Enzyme-linked immunosorbent assay (ELISA) for the specific detection of apoptotic cells and its application to rapid drug screening

A comprehensive review on anticancer evaluation techniques

The development of effective anticancer strategies and the improvement of our understanding of cancer need analytical tools. Utilizing a variety of analytical approaches while investigating anti-cancer medicines gives us a thorough understanding of the traits and mechanisms concerned to cancer cells, which enables us to develop potent treatments to combat them. The importance of anticancer research may be attributed to various analytical techniques that contributes to the identification of therapeutic targets and the assessment of medication efficacy, which are crucial things in expanding our understanding of cancer biology. The study looks at methods that are often used in cancer research, including cell viability assays, clonogenic assay, flow cytometry, 2D electrophoresis, microarray, immunofluorescence, western blot caspase activation assay, bioinformatics, etc. The fundamentals, applications, and how each technique analytical advances our understanding of cancer are briefly reviewed.

Proteomics-Driven Biomarkers in Pancreatic Cancer

Pancreatic cancer is a devastating disease that has a grim prognosis, highlighting the need for improved screening, diagnosis, and treatment strategies. Currently, the sole biomarker for pancreatic ductal adenocarcinoma (PDAC) authorized by the U.S. Food and Drug Administration is CA 19-9, which proves to be the most beneficial in tracking treatment response rather than in early detection. In recent years, proteomics has emerged as a powerful tool for advancing our understanding of pancreatic cancer biology and identifying potential biomarkers and therapeutic targets. This review aims to offer a comprehensive survey of proteomics' current status in pancreatic cancer research, specifically accentuating its applications and its potential to drastically enhance screening, diagnosis, and treatment response. With respect to screening and diagnostic precision, proteomics carries the capacity to augment the sensitivity and specificity of extant screening and diagnostic methodologies. Nonetheless, more research is imperative for validating potential biomarkers and establishing standard procedures for sample preparation and data analysis. Furthermore, proteomics presents opportunities for unveiling new biomarkers and therapeutic targets, as well as fostering the development of personalized treatment strategies based on protein expression patterns associated with treatment response. In conclusion, proteomics holds great promise for advancing our understanding of pancreatic cancer biology and improving patient outcomes. It is essential to maintain momentum in investment and innovation in this arena to unearth more groundbreaking discoveries and transmute them into practical diagnostic and therapeutic strategies in the clinical context.

HIV-1 Tat Upregulates TREM1 Expression in Human Microglia

Because microglia are a reservoir for HIV and are resistant to the cytopathic effects of HIV infection, they are a roadblock for any HIV cure strategy. We have previously identified that triggering receptor expressed on myeloid cells 1 (TREM1) plays a key role in human macrophage resistance to HIV-mediated cytopathogenesis. In this article, we show that HIV-infected human microglia express increased levels of TREM1 and are resistant to HIV-induced apoptosis. Moreover, upon genetic inhibition of TREM1, HIV-infected microglia undergo cell death in the absence of increased viral or proinflammatory cytokine expression or the targeting of uninfected cells. We also show that the expression of TREM1 is mediated by HIV Tat through a TLR4, TICAM1, PG-endoperoxide synthase 2, PGE synthase, and PGE2-dependent manner. These findings highlight the potential of TREM1 as a therapeutic target to eradicate HIV-infected microglia without inducing a proinflammatory response.

Super-resolution fluorescence microscopic imaging in pathogenesis and drug treatment of neurological disease

Since super-resolution fluorescence microscopic technology breaks the diffraction limit that has existed for a long time in optical imaging, it can observe the process of synapses formed between nerve cells and the protein aggregation related to neurological disease. Thus, super-resolution fluorescence microscopic imaging has significantly impacted several industries, including drug development and pathogenesis research, and it is anticipated that it will significantly alter the future of life science research. Here, we focus on several typical super-resolution fluorescence microscopic technologies, introducing their benefits and drawbacks, as well as applications in several common neurological diseases, in the hope that their services will be expanded and improved in the pathogenesis and drug treatment of neurological diseases.

Advances in Cancer Diagnosis: Bio-Electrochemical and Biophysical Characterizations of Cancer Cells

Cancer is a worldwide leading cause of death, and it is projected that newly diagnosed cases globally will reach 27.5 million each year by 2040. Cancers (malignant tumors), unlike benign tumors are characterized by structural and functional dedifferentiation (anaplasia), breaching of the basement membrane, spreading to adjacent tissues (invasiveness), and the capability to spread to distant sites (metastasis). In the cancer biology research field, understanding and characterizing cancer metastasis as well as features of cell death (apoptosis) is considered a technically challenging subject of study and clinically is very critical and necessary. Therefore, in addition to the cytochemical methods traditionally used, novel biophysical and bioelectrochemical techniques (e.g., cyclic voltammetry and electrochemical impedance spectroscopy), atomic force microscopy, and electron microscopic methods are increasingly being deployed to better understand these processes. Implementing those methods at the preclinical level enables the rapid screening of new anticancer drugs with understanding of their central mechanism for cancer therapy. In this review, principles and basic concepts of new techniques suggested for metastasis, and apoptosis examinations for research purposes are introduced, along with examples of each technique. From our recommendations, the privilege of combining the bio-electrochemical and biosensing techniques with the conventional cytochemical methods either for research or for biomedical diagnosis should be emphasized.

Augmented Therapeutic Potential of EC-Synthetic Retinoids in Caco-2 Cancer Cells Using an In Vitro Approach

Colorectal cancer therapies have produced promising clinical responses, but tumor cells rapidly develop resistance to these drugs. It has been previously shown that EC19 and EC23, two EC-synthetic retinoids, have single-agent preclinical anticancer activity in colorectal carcinoma. Here, isobologram analysis revealed that they have synergistic cytotoxicity with retinoic acid receptor (RAR) isoform-selective agonistic retinoids such as AC261066 (RARβ2-selective agonist) and CD437 (RARγ-selective agonist) in Caco-2 cells. This synergism was confirmed by calculating the combination index (lower than 1) and the dose reduction index (higher than 1). Flow cytometry of combinatorial IC₅₀ (the concentration causing 50% cell death) confirmed the cell cycle arrest at the SubG₀-G₁ phase with potentiated apoptotic and necrotic effects. The reported synergistic anticancer activity can be attributed to their ability to reduce the expression of ATP-binding cassette (ABC) transporters including P-glycoprotein (P-gp1), breast cancer resistance protein (BCRP) and multi-drug resistance-associated protein-1 (MRP1) and Heat Shock Protein 70 (Hsp70). This adds up to the apoptosis-promoting activity of EC19 and EC23, as shown by the increased Caspase-3/7 activities and DNA fragmentation leading to DNA double-strand breaks. This study sheds the light on the possible use of EC-synthetic retinoids in the rescue of multi-drug resistance in colorectal cancer using Caco-2 as a model and suggests new promising combinations between different synthetic retinoids. The current in vitro results pave the way for future studies on these compounds as possible cures for colorectal carcinoma.

Programmed cell death detection methods: a systematic review and a categorical comparison

Programmed cell death is considered a key player in a variety of cellular processes that helps to regulate tissue growth, embryogenesis, cell turnover, immune response, and other biological processes. Among different types of cell death, apoptosis has been studied widely, especially in the field of cancer research to understand and analyse cellular mechanisms, and signaling pathways that control cell cycle arrest. Hallmarks of different types of cell death have been identified by following the patterns and events through microscopy. Identified biomarkers have also supported drug development to induce cell death in cancerous cells. There are various serological and microscopic techniques with advantages and limitations, that are available and are being utilized to detect and study the mechanism of cell death. The complexity of the mechanism and difficulties in distinguishing among different types of programmed cell death make it challenging to carry out the interventions and delay its progression. In this review, mechanisms of different forms of programmed cell death along with their conventional and unconventional methods of detection of have been critically reviewed systematically and categorized on the basis of morphological hallmarks and biomarkers to understand the principle, mechanism, application, advantages and disadvantages of each method. Furthermore, a very comprehensive comparative analysis has been drawn to highlight the most efficient and effective methods of detection of programmed cell death, helping researchers to make a reliable and prudent selection among the available methods of cell death assay. Conclusively, how programmed cell death detection methods can be improved and can provide information about distinctive stages of cell death detection have been discussed.

SMAC mimetics induce autophagy-dependent apoptosis of HIV-1-infected macrophages

Human immunodeficiency type 1 (HIV)-infected macrophages (HIV-Mφ) are a reservoir for latent HIV infection and a barrier to HIV eradication. In contrast to CD4+ T cells, HIV-Mφ are resistant to the cytopathic effects of acute HIV infection and have increased expression of cell survival factors, including X-linked inhibitor of apoptosis (XIAP), baculoviral IAP repeat containing (BIRC) 2/cIAP1, beclin-1, BCL2, BCL-xl, triggering receptor expressed on myeloid cells 1, mitofusin (MFN) 1, and MFN2. DIABLO/SMAC mimetics are therapeutic agents that affect cancer cell survival and induce cell death. We found that DIABLO/SMAC mimetics (LCL-161, AT-406 (also known as SM-406 or Debio 1143), and birinapant) selectively kill HIV-Mφ without increasing bystander cell death. DIABLO/SMAC mimetic treatment of HIV-Mφ-induced XIAP and BIRC2 degradation, leading to the induction of autophagy and the formation of a death-inducing signaling complex on phagophore membranes that includes both pro-apoptotic or necroptotic (FADD, receptor-interacting protein kinase (RIPK) 1, RIPK3, caspase 8, and MLKL) and autophagy (ATG5, ATG7, and SQSTM1) proteins. Genetic or pharmacologic inhibition of early stages of autophagy, but not late stages of autophagy, ablated this interaction and inhibited apoptosis. Furthermore, DIABLO/SMAC mimetic-mediated apoptosis of HIV-Mφ is dependent upon tumor necrosis factor signaling. Our findings thus demonstrate that DIABLO/SMAC mimetics selectively induce autophagy-dependent apoptosis in HIV-Mφ.

BF12, a Novel Benzofuran, Exhibits Antitumor Activity by Inhibiting Microtubules and the PI3K/Akt/mTOR Signaling Pathway in Human Cervical Cancer Cells

BF12 [(2E)-3-[6-Methoxy-2-(3,4,5-trimethoxybenzoyl)-1-benzofuran-5-yl]prop-2-enoic acid], a novel derivative of combretastatin A-4 (CA-4), was previously found to inhibit tumor cell lines, with a particularly strong inhibitory effect on cervical cancer cells. In this study, we investigated the microtubule polymerization effects and apoptosis signaling mechanism of BF12. BF12 showed a potent efficiency against cervical cancer cells, SiHa and HeLa, with IC₅₀ values of 1.10 and 1.06 μm, respectively. The cellular mechanism studies revealed that BF12 induced G2/M phase arrest and apoptosis in SiHa and HeLa cells, which were associated with alterations in the expression of the cell G2/M cycle checkpoint-related proteins (cyclin B1 and cdc2) and alterations in the levels of apoptosis-related proteins (P53, caspase-3, Bcl-2, and Bax) of these cells, respectively. Western blot analysis showed that BF12 inhibited the PI3 K/Akt/mTOR signaling pathway and induced apoptosis in human cervical cancer cells. BF12 was identified as a tubulin polymerization inhibitor, evidenced by the effective inhibition of tubulin polymerization and heavily disrupted microtubule networks in living SiHa and HeLa cells. By inhibiting the PI3 K/Akt/mTOR signaling pathway and inducing apoptosis in human cervical cancer cells, BF12 shows promise for use as a microtubule inhibitor.

TREM-1 Protects HIV-1-Infected Macrophages from Apoptosis through Maintenance of Mitochondrial Function

The major challenge to human immunodeficiency virus (HIV) treatment is the development of strategies that lead to viral eradication. A roadblock to accomplishing this goal is the lack of an approach that would safely eliminate HIV from all resting/latent reservoirs, including macrophages. Macrophages are a key part of the innate immune system and are responsible for recognizing invading microbes and sending appropriate signals to other immune cells. Here, we found that HIV induces the upregulation of the protein TREM1 (triggering receptor expressed on myeloid cells 1), which signals an increase in the expression of antiapoptotic proteins, thus promoting survival of HIV-infected macrophages.

Macrophages are a reservoir for latent human immunodeficiency type 1 (HIV) infection and a barrier to HIV eradication. In contrast to CD4⁺ T cells, macrophages are resistant to the cytopathic effects of acute HIV infection. Emerging data suggest a role for TREM1 (triggering receptor expressed on myeloid cells 1) in this resistance to HIV-mediated cytopathogenesis. Here, we show that upon HIV infection, macrophages increase the expression of BCL2, BCLXL, TREM1, mitofusin 1 (MFN1), and MFN2 and the translocation of BCL2L11 (BIM) to the mitochondria and decrease the expression of BCL2-associated agonist of cell death (BAD) and BAX while maintaining a 95% survival rate over 28 days. The HIV proteins Tat and gp120 and the GU-rich single-stranded RNA (ssRNA) (RNA40) from the HIV long terminal repeat region (and a natural Toll-like receptor 8 [TLR8] agonist) induced similar effects. TREM1 silencing in HIV-infected macrophages led to decreased expression of BCL2, BCLXL, MFN1, and MFN2 and increased expression of BAD and BAX. This correlated with a significant increase in apoptosis mediated by a disruption of the mitochondrial membrane potential (Δψm), leading to the release of cytochrome c and caspase 9 cleavage. Exposure of TREM1-silenced macrophages to Tat, gp120, or RNA40 similarly resulted in the disruption of Δψm, cytochrome c release, caspase 9 cleavage, and apoptosis. Thus, our findings identify a mechanism whereby HIV promotes macrophage survival through TREM1-dependent upregulation of BCL2 family proteins and mitofusins that inhibits BCL2L11-mediated disruption of Δψm and subsequent apoptosis. These findings indicate that TREM1 can be a useful target for elimination of the HIV reservoir in macrophages.

Rapid Detection of Severe Fever with Thrombocytopenia Syndrome Virus via Colloidal Gold Immunochromatography Assay

To develop the point-of-care testing method to facilitate the clinical detection of severe fever with thrombocytopenia syndrome virus (SFTSV), colloidal gold paper-based lateral flow immunochromatography test strips (LFITSs) have been fabricated for the rapid detection for the first time. The pH value and the amount of monoclonal antibody to prepare colloidal gold nanoparticle-labeled monoclonal antibody bioconjugates were optimized. In addition, 0.4% bovine serum albumin was considered to be the best concentration for blocking nitrocellulose membranes. Under optimal conditions, the limit of detection for SFTSV was as low as 1 ng/mL depending on a visual line. Meanwhile, the entire detection process required no more than 10 min with a volume of only 50 μL of the analyte solution. Moreover, paper-based LFITSs were evaluated in real samples of human serum of patients with satisfactory results. In addition, all strips were of high stability and specificity. In the light of advantages such as simple, portable, rapid, and low cost, the developed LFITSs will extensively come into service, especially in remote areas.

Structural-based design, synthesis, and antitumor activity of novel alloxazine analogues with potential selective kinase inhibition

Protein kinases are promising therapeutic targets for cancer therapy. Here, we applied multiple approaches to optimize the potency and selectivity of our reported alloxazine scaffold. Flexible moieties at position 2 of the hetero-tricyclic system were incorporated to fit into the ATP binding site and extend to the adjacent allosteric site and selectively inhibit protein kinases. This design led to potential selective inhibition of ABL1, CDK1/Cyclin A1, FAK, and SRC kinase by 30-59%. Cytotoxicity was improved by ∼50 times for the optimized lead (10b; IC₅₀ = 40 nM) against breast cancer (MCF-7) cells. Many compounds revealed potential cytotoxicity against ovarian (A2780) and colon carcinoma (HCT116) cells of ∼10-30 time improvement (IC₅₀ 5-17 nM). The results of the Annexin-V/PI apoptotic assay demonstrated that many compounds induced significantly early (89-146%) and a dramatically late (556-1180%) cell death in comparison to the vehicle control of MCF-7 cells. SAR indicated that 5-deazaalloxazines have a higher selectivity for Abl-1 and FAK kinases than alloxazines. The correlations between GoldScore fitness into FAK and SRC kinases and IC₅₀ against MCF-7 and A2780 cells were considerable (R²: 0.86-0.98).

miR-495 inhibits proliferation, migration, and invasion and induces apoptosis via inhibiting PBX3 in melanoma cells

Background

Amounting evidence indicate that miRNAs play an important role in the development of various cancers. MiR-495 is a potential tumor suppressor in cancers, however its role in melanoma is still elusive. The study aimed to investigate the role of miR-495 and the underlying mechanisms in melanoma cells.

Methods

The levels of miR-495 in melanoma tissues and cell lines were measured by quantitative real-time polymerase chain reaction. Mimics of miR-495 was transfected into human melanoma cells A375 and MeWo. Cell viability of miR-495-transfected cells was assayed by MTT assay. Cell migration and invasion of miR-495 transfected cells were measured by wound healing assay and transwell assay, respectively. Nucleosome enzyme-linked immunosorbent assay was performed to measure the apoptosis induced by overexpression of miR-495. Luciferase reporter assays were performed to verify the interaction between miR-495 and its target PBX3.

Results

It was found that the expression levels of miR-495 were down-regulated in melanoma tissues and cells. Moreover, overexpression of miR-495 inhibited melanoma cell proliferation, migration and invasion in vitro. PBX3 was identified as a target for inhibition by miR-495 and was confirmed by luciferase assay, quantitative real-time polymerase chain reaction and western blot. We also indicated that silencing of PBX3 also repressed melanoma cell proliferation, migration and invasion in vitro.

Conclusion

In summary, our findings demonstrated that miR-495 functions as a tumor suppressor in human melanoma via directly targeting PBX3.

Induction of autophagy by PI3K/MTOR and PI3K/MTOR/BRD4 inhibitors suppresses HIV-1 replication

In this study, we investigated the effects of the dual phosphatidylinositol 3-kinase/mechanistic target of rapamycin (PI3K/MTOR) inhibitor dactolisib (NVP-BEZ235), the PI3K/MTOR/bromodomain-containing protein 4 (BRD4) inhibitor SF2523, and the bromodomain and extra terminal domain inhibitor JQ1 on the productive infection of primary macrophages with human immunodeficiency type-1 (HIV). These inhibitors did not alter the initial susceptibility of macrophages to HIV infection. However, dactolisib, JQ1, and SF2523 all decreased HIV replication in macrophages in a dose-dependent manner via degradation of intracellular HIV through autophagy. Macrophages treated with dactolisib, JQ1, or SF2523 displayed an increase in LC3B lipidation combined with SQSTM1 degradation without inducing increased cell death. LC3B-II levels were further increased in the presence of pepstatin A suggesting that these inhibitors induce autophagic flux. RNA interference for ATG5 and ATG7 and pharmacological inhibitors of autophagosome-lysosome fusion and of lysosomal hydrolases all blocked the inhibition of HIV. Thus, we demonstrate that the mechanism of PI3K/MTOR and PI3K/MTOR/BRD4 inhibitor suppression of HIV requires the formation of autophagosomes, as well as their subsequent maturation into autolysosomes. These data provide further evidence in support of a role for autophagy in the control of HIV infection and open new avenues for the use of this class of drugs in HIV therapy.

Long non-coding RNA 00312 downregulates cyclin B1 and inhibits hepatocellular carcinoma cell proliferation in vitro and in vivo

Long non-coding RNAs are dysregulated in human hepatocellular carcinoma (HCC). We tested the potential effect of long non-coding RNA 00312 ("Lnc00312") on human HCC cell behavior in vitro and in vivo. Forced-expression of Lnc00312 by a lentiviral vector induced proliferation inhibition and apoptosis in HepG2 cells and primary human HCC cells. Lnc00312 downregulated cyclin B1 and induced G2-M cell cycle arrest in HCC cells. Restoring cyclin B1 expression by a cyclin B1 cDNA construct inhibited Lnc00312-induced cytotoxicity against HCC cells. Conversely, siRNA-mediated knockdown of Lnc00312 increased cyclin B1 expression and promoted HepG2 cell proliferation. In vivo, the growth of HepG2 xenograft tumors in severe combined immunodeficient (SCID) mice was largely inhibited after expression of Lnc00312. Significantly, Lnc00312 is downregulated in human HCC tissues, which is negatively correlated with the tumor grade. Overall, Lnc00312 inhibits human HCC cell proliferation in vitro and in vivo. Cyclin B1 could be a key target protein of Lnc00312 in human HCC cells.

SphK2 over-expression promotes osteosarcoma cell growth

It is needed to explore novel biological markers for early diagnosis and treatment of human osteosarcoma. Sphingosine kinase 2 (SphK2) expression and potential functions in osteosarcoma were studied. We demonstrate that SphK2 is over-expressed in multiple human osteosarcoma tissues and established human osteosarcoma cell lines. Silence of SphK2 by targeted-shRNAs inhibited osteosarcoma cell growth, and induced cell apoptosis. On the other hand, exogenous over-expression of SphK2 could further promote osteosarcoma cell growth. Notably, microRNA-19a-3p ("miR-19a-3p") targets the 3' UTR (untranslated region) of SphK2 mRNA. Remarkably, forced-expression of miR-19a-3p silenced SphK2 and inhibited osteosarcoma cell growth. In vivo, SphK2 silence, by targeted-shRNA or miR-19a-3p, inhibited U2OS tumor growth in nude mice. These results suggest that SphK2 could be a novel and key oncotarget protein for OS cell progression.

The preclinical analysis of TW-37 as a potential anti-colorectal cancer cell agent

TW-37 is a novel, potent and non-peptide Bcl-2 small-molecule inhibitor. Its activity in colorectal cancer (CRC) cells is studied. In both HCT-116 cells and primary human colon cancer cells, treatment with TW-37 at only nM concentration efficiently inhibited cell survival and proliferation. TW-37 also induced caspase-3/9 and apoptosis activation in CRC cells. Feedback autophagy activation was observed in TW-37-treated CRC cells. Reversely pharmacological autophagy inhibition or Beclin-1 knockdown by targeted-shRNA potentiated TW-37-induced apoptosis and killing of CRC cells. In vivo, intravenous injection of TW-37 inhibited HCT-116 tumor growth in mice. TW-37’s anti-tumor activity was further potentiated against Beclin-1-silenced HCT-116 tumors. Together, targeting Bcl-2 family protein by TW-37 efficiently inhibits CRC cell growth in vitro and in vivo. Inhibition of feedback autophagy activation could further sensitize TW-37.

Activation of AMPK by OSU53 protects spinal cord neurons from oxidative stress

The present study tested the potential effect of OSU53, a novel AMPK activator, against hydrogen peroxide (H2O2)-induced spinal cord neuron damages. Treatment with OSU53 attenuated H2O2-induced death and apoptosis of primary murine spinal cord neurons. OSU53 activated AMPK signaling, which is required for its actions in spinal cord neurons. The AMPK inhibitor Compound C or AMPKα1 siRNA almost abolished OSU53-mediated neuroprotection against H2O2. On the other hand, sustained-activation of AMPK by introducing the constitutive-active AMPKα1 mimicked OSU53's actions, and protected spinal cord neurons from oxidative stress. OSU53 significantly attenuated H2O2-induced reactive oxygen species production, lipid peroxidation and DNA damages in spinal cord neurons. Additionally, OSU53 increased NADPH content and heme oxygenase-1 mRNA expression in H2O2-treated spinal cord neurons. Together, we indicate that targeted-activation of AMPK by OSU53 protects spinal cord neurons from oxidative stress.

The Cytotoxic and Apoptotic Effects of Scrophularia Atropatana Extracts on Human Breast Cancer Cells

Purpose: Breast cancer is the most frequent malignancy diagnosed in women both in developed and developing countries. Natural products especially those from herbal origin have high potential in producing drug components with a source of novel structures. The present study was designed to explore the cytotoxic effects and the cell death mechanism of Scrophularia atropatana extracts. Methods: MTT assay was employed to evaluate the cytotoxic activity of the extracts of S. atropatana on the MCF-7 as well as non-malignant cells. Furthermore, induction of apoptosis was evaluated by TUNEL assay, cell death detection ELISA, DNA fragmentation test, western blotting and Real Time PCR. Results: In vitro exposures of the MCF-7 cells with different concentration of S. atropatana extract significantly inhibited their growth and viability and induced apoptosis in the MCF-7 cells. Cleavage PARP protein, decrease in the mRNA expression levels of bcl-2 and increase expression of Caspase-3 and Caspase-9 mRNA, highlights that the induction of apoptosis was the main mechanism of cell death. Moreover the expression study of Caspase-9 mRNA showed that, the extracts have induced apoptosis via intrinsic mitochondrial pathway. Conclusion: Our results demonstrated that dichloromethane extract of Scrophularia atropatana has an apoptotic effects and it can be developed as anticancer agents.

Hyaluronic Acid Nanohydrogel Loaded With Quercetin Alone or in Combination to a Macrolide Derivative of Rapamycin RAD001 (Everolimus) as a New Treatment for Hormone-Responsive Human Breast Cancer

The aim of this study is based on the evaluation of anticancer, anti-inflammatory activities, and cellular uptake of hyaluronic acid nanohydrogel of quercetin tested alone and in combination to a macrolide derivative of rapamycin RAD001 (everolimus) on hormone-responsive breast cancer cell line MCF-7. Biological investigations were focused on the receptor mediated cellular internalization of the nanohydrogel and its abilities to reduce secretion of several cytokines (IL-8, IL-6, IL-19), VEGF, and metalloproteases (MMP-2, MMP-9) under pro-inflammatory conditions. Nanohydrogel show a CD44 dependent endocytosis with evident time dependent cytoplasmatic accumulation with abilities to reduce secretion of all cytokines of ∼60% compared to untreated cells. Combination of formulated quercetin and everolimus leads to a synergistic cytotoxic effects with a Combination Index of 0.38. These results highlights the importance of synergistic effect of the hyaluronic acid nanohydrogel of quercetin with everolimus in the regulation of human breast cancer cell proliferation and emphasize the antitumor and anti-inflammatory properties of the nanocarrier. J. Cell. Physiol. 232: 2063-2074, 2017. © 2016 Wiley Periodicals, Inc.

Growth-Inhibitory and Apoptosis-Inducing Effects of Punica granatum L. var. spinosa (Apple Punice) on Fibrosarcoma Cell Lines

PURPOSE

Punica granatum L. var. granatum (Pomegranate), an herbaceous plant found in Iran, The aim of this study was to investigate the cytotoxic effects, induction of apoptosis, and the mechanism of cell death of ethanol extract from Punica granatum L. var. spinosa on the mouse fibrosarcoma cell line, WEHI-164.

METHODS

Various parts of the herbs were extracted from fruit using ethanol as the solvent, and the cytotoxicity and cell viability of the ethanolic extract were determined by the MTT assay. To determine whether necrosis or apoptosis is the predominant cause of cell death, cell death detection was performed using the ELISA method. The induction of apoptosis was confirmed using the terminal deoxynucleotidyl transferase- (TdT-) mediated dUTP nick end labeling (TUNEL) assay. Moreover, a sensitive immunoblotting technique was used to examine the production of Caspase-3 and Bcl2 proteins.

RESULTS

Our findings suggested that the ethalonic extract of Punica granatum L. var. spinosa altered cell morphology, decreased cell viability, suppressed cell proliferation and induced cell death in a time- and dose-dependent manner in WEHI-164 cells (IC50 = 229.024μg/ml), when compared to a chemotherapeutic anticancer drug, Toxol (Vesper Pharmaceuticals), with increased nucleosome production from apoptotic cells. Induction of apoptosis by the plant extract was proved by the decrease of pro-Caspase-3 and Bcl2 proteins and quantitatively confirmed by Immunoblotting analysis.

CONCLUSION

The results obtained from the present study have demonstrated the growth-inhibitory effect of Ethanol Extracts from Punica granatum L. var. spinosa, and clearly showed that apoptosis was the major mechanism of in-vitro cell death induced by the extract.

Autophagy induction by histone deacetylase inhibitors inhibits HIV type 1

Histone deacetylase inhibitors (HDACi) are being evaluated in a "shock-and-kill" therapeutic approach to reverse human immunodeficiency virus type-1 (HIV) latency from CD4(+) T cells. Using this approach, HDACi have induced HIV RNA synthesis in latently infected cells from some patients. The hope is that the increase in viral production will lead to killing of the infected cell either by the virus itself or by the patient's immune system, a "sterilizing cure." Although administered within the context of combination antiretroviral therapy, the infection of bystander cells remains a concern. In this study, we investigated the effect of HDACi (belinostat, givinostat, panobinostat, romidepsin, and vorinostat) on the productive infection of macrophages. We demonstrate that the HDACi tested do not alter the initial susceptibility of macrophages to HIV infection. However, we demonstrate that HDACi decrease HIV release from macrophages in a dose-dependent manner (belinostat < givinostat < vorinostat < panobinostat < romidepsin) via degradation of intracellular HIV through the canonical autophagy pathway. This mechanism involves unc-51-like autophagy-activating kinase 1 (ULK1) and the inhibition of the mammalian target of rapamycin and requires the formation of autophagosomes and their maturation into autolysosomes in the absence of increased cell death. These data provide further evidence in support of a role for autophagy in the control of HIV infection and suggest that careful consideration of off-target effects will be essential if HDACi are to be a component of a multipronged approach to eliminate latently infected cells.

Induction of Apoptosis and Cytotoxic Activities of Iranian Orthodox Black Tea Extract (BTE) Using in vitro Models

PURPOSE

Plant-derivate therapeutic agents can perform cancer chemotherapeutic activity through triggering apoptotic cell death. Our aim was to investigate the cytotoxic effects, induction of apoptosis, and the mechanism of cell death of Iranian orthodox black tea extracts (BTEs) and hydro methanolic purified fractions (40, 60, 80 and 100%) in KB cells (oral squamous cell carcinoma).

METHODS

In order to analyze the cytotoxic activity of the BTEs, MTT (3-(4, 5- dimetylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide) and Trypan-blue assays were performed in oral squamous cell carcinoma (KB). Furthermore, the apoptosis inducing action of the extracts was determined by TUNEL, DNA fragmentation and cell death detection analysis.

RESULTS

Dichloromethane BTE and hydro methanol fractions (40 and 60%) extract showed no cytotoxic effects; however, hydro methanol crude and hydro methanol fractions of BTE (80 and 100%) significantly inhibited cell growth and viability in a dose and time dependent manner. In addition, Cell death assay, TUNEL, and DNA fragmentation indicated induction of apoptosis by hydro methanol 80 and 100% fractions of BTE in KB cells. Statistical significance was determined by analysis of variance (ANOVA), followed by Duncan test and p value ≤0.05 was considered significant.

CONCLUSION

The results from the present study suggests that the hydro methanol crude and hydro methanol fractions of BTE (80 and 100%) are significant source of compounds with the anti proliferative and cytotoxic activities, and this may be useful for developing potential chemo preventive substances.

Induction of apoptosis by grape seed extract (Vitis vinifera) in oral squamous cell carcinoma

Development of novel therapeutic modalities is crucial for the treatment of oral squamous cell carcinoma (OSCC). Recent scientific studies have been focused on herbal medicines as potent anti-cancer drug candidates. This study is the first to investigate the cytotoxic effects and the mechanism of cell death induced by grape seed extract (GSE) in oral squamous cell carcinoma (KB cells). MTT (3-(4,5-dimetylthiazol-2-yl)-2,5 diphenyltetrazolium bromide) and trypan blue assays were performed in KB cells as well as human umbilical vein endothelial cells (HUVEC) were used to analyze the cytotoxic activity of GSE. Furthermore, the apoptosis-inducing action of the extract was determined by TUNEL, DNA fragmentation and cell death analysis. Statistical significance was determined by analysis of variance (ANOVA), followed by Duncan's test at a significance level of P≤0.05. The results showed apoptotic potential of GSE, confirmed by significant inhibition of cell growth and viability in a dose- and time- dependent manner without inducing damage to non-cancerous cell line HUVEC. The results of this study suggest that this plant contains potential bioactive compound(s) for the treatment of oral squamous cell carcinoma.

Inhibitory and cytotoxic activities of salvia officinalis L. Extract on human lymphoma and leukemia cells by induction of apoptosis

PURPOSE

Salvia officinalis L., also known as Maryam Goli, is one of the native plants used to Persian medicinal herbs. Hence, the objective of this study was to examine the in vitro cytotoxic activities of a standardized crude methanol extracts prepared from Salvia officinalis L., on a non-Hodgkin's B-cell lymphoma (Raji) and human leukemic monocyte lymphoma (U937), Human acute myelocytic leukemia (KG-1A) and Human Umbilical Vein Endothelial (HUVEC) cell lines.

METHODS

The effect of methanolic extract on the inhibition of cell proliferation and cytotoxic activity was evaluated by Dye exclusion and Micro culture tetrazolium test (MTT) cytotoxicity assay. Cell death ELISA was employed to quantify the nucleosome production result from nuclear DNA fragmentation during apoptosis and determined whether the mechanism involves induction of apoptosis or necrosis.

RESULTS

The present results demonstrated that methanolic extract at 50 to 800 μg/ml dose and time-dependently suppressed the proliferation of KG-1A, U937 and Raji cells by more than 80% (p<0.01), with ascending order of IC50 values in 24: KG-1A (214.377 μg/ml), U937 (229.312 μg/ml) and Raji (239.692 μg/ml) when compared with a chemotherapeutic anticancer drug, paclitaxel (Toxol), confirming the tumour-selective cytotoxicity. The crude extract however did not exert any significant cytotoxic effect on normal cell line HUVEC (IC50>800 Ag/ml). Nucleosome productions in KG-1A, Raji and U937 cells were significantly increased respectively upon the treatment of Salvia officinalis L. extract.

CONCLUSION

The Salvia officinalis L. extract was found dose and time-dependently inhibits the proliferation of lymphoma and leukemic cells possibly via an apoptosis-dependent pathway.

Inhibition of Growth and Induction of Apoptosis in Fibrosarcoma Cell Lines by Echinophora platyloba DC: In Vitro Analysis

Echinophora platyloba DC plant (Khousharizeh) is one of the indigenous medicinal plants which is used as a food seasoning and medicine in Iran. The objective of this study was to examine the in vitro cytotoxic activity and the mechanism of cell death of crude methanolic extracts prepared from Echinophora platyloba DC, on mouse fibrosarcoma cell line (WEHI-164). Cytotoxicity and viability of methanolic extract was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and dye exclusion assay. Cell death ELISA was employed to quantify the nucleosome production result from nuclear DNA fragmentation during apoptosis and determine whether the mechanism involves induction of apoptosis or necrosis. The cell death was identified as apoptosis using terminal deoxynucleotidyl transferase- (TdT-) mediated dUTP nick end labeling (TUNEL) assay. Our results demonstrated that the extract decreased cell viability, suppressed cell proliferation, and induced cell death in a time- and dose-dependent manner in WEHI-164 cells (IC50 = 196.673 ± 12.4 μg/mL) when compared with a chemotherapeutic anticancer drug, Toxol. Observation proved that apoptosis was the major mechanism of cell death. So the Echinophora platyloba DC extract was found to time- and dose-dependently inhibit the proliferation of fibrosarcoma cell possibly via an apoptosis-dependent pathway.

Synchronizing cell cycle of goat fibroblasts by serum starvation causes apoptosis

Cell cycle stage and synchronization of donor cells are important factors influencing the success of somatic cell nuclear transfer. This study examined whether serum starvation has any effect on specific cell death. We also studied the effects of serum starvation, culture to confluence, and full confluency (confluent + 72 h) on cell cycle characteristics and apoptosis of goat dermal fibroblast cells. The cells were obtained from the ear of a 1.5-year-old female goat. The following experimental groups were analysed for fibroblast cells: (i) normally growing, (ii) confluent, (iii) full confluency, (iv) cells starved for 48 h and (v) cells starved for 72 h. Analysis of cell cycle distribution by flow cytometry showed that 4.56 and 51.88% of normal cycling cells were at the G0 and G1 phases respectively. In the confluent group, 80% of the cells were arrested in the G0/G1 phase. Serum starvation for 48 and 72 h arrested 84.78% and 90.1% cells at the G0/G1 phase respectively which showed a significant difference when compared with the control group (p < 0.05). Double staining by PI and FITC distinguishes G0 phase from G1 phase. In the full confluency group, 91.53% of cells were at G0/G1 stage, but in contrast to the serum starved group, this high percentage of G0/G1 cells was mainly associated with G1 cells. Under normal culture conditions, 6.39% of cells underwent early apoptosis. In the confluent group 8.93% of cells showed early apoptosis. Serum starvation for 48 and 72 h caused early apoptosis in 8.91 and 39.83% of the cells respectively. Full confluency treatment did not increase the number of apoptotic cells significantly (8.67%). After 72 h, serum starvation significantly increased early apoptosis (p < 0.05). In conclusion, the use of full confluency is suitable for cell cycle synchronization because it arrests cells at the G0/G1 phase and also induces less apoptosis in comparison with the serum starvation group.

Differential induction of rat neuronal excitotoxic cell death by human immunodeficiency virus type 1 clade B and C tat proteins

In the absence of effective antiretroviral therapy, infection with clade B human immunodeficiency virus (HIV-1) infection commonly progresses to AIDS dementia. However, in India, where clade C infection is most prevalent, severe cognitive impairment due to HIV-1 is reported to be less prevalent. The Tat protein of HIV-1, which is released from HIV-1-infected macrophages, is thought to play a major role in the disruption of neuronal function as well as in the infiltration of macrophages associated with advanced neuropathogenesis. Clade B Tat is excitotoxic to hippocampal neurons by potentiating N-methyl-d-aspartate-induced currents of the zinc-sensitive NR1/NR2A N-methyl-d-aspartate receptor in a zinc-binding-dependent mechanism. This study characterizes the zinc-binding properties of clade C Tat protein. Using ultraviolet spectroscopy and the Ellman reaction, we show that clade C Tat protein binds just one zinc ion per monomer. We then investigated the ability of clade C Tat to block the inhibition of N-methyl-d-aspartate receptors from zinc antagonism through ion chelation. Although clade C Tat enhanced N-methyl-d-aspartate-mediated rat hippocampus neuronal toxicity in the presence of zinc, the increase was significantly less than that observed with clade B Tat. These findings suggest that the observed differences in neuropathogenesis found with HIV-1 clade C infection compared to clade B may, in part, be due to a decrease in Tat-mediated neurotoxicity.

Hormonally active vitamin D3 (1alpha,25-dihydroxycholecalciferol) triggers autophagy in human macrophages that inhibits HIV-1 infection

Autophagy is a self-digestion pathway essential for maintaining cellular homeostasis and cell survival and for degrading intracellular pathogens. Human immunodeficiency virus-1 (HIV-1) may utilize autophagy for replication as the autophagy-related protein-7 (ATG-7), microtubule-associated protein 1 light chain 3, ATG-12, and ATG-16L2 are required for productive HIV-1 infection; however, the effects of autophagy induction on HIV-1 infection are unknown. HIV-1-infected individuals have lower levels of 1α,25-dihydroxycholecalciferol, the hormonally active form of vitamin D, than uninfected individuals. with the lowest concentrations found in persons with AIDS. Using human macrophages and RNA interference for ATG-5 and Beclin-1 and chemical inhibition of phosphatidylinositol 3-kinase, we have found that physiologically relevant concentrations of 1α,25-dihydroxycholecalciferol induce autophagy in human macrophages through a phosphatidylinositol 3-kinase-, ATG-5-, and Beclin-1-dependent mechanism that significantly inhibits HIV-1 replication in a dose-dependent manner. We also show that the inhibition of basal autophagy inhibits HIV-1 replication. Furthermore, although 1α,25-dihydroxycholecalciferol induces the secretion of human cathelicidin, at the concentrations produced in vitro, cathelicidin does not trigger autophagy. Our findings support an important role for autophagy during HIV-1 infection and provide new insights into novel approaches to prevent and treat HIV-1 infection and related opportunistic infections.

Anti-tumor and anti-inflammatory properties of ankaflavin and monaphilone A from monascus purpureus NTU 568

An azaphilonidal derivative monaphilone A (MA) was recently isolated from the fermented products of Monascus purpureus NTU 568 by our laboratory. We report here the exploration of apoptosis-related and anti-inflammatory properties of MA and ankaflavin (AK) by some experiments about inducing death of human laryngeal carcinoma cell line HEp-2 and reducing inflammatory responses on murine macrophage RAW 264.7 cells. We employed a ssDNA enzyme-linked immunosorbent assay (ELISA) kit to investigate the nuclear changes of early apoptosis induced by AK and MA on HEp-2 cells and used a western blot and an enzyme activity assay to demonstrate the activation of caspase-3, caspase-8, and caspase-9 by MA and AK. Our studies revealed that AK and MA may decrease lipopolysaccharide (LPS)-induced inflammatory responses, including nitrite productions and expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) in RAW 264.7 cells. All evidence support that azaphilonidal derivatives from M. purpureus NTU 568, such as AK and MA, are suitable for the development of chemotherapy or chemopreventive agents.

Expression of IFNγR2 mutated in a dileucine internalization motif reinstates IFNγ signaling and apoptosis in human T lymphocytes

In T lymphocytes, the internalization of the R2 chain of the IFN-γ receptor (IFN-γR2) prevents the switching-on of pro-apoptotic and anti-proliferative genes induced by the IFN-γ/STAT1 pathway. In fibroblasts, a critical role of controlling the IFN-γR2 internalization is played by the LI(255-256) intracellular motif. Here we show that, in human malignant T cells, the expression of a mutated IFN-γR2 chain in which the LI(255-256) internalization motif is replaced by two alanines (LI(255-256)AA) induces cell surface accumulation of the receptor and reinstates the cell sensitivity to IFN-γ. In comparison with T cells that expressed wild-type IFN-γR2, cells that expressed the mutated receptor displayed, in response to IFN-γ a sustained activation of STAT1. The activation of this signaling pathway leads to higher induction of MHC class I and FasL expression and triggered apoptosis. Malignant ST4 cells transduced with either wild-type or mutated receptor were able to grow in SCID mice, but only the proliferation of T cells expressing the mutated receptor was inhibited by IFN-γ. Finally, lentiviral-mediated transduction of the mutated receptor in T lymphoblasts from healthy donors reinstated their IFN-γ-dependent apoptosis. As a whole, these data indicate that perturbation of IFN-γR2 internalization by mutating the LI(255-256) motif induces a timely coordinated activation of IFN-γ/STAT1 signaling pathways that leads to the apoptosis of T cells.

Magnetically enhanced high-specificity virus detection using bio-activated magnetic nanoparticles with antibodies as labeling markers

This study describes magnetically driven suppression of cross-reactions among molecules. First, the magnetic nanoparticles are coated with bio-probes and dispersed in liquid. The bio-probes can then bind with homologous or heterologous bio-targets. When alternating-current (ac) magnetic fields are applied, magnetic nanoparticles rotate driven by ac magnetic fields. Thus, the bio-targets bound on the surface of magnetic nanoparticles experience a centrifugal force. The centrifugal force can be manipulated by adjusting the angular frequency of the rotating magnetic nanoparticles. The angular frequency is determined by the applied ac magnetic field frequency. Since the binding force for good binding is much higher than that of poor binding, frequency manipulation is needed for the centrifugal force to be higher than the poor-binding force but lower than the good-binding force. Therefore, poor binding which contributes to cross reactions between molecules can be suppressed efficiently by control of the ac magnetic field frequency.

Pressure: a novel tool for enzyme-linked immunosorbent assay procedure

The enzyme-linked immunosorbent assay (ELISA) technique is the backbone of the diagnostic assay for detection of infectious and allergic diseases. Here, we demonstrate a unique ELISA method for the detection of an antigen or antibody, in which ELISA steps are carried out under pressure instead of conventional thermal incubation. Pressure-mediated ELISA (PELISA), carried out in 1 h shows more than a 2-fold increase in absorbance value than the control experiment carried out at the same time and temperature without applying pressure. Estimation of total IgE by the 1-h PELISA method gives similar absorbance value (1.081±0.031, 823.12 IU) to that obtained by 3-h heat-mediated ELISA on an activated surface (HELISA) (1.165±0.037, 810.96 IU). Since PELISA is sensitive, specific, and reproducible (intra- and interassay CVs were 6.47% and 9.65%, respectively), it could be an excellent alternative to HELISA or conventional ELISA procedures.

Evaluation of synthetic isoflavones on cell proliferation, estrogen receptor binding affinity, and apoptosis in human breast cancer cells

Natural isoflavones have demonstrated numerous pharmacological activities in breast cancer cells, including antiproliferative activities and binding affinities for estrogen receptors (ERs). Chemical modifications on the isoflavone ring system have been prepared and explored for the development of new therapeutics for hormone-dependent breast cancer. The antiproliferative actions of the synthesized isoflavones on MCF-7 and MDA-MB-231 breast cancer cells were examined, as well as cytotoxicity, interaction with estrogen receptors, and proapoptotic activity. The compounds were screened in the absence and in the presence of estradiol to evaluate whether or not estradiol could rescue cell proliferation on MCF-7 cells. Several compounds were able to inhibit cell proliferation in a dose-dependent manner, and compounds containing the bulky 7-phenylmethoxy substituent resulted in cell toxicity not only in MCF-7 cells but also in MDA-MB-231 cells. Selected synthetic isoflavones were able to bind to estrogen receptor with low affinity. Apoptotic pathways were also activated by these compounds in breast cancer cells. The majority of the compounds can bind to both ERs with low affinity, and their effects on hormone-independent breast cancer cells suggest that their ability to inhibit cell growth in breast cancer cells is not exclusively mediated by ERs. Thus, the synthetic trisubstituted isoflavones act on multiple signaling pathways leading to activation of mechanisms of cell-death and ultimately affecting breast cancer cell survival.

Interaction between caspase-8 activation and endoplasmic reticulum stress in glycochenodeoxycholic acid-induced apoptotic HepG2 cells

The accumulation of hydrophobic bile acid, such as glycochenodeoxycholic acid (GCDCA), in the liver has been thought to induce hepatocellular damage in human chronic cholestatic liver diseases. We previously reported that GCDCA-induced apoptosis was promoted by both mitochondria-mediated and endoplasmic reticulum (ER) stress-associated pathways in rat hepatocytes. In this study, we elucidated the relationship between these pathways in GCDCA-induced apoptotic HepG2 cells. HepG2 cells were treated with GCDCA (100-500microM) with or without a caspase-8 inhibitor, Z-IETD-fluoromethyl ketone (Z-IETD-FMK) (30microM) for 3-24h. We demonstrated the presence of both apoptotic pathways in these cells; that is, we showed increases in cleaved caspase-3 proteins, the release of cytochrome c from mitochondria, and the expression of ER resident molecular chaperone Bip mRNA and ER stress response-associated transcription factor Chop mRNA. On the other hand, pretreatment with Z-IETD-FMK significantly reduced the increases, compared with treatment with GCDCA alone. Immunofluorescence microscopic analysis showed that treatment with GCDCA increased the cleavage of BAP31, an integral membrane protein of ER, and pretreatment with Z-IETD-FMK suppressed the increase of caspase-8 and BAP31 cleavage. In conclusion, these results suggest that intact activated caspase-8 may promote and amplify the ER stress response by cleaving BAP31 in GCDCA-induced apoptotic cells.

Preclinical study of a "tailor-made" combination of NK4-expressing gene therapy and gefitinib (ZD1839, Iressa) for disseminated peritoneal scirrhous gastric cancer

We evaluated the effect of a "tailor-made" chemo-gene therapy in scirrhous gastric cancer (SGC)-bearing nude mice. For this tailor-made approach, we first selected gefitinib (epidermal growth factor receptor-tyrosine kinase inhibitor)-sensitive SGC cell lines, and 5/8 cell lines demonstrated various degrees of gefitinib-sensitivity. In the highly gefitinib-sensitive NUGC-4, the biological response to NK4 (HGF antagonist/angiogenesis inhibitor) was examined. Subsequently, the composition of an NK4-expressing ternary complex (cationic lipid/nucleic acid/HMG-1, 2 protein) was optimized for maximum transfection activity in NUGC-4. Finally, mice were peritoneally coinoculated with NUGC-4 and scirrhous-associated gastric fibroblasts, NF22, on day 0. Animal models were orally administrated gefitinib (50 mg/kg/day, on days 7-28), and peritoneally NK4-expressing ternary complex (on days 14, 21 and 28). NK4-expression suppressed the gefitinib-resistance induced by the interaction between fibroblasts and SGC, and eventually, this tailor-made combination synergistically decelerated the disease progression by inhibiting proliferative, angiogenic and antiapoptotic effects in tumor tissues. On day 28, both the hemoglobin concentration (g/dl) (control (n = 8), 11.9; treated (n = 8), 17.3; p = 0.0014) and the numbers of mice in good condition (control, 2; treated, 8; p = 0.0012) were significantly greater, and the abdominal girth (mm) (control, 81.1; treated, 70.3; p = 0.0036) was significantly reduced. The median points of bloody ascite-free survival time (days) (control, 22; treated, 44; p < 0.0001) and time to euthanasia (days) (control, 36.5; treated, 56; p < 0.0001) were also significantly prolonged. This combination is a potentially useful approach to the treatment of peritoneal gefitinib-sensitive SGC dissemination.

Nuclear factor-kappaB p65 small interfering RNA or proteasome inhibitor bortezomib sensitizes head and neck squamous cell carcinomas to classic histone deacetylase inhibitors and novel histone deacetylase inhibitor PXD101

Histone deacetylase inhibitors (HDI) can inhibit proliferation and enhance apoptosis in a wide range of malignancies. However, HDIs show relatively modest activity in head and neck squamous cell carcinomas (HNSCC), in which we have shown the activation of nuclear factor-kappaB (NF-kappaB; NF-kappaB1/RelA or p50/p65), a transcription factor that promotes expression of proliferative and antiapoptotic genes. In this study, we examined if HDIs enhance activation of NF-kappaB and target genes and if genetic or pharmacologic inhibition of NF-kappaB can sensitize HNSCC to HDIs. Limited activity of classic HDIs trichostatin A and sodium butyrate was associated with enhanced activation of NF-kappaB reporter activity in a panel of six HNSCC cell lines. HDIs enhanced NF-kappaB p50/p65 DNA binding and acetylation of the RelA p65 subunit. Transfection of small interfering RNAs targeting p65 strongly inhibited NF-kappaB expression and activation, induced cell cycle arrest and cell death, and further sensitized HNSCC cells when combined with HDIs. The p65 small interfering RNA inhibited HDI-enhanced expression of several NF-kappaB-inducible genes implicated in oncogenesis of HNSCC, such as p21, cyclin D1, and BCL-XL. Bortezomib, an inhibitor of proteasome-dependent NF-kappaB activation, also increased sensitization to trichostatin A, sodium butyrate, and a novel HDI, PXD101, in vitro, and to the antitumor effects of PXD101 in bortezomib-resistant UMSCC-11A xenografts. However, gastrointestinal toxicity, weight loss, and mortality of the combination were dose limiting and required parenteral fluid administration. We conclude that HDI-enhanced NF-kappaB activation is one of the major mechanisms of resistance of HNSCC to HDIs. The combination of HDI and proteasome inhibitor produced increased antitumor activity. Low starting dosages for clinical studies combining HDIs with proteasome inhibitors and IV fluid support may be warranted.

Homocysteine induces mesangial cell apoptosis via activation of p38-mitogen-activated protein kinase

Hyperhomocysteinemia is prevalent among patients with chronic kidney disease (CKD) and has been linked to progressive kidney and vascular diseases. Increased glomerular mesangial cell (MC) turnover, including proliferation and apoptosis, is a hallmark of CKD. Activation of p38-mitogen-activated protein kinase (p38-MAPK) has been linked to apoptosis in many cell lines. Accordingly, we studied the effect of homocysteine (Hcy) on MC p38-MAPK signalling and apoptosis. Hcy (50 microM/24 h) increased MC apoptosis as determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) nick end labelling (TUNEL) and single-stranded DNA (ssDNA) analysis. In addition to increases in pro-caspase-3 protein and caspase-3 activity, cells exposed to Hcy manifested enhanced reactive oxygen species content. Hcy increased p38-MAPK activity (fivefold), with maximal effect at 50 microM and 20 min; p38-MAPK activation was attenuated by N-acetylcysteine (Nac) and catalase (Cat), further indicating that the effect was via oxidative stress. Confocal microscopy revealed activation and nuclear translocation of p38-MAPK that was attenuated by Cat. In addition, Hcy-induced apoptosis as determined by TUNEL and ssDNA assay was abrogated by Nac, Cat, and SB203580 (p38-MAPK inhibitor). We conclude that in MC, Hcy (i) activates p38-MAPK and increases p38MAPK nuclear translocation via an oxidative stress dependent mechanism and (ii) induces DNA damage and apoptosis that is dependent on oxidative stress and p38-MAPK activation.

Combinatorial activation of FAK and AKT by transforming growth factor-beta1 confers an anoikis-resistant phenotype to myofibroblasts

Transforming growth factor-beta (TGF-beta) is a prototypical tumour-suppressor cytokine with cytostatic and pro-apoptotic effects on most target cells; however, mechanisms of its pro-survival/anti-apoptotic signalling in certain cell types and contexts remain unclear. In human lung fibroblasts, TGF-beta1 is known to induce myofibroblast differentiation in association with the delayed activation of focal adhesion kinase (FAK) and protein kinase B (PKB/AKT). Here, we demonstrate that FAK and AKT are independently regulated by early activation of SMAD3 and p38 MAPK, respectively. Pharmacologic or genetic approaches that disrupt SMAD3 signalling block TGF-beta1-induced activation of FAK, but not AKT; in contrast, disruption of early p38 MAPK signalling abrogates AKT activation, but does not alter FAK activation. TGF-beta1 is able to activate AKT in cells expressing mutant FAK or in cells treated with an RGD-containing peptide that interferes with integrin signalling, inhibits FAK activation and induces anoikis (apoptosis induced by loss of adhesion signalling). TGF-beta1 protects myofibroblasts from anoikis, in part, by activation of the PI3K-AKT pathway. Thus, TGF-beta1 co-ordinately and independently activates the FAK and AKT protein kinase pathways to confer an anoikis-resistant phenotype to myofibroblasts. Activation of these pro-survival/anti-anoikis pathways in myofibroblasts likely contributes to essential roles of TGF-beta1 in tissue fibrosis and tumour-promotion.

Interferon receptors and the caspase cascade regulate the antitumor effects of interferons on human pancreatic cancer cell lines

BACKGROUND

Interferons (IFNs) have antiproliferative effects on tumor cells. The apoptotic effects and sensitization to chemotherapy conferred by IFN therapy, however, are not clearly understood. The aims of the present study were to explore the apoptotic effects of IFNs in human pancreatic cancer cell lines and to attempt to define their ability to synergistically enhance sensitivity to 5-fluorouracil (5-FU) and gemcitabine, a mechanism that depends on the expression of IFN receptors.

METHODS

Human pancreatic cancer cells were cultured alone or in combination with the chemotherapeutic agents 5-FU and gemcitabine. Differential dosages of IFN-alpha, -beta, and -gamma were also added to the cell lines concomitantly during a period of 24 to 96 hours. The cell line viability and effects of treatment were examined using the methylthiazol tetrazolium assay and single-stranded DNA apoptosis assay. The expression of IFN receptors was determined using immunohistochemistry. Caspase-8 inhibitor was used to block the caspase cascade.

RESULTS

The antiproliferative and apoptotic effects of IFNs were most profoundly demonstrated on those cells that expressed the respective IFN receptor. The apoptotic effects provided by the interferons, however, were blocked by caspase-8 inhibition. The addition of IFNs significantly enhanced the cytotoxic effects of 5-FU and gemcitabine in those cell lines that expressed the corresponding IFN-alpha, -beta, or -gamma receptors.

CONCLUSIONS

This study on pancreatic cancer cell lines has demonstrated that IFNs mediate apoptosis through IFN receptors and the caspase cascade. Enhanced cytotoxicity occurred when IFNs were combined with 5-FU and gemcitabine.

Divergent role of calcium on Aβ- and MPTP-induced cell death in SK-N-SH neuroblastoma

We attempted to clarify the role of Ca2+ in cell death caused by beta-amyloid protein (Abeta) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in SK-N-SH neuroblastoma, respectively. Two insults both reduced cell viability in a concentration-dependent manner and induced equal cytotoxicity in the presence of 20 microM Abeta and 0.4 mM MPTP for 72 h, respectively (68+/-7 vs. 64+/-6% viability). Time-related study showed that Abeta evoked cell death occurred quickly at 24 h. Relatively, MPTP exhibited a delayed cell death significantly after 72 h of culture. Pretreating the cells with nimodipine and chelating of Ca2+ by EGTA plus 1,2-bis-(O-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) successfully rescued Abeta-induced cell death but failed to prevent MPTP toxicity. ELISA determination of mono/oligonucleosomes accumulation showed the mode of cell death evoked by MPTP was presumably apoptosis while by Abeta was necrosis. SK-N-SH cells constitutively expressed the alpha(1C) subunit of L-type Ca2+ channel and exposure to Abeta or MPTP for 96 h did not further modify its expression. By contrast, alpha(1D) subunit was undetectable or low level expressed in basal condition, but was induced to express after Abeta and MPTP stimulation in a time-dependent manner. Functional assay revealed that KCl-evoked [Ca2+]i rise was significantly greater in Abeta-, but not in MPTP-treated cells when compared with control. Taken together, these results showed that Abeta and MPTP elicited different mode of cell death in SK-N-SH. Nevertheless, Ca2+ overload seems to solely display a crucial role in Abeta-induced cytotoxicity and over-expressed alpha(1D) may contribute to the disruption of cellular Ca2+ homeostasis.