Novel sulindac derivatives: synthesis, characterisation, evaluation of antioxidant, analgesic, anti-inflammatory, ulcerogenic and COX-2 inhibition activity.

A new series of N'-(substituted phenyl)-2-(1-(4-(methylsulfinyl) benzylidene)-5-fluoro-2-methyl-1H-inden-3-yl) acetohydrazide derivatives (1 - 25) were prepared in good yields in an efficient manner. All the compounds were fully characterised by the elemental analysis and spectral data. Synthesised compounds were evaluated for antioxidant activity by DPPH method. Compounds 7 (R = 3-methoxyphenyl), 3 (R = 4-dimethylaminophenyl) and 23 (R = 2,4,5-trimethoxy phenyl) substitutions were found to be having highly potent antioxidant activity. Compound 3, with para dimethylaminophenyl substitution was found to be having highest antioxidant activity. It was further evaluated in vivo for various analgesic, anti-inflammatory, ulcerogenic and COX-2 inhibitory activity in different animal models. Lead compound 3 was found to be significant anti-inflammatory and analgesic agent. It was also evaluated for ulcerogenic activity and demonstrated significant ulcerogenic reduction activity in ethanol and indomethacin model. The LD50 of compound 3 was found to be 131 mg/kg. The animals treated with compound 3 prior to cisplatin treatment resulted in a significant reduction in COX-2 protein expression when compared to cisplatin-treated group. Sulindac derivative with para dimethylaminophenyl substitution was found to be the most potent antioxidant, anti-inflammatory and analgesic agent as well as with significant gastric sparing activity as compared to standard drug sulindac. Compound 3 significantly downregulated liver tissue COX-2 gene expression.

A small diversity library of α-methyl amide analogs of sulindac for probing anticancer structure-activity relationships.

Non-steroidal anti-inflammatory drugs (NSAIDs) have a variety of potential indications that include management of pain and inflammation as well as chemoprevention and/or treatment of cancer. Furthermore, a specific form of ibuprofen, dexibuprofen or the S-(+) form, shows interesting neurological activities and has been proposed for the treatment of Alzheimer's disease. In a continuation of our work probing the anticancer activity of small sulindac libraries, we have prepared and screened a small diversity library of α-methyl substituted sulindac amides in the profen class. Several compounds of this series displayed promising activity compared with a lead sulindac analog.

Synthesis and biological evaluation of nitric oxide-donating analogues of sulindac for prostate cancer treatment.

A series of analogues of the non-steroidal anti-inflammatory drug (NSAID) sulindac 1 were synthesised tethered to nitric oxide (NO) donating functional groups. Sulindac shows antiproliterative effects against immortal PC3 cell lines. It was previously demonstrated that the effect can be enhanced when tethered to NO releasing groups such as nitrate esters, furoxans and sydnonimines. To explore this approach further, a total of fifty-six sulindac-NO analogues were prepared and they were evaluated as NO-releasing cytotoxic agents against prostate cancer (PCa) cell lines. Compounds 1k and 1n exhibited significant cytotoxic with IC50 values of 6.1±4.1 and 12.1±3.2µM, respectively, coupled with observed nitric oxide release.

Design, synthesis, and biological evaluation of novel sulindac derivatives as partial agonists of PPARγ with potential anti-diabetic efficacy.

Peroxisome proliferator-activated receptor gamma (PPARγ) is a valuable drug target for diabetic treatment and ligands of PPARγ have shown potent anti-diabetic efficacy. However, to overcome the severe side effects of current PPARγ-targeted drugs, novel PPARγ ligands need to be developed. Sulindac, an identified ligand of PPARγ, is widely used in clinic as a non-steroidal anti-inflammatory drug. To explore its potential application for diabetes, we designed and synthesized a series of sulindac derivatives to investigate their structure-activity relationship as PPARγ ligand and potential anti-diabetic effect. We found that meta-substitution in sulindac's benzylidene moiety was beneficial to PPARγ binding and transactivation. Z rather than E configuration of the benzylidene double bond endowed derivatives with the selectivity of PPARγ activation. The indene fluorine is essential for binding and regulating PPARγ. Compared with rosiglitazone, compound 6b with benzyloxyl meta-substitution and Z benzylidene double bond weakly induced adipogenesis and PPARγ-targeted gene expression. However, 6b potently improved glucose tolerance in a diabetic mice model. Unlike rosiglitazone, 6b was devoid of apparent toxicity to osteoblastic formation. Thus, we provided some useful guidelines for PPARγ-based optimization of sulindac and an anti-diabetic lead compound with less side effects.

Synthesis of Functionalized Alkylidene Indanes and Indanones through Tandem Phosphine-Palladium Catalysis.

Densely functionalized alkylidene indanes and indanones can be prepared efficiently in one pot, in high yields with good stereoselectivities (in some cases exclusively the Z-isomer), through a route involving phosphine-catalyzed Michael addition followed by palladium-catalyzed Heck cyclization. These transformations tolerate substrates bearing various substituents around the indane/indanone motif. Employing this technology, a concise formal synthesis of sulindac, a nonsteroidal anti-inflammatory drug, has been established.

Exisulind Cell Pathways.

Cell Pathways has developed exisulind (Aptosyn), an oral apoptosis modulator and cGMP phosphodiesterase inhibitor, for the potential treatment of several oncologic indications including precancerous adenomatous polyposis coli (APC), also known as familial adenomatous polyposis (FAP), precancerous sporadic colonic polyps, cervical dysplasia and the prevention of tumor recurrence in prostate and breast cancer. An NDA filing for the treatment of precancerous APC, for which the US FDA designated exisulind a Fast Track product in July 1998, was initially expected in March 1999 [291313]. However, in January of the same year the company stated that it anticipated a delay in the NDA filing. The decision was based on unsatisfactory phase III data [308912], [313124]. In June 1999, the company completed analysis of the phase III trial data [328000] and the NDA was submitted in August 1999. An NDA was accepted for review by the FDA in October 1999 for the treatment of APC [328000], [338007], [344721], after data from three additional trials were submitted to the FDA in support of the NDA. At this time phase II/III trials were also ongoing for prostate and breast cancer recurrence [287250], [326795]. Approval for the indication of FAP had been expected by the end of 2000 [365737] but in September 2000 the FDA completed its initial review and advised Cell Pathways that exisulind will not be approved at this time. Cell Pathways has received a 'non-approvable' letter and intends to advise the FDA of its intent to amend the NDA and to request a meeting to address the deficiencies in the NDA [383249], [383560]. The first of the three additional trials submitted to the FDA in October 1999 was a 6-month, open-label trial involving 48 of the patients who completed a phase II/III study of exisulind in early 1999. After 6 months of treatment with exisulind, 25 patients who had previously been taking placebo experienced a 50% reduction in polyp formation. The patients continuing treatment with exisulind exhibited a further 50% reduction from their already reduced rate of polyp formation [344991]. The second study was an extension study of 11 patients who participated in a 6-month, open-label, phase I/II, dose-ranging, safety and efficacy trial. As of October 1999, these patients were still on therapy and had been receiving exisulind for between 36 and 50 months. They had all experienced statistically significant reductions in polyp formation rates [344991]. The third study was a double-blind, placebo-controlled safety study of 26 patients. All patients exhibited a trend of reduced new polyp formation when compared to placebo. Exisulind was generally well-tolerated by all patients during the course of the studies [344991]. In July 2000, Cell Pathways signed a marketing and distribution agreement for Canada with Paladin Labs, allowing Paladin exclusive rights to commercialize exisulind within Canada [376072]. Also in July 2000, Cell Pathways announced that patents covering methods of identifying compounds that selectively stimulate apoptosis have been allowed in Europe and Japan. The patents describe the mechanism of action of Cell Pathways' SAANDs, including exisulind, and use of that knowledge in screening for new drugs [374888]. In January 1999, the company received US-05858694 covering the mechanism of action of exisulind [311504].

Synthesis and SAR study of modulators inhibiting tRXRα-dependent AKT activation.

RXRα represents an intriguing and unique target for pharmacologic interventions. We recently showed that Sulindac and a designed analog could bind to RXRα and modulate its biological activity, including inhibition of the interaction of an N-terminally truncated RXRα (tRXRα) with the p85α regulatory subunit of phosphatidylinositol-3-OH kinase (PI3K). Here we report the synthesis, testing and SAR of a series of novel analogs of Sulindac as potential modulators for inhibiting tRXRα-dependent AKT activation. A new compound 30 was identified to have improved biological activity.

Cyclooxygenase-1-selective inhibitors based on the (E)-2'-des-methyl-sulindac sulfide scaffold.

Prostaglandins (PGs) are powerful lipid mediators in many physiological and pathophysiological responses. They are produced by oxidation of arachidonic acid (AA) by cyclooxygenases (COX-1 and COX-2) followed by metabolism of endoperoxide intermediates by terminal PG synthases. PG biosynthesis is inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs). Specific inhibition of COX-2 has been extensively investigated, but relatively few COX-1-selective inhibitors have been described. Recent reports of a possible contribution of COX-1 in analgesia, neuroinflammation, or carcinogenesis suggest that COX-1 is a potential therapeutic target. We designed, synthesized, and evaluated a series of (E)-2'-des-methyl-sulindac sulfide (E-DMSS) analogues for inhibition of COX-1. Several potent and selective inhibitors were discovered, and the most promising compounds were active against COX-1 in intact ovarian carcinoma cells (OVCAR-3). The compounds inhibited tumor cell proliferation but only at concentrations >100-fold higher than the concentrations that inhibit COX-1 activity. E-DMSS analogues may be useful probes of COX-1 biology in vivo and promising leads for COX-1-targeted therapeutic agents.

COX inhibitors Indomethacin and Sulindac derivatives as antiproliferative agents: synthesis, biological evaluation, and mechanism investigation.

Cyclooxygenase (COX) inhibitors Indomethacin and its structural analogs Sulindac exhibit cell growth inhibition and apoptosis inducing activities in various cancer cell lines via COX independent mechanisms. In this study, the molecular structures of Indomethacin and Sulindac were used as starting scaffolds to design novel analogs and their effects on the proliferation of human cancer cells were evaluated. Compared to Indomethacin and Sulindac inhibiting cancer cell proliferation with IC(50)s of more than 1 mM, the derivatives displayed significantly increased activities. Especially, one of the Indomethacin analogs inhibited the growth of a series of cancer cell lines with IC(50)s around 0.5 µM-3 µM. Mechanistic investigation revealed that the new analog was in fact a tubulin inhibitor, although the parental compound Indomethacin did not show any tubulin inhibitory activity. Tubulin polymerization assay indicated this compound inhibited tubulin assembly at high concentrations, but promoted this process at low concentrations which is a very unique mechanism. The binding mode of this compound in tubulin was predicted using the molecular docking simulation.

A novel sulindac derivative that does not inhibit cyclooxygenases but potently inhibits colon tumor cell growth and induces apoptosis with antitumor activity.

Nonsteroidal anti-inflammatory drugs such as sulindac have shown promising antineoplastic activity, although toxicity from cyclooxygenase (COX) inhibition and the suppression of prostaglandin synthesis limits their use for chemoprevention. Previous studies have concluded that the mechanism responsible for their antineoplastic activity may be COX independent. To selectively design out the COX inhibitory activity of sulindac sulfide (SS), in silico modeling studies were done that revealed the crucial role of the carboxylate moiety for COX-1 and COX-2 binding. These studies prompted the synthesis of a series of SS derivatives with carboxylate modifications that were screened for tumor cell growth and COX inhibitory activity. A SS amide (SSA) with a N,N-dimethylethyl amine substitution was found to lack COX-1 and COX-2 inhibitory activity, yet potently inhibit the growth of human colon tumor cell lines, HT-29, SW480, and HCT116 with IC(50) values of 2 to 5 micromol/L compared with 73 to 85 micromol/L for SS. The mechanism of growth inhibition involved the suppression of DNA synthesis and apoptosis induction. Oral administration of SSA was well-tolerated in mice and generated plasma levels that exceeded its in vitro IC(50) for tumor growth inhibition. In the human HT-29 colon tumor xenograft mouse model, SSA significantly inhibited tumor growth at a dosage of 250 mg/kg. Combined treatment of SSA with the chemotherapeutic drug, Camptosar, caused a more sustained suppression of tumor growth compared with Camptosar treatment alone. These results indicate that SSA has potential safety and efficacy advantages for colon cancer chemoprevention as well as utility for treating malignant disease if combined with chemotherapy.