A combined treatment TNF-alpha/doxorubicin alleviates the resistance of MCF-7/Adr cells to cytotoxic treatment

Sesquiterpene dimers with a rare skeleton from Chloranthus holostegius exhibiting multidrug resistance reversal activity in vitro and in vivo

Two previously unreported lindenane sesquiterpene dimers (1 and 2) with a rare skeleton containing an oxaspiro[4.5]decane moiety were isolated from the roots of Chloranthus holostegius var. trichoneurus. Their structures were elucidated by HRESIMS, NMR, ECD, and NMR quantum chemical calculations, along with DP4+ probability analysis. In bioassay, compound 1 exhibited significant activity to reverse the multidrug resistance (MDR)in MCF-7/ADR cells, with an IC50 value of 4.4 μM. Further mechanistic studies revealed that compound 1 combined with doxorubicin could induce apoptosis of MCF-7/ADR cells and block the cell cycle in the G2/M phase. Mechanistically, compound 1 could inhibit the efflux function of P-glycoprotein (P-gp) using the zebrafish model. Finally, the enhanced chemotherapeutic effects of doxorubicin were further confirmed by in vivo zebrafish xenograft experiments.

Signaling controversy and future therapeutical perspectives of targeting sphingolipid network in cancer immune editing and resistance to tumor necrosis factor-α immunotherapy

Anticancer immune surveillance and immunotherapies trigger activation of cytotoxic cytokine signaling, including tumor necrosis factor-α (TNF-α) and TNF-related apoptosis-inducing ligand (TRAIL) pathways. The pro-inflammatory cytokine TNF-α may be secreted by stromal cells, tumor-associated macrophages, and by cancer cells, indicating a prominent role in the tumor microenvironment (TME). However, tumors manage to adapt, escape immune surveillance, and ultimately develop resistance to the cytotoxic effects of TNF-α. The mechanisms by which cancer cells evade host immunity is a central topic of current cancer research. Resistance to TNF-α is mediated by diverse molecular mechanisms, such as mutation or downregulation of TNF/TRAIL receptors, as well as activation of anti-apoptotic enzymes and transcription factors. TNF-α signaling is also mediated by sphingosine kinases (SphK1 and SphK2), which are responsible for synthesis of the growth-stimulating phospholipid, sphingosine-1-phosphate (S1P). Multiple studies have demonstrated the crucial role of S1P and its transmembrane receptors (S1PR) in both the regulation of inflammatory responses and progression of cancer. Considering that the SphK/S1P/S1PR axis mediates cancer resistance, this sphingolipid signaling pathway is of mechanistic significance when considering immunotherapy-resistant malignancies. However, the exact mechanism by which sphingolipids contribute to the evasion of immune surveillance and abrogation of TNF-α-induced apoptosis remains largely unclear. This study reviews mechanisms of TNF-α-resistance in cancer cells, with emphasis on the pro-survival and immunomodulatory effects of sphingolipids. Inhibition of SphK/S1P-linked pro-survival branch may facilitate reactivation of the pro-apoptotic TNF superfamily effects, although the role of SphK/S1P inhibitors in the regulation of the TME and lymphocyte trafficking should be thoroughly assessed in future studies.

Protective effect of nebivolol on doxorubicin-induced cardiotoxicity in rats

INTRODUCTION

The cardiotoxicity of doxorubicin is incompletely understood. We investigated the prophylactic effect of nebivolol on doxorubicin-induced cardiac toxicity.

MATERIAL AND METHODS

Thirty rats were divided into a control group, doxorubicin-treated group and nebivolol + doxorubicin-treated group. The specimens were examined using H + E and Masson's trichrome, caspase 3, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS) and tumor necrosis factor factor-α (TNF-α). The mean area percentage of collagen fiber content, caspase-3, eNOS, iNOS and TNF-α immunoactivities was measured.

RESULTS

The doxorubicin-treated group showed marked myocyte distortion and fragmentation, congestion and cytoplasmic lysis in most fibers. These changes were less intense in the nebivolol-treated group. The mean area percentage of collagen fiber in the nebivolol-treated group was non-significantly smaller (p = 0.07) than that in the doxorubicin-treated group. The expression of caspase-3 (p = 0.03), eNOS (p ≤ 0.001), iNOS (p < 0.001) and TNF-α (p = 0.003) immunoreactivity was improved in the nebivolol-treated group.

CONCLUSIONS

Nebivolol exerted a significant protective effect from doxorubicin toxicity. The protective effect appears to be mediated mainly through caspase-3, eNOS, iNOS and TNF-α modulation.

Cytokine-Induced Killer Cells Modulates Resistance to Cisplatin in the A549/DDP Cell Line

Background Cytokine-induced killer (CIK) cells can potentially enhance the tumor-killing activity of chemotherapy. Objective This study aimed to evaluate the effects of CIK cells on cisplatin (DDP) resistance in the human lung adenocarcinoma cell line A549/DDP. Methods The detect resistance index, drug resistance related-genes and cytokine secretion of A549/DDP co-cultured with CIK cells were assayed in vitro. ResultsAfter A549/DDP co-culture with CIK cells, the DDP resistance of A549/DDP significantly decreased in a time-dependent manner. The DDP resistance of A549/DDP co-cultured with CIK cells for 20 h decreased 4.93-fold compared with that of A549/DDP cells cultured alone (P<0.05). The mRNA and protein expression levels of the glutathione-S-transferase (GST) -π gene in A549/DDP significantly decreased after co-culture with CIK cells (P<0.05). The secretion of interferon (IFN)- γ significantly increased along with the co-culture time of A549/DDP with CIK cells. The expression of GST-π was restored by adding the neutralizing IFN-γ. ConclusionCIK cells can reverse the drug resistance of A549/DDP in a time-dependent manner by reducing GST-π expression to increase the accumulation of DDP. The effect of CIK cells on re-sensitizing lung cancer cells to the chemotherapy drug was partially dependent on the secretion of IFN-γ.

Doxorubicin effect is enhanced by sphingosine-1-phosphate signaling antagonist in breast cancer

BACKGROUND

Doxorubicin is one of the most commonly used chemotherapeutic drugs for breast cancer; however, its use is limited by drug resistance and side effects. We hypothesized that adding FTY720, a sphingosine-1-phosphate (S1P) receptor functional antagonist, to doxorubicin would potentiate its effects by suppression of drug-induced inflammation.

MATERIALS AND METHODS

The Cancer Genome Atlas, Gene Expression Omnibus data sets, and National Cancer Institute-60 panel were used for gene expressions and gene set enrichment analysis. E0771 syngeneic mammary tumor cells were used. OB/OB mice fed with western high-fat diet were used as an obesity model.

RESULTS

STAT3 expression was significantly increased after doxorubicin treatment in human breast cancer that implicates that doxorubicin evokes inflammation. Expression of sphingosine kinase 1, the enzyme that produces S1P and links inflammation and cancer, tended to be higher in doxorubicin-resistant human cancer and cell lines. In a murine breast cancer model, sphingosine kinase 1, S1P receptor 1, interleukin 6, and STAT3 were overexpressed in the doxorubicin-treated group, whereas all of them were significantly suppressed with addition of FTY720. Combination therapy synergistically suppressed cancer growth both in vitro and in vivo. Furthermore, combination therapy showed higher efficacy in an obesity breast cancer model, where high body mass index demonstrated trends toward worse disease-free and overall survival, and high-serum S1P levels in human patients and volunteers.

CONCLUSIONS

We found that FTY720 enhanced the efficacy of doxorubicin by suppression of drug-induced inflammation, and combination therapy showed stronger effect in obesity-related breast cancer.

Inhibition of Akt phosphorylation attenuates resistance to TNF-α cytotoxic effects in MCF-7 cells, but not in their doxorubicin resistant derivatives

Objective(s):

Acquisition of TNF-α resistance plays role in the onset and growth of malignant tumors. Previous studies have demonstrated that MCF-7 cell line and its doxorubicin resistant variant MCF-7/Adr are resistant against the cytotoxic effects of TNF-α. In this study, we investigated the role of Akt activation in resistance of MCF-7 and MCF-7/Adr against TNF-α cytotoxicity.

Materials and Methods:

The role of Akt activation in TNF-α cytotoxicity was investigated by MTT cell viability assay following treatment of the cells with the chemical inhibitor of Akt activation with or without TNF-α treatment. Phosphorylation of Akt at Ser473 before and after 72 hr TNF-α treatment was also determined by western blot.

Results:

TNF-α treatment led to enhancement of Akt Ser473 phosphorylation. Treatment of MCF-7 cells with TNF-α along with Akt-inhibitor agent, tricribine, attenuated Akt Ser473 phosphorylation and sensitized these cells to the cytotoxic effects of TNF-α in a dose and time dependent manner while tricribine treatment did not cause any significant cytotoxicity in MCF-7/Adr cells alone or in combination with TNF-α.

Conclusion:

These results demonstrate that Akt phosphorylation plays pivotal role in the resistance of MCF-7 cells against TNF-α-induced cytotoxicity while it might play no significant role in the resistance of MCF-7/Adr cells against TNF-α.

Enhanced Cellular Internalization and On-Demand Intracellular Release of Doxorubicin by Stepwise pH-/Reduction-Responsive Nanoparticles

The efficient delivery of antitumor agents to tumor sites faces numerous obstacles, such as poor cellular uptake and slow intracellular drug release. In this regard, smart nanoparticles (NPs) that respond to the unique microenvironment of tumor tissues have been widely used for drug delivery. In this study, novel charge-reversal and reduction-responsive histidine-grafted chitosan-lipoic acid NPs (HCSL-NPs) were selected for efficient therapy of breast cancer by enhancing cell internalization and intracellular pH- and reduction-triggered doxorubicin (DOX) release. The surface charge of HCSL-NPs presented as negative at physiological pH and reversed to positive at the extracellular and intracellular pH of the tumor. In vitro release investigation revealed that DOX/HCSL-NPs demonstrated a sustained drug release under the physiological condition, whereas rapid DOX release was triggered by both endolysosome pH and high-concentration reducing glutathione (GSH). These NPs exhibited enhanced internalization at extracellular pH, rapid intracellular drug release, and improved cytotoxicity against 4T1 cells in vitro. Excellent tumor penetrating efficacy was also found in 4T1 tumor spheroids and solid tumor slices. In vivo experiments demonstrated that HCSL-NPs exhibited excellent tumor-targeting ability in tumor tissues as well as excellent antitumor efficacy and low systemic toxicity in breast tumor-bearing BALB/c mice. These results indicated that the novel charge-reversal and reduction-responsive HCSL-NPs have great potential for targeted and efficient delivery of chemotherapeutic drugs in cancer treatments.

MALDI-MS Patterning of Caspase Activities and Its Application in the Assessment of Drug Resistance

Mass spectrometry (MS) has been widely used for enzyme activity assays. Herein, we propose a MALDI-MS patterning strategy for the convenient visual presentation of multiple enzyme activities with an easy-to-prepare chip. The array-based caspase-activity patterned chip (Casp-PC) is fabricated by hydrophobically assembling different phospholipid-tagged peptide substrates on a modified ITO slide. The advantages of amphipathic phospholipids lead to high-quality mass spectra for imaging analysis. Upon the respective cleavage of these substrates by different caspases, such as caspase-1, -2, -3, and -8, to produce a mass shift, the enzyme activities can be directly evaluated by MALDI-MS patterning by m/z-dependent imaging of the cleavage products. The ability to identify drug-sensitive/resistant cancer cells and assess the curative effects of anticancer drugs is demonstrated, indicating the applicability of the method and the designed chip.

The actin filament cross-linker L-plastin confers resistance to TNF-alpha in MCF-7 breast cancer cells in a phosphorylation-dependent manner

We used a tumour necrosis factor (TNF)-α resistant breast adenocarcinoma MCF-7 cell line to investigate the involvement of the actin cytoskeleton in the mechanism of cell resistance to this cytokine. We found that TNF resistance correlates with the loss of cell epithelial properties and the gain of a mesenchymal phenotype, reminiscent of an epithelial-to-mesenchymal transition (EMT). Morphological changes were associated with a profound reorganization of the actin cytoskeleton and with a change in the repertoire of expressed actin cytoskeleton genes and EMT markers, as revealed by DNA microarray-based expression profiling. L-plastin, an F-actin cross-linking and stabilizing protein, was identified as one of the most significantly up-regulated genes in TNF-resistant cells. Knockdown of L-plastin in these cells revealed its crucial role in conferring TNF resistance. Importantly, overexpression of wild-type L-plastin in TNF-sensitive MCF-7 cells was sufficient to protect them against TNF-mediated cell death. Furthermore, we found that this effect is dependent on serine-5 phosphorylation of L-plastin and that non-conventional protein kinase C isoforms and the ceramide pathway may regulate its phosphorylation state. The protective role of L-plastin was not restricted to TNF-α resistant MCF-7 cells because a correlation between the expression of L-plastin and the resistance to TNF-α was observed in other breast cancer cell lines. Together, our study discloses a novel unexpected role of the actin bundling protein L-plastin as a cell protective protein against TNF-cytotoxicity.

Ellagitannin (BJA3121), an anti-proliferative natural polyphenol compound, can regulate the expression of MiRNAs in HepG2 cancer cells

MicroRNAs (miRNAs) play an important role in cancers. A number of miRNA expression-profiling studies have been done to identify the miRNA signatures of cancers from different cellular origin. There is, however, relatively little information on how anticancer agents regulate miRNA expression. Ellagitannin (BJA3121), 1,3-Di-O-galloyl-4,6-(s)-HHDP-b-D-glucopyranose, is a new natural polyphenol compound isolated from Balanophora Japonica MAKINO. Our preliminary results have shown that BJA3121 had antiproliferative effect and modified the expression of different genes in human HepG(2) cancer cells. In this study, we further evaluate whether this antineoplastic compound is able to alter miRNA expression in HepG(2) cells. We demonstrated for the first time that BJA3121 can regulate the expression of 25 miRNAs, including 17 upregulated and 8 downregulated miRNAs in HepG(2) cells. Our results suggested that BJA3121-modifed miRNA expression can mediate, at least in part, the antiproliferative and multigene regulatory action induced by the compound on HepG(2) cancer cells.

Change in TNF-alpha receptor expression is a relevant event in doxorubicin-induced H9c2 cardiomyocyte cell death

Doxorubicin (Doxo) is a widely used anticancer drug given for the treatment of leukemias, lymphomas, and solid tumors. Despite its potent antitumor effects, the cardiotoxicity of this drug limits its clinical use. The biochemical mechanisms of Doxo-induced cardiotoxicity remain unclear. Doxo has been shown to induce apoptosis in cardiomyocytes that seems to be responsible, at least in part, for Doxo cardiotoxicity. In this study, we investigated tumor necrosis factor-alpha (TNF-alpha) receptor-mediated signaling to better understand the causes of Doxo-induced cardiotoxicity. Here, we report that Doxo is a potent inducer of apoptosis in both H9c2 cardiomyocytes and U2OS osteosarcoma tumor cells, with significant differences in terms of kinetics and caspase activation between the two cell lines. Interestingly, Doxo-induced apoptosis is accompanied by relevant changes in TNF-alpha receptor levels in H9c2 cardiomyocytes but not in U2OS cells. Moreover, treatment with exogenous TNF-alpha strongly potentiates the apoptotic effect of Doxo in H9c2 cardiomyocytes but not in U2OS cells. Our findings show that the function of TNF receptors I and II is affected by Doxo to ultimately modulate apoptosis and cell survival in H9c2 cardiomyocytes, reinforcing the recent evidence of the relevant role of TNF-alpha receptor-mediated signaling in cardiotoxicity induced by anthracyclines.

Mapping genes that contribute to daunorubicin-induced cytotoxicity

Daunorubicin is an anthracycline antibiotic agent used in the treatment of hematopoietic malignancies. Toxicities associated with this agent include myelosuppression and cardiotoxicity; however, the genes or genetic determinants that contribute to these toxicities are unknown. We present an unbiased genome-wide approach that incorporates heritability, whole-genome linkage analysis, and linkage-directed association to uncover genetic variants contributing to the sensitivity to daunorubicin-induced cytotoxicity. Cell growth inhibition in 324 Centre d' Etude du Polymorphisme Humain lymphoblastoid cell lines (24 pedigrees) was evaluated following treatment with daunorubicin for 72 h. Heritability analysis showed a significant genetic component contributing to the cytotoxic phenotypes (h2 = 0.18-0.63 at 0.0125, 0.025, 0.05, 0.1, 0.2, and 1.0 mumol/L daunorubicin and at the IC50, the dose required to inhibit 50% cell growth). Whole-genome linkage scans at all drug concentrations and IC50 uncovered 11 regions with moderate peak LOD scores (> 1.5), including 4q28.2 to 4q32.3 with a maximum LOD score of 3.18. The quantitative transmission disequilibrium tests were done using 31,312 high-frequency single-nucleotide polymorphisms (SNP) located in the 1 LOD confidence interval of these 11 regions. Thirty genes were identified as significantly associated with daunorubicin-induced cytotoxicity (P < or = 2.0 x 10(-4), false discovery rate < or = 0.1). Pathway and functional gene ontology analysis showed that these genes were overrepresented in the phosphatidylinositol signaling system, axon guidance pathway, and GPI-anchored proteins family. Our findings suggest that a proportion of susceptibility to daunorubicin-induced cytotoxicity may be controlled by genetic determinants and that analysis using linkage-directed association studies with dense SNP markers can be used to identify the genetic variants contributing to cytotoxicity.

Requirement for pre-existing of p21 to prevent doxorubicin-induced apoptosis through inhibition of caspase-3 activation

Doxorubicin (DOX)-induced apoptosis is suppressed by p21 (waf1/cip1/sdi1), a cyclin dependent kinase (CDK) inhibitor. Here we show that exogenous expression of p21 before, but not after, the DOX-treatment protected p21-deficient human colorectal cancer cell line DLD1 from DOX-induced apoptosis. In previous work, we demonstrated that p21 inhibits DOX-induced apoptosis via its CDK-binding and CDK-inhibitory activity. Here we report that pre-existing p21 can associate with pro-caspase-3 and inhibit caspase-3 activation in the cells, which was at least in part responsible for enhancing survival of DOX-treated cells. Furthermore, the N-terminal domain of p21 was found to interact with pro-caspase-3 in DLD1 cells. Thus, we propose that pre-existing p21 is required to prevent DOX-induced apoptosis.