Survivin expression and resistance to anticancer treatments: perspectives for new therapeutic interventions

Prognostic value and therapeutic potential of IAP family in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) ranks as the eighth most prevalent malignancy globally and has the eighth greatest fatality rate when compared to all other forms of cancer. The inhibitor of apoptosis protein (IAP) family comprises a collection of apoptosis-negative modulators characterized by at least one single baculovirus IAP repeat (BIR) domain in its N-terminal region. While the involvement of the IAP family is associated with the initiation and progression of numerous tumours, its specific role in HNSCC remains poorly understood. Thus, this study aimed to comprehensively examine changes in gene expression, immunomodulatory effects, prognosis, and functional enrichment of HNSCC utilising bioinformatics analysis. Elevated levels of distinct IAP family members were observed to varying degrees in HNSCC, with high BIRC2 expression indicating a worse prognosis. Additionally, Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to probe the enrichment of gene expression and biological processes related to the IAP family in HNSCC. The infiltration levels of immune cells were shown to be strongly associated with the IAP gene expression, as determined by subsequent analysis. Hence, BIRC2 could be an effective immunotherapy target for HNSCC. Collectively, novel knowledge of the biological roles and prognostic implications of IAP family members in HNSCC is presented in this study.

Designing Nanomedicines for Breast Cancer Therapy

In 2020, breast cancer became the most diagnosed cancer worldwide. Conventional chemotherapies have major side effects due to their non-specific activities. Alternatively, short interfering RNA(siRNA)-carrying nanoparticles (NPs) have a high potential to overcome this non-specificity. Lipid-substituted polyethyleneimine (PEI) polymers (lipopolymers) have been reported as efficient non-viral carriers of siRNA. This study aims to engineer novel siRNA/lipopolymer nanocomplexes by incorporating anionic additives to obtain gene silencing through siRNA activity with minimal nonspecific toxicity. We first optimized our polyplexes in GFP+ MDA-MB-231 cells to effectively silence the GFP gene. Inclusion of phosphate buffer with pH 8.0 as complex preparation media and N-Lauroylsarcosine Sodium Salt as additive, achieved ~80% silencing with the least amount of undesired cytotoxicity, which was persistent for at least 6 days. The survivin gene was then selected as a target in MDA-MB-231 cells since there is no strong drug (i.e., small organic molecule) for inhibition of its oncogenic activity. The qRT-PCR, flow cytometry analysis and MTT assay revealed >80% silencing, ~95% cell uptake and >70% cell killing by the same formulation. We conclude that our lipopolymer can be further investigated as a lead non-viral carrier for breast cancer gene therapy.

A co-formulation of interferons alpha2b and gamma distinctively targets cell cycle in the glioblastoma-derived cell line U-87MG

BACKGROUND

HeberFERON is a co-formulation of α2b and γ interferons, based on their synergism, which has shown its clinical superiority over individual interferons in basal cell carcinomas. In glioblastoma (GBM), HeberFERON has displayed promising preclinical and clinical results. This led us to design a microarray experiment aimed at identifying the molecular mechanisms involved in the distinctive effect of HeberFERON compared to the individual interferons in U-87MG model.

METHODS

Transcriptional expression profiling including a control (untreated) and three groups receiving α2b-interferon, γ-interferon and HeberFERON was performed using an Illumina HT-12 microarray platform. Unsupervised methods for gene and sample grouping, identification of differentially expressed genes, functional enrichment and network analysis computational biology methods were applied to identify distinctive transcription patterns of HeberFERON. Validation of most representative genes was performed by qPCR. For the cell cycle analysis of cells treated with HeberFERON for 24 h, 48 and 72 h we used flow cytometry.

RESULTS

The three treatments show different behavior based on the gene expression profiles. The enrichment analysis identified several mitotic cell cycle related events, in particular from prometaphase to anaphase, which are exclusively targeted by HeberFERON. The FOXM1 transcription factor network that is involved in several cell cycle phases and is highly expressed in GBMs, is significantly down regulated. Flow cytometry experiments corroborated the action of HeberFERON on the cell cycle in a dose and time dependent manner with a clear cellular arrest as of 24 h post-treatment. Despite the fact that p53 was not down-regulated, several genes involved in its regulatory activity were functionally enriched. Network analysis also revealed a strong relationship of p53 with genes targeted by HeberFERON. We propose a mechanistic model to explain this distinctive action, based on the simultaneous activation of PKR and ATF3, p53 phosphorylation changes, as well as its reduced MDM2 mediated ubiquitination and export from the nucleus to the cytoplasm. PLK1, AURKB, BIRC5 and CCNB1 genes, all regulated by FOXM1, also play central roles in this model. These and other interactions could explain a G2/M arrest and the effect of HeberFERON on the proliferation of U-87MG.

CONCLUSIONS

We proposed molecular mechanisms underlying the distinctive behavior of HeberFERON compared to the treatments with the individual interferons in U-87MG model, where cell cycle related events were highly relevant.

Cloning, Expression, and Purification of the Human Synthetic Survivin Protein in Escherichia coli Using Response Surface Methodology (RSM)

Survivin is one of the novel members of the apoptosis inhibitor protein family in humans. The main activity of the Survivin protein is to suppress caspases activity resulting in negative regulation of apoptosis. Survivin protein can be a potential target for the treatment of cancers between cancerous and normal cells. In the present research, the synthetic Survivin gene with PelB secretion signal peptide was cloned into a prokaryotic expression vector pET21a. The recombinant plasmid pET21a-PelB-Surv was expressed in Escherichia coli (E.coli) BL21, and the relative molecular mass of expressed protein was calculated 34,000 g/mol, approximately. The recombinant protein was purified through chromatography column and characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Response surface methodology (RSM) was used to design 20 experiments for optimization of IPTG concentration, post-induction period, and cell density of induction (OD600). The optimum levels of the selected parameters were successfully determined to be 0.28 mM for IPTG concentration, 10 h for post-induction period, and 3.40768 for cell density (OD600). These findings resulted in 4.14-fold increases in the Survivin production rate of optimum expression conditions (93.6363 mg/ml).

Improved delivery of Mcl-1 and survivin siRNA combination in breast cancer cells with additive siRNA complexes

This study aimed at investigating the influence of commercial transfection reagents (Prime-Fect, Leu-Fect A, and Leu-Fect C) complexed with different siRNAs (CDC20, HSP90, Mcl-1 and Survivin) in MDA-MB-436 breast cancer cells and the impact of incorporating an anionic additive, Trans-Booster, into siRNA formulations for improving in vitro gene silencing and delivery efficiency. Gene silencing was quantitatively analyzed by real-time RT-PCR while cell proliferation and siRNA uptake were evaluated by the MTT assay and flow cytometry, respectively. Amongst the investigated siRNAs and transfection reagents, Mcl-1/Prime-Fect complexes showed the highest inhibition of cell viability and the most effective siRNA delivery. The effect of various formulations on transfection efficiency showed that the additive with 1:1 ratio with siRNA was optimal achieving the lowest cell viability compared to untreated cells and negative control siRNA treatment (p < 0.05). Furthermore, the combination of Mcl-1 and survivin siRNA suppressed the growth of MDA-MB-436 cells more effectively than treatment with the single siRNAs and resulted in cell viability as low as ~ 20% (vs. non-treated cells). This aligned well with the induction of apoptosis as analyzed by flow cytometry, which revealed higher apoptotic cells with the combination treatment group. We conclude that commercial transfection reagents formulated with Mcl-1/Survivin siRNA combination could serve as a potent anti-proliferation agent in the treatment of breast cancers.

Exploring MicroRNA and Exosome Involvement in Malignant Pleural Mesothelioma Drug Response

Malignant pleural mesothelioma (MPM) is a deadly thoracic malignancy and existing treatment options are limited. Chemotherapy remains the most widely used first-line treatment regimen for patients with unresectable MPM, but is hampered by drug resistance issues. The current study demonstrated a modest enhancement of MPM cell sensitivity to chemotherapy drug treatment following microRNA (miRNA) transfection in MPM cell lines, albeit not for all tested miRNAs. This effect was more pronounced for FAK (PND-1186) small molecule inhibitor treatment; consistent with previously published data. We previously established that MPM response to survivin (YM155) small molecule inhibitor treatment is unrelated to basal survivin expression. Here, we showed that MPM response to YM155 treatment is enhanced following miRNA transfection of YM155-resistant MPM cells. We determined that YM155-resistant MPM cells secrete a higher level of exosomes in comparison to YM155-sensitive MPM cells. Despite this, an exosome inhibitor (GW4896) did not enhance MPM cell sensitivity to YM155. Additionally, our study showed no evidence of a correlation between the mRNA expression of inhibitor of apoptosis (IAP) gene family members and MPM cell sensitivity to YM155. However, two drug transporter genes, ABCA6 and ABCA10, were upregulated in the MPM cell lines and correlated with poor sensitivity to YM155.

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.

Nano-Based Drug Delivery and Targeting to Overcome Drug Resistance of Ovarian Cancers

Ovarian cancer (OvCa) is a destructive malignancy due to difficulties in early detection and late advanced-stage diagnoses, leading to high morbidity and mortality rates for women. Currently, the quality treatment for OvCa includes tumor debulking surgery and intravenous platinum-based chemotherapy. However, numerous patients either succumb to the disease or undergo relapse due to drug resistance, such as to platinum drugs. There are several mechanisms that cause cancer cells' resistance to chemotherapy, such as inactivation of the drug, alteration of the drug targets, enhancement of DNA repair of drug-induced damage, and multidrug resistance (MDR). Some targeted therapies, such as nanoparticles, and some non-targeted therapies, such as natural products, reverse MDR. Nanoparticle targeting can lead to the reversal of MDR by allowing direct access for agents to specific tumor sites. Natural products have many anti-cancer properties that adversely regulate the factors contributing to MDR. The present review displays the current problems in OvCa treatments that lead to resistance and proposes using nanotechnology and natural products to overcome drug resistance.

Carbonic Anhydrase IX and Survivin in Colorectal Adenocarcinoma Cells: Slovakian Population Study

Simple Summary

This retrospective study (Slovakian population study) brings information about immunohistochemical detection of CAIX and survivin in 74 samples of human colorectal adenocarcinoma and comparison their expression with expression in healthy colon tissue. Our results show that all of samples with healthy colon tissue were CAIX and survivin-negative and there is no statistically significant dependence of these proteins and the chosen clinicopathological parameters. These findings demonstrate that detection of these proteins could be useful for tumor diagnostic and prognostic and CAIX and survivin could represent independent negative prognostic markers of colorectal cancer.

Abstract

The aim of this study was to detect carbonic anhydrase IX (CAIX) and survivin in the colorectal adenocarcinoma cells of the Slovakian population. We used an indirect three-step immunohistochemical method with DAB staining for the localization of the proteins and investigation their expression. We compared their expression with expression in healthy colorectal tissue. In 74 tissues of colorectal adenocarcinomas, 42% showed CAIX positivity and 20% showed survivin positivity. Brown membrane immunostaining was visible in CAIX-positive tumors. Survivin-positive tumors had strong brown cytoplasmic immunostaining. Co-expression of both proteins was present in five specimens (7%). The samples of normal colorectal tissue (without carcinoma) were CAIX-negative and survivin-negative. We also applied the Chi-squared test for evaluation statistically significant association between the expression of proteins and selected clinical and histopathological parameters. We did not find any statistically significant correlations between CAIX or survivin expression and sex of patients, the grade of the tumor, nodal status and presence of metastasis (p > 0.05). The fact that all samples of normal colorectal tissue were CAIX- and survivin-negative could lead to the possibility of using these two proteins as potential tumor diagnostic markers. On the basic of the available publications and data, we suggest that CAIX and survivin could be negative independent prognostic markers of colorectal cancer, which could affect response to therapy.

The disruption of protein-protein interactions with co-chaperones and client substrates as a strategy towards Hsp90 inhibition

The 90-kiloDalton (kD) heat shock protein (Hsp90) is a ubiquitous, ATP-dependent molecular chaperone whose primary function is to ensure the proper folding of several hundred client protein substrates. Because many of these clients are overexpressed or become mutated during cancer progression, Hsp90 inhibition has been pursued as a potential strategy for cancer as one can target multiple oncoproteins and signaling pathways simultaneously. The first discovered Hsp90 inhibitors, geldanamycin and radicicol, function by competitively binding to Hsp90's N-terminal binding site and inhibiting its ATPase activity. However, most of these N-terminal inhibitors exhibited detrimental activities during clinical evaluation due to induction of the pro-survival heat shock response as well as poor selectivity amongst the four isoforms. Consequently, alternative approaches to Hsp90 inhibition have been pursued and include C-terminal inhibition, isoform-selective inhibition, and the disruption of Hsp90 protein-protein interactions. Since the Hsp90 protein folding cycle requires the assembly of Hsp90 into a large heteroprotein complex, along with various co-chaperones and immunophilins, the development of small molecules that prevent assembly of the complex offers an alternative method of Hsp90 inhibition.

Survivin Promoter-Driven DFF40 Gene Expression Sensitizes Melanoma Cancer Cells to Chemotherapy

Downregulation of the apoptotic protein DNA fragmentation factor 40 (DFF40) is correlated with poor overall survival in some malignancies, including melanoma. In this study, DFF40 gene expression driven by survivin promoter, a tumor-specific promoter, was used to selectively induce cytotoxicity in melanoma cells. The activity and strength of survivin promoter were examined in B16F10 murine melanoma, and L929 murine normal fibroblast cell lines using enhanced green fluorescent protein reporter assay and reverse transcription polymerase chain reaction. The effect of expression of DFF40 under the control of cytomegalovirus (CMV) or survivin promoter on viability of cancerous and normal cells was determined by MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay. Apoptosis induction by expression of DFF40 was evaluated using Annexin-V/propidium iodide staining. Our findings showed high activity of survivin promoter comparable to the control promoter (ie, CMV) in melanoma cells, while survivin activity in normal cells was negligible. Survivin promoter-derived DFF40 gene expression led to selective inhibition of cell viability and induction of apoptosis in cancerous cells. Low and sublethal concentrations of a chemotherapeutic drug, dacarbazine, significantly enhanced the growth inhibitory effect of DFF40 gene therapy. Combination of survivin-driven gene therapy and chemotherapy could be considered as a potential therapeutic treatment for melanoma and possibly other malignancies with similar features.

Unraveling novel survivin mRNA transcripts in cancer cells using an in-house developed targeted high-throughput sequencing approach

The human baculoviral IAP repeat containing 5 (BIRC5), also known as survivin, is a conserved member of the inhibitor of apoptosis protein (IAPs) family, which is normally expressed during embryonic and fetal development. Although the expression levels of survivin are low in terminally differentiated cells and/or tissues, they can be found notably increased in certain pathological conditions including malignant tumors. Conventional cloning and sequencing techniques have already confirmed that alternative splicing events of the survivin pre-mRNA result in five distinct alternative transcript variants. In the present study, however, we implemented an innovative, in-house developed, targeted DNA-seq assay to identify novel survivin alternative transcript variants with increased depth and coverage that high-throughput sequencing approaches offer. Bioinformatics analysis of the derived NGS datasets unveiled several novel splice junctions between annotated exons of survivin gene as well as the existence of a novel exon of 117 nt, spanning between the annotated exons 3 and 3B. Validation of the NGS findings with PCR-based assays, using variant-specific primers, led to the identification of fourteen novel survivin alternative splice variants (BIRC5 v.4 - v.17), which demonstrate wide expression profiles in a broad established panel of human cell lines. Although the presented novel findings provide a crystal-clear overview of the survivin mRNAs that are actually generated from the pre-mRNA, future studies should focus on the impending necessity of characterizing the biological function of all novel alternative transcript variants as well as the putative protein isoforms. Such studies will further contribute to our understanding of how the balance between survivin isoforms regulate malignant cell proliferation and apoptosis, providing novel diagnostic, prognostic and predictive biomarkers as well as therapeutic targets.

Multifunctional DNA Polymer-Assisted Upconversion Therapeutic Nanoplatform for Enhanced Photodynamic Therapy

Although considerable clinical attempts on various kinds of cancers have been made, photodynamic therapy (PDT) still suffers from attenuated therapeutic effects because of the developed resistance of cancer cells. As a novel antiapoptosis protein, survivin has been demonstrated to be selectively overexpressed in a great number of human malignancies and plays a significant part in cancer progression and therapeutic resistance. Herein, we present an upconversion nanoplatform for enhanced PDT by DNAzyme-mediated gene silencing of survivin. In our system, a long single-stranded DNA (ssDNA) with a repetitive aptamer (AS1411) and survivin-targeted DNAzyme was fabricated by rolling circle amplification (RCA) and adsorbed on the upconversion nanoparticles (UCNPs) by electrostatic attraction. The multivalence of the ssDNA endows the upconversion nanoplatform with high recognition and loading capacity of photosensitizers and DNAzymes. When the nanoplatform is targeted internalized into cancer cells, PDT can be triggered by near-infrared (NIR) light to generate reactive oxygen species (ROS) for killing the cancer cells. Moreover, the encoded DNAzyme can efficiently inhibit the gene expression of survivin, providing the potential to enhance the efficiency of PDT. This study thus highlights the promise of an upconversion photodynamic nanoplatform for admirable combination therapy in cancer.

Weight loss normalizes enhanced expression of the oncogene survivin in visceral adipose tissue and blood leukocytes from individuals with obesity

BACKGROUND/OBJECTIVES

Survivin is an oncogene associated with a decrease in apoptosis, an increase in tumor growth, and poor clinical outcome of diverse malignancies. A correlation between obesity, cancer, and survivin is reported in the literature. To date, the impact of weight loss on change in survivin levels is understudied. This study was aimed at: (1) comparing survivin levels in adipose tissue (AT) from lean and obese animal models and evaluating changes after weight loss induced by energy restriction and/or exercise; (2) comparing survivin levels in normal weighted and obese humans and evaluating changes in survivin levels after weight loss induced by a very-low-calorie ketogenic diet (VLCKD) or bariatric surgery in AT and/or blood leukocytes (PBL/PBMCs).

SUBJECTS/METHODS

Survivin expression was evaluated in subcutaneous (SAT) and visceral (VAT) AT derived from animal models of monogenic (Zucker rats) and diet-induced obesity (Sprague Dawley rats and C57BL/6J mice) and after a 4-week weight-loss protocol of energy restriction and/or exercise. Plasma was used to measure the inflammatory status. Survivin expression was also evaluated in PBMCs from patients with obesity and compared with normal weight, in PBLs after VLCKD, and in SAT and/or PBLs after bariatric surgery.

RESULTS

Survivin expression was specifically higher in VAT from obese that lean animals, without differences in SAT. It decreased after weight loss induced by energy restriction and correlated with adiposity and inflammatory markers. In humans, the correlation between being obese and higher levels of survivin was confirmed. In obese subjects, survivin levels were reduced following weight loss after either VLCKD or bariatric surgery. Particularly, a decrease in PBMCs expression (not in SAT one) was found after surgery.

CONCLUSIONS

Weight loss is effective in decreasing survivin levels. Also, PBL/PBMC should be regarded as appropriate mirror of survivin levels in VAT for the identification of an obesity-related protumoral microenvironment.

A role for ceramide glycosylation in resistance to oxaliplatin in colorectal cancer

There is growing evidence to support a role for the ceramide-metabolizing enzyme, glucosylceramide synthase (GCS), in resistance to a variety of chemotherapeutic agents. Whether GCS contributes to oxaliplatin resistance in colorectal cancer (CRC) has not yet been determined. We have addressed this potentially important clinical issue by examining GCS function in two panels of oxaliplatin-resistant, isogenic CRC cell lines. Compared to parental cell lines, oxaliplatin-resistant cells have increased expression of GCS protein associated with increased levels of the pro-survival ceramide metabolite, glucosylceramide (GlcCer). Inhibition of GCS expression by RNAi-mediated gene knockdown resulted in a reduction in cellular GlcCer levels, with restored sensitivity to oxaliplatin. Furthermore, oxaliplatin-resistant CRC cells displayed lower ceramide levels both basally and after treatment with oxaliplatin, compared to parental cells. GlcCer, formed by GCS-mediated ceramide glycosylation, is the precursor to a complex array of glycosphingolipids. Differences in cellular levels and species of gangliosides, a family of glycosphingolipids, were also seen between parental and oxaliplatin-resistant CRC cells. Increased Akt activation was also observed in oxaliplatin-resistant CRC cell lines, together with increased expression of the anti-apoptotic protein survivin. Finally, this study shows that GCS protein levels are greatly increased in human CRC specimens, compared to matched, normal colonic mucosa, and that high levels of UGCG gene expression are significantly associated with decreased disease-free survival in colorectal cancer patients. These findings uncover an important cellular role for GCS in oxaliplatin chemosensitivity and may provide a novel cellular target for augmenting chemotherapeutic drug effectiveness in CRC.

Survivin Promotes Piperlongumine Resistance in Ovarian Cancer

Ovarian cancer is one of the most fatal female malignancies while targeting apoptosis is critical for improving ovarian cancer patients' lives. Survivin is regarded as the most robust anti-apoptosis protein, and its overexpression in ovarian cancer is related to poor survival and apoptosis resistance. Piperlongumine (PL) extracted from peppers is defined as an active alkaloid/amide and exhibits a broad spectrum of antitumor effects. Here, we demonstrate that PL induces the rapid depletion of survivin protein levels via reactive oxygen species (ROS)-mediated proteasome-dependent pathway in vitro, while exerting a remarkable inhibitory influence on the proliferation of ovarian cancer cells. Overexpression of survivin raises the survival rate of ovarian cancer cells to PL. Moreover, PL inhibits ovarian cancer cells xenograft tumor growth and downregulates survivin in vivo. Our findings reveal a previously unrecognized mechanism of PL in suppressing survivin expression as well as survivin promotes piperlongumine resistance in ovarian cancer and suggest that ROS-mediated proteasome-dependent pathway can be exploited to overcome apoptosis resistance triggered by aberrant expression of survivin.

Epigenetic reprogramming and potential application of epigenetic-modifying drugs in acquired chemotherapeutic resistance

Chemotherapy is the most common clinical choice of treatment for cancer, however, acquired chemoresistance is a major challenge that limits the successful outcome of this option. Systematic review of in vitro, in vivo, preclinical and clinical studies suggests that acquired chemoresistance is polygenic, progressive, and involve both genetic and epigenetic heterogeneities and perturbations. Various mechanisms that confer resistance to chemotherapy are tightly controlled by epigenetic regulations. Poised epigenetic plasticity and temporal increase in epigenetic alterations upon chemotherapy make chemoresistance likely an epigenetic-driven process. The transient and reversible nature of epigenetic modulations enable ways to intervene the epigenetic re-programing associated with acquired chemoresistance via application of epigenetic modifying drugs. This review discusses recent understandings behind the various mechanisms of acquired chemoresistance that are under the control of epigenetic drivers, potential application of epigenetic-based drugs in resensitizing refractory cancers to chemotherapy, the limitations and future scope for clinical application of epigenetic therapeutics in successfully addressing chemoresistance.

An Inhibitor of the Interaction of Survivin with Smac in Mitochondria Promotes Apoptosis

Herein we report the first small molecule that disrupts the survivin-Smac interaction taking place in mitochondria. The inhibitor, PZ-6-QN, was identified by initially screening a phenothiazine library using a fluorescence anisotropy assay and then conducting a structure-activity relationship study. Mutagenesis and molecular docking studies suggest that PZ-6-QN binds to survivin similarly to the known Smac peptide, AVPI. The results of the effort also show that PZ-6-QN exhibits good anticancer activity against various cancer cells. Moreover, cell-based mechanistic studies provide evidence for the proposal that PZ-6-QN enters mitochondria to inhibit the survivin-Smac interaction and promotes release of Smac and cytochrome c from mitochondria into the cytosol, a process that induces apoptosis in cancer cells. Overall, the present study suggests that PZ-6-QN can serve as a novel chemical probe for study of processes associated with the mitochondrial survivin-Smac interaction and it will aid the discovery of novel anticancer agents.

Response prediction to oxaliplatin plus 5-fluorouracil chemotherapy in patients with colorectal cancer using a four-protein immunohistochemical model

The response of cancer patients to oxaliplatin combined with 5-fluorouracil (5-FU) is difficult to predict. It has been reported that carcinoma-associated fibroblasts (CAFs) could induce AKT and ERK phosphorylation, and upregulate survivin expression in colorectal cancer (CRC) cells, which could lead to oxaliplatin plus 5-FU resistance. A total of 71 patients with advanced CRC (aCRC) treated with oxaliplatin plus 5-FU were included in the present study. These patients comprised 46 chemotherapy responders and 25 non-responders. The expression levels of α-smooth muscle actin (α-SMA), phosphorylated (p)-AKT, p-ERK and survivin were determined by immunohistochemical evaluation of paraffin-embedded samples from patients. A predictive model was established using a Probabilistic Neural Network model. The high expression of α-SMA, p-AKT and survivin in patients with aCRC were associated with oxaliplatin plus 5-FU resistance (P<0.001, P=0.023 and P=0.001, respectively). Furthermore, patients with stage IV CRC exhibiting high expression levels of α-SMA and survivin experienced a reduced progression-free survival time compared with patients with low expressions of α-SMA and survivin (5.5 vs. 15.0 months; 5.5 vs. 15.0 months; P=0.005 and P=0.001, respectively). Stage IV CRC and high survivin expression predicted a reduced overall survival time compared with that for patients with stage IV CRC and low survivin expression (50.0 vs. 15.0 months; P<0.001). Patients with α-SMA, p-AKT, p-ERK and survivin overexpression were more likely to present with intrinsic resistance to the oxaliplatin plus 5-FU regimen (the accuracies of modeling, validation and prediction were 83.7, 92.9 and 85.7%, respectively). In conclusion, the multifactorial predictive biomarker model of α-SMA, p-AKT, p-ERK and survivin expression for patients with aCRC to predict intrinsic resistance to oxaliplatin plus 5-FU regimens is of great efficiency and accuracy. Patients with high expression of this predictive model may be intrinsically resistant to the oxaliplatin and 5-FU regimen.

siRNA-Conjugated Nanoparticles to Treat Ovarian Cancer

Ovarian cancer is the fifth-most lethal cancer among women due to a lack of early detection and late-stage treatment options, and it is responsible for more than 14,000 deaths each year in the United States. Recently, there have been advances in RNA interference therapy, specifically with small interfering RNA (siRNA), to reduce tumor burden for ovarian cancer via gene down-regulation. However, delivery of siRNA poses its own challenges, as siRNA is unstable in circulation, is unable to be effectively internalized by cells, and may cause toxicity in off-target sites. To address such challenges, nanoparticle carriers have emerged as delivery platforms for the biocompatible, targeted delivery of siRNA-based therapies. Several preclinical studies have shown the promising effects of siRNA therapy to reduce chemotherapy resistance and proliferation of ovarian cancer cells. This review evaluates the recent advances, clinical applications, and future potential of nanoparticle-mediated delivery of siRNA therapeutics to target genes implicated in ovarian cancer.

Butein induces apoptotic cell death of human cervical cancer cells

Butein is a chalcone, a flavonoid that is widely biosynthesized in plants. Butein has been identified to possess varied pharmacological activity and is extractable from traditional Chinese medicinal herbs, therefore applicable for disease treatment. Recently, in vitro and in vivo studies have shown that butein may induce apoptotic cell death in various human cancer cells. In this study we investigated the apoptotic effect of butein and the underlying mechanisms in human cervical cancer cells. Two cell lines, C-33A and SiHa cells, were treated with butein at different dosages for different durations. The effect of butein on cell viability was assessed by MTT assay, which revealed that butein exerted cytotoxicity in both cervical cancer cells in a dose- and time-dependent fashion. Apoptotic pathway-related factors in the butein-treated cervical cancer cells were then examined. JC-1 flow cytometry, cytochrome c assay, and caspase activity assays demonstrated that butein disturbed mitochondrial transmembrane potential, and increased cytosolic cytochrome c levels and caspase activities in both cervical cancer cells. Western blot analysis revealed that butein downregulated anti-apoptotic protein Bcl-xL and led to proteolytic cleavage of poly (ADP-ribose) polymerase. In addition, butein decreased expressions of the inhibitor of apoptosis (IAP) proteins, including X-linked IAP, survivin, and cellular IAP-1. The findings of this study suggest that butein can decrease cervical cancer cell viability via a pro-apoptotic effect, which involves inhibition of the IAP proteins and activation of both extrinsic and intrinsic pro-apoptotic pathways. Therefore, butein may be applicable for cervical cancer treatment.

Smart polymeric nanoparticles with pH-responsive and PEG-detachable properties for co-delivering paclitaxel and survivin siRNA to enhance antitumor outcomes

Background

The co-delivery of chemotherapeutic agents and small interfering RNA (siRNA) within one cargo can enhance the anticancer outcomes through its synergistic therapeutic effects.

Materials and methods

We prepared smart polymeric nanoparticles (NPs) with pH-responsive and poly(ethylene glycol) (PEG)-detachable properties to systemically co-deliver paclitaxel (PTX) and siRNA against survivin gene for lung cancer therapy. The cationic polyethyleneimine-block-polylactic acid (PEI-PLA) was first synthesized and characterized, with good biocompatibility. PTX was encapsulated into the hydrophobic core of the PEI-PLA polymers by dialysis, and then the survivin siRNA was loaded onto the PTX-loaded NPs (PEI-PLA/PTX) through electrostatic interaction between siRNA and PEI block. Finally, the negatively charged poly(ethylene glycol)-block-poly(L-aspartic acid sodium salt) (PEG-PAsp) was coated onto the surface of NPs by electrostatic interaction to form final smart polymeric NPs with mean particle size of 82.4 nm and zeta potential of 4.1 mV. After uptake of NPs by tumor cells, the PEG-PAsp segments became electrically neutral owing to the lower endosome pH and consequently detached from the smart NPs. This process allowed endosomal escape of the NPs through the proton-sponge effect of the exposed PEI moiety.

Results

The resulting NPs achieved drug loading of 6.04 wt% and exhibited good dispersibility within 24 h in 10% fetal bovine serum (FBS). At pH 5.5, the NPs presented better drug release and cellular uptake than at pH 7.4. The NPs with survivin siRNA effectively knocked down the expression of survivin mRNA and protein owing to enhanced cell uptake of NPs. Cell counting kit-8 (CCK-8) assay showed that the NPs presented low systemic toxicity and improved antiproliferation effect of PTX on A549 cells. Moreover, in vivo studies demonstrated that accumulated NPs in the tumor site were capable of inhibiting the tumor growth and extending the survival rate of the mice by silencing the survivin gene and delivering PTX into tumor cells simultaneously.

Conclusion

These results indicate that the prepared nano-vectors could be a promising co-delivery system for novel chemo/gene combination therapy.

Survivin knockdown induces senescence in TTF‑1-expressing, KRAS-mutant lung adenocarcinomas

Survivin plays a key role in regulating the cell cycle and apoptosis, and is highly expressed in the majority of malignant tumors. However, little is known about the roles of survivin in KRAS-mutant lung adenocarcinomas. In the present study, we examined 28 KRAS-mutant lung adenocarcinoma tissues and two KRAS-mutant lung adenocarcinoma cell lines, H358 and H441, in order to elucidate the potential of survivin as a therapeutic target. We found that 19 (68%) of the 28 KRAS-mutant lung adenocarcinomas were differentiated tumors expressing thyroid transcription factor-1 (TTF-1) and E-cadherin. Patients with tumors immunohistochemically positive for survivin (n=18) had poorer outcomes than those with survivin-negative tumors (n=10). In the H358 and H441 cells, which expressed TTF-1 and E-cadherin, survivin knockdown alone induced senescence, not apoptosis. However, in monolayer culture, the H358 cells and H441 cells in which survivin was silenced, underwent significant apoptosis following combined treatment with ABT-263, a Bcl-2 inhibitor, and trametinib, a MEK inhibitor. Importantly, the triple combination of survivin knockdown with ABT-263 and trametinib treatment, clearly induced cell death in a three-dimensional cell culture model and in an in vivo tumor xenograft model. We also observed that the growth of the H358 and H441 cells was slightly, yet significantly suppressed in vitro when TTF-1 was silenced. These findings collectively suggest that the triple combination of survivin knockdown with ABT-263 and trametinib treatment, may be a potential strategy for the treatment of KRAS-mutant lung adenocarcinoma. Furthermore, our findings indicate that the well-differentiated type of KRAS-mutant lung tumors depends, at least in part, on TTF-1 for growth.

MicroRNA-mediated epigenetic targeting of Survivin significantly enhances the antitumor activity of paclitaxel against non-small cell lung cancer

Elevated expression of Survivin correlates with poor prognosis, tumor recurrence, and drug resistance in various human cancers, including non-small cell lung cancer (NSCLC). The underlying mechanism of Survivin upregulation in cancer cells remains elusive. To date, no Survivin-targeted therapy has been approved for cancer treatment. Here, we explored the molecular basis resulting in Survivin overexpression in NSCLC and investigated the antitumor activity of the class I HDAC inhibitor entinostat in combination with paclitaxel. Our data showed that entinostat significantly enhanced paclitaxel-mediated anti-proliferative/anti-survival effects on NSCLC cells in vitro and in vivo. Mechanistically, entinostat selectively decreased expression of Survivin via induction of miR-203 (in vitro and in vivo) and miR-542-3p (in vitro). Moreover, analysis of NSCLC patient samples revealed that the expression levels of miR-203 were downregulated due to promoter hypermethylation in 45% of NSCLC tumors. In contrast, increased expression of both DNA methytransferase I (DNMT1) and Survivin was observed and significantly correlated with the reduced miR-203 in NSCLC. Collectively, these data shed new lights on the molecular mechanism of Survivin upregulation in NSCLC. Our findings also support that the combinatorial treatments of entinostat and paclitaxel will likely exhibit survival benefit in the NSCLC patients with overexpression of DNMT1 and/or Survivin. The DNMT1-miR-203-Survivin signaling axis may provide a new avenue for the development of novel epigenetic approaches to enhance the chemotherapeutic efficacy against NSCLC.

Tumor expression of survivin, p53, cyclin D1, osteopontin and fibronectin in predicting the response to neo-adjuvant chemotherapy in children with advanced malignant peripheral nerve sheath tumor

PURPOSE

Selected cell-cycle regulators and extracellular matrix proteins were found to play roles in malignant peripheral nerve sheath tumor (MPNST) biology. We aimed to analyze whether initial tumor tissue expressions of survivin, p53, cyclin D1, osteopontin (OPN) and fibronectin (FN) correlate with the response to neo-adjuvant CHT (naCHT) in children with advanced inoperable MPNST.

METHODS

The study included 26 children with MPNST (M/F 14/12, median age 130 months) treated in Polish centers of pediatric oncology between 1992 and 2013. Tissue expression of markers was studied immunohistochemically in the manually performed tissue microarrays and assessed semi-quantitatively as low and high, based on the rate of positive cells and staining intensity.

RESULTS

Good response to naCHT was noted in 47.6%, while poor-in 52.4% of patients. The response to naCHT was influenced negatively by the presence of neurofibromatosis NF1 and high initial tumor tissue expression of OPN, survivin, p53 and cyclin D1. Patients with high tumor expression of either OPN, survivin or p53 and those with simultaneous high expression of ≥ 3 of the markers, responded significantly worse to naCHT, than patients, in whom expression of ≤ 2 markers were detected at diagnosis. Nearly, 85% of patients expressing ≥ 3 markers, responded poor to CHT; while 87.5% of children, expressing ≤ 2 markers, were good responders.

CONCLUSION

The initial tumor tissue expression of OPN, survivin, p53 and cyclin D1 may serve as markers to predict response to naCHT in pediatric advanced MPNST. Future studies in more numerous group of patients are needed to confirm these preliminary results.

Epigenetic mechanism of survivin dysregulation in human cancer

Survivin (coding gene BIRC5) is a dual functional protein acting as a critical inhibitor of apoptosis (IAP) and key regulator of cell cycle progression. It is usually produced in embryonic tissues during development and undetectable in most adult tissues. Overexpression of Survivin frequently occurs in various human cancers and increased Survivin correlates with poor clinic outcome, tumor recurrence, and therapeutic resistance. Because of its selective expression in tumor, but not normal tissues, Survivin has been recognized as an attractive target for cancer treatment. Although several therapeutic approaches targeting Survivin are actively under clinical trials in human cancers, to date no Survivin-targeted therapy has been approved for cancer treatment. Numerous studies have devoted to uncovering the underlying mechanism resulting in Survivin dysregulation at multiple levels, such as transcriptional and post-transcriptional regulation. The current article provides a literature review on the transcriptional and epigenetic regulation of Survivin expression in human cancers. We focus on the impact of DNA methylation and histone modifications, including specific lysine methylation, demethylation, and acetylation on the expression of Survivin. The latest development of epigenetic approaches targeting Survivin for cancer treatment are also discussed.

Enhancement of chemosensitivity by simultaneously silencing of Mcl-1 and Survivin genes using small interfering RNA in human myelomonocytic leukaemia

Acute myeloid leukaemia (AML) is a genetically heterogeneous, severe and rapidly progressing disease triggered by blocking granulocyte or monocyte differentiation and maturation. Overexpression of myeloid cell leukaemia-1 (Mcl-1) and Survivin is associated with drug resistance, tumour progression and inhibition of apoptotic mechanisms in leukaemia and several cancers. In the present study, we examined the combined effect of etoposide and dual siRNA-mediated silencing of Mcl-1 and Survivin on U-937 AML cells. The AML cells were co-transfected with Mcl-1 and Survivin-specific siRNAs and genes silencing were confirmed by quantitative real-time PCR and Western blotting. Subsequently, MTT assay was used for the evaluation of cytotoxic effects by dual siRNA and etoposide on their own and in combination. For the studying of apoptosis, DNA-histone ELISA and annexin-V/FITC assays were performed. Co-transfection of Mcl-1 and Survivin siRNA significantly blocked their expression at the mRNA and protein levels, leading to the induction of apoptosis and strong inhibition of growth (p < .05). Besides, combined treatment of etoposide with Mcl-1 and Survivin siRNAs co-transfection leads to synergistically enhance etoposide-induced cytotoxic and apoptotic effects (p < .05). The results showed that Mcl-1 and Survivin play a major role in the U937 cells survival and their resistance relative to etoposide. Thus, Mcl-1 and Survivin can be considered as promising molecular targets for the treatment of AML. The combination treatment with etoposide, and siRNA-mediated silencing of corresponding genes may be a novel strategy in chemoresistance AML treatment.

Subcellular Localization of Survivin Determines Its Function in Cardiomyocytes

Rationale:Reducing cardiomyocyte death and enhancing their proliferation after myocardial infarction is perhaps the single largest challenge for cardiac tissue regeneration. Survivin (SVV) is the smallest member of the inhibitor of apoptosis (IAP) family but plays two important roles; inhibiting caspase-9 activation in the intrinsic apoptosis pathway, and regulating microtubule dynamics and chromosome segregation during cell division. Genetic depletion of cardiac SVV leads to incomplete cardiomyocyte division and abnormal heart development. However, the function of SVV in adult hearts after myocardial infarction remains unclear.

Methods: A homozygous inducible cardiomyocyte-specific SVV knockout transgenic mouse model was established through crossbreeding SVV^flox/flox and αMHC-MCM transgenic mice. Adult mice received consecutive intraperitoneal injection of tamoxifen to induce genetic removal of SVV in cardiomyocytes. A SVV overexpressing model was established via local delivery of SVV in wild-type mouse hearts.

Results: We found that 30.82% of cardiomyocytes in the peri-infarct region of SVV knockout mice were apoptotic, significantly higher than the 22.18% in control mice. In addition, ejection fraction was 29.00±0.40% in knockout mice compared to 38.04±0.50% in control mice 21 days after myocardial infarction. On the contrary, locally overexpressing SVV in the heart improved cardiac functions. Unexpectedly, we found that altering the subcellular localization of SVV overexpression produced different outcomes. Overexpression of SVV in the cytoplasm decreased cardiomyocyte apoptosis, whereas overexpression of SVV in the nucleus enhanced cardiac regeneration. The ejection fraction of mice overexpressing SVV was 36.58±0.91%, significantly higher than 28.18±1.70% in the GFP control group. Apoptotic cardiomyocytes were only 4.63% in mouse overexpressing cytosolic SVV, compared to 9.31% in the GFP group, and activation of caspase-3 was also reduced. Moreover, mice overexpressing NLS-SVV exhibited a better ejection fraction (36.19±1.02%,) than GFP controls (26.69±0.75%). NLS-SVV enhanced H3P-positive cardiomyocytes in the border zone to 0.28%, compared to only 0.08% in GFP group, through interacting with Aurora B.

Conclusions:We demonstrate the importance of SVV subcellular localization in regulating post-MI cardiac repair and regeneration. We hope that this will open new translational approaches through targeted delivery of SVV.

Palbociclib, a selective CDK4/6 inhibitor, enhances the effect of selumetinib in RAS-driven non-small cell lung cancer

KRAS is one of the most commonly mutated oncogenes in non-small cell lung cancer (NSCLC). Resistance to MEK inhibitor monotherapy develops through a variety of mechanisms. CDK4 was reported to have a synthetic lethal interaction with KRAS. In this study, we demonstrated the combination effects of the MEK inhibitor selumetinib and the CDK4/6 inhibitor palbociclib in RAS-driven NSCLC. In vitro, cell lines with CDKN2A mutations were insensitive to selumetinib. We used siRNA and pharmacologic inhibition of CDK4 and found that the combination of selumetinib and palbociclib synergistically inhibited RAS-driven NSCLC cases with CDKN2A mutations but not those with wild type CDKN2A. The combination treatment potentiated growth inhibition and increased the population of cells in G1 phase. Selumetinib completely inhibited p-ERK but not p-RB. The addition of palbociclib markedly inhibited p-RB and downregulated survivin expression. In vivo, the combination treatment inhibited the growth of NSCLC xenografts, which correlated with decreased levels of p-RB, downregulated survivin and decreased Ki-67 staining. These data suggest that the combination treatment of palbociclib and selumetinib is effective in preclinical models of RAS-driven NSCLC with CDKN2A mutations.

Evaluation of antitumor activity of survivin short interfering RNA delivered by lipid nanoparticles in colon cancer in vitro and in vivo

Survivin has been overexpressed in numerous types of cancer and is associated with a poor clinical outcome. A number of various approaches have been used to counteract survivin in order to inhibit tumor growth or promote cell apoptosis. The present study aimed to evaluate the efficiency and antitumor effect of a survivin-targeted short interfering RNA (siRNA) delivery system using lipid nanoparticles for the treatment of colon cancer. Survivin siRNA (si-survivin) nanoliposomes were prepared and transfected into LoVo cells. The mRNA expression level of survivin was determined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Cell viability was evaluated by MTT assay. LoVo-bearing nude mice were treated with si-survivin intratumorally or intravenously. Tumor growth in LoVo-bearing mice was monitored and recorded, and tumor samples were obtained for evaluation of survivin expression levels using RT-qPCR, western blotting and immunohischemical staining. The expression level of survivin was significantly reduced by nanoliposomal si-survivin along with cell proliferation inhibition in vitro. Intravenous administration of si-survivin nanoliposomes may significantly inhibit tumor growth with less toxicity compared with doxorubicin hydrochloride treatment in LoVo-bearing mice. Nanoliposomal si-survivin may significantly reduce the expression level of survivin and inhibit cell proliferation of colon cancer cells in vitro and in vivo. si-survivin delivered by lipid nanoparticles may be a potential treatment approach for colon cancer.

Small interfering RNA targeting of the survivin gene inhibits human tumor cell growth in vitro

The present study aimed to evaluate the impact of small interfering RNA (siRNA) targeting of the survivin gene in human tumor cells and the effect of decreased survivin expression on the proliferation and apoptosis of tumor cells. Human tumor cell lines (MSA-MB-231, SGC-7901, HeLa, A549, SK-OV-3 and Raji, PC-3) were cultured in vitro and divided into three groups: survivin siRNA-treated, scrambled negative control siRNA-treated and an untreated control group. The level of survivin mRNA and protein expression was subsequently determined by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. Cell proliferation was also examined by an MTT assay following transfection and the apoptotic rate of cells was detected by Hoechst and Annexin V/propidium iodide staining. It was observed that relative to the control group, expression of survivin mRNA and protein in the survivin siRNA-treated group was significantly downregulated. Furthermore, siRNA targeting of survivin lead to the inhibition of tumor cell proliferation, as well as an increase in their apoptotic rate in vitro. These data suggest that survivin may be a potential tumor biomarker and a novel target for the treatment of cancer.

Novel targets for paclitaxel nano formulations: Hopes and hypes in triple negative breast cancer

Triple negative breast cancer is defined as one of the utmost prevailing breast cancers worldwide, possessing an inadequate prognosis and treatment option limited to chemotherapy and radiotherapy, creating a challenge for researchers as far as developing a specific targeted therapy is concerned. The past research era has shown several promising outcomes for TNBC such as nano-formulations of the chemotherapeutic agents already used for the management of the malignant tumor. Taking a glance at paclitaxel nano formulations, it has been proven beneficial in several researches in the past decade; nevertheless its solubility is often a challenge to scientists in achieving success. We have henceforth discussed the basic heterogeneity of triple negative breast cancer along with the current management options as well as a brief outlook on pros and cons of paclitaxel, known as the most widely used chemotherapeutic agent for the treatment of the disease. We further analyzed the need of nanotechnology pertaining to the problems encountered with the current paclitaxel formulations available discussing the strategic progress in various nano-formulations till date taking into account the basic research strategies required in terms of solubility, permeability, physicochemical properties, active and passive targeting. A thorough review in recent advances in active targeting for TNBC was carried out whereby the various ligands which are at present finding its way into TNBC research such as hyaluronic acid, folic acid, transferrin, etc. were discussed. These ligands have specific receptor affinity to TNBC tumor cells hence can be beneficial for novel drug targeting approaches. Conversely, there are currently several novel strategies in the research pipeline whose targeting ligands have not yet been studied. Therefore, we reviewed upon the numerous novel receptor targets along with the respective nano-formulation aspects which have not yet been fully researched upon and could be exemplified as outstanding target strategies for TNBC which is currently an urgent requirement.

HMGI-C suppressing induces P53/caspase9 axis to regulate apoptosis in breast adenocarcinoma cells

PURPOSE

The HMGI-C (high mobility group protein isoform I-C) protein is a member of the high-mobility group AT-hook (HMGA) family of small non-histone chromosomal proteins that can modulate transcription of an ample number of genes. Genome-wide studies reveal upregulation of the HMGI-C gene in many human cancers, which suggests that HMGI-C might play a critical role in the progression of various tumors. However, the exact role of HMGI-C in breast adenocarcinoma has not been made clear.

METHODS

HMGI-C mRNA expression in breast cancer samples and marginal normal tissues was characterized using qRT-PCR. The cytotoxic effects of HMGI-C siRNA on breast adenocarcinoma cells were determined using MTT assay. Relative HMGI-C mRNA and protein levels were measured by quantitative real-time PCR and western blotting, respectively. Apoptosis detection was done using TUNEL and Annexin-V/PI assays, P53, caspase 3, 9, 8 and Bcl2 proteins evaluated by protein gel blot and miR34a, Let-7a genes investigates by QRT-PCR assay. Cell cycle was analyzed by flow cytometry assay using propidium iodide DNA staining.

RESULTS

An overexpression of HMGA2 was revealed with highly statistically significant differences between breast cancer samples and marginal normal tissues (P < 0.0001). HMGI-C siRNA significantly reduced both mRNA and protein expression levels in a 48-hour period after transfection and in a dose-dependent manner. We observed that the knockdown of HMGI-C led to the significant induction of apoptosis via mitochondrial pathway by inducing miR34a and cell cycle arrest in MDA-MB-468 cells in vitro.

CONCLUSIONS

These results propose that HMGI-C might play a critical role in the progression of breast adenocarcinoma. Here we introduced HMGI-C as a potential therapeutic target for trigger apoptosis and cell cycle arrest in human breast adenocarcinoma. Therefore HMGI-C siRNA may be an effective adjuvant in human breast adenocarcinoma.

JAK2 inhibitor TG101348 overcomes erlotinib-resistance in non-small cell lung carcinoma cells with mutated EGF receptor

Non-small cell lung cancer (NSCLC) patients with epidermal growth factor receptor (EGFR) mutations are responsive to EGFR-tyrosine kinase inhibitor (EGFR-TKI). However, NSCLC patients with secondary somatic EGFR mutations are resistant to EGFR-TKI treatment. In this study, we investigated the effect of TG101348 (a JAK2 inhibitor) on the tumor growth of erlotinib-resistant NSCLC cells. Cell proliferation, apoptosis, gene expression and tumor growth were evaluated by diphenyltetrazolium bromide (MTT) assay, flow cytometry, terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) staining, Western Blot and a xenograft mouse model, respectively. Results showed that erlotinib had a stronger impact on the induction of apoptosis in erlotinib-sensitive PC-9 cells but had a weaker effect on erlotinib-resistant H1975 and H1650 cells than TG101348. TG101348 significantly enhanced the cytotoxicity of erlotinib to erlotinib-resistant NSCLC cells, stimulated erlotinib-induced apoptosis and downregulated the expressions of EGFR, p-EGFR, p-STAT3, Bcl-xL and survivin in erlotinib-resistant NSCLC cells. Moreover, the combined treatment of TG101348 and erlotinib induced apoptosis, inhibited the activation of p-EGFR and p-STAT3, and inhibited tumor growth of erlotinib-resistant NSCLC cells in vivo. Our results indicate that TG101348 is a potential adjuvant for NSCLC patients during erlotinib treatment.

Delivery of a survivin promoter-driven antisense survivin-expressing plasmid DNA as a cancer therapeutic: a proof-of-concept study

Survivin is a member of the inhibitor-of-apoptosis proteins family. It is overexpressed in many different cancer types but not in the differentiated normal tissue. In addition, overexpression of survivin promotes cancer cell survival and induces chemotherapeutic drug resistance, making it an attractive target for new anticancer interventions. Despite survivin being a promising molecular target for anticancer treatment, it is widely accepted that survivin is only a "semi-druggable" target. Therefore, it is important to develop a new strategy to target survivin for anticancer treatment. In this study, we constructed a novel survivin promoter-driven full-length antisense survivin (pSur/AS-Sur) expression plasmid DNA. Promoter activity assay revealed that the activity of the survivin promoter of pSur/AS-Sur correlated with the endogenous expression of survivin at the transcriptional level in the transfected A549, MDA-MB-231, and PANC-1 cancer cells. Western blot analysis showed that liposomal delivery of pSur/AS-Sur successfully downregulated the expression of survivin in A549, MBA-MB-231, and PANC-1 cells in vitro. In addition, delivery of pSur/AS-Sur induced autophagy, caspase-dependent apoptosis, and caspase-independent apoptosis as indicated by the increased LC3B-II conversion, autophagosome formation, caspase-9/-3 and poly(ADP-ribose) polymerase-1 cleavage, and apoptosis-inducing factor nuclear translocation in A549, MBA-MB-231, and PANC-1 cells. Importantly, liposomal delivery of pSur/AS-Sur was also capable of decreasing the proliferation of the survivin/MDR1 coexpressing multidrug-resistant KB-TAX50 cancer cells and the estrogen receptor-positive tamoxifen-resistant MCF7-TamC3 cancer cells in vitro. In conclusion, the results of this study suggest that delivery of a survivin promoter-driven antisense survivin-expressing plasmid DNA is a promising way to target survivin and to treat survivin-expressing cancers in the future.

Physcion 8-O-β-glucopyranoside induces mitochondria-dependent apoptosis of human oral squamous cell carcinoma cells via suppressing survivin expression

AIM

A previous study has shown that physcion 8-O-β-glucopyranoside (PG) derived from Rumex japonicusHoutt causes apoptosis and blocks cell cycle progression in human lung cancer cells. In the present study we investigated the molecular mechanisms underlying PG-induced cancer cell apoptosis.

METHODS

Human OSCC-derived cell line KB was treated PG (10, 20, 50 μg/mL). Cell apoptosis was detected with flow cytometry. Mitochondrial membrane potential (MMP) and release of cytochome C from mitochondria were measured; the expression of relevant signaling proteins was analyzed using Western blotting or qRT-PCR. For evaluation of in vivo anticancer action, nude mice grafted with KB cells were treated with PG (10, 20, 40 mg·kg(-1)·d(-1), ip) for 24 days.

RESULTS

PG dose-dependently suppressed cell proliferation and induced apoptosis in KB cells. PG-induced apoptosis was mediated via the intrinsic mitochondrial pathway, as evidenced by the decreased Bcl-2, increased Bax and Bax/Bcl-2 ratio, as well as the loss of MMP, caspase-9 activation, and increased cytosolic cytochrome c. Furthermore, PG suppressed the expression of survivin, whereas overexpression of survivin markedly attenuated PG-induced apoptosis. Meanwhile PG increased the expression of tumor suppressor PTEN, and decreased p-Akt, p-GSK3β and miR-21 levels. Pharmacological activation of Akt/GSK3β signaling or transfection with miR-21 mimic abolished PG-induced survivin reduction and cell apoptosis. Similar results were observed in PG-treated nude mice grafted with KB cells.

CONCLUSION

Physcion 8-O-β-glucopyranoside induces mitochondria-dependent apoptosis of human OSCC cells by suppressing survivin expression via miR-21/PTEN/Akt/GSK3β signaling pathway.

Curcumin enhances the cytogenotoxic effect of etoposide in leukemia cells through induction of reactive oxygen species

Curcumin may exert a more selective cytotoxic effect in tumor cells with elevated levels of free radicals. Here, we investigated whether curcumin can modulate etoposide action in myeloid leukemia cells and in normal cells of hematopoietic origin. HL-60 cell line, normal myeloid progenitor cluster of differentiation (CD)-34⁺ cells, and granulocytes were incubated for 4 or 24 hours at different concentrations of curcumin and/or etoposide. Brown Norway rats with acute myeloid leukemia (BNML) were used to prove the influence of curcumin on etoposide action in vivo. Rats were treated with curcumin for 23 days and etoposide was administered for the final 3 days of the experiment. Curcumin synergistically potentiated the cytotoxic effect of etoposide, and it intensified apoptosis and phosphorylation of the histone H2AX induced by this cytostatic drug in leukemic HL-60 cells. In contrast, curcumin did not significantly modify etoposide-induced cytotoxicity and H2AX phosphorylation in normal CD34⁺ cells and granulocytes. Curcumin modified the cytotoxic action of etoposide in HL-60 cells through intensification of free radical production because preincubation with N-acetyl-l-cysteine (NAC) significantly reduced the cytotoxic effect of curcumin itself and a combination of two compounds. In contrast, NAC did not decrease the cytotoxic effect of etoposide. Thus, oxidative stress plays a greater role in the cytotoxic effect of curcumin than that of etoposide in HL-60 cells. In vitro results were confirmed in a BNML model. Pretreatment with curcumin enhanced the antileukemic activity of etoposide in BNML rats (1.57-fold tumor reduction versus etoposide alone; P<0.05) and induced apoptosis of BNML cells more efficiently than etoposide alone (1.54-fold change versus etoposide alone; P<0.05), but this treatment protected nonleukemic B-cells from apoptosis. Thus, curcumin can increase the antileukemic effect of etoposide through reactive oxygen species in sensitive myeloid leukemia cells, and it is harmless to normal human cells.

MicroRNA-218 is a prognostic indicator in colorectal cancer and enhances 5-fluorouracil-induced apoptosis by targeting BIRC5

One major reason for the failure of advanced colorectal cancer (CRC) treatment is the occurrence of chemoresistance to fluoropyrimidine (FU)-based chemotherapy. Various reports showed that ectopic expression and function of microRNAs (miRNAs) played key roles to mediate apoptosis at the post-transcriptional level. To further explore the possible mechanisms, we evaluated the prognostic effect of miR-218 in patients with CRC receiving 5-FU-based treatment and investigated the proapoptotic role of miR-218 in vitro. Primary tumour specimens and adjacent non-tumour sites were used to determine miR-218 expression distribution and explore its potential prognostic value in response to 5-FU-based treatment in patients with CRC. HCT116 and HT29 cells were transfected with precursor miR-218 or negative control, followed by assays to investigate its influence on apoptosis, cell proliferation and pathways involved in molecular mechanisms of chemoresistance to 5-FU. Results showed that high miR-218 expression was associated with positive response to firstline 5-FU treatment in CRC patients. MiR-218 promoted apoptosis, inhibited cell proliferation and caused cell cycle arrest in CRC cells by suppressing BIRC5 expression. Furthermore, miR-218 enhanced 5-FU cytotoxicity in CRC cells by suppressing the 5-FU targeted enzyme, thymidylate synthase (TS). In conclusion, we demonstrated that high miR-218 expression had a positive prognostic value in 5-FU-based treatments for CRC patients and discovered a novel mechanism mediated by miR-218 to promote apoptosis and to function synergistically with 5-FU to promote chemosensitivity by suppressing BIRC5 and TS in CRC. These suggest the unique potential of miR-218 as a novel candidate for developing miR-218-based therapeutic strategies in CRC.

Serum Survivin Levels and Outcome of Chemotherapy in Patients with Malignant Mesothelioma

BACKGROUND

Survivin is an inhibitor of apoptosis protein involved in the regulation of cell proliferation that could be used as a marker for cancer diagnosis or prognosis. Our aim was to evaluate whether serum survivin levels influence the outcome of cisplatin-based chemotherapy in patients with malignant mesothelioma (MM).

METHODS

Serum survivin levels were determined using human survivin enzyme-linked immunosorbent assay in 78 MM patients before chemotherapy, after chemotherapy, and at disease progression. The influence on tumor response and survival was evaluated using nonparametric tests and Cox regression.

RESULTS

A median serum survivin level at diagnosis was 4.1 (0-217.5) pg/mL. Patients with a progressive disease had significantly higher survivin levels before chemotherapy (p = 0.041). A median serum survivin level after chemotherapy was 73.1 (0-346.2) pg/mL. If survivin levels increased after chemotherapy, patients had, conversely, better response (p = 0.001, OR = 5.40, 95% CI = 1.98-14.72). Unexpectedly, patients with increased survivin levels after chemotherapy also had longer progression-free (p < 0.001, HR = 0.33, 95% CI = 0.20-0.57) and overall survival (p = 0.001, HR = 0.29, 95% CI = 0.14-0.58).

CONCLUSIONS

These results suggest that serum survivin levels before and during chemotherapy could serve as a biomarker predicting MM treatment response.

Butein Shows Cytotoxic Effects and Induces Apoptosis in Human Ovarian Cancer Cells

Butein is a polyphenol, one of the compounds of chalcones, which are flavonoids that are widely biosynthesized in plants, and exhibits different pharmacological activities. Plants containing butein have been used in Chinese traditional medicine. Recently, it has been reported that butein suppresses proliferation and triggers apoptosis in various human cancer cells in vitro and in vivo. The aim of this study was to investigate its pro-apoptotic effect and mechanisms in two cultured human ovarian cancer cells (ES-2 and TOV-21G). The effects of butein on cell viability were assessed by a MTT assay at 3, 10, 30, and 100 μ/M. The apoptotic pathway related factors, including the mitochondrial transmembrane potential (MTP), cytochrome c, caspase cascade, and Bcl-2 family proteins, were examined. MTT assay revealed that butein was cytotoxic to both ovarian cancer cells in a dose- and time-dependent manner. JC-1 flow cytometry, cytochrome c, and caspase activity assays revealed that butein damaged the MTP, increased the level of cytosol cytochrome c and the activities of caspase-3, -8, and -9 in the two ovarian cancer cells. Western blot analysis revealed that butein down-regulated the anti-apoptotic proteins Bcl-2 and Bcl-xL and increased the pro-apoptotic proteins Bax and Bad. These findings suggest that butein-induced apoptosis in ovarian cancer cells via the activation of both extrinsic and intrinsic pathways. In addition, butein also down-regulated the expressions of the inhibitor of apoptosis (IAP) proteins, XIAP, survivin, CIAP-1, and CIAP-2. This indicates that the inhibition of IAP proteins was also involved in butein-induced apoptosis. The results of our study suggest that butein may be a promising anticancer agent in treating ovarian cancer.

Influence of survivin-targeted therapy on chemosensitivity in the treatment of acute myeloid leukemia

Overexpression of survivin is observed in various hematological malignancies, including acute myeloid leukemia (AML). Studies show that elevated expression of survivin correlates with a worse clinic outcome in AML patients. It remains unclear whether inhibition of survivin may alter the efficacy of chemotherapy against AML. Here, we evaluate the effects of specific knockdown of survivin on AML cells' sensitivity to chemotherapy, and investigate the therapeutic potential of the transcription inhibitor of survivin YM155 either alone or in combination with chemotherapeutic agents. We found Kasumi-1 and HL-60 cells had relatively higher expression levels of survivin among all AML cell lines tested. Specific knockdown of survivin in Kasumi-1 and HL-60 cells resulted in: inhibition of cell proliferation; cell cycle G2/M arrest; induction of DNA damage response and apoptosis. Downregulation of survivin enhanced etoposide- or doxorubicin-induced anti-proliferative/anti-survival activity in AML cells. The small molecule inhibitor YM155 reduced survivin in a dose- and time-dependent manner and trigged apoptosis in Kasumi-1 and HL-60 cells. The combinatorial effects of YM155 and chemotherapeutics were either synergetic or antagonistic, depending upon the drugs used for combination and the type of AML cells being treated. Collectively, our data demonstrate that survivin plays an important role in the maintenance and proliferation of AML cells. While specific knockdown of survivin enhances chemosensitivity, the combinations of YM155 and chemotherapeutic agents exhibit synergetic or antagonistic effects on AML cells. Our findings provide a rationale for further assessment of survivin-targeted therapy in the treatment of patients with AML.

Evaluation of survivin splice variants in pituitary tumors

PURPOSE

Survivin is an apoptosis inhibitor, expressed in almost all types of human malignancies, but rarely in differentiated normal tissues. Recently, survivin gene splice variants with different anti-apoptotic activities have been reported. The current study was undertaken to examine the expression of survivin and its splice variants ∆Ex3 and 2β in pituitary tumors, and to correlate the amount of particular transcripts with clinical staging in pituitary adenomas. Quantitative detection of survivin and its splice variants ∆Ex3 and 2β transcripts in non-cancerous pituitary tissues (n = 12) and different types of pituitary tumor (n = 50).

METHODS

Samples were collected from 50 pituitary tumors including 26 non-functional tumors, 21 GH-secreting tumors, 2 PRL-secreting tumors and 1 ACTH-secreting tumor. 12 normal pituitary glands received after autopsy served as a control of the study. 29 thyroid cancers tissues were used as a positive control. The RT-qPCR with TaqMan hydrolysis probes were used to determine the expression of analyzed splice variants of survivin.

RESULTS

The obtained data showed that both survivin and its splice variants were expressed in different types of pituitary adenoma as well as in normal pituitary tissue. However, the level of its expression was similar in all studied cases. Patient age negatively correlated with tumor invasiveness. Moreover, our study showed a tendency for negative correlation between patient age and tumor diameter.

CONCLUSIONS

No significant differences between survivin and its splice variants ∆Ex3 and 2β expression in pituitary tumors and in normal pituitary glands as well as in invasive and in non-invasive tumors were found, suggesting that survivin does not play a significant role in pituitary tumorigenesis.