BH3 Mimetic Peptides: An Effective Strategy to Complement Anticancer Therapy.

Apoptosis, a natural process of programmed cell death, is a promising therapeutic target as the disruption of apoptosis evolves in many diseases including cancer. Several pieces of evidence indicate that errors in apoptotic pathways result in the imbalance between cell proliferation and death, allowing cells with genetic abnormalities to survive. The intrinsic and extrinsic pathways of apoptosis utilize different caspases to execute the event of cell death through the cleavage of hundreds of proteins. Proteins from the Bcl-2 family, a pivotal component of the mitochondrial apoptosis pathway, activate the death signal either directly or indirectly involving mitochondrial translocation of Bax/Bak, which are recognized critical elements in defective apoptosis. The majority of chemotherapeutic drugs destroy cancer cells by activating the apoptotic machinery via Bcl-2/Bax-dependent process and failure of which leads to an intrinsic chemoresistance. Recent insights into the dynamic action of pro-survival Bcl-2 proteins in cancer pathogenesis and resistance has set the stage for the development of small molecules as Bcl-2 antagonist and modulators of apoptosis. The BH3-only proteins are vital inducers of the mitochondrial apoptosis mechanism that operate either by assuming the functional activity of the proapoptotic Bcl-2 family members or by impeding the antiapoptotic Bcl-2 proteins. Based on the structural interaction studies between the proapoptotic and anti-apoptotic proteins, several synthetic peptides have been designed to functionally mimic the BH3 domain, targeting directly the pro-survival Bcl-2 proteins. The "BH3-peptide mimetics" a novel class of Bcl-2 protein antagonists essentially play an important role in the treatment of malignancies as they are predicted to persuade non-receptor mediated programmed cell death. This review summarizes the most promising BH3-peptide mimetic compounds that function as selective antagonists of Bcl-2 proteins and would be effective in treating various cancers.

Enhanced anticancer efficacy of histone deacetyl inhibitor, suberoylanilide hydroxamic acid, in combination with a phosphodiesterase inhibitor, pentoxifylline, in human cancer cell lines and in-vivo tumor xenografts.

Vorinostat [suberoylanilide hydroxamic acid (SAHA)], a histone deacetylase inhibitor, shows limited clinical activity against solid tumors when used alone. The methyl xanthine drug, pentoxifylline (PENT), has been described to have antitumor properties. The aim of this study was to look for the enhanced anticancer activities of both agents when used in combination at doses lower than their respective efficacy dose when used alone. We investigated the antitumor potential of this novel combination in vitro and in vivo. The combination index was assessed for these two drugs to look for synergistic antiproliferative activity against a broad spectrum of human cancer cell lines. Consistent additive to synergistic interactions were observed in HCT116 cells when PENT was combined with SAHA at all drug tested concentrations. The combination of SAHA and PENT induces chromatin condensation and apoptosis downstream of the pan histone deacetylase inhibition and phosphodiesterase regulation, leading to subsequent cell cycle arrest at their lower tested concentrations. Further, the ability of this combination to inhibit angiogenesis, both in vitro and in vivo, was examined and a significant inhibition in tube formation in HUVEC cells and neovascularization of Matrigel plug was observed. A significant inhibition in tumor growth was observed in severe combined immunodeficient mice bearing HCT116 (colon) and PC3 (prostate) human xenografts treated with SAHA (30 mg/kg, intraperitoneal) in combination with PENT (60 mg/kg, intraperitoneal), with no loss in body weight and 100% survival. In conclusion, these findings indicate the enhanced anticancer activity of SAHA in combination with PENT both in vitro and in vivo.

Buffalo cervico-vaginal fluid proteomics with special reference to estrous cycle: heat shock protein (HSP)-70 appears to be an estrus indicator.

Cervico-vaginal fluid (CVF) plays significant roles in coitus, sperm transport, and implantation. It is believed to be a good noninvasive biomarker for various diagnostic purposes. In this study, a comprehensive proteomic analysis of buffalo CVF was performed during the estrous cycle in order to document the protein expressions, utilizing SDS-PAGE, mass spectrometry, and immunoblot. The main objective was to screen the CVF of buffalo for one or more estrus-specific proteins. A total of 416 proteins were identified in the CVF of both estrus and diestrus phases. Out of these proteins, 68 estrus-specific proteins have been extensively reviewed in the protein database. The major physiological functions of estrus CVF proteins appeared to be stress response, immune response, and metabolic. Eventually, the expression level of heat shock protein-70 in the CVF during the estrus phase, as revealed in SDS-PAGE analysis, was higher than during diestrus. The identity of the protein was confirmed by immunoblot analysis as heat shock protein-70. The findings provide a potential lead for the evaluation of these proteins for estrus detection in buffalo because CVF biomarker detection is a noninvasive technique. The mass spectrometric data of identified proteins have been deposited at the ProteomeXchange with the identifier PXD000620.

Identification of p-cresol as an estrus-specific volatile in buffalo saliva: comparative docking analysis of buffalo OBP and ß-lactoglobulin with p-cresol.

Assessment of salivary volatile compounds adopting gas chromatography-linked mass spectrometry (GC-MS) analysis revealed the presence of a total of 11 compounds in the buffalo saliva irrespective of the stages in the reproductive cycle. p-cresol was identified as an estrus-specific volatile compound in the saliva. In addition, modeling of odorant-binding protein (OBP) and ß-lactoglobulin revealed that OBP is highly stable and has strong binding affinity with p-cresol. Hydrogen bond interactions indicated that OBP is responsible for pheromone release through saliva. In contrast, ß-lactoglobulin, which belongs to the same lipocalin family as OBP, possesses less affinity to p-cresol than OBP, suggesting that it is not involved in p-cresol binding and transport. Phylogenetic characterization revealed that bovine family of OBP is separately clustered. It is suggested that p-cresol has the potential to be developed as a biomarker to detect the reproductive status in the buffalo and for behavioral manipulations.

Faecal chemical cues in water buffalo that facilitate estrus detection.

Chemo-signals are among the reliable non-invasive methods for estrus detection in mammals. Water buffalo is a silent heat animal and, hence, there is search for chemo-signals which would be effective non-invasive indicators of estrus state. We analyzed the faecal chemical cues during the estrous cycle in buffalo and to find the estrus-specific faecal volatile compounds adopting bull behavior assay. The faecal samples were collected at three phases of the estrous cycle (i.e., proestrus, estrus and postestrus) and subjected to gas chromatography-mass spectrometry analyses. We found 27 volatile compounds in the faeces of buffaloes, of which 4-methyl phenol (4mp) and trans-verbenol (tv) were found only in estrus faeces. The faecal samples of estrus buffaloes and the estrus-specific compound(s) (4mp+tv) at three different concentrations were tested for behavioral responses (flehmen and mounting behavior) in the bull. The bulls exhibited repeated flehmen when exposed to a combination of the two compounds (i.e., 4mp+tv) as compared to the individual compounds or raw faecal sample collected from buffalo when in estrus (P<0.05). However, higher number of mounting behavior was recorded when bulls were exposed to 4mp followed by a combination of the two compounds (4mp+tv) and trans-verbenol (P<0.05), in that order. By contrast, less number of mounting behavior was exhibited by bulls when exposed to the control sample (i.e., Hexadecanoic acid) (P<0.05). As inferred from the bull behavior assay, the present study suggests that the two compounds, 4 methyl phenol and trans-verbenol would be reliable indicators of estrus in buffaloes.

Ability of mice to detect estrous odor in bovine urine: roles of hormones and behavior in odor discrimination.

This study was designed to evaluate the ability of mice to discriminate cow urinary odor from different reproductive phases, with a view toward detecting the estrous phase. Experiments were also carried out to establish the relationship between androgen and mouse behaviors during estrous detection. Further, the study was also intended to establish the relationship between androgen and behaviors in estrous detection. Bovine urine was collected during estrus and non-estrous periods, i.e., prepubertal, preovulatory, ovulatory, postovulatory, pregnancy, and lactation. Behavioral analyses were carried out in a Y-maze apparatus, in which the mice were acclimatized in before odor-preference tests. The number and duration of visits, and grooming behavior by male responders towards the urine samples, were recorded. Intact male mice showed a higher response towards estrus urine samples than towards non-estrous urine. By contrast, orchidectomized mice failed to discriminate estrous urine, whereas castrated mice treated with testosterone regained the ability to discriminate estrus odor. A higher level of grooming behavior was found in males exposed to estrous urine than to urine of other phases. These results suggest that normal mice have the ability to detect estrus, and that this discriminating ability is androgen dependent. The grooming behavior shown by males in response to estrous urine may be taken as a key parameters in estrous detection. The results further suggest that bovine estrous urine produces specific odors that probably involve both intraspecific and interspecific communication.