Apoptosis In Neoplastic Cells Research Articles

Development of Chemotherapy with Cell-Cycle Inhibitors for Adult and Pediatric Cancer Therapy.

Preclinical and clinical development of agents that inhibit cell-cycle progression have brought an understanding of the feasibility of targeting various cell-cycle regulators in patients with cancer. Small molecule inhibitors targeting key proteins that participate in cell-cycle progression including the cyclin-dependent kinases and checkpoint kinases induce cell-cycle arrest and apoptosis in neoplastic cells. Early phase I studies demonstrate targeted inhibitors can be administered safely in adult and pediatric cancer patients, but these agents generally show limited clinical benefits as single agents. In this review, we discuss biological mechanisms that support dual combination strategies of cell-cycle inhibition with chemotherapeutic agents that are anticipated to achieve rationally targeted therapies for cancer patients. The rationale for evaluating these combination strategies is that DNA damage renders tumors highly responsive to irreversible cell-cycle arrest therapy. This approach is predicted to generate less intensive therapies and to maximize the efficacy of individual agents against solid tumors and hematologic malignancies. Cancer Res; 78(2); 320-5. ©2018 AACR.

New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection.

Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the ‘hallmarks of cancer’ in glioblastoma multiforme.Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (Treg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme.

Tumor vascular infarction: prospects and challenges.

Induction of thrombosis in tumor vasculature represents an appealing strategy for combating cancer. Formation of fibrin clots may be sufficient to occlude the blood vessels that feed tumor cells, contributing to massive ischemia, vascular infarction, and the subsequent necrosis and apoptosis of neoplastic cells. This approach called as tumor vascular infarction was pioneered by Huang et al. (Science 275:547-550, 1997). Since then, different vascular targeting moieties were linked to a truncated form of human tissue factor (tTF), to generate coaguligands with selective thrombotic activities on tumor neovasculature. In contrast to the wide clinical application of angiogenesis inhibitors and tumor vascular disrupting agents, tTF-NGR is the only example of clinically tested coaguligands. Notably, among these three tumor vascular targeting approaches, tumor vascular infarction is the only modality manifesting long-term curative potential in mice. Translation of this worthy approach has been limited, as induction of thrombosis by TF fusion proteins is leaky. In this review, we describe the clinical significance of tumor vascular infarction, highlight its advantages and disadvantages, and propose a novel strategy for expediting its translation to clinical settings.

Role of local ablative techniques (Radiofrequency ablation and Irreversible Electroporation) in the treatment of pancreatic cancer.

Thanks to continuous research and investment in technology, the ablation of tumors has become common. Through the application of different types of energy is possible to induce cellular injury of the neoplastic tissue, leading to cellular death. Radiofrequency ablation (RFA) and irreversible electroporation (IRE) represent the most applied ablative techniques on pancreatic cancer. RFA and IRE, causing necrosis and apoptosis of neoplastic cells, are able to destroy neoplastic tissue, to drastically modify the neoplastic microenvironment and, possibly, to stimulate both directly and indirectly the anti-tumor immune system. This article provides part of our experience with the application of RFA and IRE on pancreatic adenocarcinoma (PDAC).

Abstract 181: Constitutive IRAK1/4 kinase activation contributes to NF-kB activity and chemoresistance in pancreatic cancer

Abstract Constitutive activation of the NF-κb transcription factor is a major molecular mechanism that contributes to the aggressive behavior and treatment resistance of pancreatic cancer. Understanding the molecular mechanisms that activate NF-κB will provide novel therapeutic opportunities to improve the dismal outcome of pancreatic cancer patients. In the present study, we showed that the Interleukin-1 Receptor-Associated Kinases 1 and 4 (IRAK1 and IRAK4) are constitutively activated in a majority of pancreatic cancer cell lines and patients samples, and are major drivers of NF-κB activity. Notably, we found that constitutive phosphorylation of IRAK4 is associated with poor patient prognosis. Suppression of IRAK1 and IRAK4 with small molecule inhibitor or RNA-interference in pancreatic cancer cells significantly reduces NF-κB activity, three-dimensional growth, invasiveness, production of inflammatory, and augment their sensitivity to chemotherapeutic agents in vitro. Notably, we showed that the NF-κB activity of pancreatic cancer cell with IRAK4 ablated using CRISPR technology can be restored with wild-type, but not kinase-dead IRAK4 mutant, supporting development of IRAK4 inhibitor as a novel therapeutic agent in pancreatic cancer. Silencing of IRAK1 or IRAK4, and more potently both, significantly abrogated the tumorigenic potential of human and murine pancreatic cancer cells as xenograft in mice. Lastly, we showed that IRAK1/4 inhibitor augments the therapeutic effect of gemcitabine in tumor-bearing mice by suppressing proliferation and increasing apoptosis of neoplastic cells, and reducing stromal fibrosis. Together, our data established IRAK4 kinase inhibitors as a promising novel class of targeted agent in pancreatic cancer. Citation Format: Daoxiang Zhang, Lin Li, Hongmei Jiang, Jinsheng Yu, Brett Knolhoff, Richard Head, Albert C. Lockhart, David G. DeNardo, Andrea Wang-Gillam, Marianna B. Ruzinova, Kian-Huat Lim. Constitutive IRAK1/4 kinase activation contributes to NF-kB activity and chemoresistance in pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 181.

Abstract 4058: DNA damage and tumour burden in mouse colon is increased in response to carcinogen exposure after induction of chronic inflammation - a more disease relevant model of colitis-associated colorectal cancer

Abstract Chronic inflammation (CI) such as inflammatory bowel disease increases the risk of developing colorectal cancer (CRC). Tumorigenesis is supported by inflammatory cytokines through increased cell proliferation and inhibiting apoptosis of neoplastic cells. The classic mouse model of colitis-associated CRC (CA-CRC) requires treatment with a mutagen (azoxymethane, AOM) followed by induction of inflammation through ingestion of a luminal irritant (dextran sulfate sodium, DSS). AOM is metabolized by colonic epithelium causing DNA damage through formation of mutagenic DNA adducts. Although the AOM + DSS model of CA-CRC is a valuable research model, it “reverses” events that take place in humans where CI typically precedes CRC. We hypothesise that CI sensitises colonic epithelium to DNA damage and predisposes the epithelium to neoplastic transformation. In order to investigate this we reversed the AOM + DSS model to more accurately represent the disease process in humans. Using two experimental approaches we treated wildtype (WT) mice with AOM alone or with DSS then AOM and collected colonic tissue after 6 and 48 hours (short-term) or colonic tumours (long-term). Tumour number and size were quantified. Immunohistochemistry was used to analyse DNA damage, apoptosis, and proliferation. Formation of the DNA adduct O6MeG was measured by a modified method of HPLC, and qPCR was used to analyse expression of DNA damage signalling pathway components. Compared with an AOM challenge alone, prior CI induction by DSS treatment increased DNA damage, reduced apoptosis, and increased tumour number and tumour size. This data reveals how prior CI modulates the colonic epithelial response to mutagen exposure in the short-term and how it promotes tumour formation in the long-term. In addition, this data demonstrates that the “reverse” model of CA-CRC can be successfully used as a more appropriate experimental framework to better understand the molecular mechanisms underpinning CA-CRC and will allow us to further investigate the relationship between prior CI, DNA damage, and tumour development. Citation Format: Tamsin RM Lannagan, Mark T. Mano, Richard J. Head, Trevor Lockett, Matthias Ernst, Leah J. Cosgrove. DNA damage and tumour burden in mouse colon is increased in response to carcinogen exposure after induction of chronic inflammation - a more disease relevant model of colitis-associated colorectal cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4058.

Engineered adenovirus fiber shaft fusion homotrimer of soluble TRAIL with enhanced stability and antitumor activity.

Successful cancer therapies aim to induce selective apoptosis in neoplastic cells. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered an attractive anticancer agent due to its tumor cell-specific cytotoxicity. However, earlier studies with recombinant TRAIL revealed many shortcomings, including a short half-life, off-target toxicity and existence of TRAIL-resistant tumor cells. In this study, we developed a novel engineering strategy for recombinant soluble TRAIL by redesigning its structure with the adenovirus knobless fiber motif to form a stable homotrimer with improved antitumor activity. The result is a highly stable fiber-TRAIL fusion protein that could form homotrimers similar to natural TRAIL. The recombinant fusion TRAIL developed here displayed high specific activity in both cell-based assays in vitro and animal tests in vivo. This construct will serve as a foundation for a new generation of recombinant proteins suitable for use in preclinical and clinical studies and for effective combination therapies to overcome tumor resistance to TRAIL.

Ethanolic Extract of Bark from Salix aegyptiaca Ameliorates 1,2-dimethylhydrazine-induced Colon Carcinogenesis in Mice by Reducing Oxidative Stress

ABSTRACTWe have previously shown that ethanolic extract from bark (EEB) of Salix aegyptiaca (Musk Willow) can inhibit proliferation and motility and induce apoptosis in colon cancer cells. Tandem mass spectrometry revealed EEB to be rich in catechin, catechol, and salicin. The present study investigated the chemopreventive effect of HPLC-fingerprinted EEB on 1,2-dimethylhydrazine (DMH)-induced aberrant crypt foci (ACF) formation in mice. DMH (20 mg/kg body weight) was weekly injected subcutaneously to mice for the first 2 weeks. EEB (100 and 400 mg/kg body weight) was provided orally from the 7th to 14th week, after which colon tissues were evaluated histologically and biochemically. DMH treatment induced high number of ACF; EEB significantly reduced the number and multiplicity of ACF, along with a restoration in goblet cells and mucin accumulation. EEB supplementation improved the markers of inflammation (myeloperoxidase and neutrophil infiltration) and oxidative stress. More importantly, EEB amplified apoptosis of neoplastic cells in the colon mucosa of DMH-treated mice. It also lowered levels of markers for early transformation events such as EGFR, nuclear β-catenin, and COX-2 in colon cancer cell lines HT-29 and HCT-116. The innocuity of EEB (up to 1600 mg/kg) to mice reinforces its potential as a chemopreventive agent.

A Phase I Safety, Pharmacokinetic, and Pharmacodynamic Presurgical Trial of Vitamin E δ-tocotrienol in Patients with Pancreatic Ductal Neoplasia

BackgroundVitamin E δ-tocotrienol (VEDT), a natural vitamin E from plants, has shown anti-neoplastic and chemoprevention activity in preclinical models of pancreatic cancer. Here, we investigated VEDT in patients with pancreatic ductal neoplasia in a window-of-opportunity preoperative clinical trial to assess its safety, tolerability, pharmacokinetics, and apoptotic activity. MethodsPatients received oral VEDT at escalating doses (from 200 to 3200mg) daily for 13days before surgery and one dose on the day of surgery. Dose escalation followed a three-plus-three trial design. Our primary endpoints were safety, VEDT pharmacokinetics, and monitoring of VEDT-induced neoplastic cell apoptosis (ClinicalTrials.gov number NCT00985777). FindingsIn 25 treated patients, no dose-limiting toxicity was encountered; thus no maximum-tolerated dose was reached. One patient had a drug-related adverse event (diarrhea) at a 3200-mg daily dose level. The effective half-life of VEDT was ~4h. VEDT concentrations in plasma and exposure profiles were quite variable but reached levels that are bioactive in preclinical models. Biological activity, defined as significant induction of apoptosis in neoplastic cells as measured by increased cleaved caspase-3 levels, was seen in the majority of patients at the 400-mg to 1600-mg daily dose levels. InterpretationVEDT from 200 to 1600mg daily taken orally for 2weeks before pancreatic surgery was well tolerated, reached bioactive levels in blood, and significantly induced apoptosis in the neoplastic cells of patients with pancreatic ductal neoplasia. These promising results warrant further clinical investigation of VEDT for chemoprevention and/or therapy of pancreatic cancer.

Usp9x- and Noxa-mediated Mcl-1 downregulation contributes to pemetrexed-induced apoptosis in human non-small-cell lung cancer cells.

Pemetrexed, a folate antimetabolite, combined with cisplatin is used as a first-line therapy for malignant pleural mesothelioma (MPM) and locally advanced or metastatic non-small-cell lung cancer (NSCLC). Pemetrexed arrests cell cycle by inhibiting three enzymes in purine and pyrimidine synthesis that are necessary for DNA synthesis. Pemetrexed also promotes apoptosis in target cells, but little is known about its mechanism in cancer cells. We have previously shown that pemetrexed can result in endoplasmic reticulum (ER) stress, and it can lead to downstream apoptosis. In this study, we further elucidate this mechanism. Our data show that pemetrexed increases Noxa expression through activating transcription factor 4 (ATF4) and activating transcription factor 3 (ATF3) upregulation. Furthermore, pemetrexed induces apoptosis by activating the Noxa–Usp9x–Mcl-1 pathway. Inhibition of Noxa by small interfering RNA (siRNA) promotes Usp9x (ubiquitin-specific peptidase 9, X-linked) expression. Moreover, downregulation of the deubiquitinase Usp9x by pemetrexed results in downstream reduction of myeloid cell leukemia 1 (Mcl-1) expression. Mechanistically, Noxa upregulation likely reduces the availability of Usp9x to Mcl-1, thereby promoting its ubiquitination and degradation, leading to the apoptosis of neoplastic cells. Thus, our findings demonstrate that Noxa–Usp9x-Mcl–1 axis may contribute to pemetrexed-induced apoptosis in human lung cancer cells.

Clinical activity and safety of the dual pathway inhibitor rigosertib for higher risk myelodysplastic syndromes following DNA methyltransferase inhibitor therapy.

Rigosertib (ON 01910.Na) is an inhibitor of the phosphoinositide 3-kinase and polo-like kinase pathways that induces mitotic arrest and apoptosis in neoplastic cells, while sparing normal cells. Our purpose is to summarize the clinical activity and safety of intravenous (IV) rigosertib delivered by an external ambulatory infusion pump in patients with refractory anemia with excess blasts-1, -2, or, -t myelodysplastic syndromes (MDS) following prior treatment with DNA methyltransferase (DNMT) inhibitors. A total of 39 patients with MDS who fulfilled these criteria were enrolled in four phase 1-2 clinical trials of IV rigosertib. Thirty five (88%) had higher risk disease according to the Revised International Prognostic Scoring System. Median overall survival for this group of 39 patients was 35 weeks. Of 30 evaluable patients with follow-up bone marrow biopsies, 12 (40%) achieved complete (n = 5) or partial (n = 7) bone marrow blast responses. In addition, 15 patients achieved stabilization of bone marrow blasts. One patient with a complete bone marrow response also achieved a complete cytogenetic response. A second patient with stable bone marrow blasts achieved a partial cytogenetic response. Two of the responding patients and three patients with stable disease had hematological improvements. Rigosertib-induced bone marrow blast decreases and stability appeared to be predictive of prolonged survival. IV rigosertib had a favorable safety profile without significant myelosuppression. Most common drug-related toxicities included fatigue, diarrhea, nausea, dysuria, and hematuria. In summary, IV rigosertib is well tolerated and has clinical activity in patients with higher risk MDS following DNMT inhibitor treatment. A multinational pivotal phase 3 randomized clinical trial of rigosertib versus best supportive care for patients with MDS with excess blasts following prior treatment with DNMT inhibitors (ONTIME: ON 01910.Na Trial In Myelodysplastic SyndromE) has recently completed enrollment.

Differential activity of GSK-3 isoforms regulates NF-κB and TRAIL- or TNFα induced apoptosis in pancreatic cancer cells

While TRAIL is a promising anticancer agent due to its ability to selectively induce apoptosis in neoplastic cells, many tumors, including pancreatic ductal adenocarcinoma (PDA), display intrinsic resistance, highlighting the need for TRAIL-sensitizing agents. Here we report that TRAIL-induced apoptosis in PDA cell lines is enhanced by pharmacological inhibition of glycogen synthase kinase-3 (GSK-3) or by shRNA-mediated depletion of either GSK-3α or GSK-3β. In contrast, depletion of GSK-3β, but not GSK-3α, sensitized PDA cell lines to TNFα-induced cell death. Further experiments demonstrated that TNFα-stimulated IκBα phosphorylation and degradation as well as p65 nuclear translocation were normal in GSK-3β-deficient MEFs. Nonetheless, inhibition of GSK-3β function in MEFs or PDA cell lines impaired the expression of the NF-κB target genes Bcl-xL and cIAP2, but not IκBα. Significantly, the expression of Bcl-xL and cIAP2 could be reestablished by expression of GSK-3β targeted to the nucleus but not GSK-3β targeted to the cytoplasm, suggesting that GSK-3β regulates NF-κB function within the nucleus. Consistent with this notion, chromatin immunoprecipitation demonstrated that GSK-3 inhibition resulted in either decreased p65 binding to the promoter of BIR3, which encodes cIAP2, or increased p50 binding as well as recruitment of SIRT1 and HDAC3 to the promoter of BCL2L1, which encodes Bcl-xL. Importantly, depletion of Bcl-xL but not cIAP2, mimicked the sensitizing effect of GSK-3 inhibition on TRAIL-induced apoptosis, whereas Bcl-xL overexpression ameliorated the sensitization by GSK-3 inhibition. These results not only suggest that GSK-3β overexpression and nuclear localization contribute to TNFα and TRAIL resistance via anti-apoptotic NF-κB genes such as Bcl-xL, but also provide a rationale for further exploration of GSK-3 inhibitors combined with TRAIL for the treatment of PDA.

Antiproliferative and Proapoptotic Effects of the TrK-inhibitor GW441756 in Human Myosarcomas and Prostatic Carcinoma

Neurotrophins (NTs) and their receptors, TrKs and p75NTR, have been shown to regulate proliferation and apoptosis of neoplastic cells. Pharmacological TrK blockade is considered a valuable target in cancer therapy, and several TrK inhibitors are under investigation. However, only a few of them have reached the stage of clinical development. Myosarcomas are aggressive cancers, which secrete NGF and respond poorly to available chemotherapies. Our previous work has shown that these cancers, characterized by autocrine activation of TrKA by NGF, which promotes cancer growth and survival, are highly susceptible to TrK blockade, both in vitro and in vivo. The same pattern has also been described in prostatic carcinoma. The present report characterizes for the first time the anti-proliferative and pro-apoptotic effects of the oxindole TrK inhibitor GW441756, in a panel of human myosarcomas and prostatic adenocarcinoma cell lines. Furthermore, we provide novel evidence that, in myosarcomas, characterized by a high-TrK/low-p75NTR phenotype, GW441756 upregulates p75NTR receptor expression, leading to apoptosis via caspase-3 activation. Altogether, our data expand the knowledge of the anti-neoplastic and pro-apoptotic mechanisms of GW441756, and of TrK inhibitors in general, lending further support to the therapeutic potential of TrK blockade in clinical oncology.

Antiproliferative and Proapoptotic Effects of the TrK-inhibitor GW441756 in Human Myosarcomas and Prostatic Carcinoma

Neurotrophins (NTs) and their receptors, TrKs and p75NTR, have been shown to regulate proliferation and apoptosis of neoplastic cells. Pharmacological TrK blockade is considered a valuable target in cancer therapy, and several TrK inhibitors are under investigation. However, only a few of them have reached the stage of clinical development. Myosarcomas are aggressive cancers, which secrete NGF and respond poorly to available chemotherapies. Our previous work has shown that these cancers, characterized by autocrine activation of TrKA by NGF, which promotes cancer growth and survival, are highly susceptible to TrK blockade, both in vitro and in vivo. The same pattern has also been described in prostatic carcinoma. The present report characterizes for the first time the anti-proliferative and pro-apoptotic effects of the oxindole TrK inhibitor GW441756, in a panel of human myosarcomas and prostatic adenocarcinoma cell lines. Furthermore, we provide novel evidence that, in myosarcomas, characterized by a high-TrK/low-p75NTR phenotype, GW441756 upregulates p75NTR receptor expression, leading to apoptosis via caspase-3 activation. Altogether, our data expand the knowledge of the anti-neoplastic and pro-apoptotic mechanisms of GW441756, and of TrK inhibitors in general, lending further support to the therapeutic potential of TrK blockade in clinical oncology.

Vorinostat Induces Apoptosis and Differentiation in Myeloid Malignancies: Genetic and Molecular Mechanisms

BackgroundAberrant epigenetic patterns are central in the pathogenesis of haematopoietic diseases such as myelodysplastic syndromes (MDS) and acute myeloid leukaemia (AML). Vorinostat is a HDACi which has produced responses in these disorders. The purpose of this study was to address the functional effects of vorinostat in leukemic cell lines and primary AML and MDS myeloid cells and to dissect the genetic and molecular mechanisms by which it exerts its action.Methodology/Principal FindingsFunctional assays showed vorinostat promoted cell cycle arrest, inhibited growth, and induced apoptosis and differentiation of K562, HL60 and THP-1 and of CD33+ cells from AML and MDS patients. To explore the genetic mechanism for these effects, we quantified gene expression modulation by vorinostat in these cells. Vorinostat increased expression of genes down-regulated in MDS and/or AML (cFOS, COX2, IER3, p15, RAI3) and suppressed expression of genes over-expressed in these malignancies (AXL, c-MYC, Cyclin D1) and modulated cell cycle and apoptosis genes in a manner which would favor cell cycle arrest, differentiation, and apoptosis of neoplastic cells, consistent with the functional assays. Reporter assays showed transcriptional effect of vorinostat on some of these genes was mediated by proximal promoter elements in GC-rich regions. Vorinostat-modulated expression of some genes was potentiated by mithramycin A, a compound that interferes with SP1 binding to GC-rich DNA sequences, and siRNA-mediated SP1 reduction. ChIP assays revealed vorinostat inhibited DNA binding of SP1 to the proximal promoter regions of these genes. These results suggest vorinostat transcriptional action in some genes is regulated by proximal promoter GC-rich DNA sequences and by SP1.ConclusionThis study sheds light on the effects of vorinostat in AML and MDS and supports the implementation of clinical trials to explore the use of vorinostat in the treatment of these diseases.

A nanoformulation of siRNA and its role in cancer therapy: In vitro and in vivo evaluation

Overexpression of anti-apoptotic Bcl-2 is often observed in a wide variety of human cancers. It prevents the induction of apoptosis in neoplastic cells and contributes to resistance to chemotherapy. RNA interference has emerged as an efficient and selective technique for gene silencing. The potential to use small interfering RNA (siRNA) as a therapeutic agent for the treatment of cancer has elicited a great deal of interest. However, insufficient cellular uptake and poor stability have limited its therapeutic applications. The purpose of this study was to prepare chitosan nanoparticles via ionic gelation of chitosan by tripolyphosphate for effective delivery of siRNA to silence the anti-apoptotic Bcl-2 gene in neoplastic cells. Chitosan nanoparticles loaded with siRNA were in the size range 190 to 340 nm with a polydispersive index ranging from 0.04 to 0.2. They were able to completely bind with siRNA, provide protection against nuclease degradation, and enhance the transfection. Cell culture studies revealed that nanoparticles with entrapped siRNA could efficiently silence the antiapoptotic Bcl-2 gene. Studies on Swiss albino mice showed that siRNA could be effectively delivered through nanoparticles. There was significant decrease in the tumor volume. Blocking the expression of anti-apoptotic Bcl-2 can enhance the sensitivity of cancerous cells to anti-cancer drugs and the apoptosis rate. Therefore, nanoformulations with siRNA can be promoted as an adjuvant therapy in combination with anti-cancer drugs.

Immunomodulatory Drugs: New Options for the Treatment of Myelodysplastic Syndromes

Myelodysplastic syndromes (MDS) are common adult hematologic disorders characterized by ineffective hematopoiesis with progressive cytopenia and a risk of evolving into currently incurable acute myeloid leukemia. Until recently, the only treatment was bone marrow transplantation, but, over the past few years, a new therapeutic approach based on immunomodulatory drugs (IMiD) has been developed. IMiDs belong to a therapeutic class whose progenitor is thalidomide, a synthetic derivative of glutamate that was initially used because of its sedative and antiemetic properties but was then withdrawn because of its teratogenic effects. IMiDs represent a major advance in the treatment of multiple myeloma at different disease stages, 5q minus syndrome, acute myeloid leukemia with the 5q deletion, mantle cell lymphoma, relapsing or unresponsive high-grade lymphoma, and relapsing indolent lymphoma. Medical databases and conference proceedings were searched to identify articles and clinical trials that have investigated or are investigating the use of IMiDs on MDS. An important part of their in vivo efficacy is attributed to their immunomodulatory properties because they potentiate the immune response by restoring dendritic cell function and inhibiting T-cell regulatory activity, which leads to the activation of T lymphocytes and natural killer T cells by increasing the production of interleukin-2 and interferon gamma. IMiDs are characterized by antitumoral and antiangiogenic activities, and they also induce the apoptosis of neoplastic cells. Thalidomide and its derivative lenalidomide have been proposed for the treatment of MDS because of their action on the immune mechanisms that appear to play an important role in the pathophysiology of this syndrome. This article examines the pharmacology and molecular action of IMiDs and the evidence of their efficacy in treating patients with MDS in different risk classes.

NFATc2 Is a Potential Therapeutic Target in Human Melanoma

The identification of intracellular signaling pathways that promote cell proliferation and resistance to cell death may lead to the development of improved treatment for advanced melanoma. Here we show that the calcineurin/nuclear factor of activated T cells c2 (NFATc2) pathway has an antiapoptotic role in melanoma cells. Expression of NFATc2 was constitutive in vitro and in vivo in human melanoma, and cyclosporin A (CsA) treatment of melanoma cells led to downmodulation of NFATc2. Inhibition of the calcineurin/NFAT pathway by CsA, or by NFATc2 silencing, led to modulation of cell cycle inhibitors and apoptosis-related proteins such as Apollon, and promoted caspase-dependent apoptosis of neoplastic cells. Calcineurin/NFATc2 targeting significantly enhanced melanoma cell death induced by antitumor agents, such as MEK- or BRAF(V600E)-specific inhibitors, and tumor necrosis factor-related apoptosis-inducing ligand, which trigger the intrinsic or extrinsic pathway of apoptosis, respectively. These findings identify NFATc2 as a potential therapeutic target in melanoma.

Ibandronate increases the expression of the pro-apoptotic gene FAS by epigenetic mechanisms in tumor cells

There is growing evidence that aminobisphosphonates like ibandronate show anticancer activity by an unknown mechanism. Biochemically, they prevent posttranslational isoprenylation of small GTPases, thus inhibiting their activity. In tumor cells, activated RAS-GTPase, the founding member of the gene family, down-regulates the expression of the pro-apoptotic gene FAS via epigenetic DNA-methylation by DNMT1. We compared ibandronate treatment in neoplastic human U-2 osteosarcoma and in mouse CCL-51 breast cancer cells as well as in the immortalized non-neoplastic MC3T3-E1 osteoblastic cells. Ibandronate attenuated cell proliferation in all cell lines tested. In the neoplastic cells we found up-regulation of caspases suggesting apoptosis. Further we found stimulation of FAS-expression as a result of epigenetic DNA demethylation that was due to down-regulation of DNMT1, which was rescued by re-isoprenylation by both geranylgeranyl-pyrophosphate and farnesylpyrophosphate. In contrast, ibandronate did not affect FAS and DNMT1 expression in MC3T3-E1 non-neoplastic cells. Data suggest that bisphosphonates via modulation of the activity of small-GTPases induce apoptosis in neoplastic cells by DNA-CpG-demethylation and stimulation of FAS-expression. In conclusion the shown epigenetic mechanism underlying the anti-neoplastic activity of farnesyl-transferase-inhibition, also explains the clinical success of other drugs, which target this pathway.

Phase II study of AZD2171 for the treatment of patients with myelodysplastic syndromes.

6570 Background: Inhibition of vascular endothelial growth factor receptors (VEGFR) can block growth and trigger apoptosis in neoplastic cells. AZD2171 (cediranib) is a highly potent, orally bioavailable, VEGFR-1/2 inhibitor. We conducted a phase II study of the efficacy of AZD2171 for the treatment of MDS. Methods: Adults with MDS (IPSS Int-2 or High) were eligible if they exhibited adequate organ function and ECOG 0-2. The primary endpoint was proportion of responses according to the IWG criteria assessed at one and every 3 months. Prior investigation of cediranib at 45 mg daily in patients with acute leukemia demonstrated toxicity concerns and therefore, the starting dose of this study was lowered to 30 mg daily. Results: A total of 16 pts with MDS (median age 73 years) were enrolled at a 30 mg starting dose, and all were evaluable. Median baseline marrow blasts were 12.0 % (range 2-18); 3 pts (18.8 %) had low, 6 (37.5 %) intermediate, and 7 (43.8 %) had high risk cytogenetics. Prior therapy included azacitidine (n=7), decitabine (n=2), cytarabine (n=2), erythropoietin-stimulating agents (ESAs) (n=2), lenalidomide (n=1), or none (n=6). Patients were treated for a median of two 28-day cycles (range 1 to 11). There were no confirmed responses. Patients with baseline blasts > 5% showed no significant reduction in the blast count at 4 and 12 weeks. Median OS was 4.7 mo (95% CI: 2.6 – 11.6). Median TTP was 3.8 mo (95% CI: 1.7 – 10.8). Grade 4 hematological adverse events at least possibly related to cediranib were neutropenia (n=2) and thrombocytopenia (n=4). Grade 3 hematological adverse events at least possibly related to study treatment included: neutropenia (n=3), thrombocytopenia (n=2), and anemia (n=2). Grade 3 non-hematological adverse events included fatigue (n=4), dyspnea (n=3), dehydration (n=2), diarrhea (n=2), nausea (n=2), asthenia (n=1), and hypertension (n=1). Hypertension and proteinuria was uncommon with the 30 mg/day dose. Conclusions: With no confirmed response from 16 patients, cediranib was determined to be ineffective at a dose of 30 mg daily in our patient population. Supported by NCI N01-CM62205, NCI P30-CA014520 and the UW Carbone Comprehensive Cancer Center.