Arsenic Trioxide Decreases Lymphangiogenesis by Inducing Apoptotic Pathways and Inhibition of Important Endothelial Cell Receptors

Tumor-induced lymphangiogenesis is strongly associated with the formation of tumor metastasis. Therefore, the regulation of lymphangiogenesis offers a promising target in cancer therapy. Arsenic trioxide (ATO) is highly effective in the treatment of patients with acute promyelocytic leukemia (APL). As ATO mediates anti-angiogenic effects on endothelial and tumor cells, we aimed to explore the impact of ATO on lymphangiogenesis in human lymphatic endothelial cells (LEC). The BrdU assay and flow cytometry analysis were used to evaluate the influence of ATO on the proliferation and cell cycle distribution of LECs. The lymphatic suppression effects of ATO were investigated in vitro using the lymphatic tube formation assay. The effects of ATO on apoptosis, mitochondrial membrane potential and endothelial cell receptors were investigated by Western blotting, ELISA, flow cytometry and qRT-PCR. The treatment of LECs with ATO attenuated cell proliferation, blocked tube formation and induced subG0/G1 arrest in LECs, thus suggesting enhanced apoptosis. Although subG0/G1 arrest was accompanied by the upregulation of p21 and p53, ATO treatment did not lead to visible cell cycle arrest in LECs. In addition, ATO caused apoptosis via the release of cytochrome c from mitochondria, activating caspases 3, 8 and 9; downregulating the anti-apoptotic proteins survivin, XIAP and cIAP-2; and upregulating the pro-apoptotic protein Fas. Furthermore, we observed that ATO inhibited the VEGF-induced proliferation of LECs, indicating that pro-survival VEGF/VEGFR signaling was affected by ATO treatment. Finally, we found that ATO inhibited the expression of the important endothelial cell receptors VEGFR-2, VEGFR-3, Tie-2 and Lyve-1. In conclusion, we demonstrate that ATO inhibits lymphangiogenesis by activating apoptotic pathways and inhibiting important endothelial cell receptors, which suggests that this drug should be further evaluated in the treatment of tumor-associated lymphangiogenesis.

Caloric Restriction Mitigates Kidney Fibrosis in an Aged and Obese Rat Model

Caloric restriction is an effective intervention to protract healthspan and lifespan in several animal models from yeast to primates, including humans. Caloric restriction has been found to induce cardiometabolic adaptations associated with improved health and to delay the onset and progression of kidney disease in different species, particularly in rodent models. In both aging and obesity, fibrosis is a hallmark of kidney disease, and epithelial-mesenchymal transition is a key process that leads to fibrosis and renal dysfunction during aging. In this study, we used an aged and obese rat model to evaluate the effect of long-term (6 months) caloric restriction (-40%) on renal damage both from a structural and functional point of view. Renal interstitial fibrosis was analyzed by histological techniques, whereas effects on mesenchymal (N-cadherin, Vimentin, Desmin and α-SMA), antioxidant (SOD1, SOD2, Catalase and GSTP1) inflammatory (YM1 and iNOS) markers and apoptotic/cell cycle (BAX, BCL2, pJNK, Caspase 3 and p27) pathways were investigated using Western blot analysis. Our results clearly showed that caloric restriction promotes cell cycle division and reduces apoptotic injury and fibrosis phenotype through inflammation attenuation and leukocyte infiltration. In conclusion, we highlight the beneficial effects of caloric restriction to preserve elderly kidney function.

Interleukin-18 Inhibition Protects Against Intervertebral Disc Degeneration via the Inactivation of Caspase-3/9 Dependent Apoptotic Pathways

BACKGROUND

The present study was designed to identify and understand the potential effectiveness of therapeutic target in intervertebral disc degeneration (IVDD) and its regulation mechanism.

METHODS

The role and mechanism of interleukin-18 (IL-18) in the disease were investigated. The IVDD degenerative nucleus pulposus (NP) tissues from the human and mouse models were used.A total of three groups of Male BALB/c mice were randomly made i.e control, IVDD, and IVDD+Ad-shIL-18 groups. After Ad-shIL-18 transfection, the expression of ECM synthesis related protein Aggrecan (ACAN) and Collagen II, apoptotic effector Caspases (Caspase-3, 8, 9, 12 and Cleaved-Caspase 3, 8, 9, 12), pro-apoptotic gene Bax and anti-apoptotic factors Bcl-2 in NP cells of the human were evaluated.

RESULTS

The results of our study revealed that the mRNA and protein expression levels of IL-18 were notably increased in the NP tissues of IVDD patients and mice models. In the IVDD mice model, Ad-sh-IL-18 treatment reversed the IVDD progression. The levels of Aggrecan and Collagen II, contributing to ECM degradation in NP cells, were also significantly increased. Additionally, Ad-sh-IL-18 could inhibit the NP cell's apoptosis via regulating the caspase-3/9 pathway.

CONCLUSION

The IL-18 knockdown via the caspase-3/9 pathway, might reduce the NP cell's death as well as the imbalance between catabolism and anabolism of ECM in IVDD.

Vitexin isolated from Prosopis cineraria leaves induce apoptosis in K-562 leukemia cells via inhibition of the BCR-ABL-Ras-Raf pathway

OBJECTIVES

Leukemia is one of the severe cancer types all around the globe. Even though some chemotherapeutic drugs are available for treating leukemia, they have various side effects. As an alternative approach, herbal drugs are focused on current research to overcome leukemia. The present work was conducted to investigate the antileukemic mechanism of active phytochemical vitexin, which was isolated from ethno-medicine (Prosopis cineraria leaf) used by traditional healers of West Bengal, India.

METHODS

Antiproliferative mechanisms of selected phyto-compound against K-562 cells were evaluated using cellular uptake, morphological changes, DNA fragmentation, mitochondrial membrane potential and signaling pathways analysis.

KEY FINDINGS

Vitexin exhibited cytotoxicity by reducing mitochondrial membrane potential (32.40%) and causing DNA fragmentation (84.15%). The western blotting study indicated inhibition of cell survival proteins (BCR, ABL, H-RAS, N-RAS, K-RAS and RAF) and expression of apoptotic proteins (p38, BAX and caspase-9) in leukemia cells upon treatment with vitexin.

CONCLUSIONS

Based on the results, presently investigated phyto-compound vitexin could be considered for developing safe and natural drugs to treat leukemia after conducting suitable preclinical and clinical trials.

Animal Coronaviruses Induced Apoptosis

Apoptosis is a form of programmed death that has also been observed in cells infected by several viruses. It is considered one of the most critical innate immune mechanisms that limits pathogen proliferation and propagation before the initiation of the adaptive immune response. Recent studies investigating the cellular responses to SARS-CoV and SARS-CoV-2 infection have revealed that coronaviruses can alter cellular homeostasis and promote cell death, providing evidence that the modulation of apoptotic pathways is important for viral replication and propagation. Despite the genetic diversity among different coronavirus clades and the infection of different cell types and several hosts, research studies in animal coronaviruses indicate that apoptosis in host cells is induced by common molecular mechanisms and apoptotic pathways. We summarize and critically review current knowledge on the molecular aspects of cell-death regulation during animal coronaviruses infection and the viral–host interactions to this process. Future research is expected to lead to a better understanding of the regulation of cell death during coronavirus infection. Moreover, investigating the role of viral proteins in this process will help us to identify novel antiviral targets related to apoptotic signaling pathways.

Endoribonuclease ENDU-2 regulates multiple traits including cold tolerance via cell autonomous and nonautonomous controls in Caenorhabditis elegans

Environmental temperature acclimation is essential to animal survival, yet thermoregulation mechanisms remain poorly understood. We demonstrate cold tolerance in Caenorhabditis elegans as regulated by paired ADL chemosensory neurons via Ca²⁺-dependent endoribonuclease (EndoU) ENDU-2. Loss of ENDU-2 function results in life span, brood size, and synaptic remodeling abnormalities in addition to enhanced cold tolerance. Enzymatic ENDU-2 defects localized in the ADL and certain muscle cells led to increased cold tolerance in endu-2 mutants. Ca²⁺ imaging revealed ADL neurons were responsive to temperature stimuli through transient receptor potential (TRP) channels, concluding that ADL function requires ENDU-2 action in both cell-autonomous and cell-nonautonomous mechanisms. ENDU-2 is involved in caspase expression, which is central to cold tolerance and synaptic remodeling in dorsal nerve cord. We therefore conclude that ENDU-2 regulates cell type-dependent, cell-autonomous, and cell-nonautonomous cold tolerance.

Imbalance between pro-apoptotic and pro-survival factors in human retinal pericytes in diabetic-like conditions

PURPOSE

Loss of pericytes is one the key events in the pathogenesis of diabetic retinopathy. We have previously demonstrated that human retinal pericytes (HRP) are more vulnerable to intermittent than stable high glucose concentrations, with an increase in apoptosis. Our aim was to explore the expression of molecules involved in pro-apoptotic and survival pathways in pericytes cultured in stable/intermittent high glucose and/or hypoxia, to clarify the mechanisms of action of these diabetic-like stressing stimuli.

METHODS

Human retinal pericytes (HRP) were exposed intermittently at 48-hr intervals to high/physiological glucose for 8 days (intHG) and/or hypoxia over the last 48 hr. Control cells were kept in stable physiological and high glucose. Cell proliferation and apoptosis were assessed. The expression of pro-apoptotic and pro-survival molecules was evaluated by Western blotting. Caspase-8 translocation from the cytoplasm into the nucleus was checked by Western blotting of nuclear versus cytoplasmic fractions and immunofluorescence.

RESULTS

Hypoxia, alone and combined with intHG, increased HRP apoptosis and decreased proliferation. Pro-apoptotic molecules increased in HRP cultured in these conditions, while some survival markers decreased. Conversely, in stable HG, pro-apoptotic molecules were stable or even decreased, and survival factors increased. Translocation of caspase-8 from cytoplasm into nucleus indicates a primary role for this molecule in inducing apoptosis.

CONCLUSION

Diabetic-like conditions are able to stimulate pericyte apoptosis through activation of pro-apoptotic molecules, leading to an imbalance between pro-apoptotic and survival signalling pathways, with caspase-8 playing a pivotal role. Our identification of such intermediates could help finding new therapeutic approaches for the prevention of diabetic retinopathy.

Evaluation of in vitro cytotoxicity, biocompatibility, and changes in the expression of apoptosis regulatory proteins induced by cerium oxide nanocrystals

Cerium oxide nanocrystals (CeO₂-NCs) exhibit superoxide dismutase and catalase mimetic activities. Based on these catalytic activities, CeO₂-NCs have been suggested to have the potential to treat various diseases. The crystalline size of these materials is an important factor that influences the performance of CeO₂-NCs. Previous reports have shown that several metal-based nanocrystals, including CeO₂-NCs, can induce cytotoxicity in cancer cells. However, the underlying mechanisms have remained unclear. To characterize the anticancer activities of CeO₂-NCs, several assays related to the mechanism of cytotoxicity and induction of apoptosis has been performed. Here, we have carried out a systematic study to characterize CeO₂-NCs phase purity (X-ray diffraction), morphology (electron microscopy), and optical features (optical absorption, Raman scattering, and photoluminescence) to better establish their potential as anticancer drugs. Our study revealed anticancer effects of CeO₂-NCs in HT29 and SW620 colorectal cancer cell lines with half-maximal inhibitory concentration (IC₅₀) values of 2.26 and 121.18 μg ml^-1, respectively. Reductions in cell viability indicated the cytotoxic potential of CeO₂-NCs in HT29 cells based on inverted and florescence microscopy assessments. The mechanism of cytotoxicity confirmed by estimating possible changes in the expression levels of Bcl2, BclxL, Bax, PARP, cytochrome c, and β-actin (control) proteins in HT29 cells. Down-regulation of Bcl2 and BclxL and up-regulation of Bax, PARP, and cytochrome c proteins suggested the significant involvement of CeO₂-NCs exposure in the induction of apoptosis. Furthermore, biocompatibility assay showed minimum effect of CeO₂-NCs on human red blood cells.

Amide-linked local anesthetics induce apoptosis in human non-small cell lung cancer

BACKGROUND

A retrospective analysis of patients undergoing cancer surgery suggested that using local anesthetics could reduce cancer recurrence and improve survival rate. Previous studies have indicated that local anesthetics may induce apoptosis in several kinds of cells in vitro, but the mechanism is unclear.

METHODS

Cell viability was analyzed by MTS; reactive oxygen species (ROS), mitochondrial membrane potential (MMP, ∆Ψm), cell cycle distribution, and cell apoptosis assay were detected by flow cytometry; DNA damage was measured by comet assay; cell invasion and migration were observed by microscopy; The expression level of related proteins was detected by western blot assay.

RESULTS

The results indicated that lidocaine and ropivacaine could decrease viability, induce G0/G1 phase arrest and apoptosis in human non-small cell lung cancer (NSCLC) cells A549 and H520. Invasion and migration were suppressed. Western blot indicated the related apoptotic pathways proteins changed accordingly. Additionally, lidocaine and ropivacaine downregulated ∆Ψm, provoked DNA damage, upregulated ROS production and activated mitogen-activated protein kinase (MAPK) pathways in A549 and H520 cells.

CONCLUSIONS

The cytotoxic effect of amide-linked local anesthetics on NSCLC cells were mainly due to apoptosis. The antitumor mechanism of lidocaine and ropivacaine may involve apoptotic pathways and MAPK pathways.

Comparative Proteomic Analysis of Advanced Ovarian Cancer Tissue to Identify Potential Biomarkers of Responders and Nonresponders to First-Line Chemotherapy of Carboplatin and Paclitaxel

Conventional treatment for advanced ovarian cancer is an initial debulking surgery followed by chemotherapy combination of carboplatin and paclitaxel. Despite initial high response, three-fourths of these women experience disease recurrence with a dismal prognosis. Patients with advanced-stage ovarian cancer who underwent cytoreductive surgery were enrolled and tissue samples were collected. Post surgery, these patients were started on chemotherapy and followed up till the end of the cycle. Fluorescence-based differential in-gel expression coupled with mass spectrometric analysis was used for discovery phase of experiments, and real-time polymerase chain reaction, Western blotting, and pathway analysis were performed for expression and functional validation of differentially expressed proteins. While aldehyde reductase, hnRNP, cyclophilin A, heat shock protein-27, and actin are upregulated in responders, prohibitin, enoyl-coA hydratase, peroxiredoxin, and fibrin-β are upregulated in the nonresponders. The expressions of some of these proteins correlated with increased apoptotic activity in responders and decreased apoptotic activity in nonresponders. Therefore, the proteins qualify as potential biomarkers to predict chemotherapy response.

Cancer stem cells: are they responsible for treatment failure?

Overcoming resistance to standard anticancer treatments represents a significant challenge. The interest regarding cancer stem cells, a cellular population that has the ability to self-renew and to propagate the tumor, was prompted by experimental evidence delineating the molecular mechanisms that are selectively activated in this cellular subset in order to survive chemotherapy. This has also stimulated combination strategies aimed at rendering cancer stem cells vulnerable to anticancer agents. Moreover, cancer stem cells offer a unique opportunity for modeling human cancers in mice, thus emerging as a powerful tool for testing novel drugs and combinations in a simulation of human disease. These novel animal models may lay the foundation for a new generation of clinical trials aimed at anticipating the benefit to patients of anticancer therapies.

Curcumin-Protected PC12 Cells Against Glutamate-Induced Oxidative Toxicity

Glutamate is a major excitatory neurotransmitter present in the central nervous system. The glutamate/cystine antiporter system x ^_c- connects the antioxidant defense with neurotransmission and behaviour. Overactivation of ionotropic glutamate receptors induces neuronal death, a pathway called excitotoxicity. Glutamate-induced oxidative stress is a major contributor to neurodegenerative diseases including cerebral ischemia, Alzheimer's and Huntington's disease. Curcuma has a wide spectrum of biological activities regarding neuroprotection and neurocognition. By reducing the oxidative damage, curcumin attenuates a spinal cord ischemia-reperfusion injury, seizures and hippocampal neuronal loss. The rat pheochromocytoma (PC12) cell line exhibits many characteristics useful for the study of the neuroprotection and neurocognition. This investigation was carried out to determine whether the neuroprotective effects of curcumin can be observed via the glutamate-PC12 cell model. Results indicate that glutamate (20 mM) upregulated glutathione peroxidase 1, glutathione disulphide, Ca²⁺ influx, nitric oxide production, cytochrome c release, Bax/Bcl-2 ratio, caspase-3 activity, lactate dehydrogenase release, reactive oxygen species, H _² O _² , and malondialdehyde; and downregulated glutathione, glutathione reductase, superoxide dismutase and catalase, resulting in enhanced cell apoptosis. Curcumin alleviates all these adverse effects. Conclusively, curcumin can effectively protect PC12 cells against the glutamate-induced oxidative toxicity. Its mode of action involves two pathways: the glutathione-dependent nitric oxide-reactive oxygen species pathway and the mitochondria-dependent nitric oxide-reactive oxygen species pathway.

Ribonuclease binase inhibits primary tumor growth and metastases via apoptosis induction in tumor cells

Exogenous ribonucleases are known to inhibit tumor growth via apoptosis induction in tumor cells, allowing to consider them as promising anticancer drugs for clinical application. In this work the antitumor potential of binase was evaluated in vivo and the mechanism of cytotoxic effect of binase on tumor cells was comprehensively studied in vitro. We investigated tumoricidal activity of binase using three murine tumor models of Lewis lung carcinoma (LLC), lymphosarcoma RLS 40 and melanoma B-16. We show for the first time that intraperitoneal injection of binase at a dose range 0.1-5 mg/kg results in retardation of primary tumor growth up to 45% in LLC and RLS 40 and inhibits metastasis up to 50% in LLC and RLS 40 and up to 70% in B-16 melanoma. Binase does not exhibit overall toxic effect and displays a general systemic and immunomodulatory effects. Treatment of RLS 40-bearing animals with binase together with polychemotherapy revealed that binase decreases the hepatotoxicity of polychemotherapy while maintaining its antitumor effect. It was demonstrated that the cytotoxic effect of binase is realized via the induction of the intrinsic and extrinsic apoptotic pathways. Activation of intrinsic apoptotic pathway is manifested by a drop of mitochondrial potential, increase in calcium concentration and inhibition of respiratory activity. Subsequent synthesis of TNF-α in the cells under the action of binase triggers extrinsic apoptotic pathway through the binding of TNF with cell-death receptors and activation of caspase 8. Thus binase is a potential anticancer therapeutics inducing apoptosis in cancer cells.