Anticancer Agents Based on Vulnerable Components in a Signalling Pathway

Overview of the development of HBV small molecule inhibitors

Like tuberculosis and Acquired Immune Deficiency Syndrome (AIDS), hepatitis B is a globally recognized major public health threat. Although there are many small-molecule drugs for the treatment of hepatitis B, the approved drugs cannot eradicate the pathogenic culprit covalently closed circular DNA in patients, so the patients need long-term medication to control HBV amplification. Driven by a high unmet medical need, many pharmaceutical companies and research institutions have been engaged in the development of anti-HBV drugs to achieve a functional cure for chronic hepatitis B as soon as possible. This review summarizes the pathogenesis of hepatitis B virus and the research progress in the development of anti-HBV small molecule drugs, and introduces the cccDNA formation and transcription inhibitors and core inhibitors in detail, especially emphasizes the role of chinese herbal medicine in the treatment of chronic hepatitis B. Furthermore, this review proposes three potential strategies for cccDNA eradication in the future. We believe this review will provide meaningful guidance to achieve a functional cure for viral hepatitis B in the future.

Molecular bottlebrush with pH-responsive cleavable bonds as a unimolecular vehicle for anticancer drug delivery

Drug delivery systems with targeted and smart properties have emerged as an efficient strategy to overcome the challenges of cancer chemotherapy such as toxic side effects and the development of multidrug resistance. In this study, a biocompatible bottlebrush polymer poly((3-(2-bromo-2-methylpropionate)propyldimethylsilyloxy)ethyl methacrylate)-graft-poly(2-methacryloyloxyethyl phosphorylcholine) P(BIBS-EMA)-g-PMPC with pH-responsive silanol cleavable bond was designed and developed for delivery of doxorubicin. A549 cell line of human lung carcinoma was tested. The synthesized bottlebrush polymer was analyzed and characterized via Fourier transform infrared spectroscopy, FTIR, nuclear magnetic resonance spectroscopy, ¹H NMR, gel permeation chromatography, GPC, dynamic laser light scattering, DLS, and static laser light scattering, SLS, techniques. The cleavage process was also precisely studied to confirm the pH-responsiveness of such bottlebrush polymers. In vitro loading and release studies of doxorubicin as a model drug were examined and the results showed a pH-dependent release manner with a twice higher release rate under cancerous tissue conditions compared to standard physiological conditions. MTT cytotoxicity assay was also performed to prove the biocompatibility of the designed polymeric platform on healthy human cells. Due to the presence of bio-inspired poly(2-methacryloyloxyethyl phosphorylcholine) side chains in the prepared bottlebrush polymer, the formed polymer-drug complex could also exhibit effective internalization into tumor cells. These facts further support the potential use of this carrier in drug delivery applications and for further in vivo studies.

The anticancer activity of carbazole alkaloids

Chemotherapy is the first choice for the majority of cancers, but severe side effects and drug resistance restrict the actual clinical efficacy. Carbazole alkaloids, mainly from the Rutaceae family, possess favorable donor ability, good planarity, rich photophysical properties, and excellent biocompatibility. Carbazole alkaloids could not only intercalate in DNA but could also inhibit telomerase and topoisomerase and regulate protein phosphorylation. Hence, carbazole alkaloids are useful in providing lead hits/candidates for the development of novel anticancer agents. This review summarizes the research progress made regarding the anticancer properties of carbazole alkaloids, covering articles published from January 2010 to June 2021.

Caspase-3: A primary target for natural and synthetic compounds for cancer therapy

Caspases, a group of protease enzymes (cysteine proteases), exist as inactive zymogens in the cells and execute apoptosis (programmed cell death). Caspase-3, an executioner caspase, plays an imperative role in apoptosis and becomes a primary target for cancer treatment. A number of analogues of quinazoline, quinazolinone, indoloquinazolines, quinone, naphthoquinones, pyrroloiminoquinones, styrylquinolines, tetheredtetrahydroquinoline, fluoroquinolone, thiosemicarbazones, benzotriazole, pyrimidines, chalcone, and carbazoles have been reported till date, representing caspase-3 mediated apoptosis for cancer therapy. Simultaneously, plant isolates, including lysicamine, podophyllotoxin, and majoranolide, have also been claimed for caspase-3-mediated apoptosis-induced cytotoxicity. Procaspase-activating compound-1 (PAC-1) is the first FDA approved orphan drug, and its synthetic derivative WF-208 also showed fascinating caspase-3 mediated anticancer activity. Till date, a large number of compounds have been reported and patented for their caspase-3-mediated cytotoxicity and now scientist is also focusing to introduce new compounds in market to encompass anticancer activity.

Discovery of Novel 1,2,4-Oxadiazole Derivatives as Potent Caspase-3 Activator for Cancer Treatment

In the present study, a quantitative structure–activity relationship (QSAR) and docking studies were accomplished on a series of 1,2,4-oxadiazoles. The results of QSARs are reliable and have high predictive ability for both the internal (q2 = 0.610) and external (pred_r2 = 0.553) datasets with least standard error (SE; i.e., 0.130) and four principal components, which signifies the reliability of the generated model. Molecular docking was also reported by the GOLD docking program, which showed that the hydrogen bonding may be responsible for the activity, and may be further increased upon adding high electronegative substitutions.

Knockdown of lncRNA HOXA-AS3 Suppresses the Progression of Atherosclerosis via Sponging miR-455-5p

Background

Atherosclerosis can lead to multiple cardiovascular diseases, especially myocardial infarction. Long noncoding RNAs (lncRNAs) are involved in multiple diseases, including atherosclerosis. LncRNA HOXA-AS3 was found to be notably upregulated in atherosclerosis. However, the biological function of HOXA-AS3 during the occurrence and development of atherosclerosis remains unclear.

Materials and Methods

Human vascular endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (oxLDL) to mimic atherosclerosis in vitro. Gene and protein expressions in HUVECs were detected by RT-qPCR and Western blot, respectively. Cell proliferation was tested by CCK-8 and Ki67 staining. Cell apoptosis and cycle were measured by flow cytometry. Additionally, the correlation between HOXA-AS3 and miR-455-5p was confirmed by dual luciferase report assay and RNA pull-down. Finally, in vivo model of atherosclerosis was established to confirm the function of HOXA-AS3 during the development of atherosclerosis in vivo.

Results

LncRNA HOXA-AS3 was upregulated in oxLDL-treated HUVECs. In addition, oxLDL-induced growth inhibition of HUVECs was significantly reversed by knockdown of HOXA-AS3. Consistently, oxLDL notably induced G1 arrest in HUVECs, while this phenomenon was greatly reversed by HOXA-AS3 siRNA. Furthermore, downregulation of HOXA-AS3 notably inhibited the progression of atherosclerosis through mediation of miR-455-5p/p27 Kip1 axis. Besides, silencing of HOXA-AS3 notably relieved the symptom of atherosclerosis in vivo.

Conclusion

Downregulation of HOXA-AS3 significantly suppressed the progression of atherosclerosis via regulating miR-455-5p/p27 Kip1 axis. Thus, HOXA-AS3 might serve as a potential target for the treatment of atherosclerosis.