Effect of UV Irradiation (A and C) on Casuarina equisetifolia-Mediated Biosynthesis and Characterization of Antimicrobial and Anticancer Activity of Biocompatible Zinc Oxide Nanoparticles

The green synthesis of nanoparticles has emerged as a simple, safe, sustainable, reliable and eco-friendly protocol. Among different types of NPs, green-synthesized zinc oxide NPs (ZnONPs) show various promising biological uses due to their interesting magnetic, electrical, optical and chemical characteristics. Keeping in view the dependence of the therapeutic efficacy of NPs on their physico-chemical characteristics, the green synthesis of ZnONPs using Casuarina equisetifolia leaf extract under UV-A and UV-C light was carried out in this study. UV-irradiation helped to control the size and morphology of ZnONPs by exciting the electrons in the photoactive compounds of plant extracts to enhance the bio-reduction of ZnO into ZnONPs. C. equisetifolia leaf extract was found enriched with phenolic (2.47 ± 0.12 mg GAE/g DW) and flavonoid content (0.88 ± 0.28 mg QE/g DW) contributing to its 74.33% free-radical scavenging activity. FTIR spectra showed the involvement of polyphenols in the bio-reduction, stabilization and capping of ZnONPs. Moreover, SEM-EDX and XRD analyses showed great potential of UV-C light in yielding smaller (34–39 nm) oval-shaped ZnONPs, whereas UV-A irradiation resulted in the formation of fairly spherical 67–71 nm ZnONPs and control ZnONPs were of mixed shape and even larger size (84–89 nm). Green-synthesized ZnONPs, notably CE-UV-C-ZnONPs, showed promising anti-bacterial activities against Bacillus subtilis, Pseudomonas fluorescens and Pseudomonas aeruginosa. Moreover, ZnONPs also enhanced ROS production which led to a significant loss of mitochondrial membrane potential and activated caspase-3 gene expression and caspase-3/7 activity in human hepatocellular carcinoma (HepG2) cells. CE-UV-C-ZnONP treatment reduced HepG2 cell viability to as low as 36.97% owing to their unique shape and smaller size. Lastly, ZnONPs were found to be highly biocompatible towards brine shrimp and human red blood cells suggesting their bio-safe nature. This research study sheds light on the plausible role of UV radiation in the green synthesis of ZnONPs with reasonable control over their size and morphology, thus improving their biological efficacy.

Design, synthesis, and cytotoxicity screening of new synthesized imidazolidine-2-thiones as VEGFR-2 enzyme inhibitors

A series of imidazolin-2-thione derivatives was synthesized and structurally confirmed through the use of different spectroscopic techniques such as infrared, nuclear magnetic resonance, and mass spectrometry along with elemental analyses. The breast cancer cell line MCF-7 was utilized in the evaluation of the cytotoxic activity of the prepared molecules. The tested molecules 3 and 7 exhibited the best results on MCF-7 cells, with mean IC₅₀ values of 3.26 and 4.31 µM, respectively. The results of the VEGFR-2 assay indicated that compounds 3 and 7 displayed a good inhibition of the VEGFR-2 kinase enzyme. Additionally, DNA flow cytometry of compounds 3 and 7 showed cell cycle arrest at the G0/G1 phase, cell apoptosis, and marked DNA fragmentation in MCF-7 cells. Finally, compounds 3 and 7 were proved to upregulate the activation of effector caspase-3/7, as presented by the caspase-3/7 green flow cytometry assay.

The Influence of Lycopene, [6]-Gingerol, and Silymarin on the Apoptosis on U-118MG Glioblastoma Cells In Vitro Model

BACKGROUND

Lycopene, gingerol, and silymarin have a potential anticancer activity in many types of neoplasms. Healthy lifestyle and proper diet are associated with a reduced risk of cancer and other diseases. Increasingly, clinical research focuses on the mechanisms of action of natural compounds and their impact on the development of cancer. The aim of the present study was to determine the effect of lycopene, gingerol, and silymarin on apoptosis, mitochondrial potential and caspase-3/7 activity in the U118-MG cell line.

METHODS

Human glioblastoma cells were incubated with lycopene, [6]-gingerol, and silymarin for 24 and 48 h. Apoptosis was monitored using the Annexin V labelling, caspase-3/7 activity, and early hallmark of apoptosis were determined with mitochondrial membrane potential changes.

RESULTS

Our data showed a significant decrease in the viability glioblastoma cells U118-MG after 48 h treatment with lycopene, [6]-gingerol, and silymarin.

CONCLUSIONS

Our data could confirm the stimulative effects of used compounds on apoptosis and changes in mitochondrial potential in a dose-dependent manner.

A High Throughput Apoptosis Assay using 3D Cultured Cells

A high throughput apoptosis assay using 3D cultured cells was developed with a micropillar/microwell chip platform. Live cell apoptosis assays based on fluorescence detection have been useful in high content screening. To check the autofluorescence of drugs, controls (no caspase-3/7 reagent in the assay) for the drugs are necessary which require twice the test space. Thus, a high throughput capability and highly miniaturized format for reducing reagent usage are necessary in live cell apoptosis assays. Especially, the expensive caspase-3/7 reagent should be reduced in a high throughput screening system. To solve this issue, we developed a miniaturized apoptosis assay using micropillar/microwell chips for which we tested seventy drugs (six replicates) per chip and reduced the assay volume to 1 µL. This reduced assay volume can decrease the assay costs compared to the 10–40 µL assay volumes used in 384 well plates. In our experiments, among the seventy drugs, four drugs (Cediranib, Cabozatinib, Panobinostat, and Carfilzomib) induced cell death by apoptosis. Those results were confirmed with western blot assays and proved that the chip platform could be used to identify high potency apoptosis-inducing drugs in 3D cultured cells with alginate.

Design, synthesis, and biologic evaluation of novel chrysin derivatives as cytotoxic agents and caspase-3/7 activators

Background

Chrysin (5,7-dihydroxyflavone) is a widely distributed natural flavonoid found in many plant extracts, honey and propolis. Several studies revealed that chrysin possesses multiple biological activities including anti-cancer effects. It has been established that activation of apoptosis is the key molecular mechanism responsible for the cytotoxic potential of chrysin. The objective of this study was to design and synthesize potent chrysin analogues as potential cytotoxic agents.

Methods

A series of chrysin derivatives (3a-m) bearing N'-alkylidene/arylideneacetohydrazide moiety were designed, synthesized, and evaluated for their antiproliferative activity against two human breast cancer cell lines, MDA-MB-231 and MCF-7 by applying the MTT colorimetric assay. Selected compounds were tested for their ability to induce apoptosis through caspase 3/7 activation in MDA-MB-231 cells only since MCF-7 cells lack procaspase 3.

Results

Compounds (3a-m) were obtained as geometrical isomers (E/Z isomers) in good yields upon treatment of hydrazide 5 with different aliphatic and aromatic aldehydes. Most of the synthesized compounds demonstrated moderate-to-good activity against both cell lines. The cytotoxicity results revealed the importance of lipophilic moieties at C-4 position of ring D in imparting the cytotoxic activities to the compounds. Compound 3e with 4-benzyloxy substituent was found to be the most active among the synthesized compounds with IC50 3.3 µM against MDA-MB-231 and 4.2 µM against MCF-7 cell lines. The cytotoxic potential of compound 3e is comparable to that of the well-known anti-cancer agent doxorubicin. In addition, compounds substituted with fluoro (3b), nitro (3h), and dimethylamino (3j) exhibited good cytotoxicity with IC₅₀ <6.5 µM against MDA-MB-231 and <12 µM against MCF-7. Selected compounds were able to induce apoptosis in MDA-MB-231 cells as indicated by caspase-3 and/or -7 activation.

Conclusion

Our results show that the newly designed chrysin derivatives exert anticancer activity in human breast cancer cell lines, MDA-MB-231 and MCF-7. Therefore, they can be considered as leads for further development of more potent and selective cytotoxic agents.

CHSY1 promoted proliferation and suppressed apoptosis in colorectal cancer through regulation of the NFκB and/or caspase-3/7 signaling pathway

Colorectal cancer is a commonly observed malignant cancer. However, the limited therapies for colorectal cancer do not bring much benefit for patients. Chondroitin synthase-1 (CHSY1) is an enzyme responsible for the biosynthesis of chondroitin sulfate and has been implicated in the tumorigenesis of several cancer types; however, there is limited information regarding the role of CHSY1 in colorectal cancer. In the present study, CHSY1 was demonstrated to be highly expressed in colorectal cancer tissues and in cell lines, and the CHSY1 expression level was associated with the 5-year survival rate of patients with colorectal cancer. Following CHSY1 knockdown, the proliferation of colorectal cancer cells was significantly decreased. The number of RKO cells decreased by 50% following CHSY1 knockdown compared with that in the control after culture for 5 days. However, the apoptosis rate of RKO cells increased to 14.15% after CHSY1 knockdown. In addition, the activity of caspase-3/7 was also enhanced. Furthermore, the expression of B-cell lymphoma 2 (Bcl-2) was reduced, whereas the levels of Bcl-2-associated X protein (Bax) and truncated caspase-3/7 were increased following CHSY1 knockdown. Additionally, the phosphorylation level of IκB and the expression of nuclear factor (NF)κB also decreased. In contrast, forced expression of CHSY1 increased the level of Bcl-2, NFκB, and phosphorylated IκB, whereas the level of bax and truncated caspase-3/7 decreased. Therefore, the data of the present study suggest that CHSY1 promoted cell proliferation by regulating NFκB signaling and suppressed cell apoptosis by regulating/caspase-3/7 signaling in colorectal cancer. The present study also suggests that CHSY1 may be a potential target for colorectal cancer therapy.

Clinical implication of UCA1 in non-small cell lung cancer and its effect on caspase-3/7 activation and apoptosis induction in vitro

Since urothelial cancer associated 1 (UCA1) was discovered in human bladder cancer, it has been reported to be dysregulated expressed in various kinds of solid tumors. But the clinical role and the function of UCA1 in non-small cell lung cancer (NSCLC) remains incompletely understood. In this study, we mined the data of UCA1 expression in NSCLC from Oncomine, Gene expression profiling interactive analysis (GEPIA) and cBioPortal to analyze the contribution of UCA1 in the cancer initiation and progression of NSCLC. We also performed a series of in vitro experiments by using NSCLC cells to confirm the biological function of UCA1 in NSCLC, especially its effect on caspase-3/7 activity and apoptosis through RNA interference experiment. From Oncomine, the UCA1 levels were both up-regulated in lung adenocarcinoma (LUAD) and lung squamous carcinoma (LUSC), as compared to non-cancerous controls. Higher levels of UCA1 pointed to a poorer overall survival in NSCLC, with the HR being 1.3. Only two genetic alterations, including amplification and deep deletion, were observed for UCA1 as provided by cBioPortal. Both MTS and Cell Titer-blue assays showed an accordant inhibitory effect of UCA1 siRNAs on the cell growth. In conclusion, lncRNA UCA1 might play a substantial role in the occurrence and development of NSCLC, especially in LUAD patients, which is partly due to its effect on caspase-3/7 activity suppression.

Identification of small-molecule inhibitors of Zika virus infection and induced neural cell death via a drug repurposing screen

In response to the current global health emergency posed by the Zika virus (ZIKV) outbreak and its link to microcephaly and other neurological conditions, we performed a drug repurposing screen of ∼6,000 compounds that included approved drugs, clinical trial drug candidates and pharmacologically active compounds; we identified compounds that either inhibit ZIKV infection or suppress infection-induced caspase-3 activity in different neural cells. A pan-caspase inhibitor, emricasan, inhibited ZIKV-induced increases in caspase-3 activity and protected human cortical neural progenitors in both monolayer and three-dimensional organoid cultures. Ten structurally unrelated inhibitors of cyclin-dependent kinases inhibited ZIKV replication. Niclosamide, a category B anthelmintic drug approved by the US Food and Drug Administration, also inhibited ZIKV replication. Finally, combination treatments using one compound from each category (neuroprotective and antiviral) further increased protection of human neural progenitors and astrocytes from ZIKV-induced cell death. Our results demonstrate the efficacy of this screening strategy and identify lead compounds for anti-ZIKV drug development.

Caspase-3/7-mediated Cleavage of β2-spectrin is Required for Acetaminophen-induced Liver Damage

The ubiquitously expressed β2-spectrin (β2SP, SPTBN1) is the most common non-erythrocytic member of the β-spectrin gene family. Loss of β2-spectrin leads to defects in liver development, and its haploinsufficiency spontaneously leads to chronic liver disease and the eventual development of hepatocellular cancer. However, the specific role of β2-spectrin in liver homeostasis remains to be elucidated. Here, we reported that β2-spectrin was cleaved by caspase-3/7 upon treatment with acetaminophen which is the main cause of acute liver injury. Blockage of β2-spectrin cleavage robustly attenuated β2-spectrin-specific functions, including regulation of the cell cycle, apoptosis, and transcription. Cleaved fragments of β2-spectrin were physiologically active, and the N- and C-terminal fragments retained discrete interaction partners and activity in transcriptional regulation and apoptosis, respectively. Cleavage of β2-spectrin facilitated the redistribution of the resulting fragments under conditions of liver damage induced by acetaminophen. In contrast, downregulation of β2-spectrin led to resistance to acetaminophen-induced cytotoxicity, and its insufficiency in the liver promoted suppression of acetaminophen-induced liver damage and enhancement of liver regeneration. Conclusions: β2-Spectrin, a TGF-β mediator and signaling molecule, is cleaved and activated by caspase-3/7, consequently enhancing apoptosis and transcriptional control to determine cell fate upon liver damage. These findings have extended our knowledge on the spectrum of β2-spectrin functions from a scaffolding protein to a target and transmitter of TGF-β in liver damage.

Preclinical Kinetic Analysis of the Caspase-3/7 PET Tracer 18F-C-SNAT: Quantifying the Changes in Blood Flow and Tumor Retention After Chemotherapy

Early detection of tumor response to therapy is crucial to the timely identification of the most efficacious treatments. We recently developed a novel apoptosis imaging tracer, (18)F-C-SNAT (C-SNAT is caspase-sensitive nanoaggregation tracer), that undergoes an intramolecular cyclization reaction after cleavage by caspase-3/7, a biomarker of apoptosis. This caspase-3/7-dependent reaction leads to an enhanced accumulation and retention of (18)F activity in apoptotic tumors. This study aimed to fully examine in vivo pharmacokinetics of the tracer through PET imaging and kinetic modeling in a preclinical mouse model of tumor response to systemic anticancer chemotherapy.

METHODS

Tumor-bearing nude mice were treated 3 times with intravenous injections of doxorubicin before undergoing a 120-min dynamic (18)F-C-SNAT PET/CT scan. Time-activity curves were extracted from the tumor and selected organs. A 2-tissue-compartment model was fitted to the time-activity curves from tumor and muscle, using the left ventricle of the heart as input function, and the pharmacokinetic rate constants were calculated.

RESULTS

Both tumor uptake (percentage injected dose per gram) and the tumor-to-muscle activity ratio were significantly higher in the treated mice than untreated mice. Pharmacokinetic rate constants calculated by the 2-tissue-compartment model showed a significant increase in delivery and accumulation of the tracer after the systemic chemotherapeutic treatment. Delivery of (18)F-C-SNAT to the tumor tissue, quantified as K1, increased from 0.31 g⋅(mL⋅min)(-1) in untreated mice to 1.03 g⋅(mL⋅min)(-1) in treated mice, a measurement closely related to changes in blood flow. Accumulation of (18)F-C-SNAT, quantified as k3, increased from 0.03 to 0.12 min(-1), proving a higher retention of (18)F-C-SNAT in treated tumors independent from changes in blood flow. An increase in delivery was also found in the muscular tissue of treated mice without increasing accumulation.

CONCLUSION

(18)F-C-SNAT has significantly increased tumor uptake and significantly increased tumor-to-muscle ratio in a preclinical mouse model of tumor therapy. Furthermore, our kinetic modeling of (18)F-C-SNAT shows that chemotherapeutic treatment increased accumulation (k3) in the treated tumors, independent of increased delivery (K1).

Involvement of NF-κB and HSP70 signaling pathways in the apoptosis of MDA-MB-231 cells induced by a prenylated xanthone compound, α-mangostin, from Cratoxylum arborescens

Background

Cratoxylum arborescens has been used traditionally in Malaysia for the treatment of various ailments.

Methods

α-Mangostin (AM) was isolated from C. arborescens and its cell death mechanism was investigated. AM-induced cytotoxicity was observed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Acridine orange/propidium iodide staining and annexin V were used to detect cells in early phases of apoptosis. High-content screening was used to observe the nuclear condensation, cell permeability, mitochondrial membrane potential, and cytochrome c release. The role of caspases-3/7, -8, and -9, reactive oxygen species, Bcl-2 and Bax expression, and cell cycle arrest were also investigated. To determine the role of the central apoptosis-related proteins, a protein array followed by immunoblot analysis was conducted. Moreover, the involvement of nuclear factor-kappa B (NF-κB) was also analyzed.

Results

Apoptosis was confirmed by the apoptotic cells stained with annexin V and increase in chromatin condensation in nucleus. Treatment of cells with AM promoted cell death-transducing signals that reduced MMP by downregulation of Bcl-2 and upregulation of Bax, triggering cytochrome c release from the mitochondria to the cytosol. The released cytochrome c triggered the activation of caspase-9 followed by the executioner caspase-3/7 and then cleaved the PARP protein. Increase of caspase-8 showed the involvement of extrinsic pathway. AM treatment significantly arrested the cells at the S phase (P<0.05) concomitant with an increase in reactive oxygen species. The protein array and Western blotting demonstrated the expression of HSP70. Moreover, AM significantly blocked the induced translocation of NF-κB from cytoplasm to nucleus.

Conclusion

Together, the results demonstrate that the AM isolated from C. arborescens inhibited the proliferation of MDA-MB-231 cells, leading to cell cycle arrest and programmed cell death, which was suggested to occur through both the extrinsic and intrinsic apoptosis pathways with involvement of the NF-κB and HSP70 signaling pathways.

Formaldehyde suppresses neuronal apoptosis via inhibition of outward K(+) currents in rat hippocampus

Formaldehyde (FA) is widely present in the environment, and is also a mammalian metabolite. However, its biological role has not been well understood. Here, we show that FA plays an anti-apoptotic role in cultured hippocampal neurons: FA suppressed staurosporine-induced neuronal apoptosis and inhibited the activity of apoptosis-associated caspase-3/7 proteases in a concentration-dependent manner. Moreover, FA suppressed outward K(+) currents and attenuated the enhanced IK currents that are associated with neuronal apoptosis. As an increase in outward K(+) currents is critical for cell apoptosis, our results suggest that FA exerts its anti-apoptotic effects on neuronal cells, probably through its inhibitory effect on the outward K(+) currents.