canonical WNT Signaling Pathway for the Treatment of Cancer

Canonical WNT signaling is an important developmental pathway that has attracted increased attention for anticancer drug discovery. From the production and secretion of WNT ligands, their binding to membrane receptors, and the β-catenin destruction complex to the expansive β-catenin transcriptional complex, multiple components have been investigated as drug targets to modulate WNT signaling. Significant progress in developing WNT inhibitors such as porcupine inhibitors, tankyrase inhibitors, β-catenin/coactivators, protein-protein interaction inhibitors, casein kinase modulators, DVL inhibitors, and dCTPP1 inhibitors has been made, with several candidates (e.g., LGK-974, PRI-724, and ETC-159) in human clinical trials. Herein we summarize recent progress in the drug discovery and development of small-molecule inhibitors targeting the canonical WNT pathway, focusing on their specific target proteins, in vitro and in vivo activities, physicochemical properties, and therapeutic potential. The relevant opportunities and challenges toward maintaining the balance between efficacy and toxicity in effectively targeting this pathway are also highlighted.

Advanced bioinformatic analysis and pathway prediction of NSCLC cells upon cisplatin resistance

This study aims to identify pathway involvement in the development of cisplatin (cis-diamminedichloroplatinum (II); CDDP) resistance in A549 lung cancer (LC) cells by utilizing advanced bioinformatics software. We developed CDDP-resistant A549 (A549/DDP) cells through prolonged incubation with the drug and performed RNA-seq on RNA extracts to determine differential mRNA and miRNA expression between A549/DDP and A549 cells. We analyzed the gene dysregulation with Ingenuity Pathway Analysis (IPA; QIAGEN) software. In contrast to prior research, which relied on the clustering of dysregulated genes to pathways as an indication of pathway activity, we utilized the IPA software for the dynamic evaluation of pathway activity depending on the gene dysregulation levels. We predicted 15 pathways significantly contributing to the chemoresistance, with several of them to have not been previously reported or analyzed in detail. Among them, the PKR signaling, cholesterol biosynthesis, and TEC signaling pathways are included, as well as genes, such as PIK3R3, miR-34c-5p, and MDM2, among others. We also provide a preliminary analysis of SNPs and indels, present exclusively in A549/DDP cells. This study's results provide novel potential mechanisms and molecular targets that can be explored in future studies and assist in improving the understanding of the chemoresistance phenotype.

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 non-small 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 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.

Serum and Glucocorticoid-Inducible Kinase 1 (SGK1) in NSCLC Therapy

Non-small cell lung cancer (NSCLC) remains the most prevalent and one of the deadliest cancers worldwide. Despite recent success, there is still an urgent need for new therapeutic strategies. It is also becoming increasingly evident that combinatorial approaches are more effective than single modality treatments. This review proposes that the serum and glucocorticoid-inducible kinase 1 (SGK1) may represent an attractive target for therapy of NSCLC. Although ubiquitously expressed, SGK1 deletion in mice causes only mild defects of ion physiology. The frequent overexpression of SGK1 in tumors is likely stress-induced and provides a therapeutic window to spare normal tissues. SGK1 appears to promote oncogenic signaling aimed at preserving the survival and fitness of cancer cells. Most importantly, recent investigations have revealed the ability of SGK1 to skew immune-cell differentiation toward pro-tumorigenic phenotypes. Future studies are needed to fully evaluate the potential of SGK1 as a therapeutic target in combinatorial treatments of NSCLC. However, based on what is currently known, SGK1 inactivation can result in anti-oncogenic effects both on tumor cells and on the immune microenvironment. A first generation of small molecules to inactivate SGK1 has already been already produced.

Negative Effect of Reduced NME1 Expression on Recurrence-Free Survival in Early Stage Non-Small Cell Lung Cancer

This study aimed to understand whether the effect of non-metastatic cells 1 (NME1) on recurrence-free survival (RFS) in early stage non-small cell lung cancer (NSCLC) can be modified by β-catenin overexpression and cisplatin-based adjuvant chemotherapy. Expression levels of NME1 and β-catenin were analyzed using immunohistochemistry in formalin-fixed paraffin-embedded tissues from 425 early stage NSCLC patients. Reduced NME1 expression was found in 39% of samples. The median duration of follow-up was 56 months, and recurrence was found in 186 (44%) of 425 patients. The negative effect of reduced NME1 expression on RFS was worsened by cisplatin-based adjuvant chemotherapy (adjusted hazard ratio = 3.26, 95% CI = 1.16–9.17, p = 0.03). β-catenin overexpression exacerbated the effect of reduced NME1 expression on RFS and the negative effect was greater when receiving cisplatin-based adjuvant chemotherapy: among patients treated with cisplatin-based adjuvant chemotherapy, hazard ratios of patients with reduced NME1 expression increased from 5.59 (95% confidence interval (CI) = 0.62–50.91, p = 0.13) to 15.52 (95% CI = 2.94–82.38, p = 0.001) by β-catenin overexpression, after adjusting for confounding factors. In conclusion, the present study suggests that cisplatin-based adjuvant chemotherapy needs to be carefully applied to early stage NSCLC patients with overexpressed β-catenin in combination with reduced NME1 expression.

Targeting Multiple Signaling Pathways in Cancer: The Rutin Therapeutic Approach

Multiple dysregulated signaling pathways are implicated in the pathogenesis of cancer. The conventional therapies used in cancer prevention/treatment suffer from low efficacy, considerable toxicity, and high cost. Hence, the discovery and development of novel multi-targeted agents to attenuate the dysregulated signaling in cancer is of great importance. In recent decades, phytochemicals from dietary and medicinal plants have been successfully introduced as alternative anticancer agents due to their ability to modulate numerous oncogenic and oncosuppressive signaling pathways. Rutin (also known as rutoside, quercetin-3-O-rutinoside and sophorin) is an active plant-derived flavonoid that is widely distributed in various vegetables, fruits, and medicinal plants, including asparagus, buckwheat, apricots, apples, cherries, grapes, grapefruit, plums, oranges, and tea. Rutin has been shown to target various inflammatory, apoptotic, autophagic, and angiogenic signaling mediators, including nuclear factor-κB, tumor necrosis factor-α, interleukins, light chain 3/Beclin, B cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein, caspases, and vascular endothelial growth factor. A comprehensive and critical analysis of the anticancer potential of rutin and associated molecular targets amongst various cancer types has not been performed previously. Accordingly, the purpose of this review is to present an up-to-date and critical evaluation of multiple cellular and molecular mechanisms through which the anticancer effects of rutin are known to be exerted. The current challenges and limitations as well as future directions of research are also discussed.

Calcium Sensing Receptor Inhibits Growth of Human Lung Adenocarcinoma Possibly via the GSK3β/Cyclin D1 Pathway

The effect of calcium sensing receptor (CaSR) on tumor cell proliferation has been studied in several human cancers, and great discrepancies were found in different tumors. However, the role of CaSR in lung adenocarcinomas (LUADs) is not clear. Therefore, we investigated the function of CaSR on regulating the growth of human LUAD and its possible mechanism. The expression of CaSR protein and its relationship with pathological parameters were examined in paraffin sections from 51 LUAD patients, by immunohistochemistry. The results showed that CasR expression was negatively correlated with the Ki-67 index as well as the grade of malignancy in LUAD. Further, CaSR demonstrated an in vitro inhibitory effect on the proliferation of human LUAD A549 cells by regulating CaSR activity with agonist cinacalcet, antagonist NPS2143, or shRNA-CaSR transfection. Tumor xenograft models also verified the in vivo proliferation-inhibiting role of CaSR by subcutaneous injecting A549 cells into nude mice with or without changes of CaSR activity. Molecularly, Western blotting showed that CaSR positively regulated the activity of glycogen synthase kinase 3β (GSK3β), followed by the downregulation of Cyclin D1. We used the dominant negative mutant and the constitutively active mutant plasmid of GSK3β to alter GSK3β activity. Our functional experiments showed that the proliferation-inhibition of CaSR was suppressed by the inactivation of GSK3β and enhanced by the activation of GSK3β. These results suggested that CaSR played a proliferation-inhibiting role in LUAD, at least partially by regulating the GSK3β/Cyclin D1 pathway.

Long Non-Coding RNA SPRY4-IT1 Reverses Cisplatin Resistance by Downregulating MPZL-1 via Suppressing EMT in NSCLC

PURPOSE

Long non-coding RNA (lncRNA) SPRY4 intronic transcript 1 (SPRY4-IT1) is reported to play important roles in the occurrence and development of many tumors. However, the possible role of SPRY4-IT1 in cisplatin (DDP) resistance of non-small-cell lung cancer (NSCLC) remains unclear. The aim of this study is to investigate the functions and molecular mechanisms underlying SPRY4-IT1 of cisplatin resistance in NSCLC.

METHODS

Expression of SPRY4-IT1 was analyzed in A549 and cisplatin-resistant A549/DDP cell lines by quantitative real-time polymerase chain reaction (RT-qPCR). Overexpression techniques were applied to investigate the biological functions of SPRY4-IT1 in cisplatin-resistant A549/DDP cells. The effects of SPRY4-IT1 on proliferation and apoptosis were evaluated using cell counting kit-8 (CCK8) assays, colony formation assay and flow-cytometric analysis. The expressions of epithelial-mesenchymal transition (EMT)-associated proteins, including E-cadherin and Vimentin, were detected by Western blot. Microarray analysis was performed to identify the putative targets of SPRY4-IT1, which were further verified by Western blotting and RT-qPCR. A549/DDP cells transfected with pCDNA-SPRY4-IT1 were injected into nude mice in order to verify the effect of SPRY4-IT1 on cisplatin resistance in vivo.

RESULTS

The present study demonstrated that SPRY4-IT1 expression was decreased in A549/DDP cells compared with parental A549 cells. Upregulation of SPRY4-IT1 suppressed cell proliferation and caused apoptosis of A549/DDP cells both in vitro and in vivo. MPZL-1 was negatively regulated by SPRY4-IT1. Furthermore, upregulation of SPRY4-IT1 and downregulation of MPZL-1 could suppress epithelial-mesenchymal transition (EMT), which was characterized by increased E-cadherin expression and decreased Vimentin expression.

CONCLUSION

Upregulation of SPRY4-IT1 reversed the cisplatin-resistant phenotype of NSCLC partially by downregulating MPZL-1 via inhibiting EMT process.

Propofol Improves Sensitivity of Lung Cancer Cells to Cisplatin and Its Mechanism

BACKGROUND Cisplatin (cis-diamminedichloroplatinum, DDP) resistance is identified as the primary obstacle during lung cancer treatment, while DDP resistance is exist extensively. This report was to investigate the roles of propofol in lung cancer cells tolerance to DDP and the potential mechanisms. MATERIAL AND METHODS A549 and A549/DDP cells were treated with DDP for 48 hours, and cell proliferation suppression rate was detected by MTT (thiazolyl blue tetrazolium bromide) assay and half maximal inhibitory concentration (IC₅₀) of DDP to lung cancer cells was calculated. Besides, cell proliferation and apoptosis were determined by MTT assay and flow cytometry assay respectively in propofol-treated A549/DDP and A549 cells. Furthermore, we performed MTT assay to determine the influence of propofol on the sensitivity of lung cancer cells to DDP. RESULTS The results demonstrated that the IC₅₀ of DDP to A549 cells was lower than that in A549/DDP cells. Propofol dramatically inhibited cell proliferation and promoted cell apoptosis of A549/DDP and A549 cells. In addition, propofol significantly improved the anti-proliferative impact of DDP in A549/DDP and A549 cells, and the value of IC₅₀ for DDP in the A549/DDP and A549 cells were decreased after propofol treatment compare to the control group. Moreover, propofol inhibited the Wnt/ß-catenin pathway in a dose-dependent manner in both A549/DDP and A549 cells. CONCLUSIONS Our report indicated that propofol could control lung cancer cell proliferation and apoptosis, and stimulated the suppression function of DDP on lung cancer cell multiplication via the Wnt/ß-catenin signaling pathway, and also provided a new treatment for DDP tolerance to cure lung cancer in clinical.

Wnt Signaling and Drug Resistance in Cancer

Wnts are secreted proteins that bind to cell surface receptors to activate downstream signaling cascades. Normal Wnt signaling plays key roles in embryonic development and adult tissue homeostasis. The secretion of Wnt ligands, the turnover of Wnt receptors, and the signaling transduction are tightly regulated and fine-tuned to keep the signaling output "just right." Hyperactivated Wnt signaling due to recurrent genetic alterations drives several human cancers. Elevated Wnt signaling also confers resistance to multiple conventional and targeted cancer therapies through diverse mechanisms including maintaining the cancer stem cell population, enhancing DNA damage repair, facilitating transcriptional plasticity, and promoting immune evasion. Different classes of Wnt signaling inhibitors targeting key nodes of the pathway have been developed and show efficacy in treating Wnt-driven cancers and subverting Wnt-mediated therapy resistance in preclinical studies. Several of these inhibitors have advanced to clinical trials, both singly and in combination with other existing US Food and Drug Administration-approved anti-cancer modalities. In the near future, pharmacological inhibition of Wnt signaling may be a real choice for patients with cancer. SIGNIFICANCE STATEMENT: The latest insights in Wnt signaling, ranging from basic biology to therapeutic implications in cancer, are reviewed. Recent studies extend understanding of this ancient signaling pathway and describe the development and improvement of anti-Wnt therapeutic modalities for cancer.

circ_0003418 Inhibits Tumorigenesis And Cisplatin Chemoresistance Through Wnt/β-Catenin Pathway In Hepatocellular Carcinoma

Background

Accumulating evidences indicate that circRNAs play important roles in the progression and chemoresistance of human cancers. The present study is designated for researching the roles of circ_0003418 in hepatocellular carcinoma (HCC).

Methods

We detected the expression profile of circ_0003418 in human HCC tissues and cell lines by quantitative real-time-PCR assays. CCK-8 assay, transwell migration assay, transwell invasion assay and drug-sensitivity analysis were carried out to estimate the effects of circ_0003418 on HCC cells' proliferation, migration, invasion and resistance to cisplatin, respectively. Mouse xenograft model was conducted to monitor the role of circ_0003418 in cisplatin resistance in vivo. Western blotting was performed to explore the changes of the Wnt/β-catenin pathway after knockdown of circ_0003418. The rescue experiment was carried out to explore circ_0003418-activated biological functions through Wnt/β-catenin pathway.

Results

The expression level of circ_0003418 was downregulated in HCC tissues and cell lines, and the level correlated with tumor size, TNM stage and HBsAg level in HCC patients. circ_0003418 knockdown promoted HCC cells' proliferation, migration, and invasion. Additionally, suppression of circ_0003418 enhanced cisplatin resistance of HCC cells in vivo and vitro. Knockdown of circ_0003418 activated the Wnt/β-catenin signalling pathway in HCC cells. The effect of circ-0003418 on sensitivity of HCC cells to cisplatin was reversed after inhibition of Wnt/β-catenin pathway.

Conclusion

circ-0003418 exerts an antitumorigenic role in HCC and advances the sensitivity of HCC cells to cisplatin by restraining the Wnt/β-catenin pathway. Thus, circ-0003418 may represent a novel biomarker and provide us a new strategy for the treatment of HCC.

The CK2 inhibitor CX4945 reverses cisplatin resistance in the A549/DDP human lung adenocarcinoma cell line

Lung cancer negatively impacts global health, and the incidence of non-small cell lung cancer (NSCLC) is highest among all forms of lung cancer. Chemotherapy failure mainly occurs due to drug resistance; however, the associated molecular mechanism remains unclear. Casein kinase II (CK2), which plays important roles in the occurrence, development and metastasis of many tumours, regulates Wnt signaling by modulating β-catenin expression. In the present study the effects of the CK2 inhibitor, CX4945 on cisplatin [or cis-diamminedichloroplatinum (II); (DDP)]-resistant A549 cells (A549/DDP) were investigated to elucidate the underlying molecular mechanism. A549/DDP cells were divided into four groups (blank control, CX4945, cisplatin and CX4945+cisplatin). Cisplatin resistance was 5.16-fold greater in A549/DDP cells compared with that in A549 cells, with an optimal cisplatin concentration of 5 µg/ml. Moreover, levels of CK2, dishevelled-2 (DVL-2) phosphorylated (p) at Ser143 (p-DVL-2^Ser143), and major Wnt-signaling proteins were significantly higher in A549/DDP cells compared with that in A549 cells (P<0.05), with these levels further increased following cisplatin treatment (P<0.05), whereas these levels significantly decreased in A549 cells after cisplatin treatment (P<0.05). Additionally, multidrug-resistance-associated protein 1 and lung resistance protein expression was significantly higher in A549/DDP cells compared with that in A549 cells (P<0.05), with these levels increasing further in A549/DDP (P<0.05) but not A549 cells upon cisplatin treatment (P>0.05). In addition, reduced expression of resistance proteins in A549/DDP cells was accompanied by a decline in the 50% growth inhibition after CX4945 pre-treatment. Furthermore, levels of p-DVL-2^Ser143 and major Wnt-signaling proteins decreased significantly after treatment of A549/DDP cells with CX4945+cisplatin, whereas DVL-2 and p-DVL-2^Thr224 levels remained unchanged. Additionally, significant elevations in apoptosis rates in the CX4945+cisplatin group relative to the control and cisplatin-only groups, was observed (P<0.001). These results suggested that inhibiting Wnt/β-catenin signaling with CX4945, which attenuates levels of drug-resistance-associated proteins and induces apoptosis, might reverse cisplatin resistance in NSCLC.

Urolithin B suppresses tumor growth in hepatocellular carcinoma through inducing the inactivation of Wnt/β-catenin signaling

Consumption of dietary ellagitannins (ETs) has been proven to benefit multiple chronic health disorders including cancers and cardiovascular diseases. Urolithins, gut microbiota metabolites derived from ETs, are considered as the molecules responsible for these health effects. Previous studies have demonstrated that urolithins exhibit antiproliferative effects on prostate, breast, and colon cancers. However, as for hepatocellular carcinoma (HCC), it remains elusive. Herein, we aim to investigate the function of urolithin B (UB), a member of urolithins family, in HCC. The effects of UB on cell viability, cell cycle and apoptosis were evaluated in HCC cells, and we found UB could inhibit the proliferation of HCC cells, which resulted from cell cycle arrest and apoptosis. Furthermore, UB could increase phosphorylated β-catenin expression and block its translocation from nuclear to cytoplasm, thus inducing the inactivation of Wnt/β-catenin signaling. Using a xenograft mice model, UB was found to suppress tumor growth in vivo. In conclusion, our data demonstrated that UB could inhibit the proliferation of HCC cells in vitro and in vivo via inactivating Wnt/β-catenin signaling, suggesting UB could be a promising candidate in the development of anticancer drugs targeting HCC.

Characterisation of resistance mechanisms developed by basal cell carcinoma cells in response to repeated cycles of Photodynamic Therapy

Photodynamic Therapy (PDT) with methyl-aminolevulinate acid (MAL-PDT) is being used for the treatment of Basal cell carcinoma (BCC), but recurrences have been reported. In this work, we have evaluated resistance mechanisms to MAL-PDT developed by three BCC cell lines (ASZ, BSZ and CSZ), derived from mice on a ptch+/- background and with or without p53 expression, subjected to 10 cycles of PDT (10thG). The resistant populations showed mesenchymal-like structure and diminished proliferative capacity and size compared to the parental (P) cells. The resistance was dependent on the production of the endogenous photosensitiser protoporphyrin IX in the CSZ cell line and on its cellular localisation in ASZ and BSZ cells. Moreover, resistant cells expressing the p53 gene presented lower proliferation rate and increased expression levels of N-cadherin and Gsk3β (a component of the Wnt/β-catenin pathway) than P cells. In contrast, 10thG cells lacking the p53 gene showed lower levels of expression of Gsk3β in the cytoplasm and of E-cadherin and β-catenin in the membrane. In addition, resistant cells presented higher tumorigenic ability in immunosuppressed mice. Altogether, these results shed light on resistance mechanisms of BCC to PDT and may help to improve the use of this therapeutic approach.

Overexpressed C14orf166 associates with disease progression and poor prognosis in non-small-cell lung cancer

Chromosome 14 ORF 166 (C14orf166), a protein involved in the regulation of RNA transcription and translation, has been reported to possess the potency to promote tumorigenesis; however, the role of C14orf166 in non-small-cell lung cancer (NSCLC) remains unknown. The purpose of the present study was to assess C14orf166 expression and its clinical significance in NSCLC. Immunohistochemical staining, quantitative real-time PCR (qRT-PCR), and Western blotting were used to detect the C14orf166 protein and mRNA expression levels in NSCLC tissues compared with adjacent normal tissues, as well as in NSCLC cells lines compared with normal human bronchial epithelial cells (HBE). Then, the correlations between the C14orf166 expression levels and the clinicopathological features of NSCLC were analyzed. Additionally, the Cox proportional hazard model was used to evaluate the prognostic significance of C14orf166. We found that C14orf166 expression increased in carcinoma tissues compared with their adjacent normal tissues at the protein (P<0.001) and mRNA levels (P<0.001). High expression of C14orf166 was significantly associated with the T stage (P=0.006), lymph node metastasis (P=0.001), advanced TNM stage (P<0.001), and chemotherapy (P<0.001). Moreover, according to the survival analysis, patients with overexpressed C14orf166 were inclined to experience a shorter overall survival and disease-free survival time (P<0.001). Multivariate COX analysis implied that C14orf166 was an independent prognostic biomarker. Taken together, our findings indicate that the overexpression of C14orf166 may contribute to the disease progression of NSCLC, represent a novel prognostic predictor and help high-risk patients make better decisions for subsequent therapy.

Chemotherapy-Induced Long Non-coding RNA 1 Promotes Metastasis and Chemo-Resistance of TSCC via the Wnt/β-Catenin Signaling Pathway

Increasing evidence has shown that chemo-resistance is related to the process of epithelial-mesenchymal transition (EMT) and increased invasiveness by tongue squamous cell carcinoma (TSCC) cells. Long non-coding RNAs (lncRNAs) play pivotal roles in tumor metastasis and progression. However, the roles and mechanisms of lncRNAs in cisplatin-resistance-induced EMT and metastasis are not well understood. In this study, a chemotherapy-induced lncRNA 1 (CILA1) was discovered by using microarrays and was functionally identified as a regulator of chemo-sensitivity in TSCC cells. Upregulation of CILA1 promotes EMT, invasiveness, and chemo-resistance in TSCC cells, whereas the inhibition of CILA1 expression induces mesenchymal-epithelial transition (MET) and chemo-sensitivity, and inhibits the invasiveness of cisplatin-resistant cells both in vitro and in vivo. We also found that CILA1 exerts its functions via the activation of the Wnt/β-catenin signaling pathway. High CILA1 expression levels and low levels of phosphorylated β-catenin were closely associated with cisplatin resistance and advanced disease stage, and were predictors of poor prognosis in TSCC patients. These findings provided a new biomarker for the chemo-sensitivity of TSCC tumors and a therapeutic target for TSCC treatment.

Cisplatin suppresses proliferation, migration and invasion of nasopharyngeal carcinoma cells in vitro by repressing the Wnt/β-catenin/Endothelin-1 axis via activating B cell translocation gene 1

PURPOSE

Nasopharyngeal carcinoma (NPC) is one of the most commonly diagnosed cancers worldwide with significantly high prevalence in Southern China. Chemoprevention of cancer with alkylating agent compounds could potentially reverse, suppress, or prevent cancer progression. Cisplatin (CIS) is an antineoplastic or cytotoxic platinum-based drug used for chemotherapy of different types of human cancers such as NPC. Nevertheless, the effects of CIS on the migration and invasion of human NPC cells and the underlying molecular mechanisms have not yet been fully scrutinized.

METHODS

In this work, we tested the effect of CIS on the proliferation, migration and invasion of NPC cells. The results exhibited that this drug exerts remarkable inhibitory effects on the proliferation, migration and invasion of NPC cells in a dose-dependent manner. Western blotting and real time RT-PCR were used for expression analyses.

RESULTS

We found that CIS treatment led to a dose-dependent inhibition of Endothelin-1 (ET1) expression, at protein as well as mRNA levels in NPC cells. CIS was also found to activate the expression of BTG1 in NPC cells. Moreover, mechanistic analyses revealed that CIS increased the expression of B cell translocation gene 1 (BTG1) to suppress the expression of ET1. Furthermore, we show that ET1 could not be induced in CIS-resistant cells with suppressed BTG1 expression, and subsequently demote the proliferation, migration and invasion of NPC cells.

CONCLUSIONS

These findings provided compelling evidence of the role of CIS in suppressing NPC metastasis and its underlying molecular mechanisms.

Crosstalk between long non-coding RNAs and Wnt/β-catenin signalling in cancer

Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts in the human genome which perform crucial functions in diverse biological processes. The abnormal expression of some lncRNAs has been found in tumorigenesis, development and therapy resistance of cancers. They may act as oncogenes or tumour suppressors and can be used as diagnostic or prognostic markers, prompting their therapeutic potentials in cancer treatments. Studies have indicated that many lncRNAs are involved in the regulation of several signal pathways, including Wnt/β-catenin signalling pathway, which has been reported to play a significant role in regulating embryogenesis, cell proliferation and controlling tumour biology. Emerging evidences have suggested that lncRNAs can interact with several components of the Wnt/β-catenin signalling pathway to regulate the expression of Wnt target genes in cancer. Moreover, the expression of lncRNAs can also be influenced by the pathway. Nevertheless, Wnt/β-catenin signalling pathway-related lncRNAs and their interactions in cancer are not systematically analysed before. Considering these, this review emphasized the associations between lncRNAs and Wnt/β-catenin signalling pathway in cancer initiation, progression and their therapeutic influence. We also provided an overview on characteristics of lncRNAs and Wnt/β-catenin signalling pathway and discussed their functions in tumour biology. Finally, targeting lncRNAs or/and molecules associated with the Wnt/β-catenin signalling pathway may be a feasible therapeutic method in the future.

Effect of microRNA-128 on cisplatin resistance of glioma SHG-44 cells by targeting JAG1

This current study intends to investigate the effect of microRNA-128 (miR-128) on cisplatin (DDP) resistance in glioma SHG-44 cells. SHG-44/DDP cells were transfected with miR-128 antisense oligonucleotide (ASO) and assigned into blank, resistance, NC, anti-miR-128, miR-128 mimic, si-JAG1, and anti-miR-128 + si-JAG1 groups. qRT-PCR and Western blotting were employed for determining expression of miR-128, JAG1, Bax and Bcl-2. MTT assay, Giemsa staining, and flow cytometry were applied to detect DDP resistance, cellular morphology, and cell cycle, respectively. JAG1 is targeted and negatively regulated by miR-128. In in vitro experiments, compared with the blank group, the rest groups exhibited declined miR-28 and Bax expression, lowered cell inhibition rate and apoptosis rate, but elevated JAG1 and Bcl-2 expression with cells arrested in the S phase. Compared with the resistance group, the anti-miR-128 group showed decreasedBax expression along with a lowered cell inhibition rate and apoptosis rate, but increased JAG1 and Bcl-2 expression with reduced cells arrested in the S phase; while the miR-128 mimic group showed an opposite trend; the si-JAG1 group showed decreased Bcl-2 expression and reduced cells in the S phase. In in vivo experiments, compared with the resistance group, the tumor growth rate, tumor volume, and weight as well as JAG1 expression accelerated in the anti-miR-128 group; whereas the miR-128 mimic and si-JAG1 groups exhibited an opposite trend. Our findings demonstrated that miR-128 ASO transfection might down-regulate the expression of miR-128 in SHG-44/DDP and up-regulate the DDP resistance in SHG-44/DDP cells, providing a potential treatment target for glioma.

GSK-3β inhibitor 6-bromo-indirubin-3'-oxime promotes both adhesive activity and drug resistance in colorectal cancer cells

Multi-targets inhibitor 6-bromo-indirubin-3'-oxime (BIO) has diverse biological effects on cancer cells. The key component of the β-catenin destruction complex glycogen synthase kinase 3β (GSK-3β), one of the major target for BIO, polyubiquitination and degradation of the main oncoprotein β-catenin in colorectal cancer (CRC). In the present study, we evaluated the effect of BIO on drug resistance and biological properties of CRC cells. Whole-genome transcriptional profiling revealed that differentially expressed genes were mainly centered on well-characterized signaling pathways including stem cell, cell adhesion and cell growth in BIO-treated CRC cells. BIO treatment downregulated migration and invasion abilities of CRC cells, accompanying with MMP-9 downregulated and E-cadherin upregulated CRC cells. BIO treatment decreased apoptosis induced by 5-Fu/DDP in CRC SW480 cells. In addition, BIO treatment reversed the 5-Fu-induced CD133+ cell downregulation trend in CRC SW620 cells. After incubation with BIO, the expression levels of EpCAM, TERT and DCAMKL-1 proteins were upregulated in CRC cells. BIO treatment downregulated the activity of GSK-3β, upregulated and transported β-catenin to the nucleus in CRC cells. Our findings reveal that BIO treatment upregulated stemness, adhesive and chemoresistance of CRC cells. GSK-3β inhibition and WNT/β-catenin activation by BIO, may partly result in the biological behavior alterations in CRC cells.

MiR-410 induces stemness by inhibiting Gsk3β but upregulating β-catenin in non-small cells lung cancer

Our previous research indicated miR-410 played a critical role in promoting the tumorigenesis and development of NSCLC (non-small cells lung cancer). MiR-410 has been recently reported to be crucial for development and differentiation of embryonic stem cells. But it remains elusive whether miR-410 stimulates the stemness of cancer until now. Herein, we identify miR-410 induces the stemness and is associated with the progression of NSCLC. We demonstrate miR-410 increases the levels of stem cells marker Sox2, Oct4, Nanog, CXCR4 as well as lung cancer stem cells surface marker CD44 and CD166. MiR-410 promotes stem cells-like properties such as proliferation, sphere formation, metastasis and chemoresistance. Moreover, Gsk3β is directly targeted and post-transcriptionally downregulated by miR-410. Also, the expression levels of miR-410 and Gsk3β may be correlated to clinicopathological differentiation in NSCLC tumor specimens. Additionally, we demonstrate miR-410 induces stemness through inhibiting Gsk3β but increasing Sox2, Oct4, Nanog and CXCR4, which binds to β-catenin signaling. In conclusion, our findings identify the miR-410/Gsk3β/β-catenin signaling axis is a novel molecular circuit in inducing stemness of NSCLC.

Metastasis-associated in colon cancer 1: A promising biomarker for the metastasis and prognosis of colorectal cancer

Colorectal cancer (CRC) is the fourth most frequent type of malignancy in the world. Metastasis accounts for >90% mortalities in patients with CRC. The metastasis-associated in colon cancer 1 (MACC1) gene has been identified as a novel biomarker for the prediction of metastasis and disease prognosis, particularly for patients with early-stage disease. Previous clinical studies demonstrated that MACC1 expression and polymorphisms in CRC tissues were indicators of metastasis, and that circulating transcripts in plasma were also significantly associated with the survival of patients. The present review describes the use of MACC1 beyond its utility in the clinic. By elucidating the upstream and downstream signal pathways of MACC1, the well-known mechanisms of MACC1-mediated cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) are summarized, as well as the potential signaling pathways. Furthermore, the underlying mechanisms by which the overexpression of MACC1 causes cisplatin resistance are emphasized.

Knockdown of Upregulated Gene 11 (URG11) Inhibits Proliferation, Invasion, and β-Catenin Expression in Non-Small Cell Lung Cancer Cells

Upregulated gene 11 (URG11), a new gene upregulated by hepatitis B virus X protein, was found to be involved in the development and progression of several tumors. However, the role of URG11 in human non-small cell lung cancer (NSCLC) has not yet been determined. Therefore, the aim of the present study was to explore the role of URG11 in human NSCLC. Our results found that URG11 was highly expressed in human NSCLC tissues compared with matched normal lung tissues, and higher levels were found in NSCLC cell lines in comparison to the normal lung cell line. Moreover, we also found that knockdown of URG11 significantly inhibited proliferation, migration/invasion of NSCLC cells, as well as suppressed tumor growth in vivo. Furthermore, knockdown of URG11 suppressed the expression of β-catenin, c-Myc, and cyclin D1 in NSCLC cells. Taken together, the study reported here provided evidence that URG11 downregulation suppresses proliferation, invasion, and β-catenin expression in NSCLC cells. Thus, URG11 may be a novel potential therapeutic target for NSCLC.

Expression and clinical significance of C14orf166 in esophageal squamous cell carcinoma

C14orf166, a 28 kD protein regulating RNA transcription and translation, may serve a critical role in oncogenesis. The aim of the current study was to explore the association between C14orf166 expression and esophageal squamous cell carcinoma (ESCC) and to draw attention to the association between C14orf166 and the initiation, progression and prognosis of ESCC. C14orf166 expression in ESCC and paired normal tissues was detected by immunohistochemical staining, western blotting and reverse transcription-quantitative polymerase chain reaction, and the association between C14orf166 expression and clinicopathological characters of ESCC was analyzed. Survival analysis was used to assess the prognostic significance of C14orf166 and it was observed that C14orf166 expression was higher in the ESCC tissues when compared with adjacent non-cancerous tissues at protein (P<0.001) and mRNA levels (P<0.001). There was a significant difference in T stage, lymph node metastasis and TNM stage in patients categorized according to different C14orf166 expression levels. The overexpression of C14orf166 was associated with a shorter overall survival and disease-free survival, and multivariate analysis indicated that C14orf166 was an independent prognostic indicator. The present study indicates that the expression of C14orf166 is elevated in ESCC, and is potentially a valuable prognostic predictor for ESCC.

Wnt5a Increases Properties of Lung Cancer Stem Cells and Resistance to Cisplatin through Activation of Wnt5a/PKC Signaling Pathway

The development of chemoresistance to cisplatin regimens causes a poor prognosis in patients with advanced NSCLC. The role of noncanonical Wnt signaling in the regulation of properties of lung cancer stem cells and chemoresistance was interrogated, by accessing capacities of cell proliferation, migration, invasion, and clonogenicity as well as the apoptosis in A549 cell lines and cisplatin-resistant A549 cells treated with Wnt5a conditional medium or protein kinase C (PKC) inhibitor GF109203X. Results showed that the noncanonical Wnt signaling ligand, Wnt5a, could promote the proliferation, migration, invasion, and colony formation in A549 lung adenocarcinoma cells and cisplatin-resistant A549/DDP cells and increase the fraction of ALDH-positive cell in A549/DDP cells. An exposure of cells to Wnt5a led to a significant reduction of A549/DDP cell apoptosis but not A549 cells. An addition of GF109203X could both strikingly increase the baseline apoptosis and resensitize the Wnt5a-inhibited cell apoptosis. Interestingly, an inhibition of Wnt/PKC signaling pathway could reduce properties of lung cancer stem cells, promote cell apoptosis, and resensitize cisplatin-resistant cells to cisplatin via a caspase/AIF-dependent pathway. These data thus suggested that the Wnt5a could promote lung cancer cell mobility and cisplatin-resistance through a Wnt/PKC signaling pathway and a blockage of this signaling may be an alternative therapeutic strategy for NSCLC patients with resistance to chemotherapies.

Activation of AIFM2 enhances apoptosis of human lung cancer cells undergoing toxicological stress

Application of cisplatin (DDP) for treating lung cancer is restricted due to its toxicity and lung cancer's drug resistance. In this study, we examined the effect of Jinfukang (JFK), an effective herbal medicine against lung cancer, on DDP-induced cytotoxicity in lung cancer cells. Morphologically, we observed that JFK increases DDP-induced pro-apoptosis in A549 cells in a synergistic manner. Transcriptome profiling analysis indicated that the combination of JFK and DDP regulates genes involved in apoptosis-related signaling pathways. Moreover, we found that the combination of JFK and DDP produces synergistic pro-apoptosis effect in other lung cancer cell lines, such as NCI-H1975, NCI-H1650, and NCI-H2228. Particularly, we demonstrated that AIFM2 is activated by the combined treatment of JFK and DDP and partially mediates the synergistic pro-apoptosis effect. Collectively, this study not only offered the first evidence that JFK promotes DDP-induced cytotoxicity, and activation of AIFM2 enhances apoptosis of human lung cancer cells undergoing toxicological stress, but also provided a novel insight for improving cytotoxicity by combining JFK with DDP to treat lung cancer cells.

Anticancer effect of 20(S)-ginsenoside Rh2 on HepG2 liver carcinoma cells: Activating GSK-3β and degrading β-catenin

20(S)-ginsenoside Rh2 [(S)Rh2] possesses potential to prevent cancer in vitro as well as in vivo, but the underlying mechanism is still unknown. First, we infected HepG2 cells with lentivirus which carries β‑catenin. We detected the pharmacological effects of (S)Rh2 on HepG2 and HepG2‑β‑catenin cells and found that the IC50 of (S)Rh2 exposure on HepG2-β-catenin cells was higher than HepG2 cells. Flow cytometry (FCM) indicated that (S)Rh2 could be arrested in G0/G1 phase and induce early apoptosis in HepG2 and HepG2‑β‑catenin cells. Second, ELISA kit was used to check the activity of glycogen synthase kinase‑3β (GSK‑3β), which was upregulated by (S)Rh2. GSK‑3β inhibitor BIO, was used to verify that (S)Rh2 activated GSK‑3β. PCR and western blotting results indicated that (S)Rh2 could degrade the expression of β‑catenin, which combined with TCF in the nucleus and activate transcription of Wnt target genes, such as Bax, Bcl‑2, cyclin D1, MMP3, which were checked by chromatin immunoprecipitation (ChIP), PCR and western blotting. The results showed that the expression of Bax mRNA and proteins increased, while the cyclin D1, Bcl‑2, MMP3 mRNA and proteins were downregulated in HepG2 and HepG2‑β‑catenin cells which was induced by (S)Rh2. By contrast, with the HepG2-β-catenin + (S)Rh2 group, the expression of other mRNA and proteins in HepG2 + (S)Rh2 group changed significantly. In vivo, experiments were performed using a nude mouse xenograft model to investigate the (S)Rh2 effect. So these results suggested that (S)Rh2 could suppress proliferation, promote apoptosis and inhibit metastasis of HepG2, decrease weight of tumor by downregulating β‑catenin through activating GSK‑3β and the pharmacological effect of (S)Rh2 on HepG2 cells might be weakened by overexpression of β‑catenin.

Wnt signaling as potential therapeutic target in lung cancer

INTRODUCTION

Wingless-type (Wnt) signaling is tightly regulated at multiple cellular levels and is dysregulated in lung cancer. Therefore, it offers therapeutic targets for developing novel agents for lung cancer treatment.

AREAS COVERED

In this article, we discuss the role of the Wnt signaling pathway in lung cancer, highlighting the aberrant activation of Wnt in lung cancer stem cells and its implication in resistance to radiotherapy, chemotherapy and targeted therapy. We also expound the regulatory roles of microRNAs in Wnt signaling, as well as the potential of the Wnt pathway to provide biomarkers and therapeutic targets in lung cancer. The potential use of small molecule and biological inhibitors targeting the Wnt pathway for lung cancer therapy and prevention is also discussed.

EXPERT OPINION

Wnt signaling plays an important role in the development and metastasis of lung cancer; the pathway provides targets to develop agents towards for cancer prevention and therapy. A number of clinical trials have shown the effectiveness of Wnt pathway inhibitors in epithelial tumors. However, the side effects should be considered. Nevertheless, the results from clinical studies suggest that inhibitors targeting the Wnt signaling show promise against lung cancer.

β-Catenin signaling pathway regulates cisplatin resistance in lung adenocarcinoma cells by upregulating Bcl-xl

The Wnt/β-catenin signaling pathway has been reported to regulate cisplatin resistance in several types of cancer cell. The present study aimed to investigate the role and underlying mechanism of Wnt/β-catenin signaling in cisplatin resistance of lung adenocarcinoma cells. Wild-type and cisplatin-resistant A549 human lung adenocarcinoma cells (A549/WT and A549/CDDP, respectively) were cultured in vitro and exposed to different cisplatin concentrations. Cells were incubated with 10 mM lithium chloride (LiCl) to activate β-catenin signaling. Cell proliferation was determined using the MTS assay. Cell apoptosis was evaluated using Annexin V/propidium iodide double staining, followed by flow cytometry. β-catenin was knocked down using small interfering RNA (siRNA). The intracellular distribution of β-catenin was determined by immunocytochemistry, and the mRNA and protein expressions of target genes were examined by reverse transcription-quantitative polymerase chain reaction and western zblotting, respectively. β-catenin and B-cell lymphoma-extra large (Bcl-xl) were significantly upregulated in A549/CDDP cells compared with A549/WT cells (P<0.05). LiCl reduced the sensitivity of A549/WT cells to cisplatin (P<0.01); and upregulated, increased phosphorylation (P<0.05) and enhanced nuclear translocation of β-catenin. LiCl also significantly elevated the mRNA and protein expression levels of Bcl-xl (P<0.05). Notably, silencing of β-catenin with siRNA decreased the mRNA and protein expression of Bcl-xl, and sensitized A549/WT cells to cisplatin (P<0.01). The findings of the current study suggest that upregulation of β-catenin signaling may contribute to cisplatin resistance in lung adenocarcinoma cells by upregulating Bcl-xl. Therefore, molecular targeting of Wnt/β-catenin signaling may sensitize lung cancer cells to cisplatin.

Cisplatin-selected resistance is associated with increased motility and stem-like properties via activation of STAT3/Snail axis in atypical teratoid/rhabdoid tumor cells

Atypical teratoid/rhabdoid tumor (ATRT) is a malignant pediatric brain tumor with great recurrence after complete surgery and chemotherapy. Here, we demonstrate that cisplatin treatment selects not only for resistance but also for a more oncogenic phenotype characterized by high self-renewal and invasive capabilities. These phenomena are likely due to STAT3 upregulatoin which occurred simultaneously with higher expression of Snail, an activator of epithelial-mesenchymal transition (EMT), in ATRT-CisR cells. STAT3 knockdown effectively suppressed Snail expression and blocked motility and invasion in ATRT-CisR cells, while overexpressing Snail reversed these effects. Chromatin immunoprecipitation assay indicated that STAT3 directly bound to Snail promoter. Moreover, STAT3 knockdown effectively suppressed cancer stem-like properties, synergistically enhanced the chemotherapeutic effect, and significantly improved survival rate in ATRT-CisR-transplanted immunocompromised mice. Finally, immunohistochemistrical analysis showed that STAT3 and Snail were coexpressed at high levels in recurrent ATRT tissues. Thus, the STAT3/Snail pathway plays an important role in oncogenic resistance, rendering cells not only drug-resistant but also increasingly oncogenic (invasion, EMT and recurrence). Therefore, the STAT3/Snail could be a target for ATRT treatment.

Phenotype plasticity rather than repopulation from CD90/CK14+ cancer stem cells leads to cisplatin resistance of urothelial carcinoma cell lines

BACKGROUND

Tumour heterogeneity and resistance to systemic treatment in urothelial carcinoma (UC) may arise from cancer stem cells (CSC). A recent model describes cellular differentiation states within UC based on corresponding expression of surface markers (CD) and cytokeratins (CK) with CD90 and CK14 positive cells representing the least differentiated and most tumourigenic population. Based on the fact that this population is postulated to constitute CSCs and the origin of cisplatin resistance, we enriched urothelial carcinoma cell lines (UCCs) for CD90 and studied the tumour-initiating potential of these separated cells in vitro.

METHODS

Magnetic- and fluorescence-activated- cell sorting were used for separation of CD90(+) and CD90(-) UCCs. Distribution of cell surface markers CD90, CD44, and CD49f and cytokeratins CK14, CK5, and CK20 as well as the effects of short- and long-term treatment with cisplatin were assessed in vitro and measured by qRT-PCR, immunocytochemistry, reporter assay and flow cytometry in 11 UCCs.

RESULTS

We observed cell populations with surface markers according to those reported in tumour xenografts. However, expression of cytokeratins did not concord regularly with that of the surface markers. In particular, expression of CD90 and CK14 diverged during enrichment of CD90(+) cells by immunomagnetic sorting or following cisplatin treatment. Enriched CD90(+) cells did not exhibit CSC-like characteristics like enhanced clonogenicity and cisplatin resistance. Moreover, selection of cisplatin-resistant sublines by long-term drug treatment did not result in enrichment of CD90(+) cells. Rather, these sublines displayed significant phenotypic plasticity expressing EMT markers, an altered pattern of CKs, and WNT-pathway target genes.

CONCLUSIONS

Our findings indicate that the correspondence between CD surface markers and cytokeratins reported in xenografts is not maintained in commonly used UCCs and that CD90 may not be a stable marker of CSC in UC. Moreover, UCCs cells are capable of substantial phenotypic plasticity that may significantly contribute to the emergence of cisplatin resistance.

DKK1 is a potential novel mediator of cisplatin-refractoriness in non-small cell lung cancer cell lines

Background

Platinum compounds are the mainstay of chemotherapy for lung cancer. Unfortunately treatment failure remains a critical issue since about 60 % of all non-small cell lung cancer (NSCLC) patients display intrinsic platinum resistance.

Methods

We analyzed global gene expression profiles of NSCLC clones surviving a pulse treatment with cisplatin and mapped deregulated signaling networks in silico by Ingenuity Pathway Analysis (IPA). Further validation was done using siRNA.

Results

The pooled cisplatin-surviving NSCLC clones from each of the biological replicates demonstrated heterogeneous gene expression patterns both in terms of the number and the identity of the altered genes. Genes involved in Wnt signaling pathway (Dickkopf-1, DKK1), DNA repair machinery (XRCC2) and cell-cell/cell-matrix interaction (FMN1, LGALS9) were among the top deregulated genes by microarray in these replicates and were validated by q-RT-PCR. We focused on DKK1 which previously was reported to be overexpressed in NSCLC patients. IPA network analysis revealed coordinate up-regulation of several DKK1 transcriptional regulators (TCF4, EZH2, DNAJB6 and HDAC2) in cisplatin-surviving clones from that biological replicate. Knockdown of DKK1 by siRNA sensitized for cisplatin in two different NSCLC cell lines and in ovarian A2780 cells, but not in the A2780 cis subline made resistant to cisplatin by chronic exposure, suggesting a role of DKK1 in intrinsic but not acquired platinum refractoriness.

Conclusions

We identified DKK1 as a possible marker of a cisplatin-refractory phenotype and as a potential novel therapeutic target to improve platinum response of NSCLC cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1635-9) contains supplementary material, which is available to authorized users.

ERK/GSK3β signaling is involved in atractylenolide I-induced apoptosis and cell cycle arrest in melanoma cells

Novel agents need to be developed to overcome the limitations of the current melanoma therapeutics. Atractylenolide I (AT-I) is a sesquiterpene compound isolated from atractylodis macrocephalae rhizoma. Previous findings demonstrated that AT-I exhibited cytotoxic action in melanoma cells. However, the molecular mechanisms of AT‑1's anti-melanoma properties remain to be elucidated. In the present study, the cell cycle-arrest and apoptosis-promoting effects as well as the ERK/GSK3β signaling-related mechanism of action of AT-I were examined. B16 melanoma cells were treated with various concentrations of AT-1 (50, 75 and 100 µM) for 48 or 72 h. Cell cycle and apoptosis were analyzed by flow cytometry. Protein expression levels were detected by western blot analysis. AT-I treatment induced G1 phase arrest, which was accompanied by increased p21 and decreased CDK2 protein expression levels. Apoptosis was observed after AT-I treatment for 72 h, which was accompanied by activated caspase‑3 and ‑8. AT-I treatment significantly decreased phospho-ERK, phospho-GSK3β, c-Jun and increased p53 protein expression levels. Lithium chloride (LiCl, 5 mM), a GSK3β inhibitor, treatment alone did not increase the apoptosis of B16 cells, while pretreatment with LiCl markedly reversed AT-I-induced apoptosis. Additionally, AT-I-induced G1 phase arrest was partially reversed by LiCl pretreatment. In conclusion, ERK/GSK3β signaling was involved in the apoptotic and G1 phase arrest effects of AT-I in melanoma cells.

MicroRNA-26b inhibits cell proliferation and cytokine secretion in human RASF cells via the Wnt/GSK-3β/β-catenin pathway

Background

Rheumatoid arthritis (RA) is a chronic systemic auto- immune disease characterized by joint synovitis. Recent evidence suggests that rheumatoid arthritis synovial fibroblasts (RASFs) promote joint destruction. In this study, we investigated the role of microRNA-26b (miR-26b) in cell proliferation and inflammatory cytokine secretion using patient-derived Rheumatoid arthritis fibroblast-like synoviocyte (RAFLS) to understand pathways influencing rheumatoid arthritis.

Methods

RAFLS were cultured in vitro and transfected with miR-26b mimics (experimental group) and negative sequence (control group). The protein levels of Wnt4, Wnt5ɑ, GSK-3β, CyclinD1, Ser9-GSK-3β and β-catenin were detected by western blot analysis. Tumor Necrosis Factor-ɑ (TNF-ɑ), IL- 1β, and IL-6 levels were quantified by Enzyme-linked Immunosorbent Assay (ELISA). RAFLS proliferation and apoptosis were measured by 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry, respectively.

Results

GSK-3β and CyclinD1 expression levels were lower in miR-26b mimic group compared to Mock group and negative control (NC) group. Conversely, GSK-3β and CyclinD1 expression levels were markedly higher in the miR-26b inhibitor group compared to Mock and NC group (P < 0.05). Transfection of miR-26b mimics significantly increased the, levels of Ser9-GSK-3β and β-catenin in comparison to Mock and NC groups, while transfection of miR-26b inhibitors showed the opposite effect. In miR-26b mimic group, TNF-α, IL- 1β and IL-6 levels were lower than the Mock and NC groups, while in miR-26b inhibitor group, these cytokine levels were higher than the Mock and NC groups (P < 0.05). Transfection of miR-26b mimics significantly reduced the cell proliferation of RAFLS, compared to the Mock and NC groups, and miR-26b inhibitors increased the proliferative capacity of RAFLS compared to Mock and NC groups (P < 0.05). The miR-26b mimic group exhibited higher RAFLS apoptosis rate compared to Mock and NC group and miR-26b inhibitor group showed significantly lower RAFLS apoptosis rate compared to Mock and NC groups (P < 0.05).

Conclusions

MiR-26b regulates β-catenin and CyclinD1 levels by inhibiting GSK-3β expression, which in-turn alters the Wnt/GSK-3β/β-catenin pathway to lower RAFLS proliferation and elevate cell apoptosis and the secretion of TNF-α,IL-1β and IL-6 cytokines. Therefore, our results show that miR-26B plays a central role in inhibiting the inflammation associated with rheumatoid arthritis.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9063056861547150