Nanotechnology based platforms for survivin targeted drug discovery

Advances in nanotechnology-based platforms for survivin-targeted drug discovery

INTRODUCTION

Due to its unique functional impact on multiple cancer cell circuits including proliferation, apoptosis, tumor dissemination, DNA damage repair and immune response, the inhibitor of apoptosis protein (IAP) survivin has gained high interest as a molecular target and a multitude of therapeutics were developed to interfere with survivin expression and functionality. First clinical evaluations of these therapeutics, however, were disappointing highlighting the need to develop advanced delivery systems of survivin-targeting molecules to increase stability, bioavailability as well as the selective guidance to tumor tissue.

AREAS COVERED

: This review focuses on advancements in nanocarriers to molecularly target survivin in human malignancies. A plethora of nanoparticle platforms, including liposomes, polymeric systems, dendrimers, inorganic nanocarriers, RNA/DNA nanotechnology and exosomes are discussed in the background of survivin-tailored RNA interference, small molecule inhibitors, dominant negative mutants or survivin vaccination or combined modality treatment with chemotherapeutic drugs and photo- dynamic/photothermal strategies.

EXPERT OPINION

Novel therapeutic approaches include the use of biocompatible nanoformulations carrying gene silencing or drug molecules to directly or indirectly target proteins, allow for a more precise and controlled delivery of survivin therapeutics. Moreover, surface modification of these nanocarriers may result in a tumor entity specific delivery. Therefore, nanomedicine exploiting survivin-tailored strategies in a multimodal background is considered the way forwaerd to enhance the development of future personalized medicine.

Recent advances in nanomedicine and survivin targeting in brain cancers

Brain cancer is a highly lethal disease, especially devastating toward both the elderly and children. This cancer has no therapeutics available to combat it, predominately due to the blood-brain barrier (BBB) preventing treatments from maintaining therapeutic levels within the brain. Recently, nanoparticle technology has entered the forefront of cancer therapy due to its ability to deliver therapeutic effects while potentially passing physiological barriers. Key nanoparticles for brain cancer treatment include glutathione targeted PEGylated liposomes, gold nanoparticles, superparamagnetic iron oxide nanoparticles and nanoparticle-albumin bound drugs, with these being discussed throughout this review. Recently, the survivin protein has gained attention as it is over-expressed in a majority of tumors. This review will briefly discuss the properties of survivin, while focusing on how both nanoparticles and survivin-targeting treatments hold potential as brain cancer therapies. This review may provide useful insight into new brain cancer treatment options, particularly survivin inhibition and nanomedicine.

Efficient inhibition of ovarian cancer by degradable nanoparticle-delivered survivin T34A gene

Gene therapy has promising applications in ovarian cancer therapy. Blocking the function of the survivin protein could lead to the growth inhibition of cancer cells. Herein, we used degradable heparin–polyethyleneimine (HPEI) nanoparticles to deliver a dominant-negative human survivin T34A (hs-T34A) gene to treat ovarian cancer. HPEI nanoparticles were characterized and were found to have a dynamic diameter of 66±4.5 nm and a zeta potential of 27.1±1.87 mV. The constructed hs-T34A gene expression plasmid could be effectively delivered into SKOV3 ovarian carcinoma cells by HPEI nanoparticles with low cytotoxicity. Intraperitoneal administration of HPEI/hs-T34A complexes could markedly inhibit tumor growth in a mouse xenograft model of SKOV3 human ovarian cancer. Moreover, according to our results, apparent apoptosis of cancer cells was observed both in vitro and in vivo. Taken together, the prepared HPEI/hs-T34A formulation showed potential applications in ovarian cancer gene therapy.

Cissus quadrangularis inhibits IL-1β induced inflammatory responses on chondrocytes and alleviates bone deterioration in osteotomized rats via p38 MAPK signaling

INTRODUCTION

Inflammatory mediators are key players in the pathogenesis of osteoarthritis (OA) and bone destruction. Conventional drugs suppress symptomatic activity and have no therapeutic influence on disease. Cissus quadrangularis and Withania somnifera are widely used for the treatment of bone fractures and wounds; however, the cellular and molecular mechanisms regulated by these herbals are still unclear.

METHODS

We established an in vitro OA culture model by exposing human chondrocytes to proinflammatory cytokine and interleukin (IL)-1β for 36 hours prior to treatment with the herbals: C. quadrangularis, W. somnifera, and the combination of the two herbals. Cell viability, toxicity, and gene expression of OA modifying agents were examined. In addition, expression of survivin, which is crucial for cell growth, was analyzed. In vivo work on osteotomized rats studied the bone and cartilage regenerative effects of C. quadrangularis, W. somnifera, and the combination therapy.

RESULTS

Exposure of chondrocytes to IL-1β induced significant toxicity and cell death. However, herbal treatment alleviated IL-1β induced cell toxicity and upregulated cell growth and proliferation. C. quadrangularis inhibited gene expression of cytokines and matrix metalloproteinases, known to aggravate cartilage and bone destruction, and augmented expression of survivin by inhibiting p38 MAPK. Interestingly, osteotomized rats treated with C. quadrangularis drastically enhanced alkaline phosphatase and cartilage tissue formation as compared to untreated, W. somnifera only, or the combination of both herbals.

CONCLUSION

Our findings demonstrate for the first time the signaling mechanisms regulated by C. quadrangularis and W. somnifera in OA and osteogenesis. We suggest that the chondroprotective effects and regenerative ability of these herbals are via the upregulation of survivin that exerts inhibitory effects on the p38 MAPK signaling pathway. These findings thus validate C. quadrangularis as a potential therapeutic for rheumatic disorders.

Iron-free and iron-saturated bovine lactoferrin inhibit survivin expression and differentially modulate apoptosis in breast cancer

BACKGROUND

Iron binding, naturally occurring protein bovine lactoferrin (bLf) has attracted attention as a safe anti-cancer agent capable of inducing apoptosis. Naturally, bLf exists partially saturated (15-20%) with Fe(3+) however, it has been demonstrated that manipulating the saturation state can enhance bLf's anti-cancer activities.

METHODS

Apo-bLf (Fe(3+) free) and Fe-bLf (>90% Fe(3+) Saturated) were therefore, tested in MDA-MB-231 and MCF-7 human breast cancer cells in terms of cytotoxicity, proliferation, migration and invasion. Annexin-V Fluos staining was also employed in addition to apoptotic protein arrays and Western blotting to determine the specific mechanism of bLf-induced apoptosis with a key focus on p53 and inhibitor of apoptosis proteins (IAP), specifically survivin.

RESULTS

Apo-bLf induced significantly greater cytotoxicity and reduction in cell proliferation in both cancer cells showing a time and dose dependent effect. Importantly, no cytotoxicity was detected in normal MCF-10-2A cells. Both forms of bLf significantly reduced cell invasion in cancer cells. Key apoptotic molecules including p53, Bcl-2 family proteins, IAP members and their inhibitors were significantly modulated by both forms of bLf, though differentially in each cell line. Most interestingly, both Apo-bLf and Fe-bLf completely inhibited the expression of survivin protein (key IAP), after 48 h at 30 and 40 nM in cancer cells.

CONCLUSIONS

The capacity of these forms of bLf to target survivin expression and modulation of apoptosis demonstrates an exciting potential for bLf as an anti-cancer therapeutic in the existing void of survivin inhibitors, with a lack of successful inhibitors in the clinical management of cancer.

Nuclear survivin expression: a prognostic factor for the response to taxane-platinum chemotherapy in patients with advanced non-small cell lung cancer

Survivin, a structurally unique protein expressed in most common human neoplasms, is thought to support cell cycle progression and suppress apoptosis. Survivin expression is highly correlated with advanced non-small cell lung cancer (NSCLC) and poor prognosis. In this retrospective study of banked pathology tissue of patients with advanced NSCLC, we tested for correlations of N-survivin expression in tumor tissues and responsiveness to treatment with platinum-based regimens containing paclitaxel or docetaxel. The 48 patients with NSCLC included 32 (66.7 %) males and 16 (33.3 %) females. Mean age at diagnosis was 59.4 years (range 36-83 years), and median follow-up time was 20.4 months (range 3.4-59.0 months). Patients with high tumor N-survivin expression had significantly better responses to taxane-platinum chemotherapy than those with low tumor N-survivin expression (P < 0.001). Adjusted multivariate modeling found high tumor N-survivin expression to be an independent prognostic factor for a clinical response to chemotherapy (high vs. low, OR 6.14, 95 % CI 1.62-23.29; P = 0.008). Median overall survival differed significantly between those with high tumor N-survivin expression who did/did not respond to chemotherapy and between those with low tumor N-survivin expression who did/did not respond to chemotherapy (P < 0.05). Tumor N-survivin expression shows promise as a predictive biomarker in the chemotherapy setting as a surrogate marker of high proliferation status.

Defining a prognostic marker panel for patients with ovarian serous carcinoma effusion

Advanced-stage ovarian carcinoma is a highly lethal malignancy, yet no widely accepted prognostic panels exist to date in this disease. The objective of this study was to define such panel for patients with ovarian serous carcinoma effusions. The expression by immunohistochemistry and clinical role of 41 previously studied cancer-associated proteins was analyzed in 143 effusions from patients diagnosed as having advanced-stage (International Federation of Gynecology and Obstetrics stages III-IV) ovarian serous carcinoma treated with platinum-based chemotherapy at diagnosis. Survival analyses were performed separately for patients with prechemotherapy and postchemotherapy effusions. In univariate analysis of patients with primary diagnosis prechemotherapy effusions, survivin was associated with longer progression-free survival (P = .03), whereas survivin (P = .009), signal transducer and activator of transcription 5B (P = .011), and p21-activated kinase-1 (P = .04) were markers of longer overall survival. In univariate analysis of patients with disease recurrence postchemotherapy effusions, peroxisome proliferator-activated receptor-γ (P = .004), human leukocyte antigen-G (P = .013), mammalian target of rapamycin (P = .04), and nucleus accumbens 1 (NAC-1) (P = .046) were associated with poor progression-free survival, whereas peroxisome proliferator-activated receptor-γ (P = .013), claudin-3 (P = .019), activator protein-2γ (P = .04), insulin-like growth factor-2 (P = .04), claudin-7 (P = .042), and fatty acid synthase (P = .048) were markers of poor overall survival. In Cox multivariate analysis for prechemotherapy cases, survivin and fatty acid synthase were independent predictors of better progression-free survival (P = .006 and P = .048, respectively), and signal transducer and activator of transcription 5B and heat shock protein 90 were independently associated with better overall survival (P = .033 and P = .006, respectively). None of the biological markers was an independent prognostic factor in recurrent disease. The present study represents the first attempt at prognostic stratification of multiple tumor markers in one cohort of patients with ovarian serous carcinoma effusions.

Use of Nanotechnology to Develop Multi-Drug Inhibitors For Cancer Therapy

Therapeutic agents that inhibit a single target often cannot combat a multifactorial disease such as cancer. Thus, multi-target inhibitors (MTIs) are needed to circumvent complications such as the development of resistance. There are two predominant types of MTIs, (a) single drug inhibitor (SDIs) that affect multiple pathways simultaneously, and (b) combinatorial agents or multi-drug inhibitors (MDIs) that inhibit multiple pathways. Single agent multi-target kinase inhibitors are amongst the most prominent class of compounds belonging to the former, whereas the latter includes many different classes of combinatorial agents that have been used to achieve synergistic efficacy against cancer. Safe delivery and accumulation at the tumor site is of paramount importance for MTIs because inhibition of multiple key signaling pathways has the potential to lead to systemic toxicity. For this reason, the development of drug delivery mechanisms using nanotechnology is preferable in order to ensure that the MDIs accumulate in the tumor vasculature, thereby increasing efficacy and minimizing off-target and systemic side effects. This review will discuss how nanotechnology can be used for the development of MTIs for cancer therapy and also it concludes with a discussion of the future of nanoparticle-based MTIs as well as the continuing obstacles being faced during the development of these unique agents.’