Expression and targeting of the apoptosis inhibitor, survivin, in human melanoma

Do Tumor SURVIVIN and MDM2 Expression Levels Correlate with Treatment Response and Clinical Outcome in Isolated Limb Perfusion for In-Transit Cutaneous Melanoma Metastases?

Isolated limb perfusion (ILP) involves the local administration of high doses of anticancer drugs into a limb affected by unresectable locally advanced tumors (with special regard to in-transit melanoma metastases), minimizing systemic side effects. Tumor response to anticancer drugs may depend on the expression of apoptosis-related genes, such as SURVIVIN and MDM2. This retrospective cohort study investigated the association between tumor SURVIVIN and MDM2 expression levels and treatment response or clinical outcomes in patients undergoing ILP for in-transit melanoma metastases. The study cohort consisted of 62 patients with in-transit metastases who underwent ILP with tumor necrosis factor (TNF) and melphalan. Tissue samples were taken from the in-transit metastases, and RNA was extracted for gene expression analysis. Patients' response to treatment was assessed using clinical and radiological criteria two months after ILP, and disease response was classified as complete, partial, or stable/progressive disease. Disease-free survival (DFS) and overall survival (OS) were also analyzed. Expression of SURVIVIN and/or MDM2 was observed in 48% of patients; in these cases, complete response to ILP occurred in 40% of cases, with the overall response rate (complete + partial) being 85%. Patients with expression of MDM2 alone had a lower complete response rate (28%), while patients with expression of SURVIVIN alone had a higher complete response rate (50%). The combined expression of MDM2 and SURVIVIN resulted in a complete response rate of 30%. Patients without expression (of SURVIVIN or MDM2) had the highest complete response rate (58%). Survival analysis showed that high MDM2 expression was independently associated with a lower probability of a complete response to ILP. In addition, patients with MDM2 expression were three times more likely to have an incomplete response to ILP. This study highlights the importance of considering SURVIVIN and MDM2 expression in patients undergoing ILP for in-transit cutaneous melanoma metastases. High MDM2 expression was found to be an independent factor associated with a reduced likelihood of achieving a complete response to ILP, suggesting potential mechanisms of chemoresistance. These data support further research to explore the role of already available targeted therapies (i.e., MDM2 inhibitors) in improving tumor response to ILP in patients with in-transit melanoma metastases.

Dual role of deubiquitinating enzyme USP19 regulates mitotic progression and tumorigenesis by stabilizing survivin

Survivin is a component of the chromosomal passenger complex, which includes Aurora B, INCENP, and Borealin, and is required for chromosome segregation and cytokinesis. We performed a genome-wide screen of deubiquitinating enzymes for survivin. For the first time, we report that USP19 has a dual role in the modulation of mitosis and tumorigenesis by regulating survivin expression. Our results found that USP19 stabilizes and interacts with survivin in HCT116 cells. USP19 deubiquitinates survivin protein and extends its half-life. We also found that USP19 functions as a mitotic regulator by controlling the downstream signaling of survivin protein. Targeted genome knockout verified that USP19 depletion leads to several mitotic defects, including cytokinesis failure. In addition, USP19 depletion results in significant enrichment of apoptosis and reduces the growth of tumors in the mouse xenograft. We envision that simultaneous targeting of USP19 and survivin in oncologic drug development would increase therapeutic value and minimize redundancy.

Antineoplastic Properties by Proapoptotic Mechanisms Induction of Inula viscosa and Its Sesquiterpene Lactones Tomentosin and Inuviscolide

Cancer is a complex disease including approximately 200 different entities that can potentially affect all body tissues. Among the conventional treatments, radiotherapy and chemotherapy are most often applied to different types of cancers. Despite substantial advances in the development of innovative antineoplastic drugs, cancer remains one of the most significant causes of death, worldwide. The principal pitfall of successful cancer treatment is the intrinsic or acquired resistance to therapeutic agents. The development of more effective or synergistic therapeutic approaches to improve patient outcomes and minimize toxicity has become an urgent issue. Inula viscosa is widely distributed throughout Europe, Africa, and Asia. Used as a medicinal plant in different countries, I. viscosa has been characterized for its complex chemical composition in order to identify the bioactive compounds responsible for its biological activities, including anticancer effects. Sesquiterpene lactones (SLs) are natural, biologically active products that have attracted considerable attention due to their biological activities. SLs are alkylating agents that form covalent adducts with free cysteine residues within enzymes and key proteins favoring cancer cell cytotoxicity. They are effective inducers of apoptosis in several cancer cell types through different molecular mechanisms. This review focuses on recent advances in the cytotoxic effects of I. viscosa and SLs in the treatment of neoplastic diseases, with a special emphasis on their proapoptotic molecular mechanisms.

Apoptosis and Pharmacological Therapies for Targeting Thereof for Cancer Therapeutics

Apoptosis is an evolutionarily conserved sequential process of cell death to maintain a homeostatic balance between cell formation and cell death. It is a vital process for normal eukaryotic development as it contributes to the renewal of cells and tissues. Further, it plays a crucial role in the elimination of unnecessary cells through phagocytosis and prevents undesirable immune responses. Apoptosis is regulated by a complex signaling mechanism, which is driven by interactions among several protein families such as caspases, inhibitors of apoptosis proteins, B-cell lymphoma 2 (BCL-2) family proteins, and several other proteases such as perforins and granzyme. The signaling pathway consists of both pro-apoptotic and pro-survival members, which stabilize the selection of cellular survival or death. However, any aberration in this pathway can lead to abnormal cell proliferation, ultimately leading to the development of cancer, autoimmune disorders, etc. This review aims to elaborate on apoptotic signaling pathways and mechanisms, interacting members involved in signaling, and how apoptosis is associated with carcinogenesis, along with insights into targeting apoptosis for disease resolution.

Anticancer and Anti-Inflammatory Effects of Tomentosin: Cellular and Molecular Mechanisms

Tomentosin is a natural compound known for its presence in some medicinal plants of the Asteraceae family such as Inula viscosa. Recent studies have highlighted its anticancer and anti-inflammatory properties. Its anticancer mechanisms are unique and act at different levels ranging from cellular organization to molecular transcriptional factors and epigenetic modifications. Tomentosin’s possession of the modulatory effect on telomerase expression on tumor cell lines has captured the interest of researchers and spurred a more robust study on its anticancer effect. Since inflammation has a close link with cancer disease, this natural compound appears to be a potential cancer-fighting drug. Indeed, its recently demonstrated anti-inflammatory action can be considered as a starting point for its evaluation as an anticancer chemo-preventive agent

A Novel Recombinant Fcγ Receptor-Targeted Survivin Combines with Chemotherapy for Efficient Cancer Treatment

Formyl peptide receptor-like 1 inhibitor (FLIPr), an Fcγ receptor (FcγR) antagonist, can be used as a carrier to guide antigen-FLIPr fusion protein to FcγR then enhances antigen-specific immune responses. Survivin, a tumor-associated antigen, is over-expressed in various types of human cancer. In this study, we demonstrate that recombinant survivin-FLIPr fusion protein (rSur-FLIPr) binds to FcγRs, and efficient uptake by dendritic cells in vivo. In addition, rSur-FLIPr alone stimulates survivin-specific immune responses, which effectively suppresses the tumor growth. The antitumor immunities are through TAP-mediated and CD8-dependent pathways. Furthermore, preexisting anti-FLIPr antibody does not abolish antitumor responses induced by rSur-FLIPr immunization. These results suggest that FLIPr is an effective antigen delivery vector and can be repeatedly used. Combination of chemotherapy with rSur-FLIPr treatment reveals a great benefit to tumor-bearing mice. Altogether, these findings suggest that rSur-FLIPr is a potential candidate for efficient cancer therapy.

Apoptosis Detection Methods in Diagnosis of Cancer and Their Potential Role in Treatment: Advantages and Disadvantages: a Review

INTRODUCTION

Interruption of regulation of apoptosis can play a leading role in cancers where elevated apoptosis causes neurodegeneration, autoimmunity, AIDS, and ischemia. One famous example can be p53's downregulation, which is a tumor suppressor gene, which consequently can cause a decrease in apoptosis rate and intense tumor growth and progression and development and inactivation of 53; it can be extended to many cancers in human. Anyhow, apoptosis is a double-edge sword. There are many trials and studies are going on observation and understanding of different steps involved in apoptosis. Apoptosis has a very major role in carcinogenesis and the treatment of cancer.

AIM

In this updated-cum-comprehensive review, we would like to cover what is apoptosis and cancer and also, will discuss all known methods of apoptosisdetection, their applicability in the treatment of cancer, and their advantages, disadvantages, and limitations.

MATERIAL AND METHODS

Published articles on indexing sources such as PubMed, Scopus from 2000 to date.

RESULT

By considering all above information including each methods pros and cons, these routine methods could be great tool with distinctive qualities in treatmentwhich can be great help from patient perspective and as well from government ad health care system point of view.

CONCLUSION

Accurate diagnosis of cell apoptotic biopathways at different stages assists in evaluating near to exact apoptotic index, which is the perfect sign andindicator for metastasis and also prognosis, thus foreseeing treatment outcome.

Nucleic acids therapeutics using PolyPurine Reverse Hoogsteen hairpins

PolyPurine Reverse Hoogsteen hairpins (PPRHs) are DNA hairpins formed by intramolecular reverse Hoogsteen bonds which can bind to polypyrimidine stretches in dsDNA by Watson:Crick bonds, thus forming a triplex and displacing the fourth strand of the DNA complex. PPRHs were first described as a gene silencing tool in vitro for DHFR, telomerase and survivin genes. Then, the effect of PPRHs directed against the survivin gene was also determined in vivo using a xenograft model of prostate cancer cells (PC3). Since then, the ability of PPRHs to inhibit gene expression has been explored in other genes involved in cancer (BCL-2, mTOR, topoisomerase, C-MYC and MDM2), in immunotherapy (SIRPα/CD47 and PD-1/PD-L1 tandem) or in replication stress (WEE1 and CHK1). Furthermore, PPRHs have the ability to target the complementary strand of a G-quadruplex motif as a regulatory element of the TYMS gene. PPRHs have also the potential to correct point mutations in the DNA as shown in two collections of CHO cell lines bearing mutations in either the dhfr or aprt loci. Finally, based on the capability of PPRHs to form triplexes, they have been incorporated as probes in biosensors for the determination of the DNA methylation status of PAX-5 in cancer and the detection of mtLSU rRNA for the diagnosis of Pneumocystis jirovecii. Of note, PPRHs have high stability and do not present immunogenicity, hepatotoxicity or nephrotoxicity in vitro. Overall, PPRHs constitute a new economical biotechnological tool with multiple biomedical applications.

T cell receptor therapy against melanoma-Immunotherapy for the future?

Malignant melanoma has seen monumental changes in treatment options the last decade from the very poor results of dacarbazine treatment to the modern-day use of targeted therapies and immune checkpoint inhibitors. Melanoma has a high mutational burden making it more capable of evoking immune responses than many other tumours. Even when considering double immune checkpoint blockade with anti-CTLA-4 and anti-PD-1, we still have far to go in melanoma treatment as 50% of patients with metastatic disease do not respond to current treatment. Alternative immunotherapy should therefore be considered. Since melanoma has a high mutational burden, it is considered more immunogenic than many other tumours. T cell receptor (TCR) therapy could be a possible way forward, either alone or in combination, to improve the response rates of this deadly disease. Melanoma is one of the cancers where TCR therapy has been frequently applied. However, the number of antigens targeted remains fairly limited, although advanced personalized therapies aim at also targeting private mutations. In this review, we look at possible aspects of targeting TCR therapy towards melanoma and provide an implication of its use in the future.

Triggered Immune Response Induced by Antigenic Epitopes Covalently Linked with Immunoadjuvant-Pulsed Dendritic Cells as a Promising Cancer Vaccine

The success of peptide-based dendritic cell (DC) cancer vaccines mainly depends on the utilized peptides and selection of an appropriate adjuvant. Herein, we aimed to evoke a broad immune response against multiple epitopes concurrently in the presence of immunoadjuvant. Three synthetic HLA-A∗0201-restricted peptides were separately linked with HMGB1-derived peptide (SAFFLFCSE, denoted as HB_100-108) as immunoadjuvant via double arginine (RR) linker and loaded onto human monocyte-derived DCs. Peptide uptake was detected by immunofluorescence microscopy and flow cytometry. The maturation and activation status of pulsed DCs were monitored by detection of the expression of specific markers and released cytokines. The ability of peptide-pulsed DCs to activate allogeneic T cells has been assessed by a degranulation assay and detection of secreted cytokines. The lytic activity of effector T cells against cancer cells in vitro was analyzed by a lactate dehydrogenase (LDH) assay. Results revealed that DCs efficiently take up peptides+HB_100-108 and expressed higher levels of surface markers (HLA-ABC, HLA-DR, CD80, CD86, CD83, CD40, and CCR7) and proinflammatory cytokines (IL-6, IFN-γ, TNF-α, and IL-12) than control DCs, free peptide-pulsed DCs, and free HB_100-108-pulsed DC groups. Moreover, peptides+HB_100-108/pulsed DCs were capable of activating allogeneic T cells and enhance their lytic activity against a pancreatic cancer cell line (PANC-1) in vitro. These findings suggest that antigenic peptides covalently linked with HB_100-108/pulsed DCs could be a promising strategy to improve the current DC-based cancer vaccines.

New Aspects of Ultrasound-Mediated Targeted Delivery and Therapy for Cancer

Ultrasound-mediated targeted delivery (UMTD), a novel delivery modality of therapeutic materials based on ultrasound, shows great potential in biomedical applications. By coupling ultrasound contrast agents with therapeutic materials, UMTD combines the advantages of ultrasound imaging and carrier, which benefit deep tissue penetration and high concentration aggregation. In this paper we introduced recent advances in ultrasound contrast agents and applications in tumor therapy. Ultrasound contrast agents were categorized by their functions, mainly including thermosensitive, pH-sensitive and photosensitive ultrasound contrast agents. The various applications of UMTD in tumor treatment were summarized as follows: drug therapy, transfection of anti-oncogene, RNA interference, vaccine immunotherapy, monoclonal antibody immunotherapy, adoptive cellular immunotherapy, cytokine immunotherapy, and so on. In the end, we elaborated on the current challenges and provided perspectives of UMTD for clinical applications.

The survivin molecule as a double-edged sword in cellular physiologic and pathologic conditions and its role as a potential biomarker and therapeutic target in cancer

Survivin is a member of the family of apoptosis inhibitory proteins with increased expression level in most cancerous tissues. Evidence shows that survivin plays regulatory roles in proliferation or survival of normal adult cells, principally vascular endothelial cells, T lymphocytes, primitive hematopoietic cells, and polymorphonuclear neutrophils. Survivin antiapoptotic role is, directly and indirectly, related to caspase proteins and shows its role in cell division through the chromosomal passenger complex. Survivin contains many genetic polymorphisms that the role of some variations has been proven in several cancers. The -31G/C polymorphism is one of the most important survivin mutations which is located in the promoter region on a CDE/CHR motif. This polymorphism can upregulate the survivin messenger RNA. In addition, its allele C can increase the risk of cancers in 1.27-fold than allele G. Considering the fundamental role of survivin in different cancers, this protein could be considered as a new therapeutic target in cancer treatment. For this purpose, various strategies have been designed including the prevention of survivin expression through inhibition of mRNA translation using antagonistic molecules, inhibition of survivin gene function through small inhibitory molecules, gene therapy, and immunotherapy. In this study, we describe the structure, played roles in physiological and pathological states and genetic polymorphisms of survivin. Finally, the role of survivin as a potential target in cancer therapy given challenges ahead has been discussed.

Role of Survivin and p53 Expression in Response of Primary Culture of Ovarian Cancer Cells to Treatment With Chemotherapeutic Agents

BACKGROUND

Ovarian cancer is associated with a high relapse rate and is the fifth leading cause of cancer deaths in women. The genetic profile of a tumor is responsible for deciding response to chemotherapeutic agents. In this study, we investigate the relation between survivin and p53 expression and response to chemotherapeutic agents of primary cultures of ovarian cancer cells established from ascitic fluid.

MATERIALS AND METHOD

Ascitic fluid and Dulbecco's modified Eagle medium was mixed in equal proportion in culture flasks and incubated to establish primary culture. The cells were treated with different combinations of carboplatin and paclitaxel with and without survivin small interfering RNA transfection. Cell survival was estimated by MTT assay. Survivin and p53 expression was quantified by real-time polymerase chain reaction.

RESULTS

Out of 19 ascitic fluid samples, 13 primary cultures of ovarian cancer cells were established. The half maximal inhibitory concentration doses of carboplatin (≥70 μg/mL) and paclitaxel (≥18 μg/mL) were high for 10/13 and 5/13 patients, respectively. Survivin messenger RNA expression was significantly downregulated on treatment with carboplatin (100 μg/mL), paclitaxel (12.5 μg/mL), and a combination of carboplatin (50 μg/mL) and paclitaxel (6.25 μg/mL). Only paclitaxel-treated ovarian cancer cells showed decrease in expression of p53. Survivin small interfering RNA increased sensitivity of the primary cultures to chemotherapeutic agents.

CONCLUSIONS

The present study highlights the fact that establishing primary cultures from ascitic fluid may help to develop personalized treatment regime for individual patients based on their molecular profile. Our study also shows that supplementing taxols drugs with survivin inhibitors may prove to be beneficial in the treatment of ovarian cancer patients.

Advances in the Understanding of Skin Cancer: Ultraviolet Radiation, Mutations, and Antisense Oligonucleotides as Anticancer Drugs

Skin cancer has always been and remains the leader among all tumors in terms of occurrence. One of the main factors responsible for skin cancer, natural and artificial UV radiation, causes the mutations that transform healthy cells into cancer cells. These mutations inactivate apoptosis, an event required to avoid the malignant transformation of healthy cells. Among these deadliest of cancers, melanoma and its ‘younger sister’, Merkel cell carcinoma, are the most lethal. The heavy toll of skin cancers stems from their rapid progression and the fact that they metastasize easily. Added to this is the difficulty in determining reliable margins when excising tumors and the lack of effective chemotherapy. Possibly the biggest problem posed by skin cancer is reliably detecting the extent to which cancer cells have spread throughout the body. The initial tumor is visible and can be removed, whereas metastases are invisible to the naked eye and much harder to eliminate. In our opinion, antisense oligonucleotides, which can be used in the form of targeted ointments, provide real hope as a treatment that will eliminate cancer cells near the tumor focus both before and after surgery.

Co-Delivery of Eugenol and Dacarbazine by Hyaluronic Acid-Coated Liposomes for Targeted Inhibition of Survivin in Treatment of Resistant Metastatic Melanoma

While melanoma remains a challenge for oncologists, possibilities are being continuously explored to fight resistant metastatic melanoma more effectively. Eugenol is reported to inhibit survivin protein in breast cancer cells. Survivin is also overexpressed by melanoma cells, and is known to impart resistance to them against chemotherapy-induced apoptosis. To be able to fight resistant melanoma, we formulated hyaluronic acid (HA)-coated liposomes loaded with an effective combination of anti-melanoma agents (Dacarbazine and Eugenol), using a solvent injection method. Quality-by-Design (QbD) was applied to optimize and obtain a final formulation with the desired quality attributes, and within an acceptable size range. The optimized formulation was then subjected to performance analysis in cell lines. Coated-Dacarbazine Eugenol Liposomes were found to possess 95.08% cytotoxicity at a dacarbazine concentration of 0.5 µg/mL, while Dacarbazine Solution showed only 10.20% cytotoxicity at the same concentration. The number of late apoptotic cells was also found to be much higher (45.16% vs. 8.43%). Furthermore, migration assay and proliferation study also revealed significantly higher inhibition of cell migration and proliferation by Coated-Dacarbazine Eugenol Liposomes, signifying its potential against metastasis. Thus, surface-functionalized dacarbazine- and eugenol-loaded liposomes hold great promise against resistant and aggressive metastatic melanoma, with much less unwanted cytotoxicity and reduced doses of the chemotherapeutic agent.

Tissue-specific DNA methylation loss during ageing and carcinogenesis is linked to chromosome structure, replication timing and cell division rates

DNA methylation is an epigenetic mechanism known to affect gene expression and aberrant DNA methylation patterns have been described in cancer. However, only a small fraction of differential methylation events target genes with a defined role in cancer, raising the question of how aberrant DNA methylation contributes to carcinogenesis. As recently a link has been suggested between methylation patterns arising in ageing and those arising in cancer, we asked which aberrations are unique to cancer and which are the product of normal ageing processes. We therefore compared the methylation patterns between ageing and cancer in multiple tissues. We observed that hypermethylation preferentially occurs in regulatory elements, while hypomethylation is associated with structural features of the chromatin. Specifically, we observed consistent hypomethylation of late-replicating, lamina-associated domains. The extent of hypomethylation was stronger in cancer, but in both ageing and cancer it was proportional to the replication timing of the region and the cell division rate of the tissue. Moreover, cancer patients who displayed more hypomethylation in late-replicating, lamina-associated domains had higher expression of cell division genes. These findings suggest that different cell division rates contribute to tissue- and cancer type-specific DNA methylation profiles.

Inhibitors of apoptosis: clinical implications in cancer

Inhibitor of apoptosis (IAP) family comprises a group of endogenous proteins that function as main regulators of caspase activity and cell death. They are considered the main culprits in evasion of apoptosis, which is a fundamental hallmark of carcinogenesis. Overexpression of IAP proteins has been documented in various solid and hematological malignancies, rendering them resistant to standard chemotherapeutics and radiation therapy and conferring poor prognosis. This observation has urged their exploitation as therapeutic targets in cancer with promising pre-clinical outcomes. This review describes the structural and functional features of IAP proteins to elucidate the mechanism of their anti-apoptotic activity. We also provide an update on patterns of IAP expression in different tumors, their impact on treatment response and prognosis, as well as the emerging investigational drugs targeting them. This aims at shedding the light on the advances in IAP targeting achieved to date, and encourage further development of clinically applicable therapeutic approaches.

Aspirin Suppresses PGE2 and Activates AMP Kinase to Inhibit Melanoma Cell Motility, Pigmentation, and Selective Tumor Growth In Vivo

There are conflicting epidemiologic data on whether chronic aspirin (ASA) use may reduce melanoma risk in humans. Potential anticancer effects of ASA may be mediated by its ability to suppress prostaglandin E₂ (PGE₂) production and activate 5'-adenosine monophosphate-activated protein kinase (AMPK). We investigated the inhibitory effects of ASA in a panel of melanoma and transformed melanocyte cell lines, and on tumor growth in a preclinical model. ASA and the COX-2 inhibitor celecoxib did not affect melanoma cell viability, but significantly reduced colony formation, cell motility, and pigmentation (melanin production) in vitro at concentrations of 1 mmol/L and 20 μmol/L, respectively. ASA-mediated inhibition of cell migration and pigmentation was rescued by exogenous PGE₂ or Compound C, which inhibits AMPK activation. Levels of tyrosinase, MITF, and p-ERK were unaffected by ASA exposure. Following a single oral dose of 0.4 mg ASA to NOD/SCID mice, salicylate was detected in plasma and skin at 4 hours and PGE₂ levels were reduced up to 24 hours. Some human melanoma tumors xenografted into NOD/SCID mice were sensitive to chronic daily ASA administration, exhibiting reduced growth and proliferation. ASA-treated mice bearing sensitive and resistant tumors exhibited both decreased PGE₂ in plasma and tumors and increased phosphorylated AMPK in tumors. We conclude that ASA inhibits colony formation, cell motility, and pigmentation through suppression of PGE₂ and activation of AMPK and reduces growth of some melanoma tumors in vivo This preclinical model could be used for further tumor and biomarker studies to support future melanoma chemoprevention trials in humans. Cancer Prev Res; 11(10); 629-42. ©2018 AACR.

Real-Time Imaging of Retinal Ganglion Cell Apoptosis

Monitoring real-time apoptosis in-vivo is an unmet need of neurodegeneration science, both in clinical and research settings. For patients, earlier diagnosis before the onset of symptoms provides a window of time in which to instigate treatment. For researchers, being able to objectively monitor the rates of underlying degenerative processes at a cellular level provides a biomarker with which to test novel therapeutics. The DARC (Detection of Apoptosing Retinal Cells) project has developed a minimally invasive method using fluorescent annexin A5 to detect rates of apoptosis in retinal ganglion cells, the key pathological process in glaucoma. Numerous animal studies have used DARC to show efficacy of novel, pressure-independent treatment strategies in models of glaucoma and other conditions where retinal apoptosis is reported, including Alzheimer’s disease. This may forge exciting new links in the clinical science of treating both cognitive and visual decline. Human trials are now underway, successfully demonstrating the safety and efficacy of the technique to differentiate patients with progressive neurodegeneration from healthy individuals. We review the current perspectives on retinal ganglion cell apoptosis, the way in which this can be imaged, and the exciting advantages that these future methods hold in store.

Annexins in Glaucoma

Glaucoma is one of the leading causes of irreversible visual loss, which has been estimated to affect 3.5% of those over 40 years old and projected to affect a total of 112 million people by 2040. Such a dramatic increase in affected patients demonstrates the need for continual improvement in the way we diagnose and treat this condition. Annexin A5 is a 36 kDa protein that is ubiquitously expressed in humans and is studied as an indicator of apoptosis in several fields. This molecule has a high calcium-dependent affinity for phosphatidylserine, a cell membrane phospholipid externalized to the outer cell membrane in early apoptosis. The DARC (Detection of Apoptosing Retinal Cells) project uses fluorescently-labelled annexin A5 to assess glaucomatous degeneration, the inherent process of which is the apoptosis of retinal ganglion cells. Furthermore, this project has conducted investigation of the retinal apoptosis in the neurodegenerative conditions of the eye and brain. In this present study, we summarized the use of annexin A5 as a marker of apoptosis in the eye. We also relayed the progress of the DARC project, developing real-time imaging of retinal ganglion cell apoptosis in vivo from the experimental models of disease and identifying mechanisms underlying neurodegeneration and its treatments, which has been applied to the first human clinical trials. DARC has potential as a biomarker in neurodegeneration, especially in the research of novel treatments, and could be a useful tool for the diagnosis and monitoring of glaucoma.

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.

Potential Benefits of Annona muricata in Combating Cancer: A Review

The incidence of cancer is increasing each year, which generates concerns regarding the efficacy of the current treatment options. This has caused patients to seek alternatives to complement or to replace surgery, chemotherapy and radiotherapy. Annona muricata and other plants have been shown to have promising compounds that can be utilised in the treatment of cancer. Native to the tropical and subtropical parts of the world, A. muricata plant extracts contain compounds that are particularly effective against cancer cells. In light of increasing concerns regarding the limitations of cancer treatment in hospitals, this review attempts to highlight the benefits of A. muricata and its potential to be integrated as one of the treatment options against cancer.

Intron-specific shRNA-mediated downregulation of survivin and promotion of apoptosis in HeLa cells

Overexpression of the survivin gene contributes to tumorigenesis; it has been recognized as an important target for cancer therapy. In the present study, survivin expression was suppressed using recombinant plasmid mediated short hairpin RNAs (shRNAs) that were constructed to target exonic or intronic sequences of the survivin gene. In addition, a negative control shRNA was constructed. HeLa cells were transfected with specific shRNA constructs and the blocking efficiency of each shRNA was assessed at the mRNA and protein levels; and the five shRNA constructs with higher blocking efficiency were selected. Cell apoptosis was assessed by flow cytometry (FCM) following Annexin V-fluorescein isothiocyanate/propidium iodide double staining. Hoechst staining was used to detect the morphological diversity of the nuclei in apoptotic cells. The results demonstrated that survivin expression was effectively reduced by the transfection of shRNAs in HeLa cells. In addition, the apoptotic rates of the shRNA-treated groups were significantly increased compared with the negative control group according to the FCM results. The nuclei of HeLa cells exhibited apoptotic characteristics in the shRNA-treated groups as identified by Hoechst staining. Survivin-targeting shRNAs effectively downregulated the expression of the gene and markedly increased the apoptotic rate of HeLa cells. Data from the present study also indicated that the intron-specific shRNA demonstrate a high efficiency of inhibition of survivin expression and were able to induce cell apoptosis of HeLa cells through RNAi, potentially providing novel target sites for tumor therapy. In conclusion, the present study suggests that intron-specific blocking of survivin by RNAi may provide a tool for anticancer therapy.

Indoleamine 2,3-dioxygenase and survivin peptide vaccine combined with temozolomide in metastatic melanoma

BACKGROUND

Indoleamine 2,3-dioxygenase (IDO) and survivin have been identified as potential targets for cancer vaccination. In this phase II study a vaccine using the peptides Sur1M2 and IDO5 was combined with the chemotherapy temozolomide (TMZ) for treatment of metastatic melanoma patients. The aim was to simultaneously target several immune inhibiting mechanisms and the highly malignant cells expressing survivin.

METHODS

HLA-A2 positive patients with advanced malignant melanoma were treated biweekly with 150 mg/m² TMZ daily for 7 days followed by subcutaneous vaccination with 250 µg of each peptide in 500 µL Montanide solution at day 8. Granulocyte-macrophage colony-stimulating factor was used as an adjuvant and topical imiquimod was applied prior to vaccination. Treatment was continued until disease progression. Clinical response was evaluated by PET-CT and immunological outcome was assessed by ELISPOT and flow cytometry.

RESULTS

In total, 17 patients were treated with a clinical benefit rate of 18% including one patient with partial tumor regression. Immune analyses revealed a vaccine specific response in 8 (67%) of 12 patients tested, a significant decrease in the frequency of CD4+ T-cells during treatment, a tendency towards decreasing frequencies of naïve CD4+ and CD8+ T-cells, and increasing frequencies of memory CD4+ and CD8+ T-cells.

CONCLUSIONS

These results demonstrate that vaccine-induced immunity towards survivin and IDO-derived peptides can be achieved in combination with TMZ in patients mainly suffering from grade M1c melanoma including patients with brain metastases. A significant clinical activity could not be proven in this small study and a larger setup is needed to properly assess clinical efficacy.

The HGF/SF Mouse Model of UV-Induced Melanoma as an In Vivo Sensor for Metastasis-Regulating Gene

Cutaneous malignant melanoma is an aggressive and potentially lethal form of skin cancer, particularly in its advanced and therapy-resistant stages, and the need for novel therapeutics and prognostic tools is acute. Incidence of melanoma has steadily increased over the past few decades, with exposure to the genome-damaging effects of ultraviolet radiation (UVR) well-recognized as a primary cause. A number of genetically-engineered mouse models (GEMMs) have been created that exhibit high incidence of spontaneous and induced forms of melanoma, and a select subset recapitulates its progression to aggressive and metastatic forms. These GEMMs hold considerable promise for providing insights into advanced stages of melanoma, such as potential therapeutic targets and prognostic markers, and as in vivo systems for testing of novel therapies. In this review, we summarize how the HGF/SF transgenic mouse has been used to reveal metastasis-regulating activity of four different genes (CDK4^R24C, survivin and NME1/NME2) in the context of UV-induced melanoma. We also discuss how these models can potentially yield new strategies for clinical management of melanoma in its most aggressive forms.

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.

Preclinical development of HIvax: Human survivin highly immunogenic vaccines

Our previous work involved the development of a recombinant fowlpox virus encoding survivin (FP-surv) vaccine that was evaluated for efficacy in mesothelioma mouse models. Results showed that FP-surv vaccination generated significant immune responses, which led to delayed tumor growth and improved animal survival. We have extended those previous findings in the current study, which involves the pre-clinical development of an optimized version of FP-surv designed for human immunization (HIvax). Survivin-derived peptides for the most common haplotypes in the human population were identified and their immunogenicity confirmed in co-culture experiments using dendritic cells and T cells isolated from healthy donors. Peptides confirmed to induce CD8(+) and CD4(+) T cells activation in humans were then included in 2 transgenes optimized for presentation of processed peptides on MHC-I (HIvax1) and MHC-II (HIvax2). Fowlpox vectors expressing the HIvax transgenes were then generated and their efficacy was evaluated with subsequent co-culture experiments to measure interferon-γ and granzyme B secretion. In these experiments, both antigen specific CD4(+) and CD8(+) T cells were activated by HIvax vaccines with resultant cytotoxic activity against survivin-overexpressing mesothelioma cancer cells. These results provide a rationale for clinical testing of HIvax1 and HIvax2 vaccines in patients with survivin-expressing cancers.

Development of replication-competent adenovirus for bladder cancer by controlling adenovirus E1a and E4 gene expression with the survivin promoter

Survivin is a member of the inhibitors of apoptosis protein family. Here, we examined survivin expression and confirmed abundant survivin expression in bladder cancer cells. This expression pattern indicated that the transcriptional regulatory elements that control survivin expression could be utilized to discriminate cancer from normal cells. We therefore generated a novel adenovirus termed Ad5/35E1apsurvivinE4 with the following characteristics: 1) E1A and E4 protein expression was dependent on survivin promoter activity; 2) the green fluorescence protein gene was inserted into the genome under the control of the CMV promoter; 3) most of the E3 sequences were deleted, but the construct was still capable of expressing the adenovirus death protein with potent cytotoxic effects; and 4) the fiber knob was from serotype 35 adenovirus. As expected from the abundant survivin expression observed in bladder cancer cells, Ad5/35E1apsurvivinE4 replicated better in cancer cells than in normal cells by a factor of 10⁶ to 10². Likewise, Ad5/35E1apsurvivinE4 exerted greater cytotoxic effects on all bladder cancer cell lines tested. Importantly, Ad5/35E1apsurvivinE4 inhibited the growth of Ku7-Luc orthotopic xenografts in nude mice. Taken together, Ad5/35E1apsurvivinE4 indicates that the survivin promoter may be utilized for the development of a replication-competent adenovirus to target bladder cancers.

Mitotic slippage and expression of survivin are linked to differential sensitivity of human cancer cell-lines to the Kinesin-5 inhibitor monastrol

The mitotic Kinesin-5 motor proteins crosslink and slide apart antiparallel spindle microtubules, thus performing essential functions in mitotic spindle dynamics. Specific inhibition of their function by monastrol-like small molecules has been examined in clinical trials as anticancer treatment, with only partial success. Thus, strategies that improve the efficiency of monastrol-like anticancer drugs are required. In the current study, we examined the link between sensitivity to monastrol and occurrence of mitotic slippage in several human cell-lines. We found that the rank of sensitivity to monastrol, from most sensitive to least sensitive, is: AGS > HepG2 > Lovo > Du145 ≥ HT29. We show correlation between the sensitivity of a particular cell-line to monastrol and the tendency of the same cell-line to undergo mitotic slippage. We also found that in the monastrol resistant HT29 cells, prolonged monastrol treatments increase mRNA and protein levels of the chromosomal passenger protein survivin. In contrast, survivin levels are not increased by this treatment in the monastrol-sensitive AGS cells. We further show that over-expression of survivin in the monastrol-sensitive AGS cells reduces mitotic slippage and increases resistance to monastrol. Finally, we show that during short exposure to monastrol, Si RNA silencing of survivin expression reduces cell viability in both AGS and HT29 cells. Our data suggest that the efficiency of anti-cancer treatment with specific kinesin-5 inhibitors may be improved by modulation of expression levels of survivin.

AC-93253 triggers the downregulation of melanoma progression markers and the inhibition of melanoma cell proliferation

A major challenge in anti-melanoma therapy is to develop treatments that are effective for advanced melanoma patients. Unfortunately, the currently used regimens are not efficient and have unsatisfactory effects on disease progression, thus increasing the pressure to develop new, profitable drugs and to identify new molecular targets. Here, we show for the first time that AC-93253, a SIRT2 inhibitor, exerts a negative effect on the expression of a set of genes involved in the progression and chemoresistance (e.g., oncogenes, apoptosis-related genes, ABC transporter genes, and cell cycle control genes) of melanoma cells. Furthermore, melanoma cells exposed to AC-93253 and doxorubicin displayed altered biological responses, including apoptosis and proliferation, compared to cells exposed to single treatments. Taken together, we conclude that the usage of AC-93253 in combined therapy could be a promising strategy for melanoma patients.

Survivin and PSMA Loaded Dendritic Cell Vaccine for the Treatment of Prostate Cancer

Dendritic cell (DC)-based vaccines are a promising therapeutic modality for cancer. Results from recent trials and approval of the first DC vaccine by the U.S. Food and Drugs Administration for prostate cancer have paved the way for DC-based vaccines. A total of 21 hormone refractory prostate cancer (HRPC) patients with a life expectancy >3 months were randomised into two groups. DC loaded with recombinant Prostate Specific Membrane Antigen (rPSMA) and recombinant Survivin (rSurvivin) peptides was administered as an subcutaneous (s.c.) injection (5×10(6) cells). Docetaxel (75 mg/m(2) intravenous (i.v.)) and prednisone (5 mg, bis in die (b.i.d.)) served as control. Clinical and immunological responses were evaluated. Primary endpoints were safety and feasibility; secondary endpoint was overall survival. Responses were evaluated on day 15, day 30, day 60, and day 90. DC vaccination was well tolerated with no signs of grade 2 toxicity. DC vaccination induced delayed-type hypersensitivity reactivity and an immune response in all patients. Objective Response Rate (ORR) by Response Evaluation Criteria in Solid Tumours (RECIST) was 72.7% (8/11) versus 45.4 (5/11) in the docetaxel arm and immune related response criteria (irRC) was 54.5% (6/11) compared with 27.2% (3/11) in the control arm. The DC arm showed stable disease (SD) in 6 patients, progressive disease (PD) in 3 patients, and partial remission (PR) in two patients compared to SD in 5 patients, PD in 6 patients, and PR in none in the docetaxel arm. There was a cellular response, disease stabilization, no adverse events, and partial remission with the rPSMA and rSurvivin primed DC vaccine.

Recent Advances on Small-Molecule Survivin Inhibitors

Survivin, a member of the inhibitor of apoptosisproteins family, is highly expressed in most human neoplasms, but its expression is very low or undetectable in terminally differentiated normal tissues. Survivin has been shown to inhibit cancer cell apoptosis and promote cell proliferation. The overexpression of survivin closely correlates with tumor progression and drug resistance. Because of its key role in tumor formation and maintenance, survivin is considered as an ideal target for anticancer treatment. However, the development of small-molecule survivin inhibitors has been challenging due to the requirement to disrupt the protein-protein interactions. Currently only a limited number of survivin inhibitors have been developed in recent years, and most of these inhibitors reduce survivin levels by interacting with other biomolecules instead of directly interacting with survivin protein. Despite these challenges, developing potent and selective small-molecule survivin inhibitors will be important in both basic science to better understand survivin biology and in translational research to develop potentially more effective, broad-spectrum anticancer agents. In this review, the functions of survivin and its role in cancer are summarized. Recent developments, challenges, and future direction of small-molecule survivin inhibitors are also discussed in detail.

A phase 2, multicenter, open-label study of sepantronium bromide (YM155) plus docetaxel in patients with stage III (unresectable) or stage IV melanoma

Survivin is a microtubule-associated protein believed to be involved in preserving cell viability and regulating tumor cell mitosis, and it is overexpressed in many primary tumor types, including melanoma. YM155 is a first-in-class survivin suppressant. The purpose of this Phase 2 study was to evaluate the 6-month progression-free survival (PFS) rate in patients with unresectable Stage III or IV melanoma receiving a combination of YM155 plus docetaxel. The study had two parts: Part 1 established the dose of docetaxel that was tolerable in combination with YM155, and Part 2 evaluated the tolerable docetaxel dose (75 mg/m²) in combination with YM155 (5 mg/m² per day continuous infusion over 168 h every 3 weeks). The primary endpoint was 6-month PFS rate. Secondary endpoints were objective response rate (ORR), 1-year overall survival (OS) rate, time from first response to progression, clinical benefit rate (CBR), and safety. Sixty-four patients with metastatic melanoma were treated with docetaxel and YM155. Eight patients received an initial docetaxel dose of 100 mg/m² and 56 patients received 75 mg/m² of docetaxel. Six-month PFS rate per Independent Review Committee (IRC) was 34.8% (n = 64; 95% CI, 21.3–48.6%), and per Investigator was 31.3% (n = 64; 95% CI, 19.5–43.9%). The best ORR (complete response [CR] + partial response [PR]) per IRC was 12.5% (8/64). The stable disease (SD) rate was 51.6% (33/64), leading to a CBR (CR + PR + SD) of 64.1% (41/64). Estimated probability of 1-year survival was 56.3%. YM155 is a novel agent showing modest activity when combined with docetaxel for treating patients with melanoma. YM155 was generally well tolerated, but the predetermined primary efficacy endpoint (i.e., 6-month PFS rate ≥20%) was not achieved.

Theranostic properties of a survivin-directed molecular beacon in human melanoma cells

Survivin is an inhibitor of apoptosis overexpressed in different types of tumors and undetectable in most terminally differentiated normal tissues. In the current study, we sought to evaluate the in vitro theranostic properties of a molecular beacon-oligodeoxynucleotide (MB) that targets survivin mRNA. We used laser scanning confocal microscopy to study MB delivery in living cells and real-time PCR and western blot to assess selective survivin-targeting in human malignant melanoma cells. We further assess the pro-apoptotic effect of MB by measuring internucleosomal DNA fragmentation, dissipation of mitochondrial membrane potential (MMP) and changes in nuclear morphology. Transfection of MB into A375 and 501 Mel cells generated high signal intensity from the cytoplasm, while no signal was detected in the extracellular environment and in survivin-negative cells (i.e., human melanocytes and monocytes). MB time dependently decreased survivin mRNA and protein expression in melanoma cells with the maximum effect reached at 72 h. Treatment of melanoma cells with MB induced apoptosis by significant changes in MMP, accumulation of histone-complexed DNA fragments in the cytoplasm and nuclear condensation. MB also enhanced the pro-apoptotic effect of standard chemotherapeutic drugs tested at clinically relevant concentrations. The MB tested in the current study conjugates the ability of imaging with the pharmacological silencing activity against survivin mRNA in human melanoma cells and may represent an innovative approach for cancer diagnosis and treatment.

Targeting the intrinsic apoptosis pathway as a strategy for melanoma therapy

Melanoma drug resistance is often attributed to abrogation of the intrinsic apoptosis pathway. Targeting regulators of apoptosis is thus considered a promising approach to sensitizing melanomas to treatment. The development of small-molecule inhibitors that mimic natural antagonists of either antiapoptotic members of the BCL-2 family or the inhibitor of apoptosis proteins (IAPs), known as BH3- or SMAC-mimetics, respectively, are helping us to understand the mechanisms behind apoptotic resistance. Studies using BH3-mimetics indicate that the antiapoptotic BCL-2 protein MCL-1 and its antagonist NOXA are particularly important regulators of BCL-2 family signaling, while SMAC-mimetic studies show that both XIAP and the cIAPs must be targeted to effectively induce apoptosis of cancer cells. Although most solid tumors, including melanoma, are insensitive to these mimetic drugs as single agents, combinations with other therapeutics have yielded promising results, and tests combining them with BRAF-inhibitors, which have already revolutionized melanoma treatment, are a clear priority.

Immunologic response to the survivin-derived multi-epitope vaccine EMD640744 in patients with advanced solid tumors

PURPOSE

Survivin is a member of the inhibitor-of-apoptosis family. Essential for tumor cell survival and overexpressed in most cancers, survivin is a promising target for anti-cancer immunotherapy. Immunogenicity has been demonstrated in multiple cancers. Nonetheless, few clinical trials have demonstrated survivin-vaccine-induced immune responses.

EXPERIMENTAL DESIGN

This phase I trial was conducted to test whether vaccine EMD640744, a cocktail of five HLA class I-binding survivin peptides in Montanide(®) ISA 51 VG, promotes anti-survivin T-cell responses in patients with solid cancers. The primary objective was to compare immunologic efficacy of EMD640744 at doses of 30, 100, and 300 μg. Secondary objectives included safety, tolerability, and clinical efficacy.

RESULTS

In total, 49 patients who received ≥2 EMD640744 injections with available baseline- and ≥1 post-vaccination samples [immunologic-diagnostic (ID)-intention-to-treat] were analyzed by ELISpot- and peptide/MHC-multimer staining, revealing vaccine-activated peptide-specific T-cell responses in 31 patients (63 %). This cohort included the per study protocol relevant ID population for the primary objective, i.e., T-cell responses by ELISpot in 17 weeks following first vaccination, as well as subjects who discontinued the study before week 17 but showed responses to the treatment. No dose-dependent effects were observed. In the majority of patients (61 %), anti-survivin responses were detected only after vaccination, providing evidence for de novo induction. Best overall tumor response was stable disease (28 %). EMD640744 was well tolerated; local injection-site reactions constituted the most frequent adverse event.

CONCLUSIONS

Vaccination with EMD640744 elicited T-cell responses against survivin peptides in the majority of patients, demonstrating the immunologic efficacy of EMD640744.

Survivin as a preferential target for cancer therapy

Cancer is typically a consequence of imbalance between cell death and proliferation in a way favorable to cell proliferation and survival. Most conventional cancer therapies are based on targeting rapidly growing cancerous cells to block growth or enhance cell death, thereby, restoring the balance between these processes. In many instances, malignancies that develop resistance to current treatment modalities, such as chemotherapy, immunotherapy, and radiotherapy often present the greatest challenge in subsequent management of the patient. Studies have shown that under normal circumstances, cells utilize different death mechanisms, such as apoptosis (programmed cell death), autophagy, mitotic catastrophe, and necrosis to maintain homeostasis and physiological integrity of the organism, but these processes often appear to be altered in cancer. Thus, in recent years developing various strategies for administration of cytotoxic chemotherapeutics in combination with apoptosis-sensitizing reagents is receiving more emphasis. Here, we review the properties of the anti-apoptotic protein, survivin, a member of the inhibitor of apoptosis protein (IAP) family and the clinical feasibility and anti-cancer potential of drugs targeting this protein. We also discuss some key points and concerns that should be taken into consideration while developing drugs that target apoptotic proteins, such as survivin.

Mechanism of DNA damage responses induced by exposure to an oligonucleotide homologous to the telomere overhang in melanoma

T-oligo, an 11-base oligonucleotide homologous to the 3'-telomeric overhang, is a novel, potent therapeutic modality in melanoma and multiple other tumor types. T-oligo is proposed to function in a manner similar to experimental disruption of the telomere overhang and induces DNA damage responses including apoptosis, differentiation and senescence. However, important components involved in T-oligo induced responses are not defined, particularly the role of p53, TRF1 and TRF2 in mediating the T-oligo induced responses. In MU, PM-WK, and MM-MC melanoma cells, exposure to T-oligo upregulates p53 expression and phosphorylation, resulting in cellular differentiation and activation of a caspase-mediated apoptotic cascade. However, siRNA-mediated knockdown of p53 completely blocks T-oligo induced differentiation and significantly decreases apoptosis, suggesting that p53 is an important mediator of T-oligo induced responses. In addition, we characterized the roles of telomere binding proteins, TRF1, TRF2, and tankyrase-1, in T-oligo induced damage responses. We demonstrate that tankyrase-1 activity is required for initiation of T-oligo induced damage responses including p53 phosphorylation and reduction of cellular proliferation. These results highlight TRF1, TRF2, tankyrase-1 and p53 as important elements in T-oligo mediated responses and suggest new avenues for research into T-oligo's mechanism of action.

Vaccination: role in metastatic melanoma

Based on the poor impact on overall survival obtained by systemic chemotherapy in metastatic melanoma and the identification of many melanoma antigens recognized by T cells, in the last decade many efforts have been devoted to the development of active specific immunotherapy as a promising systemic treatment for this neoplastic disease. A number of Phase I-II clinical trials have been performed with different vaccination approaches that included whole tumor cells, antigen peptides, antigen-pulsed dendritic cells, recombinant viruses, plasmids or naked DNA, and heat-shock proteins. Despite some promising immunological and clinical results obtained in these studies, melanoma-specific vaccines have altogether failed to prove their efficacy in the few large Phase III randomized clinical trials performed. Nonetheless, the possibility of activating the human immune system to recognize and destroy tumor cells remains a challenging investigative field, considering that the new knowledge of the intricate cellular and molecular mechanisms that regulate the immune function and tumor-host interactions may allow the development of new clinically relevant melanoma vaccination strategies.

Polypurine reverse Hoogsteen hairpins as a gene therapy tool against survivin in human prostate cancer PC3 cells in vitro and in vivo

As a new approach for gene therapy, we recently developed a new type of molecule called polypurine reverse Hoogsteen hairpins (PPRHs). We decided to explore the in vitro and in vivo effect of PPRHs in cancer choosing survivin as a target since it is involved in apoptosis, mitosis and angiogenesis, and overexpressed in different tumors. We designed four PPRHs against the survivin gene, one of them directed against the template strand and three against different regions of the coding strand. These PPRHs were tested in PC3 prostate cancer cells in an in vitro screening of cell viability and apoptosis. PPRHs against the promoter sequence were the most effective and caused a decrease in survivin mRNA and protein levels. We confirmed the binding between the selected PPRHs and their target sequences in the survivin gene. In addition we determined that both the template- and the coding-PPRH targeting the survivin promoter were interfering with the binding of transcription factors Sp1 and GATA-3, respectively. Finally, we conducted two in vivo efficacy assays using the Coding-PPRH against the survivin promoter and performing two routes of administration, namely intratumoral and intravenous, in a subcutaneous xenograft tumor model of PC3 prostate cancer cells. The results showed that the chosen Coding-PPRH proved to be effective in decreasing tumor volume, and reduced the levels of survivin protein and the formation of blood vessels. These findings represent the preclinical proof of principle of PPRHs as a new silencing tool for cancer gene therapy.

Sticky siRNAs targeting survivin and cyclin B1 exert an antitumoral effect on melanoma subcutaneous xenografts and lung metastases

Background

Melanoma represents one of the most aggressive and therapeutically challenging malignancies as it often gives rise to metastases and develops resistance to classical chemotherapeutic agents. Although diverse therapies have been generated, no major improvement of the patient prognosis has been noticed. One promising alternative to the conventional therapeutic approaches currently available is the inactivation of proteins essential for survival and/or progression of melanomas by means of RNA interference. Survivin and cyclin B1, both involved in cell survival and proliferation and frequently deregulated in human cancers, are good candidate target genes for siRNA mediated therapeutics.

Methods

We used our newly developed sticky siRNA-based technology delivered with linear polyethyleneimine (PEI) to inhibit the expression of survivin and cyclin B1 both in vitro and in vivo, and addressed the effect of this inhibition on B16-F10 murine melanoma tumor development.

Results

We confirm that survivin and cyclin B1 downregulation through a RNA interference mechanism induces a blockage of the cell cycle as well as impaired proliferation of B16-F10 cells in vitro. Most importantly, PEI-mediated systemic delivery of sticky siRNAs against survivin and cyclin B1 efficiently blocks growth of established subcutaneaous B16-F10 tumors as well as formation and dissemination of melanoma lung metastases. In addition, we highlight that inhibition of survivin expression increases the effect of doxorubicin on lung B16-F10 metastasis growth inhibition.

Conclusion

PEI-mediated delivery of sticky siRNAs targeting genes involved in tumor progression such as survivin and cyclin B1, either alone or in combination with chemotherapeutic drugs, represents a promising strategy for melanoma treatment.

Prospective multicenter randomized intermediate biomarker study of oral contraceptive versus depo-provera for prevention of endometrial cancer in women with Lynch syndrome

Women with Lynch syndrome have a 40% to 60% lifetime risk for developing endometrial cancer, a cancer associated with estrogen imbalance. The molecular basis for endometrial-specific tumorigenesis is unclear. Progestins inhibit estrogen-driven proliferation, and epidemiologic studies have shown that progestin-containing oral contraceptives (OCP) reduce the risk of endometrial cancer by 50% in women at general population risk. It is unknown whether they are effective in women with Lynch syndrome. Asymptomatic women ages 25 to 50 with Lynch syndrome were randomized to receive the progestin compounds Depo-Provera (depo-MPA) or OCP for three months. An endometrial biopsy and transvaginal ultrasound were conducted before and after treatment. Endometrial proliferation was evaluated as the primary endpoint. Histology and a panel of surrogate endpoint biomarkers were evaluated for each endometrial biopsy as secondary endpoints. A total of 51 women were enrolled, and 46 completed treatment. Two of the 51 women had complex hyperplasia with atypia at the baseline endometrial biopsy and were excluded from the study. Overall, both depo-MPA and OCP induced a dramatic decrease in endometrial epithelial proliferation and microscopic changes in the endometrium characteristic of progestin action. Transvaginal ultrasound measurement of endometrial stripe was not a useful measure of endometrial response or baseline hyperplasia. These results show that women with Lynch syndrome do show an endometrial response to short-term exogenous progestins, suggesting that OCP and depo-MPA may be reasonable chemopreventive agents in this high-risk patient population.

Anti-apoptotic proteins on guard of melanoma cell survival

Apoptosis plays a pivotal role in sustaining proper tissue development and homeostasis. Evading apoptosis by cancer cells is a part of their adaption to microenvironment and therapies. Cellular integrity is predominantly maintained by pro-survival members of Bcl-2 family and IAPs. Melanoma cells are characterized by a labile and stage-dependent phenotype. Pro-survival molecules can protect melanoma cells from apoptosis and mediate other processes, thus enhancing aggressive phenotype. The essential role of Bcl-2, Mcl-1, Bcl-X(L), livin, survivin and XIAP was implicated for melanoma, often in a tumor stage-dependent fashion. In this review, the current knowledge of pro-survival machinery in melanoma is discussed.