Efficacy and safety of novel carbapenem-ß-lactamase inhibitor combinations: imipenem-cilastatin/relebactam results from randomized controlled trials.

Background: Gram-negative bacteria is a global public health problem. Treatment options include novel beta-lactamase inhibitors. Objectives: The objective of this study was to collect information on the efficacy and safety of novel ß-lactamase inhibitor combinations such as imipenem-cilastatin/relebactam (IMI/REL). Methods: In order to comprehensively evaluate the clinical, microbiological, and adverse events outcomes, a meta-analysis was conducted on clinical trials comparing novel ß-lactamase inhibitor combinations with existing comparator therapies. Results: Four studies comprising 948 patients were included in the analysis. IMI/REL therapy demonstrated similar clinical responses to comparators across various treatment visits, including discontinuation of intravenously administered therapy visits [DCIV, RR = 1.00 (0.88, 1.12)], early follow-up visits [EFU, RR = 1.00 (0.89, 1.14)], late follow-up visits [LFU, RR = 1.00 (0.88, 1.13)]. Moreover, no significant difference in the microbiologic response of MITT patients was observed between IMI/REL and comparators across DCIV [RR = 0.99 (0.89, 1.11)], EFU [RR = 1.01 (0.95, 1.07)], and LFU visits [RR = 1.00 (90.94, 1.07)]. In terms of safety, therapy with IMI/REL and comparators exhibited similar risks of at least one adverse event (AE), drug-related AEs, and discontinuation due to AEs. The incidence of serious AEs (SAEs) was significantly lower in the IMI/REL group compared to the comparison groups. The predominant AEs were gastrointestinal disorders, with no significant difference observed between the IMI/REL group and comparators. Conclusion: The clinical and microbiologic response to IMI/REL in the treatment of bacterial infection was comparable to that of the comparator. Furthermore, the incidence of AEs and the tolerability of IMI/REL were similar among the comparators. Based on these findings, IMI/REL can be considered as a viable alternative treatment option.

Identification and characterization of the Cucurbitacins, a novel class of small-molecule inhibitors of Tropomyosin receptor kinase a.

BACKGROUND: NGF-TrkA is well known to play a key role in propagating and sustaining pruritogenic signals, which form the pathology of chronic pruritus. Inhibition of NGF-TrkA is a known strategy for the treatment of pruritus. In the present paper, we describe the identification, in vitro characterization, structure-activity analysis, and inhibitory evaluation of a novel TrkA inhibitory scaffold exemplified by Cucurbitacins (Cus). METHODS: Cus were identified as TrkA inhibitors in a large-scale kinase library screen. To obtain structural models of Cus as TrkA inhibitors, AutoDock was used to explore their binding to TrkA. Furthermore, PC12 cell culture systems have been used to study the effects of Cus and traditional Chinese medicinal plants (Tian Gua Di and bitter gourd leaf) extracts on the kinase activity of TrkA. RESULTS: Cus block the phosphorylation of TrkA on several tyrosine sites, including Tyr490, Tyr674/675, and Tyr785, and inhibit downstream Akt and MAPK phosphorylation in response to NGF in PC12 cell model systems. Furthermore, traditional Chinese medicinal plants (Tian Gua Di and bitter gourd leaf) containing Cu extracts were shown to inhibit the phosphorylation of TrkA and Akt. These data reveal mechanisms, at least partly, of the anti-pruritus bioactivity of Cus. CONCLUSION: Taken together, with the recent discovery of the important role of TrkA as a therapeutic target, Cus could be the basis for the design of improved TrkA kinase inhibitors, which could someday help treat pruritus.

Celastrol induce apoptosis of human multiple myeloma cells involving inhibition of proteasome activity.

Celastrol exhibits anticancer activity and has a number of potential molecular targets. Among them, the proteasome has attracted particular attention. Although celastrol inhibits multiple myeloma (MM) cell proliferation, the induction of proteasome-inhibitory activity by celastrol in MM cells at the cellular level and in tumors of mice bearing xenografts has not been confirmed. In the present study, we found that celastrol inhibited the caspase-like (ß1), trypsin-like (ß2) and chymotrypsin-like (ß5) proteasome activities of purified human 20S proteasomes, with half-maximal inhibitory concentration (IC50) values of 7.1, 6.3, and 9.3 µmol/L, respectively. Celastrol also inhibited human MM cellular ß1, ß2, and ß5 proteasome activities, with IC50 values of 2.3, 2.1, and 0.9 µmol/L, respectively. After MM cells were treated with celastrol, a population of apoptotic cells and a population of cells in G0/G1 were observed. Celastrol also inhibited proteasome activity and induced apoptosis in tumor tissue. Treatment of MM.1S and RPMI 8226 tumor-bearing severe combined immunodeficiency (SCID) mice with celastrol reduced the tumor volume. In conclusion, our results reveal the effects of celastrol on proteasome activity in MM cells and shed light on the underlying mechanisms of its anticancer activity, providing a basis for developing celastrol as a potential therapeutic agent for MM.

Synthesis, characterization and in vivo evaluation of honokiol bisphosphate prodrugs protects against rats' brain ischemia-reperfusion injury.

Honokiol (HK) usage is greatly restricted by its poor aqueous solubility and limited oral bioavailability. We synthesized and characterized a novel phosphate prodrug of honokiol (HKP) for in vitro and in vivo use. HKP greatly enhanced the aqueous solubility of HK (127.54 ±â€¯15.53 mg/ml) and the stability in buffer solution was sufficient for intravenous administration. The enzymatic hydrolysis of HKP to HK was extremely rapid in vitro (T1/ 2  = 8.9 ±â€¯2.11 s). Pharmacokinetics studies demonstrated that after intravenous administration of HKP (32 mg/kg), HKP was converted rapidly to HK with a time to reach the maximum plasma concentration of ∼5 min. The prodrug HKP achieved an improved T1/2 (7.97 ±â€¯1.30 h) and terminal volume of distribution (26.02 ±â€¯6.04 ml/kg) compared with direct injection of the equimolar parent drug (0.66 ±â€¯0.01 h) and (2.90 ±â€¯0.342 ml/kg), respectively. Furthermore, oral administration of HKP showed rapid and improved absorption compared with the parent drug. HKP was confirmed to maintain the bioactivity of the parent drug for ameliorating ischemia-reperfusion injury by decreasing brain infarction and improving neurologic function. Taken together, HKP is a potentially useful aqueous-soluble prodrug with improved pharmacokinetic properties which may merit further development as a potential drug candidate.

Cucurbitacin B exerts anti-cancer activities in human multiple myeloma cells in vitro and in vivo by modulating multiple cellular pathways.

Cucurbitacin B (CuB), a triterpenoid compound isolated from the stems of Cucumis melo, has long been used to treat hepatitis and hepatoma in China. Although its remarkable anti-cancer activities have been reported, the mechanism by which it achieves this therapeutic activity remains unclear. This study was designed to investigate the molecular mechanisms by which CuB inhibits cancer cell proliferation. Our results indicate that CuB is a novel inhibitor of Aurora A in multiple myeloma (MM) cells, arresting cells in the G2/M phase. CuB also inhibited IL-10-induced STAT3 phosphorylation, synergistically increasing the anti-tumor activity of Adriamycin in vitro. CuB induced dephosphorylation of cofilin, resulting in the loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase-8. CuB inhibited MM tumor growth in a murine MM model, without host toxicity. In conclusion, these results indicate that CuB interferes with multiple cellular pathways in MM cells. CuB thus represents a promising therapeutic tool for the treatment of MM.