Caspase-8 and Caspase-9 Functioned Differently at Different Stages of the Cyclic Stretch-Induced Apoptosis in Human Periodontal Ligament Cells

The anti-obesity effects of resveratrol on the 3T3-L1 adipocytes

Obesity is a severe health problem worldwide due to its association with various adverse health consequences. The present study aims to evaluate the anti-obesity effects of resveratrol, as a natural polyphenol, on the 3T3-L1 adipocytes. PubMed, Scopus, ScienceDirect, Web of Sciences, and Google Scholar databases were searched up to March 2022 using relevant keywords. All original articles, written in English, evaluating the anti-obesity effects of resveratrol on the 3T3-L1 adipocytes were eligible for this review. Initially, 4361 records were found in the electronic search databases. After removing duplicates and irrelevant studies according to the title and abstract, the full text of the 51 articles was critically screened and 38 in vitro studies were included in this review. Except for one case, all of these studies reported that different doses (ranged 1-200 μM) of resveratrol treatment have anti-obesity effects on 3T3L1 adipocytes through various mechanisms such as induction of apoptosis, a decrease of fat accumulation and adipogenesis, promotion of white adipocytes browning, inhibition of preadipocyte proliferation and consequent differentiation, and up-regulation of miRNA that involved in the antiadipogenic and triacylglycerol metabolism in white adipose tissue. The findings indicate that resveratrol has anti-obesity effects. Therefore, resveratrol treatment could be used to prevent and treat obesity and its related disorders. Well-designed randomized clinical trials with different doses of resveratrol are recommended to be performed on obese subjects.

Tannic Acid Impedes the Proliferation of Bladder Cancer Cells by Elevating Mitochondrial Pathways of Apoptosis

Bladder cancer stands as a prevailing neoplasm among men globally, distinguished for its pronounced malignancy attributed to invasiveness and metastatic proclivity. Tannic acid (TA), an organic compound in many plants, has garnered recent attention for its discernible anti-mutagenic attributes. This investigation endeavored to scrutinize the repercussions of TA on grade II bladder cancer, with a concerted focus on unraveling its anti-cancer mechanisms. The cytotoxic effects of TA on grade II bladder cancer cells were investigated using multiple techniques, including MTT assay, flow cytometry, TUNEL assay, and western blot. Our findings revealed that elevated concentrations of TA induced cytotoxic effects in grade II bladder cancer cells. Both flow cytometry and the TUNEL assay substantiated the dose-dependent capacity of TA to prompt apoptosis. Western blot analysis corroborated that TA treatment in bladder cancer cells resulted in the upregulation of cleaved caspase-3 expression and PARP. Furthermore, heightened TA dosage elicited an augmentation in the expression of pro-apoptotic proteins, namely Bax and Bak, alongside a reduction in the expression of the anti-apoptotic protein Bcl-2 within bladder cancer cells. This study confirms TA as a potential anticancer agent, demonstrably diminishing the viability of bladder cancer cells. TA exerts cytotoxicity through the activation of mitochondrial apoptotic pathways. Specifically, TA initiates the cleavage of PARP and caspase-3, concurrently augmenting the expression of pro-apoptotic proteins to facilitate apoptosis. Collectively, the present study indicates that TA effectively impedes the proliferation of bladder cancer cells by instigating apoptosis through the intrinsic mitochondrial pathway.

Caspase-mediated processing of TRBP regulates apoptosis during viral infection

RNA silencing is a post-transcriptional gene-silencing mechanism mediated by microRNAs (miRNAs). However, the regulatory mechanism of RNA silencing during viral infection is unclear. TAR RNA-binding protein (TRBP) is an enhancer of RNA silencing that induces miRNA maturation by interacting with the ribonuclease Dicer. TRBP interacts with a virus sensor protein, laboratory of genetics and physiology 2 (LGP2), in the early stage of viral infection of human cells. Next, it induces apoptosis by inhibiting the maturation of miRNAs, thereby upregulating the expression of apoptosis regulatory genes. In this study, we show that TRBP undergoes a functional conversion in the late stage of viral infection. Viral infection resulted in the activation of caspases that proteolytically processed TRBP into two fragments. The N-terminal fragment did not interact with Dicer but interacted with type I interferon (IFN) signaling modulators, such as protein kinase R (PKR) and LGP2, and induced ER stress. The end results were irreversible apoptosis and suppression of IFN signaling. Our results demonstrate that the processing of TRBP enhances apoptosis, reducing IFN signaling during viral infection.

Lemon Peel Water Extract: A Novel Material for Retinal Health, Protecting Retinal Pigment Epithelial Cells against Dynamin-Related Protein 1-Mediated Mitochondrial Fission by Blocking ROS-Stimulated Mitogen-Activated Protein Kinase/Extracellular Signal-Regulated Kinase Pathway

Previous studies showed that NaIO3 can induce oxidative stress-mediated retinal pigment epithelium (RPE) damage to simulate age-related macular degeneration (AMD). Lemon peel is rich in antioxidants and components that can penetrate the blood-retinal barrier, but their role in retinal oxidative damage remains unexplored. Here, we explore the protection of lemon peel ultrasonic-assisted water extract (LUWE), containing large amounts of flavonoids and polyphenols, against NaIO3-induced retinal degeneration. We initially demonstrated that LUWE, orally administered, prevented retinal distortion and thinning on the inner and outer nuclei layers, downregulating cleaved caspase-3 protein expression in RPE cells in NaIO3-induced mice. The effect of LUWE was achieved through the suppression of apoptosis and the associated proteins, such as cleaved PARP and cleaved caspase-3, as suggested by NaIO3-induced ARPE-19 cell models. This is because LUWE reduced reactive oxygen species-mediated mitochondrial fission via regulating p-Drp-1 and Fis1 expression. We further confirmed that LUWE suppresses the expression of p-MEK-1/2 and p-ERK-1/2 in NaIO3-induced ARPE-19 cells, thereby providing the protection described above, which was confirmed using PD98059 and U0126. These results indicated that LUWE prevents mitochondrial oxidative stress-mediated RPE damage via the MEK/ERK pathway. Elucidation of the molecular mechanism may provide a new protective strategy against retinal degeneration.

Discovery of a stilbenoid-flavanone hybrid as an antitumor Wnt/β-catenin signaling pathway inhibitor

A series of designed stilbenoid-flavanone hybrids featuring sp3-hybridized C2 and C3 atoms of C-ring was evaluated against colorectal cancers presented compounds 4, 17, and 20 as the most potential compounds among explored compounds. Evaluation of the anticancer activity spectrum of compounds 4, 17, and 20 against diverse solid tumors presented compounds 17 and 20 with interesting anticancer spectrum. The potencies of compounds 17 and 20 were assessed in comparison with FDA-approved anticancer drugs. Compound 17 was the, in general, the most potent showing low micromolar GI50 values that were more potent than the standard FDA-approved drugs against several solid tumors including colon, brain, skin, renal, prostate and breast tumors. Compound 17 was subjected for evaluation against normal cell lines and was subjected to a mechanism study in HCT116 colon cancer cells which presented it as an inhibitor of Wnt signaling pathway triggering G2/M cell cycle arrest though activation of p53-p21 pathway as well as intrinsic and extrinsic apoptotic death of colon cancer cells. Compound 17 might be a candidate for further development against diverse solid tumors including colon cancer.

The Simultaneous Effects of miR-145-5p and hsa-let-7a-3p on Colorectal Tumorigenesis: In Vitro Evidence

Purpose

MicroRNAs (miRNAs) are a group of small regulatory non-coding RNAs, which are dysregulated through tumor progression. let-7 and MIR-145 are both tumor suppressor microRNAs that are downregulated in a wide array of cancers including colorectal cancer (CRC).

Methods

This study was aimed to investigate the effect of simultaneous replacement of these two tumor suppressor miRNAs on proliferation, apoptosis, and migration of CRC cells. HCT-116 with lower expression levels of hsa-let-7a-3p and MIR-145-5p was selected for functional investigations. The cells were cultured and transfected with hsa-let-7a and MIR-145, separately and in combination. Cell viability and apoptosis rates were assessed by MTT assay and flow cytometry, respectively. Cell cycle status was further evaluated using flow cytometry and qRT-PCR was employed to evaluate gene expression.

Results

The obtained results showed that exogenous overexpression of MIR-145 and hsa-let-7a in HCT-116 cells could cooperatively decrease CRC cell proliferation and induce sub-G1 cell cycle arrest. Moreover, hsa-let-7a and MIR-145 co-transfection significantly increased apoptosis induction compared to separate transfected cells and control through modulating the expression levels of apoptosis-related genes including Bax, Bcl-2, P53, Caspase-3, Caspase-8, and Caspase-9. Furthermore, qRT-PCR results illustrated that hsa-let-7a and MIR-145 combination more effectively downregulated MMP-9 and MMP-2 expression, as the important modulators of metastasis, compared to the controls.

Conclusion

Taken together, considering that exogenous overexpression of MIR-145 and hsa-let-7a showed cooperative anti-cancer effects on CRC cells, their combination may be considered as a novel therapeutic strategy for the treatment of CRC.

Morphologically different hydroxyapatite nanoparticles exert differential genotoxic effects in Drosophila

Hydroxyapatite (HAP) occurs naturally in sedimentary and metamorphic rocks and constitutes the hard structures in many organisms. Since synthetic nano-sized HAP (HAP-NPs) are used in orthopedic applications and for heavy metal remediation in aquatic and terrestrial media, both environment and humans are exposed to them. Due to the concerns about their potential hazards, the genotoxic effects that round/rod forms of HAP-NPs were investigated in Drosophila using the wing-spot and the comet assays. Furthermore, caspase activities were evaluated to examine the activation of cell death pathways. As a novelty, the expression of 36 genes involved in DNA repair was investigated, as a tool to indirectly determine DNA damage induction. Obtained sizes were 35-60 nm (roundHAP-NPs) and 45-90 nm (rodHAP-NPs) with a low Zeta-potential (-1.65 and 0.37 mV, respectively). Genotoxicity was detected in the wing-spot (round form), and in the comet assay (round and rod-like HA-NPs). In addition, increased expression of Caspases 3/7, 8, and 9 activities were observed. For both HAP forms, increased changes in the expression were observed for mismatch repair genes, while decreased expression was observed for genes involved in ATM, ATR, and cell cycle pathways. The observed changes in the repair pathways would reinforce the view that HAP-NPs have genotoxic potential, although more markedly in the round form. Thus, the environmental presence of engineered nanoparticles, including HAPs, raises concerns about potential effects on human health. It is essential that the effects of their use are carefully assessed and monitored to ensure safety and to mitigate any potential adverse effects.

Current trends in luminescence-based assessment of apoptosis

Apoptosis, the most extensively studied type of cell death, is known to play a crucial role in numerous processes such as elimination of unwanted cells or cellular debris, growth, control of the immune system, and prevention of malignancies. Defective regulation of apoptosis can trigger various diseases and disorders including cancer, neurological conditions, autoimmune diseases and developmental disorders. Knowing the nuances of the cell death type induced by a compound can help decipher which therapy is more effective for specific diseases. The detection of apoptotic cells using classic methods has brought significant contribution over the years, but innovative methods are quickly emerging and allow more in-depth understanding of the mechanisms, aside from a simple quantification. Due to increased sensitivity, time efficiency, pathway specificity and negligible cytotoxicity, these innovative approaches have great potential for both in vitro and in vivo studies. This review aims to shed light on the importance of developing and using novel nanoscale methods as an alternative to the classic apoptosis detection techniques.

Tumor-targeted liposomes with platycodin D2 promote apoptosis in colorectal cancer

Conventional chemotherapy for colorectal cancer (CRC), though efficacious, is discouraging due to its limited targeting capability, lack of selectivity, and chemotherapy-associated side effects. With the advent of nanomedicines, a liposomal delivery system making use of a combination of anticancer phytochemicals is fast gaining popularity as one of the most promising nanoplatforms for CRC treatment. Rising evidence supports phytochemicals such as platycosides for their anticancer potency. To this end, a combination therapy including tumor-targeted liposomes along with phytochemicals might have a greater therapeutic potential against cancer. In this study, we developed acidity-triggered rational membrane (ATRAM) along with conjugated platycodin D2 (PCD2) and liposomes (PCD2-Lipo-ATRAM) as a tumor-targeting therapy. The PCD2-Lipo-ATRAM treatment demonstrated a successful tumor-targeting ability in the CRC xenografts, in which PCD2 not only exerted a potent antitumor effect by inducing apoptotic cell death and but also functioned as a liposome membrane stabilizer. Moreover, PCD2-Lipo-ATRAM suppressed antiapoptotic BCL-2 family proteins, resulting in enhanced cytotoxicity toward CRC cells by inducing intrinsic caspase-9/-3 mediated apoptosis. Thus, our data has shown that tumor-targeting PCD2-based liposomal systems represent a promising strategy for CRC therapy, since they directly target the tumors, unlike other therapies that can miss the target.

Exosomes from Cyclic Stretched Periodontal Ligament Cells Induced Periodontal Inflammation through miR-9-5p/SIRT1/NF-κB Signaling Pathway

Abundant evidence demonstrates that mechanical stress could induce an inflammatory response in periodontal tissue, but the precise mechanism remains unclear. In the past few years, periodontal ligament cells (PDLCs), as the most force-sensitive cells, have been investigated in depth as local immune cells, associated with activation of inflammasomes and secretion of inflammatory cytokines in response to mechanical stimuli. However, this study innovatively inspected the effect of PDLCs on the other immune cells after stretch loading to reveal the detailed mechanism by which mechanical stimuli initiate immunoreaction in periodontium. In the present study, we found that cyclic stretch could stimulate human PDLCs to secret exosomes and that these exosomes could further induce the increase of phagocytic cells in the periodontium in Sprague-Dawley rats and the M1 polarization of the cultured macrophages (including the mouse macrophage cell line RAW264.7 and the bone marrow-derived macrophages from C57BL/6 mice). Furthermore, the exosomal miR-9-5p was detected to be overexpressed after mechanical stimuli in both in vivo and in vitro experiments and could trigger M1 polarization via the SIRT1/NF-κB signaling pathway in the cultured macrophages. In summary, this study revealed that PDLCs could transmit the mechanobiological signals to immune cells by releasing exosomes and simultaneously enhance periodontal inflammation through the miR-9-5p/SIRT1/NF-κB pathway. We hope that our research can improve understanding of force-related periodontal inflammatory diseases and lead to new targets for treatment.

Ruellia tuberosa Ethyl Acetate Leaf Extract Induces Apoptosis and Cell Cycle Arrest in Human Breast Cancer Cell Line, MCF-7

Ruellia tuberosa L. has been previously shown to possess antioxidant and antiproliferative activities on cancer cells but its underlying mechanisms are largely unknown. This study aimed to elucidate the mode of action underlying this inhibitory effect on MCF-7 using ethyl acetate extract obtained after liquid-liquid partition of methanol crude extract. Antiproliferative effect of R. tuberosa ethyl acetate leaf extract (RTEAL) was evaluated using MTT assay. Its ability to induce apoptosis was assessed by DNA ladder formation, JC-1, Annexin V, and methylene blue staining assays. Perturbation of cell cycle progression was determined using flow cytometry. RTEAL was found to selectively inhibit the proliferation of MCF-7 cells with the IC50 value of 28 µg/mL. Morphological changes such as nuclear fragmentation and chromatin condensation were observed although DNA laddering was undetected in agarose gel. RTEAL-induced apoptotic pathways by inhibiting the expression of anti-apoptotic BCL-2 while upregulating pro-apoptotic BAX, caspase 7 and caspase 8. RTEAL also caused cell cycle arrests at the S and G2/M phase and dysregulation of cell cycle regulators. These findings collectively demonstrate that RTEAL extract inhibited cell growth by inducing apoptosis and cell cycle arrest, suggesting its therapeutic potential against breast cancer.

Influence of Inhibition of COX-2-Dependent Lipid Metabolism on Regulation of UVB-Induced Keratinocytes Apoptosis by Cannabinoids

Inflammation and apoptosis are regulated by similar factors, including ultraviolet B (UVB) radiation and cannabinoids, which are metabolized by cyclooxygenase-2 (COX-2) into pro-apoptotic prostaglandin derivatives. Thus, the aim of this study was to evaluate the impact of cyclooxygenase-2 inhibition by celecoxib on the apoptosis of keratinocytes modulated by UVB, anandamide (AEA) and cannabidiol (CBD). For this purpose, keratinocytes were non-treated/treated with celecoxib and/or with UVB and CBD and AEA. Apoptosis was evaluated using microscopy, gene expressions using quantitate reverse-transcriptase polymerase chain reaction; prostaglandins using liquid chromatography tandem mass spectrometry and cyclooxygenase activity using spectrophotometry. UVB enhances the percentage of apoptotic keratinocytes, which can be caused by the increased prostaglandin generation by cyclooxygenase-2, or/and induced cannabinoid receptor 1/2 (CB1/2) expression. AEA used alone intensifies apoptosis by affecting caspase expression, and in UVB-irradiated keratinocytes, cyclooxygenase-2 activity is increased, while CBD acts as a cytoprotective when used with or without UVB. After COX-2 inhibition, UVB-induced changes are partially ameliorated, when anandamide becomes an anti-apoptotic agent. It can be caused by observed reduced generation of anandamide pro-apoptotic derivative prostaglandin-ethanolamide by COX. Therefore, products of cyclooxygenase-dependent lipid metabolism seem to play an important role in the modulation of UVB-induced apoptosis by cannabinoids, which is particularly significant in case of AEA as inhibition of cyclooxygenase reduces the generation of pro-apoptotic lipid mediators and thus prevents apoptosis.

In silico and in vitro studies on the anti-cancer activity of artemetin, vitexicarpin and penduletin compounds from Vitex negundo

Vitex negundo L. (V. negundo) is one of the important medicinal and anticancer enhancer herbs. This plant is commonly used in the preparation of traditional drugs to treat numerous diseases. Inspired by the medicinal properties of this plant, the current study aimed to investigate antiproliferative potential and the primary molecular mechanisms of the apoptotic induction against human HepG2 and MCF-7 cell lines, by pure compounds isolated from targeted fractions of V. negundo which were characterized by NMR, FTIR and HRMS analysis and identified as artemetin (FLV1), vitexicarpin (FLV2), and penduletin (FLV3) compounds. The FLV1, FLV2, and FLV3 compounds were evaluated for the antiproliferative potential against HepG2 and MCF-7 cell lines by cell viability assay and exhibited IC₅₀ values of 2.3, 23.9 and 5.6 µM and 3.9, 25.8, and 6.4 µM, respectively. In addition, those compounds increased the level of reactive oxygen species production, induced cell death occurred via apoptosis, demonstrated by Annexin V-staining cells, contributed significantly to DNA damage, and led to the activation of caspase3/caspase8 pathways.Additionally, molecular docking was also conducted to rationalize the cancer cells inhibitory and to evaluate the ability of the FLV1, FLV2, and FLV3 compounds to be developed as good drug candidates for cancers treatment.

Chemical and Biological Characterization of the Anticancer Potency of Salvia fruticosa in a Model of Human Malignant Melanoma

Malignant melanoma is one of the most aggressive types of skin cancer with an increasing incidence worldwide. Thus, the development of innovative therapeutic approaches is of great importance. Salvia fruticosa (SF) is known for its anticancer properties and in this context, we aimed to investigate its potential anti-melanoma activity in an in vitro model of human malignant melanoma. Cytotoxicity was assessed through a colorimetric-based sulforhodamine-B (SRB) assay in primary malignant melanoma (A375), non-malignant melanoma epidermoid carcinoma (A431) and non-tumorigenic melanocyte neighbouring keratinocyte (HaCaT) cells. Among eight (8) different fractions of S. fruticosa extracts (SF1-SF8) tested, SF3 was found to possess significant cytotoxic activity against A375 cells, while A431 and HaCaT cells remained relatively resistant or exerted no cytotoxicity, respectively. In addition, the total phenolic (Folin-Ciocalteu assay) and total flavonoid content of SF extracts was estimated, whereas the antioxidant capacity was measured via the inhibition of tert-butyl hydroperoxide-induced lipid peroxidation and protein oxidation levels. Finally, apoptotic cell death was assessed by utilizing a commercially available kit for the activation of caspases - 3, - 8 and - 9. In conclusion, the anti-melanoma properties of SF3 involve the induction of both extrinsic and intrinsic apoptotic pathway(s), as evidenced by the increased activity levels of caspases - 8, and - 9, respectively.

IAP and HDAC inhibitors interact synergistically in myeloma cells through noncanonical NF-κB- and caspase-8-dependent mechanisms

Interactions between the inhibitor of apoptosis protein antagonist LCL161 and the histone deacetylase inhibitor panobinostat (LBH589) were examined in human multiple myeloma (MM) cells. LCL161 and panobinostat interacted synergistically to induce apoptosis in diverse MM cell lines, including those resistant to bortezomib (PS-R). Similar interactions were observed with other histone deacetylase inhibitors (MS-275) or inhibitors of apoptosis protein antagonists (birinapant). These events were associated with downregulation of the noncanonical (but not the canonical) NF-κB pathway and activation of the extrinsic, caspase-8-related apoptotic cascade. Coexposure of MM cells to LCL161/LBH589 induced TRAF3 upregulation and led to TRAF2 and NIK downregulation, diminished expression of BCL-XL, and induction of γH2A.X. Ectopic expression of TRAF2, NIK, or BCL-XL, or short hairpin RNA TRAF3 knock-down, significantly reduced LCL161/LBH589 lethality, as did ectopic expression of dominant-negative FADD. Stromal/microenvironmental factors failed to diminish LCL161/LBH589-induced cell death. The LCL161/LBH589 regimen significantly increased cell killing in primary CD138+ cells (N = 31) and was particularly effective in diminishing the primitive progenitor cell-enriched CD138-/19+/20+/27+ population (N = 23) but was nontoxic to normal CD34+ cells. Finally, combined LCL161/LBH589 treatment significantly increased survival compared with single-agent treatment in an immunocompetent 5TGM1 murine MM model. Together, these findings argue that LCL161 interacts synergistically with LBH589 in MM cells through a process involving inactivation of the noncanonical NF-κB pathway and activation of the extrinsic apoptotic pathway, upregulation of TRAF3, and downregulation of TRAF2/BCL-XL. Notably, this regimen overcomes various forms of resistance, is active against primary MM cells, and displays significant in vivo activity. This strategy warrants further consideration in MM.

Disease-Dependent Antiapoptotic Effects of Cannabidiol for Keratinocytes Observed upon UV Irradiation

Although apoptosis of keratinocytes has been relatively well studied, there is a lack of information comparing potentially proapoptotic treatments for healthy and diseased skin cells. Psoriasis is a chronic autoimmune-mediated skin disease manifested by patches of hyperproliferative keratinocytes that do not undergo apoptosis. UVB phototherapy is commonly used to treat psoriasis, although this has undesirable side effects, and is often combined with anti-inflammatory compounds. The aim of this study was to analyze if cannabidiol (CBD), a phytocannabinoid that has anti-inflammatory and antioxidant properties, may modify the proapoptotic effects of UVB irradiation in vitro by influencing apoptotic signaling pathways in donor psoriatic and healthy human keratinocytes obtained from the skin of five volunteers in each group. While CBD alone did not have any major effects on keratinocytes, the UVB treatment activated the extrinsic apoptotic pathway, with enhanced caspase 8 expression in both healthy and psoriatic keratinocytes. However, endoplasmic reticulum (ER) stress, characterized by increased expression of caspase 2, was observed in psoriatic cells after UVB irradiation. Furthermore, decreased p-AKT expression combined with increased 15-d-PGJ₂ level and p-p38 expression was observed in psoriatic keratinocytes, which may promote both apoptosis and necrosis. Application of CBD partially attenuated these effects of UVB irradiation both in healthy and psoriatic keratinocytes, reducing the levels of 15-d-PGJ₂, p-p38 and caspase 8 while increasing Bcl2 expression. However, CBD increased p-AKT only in UVB-treated healthy cells. Therefore, the reduction of apoptotic signaling pathways by CBD, observed mainly in healthy keratinocytes, suggests the need for further research into the possible beneficial effects of CBD.

Iso-suillin-induced DNA damage leading to cell cycle arrest and apoptosis arised from p53 phosphorylation in A549 cells

Extensive investigations have revealed that iso-suillin, a secondary metabolite isolated from Suillus flavus, could induce cell cycle arrest and apoptosis in human chronic myeloid leukemia K562 cells, human hepatocellular carcinoma SMMC-7721 cell line, and human small cell lung cancer H446 cell line in vitro. In the present study, human lung cancer A549 cells were used to reveal the mechanism of iso-suillin's effects on lung adenocarcinoma, which were detected both in vitro and in vivo. Results showed that iso-suillin potently inhibited A549 cell proliferation through an early G₁ arrest. Iso-suillin also induced A549 cell apoptosis in vitro. Phosphorylation of p53 at serines 15 and 20 may be one of the pivotal factors for cell cycle arrest and apoptosis after treatment of iso-suillin in A549 cells. Moreover, in an A549 xenograft model, tumor growth and progression could be inhibited by iso-suillin. Body weight change and some vital organs toxicity was also roughly examined, no significant toxic effects of iso-suillin were shown (at a dose of 5 mg/kg for each administration). The in vitro and in vivo anti-tumor effects implied that iso-suillin may act as a tumor growth inhibitor, and its induction of p53 phosphorylation is pivotal for cell cycle arrest and apoptosis in A549 cells.

Carboplatin and epigallocatechin-3-gallate synergistically induce cytotoxic effects in esophageal cancer cells

Background and purpose:

We aimed at evaluating the effects of combinatorial treatments with carboplatin and epigallocatechin-3-gallate (EGCG) on the KYSE-30 esophageal cancer (EC) cell line and elucidate the underlying mechanisms.

Experimental approach:

EC cells were harvested and exposed to increasing concentrations of carboplatin and EGCG to construct a dose-response plot. Cell inhibitory effects were assessed by the MTT method and apoptosis-related gene expression levels (caspases 8 and 9) and Bcl-2 mRNA were detected using real-time polymerase chain reaction. The lactate levels in the various treated cases were analyzed using the colorimetric assay kit. In addition, total antioxidant capacity was measured.

Findings/Results:

The results indicated that, following treatments with carboplatin in IC₂₀, IC₂₅, and IC₁₀ concentrations when combined with EGCG in similar concentrations, synergistically decreased cell viability versus single treatments of both agents. Also, in combined treatments at IC₂₀ and IC₂₅ of both agents the gene expression ratio of caspases 8 and 9 upregulated significantly compared to monotherapies (P < 0.05). Bcl-2 gene expression ratios were decreased in double agents treated cells versus monotherapies. Following treatment of KYSE-30 cells with carboplatin and EGCG in double combinations, lactate levels were significantly decreased compared with the untreated cells and single treatments (P < 0.05). Also, in IC₂₅, IC₂₀, and IC₁₀ concentrations of both agents the total antioxidant capacity levels were decreased versus monotherapies and untreated cells.

Conclusion and implications:

The presented study determined that treatment with carboplatin and EGCG was capable of promoting cytotoxicity in EC cells and inhibits the cancer progress. Combined treatments with low concentrations of carboplatin and EGCG may promote apoptosis induction and inhibit cell growth. These results confirmed the anticancer effects of carboplatin and EGCG and providing a base for additional use of EGCG to the EC treatment.

The TSPO Ligands MGV-1 and 2-Cl-MGV-1 Differentially Inhibit the Cigarette Smoke-Induced Cytotoxicity to H1299 Lung Cancer Cells

Simple Summary

In this study, we investigated the impact of CS on various TSPO-related mitochondrial processes, and the protective ability of our novel TSPO ligands against such CS-induced cellular damages. Our results support the previously reported role of TSPO in apoptotic cell death. Moreover, the present data demonstrate the protective effect of our TSPO ligands against CS-induced cellular damage.

Abstract

TSPO is involved in cigarette smoke (CS)-induced cellular toxicity, which may result in oral and pulmonary diseases and lung cancer. H1299 lung cancer cells were exposed directly to CS. The H1299 cells were pretreated with our TSPO ligands MGV-1 and 2-Cl-MGV-1 (Ki = 825 nM for both) at a concentration of 25 µM 24 h prior to CS exposure. Cell death and apoptotic markers were measured, in addition to TSPO expression levels, ATP synthase activity, generation of reactive oxygen species (ROS), depolarization of mitochondrial membrane potential (ΔΨm), cAMP and LDH levels. Pretreatment with MGV-1 and 2-Cl-MGV-1 (25 µM), 24 h prior to CS exposure, differentially attenuated the CS-induced cellular insult as well as cell death in H1299 lung cancer cells. These protective effects included prevention of ATP synthase reversal, ROS generation, depolarization of the mitochondrial membrane and elevation in LDH. The preventive efficacy of 2-Cl-MGV-1 was superior to that achieved by MGV-1. Both ligands did not prevent the elevation in cAMP. These findings may indicate a mild protective effect of these TSPO ligands in CS-related pulmonary and keratinocyte cellular pathology.

Regulation of Anti-Apoptotic SOD2 and BIRC3 in Periodontal Cells and Tissues

The aim of the study was to clarify whether orthodontic forces and periodontitis interact with respect to the anti-apoptotic molecules superoxide dismutase 2 (SOD2) and baculoviral IAP repeat-containing protein 3 (BIRC3). SOD2, BIRC3, and the apoptotic markers caspases 3 (CASP3) and 9 (CASP9) were analyzed in gingiva from periodontally healthy and periodontitis subjects by real-time PCR and immunohistochemistry. SOD2 and BIRC3 were also studied in gingiva from rats with experimental periodontitis and/or orthodontic tooth movement. Additionally, SOD2 and BIRC3 levels were examined in human periodontal fibroblasts incubated with Fusobacterium nucleatum and/or subjected to mechanical forces. Gingiva from periodontitis patients showed significantly higher SOD2, BIRC3, CASP3, and CASP9 levels than periodontally healthy gingiva. SOD2 and BIRC3 expressions were also significantly increased in the gingiva from rats with experimental periodontitis, but the upregulation of both molecules was significantly diminished in the concomitant presence of orthodontic tooth movement. In vitro, SOD2 and BIRC3 levels were significantly increased by F. nucleatum, but this stimulatory effect was also significantly inhibited by mechanical forces. Our study suggests that SOD2 and BIRC3 are produced in periodontal infection as a protective mechanism against exaggerated apoptosis. In the concomitant presence of orthodontic forces, this protective anti-apoptotic mechanism may get lost.

Rutin-protected BisGMA-induced cytotoxicity, genotoxicity, and apoptosis in macrophages through the reduction of the mitochondrial apoptotic pathway and induction of antioxidant enzymes

Bisphenol-A-glycidyldimethacrylate (BisGMA) is a resin monomer frequently used in dentin restorative treatments. The leakage of BisGMA monomer from BisGMA-based polymeric resins can lead to cytotoxicity in macrophages. Rutin has various beneficial bioeffects, including antioxidation and antiinflammation. In this study, we found that pretreatment of RAW264.7 macrophages with rutin-inhibited cytotoxicity induced by BisGMA in a concentration-dependent manner. BisGMA-induced apoptosis, which was detected by levels of phosphatidylserine from the internal to the external membrane and formation of sub-G1, and genotoxicity, which was detected by cytokinesis-blocked micronucleus and single-cell gel electrophoresis assays, were inhibited by rutin in a concentration-dependent manner. Rutin suppressed the BisGMA-induced activation of caspase-3 and -9 rather than caspase-8. Rutin inhibited the activation of the mitochondrial apoptotic pathway, including cytochrome C release and mitochondria disruption, after macrophages were treated with BisGMA. Finally, BisGMA-induced reactive oxygen species (ROS) generation and antioxidant enzyme (AOE) deactivation could be reversed by rutin. Parallel trends were observed in the elevation of AOE activation and inhibition of ROS generation, caspase-3 activity, mitochondrial apoptotic pathway activation, and genotoxicity. These results suggested that rutin suppressed BisGMA-induced cytotoxicity through genotoxicity, the mitochondrial apoptotic pathway, and relatively upstream factors, including reduction of ROS generation and induction of AOE.

Mechanical Regulation of Apoptosis in the Cardiovascular System

Apoptosis is a highly conserved physiological process of programmed cell death which is critical for proper organism development, tissue maintenance, and overall organism homeostasis. Proper regulation of cell removal is crucial, as both excessive and reduced apoptotic rates can lead to the onset of a variety of diseases. Apoptosis can be induced in cells in response to biochemical, electrical, and mechanical stimuli. Here, we review literature on specific mechanical stimuli that regulate apoptosis and the current understanding of how mechanotransduction plays a role in apoptotic signaling. We focus on how insufficient or excessive mechanical forces may induce apoptosis in the cardiovascular system and thus contribute to cardiovascular disease. Although studies have demonstrated that a broad range of mechanical stimuli initiate and/or potentiate apoptosis, they are predominantly correlative, and no mechanisms have been established. In this review, we attempt to establish a unifying mechanism for how various mechanical stimuli initiate a single cellular response, i.e. apoptosis. We hypothesize that the cytoskeleton plays a central role in this process as it does in determining myriad cell behaviors in response to mechanical inputs. We also describe potential approaches of using mechanomedicines to treat various diseases by altering apoptotic rates in specific cells. The goal of this review is to summarize the current state of the mechanobiology field and suggest potential avenues where future research can explore.

Anticancer effects and the mechanism underlying 2-methoxyestradiol in human osteosarcoma in vitro and in vivo

Osteosarcoma (OS) occurs in both children and adolescents and leads to a poor prognosis. 2-methoxyestradiol (2-ME) has a strong antitumor effect and is effective against numerous types of tumor. However, 2-ME has a low level of antitumor effects in OS. The present study investigated the effects of 2-ME on the proliferation and apoptosis of human MG63 OS cells. The potential biological mechanisms by which 2-ME exerts its biological effects were also investigated in the present study. The results of the present study demonstrated that 2-ME inhibited the proliferation of OS cells in a time- and dose-dependent manner, induced G₂/M phase cell cycle arrest and early apoptosis. The expression levels of vascular endothelial growth factor (VEGF), Bcl-2 and caspase-3 were measured via western blotting and reverse transcription-quantitative PCR. As the concentration of 2-ME increased, the RNA and protein expression levels of VEGF and Bcl-2 decreased gradually, whereas the expression of caspase-3 increased gradually. In addition, tumor growth in nude mice was suppressed by 2-ME with no toxic side effects observed in the liver or kidney. Immunohistochemistry demonstrated that the expression levels of Bcl-2 and VEGF were significantly lower, and those of caspase-3 were significantly higher in test mice compared with the control group. TUNEL staining of xenograft tumors revealed that with increased 2-ME concentration, the number of apoptotic cells also gradually increased. Thus, 2-ME effectively inhibited the proliferation and induced apoptosis of MG63 OS cells in vitro and in vivo with no obvious side effects. The mechanism of the anticancer effect of 2-ME may be associated with the actions of Bcl-2, VEGF and caspase-3.

ARHGAP17 inhibits pathological cyclic strain-induced apoptosis in human periodontal ligament fibroblasts via Rac1/Cdc42

Rho GTPase-activating protein (Rho-GAP) and Rho GDP dissociation inhibitor (Rho- GDI) are two main negative regulators of Rho GTPase. Our previous work has found that Rho-GDI and Rho GTPase are involved in the response of human periodontal ligament (PDL) cells to mechanical stress. However, whether Rho-GAP also has a role in this process remains unknown. Here, we attempted to find the Rho-GAP gene that may be involved in pathological stretch-induced apoptosis of PDL cells. Human PDL fibroblasts were exposed to 20% cyclic strain for 6 hours or 24 hours, after which the expression levels of ARHGAP10, ARHGAP17, ARHGAP21, ARHGAP24 and ARHGAP28 were determined. Results showed that ARHGAP17 expression decreased the most obviously after treatment of stretch. In addition, ARHGAP17 overexpression abolished 20% cyclic strain-induced apoptosis. Therefore, ARHGAP17 has an important role in pathological stretch-induced apoptosis of human PDL fibroblasts. Moreover, we found that ARHGAP17 overexpression also alleviated cyclic strain-induced activation of Rac1/Cdc42, a major downstream target of ARHGAP17. Furthermore, two Rac1 inhibitors, NSC23766 and EHT 1864, both attenuated ARHGAP17 knockdown-mediated apoptosis in human PDL fibroblasts. Collectively, our data demonstrate that ARHGAP17 inhibits pathological cyclic strain-induced apoptosis in human PDL fibroblasts through inactivating Rac1/Cdc42. This study highlights the importance of Rho signalling in the response of human PDL fibroblasts to mechanical stress.

Tissue Engineering and Regenerative Medicine: Achievements, Future, and Sustainability in Asia

Exploring innovative solutions to improve the healthcare of the aging and diseased population continues to be a global challenge. Among a number of strategies toward this goal, tissue engineering and regenerative medicine (TERM) has gradually evolved into a promising approach to meet future needs of patients. TERM has recently received increasing attention in Asia, as evidenced by the markedly increased number of researchers, publications, clinical trials, and translational products. This review aims to give a brief overview of TERM development in Asia over the last decade by highlighting some of the important advances in this field and featuring major achievements of representative research groups. The development of novel biomaterials and enabling technologies, identification of new cell sources, and applications of TERM in various tissues are briefly introduced. Finally, the achievement of TERM in Asia, including important publications, representative discoveries, clinical trials, and examples of commercial products will be introduced. Discussion on current limitations and future directions in this hot topic will also be provided.

Inhibiting cancer metabolism by aromatic carbohydrate amphiphiles that act as antagonists of the glucose transporter GLUT1

We report on aromatic N-glucosides that inhibit selectively the cancer metabolism via two coexistent mechanisms: by initial deprivation of the glucose uptake through competitive binding in the glucose binding pocket of GLUT1 and by formation of a sequestering nanoscale supramolecular network at the cell surface through localized (biocatalytic) self-assembly. We demonstrate that the expression of the cancer associated GLUT1 and alkaline phosphatase are crucial for the effectiveness of this combined approach: cancer cells that overexpress both proteins are prompter to cell death when compared to GLUT1 overexpressing cells. Overall, we showcase that the synergism between physical and biochemical deprivation of cancer metabolism is a powerful approach for development of effective anticancer therapies.

Autophagy in periodontal ligament fibroblasts under biomechanical loading

Autophagy (cellular self-consumption) is an adaptive stress response and an important aspect of adaption to mechanical loading. If mechanical forces are associated with autophagy regulation in periodontal ligament (PDL) fibroblasts is still unknown. The aim of this study was to analyze the influence of force magnitude on autophagy regulation and subsequently on cell death in human PDL fibroblasts. Autophagy-associated genes were analyzed with a specific PrimePCR assay after 24 h of stimulation with high (STSH) and low magnitudes (STSL) of static tensile strain applied to PDL fibroblasts. Based on the results, targets were selected for further real-time PCR analysis. The autophagic flux was assessed by immunoblotting for autophagy marker microtubule-associated protein 1, light chain 3, and by autophagosome staining. Cell death was determined by TUNEL assay and Cell Death Detection ELISA^PLUS. Autophagy was induced pharmacologically by rapamycin and inhibited by chloroquine. For statistical analysis, the Kruskal Wallis test followed by the post-hoc Dunnett's test was used. Static tensile strain had regulatory effects on mRNA expression of multiple autophagy-associated targets. Stimulation with STSH induced mRNA expression changes in more autophagy-associated targets than STSL. The autophagic flux was induced by STSH while STSL had no significant effect on autophagosome formation. Furthermore, autophagy inhibition led to increased cell death. Low magnitudes of tensile strain seem to have cell-protective properties. Taken together, our findings provide novel insights about autophagy regulation by biomechanical loading in human PDL fibroblasts. Our results suggest a gradual response of autophagy to static tensile strain in human PDL fibroblasts.

Potential renoprotective effects of silymarin against vancomycin-induced nephrotoxicity in rats

Silymarin (SLY), a flavonoid complex isolated from the seeds of Silybum marianum (Asteraceae), has antioxidant, anti-apoptotic, anti-inflammatory, and anti-lipid peroxidative effects. Vancomycin (VA), used for treating serious infections, has been associated with nephrotoxicity, which limits its use. Therefore, this study aimed to investigate the potential renoprotective effects of SLY on VA-induced nephrotoxicity using renal, apoptotic (caspase-3, caspase-8, and caspase-9 enzyme activities), and oxidative stress [nitric oxide (NO) and malondialdehyde (MDA)] markers; serum blood urea nitrogen (BUN) and creatinine levels; and histopathological examination. A total of 49 male Wistar albino rats were used (n = 7): control [saline, intraperitoneally (i.p.)], dimethyl sulfoxide (i.p.), VA [400 mg/(kg-day), i.p.], SLY100 [100 mg/(kg-day), i.p.], VA + SLY50 [50 mg/(kg-day), i.p.], VA + SLY100 [100 mg/(kg-day), i.p.], and VA + SLY200 [200 mg/(kg-day), i.p.]. SLY was administered once daily for 8 days. One day after the first treatment of SLY, VA administration was started and continued for 7 days. The levels of serum creatinine and BUN were evaluated using ELISA, caspase enzyme activities and levels of MDA and NO in the kidney tissues were evaluated by the colorimetric methods. The serum BUN, creatinine, NO, MDA levels, and caspase activities were significantly higher in VA group than in control (p < 0.05). However, caspase activities were significantly lower in VA + SLY200 than in VA (p < 0.05). The MDA, serum BUN, and creatinine levels were significantly lower in VA + SLY (50, 100, and 200) groups than in VA group (p < 0.05). VA + SLY200 was found to be the most effective group based on the caspase activities; MDA, NO, serum BUN, creatinine levels; and histopathological findings.

Hesperidin structurally modified by gamma irradiation induces apoptosis in murine melanoma B16BL6 cells and inhibits both subcutaneous tumor growth and metastasis in C57BL/6 mice

Hesperidin is a flavonoid which occurs in citrus fruits. Hesperidin was gamma-irradiated at doses of 0, 30, 70, and 150 kGy. Gamma irradiation induced a decreased hesperidin peak, and a new radiolytic peak that gradually increased up to 150 kGy. The new radiolytic peak was fractionated, and the fractionated hesperidin derivative was used for subsequent experiments. Hesperidin gamma-irradiated at 150 kGy was toxic toward B16BL6 cells, but not toward bone marrow-derived macrophages. This cytotoxicity was exerted via induction of apoptosis, as reflected by the high population of double-positive cells, increased sub-G1 phase cells, depolarization of matrix metalloproteinase, production of reactive oxygen species, weakness of cell adhesion, changes in cell morphology, and inhibition of B16BL6 cell migration. Furthermore, 150 kGy gamma-irradiated hesperidin decreased the expression of Bcl-2 and pro-caspases-3 and -9, increased the expression of Bax and cytosolic cytochrome c, and increased the cleavage of poly ADP ribose polymerase. In vitro mechanistic study revealed that 150 kGy gamma-irradiated hesperidin achieved significantly greater inhibition of lung metastasis and growth of melanoma B16BL6 cells in C57BL/6 mice than non-irradiated intact hesperidin did. These results suggest that the structural modification of hesperidin induced by gamma irradiation could facilitate the development of anti-cancer drugs.

Interaction between caspase-3 and caspase-5 in the stretch-induced programmed cell death in the human periodontal ligament cells

In our previous studies, programmed cell death (PCD) was induced in human periodontal ligament (PDL) cells, through activation of caspase-3 and upregulation of CASP5 gene (encoding caspase-5 protein), in response to mechanical stretch loading. The aim of this study is to explore the relationship between the inflammatory caspase, caspase-5, and the apoptotic executioner protein, caspase-3, in human PDL cells. Here, we found that cyclic stretching upregulated the activity and the protein expression level of caspase-3 and -5 and the addition of the caspase-3 inhibitor or caspase-5 inhibitor significantly inhibited the stretch-induced PCD. Meanwhile, the inhibition of caspase-5 inhibited the activation of caspase-3 and vice versa. The result of coimmunoprecipitation also demonstrated that the expression of caspase-3 was immunoprecipitated with caspase-5. Thus, our study revealed that the in vitro application of cyclic stretching induced PCD by activation of caspase-3 and -5 in human PDL cells, and these two caspases could interact with each other after mechanical stretch loading. The study may facilitate further studies on the mechanism of stretch-induced PCD and help us understand the force-related periodontal homeostasis and remodeling better.

EGFR tyrosine kinase inhibitor HS-10182 increases radiation sensitivity in non-small cell lung cancers with EGFR T790M mutation

Objective:

To investigate the potential of HS-10182, a second-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), as a radiosensitizer in non-small cell lung cancer (NSCLC).

Methods:

Two cell lines of NSCLCs, A549 that possesses wild-type (WT) EGFRs and H1975 that possesses EGFR L858R/T790M double mutations, were treated with HS-10182 at various concentrations, and cell viabilities were determined using the MTS assay. The cells were tested by clonogenic survival assays to identify the radiosensitivity of both groups. Western blot was performed to analyze the expression of phosphorylated EGFR, AKT, DNA-dependent protein kinase, and catalytic subunit (DNA-PKcs) proteins. Immunofluorescence analyses were performed to examine the formation and changes in nuclear γ-H2AX foci. Cell apoptosis was examined by flow cytometry and Western blots for cleaved caspase-3, -8, -9, and cleaved poly ADP-ribose polymerase (PARP). Furthermore, we established xenograft models in mice and the effects of different treatments on tumor growth were then assessed.

Results:

Clonogenic survival assays revealed that HS-10182 significantly enhanced the radiosensitivity of H1975 cells but not A549 cells [dose enhancement ratios (DERs)=2.36 (P < 0.05) vs. 1.43 (P > 0.05)]. Western blot results showed that HS-10182 increased the levels of cleaved caspase-3, -8, -9, and cleaved PARP in H1975 cells but not in A549 cells. In addition, flow cytometry analysis showed that HS-10182 enhanced irradiation-induced apoptosis in H1975. Immunofluorescence results found that HS-10182 increased the average number of γ-H2AX foci after irradiation in H1975 cells, but not in A549 cells. Combined radiation and HS-10182 treatment increased the expression of DNA-PKcs but this increase was more significant in H1975 cells than in A549 cells. Moreover, HS-10182 suppressed the increased expression of Rad50 in H1975 cells in response to irradiation. In vivo experiments found that the combined therapy significantly inhibited tumor growth.

Conclusions:

HS-10182 enhances the radiosensitivity of H1975 cells which is possibly because that HS-10182 could enhance irradiation-induced apoptosis, increase irradiation-induced DNA damage, and cause a delay in DNA damage repair. Our findings suggest that radiotherapy combined HS-10182 is a novel treatment for lung cancer cells which have acquired the T790M mutation. HS-10182 could be brought to the clinic as a radiosensitizer in NSCLCs with the EGFR T790M mutation.

Cyclic stretch-induced the cytoskeleton rearrangement and gene expression of cytoskeletal regulators in human periodontal ligament cells

OBJECTIVE

This study aimed to explore the mechanism of the stretch-induced cell realignment and cytoskeletal rearrangement by identifying several mechanoresponsive genes related to cytoskeletal regulators in human PDL cells.

MATERIAL AND METHODS

After the cells were stretched by 1, 10 and 20% strains for 0.5, 1, 2, 4, 6, 12 or 24 h, the changes of the morphology and content of microfilaments were recorded and calculated. Meanwhile, the expression of 84 key genes encoding cytoskeletal regulators after 6 and 24 h stretches with 20% strain was detected by using real-time PCR array. Western blot was applied to identify the protein expression level of several cytoskeletal regulators encoded by these differentially expressed genes.

RESULTS

The confocal fluorescent staining results confirmed that stretch-induced realignment of cells and rearrangement of microfilaments. Among the 84 genes screened, one gene was up-regulated while two genes were down-regulated after 6 h stretch. Meanwhile, three genes were up-regulated while two genes were down-regulated after 24 h stretch. These genes displaying differential expression included genes regulating polymerization/depolymerization of microfilaments (CDC42EP2, FNBP1L, NCK2, PIKFYVE, WASL), polymerization/depolymerization of microtubules (STMN1), interacting between microfilaments and microtubules (MACF1), as well as a phosphatase (PPP1R12B). Among the proteins encoded by these genes, the protein expression level of Cdc42 effector protein-2 (encoded by CDC42EP2) and Stathmin-1 (encoded by STMN1) was down-regulated, while the protein expression level of N-WASP (encoded by WASL) was up-regulated.

CONCLUSION

The present study confirmed the cyclic stretch-induced cellular realignment and rearrangement of microfilaments in the human PDL cells and indicated several force-sensitive genes with regard to cytoskeletal regulators.