Nitric oxide induces apoptosis in cutaneous T cell lymphoma (HuT-78) by downregulating constitutive NF-κB

Enhanced anti-cancer potency of sustainably synthesized anisotropic silver nanoparticles as compared with L-asparaginase

Acute lymphoblastic leukemia (ALL), a hematologic cancer that involves the production of abnormal lymphoid precursor cells, primarily affects children aged 2 to 10 years. The bacterial enzyme L-asparaginase produced from Escherichia coli is utilised as first-line therapy, despite the fact that 30 % of patients have a treatment-limiting hypersensitivity reaction. The current study elucidates the biosynthesis of extremely stable, water-dispersible, anisotropic silver nanoparticles (ANI Ag NPs) at room temperature and investigation of its anti-tumor potency in comparison to L-asparaginase. The optical, morphological, compositional, and structural properties of synthesized nanoparticles were evaluated using UV-Vis-NIR spectroscopy, Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy, and X-ray Diffractometer. The UV-Vis-NIR spectra revealed the typical Surface Plasmon Resonance (SPR) at 423 nm along with additional NIR absorption at 962 nm and 1153 nm, while TEM images show different shapes and sizes of Ag nanoparticles ranging from 6.81 nm to 46 nm, together confirming their anisotropic nature. Further, the MTT assay demonstrated promising anticancer effects of ANI Ag NPs with an IC50 value of ∼7 μg/mL against HuT-78 cells. These sustainable anisotropic silver nanoparticles exhibited approximately four times better cytotoxic ability (at and above 10 μg/mL concentrations) than L-asparaginase against HuT-78 cells (a human T lymphoma cell line). Apoptosis analysis by Wright-Geimsa, Annexin-V, and DAPI staining indicated the role of apoptosis in ANI Ag NPs-mediated cell death. The measurement of NO, and Bcl2 and cleaved caspase-3 levels by colorimetric method and immunoblotting, respectively suggested their involvement in ANI Ag NPs-elicited apoptosis. The findings indicate that the biogenic approach proposed herein holds tremendous promise for the rapid and straightforward design of novel multifunctional nanoparticles for the treatment of T cell malignancies.

Excess iron aggravates the severity of COVID-19 infection

Coronavirus disease-19 (COVID-19) can induce severe inflammation of the lungs and respiratory system. Severe COVID-19 is frequently associated with hyper inflammation and hyper-ferritinemia. High iron levels are known to trigger pro-inflammatory effects. Cumulative iron loading negatively impacts on a patients innate immune effector functions and increases the risk for infection related complications. Prognosis of severe acute respiratory SARS-CoV-2 patients may be impacted by iron excess. Iron is an essential co-factor for numerous essential cellular enzymes and vital cellular operations. Viruses hijack cells in order to replicate, and efficient replication requires an iron-replete host. Utilizing iron loaded cells in culture we evaluated their susceptibility to infection by pseudovirus expressing the SARS-CoV-2 spike protein and resultant cellular inflammatory response. We observed that, high levels of iron enhanced host cell ACE2 receptor expression contributing to higher infectivity of pseudovirus. In vitro Cellular iron overload also synergistically enhanced the levels of; reactive oxygen species, reactive nitrogen species, pro-inflammatory cytokines (IL-1β, IL-6, IL-8 & TNF-α) and chemokine (CXCL-1&CCL-4) production in response to inflammatory stimulation of cells with spike protein. These results were confirmed using an in vivo mouse model. In future, limiting iron levels may be a promising adjuvant strategy in treating viral infection.

Nitrate increases cisplatin chemosensitivity of oral squamous cell carcinoma via REDD1/AKT signaling pathway

Although cisplatin is one of the chemotherapeutics most frequently used in oral squamous cell carcinoma (OSCC) treatment, it exerts multiple side effects and poor chemosensitivity. Nitrate reportedly demonstrates several beneficial biological functions, and synthesized nitrates enhance the therapeutic efficacy of chemotherapy. However, the role of inorganic nitrate in cisplatin chemotherapy remains unclear. We therefore investigated the effect of inorganic nitrate exerted on cisplatin sensitivity in OSCC. We found that nitrate did not affect OSCC cell growth and apoptosis in OSCC cells and OSCC xenograft tumor animal studies. Cisplatin induced REDD1 expression and AKT activation in OSCC. However, nitrate could increase cisplatin chemosensitivity, reduce its REDD1 expression, and attenuate AKT signaling activation in OSCC cells. Dysregulation of high levels of REDD1, which could enhance AKT activation, was positively associated with poor prognosis in OSCC patients. Thus, reduced REDD1 expression and retarded AKT activation induced by inorganic nitrate might be a new potential approach to the sensitization of oral cancer to cisplatin treatment in the future.

Prokaryotic Expression, In Vitro Biological Analysis, and In Silico Structural Evaluation of Guinea Pig IL-4

Interleukin-4 is a signature cytokine of T-helper type 2 (Th2) cells that play a major role in shaping immune responses. Its role in highly relevant animal model of tuberculosis (TB) like guinea pig has not been studied till date. In the current study, the guinea pig IL-4 gene was cloned and expressed using a prokaryotic expression vector (pET30 a(+)). This approach yielded a recombinant protein of 19 kDa as confirmed by mass spectrometry analysis and named as recombinant guinea pig (rgp)IL-4 protein. The authenticity of the expression of rgpIL-4 protein was further verified through polyclonal anti-IL4 antiserum raised in rabbits that showed specific and strong binding with the recombinant protein. The biological activity of the rgpIL-4 was ascertained in RAW264.7 cells where LPS-treated nitric oxide (NO) production was found to be suppressed in the presence of this protein. The three-dimensional structure of guinea pig IL-4 was predicted by utilizing the template structure of human interleukin-4, which shared a sequence homology of 58%. The homology modeling result showed clear resemblance of guinea pig IL-4 structure with the human IL-4. Taken together, our study indicates that the newly expressed, biologically active rgpIL-4 protein could provide deeper understanding of the immune responses in guinea pig to different infectious diseases like TB and non-infectious ones.

Nitric oxide, a communicator between tumor cells and endothelial cells, mediates the anti-tumor effects of Marsdenia Tenacissima Extract (MTE)

ETHNOPHARMACOLOGICAL RELEVANCE

Marsdenia tenacissima (Roxb.) Wight & Arn is a well-known traditional Chinese medicine for treating cancer. The anti-tumor effects of the water soluble component of M. tenacissima (MTE, M. Tenacissima Extract) have been intensely studied. However, the roles of microenvironmental cells in mediating the anti-tumor actions of MTE remain to be defined.

AIM OF THE STUDY

To determine the roles of nitric oxide (NO) released by endothelial cells (ECs), an important component of tumor microenvironment, in regulating the anti-cancer effects of MTE, and to explore the underlying mechanisms.

MATERIALS AND METHODS

Co-culture system of ECs and A549 non-small cell lung cancer (NSCLC) cells was established for determining the interactions of ECs and lung cancer cells. Nitro-L-arginine methyl ester hydrochloride (L-NAME) was used to inhibit the production of NO. Cell viability was examined using cell counting kit 8 and 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. NO assay and Western blot were used to determine the involved signaling pathway. Primary lung microenvironmental cells (PLMCs) were cultured to examine the roles of NO released from the lung microenvironment in regulating the anti-cancer effects of MTE. A subcutaneous xenograft model was established to determine the involvement of NO in effects of MTE against NSCLCs in vivo.

RESULTS

In the co-culture system of ECs and A549 NSCLC cells, MTE (30 mg/mL) treatment reduced viability of lung cancer cells. However, when L-NAME (a nitric oxide synthase (NOS) inhibitor, 300 μM) was introduced into the co-culture system, the NSCLC-inhibiting effects of MTE were significantly suppressed. By contrast, addition of L-NAME (300 μM) did not affect the anti-cancer efficiency of MTE when ECs were not present. Mechanistically, MTE enhanced endothelial production of NO via stimulating PKA-endothelial nitric oxide synthase (eNOS) signaling. Elevated levels of NO inhibited proliferation and promoted apoptosis of the A549 NSCLC cells. Importantly, PKA-eNOS-NO signaling was effective in mediating the anti-cancer effects of MTE, when lung cancer cells were co-cultured with PLMCs. Finally, oral administration of MTE to the subcutaneous xenograft mice significantly suppressed tumor growth, while elevated NO productions. Plasma NO was also revealed to be negatively correlated with the tumor weight.

CONCLUSIONS

ECs significantly contributed to anti-cancer effects of MTE by elevating production of NO, in a PKA-dependent manner. The present study revealed a novel anti-cancer mechanism of MTE through regulating the function of ECs, an important component of tumor microenvironment.

Inhibition of Dimethylarginine Dimethylaminohydrolase (DDAH) Enzymes as an Emerging Therapeutic Strategy to Target Angiogenesis and Vasculogenic Mimicry in Cancer

The small free radical gas nitric oxide (NO) plays a key role in various physiological and pathological processes through enhancement of endothelial cell survival and proliferation. In particular, NO has emerged as a molecule of interest in carcinogenesis and tumor progression due to its crucial role in various cancer-related events including cell invasion, metastasis, and angiogenesis. The dimethylarginine dimethylaminohydrolase (DDAH) family of enzymes metabolize the endogenous nitric oxide synthase (NOS) inhibitors, asymmetric dimethylarginine (ADMA) and monomethyl arginine (L-NMMA), and are thus key for maintaining homeostatic control of NO. Dysregulation of the DDAH/ADMA/NO pathway resulting in increased local NO availability often promotes tumor growth, angiogenesis, and vasculogenic mimicry. Recent literature has demonstrated increased DDAH expression in tumors of different origins and has also suggested a potential ADMA-independent role for DDAH enzymes in addition to their well-studied ADMA-mediated influence on NO. Inhibition of DDAH expression and/or activity in cell culture models and in vivo studies has indicated the potential therapeutic benefit of this pathway through inhibition of both angiogenesis and vasculogenic mimicry, and strategies for manipulating DDAH function in cancer are currently being actively pursued by several research groups. This review will thus provide a timely discussion on the expression, regulation, and function of DDAH enzymes in regard to angiogenesis and vasculogenic mimicry, and will offer insight into the therapeutic potential of DDAH inhibition in cancer based on preclinical studies.

NO-Donor Nitrosyl Iron Complex with 2-Aminophenolyl Ligand Induces Apoptosis and Inhibits NF-κB Function in HeLa Cells

NO donating iron nitrosyl complex with 2-aminothiophenyl ligand (2-AmPh complex) was studied for its ability to cause cell death and affect nuclear factor kappa B (NF-κB) signaling. The complex inhibited viability of HeLa cells and induced cell death that was accompanied by loss of mitochondrial membrane potential and characteristic for apoptosis phosphatidylserine externalization. At IC50, 2-AmPh caused decrease in nuclear content of NF-κB p65 polypeptide and mRNA expression of NF-κB target genes encoding interleukin-8 and anti-apoptotic protein BIRC3. mRNA levels of interleukin-6 and anti-apoptotic protein BIRC2 encoding genes were not affected. Our data demonstrate that NO donating iron nitrosyl complex 2-AmPh can inhibit tumor cell viability and induce apoptosis that is preceded by impairment of NF-κB function and suppression of a subset of NF-κB target genes.

Effects of nitric oxide on the biological behavior of HepG2 human hepatocellular carcinoma cells

Many studies have found the function of nitric oxide (NO) in cancer as a pro-neoplastic vs. an anti-neoplastic effector, but the role of NO in hepatocellular carcinoma (HCC) remains unclear. The present study aimed to investigate the effects of nitric oxide (NO) on the biological behavior of the human hepatocellular carcinoma cell line HepG2. HepG2 cell was cultured in vitro and treated with or without sodium nitroprusside (SNP), a NO donor. Subsequently, we evaluated the effects of NO in cell proliferation, cell cycle, apoptosis, migration and invasion by MTT assay, flow cytometry, wound healing assay and Matrigel invasion assay. We demonstrate that NO significantly inhibited HepG2 cell proliferation by inducing G0/G1 phase arrest in a dose-dependent manner. In addition, compared to the control group, cells treated with SNP showed obviously higher apoptosis ratios in a dose-dependent manner. Furthermore, we revealed that NO effectively inhibited the ability of migration and invasion of HepG2 cells. Taken together, our results suggested that NO has an important role in the regulation of biological behavior in HepG2 cells and the potential for use in the prevention and treatment of HCC.

Alkylphosphocholines and curcumin induce programmed cell death in cutaneous T-cell lymphoma cell lines

While most patients with early-stage cutaneous T-cell lymphomas (CTCL) have a very good prognosis, the survival of patients with extensive tumour stage and visceral involvement remains extremely poor and necessitates the development of more effective treatment modalities. In this study, we evaluated the in vitro effects of two alkylphosphocholines (APCs, miltefosine and erufosine) and the polyphenolic compound curcumin on 5 human CTCL cell lines (Hut-78, HH, MJ, My-La CD4+ and My-La CD8+). All tested drugs showed considerable cytotoxic activity, as determined by the MTT dye reduction assay. The IC50 values of both APCs ranged from the low micromolar level (Hut-78 cells) to 60-80μM (HH cells). The IC50 values of curcumin ranged from 12 to 24μM. All tested drugs induced apoptosis, as ascertained by morphological changes, DNA fragmentation and activation of caspase cascades. Miltefosine and erufosine induced dephosphorylation of Akt in My-La CD8+ cells and phosphorylation of JNK in Hut-78 and My-La CD8+ cells. APCs increased the level of the autophagic marker LC3B in Hut-78 and MJ cells. Results from co-treatment with autophagy modulators suggested that the cytotoxicity of APCs in CTCL cells is mediated, at least in part, by induction of autophagy.

Pentoxifylline augments TRAIL/Apo2L mediated apoptosis in cutaneous T cell lymphoma (HuT-78 and MyLa) by modulating the expression of antiapoptotic proteins and death receptors

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising anticancer agent but cutaneous T lymphoma cells (CTCL) are less sensitive to TRAIL-induced apoptosis. Here, we report that pentoxifylline (PTX), a phosphodiesterase inhibitor, augments TRAIL-mediated apoptosis in HuT-78 and MyLa cells through modulating extrinsic death receptors and intrinsic mitochondria dependent pathways. Our results clearly show that PTX augments TRAIL-mediated activation of caspase-8 and induces cleavage of Bid, although PTX alone cannot activate caspase-8. This is followed by cytochrome c release and subsequent, activation of caspase-9 and caspase-3 and cleavage of poly (ADP ribose) polymerase (PARP). Combined treatment downregulates the expression of various antiapoptotic proteins including c-FLIP, Bcl-xl, cIAP-1, cIAP-2 and XIAP. PTX induces the expression of death receptors DR4 and DR5 on cell surface of both the cell types where c-Jun NH2-terminal kinase (JNK) pathway plays an important role. Moreover, combined silencing of DR4 and DR5 by small interfering RNA abrogates the ability of PTX to induce TRAIL-mediated apoptosis. Thus, this is the first demonstration that PTX can potentiate TRAIL-mediated apoptosis through downregulation of cell survival gene products and upregulation of death receptors.

Antifibrotic effects of ZK14, a novel nitric oxide-donating biphenyldicarboxylate derivative, on rat HSC-T6 cells and CCl4-induced hepatic fibrosis

AIM

To study the pharmacologic effect of ZK(14), a novel nitric oxide-donating biphenyldicarboxylate (DDB) derivative, on HSC-T6 cells and on CCl(4)-induced hepatic fibrosis.

METHODS

Inhibition of HSC-T6 cell growth by ZK(14) was evaluated by MTT assay. The effect of ZK(14) on the percentage of HSC-T6 cells undergoing apoptosis was measured using Annexin-V/PI double-staining and TUNEL assay. Mitochondrial membrane potential (MMP) and caspase activities were tested. Hepatic fibrosis was induced in Sprague-Dawley rats by intraperitoneal injection with 14% CCl(4). Rats with hepatic fibrosis were randomly divided into four groups: model control, ZK(14) (20 mg/kg), ZK(14) (10 mg/kg) and DDB (5 mg/kg). Levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), hyaluronic acid (HA), type III collagen (PCIII), and nitric oxide (NO) were assessed, and liver samples were stained with hematoxylin-eosin. The NO level in cells treated with ZK(14) in vitro was also measured.

RESULTS

The effect of ZK(14) on HSC-T6 cell apoptosis was concentration- and time-dependent, with up to 50% of cells becoming apoptotic when exposed to 100 mumol/L ZK(14) for 18 h. ZK(14) treatment resulted in mitochondrial membrane depolarization and activation of caspases 3 and 9. At a dose of 20 mg/kg, ZK(14) significantly decreased serum transaminase (AST, ALT) activities and fibrotic index (HA, PCIII) levels and significantly inhibited fibrogenesis.

CONCLUSION

These data indicate that ZK(14), a novel NO-donating DDB derivative, promotes HSC-T6 apoptosis in vitro through a signaling mechanism involving mitochondria and caspase activation and it inhibits CCl(4)-induced hepatic fibrosis in vivo. The results suggest that ZK(14) has potential therapeutic value in the treatment of hepatic fibrosis.

High-throughput assay of nitric oxide metabolites in human plasma without deproteinization by lab-on-a-chip electrophoresis using a zwitterionic additive

In order to develop a high-throughput assay for nitric oxide metabolites, nitrite (NO2-) and nitrate (NO3-), in biological fluids, we have investigated the simultaneous determination of them using an electrophoretic lab-on-a-chip (microchip capillary electrophoresis, MCE) technique. In this study, in order to establish an MCE assay process without deproteinization, the addition of a zwitterionic additive into the running buffer to reduce the adsorption of protein onto the surface of channel was investigated. Initially, some zwitterionic additives were investigated by making a comparison of relative standard deviations (RSDs) of the migration times for NO2(-) and NO3(-) on capillary electrophoresis. From the results of our comparison of the RSD values, 2% (w/w) N-cyclohexyl-2-aminoethanesulfonic acid (CHES) was selected. As a result of the application of the running buffer with CHES to the MCE process, the complete separation of NO2(-) and NO3(-) in human plasma without deproteinization was achieved within 1 min. Since the RSD values of the positions of the peaks were less than 2.3%, beneficial reduction effects on MCE were suggested. When we used an internal standard method in order to correct the injection volume, the RSDs of the peak heights and areas were less than 10%, and the correlation coefficients of spiked calibration curves ranging from 0 to 350 microM were 0.999 and 0.997 for NO2(-) and NO3(-), respectively. The limits of detection (S/N=3) were 53 microM for NO2(-) and 41 microM for NO3(-). Moreover, the correlation coefficients in excess of 0.99 between the MCE method and a conventional Griess method were achieved for both NO2(-) and NO3(-). Consequently, the possibility of establishing a high-throughput assay process was obtained by utilizing 2% (w/w) CHES to reduce protein adsorption.

Post-translational modifications induced by nitric oxide (NO): implication in cancer cells apoptosis

Post-translational modifications of proteins can regulate the balance between survival and cell death signals. It is increasingly recognized that nitric oxide (NO) and reactive oxygen species (ROS)-induced post-translational modifications could play a role in cell death. This review provides an introduction of current knowledge of NO proteins modifications promoting or inhibiting cell death with special attention in cancer cells.

NO-donating aspirin inhibits the activation of NF-kappaB in human cancer cell lines and Min mice

Nitric oxide-donating aspirin (NO-ASA) is a promising agent for the control of cancer, whose mechanism of action remains unclear. NF-kappaB is an important signaling molecule in the pathogenesis of cancer. We studied in several human colon (HT-29, HCT-15, LoVo, HCT116 and SW-480), pancreatic (BxPC-3, MIA PaCa-2) and breast (MDA-MB-231 and MCF-7) cancer cell lines, the effect of NO-ASA on NF-kappaB activation, determined by electrophoretic mobility shift assays, immunofluorescence and western blot analyses of nuclear proteins. NO-ASA inhibited NF-kappaB activation, as early as 30 min and with IC(50)s ranging between 0.83 and 64 microM. Such inhibition was also observed at NO-ASA concentrations that had an insignificant or marginal effect on cell growth. The effect of NO-ASA on NF-kappaB binding to DNA was significantly correlated with its effect on cell growth (P < 0.05) indicating that the growth inhibitory effect of NO-ASA may be mediated by its effect on NF-kappaB. Compared with control, NO-ASA decreased NF-kappaB activation in intestinal epithelial cells of APC(min+/-) mice by 38.4% (P < 0.01). Western blot and immunofluorescence analyses revealed that the nuclear levels of the p50 and p65 NF-kappaB subunits were virtually unaffected, suggesting an inhibitory mechanism different from suppressed subunit translocation into the nucleus. Inhibition of NF-kappaB activation by NO-ASA may account, at least in part, for its chemopreventive efficacy.

Neural stem cells, inflammation and NF-kappaB: basic principle of maintenance and repair or origin of brain tumours?

Several recent reports suggest that inflammatory signals play a decisive role in the self-renewal, migration and differentiation of multipotent neural stem cells (NSCs). NSCs are believed to be able to ameliorate the symptoms of several brain pathologies through proliferation, migration into the area of the lesion and either differentiation into the appropriate cell type or secretion of anti-inflammatory cytokines. Although NSCs have beneficial roles, current evidence indicates that brain tumours, such as astrogliomas or ependymomas are also caused by tumour-initiating cells with stem-like properties. However, little is known about the cellular and molecular processes potentially generating tumours from NSCs. Most pro-inflammatory conditions are considered to activate the transcription factor NF-kappaB in various cell types. Strong inductive effects of NF-kappaB on proliferation and migration of NSCs have been described. Moreover, NF-kappaB is constitutively active in most tumour cells described so far. Chronic inflammation is also known to initiate cancer. Thus, NF-kappaB might provide a novel mechanistic link between chronic inflammation, stem cells and cancer. This review discusses the apparently ambivalent role of NF-kappaB: physiological maintenance and repair of the brain via NSCs, and a potential role in tumour initiation. Furthermore, it reveals a possible mechanism of brain tumour formation based on inflammation and NF-kappaB activity in NSCs.