Discovery of allosteric regulators with clinical potential to stabilize alpha-L-iduronidase in mucopolysaccharidosis type I.

Mucopolysaccharidosis type I (MPS I) is an inherited lysosomal disease caused by lowered activity of the enzyme alpha-L-iduronidase (IDUA). Current therapeutic options show limited efficacy and do not treat some important aspects of the disease. Therefore, it may be advantageous to identify strategies that could improve the efficacy of existing treatments.

Rollable and implantable intraocular pressure sensor for the continuous adaptive management of glaucoma.

We designed and tested a new rollable and implantable medical device to directly and continuously measure intraocular pressure. Since high intraocular pressure is a leading risk factor for glaucoma, such a system could solve the difficulties encountered in the management of this condition. In fact, glaucoma is one among those pathologies that could most benefit of an adaptive patient-specific medicine device.

Bendamustine: mechanism of action and clinical data.

Bendamustine is a chemotherapeutic agent that displays a unique pattern of cytotoxicity compared with conventional alkylating agents. Bendamustine was originally synthesized in the former East German Democratic Republic in the 1960s. It was designed to have both alkylating and antimetabolite properties.

Bendamustine: rescue of an effective antineoplastic agent from the mid-twentieth century.

Although the alkylating agent bendamustine was developed in Germany in the mid-twentieth century, it has only recently come to the forefront in the rest of the world as an effective chemotherapeutic agent for the treatment of several hematologic malignancies. Based on the activity demonstrated in single-arm and randomized trials, this nitrogen mustard is approved by the US Food and Drug Administration (FDA) for the treatment of chronic lymphocytic leukemia and rituximab-refractory indolent non-Hodgkin lymphoma. The unique structural and mechanistic features of bendamustine differentiate it from other alkylating agents, providing increased stability and potency in DNA cross linking and subsequent cytotoxicity.

Conclusion and future directions.

Bendamustine is a bifunctional mechlorethamine derivative that shares similarities to other alkylators; however, the presence of a benzimidazole ring may confer "nucleoside-like" properties and may allow the stabilization of the molecule leading to longer lasting DNA damage. Though bendamustine has demonstrated promising response rates in preclinical and clinical studies, particularly in follicular lymphoma, chronic lymphocytic leukemia, diffuse B-cell lymphoma, and mantle cell lymphoma, the unique and exact mechanism of action of this agent remains unclear. Several studies have been initiated to address this question, and it is hoped that emerging data will provide the basis for more effective utilization of this interesting drug.

Mechanism of action: the unique pattern of bendamustine-induced cytotoxicity.

Bendamustine has demonstrated substantial efficacy in the treatment of hematologic malignancies and continues to distinguish itself from other alkylating agents with regard to its activity in tumor cells. The mechanistic and clinical differences associated with bendamustine may be directly related to its unique structural features. Although the precise mechanisms of action are still poorly understood, bendamustine is associated with extensive and durable DNA damage.

Pharmacokinetics and toxicity of intravesical TMX-101: a preclinical study in pigs.

Objective: • To study the pharmacokinetic and toxicity profile of intravesically administered TMX-101, with its active ingredient R-837, a synthetic Toll-like receptor (TLR)-7 agonist, in a pig model.

Materials And Methods: • TLR-7 expression was determined by immunohistochemistry in human and pig bladder tissue. • Four groups of six pigs received a 1-h intravesical instillation with R-837 of different formulations.

Intravesical Toll-like receptor 7 agonist R-837: optimization of its formulation in an orthotopic mouse model of bladder cancer.

Objective: To study the immune response caused by the intravesical administration of the immunomodulator R-837 in various formulations and to estimate its therapeutic potential for bladder cancer.

Methods: Female C57BL/6 mice were intravesically treated with different formulations of R-837, a Toll-like receptor 7 agonist used for treating genital warts and skin malignancy. The tested formulation mixtures contained different ratios of lactic acid, a thermosensitive poloxamer polymer (Lutrol F127) and 2-(hydroxypropyl)-beta-cyclodextrin (HPbetaCD).

Bendamustine (Treanda) displays a distinct pattern of cytotoxicity and unique mechanistic features compared with other alkylating agents.

Purpose: Bendamustine has shown clinical activity in patients with disease refractory to conventional alkylator chemotherapy. The purpose of this study was to characterize the mechanisms of action of bendamustine and to compare it with structurally related compounds.

Experimental Design: Bendamustine was profiled in the National Cancer Institute in vitro antitumor screen.

Pharmacological profiling of novel non-COX-inhibiting indole-pyran analogues of etodolac reveals high solid tumour activity of SDX-308 in vitro.

SDX-308 and SDX-309 are potent indole-pyran analogues of SDX-101 (R-etodolac) which has anti-tumour activity unrelated to cyclooxygenase-2 inhibition. Their cytotoxic activity was further studied herein using a well-characterized human tumour cell-line panel containing ten cell lines, as well as in 58 primary tumour cell samples from a variety of diagnoses. The indole-pyran analogues of SDX-101 were in general considerably more active in both cancer cell lines and primary tumour samples.

R-Etodolac decreases beta-catenin levels along with survival and proliferation of hepatoma cells.

Background/aims: Inhibition of hepatoma cells by cyclooxygenase (COX)-2-dependent and -independent mechanisms has been shown previously. Here, we examine the effect of Celecoxib, a COX-2-inhibitor and R-Etodolac, an enantiomer of the nonsteroidal anti-inflammatory drug Etodolac, which lacks COX-inhibitory activity, on the Wnt/beta-catenin pathway and human hepatoma cells.

Methods: Hep3B and HepG2 cell lines were treated with Celecoxib or R-Etodolac, and examined for viability, DNA synthesis, Wnt/beta-catenin pathway components, and downstream target gene expression.

R-etodolac (SDX-101) and the related indole-pyran analogues SDX-308 and SDX-309 potentiate the antileukemic activity of standard cytotoxic agents in primary chronic lymphocytic leukaemia cells.

Objective: SDX-101 is the non-cyclooxygenase 2-inhibiting R-enantiomer of the non-steroid anti-inflammatory drug etodolac, and has anti-tumour activity in chronic lymphocytic leukaemia (CLL). SDX-308 and SDX-309 are more potent, structurally related indole-pyran analogues of SDX-101. The current study was performed to investigate and quantify the cytotoxic potentiating effects resulting from a combination of either SDX-101, SDX-308 or SDX-309 with standard cytotoxic agents used in the CLL treatment today.

SDX-308, a nonsteroidal anti-inflammatory agent, inhibits NF-kappaB activity, resulting in strong inhibition of osteoclast formation/activity and multiple myeloma cell growth.

Multiple myeloma is characterized by increased osteoclast activity that results in bone destruction and lytic lesions. With the prolonged overall patient survival achieved by new treatment modalities, additional drugs are required to inhibit bone destruction. We focused on a novel and more potent structural analog of the nonsteroidal anti-inflammatory drug etodolac, known as SDX-308, and its effects on osteoclastogenesis and multiple myeloma cells.

Lack of methylthioadenosine phosphorylase expression in mantle cell lymphoma is associated with shorter survival: implications for a potential targeted therapy.

Purpose: To determine the methylthioadenosine phosphorylase (MTAP) gene alterations in mantle cell lymphoma (MCL) and to investigate whether the targeted inactivation of the alternative de novo AMP synthesis pathway may be a useful therapeutic strategy in tumors with inactivation of this enzyme.

Experimental Design: MTAP gene deletion and protein expression were studied in 64 and 52 primary MCL, respectively, and the results were correlated with clinical behavior. Five MCL cell lines were analyzed for MTAP expression and for the in vitro sensitivity to L-alanosine, an inhibitor of adenylosuccinate synthetase, and hence de novo AMP synthesis.

Homozygous deletions of methylthioadenosine phosphorylase in human biliary tract cancers.

The p16(INK4A)/CDKN2A gene on chromosome 9p21 is a site of frequent allelic loss in human cancers, and in a subset of cases, homozygous deletions at this locus encompass the telomeric methylthioadenosine phosphorylase (MTAP) gene. The MTAP gene product is the principal enzyme involved in purine synthesis via the salvage pathway, such that MTAP-negative cancers are solely dependent on de novo purine synthesis mechanisms. Inhibitors of the de novo pathway can then be used to selectively blockade purine synthesis in cancer cells while causing minimal collateral damage to normal cells.

Concordant loss of MTAP and p16/CDKN2A expression in gastroesophageal carcinogenesis: evidence of homozygous deletion in esophageal noninvasive precursor lesions and therapeutic implications.

The gene that encodes methylthioadenosine phosphorylase (MTAP), an enzyme involved in adenine and methionine salvage pathways, is located on chromosome 9p21 telomeric to the p16INK4A/CDKN2A tumor suppressor gene. Inactivation of the p16INK4A/CDKN2A gene occurs by three different mechanisms: hypermethylation of the gene promoter, intragenic mutation coupled with loss of the second allele, and homozygous deletion. Immunohistochemical labeling for the p16INK4A/CDKN2A gene product parallels gene status but does not elucidate the mechanism of gene inactivation.

Concordant loss of MTAP and p16/CDKN2A expression in pancreatic intraepithelial neoplasia: evidence of homozygous deletion in a noninvasive precursor lesion.

The p16INK4A/CDKN2A (p16) gene on chromosome 9p21 is inactivated in >90% of invasive pancreatic cancers. In 40% of pancreatic cancers the p16 gene is inactivated by homozygous deletion, in 40% by an intragenic mutation coupled with loss of the second allele, and in 10-15% by hypermethylation of the p16 gene promoter. Immunohistochemical labeling for the p16 gene product parallels gene status, but does not provide information of the mechanism of p16 gene inactivation.

SDX-101, the R-enantiomer of etodolac, induces cytotoxicity, overcomes drug resistance, and enhances the activity of dexamethasone in multiple myeloma.

In this study we report that R-etodolac (SDX-101), at clinically relevant concentrations, induces potent cytotoxicity in drug-sensitive multiple myeloma (MM) cell lines, as well as in dexamethasone (MM.1R)-, doxorubicin (Dox40/RPMI8226)-, and bortezomib (DHL4)-resistant cell lines. Immunoblot analysis demonstrates that R-etodolac induces apoptosis characterized by caspase-8, -9, and -3 and PARP (poly-ADP [adenosine diphosphate]-ribose polymerase) cleavage and down-regulation of cyclin D1 expression.

Cell death of bioenergetically compromised and transcriptionally challenged CLL lymphocytes by chlorinated ATP.

Myeloid cell leukemia-1 (MCL-1) acts as a key survival factor for chronic lymphocytic leukemia (CLL) cells. In addition, dissipation of cellular bioenergy may impose a lethal effect on these quiescent cells. Previously, in multiple myeloma cell lines we demonstrated that halogenated adenosine (8-Cl-Ado) was phosphorylated to triphosphate (8-Cl-adenosine triphosphate [ATP]), which preferentially incorporated into mRNA and inhibited RNA synthesis by premature transcription termination.

The R-enantiomer of the nonsteroidal antiinflammatory drug etodolac binds retinoid X receptor and induces tumor-selective apoptosis.

Prostate cancer is often slowly progressive, and it can be difficult to treat with conventional cytotoxic drugs. Nonsteroidal antiinflammatory drugs inhibit the development of prostate cancer, but the mechanism of chemoprevention is unknown. Here, we show that the R-enantiomer of the nonsteroidal antiinflammatory drug etodolac inhibited tumor development and metastasis in the transgenic mouse adenocarcinoma of the prostate (TRAMP) model, by selective induction of apoptosis in the tumor cells.

Homozygous deletion of the MTAP gene in invasive adenocarcinoma of the pancreas and in periampullary cancer: a potential new target for therapy.

Methylthioadenosine phosphorylase (MTAP) plays an important role in the salvage pathway for the synthesis of adenosine. Novel chemotherapeutic strategies exploiting the selective loss of MTAP function in cancers have been proposed. The MTAP gene, on chromosome 9p21, is frequently included within homozygous deletions of the p16INK4A/ CDKN2A gene.

Inhibition of HER-kinase activation prevents ERK-mediated degradation of PPARgamma.

R-etodolac, a nonsteroidal anti-inflammatory drug, inhibits the progression of CWRSA6 androgen-independent and LuCaP-35 androgen-dependent prostate cancer xenograft growth through downregulation of cyclin D1 expression via the PPARgamma pathway. PPARgamma protein degradation, observed post-R-etodolac treatment, resulted from phospho-MAP kinase (p44/42) induction by R-etodolac negatively regulating PPARgamma function. Negative regulation of PPARgamma was overcome by a combination regimen of R-etodolac with the HER-kinase axis inhibitor, rhuMab 2C4, which demonstrated an additive antitumor effect.