New 2-piperazinylbenzimidazole derivatives as 5-HT3 antagonists. Synthesis and pharmacological evaluation

A series of 2-piperazinylbenzimidazole derivatives were prepared and evaluated as 5-HT3 receptor antagonists. Their 5-HT3 receptor affinities were evaluated by radioligand binding assays, and their abilities to inhibit the 5-HT-induced Bezold-Jarisch reflex in anesthetized rats were determined. Compound 7e (lerisetron, pKi = 9.2) exhibited higher affinity for the 5-HT3 receptor than did tropisetron and granisetron, while compound 7q (pKi = 7.5) had very low affinity for this receptor, showing that substitution on the N1 atom of the benzimidazole ring is essential for affinity and activity. The effect of substitution on the aromatic ring of benzimidazole by several substituents in different positions is also discussed. A strong correlation between the 5-HT3 antagonistic activity of the studied compounds and the position of substitution on the aromatic ring was established. Thus, while the 4-methoxy derivative 7m showed weak affinity for the 5-HT3 receptor (pKi = 6.7), the 7-methoxy derivative 7n exhibited the highest affinity (pKi = 9.4). Compounds 7e and 7n are now under further investigation as drugs for the treatment of nausea and emesis evoked by cancer chemotherapy and radiation.

2,3-Dihydro-2-oxo-1H-benzimidazole-1-carboxamides with selective affinity for the 5-HT(4) receptor: synthesis and structure-affinity and structure-activity relationships of a new series of partial agonist and antagonist derivatives

A series of 2,3-dihydro-2-oxo-1H-benzimidazole-1-carboxamide derivatives bearing a piperazine moiety was synthesized. Their in vitro 5-HT(4), 5-HT(3), and D(2) receptors affinities were evaluated by radioligand binding assay. For selected compounds functional studies at the 5-HT(4) receptor were made by using precontracted (by carbachol) preparations of rat esophageal tunica muscularis mucosae (TMM). The influence of the 3-substituent of the benzimidazole ring, the 4-substituent of the piperazine moiety, and the alkylene spacer was studied. Compounds with an ethyl or a cyclopropyl substituent in the 3-position of the benzimidazole ring showed moderate to high affinity (K(i) = 6.7-75.4 nM) for the 5-HT(4) receptor with selectivity over 5-HT(3) and D(2) receptors and moderate antagonist activity (pK(b) = 6.19-7.73). Compounds with an isopropyl substituent in the 3-benzimidazole position exhibited moderate and selective 5-HT(4) affinity (K(i) >/= 38.9 nM) and a partial agonist activity (5a, i.a. = 0.94) higher than that of the reference compound BIMU 8 (i.a. = 0.70). This reversal of the pharmacological activity due only to a small structural difference might confirm the existence of two binding sites on the 5-HT(4) receptor. In the alkylene spacer, a two-methylene chain is favorable to optimize the affinity and the antagonist or the partial agonist activity. In the ethyl and cyclopropyl series, 5-HT(4) antagonist activity seems to be unrelated to the size of the 4-substituent of the piperazine moiety, whereas a methyl group is optimal for high partial agonist activity in the isopropyl series; however, the presence of a butyl substituent is a favorable pattern for 5-HT(4) antagonism and even causes a reversal of the pharmacological profile in the isopropyl series (5h, pK(b) = 7.94). N-Butyl quaternization of 5a led to an improvement in affinity for the 5-HT(4) receptor and mantained the high partial agonist activity (5r, K(i) = 66.3 nM, i.a. = 0.93).

Hereditary cancer syndromes in Latino populations: genetic characterization and surveillance guidelines

Hereditary cancer predisposition syndromes comprise approximately 10% of diagnosed cancers; however, familial forms are believed to account for up to 30% of some cancers. In Hispanics, the most commonly diagnosed hereditary cancers include colorectal cancer syndromes such as, Lynch Syndrome, Familial Adenomatous Polyposis, and hereditary breast and ovarian cancer syndromes. Although the incidence of hereditary cancers is low, patients diagnosed with hereditary cancer syndromes are at high-risk for developing secondary cancers. Furthermore, the productivity loss that occurs after cancer diagnosis in these high-risk patients has a negative socio-economic impact. This review summarizes the genetic basis, phenotype characteristics, and the National Comprehensive Cancer Network's screening, testing, and surveillance guidelines for the leading hereditary cancer syndromes. The aim of this review is to promote a better understanding of cancer genetics and genetic testing in Hispanic patients.

Clinical characterization and mutation spectrum in Caribbean Hispanic families with Lynch syndrome

Lynch syndrome (LS) is an inherited form of colorectal cancer (CRC) caused by germline mutations in the mismatch repair (MMR) genes. It accounts for approximately 5% of all CRCs. The prevalence of LS among US Hispanics is unknown. The objective of this study was to describe the germline mutations of LS in Caribbean Hispanics from Puerto Rico and Dominican Republic. A total of 89 subjects were recruited through the Puerto Rico Familial Colorectal Cancer Registry and were classified according to Amsterdam and Bethesda clinical guidelines. For those tumors with lack of expression of MMR protein, gene sequencing was ordered. A total of 35 individuals with deficient MMR system were identified: 22 had MMR mutations and 13 had tumors with absent MMR protein expression. Our results show that the mutation spectrum of Caribbean Hispanic LS patients was composed mostly of MSH2 (66.7%) mutations, followed by MLH1 (25.0%). One mutation was identified in MSH6 (8.3%). A previously unidentified mutation in MLH1 gene c.2044_2045del was found in one Caribbean Hispanic family. MMR mutation-positive individuals were found to be more likely to have a prominent family history of CRC and tumors located at the proximal colon. Compared to MSH2 mutation carriers, MLH1 mutation-positive individuals were more likely to have a strong family history of CRC and LS associated cancers. Furthermore, insurance coverage for genetic testing was found to be limited in the study population with 65.1% of the individuals recruited were denied coverage. This report presents the first description of the mutation spectrum and clinicopathologic characteristics of LS Caribbean Hispanics patients.

Synthesis and structural study of pyrimidyl carbocyclic analogues of nucleosides based on cyclopentene rings

A series of 1,2-disubstituted carbonucleoside analogues of pyrimidine and 5-halopyrimidines with the unsaturated carbocycle cyclopentene was synthesized. AIM theory was applied to analyse the conformational and electronic effects of 5-halogenation.

Implementation and Outcomes of a Community-Based Educational Program for Colorectal Cancer Prevention in Hispanics

Objectives

Colorectal cancer (CRC) is the 2^nd most diagnosed cancer and leading cause of cancer death in Puerto Rico. However, CRC screening rates remain low. The aim of this study was to test the effectiveness of a Train-the-Trainers' (TTT) program to develop trainers capable of educating others within their communities about CRC prevention.

Methods

The TTT program consisted of didactics and seminars to capacitate participants to become trainers in CRC prevention. This project was evaluated using three components: (1) training workshops; (2) community educational sessions; and (3) the participant's experience as a trainer. Pre - and post-tests on CRC screening knowledge were given to TTT participants. Program effectiveness was determined by the pre- and post-tests, number of workshop participants completing a community educational session within three months of training and the number of community members reached.

Results

Among the 115 total participants, 97 participants took the pre- and post-test. There was a significant difference in the scores for the pre-test (M = 10.56, SD = 2.57) and the post-test (M = 11.43, SD = 1.83) given; t (96) = -4.68, p < 0.001. A total of 955 community members were reached. Participants from the community educational sessions (n = 680) evaluated the program. 77.7% of those participants expressed intent to undergo colonoscopy screening in the future.

Conclusions

TTT was effective in preparing trainers in CRC prevention. Participants increased their knowledge about CRC prevention and successfully reached members of their community. Utilization of community trainers is an effective alternative to increase CRC education and awareness in Hispanic communities, which may positively impact CRC screening rates in this population.

Abstract 1813: Implementation and outcomes of a community-based educational program in colorectal cancer prevention

Background: Cancer is the second most common cause of death in Puerto Rico (PR) after heart disease. Colorectal cancer (CRC) is the second most commonly diagnosed cancer among both men and women. The cancer screening guidelines given by the American Cancer Society indicate that adults should begin CRC screening at the age of 50. Although self-reported CRC screening from 1997 to 2006 have showed an increase in PR, CRC screening trends are lower than in the United States. With low screening rates and high CRC mortality in PR, health promotion programs aimed at education and prevention are needed.

Methods: The purpose of this study was to evaluate a community-based educational program (Train-the-Trainer – TTTP) to increase knowledge and awareness of prevention about CRC in PR. The TTTP consisted of a formal didactic and hands-on seminar where participants were given didactic information and were trained to become trainers in CRC prevention. The TTTP was open to any adult, who was willing to become a trainer and committed to present the information in another forum using the materials provided at the TTTP. For the evaluation of this project, three main components were measured: (1) the Train the Trainers’ sessions; (2) the Participants’ Community Educational Sessions; and (3) the participant's experience delivering the training intervention. A total of five different questionnaires were design for the evaluation process of each component. Both qualitative and quantitative methods were used to collect data. Evaluations of outcomes were measured within 60-days of the TTT session.

Results: Pre- and post-tests were given to the participants of the Train-the-Trainer session (N=115). There was a significant difference in the scores for the pre-test (mean=10.56, SD=2.57) and the post-test (mean=11.43, SD=1.83); t(96)=−4.68, p&lt; 0.001); suggesting an augmentation in knowledge. Overall the participants from the community educational sessions (N=680) evaluated the program to be a success indicating that it provided them with knowledge, resources, and motivation to be screened for colorectal cancer, with 69.9% indicating their willingness to obtain a colonoscopy in the future. The trainer-to-trainee ratio was 1:6, with each participant of the TTTP training an average of 6 individuals from their own community within a 60-day period.

Conclusion: The Puerto Rico CRC TTTP was effective in capacitating individuals to become trainers in their respective communities. The TTTP was effective in increasing knowledge of CRC prevention strategies and successfully reached members of the community. Implementation of a community-based program designed to develop trainers in CRC prevention demonstrated to be feasible and effective. Community based training programs are an alternative to promote CRC education and awareness in PR and may impact CRC screening rates, with subsequent decreases in mortality.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1813. doi:10.1158/1538-7445.AM2011-1813

Synthesis and 5-HT3 receptor affinity of new quinolinecarboxylic acid derivatives

A series of quinolinecarboxylic acid amides and an ester with a quinuclidine moiety were synthesized and their in vitro affinities at 5-HT3, 5-HT4, and D2 receptors evaluated by radioligand binding assays. Highest affinity at 5-HT3 receptor corresponded to derivative 5 with Ki = 9.9 nM and with selectivity over 5-HT4 and D2 receptors. Compounds displayed moderate 5-HT3 antagonist activity (ED50 = 10.5-21.5 microg/kg i.v.). The obtained data suggest that the 5-HT3 receptor sites can accommodate the acyl group of the 2-quinoline derivatives. The results indicate the existence of an optimal distance between the lone electron pair of the quinoline nitrogen atom and the azabicyclic nitrogen atom, and a no-pharmacophoric pocket in the 5-HT3 receptor which would hold the fragment at the position 4 of the quinoline ring.