Bcl-XL antisense oligonucleotides coupled with antennapedia enhances radiation-induced apoptosis in pancreatic cancer

Pancreatic Cancer: Nucleic Acid Drug Discovery and Targeted Therapy

Pancreatic cancer (PC) is one of the most lethal cancers with an almost 10% 5-year survival rate. Because PC is implicated in high heterogeneity, desmoplastic tumor-microenvironment, and inefficient drug-penetration, the chemotherapeutic strategy currently recommended for the treatment of PC has limited clinical benefit. Nucleic acid-based targeting therapies have become strong competitors in the realm of drug discovery and targeted therapy. A vast evidence has demonstrated that antibody-based or alternatively aptamer-based strategy largely contributed to the elevated drug accumulation in tumors with reduced systematic cytotoxicity. This review describes the advanced progress of antisense oligonucleotides (ASOs), small interfering RNAs (siRNAs), microRNAs (miRNAs), messenger RNA (mRNAs), and aptamer-drug conjugates (ApDCs) in the treatment of PC, revealing the bright application and development direction in PC therapy.

Overcoming Gemcitabine Resistance in Pancreatic Cancer Using the BCL-XL-Specific Degrader DT2216

Pancreatic cancer is the third most common cause of cancer-related deaths in the United States. Although gemcitabine is the standard of care for most patients with pancreatic cancer, its efficacy is limited by the development of resistance. This resistance may be attributable to the evasion of apoptosis caused by the overexpression of BCL-2 family antiapoptotic proteins. In this study, we investigated the role of BCL-XL in gemcitabine resistance to identify a combination therapy to more effectively treat pancreatic cancer. We used CRISPR-Cas9 screening to identify the key genes involved in gemcitabine resistance in pancreatic cancer. Pancreatic cancer cell dependencies on different BCL-2 family proteins and the efficacy of the combination of gemcitabine and DT2216 (a BCL-XL proteolysis targeting chimera or PROTAC) were determined by MTS, Annexin-V/PI, colony formation, and 3D tumor spheroid assays. The therapeutic efficacy of the combination was investigated in several patient-derived xenograft (PDX) mouse models of pancreatic cancer. We identified BCL-XL as a key mediator of gemcitabine resistance. The combination of gemcitabine and DT2216 synergistically induced cell death in multiple pancreatic cancer cell lines in vitro In vivo, the combination significantly inhibited tumor growth and prolonged the survival of tumor-bearing mice compared with the individual agents in pancreatic cancer PDX models. Their synergistic antitumor activity is attributable to DT2216-induced degradation of BCL-XL and concomitant suppression of MCL-1 by gemcitabine. Our results suggest that DT2216-mediated BCL-XL degradation augments the antitumor activity of gemcitabine and their combination could be more effective for pancreatic cancer treatment.

Retinal ganglion cell loss in an ex vivo mouse model of optic nerve cut is prevented by curcumin treatment

Retinal ganglion cell (RGC) loss is a pathologic feature common to several retinopathies associated to optic nerve damage, leading to visual loss and blindness. Although several scientific efforts have been spent to understand the molecular and cellular changes occurring in retinal degeneration, an effective therapy to counteract the retinal damage is still not available. Here we show that eyeballs, enucleated with the concomitant optic nerve cut (ONC), when kept in PBS for 24 h showed retinal and optic nerve degeneration. Examining retinas and optic nerves at different time points in a temporal window of 24 h, we found a thinning of some retinal layers especially RGC's layer, observing a powerful RGC loss after 24 h correlated with an apoptotic, MAPKs and degradative pathways dysfunctions. Specifically, we detected a time-dependent increase of Caspase-3, -9 and pro-apoptotic marker levels, associated with a strong reduction of BRN3A and NeuN levels. Importantly, a powerful activation of JNK, c-Jun, and ERK signaling (MAPKs) were observed, correlated with a significant augmented SUMO-1 and UBC9 protein levels. The degradation signaling pathways was also altered, causing a significant decrease of ubiquitination level and an increased LC3B activation. Notably, it was also detected an augmented Tau protein level. Curcumin, a powerful antioxidant natural compound, prevented the alterations of apoptotic cascade, MAPKs, and SUMO-1 pathways and the degradation system, preserving the RGC survival and the retinal layer thickness. This ex vivo retinal degeneration model could be a useful method to study, in a short time window, the effect of neuroprotective tools like curcumin that could represent a potential treatment to contrast retinal cell death.

Biological determinants of radioresistance and their remediation in pancreatic cancer

Despite recent advances in radiotherapy, a majority of patients diagnosed with pancreatic cancer (PC) do not achieve objective responses due to the existence of intrinsic and acquired radioresistance. Identification of molecular mechanisms that compromise the efficacy of radiation therapy and targeting these pathways is paramount for improving radiation response in PC patients. In this review, we have summarized molecular mechanisms associated with the radio-resistant phenotype of PC. Briefly, we discuss the reversible and irreversible biological consequences of radiotherapy, such as DNA damage and DNA repair, mechanisms of cancer cell survival and radiation-induced apoptosis following radiotherapy. We further describe various small molecule inhibitors and molecular targeting agents currently being tested in preclinical and clinical studies as potential radiosensitizers for PC. Notably, we draw attention towards the confounding effects of cancer stem cells, immune system, and the tumor microenvironment in the context of PC radioresistance and radiosensitization. Finally, we discuss the need for examining selective radioprotectors in light of the emerging evidence on radiation toxicity to non-target tissue associated with PC radiotherapy.

Downregulation of the expression of B‑cell lymphoma-extra large by RNA interference induces apoptosis and enhances the radiosensitivity of non‑small cell lung cancer cells

B-cell lymphoma-extra large (Bcl-xL), an important member of anti-apoptotic Bcl-2 family, is involved in tumor progression and development. The overexpression of Bcl-xL is associated with radioresistance of human malignancies. The present study aimed to investigate the inhibitory effect of small interfering RNA (siRNA) on the expression of Bcl-xL in the A549 non-small lung cancer (NSCLC) cell line, and its role in inducing the apoptosis and increasing the radiosensitivity of A549 cells. An siRNA expression vector, pSilencer4-CMVneo-short hairpin (sh)RNA, was constructed and stably transfected into A549 cells. The effects of Bcl-xL-shRNA on cell proliferation, apoptosis and the protein expression levels of associated proteins were assessed in vitro in the A549 cells. The radiosensitivity of the A549 cells was evaluated using a clonogenic cell survival assay. The results demonstrated that the sequence-specific siRNA targeting Bcl-xL efficiently and specifically downregulated the mRNA and protein expression levels of Bcl-xL. The RNA interference-mediated downregulation in the expression of Bcl-xL inhibited cell proliferation, induced apoptosis and reduced the radioresistance of the NSCLC cells. These findings suggested that Bcl-xL may be a promising therapeutic approach for the treatment of NSCLC.

High expression of erythropoietin-producing hepatoma cell line-B2 (EphB2) predicts the efficiency of the Qingyihuaji formula treatment in pancreatic cancer CFPAC-1 cells through the EphrinB1-EphB2 pathway

Our previous study demonstrated that inhibition of erythropoietin-producing hepatoma cell line-B2 (EphB2) expression resulted in the promotion of cancer growth, with EphB2 acting as a tumor suppressor in pancreatic cancer. Qingyihuaji formula (QYHJ), a traditional Chinese medicine, acts as an independent protective factor for pancreatic cancer patient survival and different patients have shown various responses to QYHJ treatment. In the current study, the different effects on tumor growth inhibition following QYHJ treatment in cells with different levels of EphB2 expression were investigated to reveal the mechanism. A subcutaneously transplanted tumor model using cancer cells with different levels of EphB2 expression were established in vivo and received a four-week QYHJ intervention. Tumor weight inhibitory rate and tumor volume deflation were evaluated. The cell cycle and apoptosis were analyzed by flow cytometry, and reverse transcription polymerase chain reaction and western blot analysis were used to assess mRNA and protein levels. The results showed that the tumor weight inhibitory rate was 31.40, 31.33 and 18.36% in CFPAC-1, CFPAC-1 control RNAi and CFPAC-1 EphB2 RNAi cells following QYHJ treatment, respectively. A statistically significant difference was identified in CFPAC-1 (P<0.05) and CFPAC-1 control RNAi (P<0.01) cells. In addition, a statistically significant increase was identified in the G0/G1 phase population (P<0.05) and a statistically significant decrease was identified in the S phase population (P<0.05) in CFPAC-1 and CFPAC-1 control RNAi cells; however, no significant difference was identified in the CFPAC-1 EphB2 RNAi cells following QYHJ treatment. QYHJ upregulated the mRNA and protein level of Eph receptor-interacting B1 (EphrinB1) in the cells that were expressing different levels of EphB2, however, QYHJ did not regulate EphB2 expression. In CFPAC-1 and CFPAC-1 control RNAi cells, the QYHJ treatment resulted in a statistically significant decrease in cyclin-dependent kinase 6 (CDK6) mRNA (P<0.05) and protein (P<0.05) levels. The high expression of EphB2 predicted the superior response rate to the QYHJ treatment through a mechanism of inhibiting the cell cycle by an EphrinB1-EphB2-induced CDK6 decrease in CFPAC-1 cells. Therefore, EphB2 acts as a predictive factor for QYHJ treatment in pancreatic cancer CFPAC-1 cells.

Let-7c governs the acquisition of chemo- or radioresistance and epithelial-to-mesenchymal transition phenotypes in docetaxel-resistant lung adenocarcinoma

MicroRNA (miRNA) expression and functions have been reported to contribute to phenotypic features of tumor cells. Although targets and functional roles for many miRNAs have been described in lung adenocarcinoma (LAD), their pathophysiologic roles in phenotypes of chemoresistant LAD cells are still largely unclear. Previously, docetaxel (DTX)-resistant LAD cell lines (SPC-A1/DTX and H1299/DTX) were established by our laboratory and displayed chemo- or radioresistance and mesenchymal features with enhanced invasiveness and motility. Unbiased miRNA profiling indicated that let-7c (MIRLET7C) was significantly downregulated in SPC-A1/DTX cells. Ectopic let-7c expression increased the in vitro and in vivo chemo- or radiosensitivity of DTX-resistant LAD cells through enhanced apoptosis, reversal of epithelial-to-mesenchymal phenotypes, and inhibition of in vivo metastatic potential via inactivation of Akt phosphorylation, whereas a let-7c inhibitor decreased the chemo- or radiosensitivity of parental cells. Further investigation suggested that let-7c significantly reduced the luciferase activity of a Bcl-xL 3'-UTR-based reporter, concordant with reduced Bcl-xL protein levels. Additionally, siRNA-mediated Bcl-xL knockdown mimicked the same effects of let-7c precursor, and enforced Bcl-xL expression partially rescued the effects of let-7c precursor in DTX-resistant LAD cells. Furthermore, we found that Bcl-xL was significantly upregulated in DTX-nonresponding LAD tissues, and its expression was inversely correlated with let-7c expression. This study suggests an important role for let-7c in the molecular etiology of chemoresistant lung adenocarcinoma.

Lentivirus-mediated overexpression of TGF-β inducible early gene 1 inhibits SW1990 pancreatic cancer cell growth

TIEG1 (TGF-β inducible early gene 1) plays a significant role in regulating cell proliferation and apoptosis in various cell types. Previous studies have shown a close relationship between the expression level of TIEG1 and various cancers, including breast, prostate, colorectal and pancreatic cancer. In this study, we up-regulated the gene expression of TIEG1 in SW1990 pancreatic cancer cell line by a lentivirus transfection system and investigated its potential as a therapeutic target for pancreatic cancer. The results showed that lentivirus-mediated overexpression of TIEG1 gene inhibited human pancreatic cancer SW1990 cell proliferation and caused the cell cycle arrest at the G1-phase in vitro. SW1990 cells transduced with lenti-TIEG1 showed significant inhibition of colony formation and cancer cell growth in 3-D culture model. Moreover, overexpression of TIEG1 gene significantly slowed the growth of SW1990 xenografts in nude mice. Taken together, these data provided evidence that overexpression of TIEG1 gene by a lentivirus transfection system led to suppressed human pancreatic cancer cell growth and might therefore be a feasible approach in the clinical management of pancreatic cancer.

Adenovirus-mediated siRNA targeting Bcl-xL inhibits proliferation, reduces invasion and enhances radiosensitivity of human colorectal cancer cells

Introduction

Bcl-xL, an important member of anti-apoptotic Bcl-2 family, plays critical roles in tumor progression and development. Previously, we have reported that overexpression of Bcl-xL was correlated with prognosis of colorectal cancer (CRC) patients. The aim of this study was to investigate the association of Bcl-xL expression with invasion and radiosensitivity of human CRC cells.

Methods

RT-PCR and Western blot assays were performed to determine the expression of Bcl-xL mRNA and protein in CRC cells and normal human intestinal epithelial cell line. Then, adenovirus-mediated RNA interference technique was employed to inhibit the expression of Bcl-xL gene in CRC cells. The proliferation of CRC cells was analyzed by MTT and colony formation assay. The migration and invasion of CRC cells was determined by wound-healing and tranwell invasion assays. Additionally, the in vitro and in vivo radiosensitivity of CRC cells was determined by clonogenic cell survival assay and murine xnograft model, respectively.

Results

The levels of Bcl-xL mRNA and protein expression were significantly higher in human CRC cells than in normal human intestinal epithelial cell line. Ad/shBcl-xL could significantly reduce the expression of Bcl-xL protein in CRC cells. Also, we showed that adenovirus-mediated siRNA targeting Bcl-xL could significantly inhibit proliferation and colony formation of CRC cells. Ad/shBcl-xL could significantly suppress migration and invasion of CRC cells. Moreover, Ad/shBcl-xL could enhance in vitro and in vivo radiosensitivity of CRC cells by increasing caspase-dependent apoptosis.

Conclusions

Targeting Bcl-xL will be a promising strategy to inhibit the metastatic potential and reverse the radioresistance of human CRC.

Targeting apoptosis signaling in pancreatic cancer

The ability to escape apoptosis or programmed cell death is a hallmark of human cancers, for example pancreatic cancer. This can promote tumorigenesis, since too little cell death by apoptosis disturbs tissue homeostasis. Additionally, defective apoptosis signaling is the underlying cause of failure to respond to current treatment approaches, since therapy-mediated antitumor activity requires the intactness of apoptosis signaling pathways in cancer cells. Thus, the elucidation of defects in the regulation of apoptosis in pancreatic carcinoma can result in the identification of novel targets for therapeutic interference and for exploitation for cancer drug discovery.

RNAi targeting EZH2 inhibits tumor growth and liver metastasis of pancreatic cancer in vivo

The function of EZH2 in tumorigenesis and liver metastasis of pancreatic cancer has never been elucidated in vivo. EZH2 was overexpressed in pancreatic carcinomas and its overexpression was associated with tumor differentiation and pT status. Suppression of EZH2 caused a significant growth inhibition of pancreatic cancer cells in vitro and markedly diminished their tumorigenicity in vivo. Knock-down of EZH2 inhibited liver metastasis of pancreatic cancer in vivo. EZH2 has a crucial role in tumor growth and liver metastasis of pancreatic cancer.

Molecular targeted therapies for diffuse large B-cell lymphoma based on apoptosis profiles

Diffuse large B-cell lymphoma (DLBCL) is the most common type of adult non-Hodgkin lymphoma and is treated with chemotherapy in combination with rituximab. Despite this aggressive therapy, the disease is fatal in 30-40% of patients. Inhibition of the apoptosis signalling pathways is strongly related to response to chemotherapy and eventual clinical outcome. In order to survive, lymphoma cells depend on disruption of the apoptosis pathway by mutations in apoptosis inducing genes or by continuous expression of anti-apoptotic proteins. The development of molecules targeting these apoptosis inhibitors provides a very promising opportunity to specifically target tumour cells without toxicity to non-malignant cells in DLBCL patients. Sensitivity for most of these antagonists can be predicted based on biological markers, suggesting the possibility of pre-defining patients who will most likely benefit from these targeted therapies. Experimental therapies aimed at restoring the upstream apoptosis pathway or targeting apoptosis inhibitors are currently being tested in clinical trials and are expected to be effective particularly in chemotherapy-refractory DLBCL, providing hope for patients who are refractory to current therapies.

Apoptosis pathways and their therapeutic exploitation in pancreatic cancer

Resistance to apoptosis (programmed cell death) is a characteristic feature of human malignancies including pancreatic cancer, which is one of the leading causes of cancer deaths in the western world. Defects in this intrinsic cell death program can contribute to the multistep process of tumorigenesis, because too little cell death can disturb tissue homeostasis. Further, blockade of apoptosis pathways can cause treatment failure, because intact apoptosis signalling cascades largely mediate therapy-induced cytotoxicity. The elucidation of apoptosis pathways in pancreatic carcinoma over the last decade has resulted in the identification of various molecular defects. How apoptosis pathways can be exploited for the treatment of pancreatic cancer will be discussed in this review.

Targeted delivery systems for oligonucleotide therapeutics

Oligonucleotides including antisense oligonucleotides and siRNA are emerging as promising therapeutic agents against a variety of diseases. Effective delivery of these molecules is critical to their successful clinical application. Targeted systems can greatly improve the efficiency and specificity of oligonucleotides delivery. Meanwhile, an effective delivery system must successfully overcome a multitude of biological barriers to enable the oligonucleotides to reach the site of action and access their biological targets. Several delivery strategies based on different platform technologies and different targeting ligands have been developed to achieve these objectives. This review aims at providing a summary and perspective on recent progress in this very active area of research.

Enhanced therapeutic effects for human pancreatic cancer by application K-ras and IGF-IR antisense oligodeoxynucleotides

AIM: To investigate the combined effects of K-ras antisense oligodeoxynucleotide (K-ras ASODN) specific to GTT point mutation at codon 12 and type Iinsulin-like growth factor receptor (IGF-IR) antisense oligodeoxynucleotide (IGF-IR ASODN) on proliferation and apoptosis of human pancreatic cancer Patu8988 cells in vitro and in vivo.

METHODS: K-ras gene point mutation and its style at codon 12 of human pancreatic cancer cell line Patu8988 were detected by using polymerase chain reaction with special sequence primers (PCR-SSP) and sequence analysis. According to the mutation style, K-ras mutation ASODN specific to K-ras point mutation at codon 12 was designed and composed. After K-ras ASODN and IGF-IR ASODN treated on Patu8988 cells respectively or cooperatively, the proliferation and morphological change of Patu8988 cells were analyzed by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, colony forming assay and transmission electron microscopy; the expression of K-ras and IGF-IR mRNA and protein in the treated cells was measured by reverse-transcript polymerase chain reaction (RT-PCR) and flow cytometry respectively; apoptosis was determined by flow cytometry. The combined antitumor activity of K-ras ASODN and IGF-IR ASODN was evaluated in BALB/c nude mice bearing human pancreatic cancer inoculated with Patu8988 cells.

RESULTS: The results of PCR-SSP and sequence analysis showed that the human pancreatic cancer cell line Patu8988 had point mutation at codon 12, and the mutation style was GGT→GTT. 2-32 μg/mL K-ras ASODN and 2-32 μg/mL IGF-IR ASODN could inhibit Patu8988 cells’ growth, induce apoptosis and decrease the expression of K-ras and IGF-IR mRNA and protein alone. However, there was much more effective inhibition of growth and induction of apoptosis by their combination than by each one alone. In tumor bearing mice, the combination of K-ras ASODN and IGF-IR ASODN showed a significant inhibitory effect on the growth of transplanted pancreatic cancer, resulting in a statistically significant difference compared with each alone.

CONCLUSION: It has been found that K-ras ASODN combined with IGF-IR ASODN could cooperatively inhibit the growth of Patu8988 cells, and induce their apoptosis via reinforcing specific down regulation of K-ras and IGF-IR mRNA and protein expression.

Bortezomib in mantle cell lymphoma

Mantle cell lymphoma (MCL) represents 6% of non-Hodgkin lymphomas, but is one of the most active fields of clinical investigation. Unfortunately, there is still no standard or curative therapy in MCL. Front-line therapy appears to benefit from intensification either through high-dose therapy with stem cell transplant consolidation or dose-intense chemotherapy with hyperfractionated cyclophosphamide, vincristine, adriamycin/doxorubicin and dexamethasone/rituximab. Most patients still relapse and a multitude of novel agents are currently being tested in this setting, including proteasome inhibitors with bortezomib (the first of its class and the first US FDA-approved drug for MCL), mTOR inhibitors, Bcl-2 inhibitors, antiangiogenesis agents and histone deacetylase inhibitors among others. An obvious effort is needed to enroll patients on clinical trials, the design of which might benefit from pharmacogenomics and a better understanding of MCL biology and its diversity.

Expanding therapeutic options in mantle cell lymphoma

Mantle cell lymphoma (MCL) still carries a poor prognosis. Chemoimmunotherapy (combination with rituximab) is the routine first-line therapy, although data strongly suggest a benefit from intensification through high-dose therapy with stem cell transplantation consolidation or dose-intense chemotherapy with HyperCVAD (fractionated cyclophosphamide/vincristine/doxorubicin/dexamethasone)/rituximab. Unfortunately, most patients still experience relapse, and a multitude of novel agents are currently being tested in this setting, including proteasome inhibitors with bortezomib (the first of its class and first Food and Drug Administration-approved drug in MCL), mammalian target of rapamycin inhibitors, Bcl-2 inhibitors, and antiangiogenesis agents, among others. Because of the relative rarity of the disease-MCL represents 6% of non-Hodgkin lymphoma-an obvious effort is needed to enroll patients on clinical trials. Not surprisingly, as in other non-Hodgkin lymphomas, MCL appears more and more as a heterogeneous disease, which might impact future clinical trial design through pharmacogenomics and hopefully help us develop smaller "molecular" relevant trials.

Enhanced Antitumor Effect of Combined Triptolide and Ionizing Radiation

PURPOSE

The lack of effective treatment for pancreatic cancer results in a very low survival rate. This study explores the enhancement of the therapeutic effect on human pancreatic cancer via the combination of triptolide and ionizing radiation (IR).

EXPERIMENTAL DESIGN

In vitro AsPC-1 human pancreatic cancer cells were treated with triptolide alone, IR alone, or triptolide plus IR. Cell proliferation was analyzed with sulforhodamine B (SRB) method and clonogenic survival; comparison of apoptosis induced by the above treatment was analyzed by annexin V-propidium iodide (PI) staining. Furthermore, the expression of apoptotic pathway intermediates was measured by the assay of caspase activity and Western blot. Mitochondrial transmembrane potential was determined by JC-1 assay. In vivo, AsPC-1 xenografts were treated with 0.25 mg/kg triptolide, 10 Gy IR, or triptolide plus IR. The tumors were measured for volume and weight at the end of the experiment. Tumor tissues were tested for terminal nucleotidyl transferase-mediated nick end labeling (TUNEL) and immunohistochemistry.

RESULTS

The combination of triptolide plus IR reduced cell survival to 21% and enhanced apoptosis, compared with single treatment. In vivo, tumor growth of AsPC-1 xenografts was reduced further in the group treated with triptolide plus IR compared with single treatment. TUNEL and immunohistochemistry of caspase-3 cleavage in tumor tissues indicated that the combination of triptolide plus IR resulted in significantly enhanced apoptosis compared with single treatments.

CONCLUSIONS

Triptolide in combination with ionizing radiation produced synergistic antitumor effects on pancreatic cancer both in vitro and in vivo and seems promising in the combined modality therapy of pancreatic cancer.

Suppression of Bcl-xL expression by a novel tumor-specific RNA interference system inhibits proliferation and enhances radiosensitivity in prostatic carcinoma cells

Bcl-xL, a novel member of anti-apoptotic Bcl-2 family that play important roles in regulating cell survival and apoptosis, is frequently overexpressed in various kinds of human cancers, including prostatic carcinoma. To explore its possibility as a therapeutic target for prostatic carcinoma, we developed a novel tumor-specific RNA interference system by using survivin promoter and employed it to suppress exogenous reporters (LUC and EGFP) and endogenous gene Bcl-xL expression and analyzed its phenotypes. We found that expression of exogenous reporters (LUC and EGFP) was specifically inhibited in tumor cells but not in normal cells. We also observed that the specific inhibition of Bcl-xL in human prostatic carcinoma cells (PC3) strongly suppressed in vitro cell proliferation and in vivo tumorigenicity. We observed significant apoptosis induction and radiosensitivity enhancement in PC3 cells by the RNA interference-mediated suppression of Bcl-xL expression. All these results indicate that inhibition of Bcl-xL expression can result in potent antitumor activity and radiosensitization in human prostatic carcinoma.

Caspase-3 antisense oligodeoxynucleotides inhibit apoptosis in gamma-irradiated human leukemia HL-60 cells

To study the inhibitory effects of caspase-3 mRNA antisense oligodeoxynucleotides (ASODNs) on apoptosis, we designed four ASODNs targeting different regions of caspase-3 mRNA and transfected them into human leukemia HL-60 cells. The transfected cells were given 10 Gy gamma-irradiation followed by incubation for 18 h and measurement of apoptosis and caspase-3 expression. Our results showed that ASODN-2 targeting the 5' non-coding region of sites -62 to -46, and ASODN-3 targeting the 5' coding region of sites -1 to 16, both reduced apoptosis measured by gel electrophoresis and flow cytometry. Hoechst 33258 staining and TUNEL assay revealed that apoptotic indexes in the ASODN-2 and ASODN-3 groups were significantly lower than those in the untransfected and mismatched oligodeoxynucleotide (MODN) groups. Immunocytochemistry, Western blotting and RT-PCR showed that expression levels of caspase-3 protein and mRNA in both ASODN-2 and ASODN-3 groups were decreased compared with those in the untransfected and MODN groups. In conclusion, caspase-3 mRNA ASODNs can inhibit gamma-radiation-induced apoptosis of HL-60 cells and reduce expression of caspase-3 protein and mRNA. The results suggest that antisense approach may be useful for therapeutic treatment of certain neurodegenerative diseases in which apoptosis is involved.

New Directions in the Treatment of Mantle Cell Lymphoma: An Overview

Mantle cell lymphoma (MCL) is one of the most challenging lymphomas to treat. In the first-line setting, high-dose therapy (HDT) and autologous stem cell transplantation or hyperCVAD/rituximab suggest benefit, especially in patients aged < 60 years. Nucleoside analogue-based regimens represent an alternate option in patients ineligible for HDT. Fludarabine in combination with cyclophosphamide or mitoxantrone has shown activity, and the results were superior with the addition of rituximab. Other cytotoxic agents, such as cladribine, clofarabine, or bendamustin, showed promising activity as well. A variety of new monoclonal antibody (MoAb) agents, such as humanized anti-CD20, alemtuzumab, anti-HLA-DR, anti-CD22 (as an immunotoxin carrier), anti-CD40, as well as MoAb-targeting TRAIL-R1 and TRAIL-R2 are being tested. Radioimmunotherapy with Yttrium 90-ibritumomab tiuxetan and Iodine 131 tositumomab have been tested alone or in combination with chemotherapy, including as part of HDT and autologous stem cell transplantation, in which they showed the best results. New vaccine modalities are exploring the use of tumor cell-based vaccines or of agents that block or activate costimulatory pathways/molecules, such as CTLA-4-Ig. Allogenic transplantation represents a potential curative option for MCL, especially nonmyeloablative transplantation, more feasible in that population. A plethora of novel biologic agents have surfaced, such as bortezomib, temsirolimus, thalidomide, lenalidomide, MoAb anti-vascular endothelial growth factor or vascular endothelial growth factor-Trap, and flavopiridol. Other targets include gene transcription through histone regulation; nuclear factor-ķB pathway; protein kinase C inhibitors; small-molecules targeting apoptosis, such as antisense Bcl-2, pan-Bcl-2 family member inhibitors; MoAb agonists of cell death receptors; caspases regulators (inhibitors of apoptosis proteins, survivin); and MDM2 antagonist regulators of p53. A molecular approach to define biomarkers might help identify subgroups of patients and help develop rational therapies.