Impacting tumor cell-fate by targeting the inhibitor of apoptosis protein survivin

Nucleolin aptamer conjugated MSNPs-PLR-PEG multifunctional nanoconstructs for targeted co-delivery of anticancer drug and siRNA to counter drug resistance in TNBC

The emergence of drug resistance in cancer cells is among the major challenges for treating cancer. In the last few years, the co-delivery of drug and siRNA has shown promising results against drug-resistant cancers. In the present study, we developed mesoporous silica-based multifunctional nanocarrier for co-delivery against drug-resistant triple-negative breast cancer (TNBC) cells. We synthesized the nanocarrier by modifying mesoporous silica nanoparticles with poly-L-arginine, polyethylene glycol and AS1411 aptamer to impart siRNA binding ability, biocompatibility, and cancer cell specificity, respectively. We optimized the loading of doxorubicin (DOX) within the developed nanocarrier to avoid interference with siRNA binding. We ascertained the target specificity by performing a receptor blockade assay during cellular uptake studies. The cytotoxic efficacy of DOX and siRNA co-delivered using the developed nanocarrier was assessed using DOX-resistant MDA-MB-231 TNBC cells. The nanocarrier exhibited >10-fold and 40-fold reduction in the IC₅₀ values of DOX due to co-delivery with BCl-xL and BCL-2 siRNA, respectively. The results were further validated using a 3-D in vitro cell culture system. This study demonstrates that the targeted co-delivery of drug and siRNA has a strong potential to overcome drug resistance in TNBC cells.

Monitoring the in vivo siRNA release from lipid nanoparticles based on the fluorescence resonance energy transfer principle

The siRNA-loaded lipid nanoparticles have attracted much attention due to its significant gene silencing effect and successful marketization. However, the in vivo distribution and release of siRNA still cannot be effectively monitored. In this study, based on the fluorescence resonance energy transfer (FRET) principle, a fluorescence dye Cy5-modified survivin siRNA was conjugated to nanogolds (Au-DR-siRNA), which were then wrapped with lipid nanoparticles (LNPs) for monitoring the release behaviour of siRNA in vivo. The results showed that once Au-DR-siRNA was released from the LNPs and cleaved by the Dicer enzyme to produce free siRNA in cells, the fluorescence of Cy5 would change from quenched state to activated state, showing the location and time of siRNA release. Besides, the LNPs showed a significant antitumor effect by silencing the survivin gene and a CT imaging function superior to iohexol by nanogolds. Therefore, this work provided not only an effective method for monitoring the pharmacokinetic behaviour of LNP-based siRNA, but also a siRNA delivery system for treating and diagnosing tumors.

Survivin in Breast Cancer: A Review

Breast cancer is the most frequently diagnosed cancer in women and ranks second among causes for cancer-related death in women. Gene technology has led to the recognition that breast cancer is a heterogeneous disease composed of different biological subtypes, and genetic profiling enables the response to chemotherapy to be predicted. This fact emphasizes the importance of selecting sensitive diagnostic and prognostic markers in the early disease stage and more efficient targeted treatments for this disease. One such prognostic marker appears to be survivin. Many studies have shown that survivin is strongly expressed in different types of cancers. Its overexpression has been demonstrated in breast cancer, and high activity of the survivin gene has been associated with a poor prognosis and worse survival rates.

Antigen-Specific TCR-T Cells for Acute Myeloid Leukemia: State of the Art and Challenges

The cytogenetic abnormalities and molecular mutations involved in acute myeloid leukemia (AML) lead to unique treatment challenges. Although adoptive T-cell therapies (ACT) such as chimeric antigen receptor (CAR) T-cell therapy have shown promising results in the treatment of leukemias, especially B-cell malignancies, the optimal target surface antigen has yet to be discovered for AML. Alternatively, T-cell receptor (TCR)-redirected T cells can target intracellular antigens presented by HLA molecules, allowing the exploration of a broader territory of new therapeutic targets. Immunotherapy using adoptive transfer of WT1 antigen-specific TCR-T cells, for example, has had positive clinical successes in patients with AML. Nevertheless, AML can escape from immune system elimination by producing immunosuppressive factors or releasing several cytokines. This review presents recent advances of antigen-specific TCR-T cells in treating AML and discusses their challenges and future directions in clinical applications.

Apoptosis Deregulation and the Development of Cancer Multi-Drug Resistance

Simple Summary

Despite recent therapeutic advances against cancer, many patients do not respond well or respond poorly, to treatment and develop resistance to more than one anti-cancer drug, a term called multi-drug resistance (MDR). One of the main factors that contribute to MDR is the deregulation of apoptosis or programmed cell death. Herein, we describe the major apoptotic pathways and discuss how pro-apoptotic and anti-apoptotic proteins are modified in cancer cells to convey drug resistance. We also focus on our current understanding related to the interactions between survival and cell death pathways, as well as on mechanisms underlying the balance shift towards cancer cell growth and drug resistance. Moreover, we highlight the role of the tumor microenvironment components in blocking apoptosis in MDR tumors, and we discuss the significance and potential exploitation of epigenetic modifications for cancer treatment. Finally, we summarize the current and future therapeutic approaches for overcoming MDR.

Abstract

The ability of tumor cells to evade apoptosis is established as one of the hallmarks of cancer. The deregulation of apoptotic pathways conveys a survival advantage enabling cancer cells to develop multi-drug resistance (MDR), a complex tumor phenotype referring to concurrent resistance toward agents with different function and/or structure. Proteins implicated in the intrinsic pathway of apoptosis, including the Bcl-2 superfamily and Inhibitors of Apoptosis (IAP) family members, as well as their regulator, tumor suppressor p53, have been implicated in the development of MDR in many cancer types. The PI₃K/AKT pathway is pivotal in promoting survival and proliferation and is often overactive in MDR tumors. In addition, the tumor microenvironment, particularly factors secreted by cancer-associated fibroblasts, can inhibit apoptosis in cancer cells and reduce the effectiveness of different anti-cancer drugs. In this review, we describe the main alterations that occur in apoptosis-and related pathways to promote MDR. We also summarize the main therapeutic approaches against resistant tumors, including agents targeting Bcl-2 family members, small molecule inhibitors against IAPs or AKT and agents of natural origin that may be used as monotherapy or in combination with conventional therapeutics. Finally, we highlight the potential of therapeutic exploitation of epigenetic modifications to reverse the MDR phenotype.

Lipoic Acid-Modified Oligoethyleneimine-Mediated miR-34a Delivery to Achieve the Anti-Tumor Efficacy

MiR-34a, an important tumor suppressor, has been demonstrated to possess great potential in tumor gene therapy. To achieve the upregulation of miR-34a expression level, an oligoethyleneimine (OEI) derivative was constructed and employed as the carrier through the modification with lipoic acid (LA), namely LA-OEI. In contrast to OEI, the derivative LA-OEI exhibited superior transfection efficiency measured by confocal laser scanning microscopy and flow cytometry, owing to rapid cargo release in the disulfide bond-based reduction sensitive pattern. The anti-proliferation and anti-migration effects were tested after the miR-34a transfection to evaluate the anti-tumor response, using human cervical carcinoma cell line HeLa as a model. The delivery of LA-OEI/miR-34a nanoparticles could achieve obvious anti-proliferative effect caused by the induction of cell apoptosis and cell cycle arrest at G1 phase. In addition, it could inhibit the migration of tumor cells via the downregulation of MMP-9 and Notch-1 level. Overall, the LA-OEI-mediated miR-34a delivery was potential to be used as an effective way in the tumor gene therapy.

Survivin as a biological biomarker for diagnosis and therapy

Introduction: Survivin (SVN) is a member of the inhibitor of apoptosis (IAP) protein family that promotes cellular proliferation and inhibits apoptosis. Overexpression of SVN is associated with autoimmune disease, hyperplasia, and tumors and can be used as a biomarker in these diseases. SVN is widely recognized as a tumor-associated antigen (TAA) and has become an important target for cancer diagnosis and treatment.Areas covered: We reviewed SVN research progress from the PubMed and clinical trials focused on SVN from https://clinicaltrials.gov since 2000 and anticipate future developments in the field. The trials reviewed cover various modalities including diagnostics for early detection and disease progression, small molecule inhibitors of the SVN pathway and immunotherapy targeting SVN epitopes.Expert opinion: The most promising developments involve anti-SVN immunotherapy, with several therapeutic SVN vaccines under evaluation in phase I/II trials. SVN is an important new immune-oncology target that expands the repertoire of individualized combination treatments for cancer.

Identification of prognostic markers for hepatocellular carcinoma based on the epithelial-mesenchymal transition-related gene BIRC5

BACKGROUND

The baculoviral IAP repeat containing 5 (BIRC5) related to epithelial-mesenchymal transition (EMT) plays a crucial role in the pathogenesis of hepatocellular carcinoma (HCC). However, it remains unclear whether BIRC5-related genes can be used as prognostic markers of HCC.

METHODS

Kaplan-Meier (K-M) survival curve was used to assess the Overall Survival (OS) of high- and low-expression group divided by the median of BIRC5 expression. The differentially expressed genes (DEGs) between the two groups were screened using the limma package, and performed the functional enrichment analysis by the clusterProfiler package. WGCNA was used to analyze the relationship of the module and the clinical traits. The risk signature was constructed by univariate and multivariate Cox regression analyses and the enrichment analysis of genes in the risk signature was performed by the Intelligent pathway analysis (IPA). The immunophenoscore (IPS) and the tumor immune dysfunction and exclusion (TIDE) were used to estimate the clinical significance of the risk groups.

RESULTS

BIRC5 was high-expressed in HCC samples and associated with a poor prognosis (p-value < 0.0001). WGCNA screened 180 module genes which were overlapped with the 241 DEGs, ultimately getting 33 candidate genes. After the Cox regression analyses, CENPA, CDCA8, EZH2, KIF20A, KPNA2, CCNB1, KIF18B and MCM4 were preserved and used to construct risk signature, followed by calculating the risk score. The patients in high-risk groups stratified by median of the risk score were associated with a poor prognosis. The risk score had high accuracy [the area under the curve (AUC) > 0.72] and was closely associated with clinicopathological characteristics of HCC patients. IPA suggested that the 8 genes were enriched in Cancer and Immunological disease related pathways. IPS and TIDE score indicated that the genes in low-risk group could cause an immune response, and patients in the low-risk group may be more sensitive to the immune checkpoint blockade (ICB) therapy.

CONCLUSION

The risk score constructed by the 8 genes could not only predict the clinical outcome but also distinguish the cohort of ICB therapy in HCC, which exerted a vital value in treatment and prognosis of HCC.

Emerging Importance of Survivin in Stem Cells and Cancer: the Development of New Cancer Therapeutics

Survivin is one of the rare proteins that is differentially expressed in normal and cancer cells and is directly or indirectly involved in numerous pathways required for tumor maintenance. It is expressed in almost all cancers and its expression has been detected at early stages of cancer. These traits make survivin an exceptionally attractive target for cancer therapeutics. Even with these promising features to be an oncotherapeutic target, there has been limited success in the clinical trials targeting survivin. Only recently it has emerged that survivin was not being specifically targeted which could have resulted in the negative clinical outcome. Also, focus of research has now shifted from survivin expression in the overall heterogeneous tumor cell populations to survivin expression in cancer stem cells as these cells have proved to be the major drivers of tumors. Therefore, in this review we have analyzed the expression of survivin in normal and cancer cells with a particular focus on its expression in cancer stem cell compartment. We have discussed the major signaling pathways involved in regulation of survivin. We have explored the current development status of various types of interventions for inhibition of survivin. Furthermore, we have discussed the challenges involving the development of potent and specific survivin inhibitors for cancer therapeutics. Finally we have given insights for some of the promising future anticancer treatments.

Development of New Targeted Inulin Complex Nanoaggregates for siRNA Delivery in Antitumor Therapy

Here, a novel strategy of formulating efficient polymeric carriers based on the already described INU-IMI-DETA for gene material whose structural, functional, and biological properties can be modulated and improved was successfully investigated. In particular, two novel derivatives of INU-IMI-DETA graft copolymer were synthesized by chemical functionalisation with epidermal growth factor (EGF) or polyethylenglycol (PEG), named INU-IMI-DETA-EGF and INU-IMI-DETA-PEG, respectively, in order to improve the performance of already described "inulin complex nanoaggregates" (ICONs). The latter were thus prepared by appropriately mixing the two copolymers, by varying each component from 0 to 100 wt% on the total mixture, named EP-ICONs. It was seen that the ability of the INU-IMI-DETA-EGF/INU-IMI-DETA-PEG polymeric mixture to complex siGL3 increases with the increase in the EGF-based component in the EP-ICONs and, for each sample, with the increase in the copolymer:siRNA weight ratio (R). On the other hand, the susceptibility of loaded siRNA towards RNase decreases with the increase in the pegylated component in the polymeric mixture. At all R values, the average size and the zeta potential values are suitable for escaping from the RES system and suitable for prolonged intravenous circulation. By means of biological characterisation, it was shown that MCF-7 cells are able to internalize mainly the siRNA-loaded into EGF-decorated complexes, with a significant difference from ICONs, confirming its targeting function. The targeting effect of EGF on EP-ICONs was further demonstrated by a competitive cell uptake study, i.e., after cell pre-treatment with EGF. Finally, it was shown that the complexes containing both EGF and PEG are capable of promoting the internalisation and therefore the transfection of siSUR, a siRNA acting against surviving mRNA, and to increase the sensitivity to an anticancer agent, such as doxorubicin.

Improved safety of induced pluripotent stem cell-derived antigen-presenting cell-based cancer immunotherapy

The tumorigenicity and toxicity of induced pluripotent stem cells (iPSCs) and their derivatives are major safety concerns in their clinical application. Recently, we developed granulocyte-macrophage colony-stimulating factor (GM-CSF)-producing proliferating myeloid cells (GM-pMCs) from mouse iPSCs as a source of unlimited antigen-presenting cells for use in cancer immunotherapy. As GM-pMCs are generated by introducing c-Myc and Csf2 into iPSC-derived MCs and are dependent on self-produced GM-CSF for proliferation, methods to control their proliferation after administration should be introduced to improve safety. In this study, we compared the efficacy of two promising suicide gene systems, herpes simplex virus-thymidine kinase (HSV-TK)/ganciclovir (GCV) and inducible caspase-9 (iCasp9)/AP1903, for safeguarding GM-pMCs in cancer immunotherapy. The expression of HSV-TK or iCasp9 did not impair the fundamental properties of GM-pMCs. Both of these suicide gene-expressing cells selectively underwent apoptosis after treatment with the corresponding apoptosis-inducing drug, and they were promptly eliminated in vivo. iCasp9/AP1903 induced apoptosis more efficiently than HSV-TK/GCV. Furthermore, high concentrations of GCV were toxic to cells not expressing HSV-TK, whereas AP1903 was bioinert. These results suggest that iCasp9/AP1903 is superior to HSV-TK/GCV in terms of both safety and efficacy when controlling the fate of GM-pMCs after priming antitumor immunity.

Foeniculum vulgare seed extract exerts anti-cancer effects on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. The prognosis of HCC is very poor due to the absence of symptoms and a lack of effective treatments. Studies have shown that various Foeniculum vulgare (fennel) extracts exhibit anti-cancer effects on malignant tumors such as skin cancer and prostate cancer. However, the anti-tumor activity of Foeniculum vulgare and its underlying molecular mechanisms towards HCC are unknown. Here, we provide fundamental evidence to show that the 75% ethanol extract of Foeniculum vulgare seeds (FVE) reduced cell viability, induced apoptosis, and effectively inhibited cell migration in HCC cells in vitro. HCC xenograft studies in nude mice showed that FVE significantly inhibited HCC growth in vivo. Mechanistic analyses showed that FVE reduced survivin protein levels and triggered mitochondrial toxicity, subsequently inducing caspase-3 activation and apoptosis. Survivin inhibition effectively sensitized HCC cells to FVE-induced apoptosis. Moreover, FVE did not induce a decrease in survivin or apoptotic toxicity in normal liver cells. Collectively, in vivo and in vitro results suggest that FVE exerts inhibitory effects in HCC by targeting the oncoprotein survivin, suggesting FVE may be a potential anti-cancer agent that may benefit patients with HCC.

Morusin inhibits the growth of human colorectal cancer HCT116‑derived sphere‑forming cells via the inactivation of Akt pathway

The existence of colorectal cancer stem-like cells (CSC) is responsible for the failure of current treatments against colorectal cancer. Therefore, novel therapies need be developed to target CSCs. Some natural agents, including morusin have been proposed as possible candidates for this purpose. Morusin has been shown to exert antitumor effects. In the present study, it is demonstrated that morusin exerts antitumor effects on colorectal CSCs (CCSCs). The viability of human CCSCs was enhanced when the CCSCs formed spheroids in a serum-free and non-adhesive floating culture system. HCT116 sphere cells exhibited an increased proliferative capacity and a higher expression of stemness markers [octamer-binding transcription factor 4 (Oct4), Sox2 and Nanog]. Morusin inhibited the development of cancer spheroids and suppressed the growth of sphere cells via the induction of cell cycle arrest. Similarly, morusin decreased the expression levels of the stemness markers, Nanog and Oct4. The data partially revealed the molecular mechanisms involved: β-catenin signaling maintains the growth of CSCs and directly modulates the expression of Nanog and Oct4. Morusin suppressed the activity of β-catenin signaling via the inactivation of Akt; the executive β-catenin/TCF4 complex and the downstream targets, c-Myc, survivin and cyclin D1, were also downregulated. Moreover, the morusin-induced inactivation of Akt also increased the expression of p21Cip1/WAF1 and p27Kip, which can block the cell cycle by interacting with cyclin-dependent kinase (CDK) complexes. On the whole, the present study demonstrates that morusin inhibited the growth of colorectal cancer sphere cells, which were enriched with CCSCs via the inactivation of the Akt pathway.

Effect of Sepatronium Bromide (YM-155) on DNA Double-Strand Breaks Repair in Cancer Cells

Survivin, as an antiapoptotic protein often overexpressed in cancer cells, is a logical target for potential cancer treatment. By overexpressing survivin, cancer cells can avoid apoptotic cell death and often become resistant to treatments, representing a significant obstacle in modern oncology. A survivin suppressor, an imidazolium-based compound known as YM-155, is nowadays studied as an attractive anticancer agent. Although survivin suppression by YM-155 is evident, researchers started to report that YM-155 is also an inducer of DNA damage introducing yet another anticancer mechanism of this drug. Moreover, the concentrations of YM-155 for DNA damage induction seems to be far lower than those needed for survivin inhibition. Understanding the molecular mechanism of action of YM-155 is of vital importance for modern personalized medicine involving the selection of responsive patients and possible treatment combinations. This review focuses mainly on the documented effects of YM-155 on DNA damage signaling pathways. It summarizes up to date literature, and it outlines the molecular mechanism of YM-155 action in the context of the DNA damage field.

Single-cell transcriptomic analysis in a mouse model deciphers cell transition states in the multistep development of esophageal cancer

Esophageal squamous cell carcinoma (ESCC) is prevalent in some geographical regions of the world. ESCC development presents a multistep pathogenic process from inflammation to invasive cancer; however, what is critical in these processes and how they evolve is largely unknown, obstructing early diagnosis and effective treatment. Here, we create a mouse model mimicking human ESCC development and construct a single-cell ESCC developmental atlas. We identify a set of key transitional signatures associated with oncogenic evolution of epithelial cells and depict the landmark dynamic tumorigenic trajectories. An early downregulation of CD8⁺ response against the initial tissue damage accompanied by the transition of immune response from type 1 to type 3 results in accumulation and activation of macrophages and neutrophils, which may create a chronic inflammatory environment that promotes carcinogen-transformed epithelial cell survival and proliferation. These findings shed light on how ESCC is initiated and developed.

NetConfer: a web application for comparative analysis of multiple biological networks

Background

Most biological experiments are inherently designed to compare changes or transitions of state between conditions of interest. The advancements in data intensive research have in particular elevated the need for resources and tools enabling comparative analysis of biological data. The complexity of biological systems and the interactions of their various components, such as genes, proteins, taxa, and metabolites, have been inferred, represented, and visualized via graph theory-based networks. Comparisons of multiple networks can help in identifying variations across different biological systems, thereby providing additional insights. However, while a number of online and stand-alone tools exist for generating, analyzing, and visualizing individual biological networks, the utility to batch process and comprehensively compare multiple networks is limited.

Results

Here, we present a graphical user interface (GUI)-based web application which implements multiple network comparison methodologies and presents them in the form of organized analysis workflows. Dedicated comparative visualization modules are provided to the end-users for obtaining easy to comprehend, insightful, and meaningful comparisons of various biological networks. We demonstrate the utility and power of our tool using publicly available microbial and gene expression data.

Conclusion

NetConfer tool is developed keeping in mind the requirements of researchers working in the field of biological data analysis with limited programming expertise. It is also expected to be useful for advanced users from biological as well as other domains (working with association networks), benefiting from provided ready-made workflows, as they allow to focus directly on the results without worrying about the implementation. While the web version allows using this application without installation and dependency requirements, a stand-alone version has also been supplemented to accommodate the offline requirement of processing large networks.

Combination of the natural compound Periplocin and TRAIL induce esophageal squamous cell carcinoma apoptosis in vitro and in vivo: Implication in anticancer therapy

BACKGROUND

Esophageal cancer is one of the most common malignant tumors in the world. With currently available therapies, only 20% ~ 30% patients can survive this disease for more than 5 years. TRAIL, a natural ligand for death receptors that can induce the apoptosis of cancer cells, has been explored as a therapeutic agent for cancers, but it has been reported that many cancer cells are resistant to TRAIL, limiting the potential clinical use of TRAIL as a cancer therapy. Meanwhile, Periplocin (CPP), a natural compound from dry root of Periploca sepium Bge, has been studied for its anti-cancer activity in a variety of cancers. It is not clear whether CPP and TRAIL can have activity on esophageal squamous cell carcinoma (ESCC) cells, or whether the combination of these two agents can have synergistic activity.

METHODS

We used MTS assay, flow cytometry and TUNEL assay to detect the effects of CPP alone or in combination with TRAIL on ESCC cells. The mechanism of CPP enhances the activity of TRAIL was analyzed by western blot, dual luciferase reporter gene assay and chromatin immunoprecipitation (ChIP) assay. The anti-tumor effects and the potential toxic side effects of CPP alone or in combination with TRAIL were also evaluated in vivo.

RESULTS

In our studies, we found that CPP alone or in combination with TRAIL could inhibit the proliferation of ESCC cells and induce apoptosis, and we certificated that combination of two agents exert synergized functions. For the first time, we identified FoxP3 as a key transcriptional repressor for both DR4 and DR5. By down-regulating FoxP3, CPP increases the expression of DR4/DR5 and renders ESCC cells much more sensitive to TRAIL. We also showed that CPP reduced the expression of Survivin by inhibiting the activity of Wnt/β-catenin pathway. All these contributed to synergistic activity of CPP and TRAIL on ESCC cells in vitro and in vivo.

CONCLUSION

Our data suggest that CPP and TRAIL could be further explored as potential therapeutic approach for esophageal cancer.

Functional Compartmentalization of HSP60-Survivin Interaction between Mitochondria and Cytosol in Cancer Cells

Heat shock protein 60 (HSP60) and survivin reside in both the cytosolic and mitochondrial compartments under physiological conditions. They can form HSP60-survivin complexes through protein–protein interactions. Their expression levels in cancer tissues are positively correlated and higher expression of either protein is associated with poor clinical prognosis. The subcellular location of HSP60-survivin complex in either the cytosol or mitochondria is cell type-dependent, while the biological significance of HSP60-survivin interaction remains elusive. Current knowledge indicates that the function of HSP60 partly rests on where HSP60-survivin interaction takes place. HSP60 has a pro-survival function when binding to survivin in the mitochondria through interacting with other factors such as CCAR2 and p53. In response to cell death signals, mitochondrial survivin functions through preventing procaspase activation. Degradation of cytosolic survivin leads to the loss of mitochondrial membrane potential and aberrant mitosis processes. On the other hand, HSP60 release from mitochondria to cytosol upon death stimuli might exert a pro-death function, either through stabilizing Bax, enhancing procaspase-3 activation, or increasing protein ubiquitination. Combining the knowledge of mitochondrial HSP60-survivin complex function, cytosolic survivin degradation effect, and pro-death function upon mitochondria release of HSP60, a hypothetical scenario for HSP60-survivin shuttling upon death stimuli is proposed.

Small-Molecule Intervention At The Dimerization Interface Of Survivin By Novel Rigidized Scaffolds

Introduction

Survivin is a nodal protein involved in several cellular pathways. It is a member of the IAP family and an integral component of the chromosomal passenger complex, where it binds to borealin and INCENP through its dimerization interface. By targeting survivin with a small molecule at its dimerization interface, inhibition of the proliferation of cancer cells has been suggested. With Abbott 8, a small-molecule dimerization inhibitor has been recently reported. The structure–activity relationship of this series of inhibitors implied that the middle pyridin-2(1H)-one ring did not tolerate modifications of any kind.

Methods

Based on the synthetic strategy of Abbott 8 using multicomponent reactions, we synthesized a series of small molecules bearing a novel rigidized core scaffold. This rigidization strategy was accomplished by integrating the pyridin-2(1H)-one and its 6-phenyl substituent into a tricyclic structure, linking position 5 of pyridin-2(1H)-one to the phenyl substituent by rings of different sizes. The new scaffolds were designed based on in silico molecular dynamics of survivin.

Results

Binding of these rigidized scaffolds to the recombinant L54M mutant of survivin was evaluated, revealing affinities in the low micromolar range.

Conclusion

This easily accessible, new class of survivin-dimerization modulators is an interesting starting point for further lead optimization.

d-a-Tocopheryl Polyethylene Glycol 1000 Succinate and a small-molecule Survivin suppressant synergistically induce apoptosis in SKBR3 breast cancer cells

Breast cancer is the second in mortality rate malignancy among women. Despite the many advances in breast cancer treatment, there is still a need to improve drug efficacy and reduce non-specific effects. D-alpha-tocopheryl polyethylene glycol succinate (TPGS) is frequently used in the development of drug delivery systems to improve the pharmacokinetics of anti-cancer drugs and reduce multi-drug resistance. We have previously shown that TPGS not only acts as a carrier molecule but also exerts anti-cancer effects. As part of this study, we investigated the effect of TPGS with YM155, a small molecule suppressant of Survivin, in various breast cancer cell lines representing different subtypes of the disease. We aimed to evaluate the presumed synergistic effect of the TPGS-YM155 combination and reveal its mechanism of action. Our results show that the TPGS-YM155 combination acts synergistically to reduce specifically the viability of SKBR3 cells. The combination of these agents reduced activation of the AKT pathway, decreased Survivin and Bcl-2 levels, and induced caspase-dependent and independent apoptosis via the mitochondrial pathway. Importantly, the TPGS-YM155 combination did not significantly affect the viability of MCF-10A normal immortalized cells. In conclusion, the combination of YM155 and TPGS could be a promising approach against SKBR3-type breast cancer.

Growth arrest and apoptosis induced by kinesin Eg5 inhibitor K858 and by its 1,3,4-thiadiazoline analogue in tumor cells

Tumors are complex and heterogeneous but, despite this, they share the ability to proliferate continuously, irrespective of the presence of growth signals, leading to a higher fraction of actively growing and dividing cells compared with normal tissues. For this reason, the cytotoxic antimitotic treatments remain an important clinical tool for tumors. Among these drugs, antitubulin compounds constitute one of the most effective anticancer chemotherapies; however, they cause dose-limiting side effects. Therefore, it is still necessary to develop compounds with new targets and new mechanisms of action to reduce side effects or chemoresistance. Mitosis-specific kinesin Eg5 can represent an attractive target for discovering such new anticancer agents because its role is fundamental in mitotic progression. Therefore, we analyzed the effects induced by an inhibitor of kinesin Eg5, K858, and by its 1,3,4-thiadiazoline analogue on human melanoma and prostate cancer cell lines. We found that both compounds have an antiproliferative effect, induce apoptosis, and can determine a downmodulation of survivin.

Expression Profile of Survivin and p16 in Laryngeal Squamous Cell Carcinoma: Contribution of Tunisian Patients

The objective of this study was to evaluate the expression of survivin and p16 in laryngeal squamous cell carcinoma (LSCC) in order to analyze their pathogenesis and prognostic significance in Tunisian patients. A total of 70 patients with LSCC collected at the Salah Azaiez Cancer Institute of Tunis were retrospectively evaluated. Expression of survivin and p16 was examined using immunohistochemistry, and the correlations with clinicopathological parameters, overall survival (OS), and disease-free survival (DFS) were statistically evaluated. The positive expression of survivin and p16 were found in 58.6% and 51.43% of LSCC cases, respectively. The p16 expression was not associated with either clinical parameters or patient survival, whereas there was a strong correlation of survivin expression and lymph node metastases (P = .002), alcohol consumption (P = .024), and therapeutic protocol (with or without chemotherapy; P = .001). Kaplan-Meier survival curves showed that patients with LSCC having positive survivin expression have shorter OS (P = .026) and shorter DFS (P = .01) than those with negative expression. Positive survivin expression was also correlated with high recurrence rate (P = .014). Therefore, survivin is a poor prognostic marker for LSCC but the therapeutic protocol remains, in multivariate study, the most decisive for the OS and DFS of our patients with P < .01. Our data indicated that, in Tunisian laryngeal squamous cell carcinoma, survivin expression is associated with unfavorable outcomes and represents a predictor marker of recurrence and chemoresistance. However, p16 expression has no prognosis value.

Inhibition of anaplastic lymphoma kinase promotes apoptosis and suppresses proliferation in human hepatocellular carcinoma

Our study was to examine the roles of crizotinib and ceritinib in hepatocellular carcinoma (HCC) cells and explore the possible mechanisms. MTT assay was employed to examine the proliferation of five HCC cell lines treated with various concentrations of crizotinib or ceritinib. HepG2 and HCCLM3 cells were incubated with 2 nmol/l ceritinib for 1 week, followed by crystal violet staining and cell counting. Protein amounts of t-ALK, p-ALK, t-AKT, p-AKT, t-ERK, p-ERK, Mcl-1, survivin, and XIAP in HepG2 cells under different culture conditions were evaluated by western blot. HepG2 and HCCLM3 cells were treated with vehicle or ceritinib and measured by flow cytometry apoptosis analysis with Annexin-V/propidium iodide staining. MTT assay showed that both crizotinib and ceritinib suppressed the proliferation of various human HCC cells. Crystal violet staining analysis also indicated that ceritinib effectively inhibited human HCC cell proliferation. Western blot analysis indicated that both crizotinib and ceritinib inhibited ALK, AKT, and ERK phosphorylations. In addition, ceritinib reduced antiapoptotic gene expressions in HepG2 cells. Flow cytometry analysis indicated that ceritinib induced HepG2 and HCCLM3 cells apoptosis. ALK inhibitor exhibited antitumor effects by inhibiting ALK activation, repressing AKT and ERK pathways, and suppressing antiapoptotic gene expressions, which subsequently promoted apoptosis and suppressed HCC cell proliferations.

Exosomal survivin facilitates vesicle internalization

Survivin, a member of the inhibitor of apoptosis (IAP) protein family plays a significant role in cell fate and function. It is significantly overexpressed in tumor cells and has been identified in most cancer cell types. A novel extracellular population has recently been identified and its function is still unknown. Emerging evidence continues to shed light on the important role the tumor microenvironment (TME) has on tumor survival and progression. This new population of survivin has been seen to enhance the tumor phenotype when internalized by recipient cells. In this paper, we sought to better understand the mechanism by which survivin is taken up by cancer cells and the possible role it plays in this phenomenon. We isolated the exosomal carriers of extracellular survivin and using a lipophilic stain, PKH67, we tracked their uptake with immunofluorescence and flow cytometry. We found that by blocking exosomal survivin, exosome internalization is reduced, signifying a novel function for this protein. We also discovered that the common membrane receptors, transferrin receptor, endothelin B receptor, insulin receptor alpha, and membrane glucocorticoid receptor all facilitate exosomal internalization. This understanding further clarifies the protein-protein interactions in the TME that may influence tumor progression and identifies additional potential chemotherapeutic targets.

Survivin expression modulates the sensitivity of A549 lung cancer cells resistance to vincristine

Lung cancer is the leading cause of cancer-associated mortalities worldwide. Chemotherapeutic drug vincristine is widely used to treat lung cancer; however, the acquisition of drug resistance is the major limitation of chemotherapy, and it is thus important to determine the mechanism underlying vincristine resistance in lung cancer. Survivin has been reported to be associated with the development of drug resistance and be involved in the progression of non-small cell lung cancer. In the present study, a vincristine-resistant lung cancer cell line, A549/VCR, was used to investigate the possible involvement of survivin in the acquisition of vincristine resistance. Western blot analysis demonstrated that survivin protein expression level was markedly higher in A549/VCR cells compared with in control A549 cells, whereas p53 expression level was lower in A549/VCR cells compared with in A549 cells. Thus, wild-type p53 was overexpressed in A549/VCR cells and it reversed vincristine resistance of A549/VCR cells via the inhibition of survivin expression. Furthermore, survivin was knocked down by small interfering RNA technology and the effects on viability and apoptosis of resistant cells were investigated. MTT, Annexin V-fluorescein isothiocyanate/propidium iodide and caspase-3 activity assays indicated that survivin silencing significantly inhibited cell viability and enhanced apoptosis induced by vincristine treatment in A549/VCR cells compared with non-silenced A549/VCR cells. These results suggested that survivin expression regulated by p53 may serve an important role in drug resistance in A549/VCR cells and may be a potential target for enhancing vincristine sensitivity in A549 lung cancer cells. Additionally, the present study revealed that A549/VCR cells exhibited cross resistance to methotrexate (MTX) and survivin silencing re-sensitized A549/VCR cells to MTX, indicating the crucial role of survivin in regulating A549 cells sensitivity to anticancer drugs. The results of the present study are significant for determining the underlying mechanism of vincristine resistance in lung cancer.

Microarray gene expression profiling in colorectal (HCT116) and hepatocellular (HepG2) carcinoma cell lines treated with Melicope ptelefolia leaf extract reveals transcriptome profiles exhibiting anticancer activity

Background

We have previously reported anticancer activities of Melicope ptelefolia (MP) leaf extracts on four different cancer cell lines. However, the underlying mechanisms of actions have yet to be deciphered. In the present study, the anticancer activity of MP hexane extract (MP-HX) on colorectal (HCT116) and hepatocellular carcinoma (HepG2) cell lines was characterized through microarray gene expression profiling.

Methods

HCT116 and HepG2 cells were treated with MP-HX for 24 hr. Total RNA was extracted from the cells and used for transcriptome profiling using Applied Biosystem GeneChip™ Human Gene 2.0 ST Array. Gene expression data was analysed using an Applied Biosystems Expression Console and Transcriptome Analysis Console software. Pathway enrichment analyses was performed using Ingenuity Pathway Analysis (IPA) software. The microarray data was validated by profiling the expression of 17 genes through quantitative reverse transcription PCR (RT-qPCR).

Results

MP-HX induced differential expression of 1,290 and 1,325 genes in HCT116 and HepG2 cells, respectively (microarray data fold change, MA_FC ≥ ±2.0). The direction of gene expression change for the 17 genes assayed through RT-qPCR agree with the microarray data. In both cell lines, MP-HX modulated the expression of many genes in directions that support antiproliferative activity. IPA software analyses revealed MP-HX modulated canonical pathways, networks and biological processes that are associated with cell cycle, DNA replication, cellular growth and cell proliferation. In both cell lines, upregulation of genes which promote apoptosis, cell cycle arrest and growth inhibition were observed, while genes that are typically overexpressed in diverse human cancers or those that promoted cell cycle progression, DNA replication and cellular proliferation were downregulated. Some of the genes upregulated by MP-HX include pro-apoptotic genes (DDIT3, BBC3, JUN), cell cycle arresting (CDKN1A, CDKN2B), growth arrest/repair (TP53, GADD45A) and metastasis suppression (NDRG1). MP-HX downregulated the expression of genes that could promote anti-apoptotic effect, cell cycle progression, tumor development and progression, which include BIRC5, CCNA2, CCNB1, CCNB2, CCNE2, CDK1/2/6, GINS2, HELLS, MCM2/10 PLK1, RRM2 and SKP2. It is interesting to note that all six top-ranked genes proposed to be cancer-associated (PLK1, MCM2, MCM3, MCM7, MCM10 and SKP2) were downregulated by MP-HX in both cell lines.

Discussion

The present study showed that the anticancer activities of MP-HX are exerted through its actions on genes regulating apoptosis, cell proliferation, DNA replication and cell cycle progression. These findings further project the potential use of MP as a nutraceutical agent for cancer therapeutics.

Sestrin 2 suppresses cells proliferation through AMPK/mTORC1 pathway activation in colorectal cancer

Sestrin 2 is a conserved antioxidant protein that reduces reactive oxygen species (ROS) and inhibits mammalian target of rapamycin complex 1 (mTORC1). We previously showed that sestrin 2 is abnormally decreased in colorectal cancer (CRC). To elucidate the molecular mechanism behind the potential contribution of sestrin 2 to CRC, we used a lentiviral expression vector system to determine the effects of sestrin 2 overexpression on human CRC cells. We found that sestrin 2 overexpression decreased ROS production, inhibited cell growth, and stimulated apoptosis in two CRC cell lines. In parallel, expression of the proliferation marker PCNA was decreased, proapoptotic caspase 3, 7, and 9 levels were increased, and expression of the anti-apoptotic protein survivin was reduced. Sestrin 2 overexpression also activated the adenosine monophosphate-activated protein kinase (AMPK) pathway, and suppressed mTORC1 signaling. Treating CRC cells with compound C, an AMPK inhibitor, reversed or attenuated changes in proliferation, apoptosis, and signaling proteins of the AMPK/mTORC1 axis. In a xenograft mouse model, CRC growth was attenuated by sestrin 2 overexpression. These results suggest that sestrin 2 suppresses CRC cell growth through activation of the AMPK/mTORC1 pathway and induction of apoptosis, and could be a novel pharmacological target for the treatment of CRC.

Survivin-Based Treatment Strategies for Squamous Cell Carcinoma

Survivin, an anti-apoptotic molecule abundantly expressed in most human neoplasms, has been reported to contribute to cancer initiation and drug resistance in a wide variety of human tumors. Efficient downregulation of survivin can sensitize tumor cells to various therapeutic interventions, generating considerable efforts in its validation as a new target in cancer therapy. This review thoroughly analyzes up-to-date information on the potential of survivin as a therapeutic target for new anticancer treatments. The literature dealing with the therapeutic targeting of survivin will be reviewed, discussing specifically squamous cell carcinomas (SCCs), and with emphasis on the last clinical trials. This review gives insight into the recent developments undertaken in validating various treatment strategies that target survivin in SCCs and analyze the translational possibility, identifying those strategies that seem to be the closest to being incorporated into clinical practice. The most recent developments, such as dominant-negative survivin mutants, RNA interference, anti-sense oligonucleotides, small-molecule inhibitors, and peptide-based immunotherapy, seem to be helpful for effectively downregulating survivin expression and reducing tumor growth potential, increasing the apoptotic rate, and sensitizing tumor cells to chemo- and radiotherapy. However, selective and efficient targeting of survivin in clinical trials still poses a major challenge.

[Sericin regulates proliferation of human gastric cancer MKN45 cells through autophagic pathway]

OBJECTIVE

To investigate the effect of sericin on the proliferation of human gastric cancer MKN45 cells and explore the underlying molecular mechanism.

METHODS

MKN45 cells were transfected by LC3 double fluorescent autophagic virus, and the positive cells screened by puromycin were divided into blank group, sericin group and sericin∓3-MA group. After incubation with sericin for 48 h, the cells were examined for proliferation, apoptosis and cell cycle using CCK-8 assay and flow cytometry. Cell autophagy was detected by transmission electron microscopy (TEM) and fluorescent inverted microscope, and the autophagy-related markers including LC3, p62 and Beclin proteins were detected with Western blotting. Nude mice bearing gastric cancer xenograft were treated with normal saline or sericin injections (n=5) and the changes in the tumor volume and weight were measured.

RESULTS

Compared with the blank group, MKN45 cells with sericin treatment showed significantly inhibited proliferation both in vitro and in nude mice. Autophagosomes were observed in sericin-treated cells under TEM and fluorescent inverted microscope. Sericin treatment of the cells significantly increased the cell apoptosis (P<0.01), caused obvious cell cycle arrest in G₂/M phase (P<0.01), up-regulated the expressions of both LC3-2 and Beclin, and down-regulated the expression of p62. The autophagy inhibitor 3-MA obviously antagonized the effects of sericin on cell apoptosis, cell cycle and autophagic protein expressions.

CONCLUSION

Sericin can inhibit the proliferation of human gastric cancer MKN45 cells by regulating cell autophagy to serve as potential anti-tumor agent.

[Sericin regulates proliferation of human gastric cancer MKN45 cells through autophagic pathway]

OBJECTIVE

To investigate the effect of sericin on the proliferation of human gastric cancer MKN45 cells and explore the underlying molecular mechanism.

METHODS

MKN45 cells were transfected by LC3 double fluorescent autophagic virus, and the positive cells screened by puromycin were divided into blank group, sericin group and sericin∓3-MA group. After incubation with sericin for 48 h, the cells were examined for proliferation, apoptosis and cell cycle using CCK-8 assay and flow cytometry. Cell autophagy was detected by transmission electron microscopy (TEM) and fluorescent inverted microscope, and the autophagy-related markers including LC3, p62 and Beclin proteins were detected with Western blotting. Nude mice bearing gastric cancer xenograft were treated with normal saline or sericin injections (n=5) and the changes in the tumor volume and weight were measured.

RESULTS

Compared with the blank group, MKN45 cells with sericin treatment showed significantly inhibited proliferation both in vitro and in nude mice. Autophagosomes were observed in sericin-treated cells under TEM and fluorescent inverted microscope. Sericin treatment of the cells significantly increased the cell apoptosis (P<0.01), caused obvious cell cycle arrest in G2/M phase (P<0.01), up-regulated the expressions of both LC3-2 and Beclin, and down-regulated the expression of p62. The autophagy inhibitor 3-MA obviously antagonized the effects of sericin on cell apoptosis, cell cycle and autophagic protein expressions.

CONCLUSION

Sericin can inhibit the proliferation of human gastric cancer MKN45 cells by regulating cell autophagy to serve as potential anti-tumor agent.

Survivin-targeting miR-542-3p overcomes HER3 signaling-induced chemoresistance and enhances the antitumor activity of paclitaxel against HER2-overexpressing breast cancer

Elevated expression of HER3, which interacts with HER2 in breast cancer cells, confers chemoresistance via phosphoinositide 3-kinase (PI-3K)/Akt-dependent upregulation of Survivin. However, the underlying mechanism is not clear. Ectopic expression or specific knockdown of HER3 in HER2-overexpressing breast cancer cells did not alter Survivin mRNA levels and Survivin protein stability, supporting the notion that HER3 signaling may regulate specific miRNAs that target Survivin to alter its protein translation. Here we showed that overexpression and specific knockdown of HER3 reduced and enhanced expression of two Survivin-targeting miRNAs, miR-203 and miR-542-3p, in breast cancer cells, respectively. While the specific inhibitor of either miR-203 or miR-542-3p attenuated an anti-HER3 antibody-induced downregulation of Survivin, inhibition of miR-542-3p exhibited a better efficacy than miR-203 inhibition did. Consistently, miR-542-3p mimic was much more effective than miR-203 mimic not only in inhibition of Survivin, but also in enhancement of paclitaxel-induced apoptosis in HER2-overexpressing breast cancer cells. Moreover, the combination of miR-542-3p mimic and paclitaxel, as compared with either agent alone, significantly inhibited in vivo tumor growth of HER2-overexpressing breast cancer cells. Collectively, our data indicated that the HER3/PI-3K/Akt signaling upregulates Survivin via suppression of miR-203 and miR-542-3p. Because miR-542-3p has three binding sites on the 3'-UTR of Survivin mRNA, its mimic was able to effectively downregulate Survivin in vitro and in vivo. Thus, miR-542-3p-replacement therapy is an excellent approach to overcome HER3-mediated paclitaxel resistance and significantly enhances the antitumor activity of paclitaxel against HER2-overexpressing breast cancer.

G2/M inhibitors as pharmacotherapeutic opportunities for glioblastoma: the old, the new, and the future

Glioblastoma (GBM) is one of the deadliest tumors and has a median survival of 3 months if left untreated. Despite advances in rationally targeted pharmacological approaches, the clinical care of GBM remains palliative in intent. Since the majority of altered signaling cascades involved in cancer establishment and progression eventually affect cell cycle progression, an alternative approach for cancer therapy is to develop innovative compounds that block the activity of crucial molecules needed by tumor cells to complete cell division. In this context, we review promising ongoing and future strategies for GBM therapeutics aimed towards G2/M inhibition such as anti-microtubule agents and targeted therapy against G2/M regulators like cyclin-dependent kinases, Aurora inhibitors, PLK1, BUB, 1, and BUBR1, and survivin. Moreover, we also include investigational agents in the preclinical and early clinical settings. Although several drugs were shown to be gliotoxic, most of them have not yet entered therapeutic trials. The use of either single exposure or a combination with novel compounds may lead to treatment alternatives for GBM patients in the near future.

Ginkgetin inhibits growth of breast carcinoma via regulating MAPKs pathway

The purpose of present study was to investigate anti-tumor activity of Ginkgetin (GK) and its mechanism of action in breast cancer. The effects of GK on growth of human breast cancer cell lines MDA-MB-231, BT-474 and MCF-7 were examined by MTT assay. Cells apoptosis in MCF-7 cells were analyzed by TUNEL staining and annexin-V and propidium iodide double staining. The effects of GK on expression of apoptotic associated proteins and mitogen-activated protein kinases (MAPKs) were determined by western blotting. The results showed that GK significantly inhibited proliferation of MDA-MB-231, BT-474 and MCF-7 cells in vitro with time and dose dependent manners and induced apoptosis in MCF-7 cells. GK treatment obviously induced the tumor cells apoptosis and inhibited tumor growth in the MCF-7 xenograft nude mice. GK increased expression of Bax, cleaved-caspase-3, cleaved-caspase-8, cleaved-caspase-9, cleaved-PARP, and decreased the levels of Bcl-2 and survivin in MCF-7 cells. Moreover, GK treatment up-regulated expression of phospho extracellular-related kinase (p-ERK), p-p38 and phospho Jun-amino-terminal kinase (p-JNK) in MCF-7 cells in vitro, and increased numbers of p-p38, p-JNK and p-ERK positive cells in the tumor tissue in vivo. Strikingly, treatment of p38 inhibitor (or JNK inhibitor; ERK inhibitor) significantly prevented GK induced growth inhibition and apoptosis in MCF-7 cells. Collectively, our data exhibit GK exerts well anticancer effects in breast cancer cells, which at least in part, is via activation of the MAPKs. Our results provide a new approach for the treatment of breast cancer.

Molecular docking analysis of aplysin analogs targeting survivin protein

Survivin (IAP proteins) remains an important target for anticancer drug development as it is reported to be over-expressed in tumor cells to enhance resistance to apoptotic stimuli. The study focuses on virtual screening of marine compounds inhibiting survivin, a multifunctional protein, using a computational approach. Structures of compounds were prepared using ChemDraw Ultra 10. Software and converted into its 3D PDB structure and its energy was minimized using Discovery Studio client 2.5. The target protein, survivin was retrieved from RCSB PDB. Lipinski's rule and ADMET toxicity profiling was carried out on marine compounds and the filtered compounds were further promoted for molecular docking analysis and interaction studies using AutoDock Tools 4.0. Molecular docking results revealed that analog (AP 4) of Aplysin, showed very promising inhibitory potential against survivin with a binding energy of -8.75 kcal/mol and Ki 388.28 nM as compared to its known inhibitor, Celecoxib having binding energy of -6.65 kcal/mol and Ki 13.43 μM. AP 4. The analog depicted similarity in pattern when compared to standard. The result proposes AP 4, is an effective molecule exhibiting prominent potential to inhibit survivin and thus promoting apoptosis in tumor cells.

Selinexor (KPT-330) Induces Tumor Suppression through Nuclear Sequestration of IκB and Downregulation of Survivin

Purpose: Selinexor, a small molecule that inhibits nuclear export protein XPO1, has demonstrated efficacy in solid tumors and hematologic malignancies with the evidence of clinical activity in sarcoma as a single agent. Treatment options available are very few, and hence the need to identify novel targets and strategic therapies is of utmost importance.Experimental Design: The mechanistic effects of selinexor in sarcomas as a monotherapy and in combination with proteasome inhibitor, carfilzomib, across a panel of cell lines in vitro and few in xenograft mouse models were investigated.Results: Selinexor induced IκB nuclear localization as a single agent, and the effect was enhanced by stabilization of IκB when pretreated with the proteasome inhibitor carfilzomib. This stabilization and retention of IκB in the nucleus resulted in inhibition of NFκB and transcriptional suppression of the critical antiapoptotic protein, survivin. Treatment of carfilzomib followed by selinexor caused selinexor-sensitive and selinexor-resistant cell lines to be more sensitive to selinexor as determined by an increase in apoptosis. This was successfully demonstrated in the MPNST xenograft model with enhanced tumor suppression.Conclusions: The subcellular distributions of IκB and NFκB are indicative of carcinogenesis. Inhibition of XPO1 results in intranuclear retention of IκB, which inhibits NFκB and thereby provides a novel mechanism for drug therapy in sarcoma. This effect can be further enhanced in relatively selinexor-resistant sarcoma cell lines by pretreatment with the proteasome inhibitor carfilzomib. Because of these results, a human clinical trial with selinexor in combination with a proteasome inhibitor is planned for the treatment of sarcoma. Clin Cancer Res; 23(15); 4301-11. ©2017 AACR.

Nucleobase-modified polyamidoamine-mediated miR-23b delivery to inhibit the proliferation and migration of lung cancer

The nucleobase analogue 2-amino-6-chloropurine was modified on the surface of polyamidoamine (PAMAM) to construct a derivative AP-PAMAM, and then it was used as a gene carrier for miR-23b delivery to achieve the anti-tumor effects.

Downregulation of Survivin by shRNA Inhibits Invasion and Enhances the Radiosensitivity of Laryngeal Squamous Cell Carcinoma

Radiotherapy is an important treatment modality for laryngeal carcinoma, however, some patients with early stage laryngeal carcinomas showed resistance to radiotherapy. Survivin overexpression is associated with radioresistance of laryngeal squamous cell carcinoma. We speculated that the inhibition of survivin expression might improve the radiosensitivity of laryngeal carcinoma. We assessed the effect of survivin expressions by shRNA on the radiosensitivity of laryngeal squamous cell carcinoma in vitro and in vivo. After transfection of shRNA-targeting survivin, MTS assay showed that the survival rates of radiation groups were reduced with the prolongation of culture time (p < 0.05). In addition, shRNA-targeting survivin abrogated radiation-induced G2 phase arrest and amplified radiation-induced apoptosis. In vivo, shRNA transfection also sensitized tumor xenograft to radiotherapy. Radioresistance of laryngeal squamous cell carcinoma may be associated with increased expression of survivin, and survivin suppression may enhance the radiosensitivity of laryngeal squamous cell carcinoma.

miR-138-5p contributes to cell proliferation and invasion by targeting Survivin in bladder cancer cells

Background

Survivin (encoded by the gene BIRC5) plays an important role in the carcinogenesis of bladder cancer. Identifying miRNAs that target Survivin in the setting of bladder cancer will help to develop Survivin-based therapies for bladder cancer.

Methods

The expression levels of miR-138-5p and Survivin protein were measured in 12 resected bladder cancer specimens. The correlation between miR-138-5p and Survivin was further examined by evaluating Survivin expression in human bladder cancer cell lines that either overexpressed or knocked down miR-138-5p. A luciferase reporter assay was performed to test the direct binding of miR-138-5p to the target gene BIRC5. We also investigated the biological role of miR-138-5p targeting to Survivin in bladder cancer cell lines both in vivo and in vitro.

Results

In this study, we found that the Survivin protein was either absent or weakly expressed in normal adjacent tissues and consistently up-regulated in bladder cancer tissues; however, the mRNA levels did not vary as much, suggesting that a post-transcriptional mechanism was involved. Because microRNAs are powerful post-transcriptional regulators of gene expression, we used bioinformatic analyses to search for microRNAs that could potentially target BIRC5 in the setting of bladder cancer. We identified 2 specific targeting sites for miR-138-5p in the 3′ untranslated region (3′-UTR) of BIRC5. We further identified an inverse correlation between miR-138-5p and Survivin protein levels in bladder cancer tissue samples. By overexpressing or knocking down miR-138-5p in bladder cancer cells, we experimentally confirmed that miR-138-5p directly recognizes the 3′-UTR of the BIRC5 transcript and regulates Survivin expression. Furthermore, the biological consequences of the targeting of BIRC5 by miR-138-5p were examined in vitro via cell proliferation and invasion assays and in vivo using a mouse xenograft tumor model. We demonstrated that BIRC5 repression by miR-138-5p suppressed the proliferative and invasive characteristics of bladder cancer cells and that miR-138-5p exerted an anti-tumor effect by negatively regulating BIRC5 in a xenograft mouse model.

Conclusions

Taken together, our findings provide the first clues regarding the role of miR-138-5p as a tumor suppressor in bladder cancer by inhibiting BIRC5 translation.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-016-0569-4) contains supplementary material, which is available to authorized users.

Pro-apoptotic effects of rHSG on C6 glioma cells

Our previous in vitro study demonstrated that the rat hyperplasia suppressor gene (rHSG) inhibited the proliferation of C6 cells. In the present study, we investigated further the effects of rHSG overexpression on the apoptosis of C6 cells and the possible pathways involved. Hoechst 33342/PI double staining and comet assay were used to examine the morphological characteristics of apoptosis and to examine the effects of rHSG on the apoptosis of the C6 cells. Western blot analysis was used to determine the effects of rHSG overexpression on the protein expression levels of poly(ADP-ribose) polymerase (PARP), cleaved caspase-3, phosphorylated extracellular signal-regulated kinase 1/2 (p-Erk1/2), phosphorylated Akt (p-Akt) and phosphoinositide 3-kinase (PI3K)/Akt, as well as on the mitogen-activated protein kinase (MAPK) pathways induced by insulin-like growth factor (IGF)-1. Our results revealed that the C6 cells transfected with the rHSG adenoviral vector (Adv-rHSG-GFP group) efficiently expressed rHSG protein; Hoechst 33342/PI double staining and comet assay revealed that rHSG increased C6 cell apoptosis and induced DNA damage. Western blot analysis indicated that rHSG overexpression significantly increased the level of full-length PARP at 24 and 72 h (P<0.01), but decreased the level at 48 h following transfection (P<0.01), while the proteins levels of cleaved PARP and cleaved caspase-3 increased significantly (P<0.01). The protein expression of p-Erk1/2 and p-Akt began to decrease at 48 h post-transfection (P<0.01). In addition, the protein levels of Akt and Erk1/2 induced by IGF-1 were significantly inhibited. On the whole, the findings of the present study demonstrate that rHSG overexpression induces the apoptosis of rat glioma cells, and that these effects may involve the PI3K/Akt and MAPK pathways.

IWR-1 inhibits epithelial-mesenchymal transition of colorectal cancer cells through suppressing Wnt/β-catenin signaling as well as survivin expression

Aberrant activation of Wnt/β-catenin signaling is frequently observed in patients with colorectal cancer (CRC) and is considered a major determinant of CRC pathogenesis. CRC pathogenesis is particularly accompanied by epithelial-mesenchymal transition (EMT) and survivin expression. Here, we investigated the potential and mechanism of a novel Wnt/β-catenin inhibitor IWR-1 to suppress tumor metastasis in relation with EMT and survivin expression. We first determined the EMT reversal effects of IWR-1 in in vitro (HCT116 and HT29 cells) and ex vivo (specimens of CRC patients) CRC models. It was shown that IWR-1 inhibited cell proliferation and EMT even in the presence of TNF-α-induced cancer cell stimulation. IWR-1 also significantly suppressed cell migration, invasion, and matrix metalloproteinase activities of CRC cell lines. Furthermore, we showed the evidence that IWR-1 provides EMT reversal effects by directly suppressing survivin expression by the followings: 1) IWR-1 could not completely inhibit EMT in survivin-overexpressing HCT116 cells, 2) EMT reversal effects of IWR-1 were more pronounced in survivin-suppressed cells, and 3) Survivin promoter assay directly identified the survivin promoter region responsible for inhibition of survivin transcription by IWR-1. Taken altogether, our results demonstrate that IWR-1 has the potential to suppress tumor metastasis by inhibiting Wnt/β-catenin pathway as well as survivin expression. Therefore, IWR-1 could be considered for future clinical use as a therapeutic agent to treat CRC.

Survivin: a unique target for tumor therapy

Survivin is the smallest member of the Inhibitor of apoptosis (IAP) family of proteins, involved in inhibition of apoptosis and regulation of cell cycle. These functional attributes make Survivin a unique protein exhibiting divergent functions i.e. regulating cell proliferation and cell death. Expression pattern of Survivin is also distinctive; it is prominently expressed during embryonal development, absent in most normal, terminally differentiated tissues but upregulated in a variety of human cancers. Expression of Survivin in tumours correlates with not only inhibition of apoptosis and a decreased rate of cell death, but also resistance to chemotherapy and aggressiveness of tumours. Therefore, Survivin is an important target for cancer vaccines and therapeutics. Survivin has also been found to be prominently expressed on both human and embryonic stem cells and many somatic stem cell types indicating its yet unexplored role in stem cell generation and maintenance. Overall, Survivin emerges as a molecule with much wider role in cellular homeostasis. This review will discuss various aspects of Survivin biology and its role in regulation of apoptosis, cell division, chemo-resistance and tumour progression. Various molecular and immunotherapeutic approaches targeting Survivin will also be discussed.

Norcantharidin induces apoptosis in human prostate cancer cells through both intrinsic and extrinsic pathways

BACKGROUND

Norcantharidin, a modified pure compound from blister beetles, was previously demonstrated to induce apoptosis of cancer cells. This study investigated its anti-cancer activity in prostate cancer cells and the mechanisms involved.

METHODS

Two human prostate cancer cell lines, 22Rv1 and Du145, were treated with norcantharidin at concentrations ranging from 3 to 30μg/ml. Cytotoxic effect of norcantharidin was determined by use of the 3-(4,5-dimethylthiazol-yl)-diphenyl tetrazoliumbromide (MTT) assay. The effects of apoptosis were evaluated by cell death assay, Caspase-3, -8, -9 activity and cytochrome c release. The apoptotic related protein expressions (Bcl-2 family and inhibitor of apoptosis proteins) were determined using western blotting.

RESULTS

An MTT assay revealed that norcantharidin induced cytotoxicity against both prostate cancer cells in dose- and time-dependent manners. Treatment with norcantharidin at 3μg/ml or higher significantly increased oligonucleosomal formation with concomitant appearance of PARP cleavage, implicating the induction of apoptosis. Norcantharidin intrinsically elevated cytosolic cytochrome c levels and activated caspase-3, -8, and -9. Extrinsically, it upregulated the expression of not only the death receptors Fas and DR5 in 22Rv1 cells, but also of RIP and TRADD adaptor proteins in Du145 cells. Mechanistically, norcantharidin increased ratios of pro-/anti-apoptotic proteins and decreased expression of IAP family member proteins, including cIAP1 and survivin, regardless of the distinct status of androgen receptor expression in both cells.

CONCLUSIONS

Norcantharidin exhibited cytotoxicity against 22Rv1 and Du145 prostate cancer cells by inducing both intrinsic and extrinsic apoptotic pathways and could thus potentially be a remedy for prostate cancer.

Design and characterization of the tumor vaccine MGN1601, allogeneic fourfold gene-modified vaccine cells combined with a TLR-9 agonist

The tumor vaccine MGN1601 was designed and developed for treatment of metastatic renal cell carcinoma (mRCC). MGN1601 consists of a combination of fourfold gene-modified cells with the toll-like receptor 9 agonist dSLIM, a powerful connector of innate and adaptive immunity. Vaccine cells originate from a renal cell carcinoma cell line (grown from renal cell carcinoma tissue), express a variety of known tumor-associated antigens (TAA), and are gene modified to transiently express two co-stimulatory molecules, CD80 and CD154, and two cytokines, GM-CSF and IL-7, aimed to support immune response. Proof of concept of the designed vaccine was shown in mice: The murine homologue of the vaccine efficiently (100%) prevented tumor growth when used as prophylactic vaccine in a syngeneic setting. Use of the vaccine in a therapeutic setting showed complete response in 92% of mice as well as synergistic action and necessity of the components. In addition, specific cellular and humoral immune responses in mice were found when used in an allogeneic setting. Immune response to the vaccine was also shown in mRCC patients treated with MGN1601: Peptide array analysis revealed humoral CD4-based immune response to TAA expressed on vaccine cells, including survivin, cyclin D1, and stromelysin.

YM155, a small molecule inhibitor of survivin expression, sensitizes cancer cells to hypericin-mediated photodynamic therapy

Here we show for the first time that the repression of survivin expression by YM155 is effective in sensitizing cancer cells to HY-PDT, as measured by the decrease in cell viability and induction of apoptosis.

Dehydroleucodine inhibits tumor growth in a preclinical melanoma model by inducing cell cycle arrest, senescence and apoptosis

Malignant melanoma represents the fastest growing public health risk of all cancer types worldwide. Several strategies and anti-cancer drugs have been used in an effort to improve treatments, but the development of resistance to anti-neoplastic drugs remains the major cause of chemotherapy failure in melanomas. Previously, we showed that the sesquiterpene lactone, dehydroleucodine (DhL), promotes the accumulation of DNA damage markers, such as H2AX and 53BP1, in human tumor cells. Also DhL was shown to trigger either cell senescence or apoptosis in a concentration-dependent manner in HeLa and MCF7 cells. Here, we evaluated the effects of DhL on B16F0 mouse melanoma cells in vitro and in a pre-clinical melanoma model. DhL inhibited the proliferation of B16F0 cells by inducing senescence or apoptosis in a concentration-dependent manner. Also, DhL reduced the expression of the cell cycle proteins cyclin D1 and B1 and the inhibitor of apoptosis protein, survivin. In melanomas generated by subcutaneous injection of B16F0 cells into C57/BL6 mice, the treatment with 20 mg DhL /Kg/day in preventive, simultaneous and therapeutic protocols reduced tumor volumes by 70%, 60% and 50%, respectively. DhL treatments reduced the number of proliferating, while increasing the number of senescent and apoptotic tumor cells. To estimate the long-term effects of DhL, a mathematical model was applied to fit experimental data. Extrapolation beyond experimental time points revealed that DhL administration following preventive and therapeutic protocols is predicted to be more effective than simultaneous treatments with DhL in restricting tumor growth.

Tanshinone IIA enhances the effects of TRAIL by downregulating survivin in human ovarian carcinoma cells

BACKGROUND

Tanshinone IIA (TIIA), a diterpene quinone from the medicinal plant Salvia miltiorrhiza Bunge (Lamiaceae) was shown to possess apoptotic and TRAIL-sensitizing effects. Still, the molecular mechanisms whereby TIIA induces apoptosis remain largely unknown.

PURPOSE

The role of survivin, an inhibitor of apoptosis protein, in TIIA-induced apoptosis has never been addressed before and hence was the primary goal of this study.

METHODS

In this study, we explored the anticancer effect of TIIA in TOV-21G, SKOV3, and OVCAR3 ovarian carcinoma cells. Cytotoxicity was determined by MTS assay. Real-time RT-PCR and Western blotting were used to assess the mRNA and protein expression of related signaling proteins.

RESULTS

Our results illustrated that TIIA's cytotoxic effect was caused by apoptosis with the involvement of caspases activity. Moreover, TIIA downregulated survivin in a concentration-dependent manner without affecting the expression of Bcl-2, Bcl-xL, and Bax. TIIA-induced survivin downregulation is regulated by both transcriptional processes and proteasomal degradation. Using TOV-21G cells as our cellular model, we demonstrated that TIIA-induced survivin downregulation requires p38 MAPK activation. Importantly, genetic overexpression of survivin rendered cells more resistant to TIIA, indicating an essential role of survivin downregulation in TIIA-induced apoptosis. This TRAIL sensitization effect of TIIA is ascribed to survivin downregulation because the effect was abrogated in cells that overexpressed survivin.

CONCLUSION

Our findings provide new insights into the action modes of TIIA-mediated anticancer effects and further implicate a rational design for cancer therapeutic regimens by combining TIIA-sensitized TRAIL via downregulating survivin to elicit ovarian cancer cell death.

Prognostic significance of survivin, β-catenin and p53 expression in urothelial carcinoma

Survivin, β-catenin, and p53 are well-known cell-cycle and apoptosis regulators of tumorigenesis. Urothelial carcinomas (UCs) are the most common of the human cancers. Compared to superficial tumors (Ta, CIS, or T1), invasive UCs are important with regard to recurrence, progression, and mortality. Therefore, we examined whether survivin, β-catenin, and p53 could be used as the biomarkers for the early prediction of the invasiveness of UCs and the overall survival of the patients. We investigated the prognostic expressions of those biomarkers in UC (n=147) and in non-muscle invasive UC (NMI-UC) (n=113), using tissue microarray and immunohistochemistry. Spearman's correlation analysis and multivariate Cox regression analyses were used for statistical interpretation. High expressions of β-catenin, survivin, and p53 were associated with a high T stage, recurrence, progression, mortality, low recurrence-free survival, low progression-free survival and low overall survival (p <0.01). Similar findings were achieved for recurrence and progression in the NMI-UC group, except for mortality. Moreover, a positive correlation was shown between p53 and β-catenin and between p53 and survivin (r=0.221, p <0.01; r=0.236, p <0.01, respectively). Survivin, p53, and β-catenin overexpression, as prognostic markers, might suggest that the UCs are biologically aggressive with the poor prognosis. Thus, dysregulation of those these cell-cycle and apoptosis regulators in bladder carcinoma could be used as a molecular marker to determine the best treatment strategy and could contribute to the development of targeted therapies.

Transcriptional upregulation of HNF-1β by NF-κB in ovarian clear cell carcinoma modulates susceptibility to apoptosis through alteration in bcl-2 expression

Hepatocyte nuclear factor-1β (HNF-1β) is a transcriptional factor that has an important role in endometriosis-ovarian clear cell carcinoma (OCCC) sequence by modulating cell kinetics and glucose metabolism. However, little is known about the detailed molecular mechanisms that govern its regulation and function. Herein, we focus on upstream and downstream regulatory factors of HNF-1β in OCCCs. In clinical samples, HNF-1β expression was positively correlated with the active form of NF-κB/p65 in OCCCs, and closely linked with a low nuclear grade and non-solid architecture. In cell lines, transfection of p65 resulted in increased HNF-1β mRNA and protein expression in TOV-21G cells (OCCC cell line with endogenous HNF-1β expression), in line with activation of the promoter, probably through interacting with the basic transcriptional machinery. Suppression of endogenous HNF-1β expression by siRNA increased apoptosis in TOV-21G cells, while treatment of Hec251 cells (endometrial carcinoma cell line with extremely low endogenous HNF-1β expression) stably overexpressing exogenous HNF-1β with doxorubicin abrogated apoptosis of the cells, along with increased ratio of bcl-2 relative to bax. Moreover, overexpression of HNF-1β led to upregulation of bcl-2 expression at the transcriptional level in TOV-21G cells, which provided evidence for a positive correlation between HNF-1β and bcl-2 expression in OCCCs. These data, therefore, suggest that association between HNF-1β and NF-κB signaling may participate in cell survival by alteration of apoptotic events, particularly in mitochondria-mediated pathways, through upregulation of bcl-2 expression in OCCCs.