Taxol Induces Caspase-10-dependent Apoptosis

Caspase-8 in inflammatory diseases: a potential therapeutic target

Caspase-8, a renowned cysteine-aspartic protease within its enzyme family, initially garnered attention for its regulatory role in extrinsic apoptosis. With advancing research, a growing body of evidence has substantiated its involvement in other cell death processes, such as pyroptosis and necroptosis, as well as its modulatory effects on inflammasomes and proinflammatory cytokines. PANoptosis, an emerging concept of cell death, encompasses pyroptosis, apoptosis, and necroptosis, providing insight into the often overlapping cellular mortality observed during disease progression. The activation or deficiency of caspase-8 enzymatic activity is closely linked to PANoptosis, positioning caspase-8 as a key regulator of cell survival or death across various physiological and pathological processes. Aberrant expression of caspase-8 is closely associated with the development and progression of a range of inflammatory diseases, including immune system disorders, neurodegenerative diseases (NDDs), sepsis, and cancer. This paper delves into the regulatory role and impact of caspase-8 in these conditions, aiming to elucidate potential therapeutic strategies for the future intervention.

Integrated stress response (ISR) activation and apoptosis through HRI kinase by PG3 and other p53 pathway-restoring cancer therapeutics

Restoration of the p53 pathway has been a long-term goal in the field of cancer research to treat tumors with mutated p53 and aggressive clinical behavior. p53 pathway restoration in p53-deficient cancers can be achieved by small molecules via p53-dependent or p53-independent processes. Hereafter p53-independent restoration of p53-pathway-signaling in p53-deficient/mutated tumors is referred to as 'restoration of the p53 pathway'. We compare activation of p53 target genes by novel compounds PG3 and PG3-Oc, that activate p53-target genes in a p53-independent manner, and four mutant p53-activating compounds while Nutlin-3a is used as negative control. PG3 and PG3-Oc upregulate p21, PUMA, and DR5 in five cancer cell lines with various p53 mutational statuses through ATF4 (Activating Transcriptional Factor 4) and integrated stress response (ISR) independent of p53. Mutant p53-targeting compounds induce expression of the 3 major downstream p53 target genes and ATF4 in a highly variable and cell-type-dependent manner. PG3 treatment activates ATF4 through ISR via kinase HRI (Heme-Regulated Inhibitor). ATF4 mediates upregulation of PUMA, p21, and NAG-1/GDF15 (Nonsteroidal anti-inflammatory drug-activated gene 1). We note that PUMA mediates apoptosis through activation of caspase-8 in HT29 cells and potentially caspase-10 in SW480 cells. We provide a novel mechanism engaged by PG3 to induce cell death via the HRI/ATF4/PUMA axis. Our results provide unique insights into the mechanism of action of PG3 as a novel cancer therapeutic targeting p53 pathway-like tumor suppression.

Chemical synthetic approaches to mimic the TRAIL: promising cancer therapeutics

Apoptosis is programmed cell death that eliminates undesired cells to maintain homeostasis in metazoan. Aberration of this process may lead to cancer genesis. The tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces apoptosis in cancer cells after ligation with death receptors (DR4/DR5) while sparing most normal cells. Therefore, strategies to induce apoptosis in cancer cells by mimicking the TRAIL emerge as a promising therapeutic tool. Hence, approaches are taken to develop TRAIL/DR-based cancer therapeutics. The recombinant soluble TRAIL (rhTRAIL) and death receptor agonistic antibodies were produced and tested pre-clinically and clinically. Pre-clinical and clinical trial data demonstrate that these therapeutics are safe and relatively well tolerated. But some of these therapeutics failed to exert adequate efficacy in clinical settings. Besides these biotechnologically derived therapeutics, a few chemically synthesized therapeutics are reported. Some of these therapeutics exert considerable efficacy in vitro and in vivo. In this review, we will discuss chemically synthesized TRAIL/DR-based therapeutics, their chemical and biological behaviour, design concepts and strategies that may contribute to further improvement of TRAIL/DR-based therapeutics.

Androgen receptor-mediated pharmacogenomic expression quantitative trait loci: implications for breast cancer response to AR-targeting therapy

BACKGROUND

Endocrine therapy is the most important treatment modality of breast cancer patients whose tumors express the estrogen receptor α (ERα). The androgen receptor (AR) is also expressed in the vast majority (80-90%) of ERα-positive tumors. AR-targeting drugs are not used in clinical practice, but have been evaluated in multiple trials and preclinical studies.

METHODS

We performed a genome-wide study to identify hormone/drug-induced single nucleotide polymorphism (SNP) genotype - dependent gene-expression, known as PGx-eQTL, mediated by either an AR agonist (dihydrotestosterone) or a partial antagonist (enzalutamide), utilizing a previously well characterized lymphoblastic cell line panel. The association of the identified SNPs-gene pairs with breast cancer phenotypes were then examined using three genome-wide association (GWAS) studies that we have published and other studies from the GWAS catalog.

RESULTS

We identified 13 DHT-mediated PGx-eQTL loci and 23 Enz-mediated PGx-eQTL loci that were associated with breast cancer outcomes post ER antagonist or aromatase inhibitors (AI) treatment, or with pharmacodynamic (PD) effects of AIs. An additional 30 loci were found to be associated with cancer risk and sex-hormone binding globulin levels. The top loci involved the genes IDH2 and TMEM9, the expression of which were suppressed by DHT in a PGx-eQTL SNP genotype-dependent manner. Both of these genes were overexpressed in breast cancer and were associated with a poorer prognosis. Therefore, suppression of these genes by AR agonists may benefit patients with minor allele genotypes for these SNPs.

CONCLUSIONS

We identified AR-related PGx-eQTL SNP-gene pairs that were associated with risks, outcomes and PD effects of endocrine therapy that may provide potential biomarkers for individualized treatment of breast cancer.

A Focused Review of the Pharmacological Potentials of Terrein as an Anticancer Agent

Terrein is one of the most important biomolecules of fungal origin being studied from a medicinal perspective. Secondary metabolites are the intermediate products produced during the metabolism of organisms for a large number of functions, for example, defense and communication signals. From the outset, terrein has largely been studied as an anticancer secondary biomolecule. Aspergillus terreus is the only fungal source of some valuable drugs and mycotoxins. From the beginning, a few species of Aspergillus were known to be viable chemical factories. Terrein is a potent biological molecule present in the fungus that is responsible for its medicinal and agricultural values. Numerous evaluations conducted on terrein showed it to have marked biological activities (antimicrobial, antiproliferative, anti-oxidative, and others). To date, terrein has emerged as a very attractive therapeutic regimen against cancer due to its dual targeting nature; tumor angiogenesis and cell proliferation. This focused review provides details of the therapeutic value of terrein and its modes of action as an anticancer agent. Besides this, terrein has other marked bioactivities and manifold uses in the field of medicine, which have also been discussed here.

Immunomodulatory role of estrogen in ischemic stroke: neuroinflammation and effect of sex

Although estrogen is predominantly related to the maintenance of reproductive functioning in females, it mediates various physiological effects in nearly all tissues, especially the central nervous system. Clinical trials have revealed that estrogen, especially 17β-estradiol, can attenuate cerebral damage caused by an ischemic stroke. One mechanism underlying this effect of 17β-estradiol is by modulating the responses of immune cells, indicating its utility as a novel therapeutic strategy for ischemic stroke. The present review summarizes the effect of sex on ischemic stroke progression, the role of estrogen as an immunomodulator in immune reactions, and the potential clinical value of estrogen replacement therapy. The data presented here will help better understand the immunomodulatory function of estrogen and may provide a basis for its novel therapeutic use in ischemic stroke.

Prostate Cancer and microRNAs: New insights into Apoptosis

Prostate cancer (PCa) is known as one of the most prevalent malignancies globally and is not yet curable owing to its progressive nature. It has been well documented that Genetic and epigenetic alterations maintain mandatory roles in PCa development. Apoptosis, a form of programmed cell death, has been shown to be involved in a number of physiological processes. Apoptosis disruption is considered as one of the main mechanism involved in lots of pathological conditions, especially malignancy. There is ample of evidence in support of the fact that microRNAs (miRNAs) have crucial roles in several cellular biological processes, including apoptosis. Escaping from apoptosis is a common event in malignancy progression. Emerging evidence revealed miRNAs capabilities to act as apoptotic or anti-apoptotic factors by altering the expression levels of tumor inhibitor or oncogene genes. In the present narrative review, we described in detail how apoptosis dysfunction could be involved in PCa processes and additionally, the mechanisms behind miRNAs affect the apoptosis pathways in PCa. Identifying the mechanisms behind the effects of miRNAs and their targets on apoptosis can provide scientists new targets for PCa treatment.

Recent Advances in Isolation, Synthesis and Biological Evaluation of Terrein

Terrein is a small-molecule polyketide compound with a simple structure mainly isolated from fungi. Since its discovery in 1935, many scholars have conducted a series of research on its structure identification, isolation source, production increase, synthesis and biological activity. Studies have shown that terrein has a variety of biological activities, not only can inhibit melanin production and epidermal hyperplasia, but also has anti-cancer, anti-inflammatory, anti-angiopoietic secretion, antibacterial, insecticidal activities, and so on. It has potential application prospects in beauty, medicine, agriculture and other fields. This article reviews the process of structural identification of terrein since 1935, and summarizes the latest advances in its isolation, source, production increase, synthesis, and biological activity evaluation, with a view to providing a reference and helping for the in-depth research of terrein.

Synergistic Antiproliferative Effects of All-Trans Retinoic Acid and Paclitaxel on Autosomal Dominant Polycystic Kidney Disease Epithelial Cells

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by uncontrollable epithelial cell growth, cyst formation, and kidney malfunction. In the present study, we investigated the antiproliferative effects of the treatment with the combination of paclitaxel (PAC) and all-trans retinoic acid (ATRA) on ADPKD epithelial cells. Our results show that the combined treatment with 1 nM PAC and 10 nM ATRA significantly suppressed ADPKD cell proliferation (20%), while the treatment with ATRA or PAC alone had no such effect. Treatment with PAC and ATRA induced cell cycle arrest at the G2/M phase and apoptosis by upregulating p53 and caspase-8 expression and increased the intracellular calcium (Ca²⁺) level possibly by enhancing Ca²⁺ uptake via plasma membrane channels. In addition, this treatment suppressed extracellular signal-regulated kinase signaling possibly through mitogen-activated protein kinase phosphatase-1 activation. Thus, the combination of PAC and ATRA can be explored as a potential treatment regimen for ADPKD.

Role of JNK activation in paclitaxel-induced apoptosis in human head and neck squamous cell carcinoma

It has been reported that paclitaxel activates cell cycle arrest and increases caspase protein expression to induce apoptosis in head and neck squamous cell carcinoma (HNSCC) cell lines. However, the potential signaling pathway regulating this apoptotic phenomenon remains unclear. The present study used OEC-M1 cells to investigate the underlying molecular mechanism of paclitaxel-induced apoptosis. Following treatment with paclitaxel, cell viability was assessed via the MTT assay. Necrosis, apoptosis, cell cycle and mitochondrial membrane potential (∆Ψm) were analyzed via flow cytometric analyses, respectively. Western blot analysis was performed to detect the expression levels of proteins associated with the MAPK and caspase signaling pathways. The results demonstrated that low-dose paclitaxel (50 nM) induced apoptosis but not necrosis in HNSCC cells. In addition, paclitaxel activated the c-Jun N-terminal kinase (JNK), but not extracellular signal-regulated kinase or p38 mitogen-activated protein kinase. The paclitaxel-activated JNK contributed to paclitaxel-induced apoptosis, activation of caspase-3, -6, -7, -8 and -9, and reduction of ∆Ψm. In addition, caspase-8 and -9 inhibitors, respectively, significantly decreased paclitaxel-induced apoptosis. Notably, Bid was truncated following treatment with paclitaxel. Taken together, the results of the present study suggest that paclitaxel-activated JNK is required for caspase activation and loss of ∆Ψm, which results in apoptosis of HNSCC cells. These results may provide mechanistic basis for designing more effective paclitaxel-combining regimens to treat HNSCC.

Targeted nanoformulation of C1 inhibits the growth of KB spheroids and cancer stem cell-enriched MCF-7 mammospheres

C1, a synthetic analog of curcumin, has been reported to show potent antiproliferative effects against a variety of cancer cells. Here, we report a strong anticancer activity of the folate receptor-targeted lipid nanoparticle formulation of C1 against cancer cells and cancer stem cells both in 2D culture and 3D spheroids. The size of the C1 encapsulated folic acid functionalized nanoliposomes (Lipos-C1) was determined to be 83 ± 17 nm. Lipos-C1 nanoparticles displayed sustained C1 release kinetics at both pH 7.4 and 5.5. The folate receptor (FR) targeted nanoliposomes were internalized into FR-positive KB cells via the folate receptor-mediated endocytosis process. Lipos-C1 killed KB cells much more efficiently than C1. Lipos-C1 depolymerized microtubules, generated ROS, caused DNA damage, and induced apoptosis in KB cells. Importantly, Lipos-C1 strongly inhibited the growth of the 3D KB spheroids than C1. Interestingly, Lipos-C1 also suppressed cancer stem cells (CSCs) enriched MCF-7 mammosphere growth by impeding breast cancer stem cells (BCSCs) enrichment, growth, and proliferation. The results suggested that Lipos-C1 could be a promising nanoformulation for cancer chemotherapy.

Loss of FADD and Caspases Affects the Response of T-Cell Leukemia Jurkat Cells to Anti-Cancer Drugs

Programmed cell death (PCD) pathways play a crucial role in the response of cancer cells to treatment. Their dysregulation is one of the cancer hallmarks and one of the reasons of drug resistance. Here, we studied the significance of the individual members of PCD signaling pathways in response to treatment with common anti-cancer drugs using the T-cell leukemia Jurkat cells with single or double knockouts of necroptosis and/or apoptosis genes. We identified apoptosis as the primary cell death pathway upon anti-cancer drugs treatment. The cells with knocked out either Fas-associated protein with death domain (FADD) or all executioner caspases were resistant. This resistance could be partially overcome by induction of RIP1-dependent necroptosis through TNFR1 activation using combined treatment with TNF-α and smac mimetic (LCL161). RIP1 was essential for cellular response to TNF-α and smac mimetic, but dispensable for the response to anti-cancer drugs. Here, we demonstrated the significance of FADD and executioner caspases in carrying out programmed cell death upon anti-cancer drug treatments and the ability of combined treatment with TNF-α and smac mimetic to partially overcome drug resistance of FADD and/or CASP3/7/6-deficient cells via RIP1-dependent necroptosis. Thus, a combination of TNF-α and smac mimetic could be a suitable strategy for overcoming resistance to therapy in cells unable to trigger apoptosis.

Sub-acute Toxicity Assessment of Taxol Isolated From Fusarium Solani, an Endophytic Fungus of Taxus Brevifolia, in Wistar Rats and Analyzing Its Cytotoxicity and Apoptotic Potential in Lung Cancer Cells

The limited availability of taxol from plant sources has prompted the scientific world to look for an alternative, as in the chemical synthesis of tissue cultures of the Taxus species, to meet the increasing demand for the drug. However, these alternative means are expensive or result in low yield. Previously, we have reported that Fusarium solani isolated from Taxus celebica produced taxol and its precursor baccatin III in liquid-grown cultures, and it exhibited promising anticancerous effects in certain cancer cell lines. In the present study, we examined the sub-acute toxicity of fungal taxol (FS) in Wistar rats according to the Organization for Economic Co-operation and Development (OECD) guidelines. The sub-acute oral administration of FS up to 500 mg/kg for a period of 28 days appears to be safe in rats and did not cause severe treatment-related toxicity or treatment-related death. The observed changes in body weight, histopathology, hematological and biochemical parameters, and organ weight were not significant compared to those in the control group of animals. The results suggest that FS is relatively safe when administered orally in rats. The antiproliferative and apoptosis-inducing activities were studied in A549 (human lung cancer) cell line. FS arrested the cells at S and G2/M phases, leading to apoptosis. The characteristic molecular signatures of apoptosis, such as externalized phosphatidyl serine, DNA fragmentation, and nuclear and chromatin condensation, were observed upon FS treatment. FS triggered the generation of reactive oxygen species in A549 cells and elicited cell death by both extrinsic as well as the mitochondria-mediated intrinsic pathway of apoptosis. These results indicate that endophytic fungi isolated from medicinal plants may serve as potential sources of anticancerous compounds with little side effects.

Long noncoding RNA PVT1 facilitates high glucose-induced cardiomyocyte death through the miR-23a-3p/CASP10 axis

Dilated cardiomyopathy (DCM) is the leading cause of morbidity and mortality in diabetic patients. Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) has been shown to be related to the pathogenesis of DCM. However, the mechanism by which PVT1 regulates DCM pathogenesis is unclear. High glucose level was employed to construct a DCM cell model in vitro. Cell viability was determined via cell counting kit-8 assay. The level of lactate dehydrogenase (LDH) was measured with the corresponding kit. Expression levels of PVT1, miR-23a-3p, and caspase-10 (CASP10) messenger RNA were evaluated with a quantitative real-time polymerase chain reaction. Cell apoptosis was assessed by flow cytometry assay. Protein levels of B-cell lymphoma 2-associated X (Bax), cleaved-caspase-3 (cleaved-casp-3), and CASP10 were examined via western blot analysis. The relationship between PVT1 or CASP10 and miR-23a-3p was verified with dual-luciferase reporter assay. We observed that PVT1 and CASP10 were upregulated while miR-23a-3p was downregulated in high glucose-induced cardiomyocytes. High glucose levels repressed cardiomyocyte activity and induced cardiomyocyte apoptosis, but this influence was antagonized by PVT1 knockdown or miR-23a-3p overexpression. Furthermore, PVT1 acted as a sponge for miR-23a-3p, and miR-23a-3p inhibition counterbalanced the influence of PVT1 silencing on viability and apoptosis of cardiomyocytes under high glucose level treatment. PVT1 could increase CASP10 expression via sponging miR-23a-3p. In conclusion, PVT1 acted as a deleterious lncRNA in DCM. PVT1 facilitated cardiomyocyte death by regulating the miR-23a-3p/CASP10, which offered a new mechanism to comprehend the pathogenesis of DCM.

Single-Cell Multimodal Analytical Approach by Integrating Raman Optical Tweezers and RNA Sequencing

Single-cell analysis has become a state-of-art approach to heterogeneity profiling in tumor cells. Herein, we realize a kind of single-cell multimodal analytical approach by combining single-cell RNA sequencing (scRNA-seq) with Raman optical tweezers (ROT), a label-free single-cell identification and isolation technique, and apply it to investigate drug sensitivity. The drug sensitivity of human BGC823 gastric cancer cells toward different drugs, paclitaxel and sodium dichloroacetate, was distinguished in the conjoint analytical way including morphology monitoring, Raman identification, and transcriptomic profiling. Each individual BGC823 cancer cell was measured by Raman spectroscopy, then nondestructively isolated out by ROT, and finally RNA-sequenced. Our results demonstrate each analytical mode can reflect cell response to the drugs from different perspectives and is consistent and complementary with each other. Therefore, we believe the multimodal analytical approach offers an access to comprehensive characterizations of the unicellular complexity, which especially makes sense for studying tumor heterogeneity or a desired special cell from a mixture cell sample such as whole blood.

A one-step molded microfluidic chip featuring a two-layer silver-PDMS microelectrode for dielectrophoretic cell separation

Dielectrophoresis (DEP) is a powerful technique for label-free cell separation in microfluidics. Easily-fabricated DEP separators with low cost and short turnaround time are in extremely high demand in practical applications, especially clinical usage where disposable devices are needed. DEP separators exploiting microelectrodes made of conducting polydimethylsiloxane (PDMS) composites enable the construction of advantageous 3D volumetric electrodes with a simple soft-lithography process. Yet, existing devices incorporating microelectrodes in conducting PDMS generally have their fluidic sidewalls constructed using a different material, and consequently require extra lithography of a sacrificial layer on the semi-finished master for molding the electrode and fluidic sidewalls in separate steps. Here we demonstrate a novel microfluidic DEP separator with a 3D electrode and fluidic structure entirely integrated within silver-PDMS composites. We develop a further simplified one-step molding process with lower cost using a readily-available and reusable SU8 master, eliminating the need for the additional lithography step in existing techniques. The uniquely designed two-layer electrode exhibits a spatially non-uniform electric field that enables cell migration in the vertical direction. The electrode upper layer then offers a harbor-like region for the trapping of the target cells that have drifted upwards, which shelters them from being dragged away by the main flow streams in the lower layer, and thus allows higher operation flow rate. We also optimize the upper layer thickness as a critical dimension for protecting the trapped cells from high drag and show easy widening of our device by elongation of the digits. We demonstrate that the elongated digits involving more parallel flow paths maintain a high capture efficiency of 95.4% for live cells with 85.6% purity in the separation of live/dead HeLa cells. We also investigate the device feasibility in a viability assay for cells post anti-cancer drug treatment.

Alternative sources and metabolic engineering of Taxol: Advances and future perspectives

Paclitaxel is one of the strong plant-derived anti-cancer drugs that was first isolated from the Pacific yew. Despite many paclitaxel's clinical successes, the limited accessibility of paclitaxel for clinical trials is recognized as the most important challenge. Thus, researchers are continuously trying to find the innovative ways to meet the community's need for this medicine. In the first step, the alternative sources for Taxol supply were recognized, such as Taxus genus, other plant genera, and endophytic fungi. In the next step, the biosynthetic pathways of Taxol or related metabolites were manipulated in the original organisms, or introduced to heterologous systems and then were manipulated in them. Here, a range of metabolic manipulating approaches have been successfully developed to redirect the metabolic flux toward Taxol, including promoter engineering, enzyme engineering, overexpressing the bottleneck enzymes, over- or down-regulation of transcription factors, activation of the cryptic genes, removing/minimizing the flux for competing pathways, tunable regulation of the metabolic pathway, and increasing the supplies of precursors. In this review, we discuss research progress on the alternative Taxol sources and its metabolic manipulating, and we suggest recent challenges and future perspectives.

Detoxification, Apoptosis, and Immune Transcriptomic Responses of the Gill Tissue of Bay Scallop Following Exposure to the Algicide Thiazolidinedione 49

Thiazolidinedione 49 (TD₄₉), a newly synthesized algicide, shows strong toxicity at low concentrations of 0.1-2.0 μM. However, its potential effects on non-target species at the transcript level were not investigated. Differentially expressed genes (DEGs) in the gills of the bay scallop, Argopecten irradians, were accessed after treatment with 0.68 μM TD₄₉ for up to 48 h. Following exposure, it was observed that 5214 genes were upregulated and 3497 were downregulated. Functional enrichment analysis revealed that the apoptosis pathway was activated. The extrinsic apoptosis pathway was activated and the survival factors related pathway was suppressed. Furthermore, gene expressions related to ATP-binding cassette, nuclear factor erythroid 2-related factor, B cell lymphoma-2 family protein, glutathione reductase, glutathione peroxidase, catalase, NADPH2:quinone reductase, and superoxide dismutase were decreased. Conversely, gene expressions related to FAS-associated death domain protein, glutathione S-transferase, caspase 6, 8, cytochrome P450 1A1, and 2C8 were increased. These results comprehensively demonstrated the toxicity of the novel algicide TD₄₉, and should draw the attention of researchers to the importance of analyzing the potential impact of chemical compounds as algicides to control the proliferation of harmful algae, due to the secondary pollution caused by their application.

Intracellular catalase activity instead of glutathione level dominates the resistance of cells to reactive oxygen species

Artesunate (ARS) induced significant reactive oxygen species (ROS) generation in HepG2, HeLa, and A549 lines. However, ARS induced ROS-dependent apoptosis in HeLa and A549 cell lines but ROS-independent apoptosis in HepG2 cells. A total of 200 μM hydrogen peroxide (H2O2) significantly induced cytotoxicity in HeLa cells, while H2O2 up to 300 μM did not induce cytotoxicity in HepG2 cells, further demonstrating the strong resistance of HepG2 cells to ROS. HeLa cells had much higher basic total glutathione (T-GSH) level than HepG2 cells, while the ratio of basic reduced glutathione (GSH)/oxidized glutathione (GSSG) in HepG2 cells was nearly twice than that in HeLa and A549 cells. Inhibition of glutathione markedly enhanced H2O2- or ARS-induced cytotoxicity in HeLa and A549 cell lines but modestly enhanced the cytotoxicity of H2O2 and even did not affect the cytotoxicity of ARS in HepG2 cells. Moreover, addition of GSH remarkably prevented H2O2- or ARS-induced cytotoxicity in HeLa and A549 cell lines, further indicating the involvement of GSH in scavenging ROS in the two cell lines. HepG2 cells exhibited higher catalase activity than HeLa cells, and inhibiting catalase activity by using 3-aminotriazole (3-AT, a specific inhibition of catalase) or catalase siRNA remarkably reduced the resistance of HepG2 cells to ROS, demonstrating the key roles of catalase for the strong resistance of HepG2 cells to ROS. Collectively, catalase activity instead of glutathione level dominates the resistance of cells to ROS.

May a sigma-1 antagonist improve neuropathic signs induced by cisplatin and vincristine in rats?

BACKGROUND

The antineoplastic drugs cisplatin and vincristine induce peripheral neuropathies. The sigma-1 receptor (σ1R) is expressed in areas of pain control, and its blockade with the novel selective antagonist MR-309 has shown efficacy in nociceptive and neuropathic pain models. Our goal was to test whether this compound reduces neuropathic signs provoked by these antitumoural drugs.

METHODS

Rats were treated with cisplatin or vincristine to induce neuropathies. The effects of acute or repeated administration of MR-309 were tested on mechanical and thermal sensitivity, electrophysiological activity of Aδ-primary afferents in the rat skin-saphenous nerve preparation, and gastrointestinal or cardiovascular functions.

RESULTS

Rats treated with antitumourals developed tactile allodynia, while those treated with vincristine also developed mechanical hyperalgesia. These in vivo modifications correlated with electrophysiological hyperactivity (increased spontaneous activity and hyperresponsiveness to innocuous and noxious mechanical stimulation). Animals treated with cisplatin showed gastrointestinal impairment and those receiving vincristine showed cardiovascular toxicity. A single dose of MR-309 strongly reduced both nociceptive behaviour and electrophysiological changes. Moreover, its concomitant administration with the antitumourals blocked the development of neuropathic symptoms, thus restoring mechanical sensitivity, improving the impairment of feeding behaviour and gastrointestinal transit in the cisplatin-treated group along with ameliorating the altered vascular reactivity recorded in rats treated with vincristine.

CONCLUSION

σ1R antagonist, MR-309, reduces sensorial and electrophysiological neuropathic signs in rats treated with cisplatin or vincristine and, in addition, reduces gastrointestinal and cardiovascular side effects.

SIGNIFICANCE

σ1R antagonism could be an interesting and new option to palliate antitumoural neuropathies.

An updated understanding of the mechanisms involved in chemotherapy-induced neuropathy

The burdensome condition of chemotherapy-induced peripheral neuropathy occurs with various chemotherapeutics, including bortezomib, oxaliplatin, paclitaxel and vincristine. The symptoms, which include pain, numbness, tingling and loss of motor function, can result in therapy titrations that compromise therapy efficacy. Understanding the mechanisms of chemotherapy-induced peripheral neuropathy is therefore essential, yet incompletely understood. The literature presented here will address a multitude of molecular and cellular mechanisms, beginning with the most well-understood cellular and molecular-level changes. These modifications include alterations in voltage-gated ion channels, neurochemical transmission, organelle function and intracellular pathways. System-level alterations, including changes to glial cells and cytokine activation are also explored. Finally, we present research on the current understanding of genetic contributions to this condition. Suggestions for future research are provided.

Wen-Luo-Tong Decoction Attenuates Paclitaxel-Induced Peripheral Neuropathy by Regulating Linoleic Acid and Glycerophospholipid Metabolism Pathways

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious dose-limiting toxicity of many anti-neoplastic agents, especially paclitaxel, and oxaliplatin. Up to 62% of patients receiving paclitaxel regimens turn out to develop CIPN. Unfortunately, there are so few agents proved effective for prevention or management of CIPN. The reason for the current situation is that the mechanisms of CIPN are still not explicit. Traditional Chinese Medicine (TCM) has unique advantages for dealing with complex diseases. Wen-Luo-Tong (WLT) is a TCM ointment for topical application. It has been applied for prevention and management of CIPN clinically for more than 10 years. Previous animal experiments and clinical studies had manifested the availability of WLT. However, due to the unclear mechanisms of WLT, further transformation has been restricted. To investigate the therapeutic mechanisms of WLT, a metabolomic method on the basis of UPLC- MS was developed in this study. Multivariate analysis techniques, such as principal component analysis (PCA) and partial least squares discriminate analysis (PLS-DA), were applied to observe the disturbance in the metabolic state of the paclitaxel-induced peripheral neuropathy (PIPN) rat model, as well as the recovering tendency of WLT treatment. A total of 19 significant variations associated with PIPN were identified as biomarkers. Results of pathway analysis indicated that the metabolic disturbance of pathways of linoleic acid (LA) metabolism and glycerophospholipid metabolism. WLT attenuated mechanical allodynia and rebalanced the metabolic disturbances of PIPN by primarily regulating LA and glycerophospholipid metabolism pathway. Further molecular docking analysis showed some ingredients of WLT, such as hydroxysafflor yellow A (HSYA), icariin, epimedin B and 4-dihydroxybenzoic acid (DHBA), had high affinity to plenty of proteins within these two pathways.

Cytotoxic effect of Kalanchoe flammea and induction of intrinsic mitochondrial apoptotic signaling in prostate cancer cells

ETHNOPHARMACOLOGICAL IMPORTANCE

Kalanchoe flammea Stapf (Crassulaceae) is a medicinal plant grown in the South of Mexico (State of Tabasco), which is commonly used in traditional medicine for the treatment of fever, wounds, inflammation, and cancer.

AIM OF THE STUDY

To establish the potential of K. flammea for the treatment of prostate cancer, evaluating its cytotoxic activity, its probable mechanism of action, and carrying out some toxicological safety studies.

MATERIALS AND METHODS

The cytotoxic activity of the ethyl acetate extract of K. flammea (Kf-EtOAc) was evaluated in several cell lines of prostate cancer by MTT viability assay. The cellular death mechanism was studied by evaluating the translocation of phosphatidylserine (Annexin V); overproduction of reactive oxygen species [2'-7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) assay]; release of Cytochrome C; activation of caspase-3 and -9, and regulation of Bcl-2, XIAP, and PKCε proteins by Western Blot analysis. For the evaluation of the safety of Kf-EtOAc, the Ames test, Micronucleus assay, and acute toxicity study were determined.

RESULTS

Kf-EtOAc exhibited selective cytotoxic activity against prostate cell lines as follows: PC-3, LNCaP, and PrEC (IC₅₀ = 1.36 ± 0.05; 2.06 ± 0.02, and 127.05 ± 0.07 μg/mL, respectively). The F82-P2 fraction (rich in coumaric acid and palmitic acid) obtained by bioassay-guided fractionation of Kf-EtOAc also demonstrated selective cytotoxic activity against PC-3 cells (IC₅₀ = 1.05 ± 0.06 μg/mL). Kf-EtOAc induces apoptosis by the intrinsic pathway; this mechanism of cell death was confirmed after observing that the extract produces phosphatidylserine translocation, overproduction of reactive oxygen species, release of Cytochrome C at mitochondrial level, and activation of caspase-3 and -9. It was also observed that Kf-EtOAc produces significant downregulation of apoptosis-related proteins Bcl-2, XIAP, and PKCε and induces DNA fragmentation and cell cycle arrest. In addition, Kf-EtOAc is non-genotoxic in vitro by Ames test and non-genotoxic in vivo by Micronucleus assay, and no signs of toxicity or death were reported after the administration of a single acute exposure of 2000 mg/kg.

CONCLUSION

K. flammea is a potential candidate for the development of new drugs for the treatment of prostate cancer. However, to propose their use in clinical trials, additional studies are required to understand their pharmacokinetic behavior, as well as the development of a suitable pharmaceutical form.

Therapeutic potential of patupilone in epithelial ovarian cancer and future directions

Ovarian cancer is the most lethal gynecologic malignancy worldwide with extremely poor patient prognosis. Elucidation of the detailed mechanisms of action of drugs targeting this cancer type is necessary to optimize treatment efficacy. Epothilones, a new class of microtubule-stabilizing anticancer drugs, show strong cytotoxic properties in vitro and in vivo and are additionally effective in taxane-resistant cells. In this report, we focus on inhibitors of microtubule depolymerization, taxanes, and the novel antimicrotubule agents, epothilones. Current knowledge regarding the effects of epothilone B on ovarian tumor cell metabolism is reviewed, along with recent advances in therapeutic strategies, such as novel agents and biologic drug combinations containing epothilone that target aberrant pathways in ovarian cancer.

Low doses of Paclitaxel repress breast cancer invasion through DJ-1/KLF17 signalling pathway

Paclitaxel (taxol) is an important agent against many tumours, including breast cancer. Ample data documents that paclitaxel inhibits breast cancer metastasis while others prove that paclitaxel enhances breast cancer metastasis. The mechanisms by which paclitaxel exerts its action are not well established. This study focuses on the effect of paclitaxel, particularly the low doses on breast cancer metastasis and the mechanisms that regulate it. Current results show that, paclitaxel exerts significant cytotoxicity even at low doses in both MCF-7 and MDA-MB-231 cells. Interestingly, paclitaxel significantly inhibits cell invasion and migration, decreases Snail and increases E-cadherin mRNA expression levels at the indicated low doses. Furthermore, paclitaxel-inhibiting breast cancer metastasis is associated with down-regulation of DJ-1 and ID-1 mRNA expression level with a concurrent increase in KLF17 expression. Under the same experimental conditions, paclitaxel induces KLF17 and concurrently represses ID-1 protein levels. Our results show for the first time that paclitaxel inhibits breast cancer metastasis through regulating DJ-1/KLF17/ID-1 signalling pathway; repressed DJ-1 and ID-1 and enhanced KLF17 expression.

A review on the effects of current chemotherapy drugs and natural agents in treating non-small cell lung cancer

Lung cancer is the leading cause of cancer deaths worldwide, and this makes it an attractive disease to review and possibly improve therapeutic treatment options. Surgery, radiation, chemotherapy, targeted treatments, and immunotherapy separate or in combination are commonly used to treat lung cancer. However, these treatment types may cause different side effects, and chemotherapy-based regimens appear to have reached a therapeutic plateau. Hence, effective, better-tolerated treatments are needed to address and hopefully overcome this conundrum. Recent advances have enabled biologists to better investigate the potential use of natural compounds for the treatment or control of various cancerous diseases. For the past 30 years, natural compounds have been the pillar of chemotherapy. However, only a few compounds have been tested in cancerous patients and only partial evidence is available regarding their clinical effectiveness. Herein, we review the research on using current chemotherapy drugs and natural compounds (Wortmannin and Roscovitine, Cordyceps militaris, Resveratrol, OSU03013, Myricetin, Berberine, Antroquinonol) and the beneficial effects they have on various types of cancers including non-small cell lung cancer. Based on this literature review, we propose the use of these compounds along with chemotherapy drugs in patients with advanced and/or refractory solid tumours.

Cell death response to anti-mitotic drug treatment in cell culture, mouse tumor model and the clinic

Anti-mitotic cancer drugs include classic microtubule-targeting drugs, such as taxanes and vinca alkaloids, and the newer spindle-targeting drugs, such as inhibitors of the motor protein; Kinesin-5 (aka KSP, Eg5, KIF11); and Aurora-A, Aurora-B and Polo-like kinases. Microtubule-targeting drugs are among the first line of chemotherapies for a wide spectrum of cancers, but patient responses vary greatly. We still lack understanding of how these drugs achieve a favorable therapeutic index, and why individual patient responses vary. Spindle-targeting drugs have so far shown disappointing results in the clinic, but it is possible that certain patients could benefit if we understand their mechanism of action better. Pre-clinical data from both cell culture and mouse tumor models showed that the cell death response is the most variable point of the drug action. Hence, in this review we focus on current mechanistic understanding of the cell death response to anti-mitotics. We first draw on extensive results from cell culture studies, and then cross-examine them with the more limited data from animal tumor models and the clinic. We end by discussing how cell type variation in cell death response might be harnessed to improve anti-mitotic chemotherapy by better patient stratification, new drug combinations and identification of novel targets for drug development.

The IL-6/STAT3 Signaling Pathway Is an Early Target of Manuka Honey-Induced Suppression of Human Breast Cancer Cells

There is renewed interest in the potential use of natural compounds in cancer therapy. Previously, we demonstrated the anti-tumor properties of manuka honey (MH) against several cancers. However, the underlying mechanism and molecular targets of this activity remain unknown. For this study, the early targets of MH and its modulatory effects on proliferation, invasiveness, and angiogenic potential were investigated using two human breast cancer cell lines, the triple-negative MDA-MB-231 cells and estrogen receptor-positive MCF-7 cells, and the non-neoplastic breast epithelial MCF-10A cell line. Exposure to MH at concentrations of 0.3-1.25% (w/v) induced a dose-dependent inhibition of the proliferation of MDA-MB-231 and MCF-7, but not MCF-10A, cells. This inhibition was independent of the sugar content of MH as a solution containing equivalent concentrations of its three major sugars failed to inhibit cell proliferation. At higher concentrations (>2.5%), MH was found to be generally deleterious to the growth of all three cell lines. MH induced apoptosis of MDA-MB-231 cells through activation of caspases 8, 9, 6, and 3/7 and this correlated with a loss of Bcl-2 and increased Bax protein expression in MH-treated cells. Incubation with MH induced a time-dependent translocation of cytochrome c from mitochondria to the cytosol and Bax translocation from the cytosol into the mitochondria. MH also induced apoptosis of MCF-7 cells via the activation of caspases 9 and 6. Low concentrations of MH (0.03-1.25% w/v) induced a rapid reduction in tyrosine-phosphorylated STAT3 (pY-STAT3) in MDA-MB-231 and MCF-7 cells. Maximum inhibition of pY-STAT3 was observed at 1 h with a loss of >80% and coincided with decreased interleukin-6 (IL-6) production. Moreover, MH inhibited the migration and invasion of MDA-MB-231 cells as well as the angiogenic capacity of human umbilical vein endothelial cells. Our findings identify multiple functional pathways affected by MH in human breast cancer and highlight the IL-6/STAT3 signaling pathway as one of the earliest potential targets in this process.

Synergistic Antitumour Properties of viscumTT in Alveolar Rhabdomyosarcoma

Aqueous mistletoe extracts from the European mistletoe (Viscum album) contain mainly mistletoe lectins and viscotoxins as cytotoxic compounds. Lipophilic triterpene acids, which do not occur in conventional mistletoe preparations, were solubilised with β-cyclodextrins. The combination of an aqueous extract (viscum) and a triterpene-containing extract (TT) recreated a whole mistletoe extract (viscumTT). These extracts were tested on rhabdomyosarcoma in vitro, ex vivo, and in vivo with regard to anticancer effects. Viscum and viscumTT inhibited cell proliferation and induced apoptosis effectively in a dose-dependent manner in vitro and ex vivo, whereas TT showed only moderate inhibitory effects. viscumTT proved to be more effective than the single extracts and displayed a synergistic effect in vitro and a stronger effect in vivo. viscumTT induced apoptosis via the extrinsic and intrinsic pathways, evidenced by the loss of mitochondrial membrane potential and activation of CASP8 and CASP9. CASP10 inhibitor inhibited apoptosis effectively, emphasising the importance of CASP10 in viscumTT-induced apoptosis. Additionally, viscumTT changed the ratio of apoptosis-associated proteins by downregulation of antiapoptotic proteins such as XIAP and BIRC5, thus shifting the balance towards apoptosis. viscumTT effectively reduced tumour volume in patient-derived xenografts in vivo and may be considered a promising substance for rhabdomyosarcoma therapy.

Garcinol sensitizes breast cancer cells to Taxol through the suppression of caspase-3/iPLA2 and NF-κB/Twist1 signaling pathways in a mouse 4T1 breast tumor model

Breast cancer is a significant threat to women's health and has high incidence and mortality. Metastasis in breast cancer patients is a major cause of cancer deaths among women worldwide. Clinical experience suggests that patients with metastatic triple-negative breast cancer (TNBC) relapse quickly and often have chemotherapy resistance. Taxol (paclitaxel) is an effective chemotherapeutic agent for treating metastatic breast cancer, but Taxol at high doses can cause adverse effects and recurrent resistance. Thus, the selection of a synergistic combination therapy is recommended, which is safer and has a more significant response rate than monotherapy. In this study, our strategy is to combine a low dose of Taxol (5 mg kg^-1, i.p.) and garcinol (1 mg kg^-1, i.g.) to investigate the synergistic antitumor and anti-metastasis effects and to determine the underlying mechanisms of these effects in vivo. For the in vivo study, metastasis-specific mouse mammary carcinoma 4T1 cells were inoculated in Balb/c mice to establish an orthotopic primary tumor and spontaneous metastasis model. Tumor growth and metastases were monitored. The mechanisms of synergistic efficacies were evaluated at different signaling pathways, including proliferation, survival, and epithelial-mesenchymal transition (EMT)-regulated metastatic propensity. We demonstrated that garcinol combined with Taxol significantly increased the therapeutic efficacy when compared with either treatment alone. The synergistic antitumor and anti-metastasis effects were enhanced primarily through the induction of Taxol-stimulated G2/M phase arrest and the inhibition of caspase-3/cytosolic Ca²⁺-independent phospholipase A2 (iPLA₂) and nuclear factor-κB (NF-κB)/Twist-related protein 1 (Twist1) drive downstream events including tumor cell repopulation, survival, inflammation, angiogenesis, invasion, and EMT. Our current findings provide the first experimental evidence that a combination of a low dose of Taxol and garcinol is a promising therapeutic strategy for controlling advanced or metastatic breast cancer. Finally, our results also point to the possible role of NF-κB/Twist1 and caspase-3/iPLA₂ signaling pathways as biomarkers to predict the tumor response to treatment.

Fibronectin-adherent peripheral blood derived mononuclear cells as Paclitaxel carriers for glioblastoma treatment: An in vitro study

BACKGROUND

Glioblastoma (GBM) represents the most aggressive malignant brain tumor in adults, with a risible median life expectancy despite gold standard treatment. Novel drug-delivery methods have been explored. Here we evaluated the possibility to use mononuclear cells (MCs) belonging to the monocytic-dendritic lineage as drug-carrier.

METHODS

MCs were obtained from 10 patients harboring a GBM, and from healthy volunteers, considered as controls. GBM tissue was also obtained from patients. MCs were cultured and the adherent population on fibronectin (FN-MCs), after immunocytochemistry and flow cytometry characterization, was loaded with Paclitaxel (FN-MCs-PTX). Antiproliferative and migration activity of FN-MCs-PTX was evaluated in two-dimensional (2D) and three-dimensional (3D) co-culture assays with red fluorescent U87 Malignant Glioma cells and primary GBM cells. Antiangiogenic properties of FN-MCs-PTX were tested on cultures with endothelial cells.

RESULTS

Phenotypical characterization showed a high expression of monocytic-dendritic markers in GBM cells and FN-MCs. FN-MCs demonstrated to effectively uptake PTX and to strongly inhibit GBM growth in vitro (P <0.01). Moreover, tumor-induced migration of MCs, although partially affected by the PTX cargo, remained statistically significant when compared with unprimed cells and this was confirmed in a 3D Matrigel model (P <0.01) and in a Trans-well assay (P <0.01). FN-MCs-PTX also disclosed considerable antiangiogenic properties.

DISCUSSION

Our results suggest that the fibronectin-adherent population of MCs isolated from peripheral blood can be an effective tool to inhibit GBM growth. Given the relative facility to obtain such cells and the short time needed for their culture and drug loading this approach may have potential as an adjuvant therapy for GBM.

Sulforaphane suppresses the growth of glioblastoma cells, glioblastoma stem cell-like spheroids, and tumor xenografts through multiple cell signaling pathways

OBJECTIVE Defects in the apoptotic machinery and augmented survival signals contribute to drug resistance in glioblastoma (GBM). Moreover, another complexity related to GBM treatment is the concept that GBM development and recurrence may arise from the expression of GBM stem cells (GSCs). Therefore, the use of a multifaceted approach or multitargeted agents that affect specific tumor cell characteristics will likely be necessary to successfully eradicate GBM. The objective of this study was to investigate the usefulness of sulforaphane (SFN)-a constituent of cruciferous vegetables with a multitargeted effect-as a therapeutic agent for GBM. METHODS The inhibitory effects of SFN on established cell lines, early primary cultures, CD133-positive GSCs, GSC-derived spheroids, and GBM xenografts were evaluated using various methods, including GSC isolation and the sphere-forming assay, analysis of reactive oxygen species (ROS) and apoptosis, cell growth inhibition assay, comet assays for assessing SFN-triggered DNA damage, confocal microscopy, Western blot analysis, and the determination of in vivo efficacy as assessed in human GBM xenograft models. RESULTS SFN triggered the significant inhibition of cell survival and induced apoptotic cell death, which was associated with caspase 3 and caspase 7 activation. Moreover, SFN triggered the formation of mitochondrial ROS, and SFN-triggered cell death was ROS dependent. Comet assays revealed that SFN increased single- and double-strand DNA breaks in GBM. Compared with the vehicle control cells, a significantly higher amount of γ-H2AX foci correlated with an increase in DNA double-strand breaks in the SFN-treated samples. Furthermore, SFN robustly inhibited the growth of GBM cell-induced cell death in established cell cultures and early-passage primary cultures and, most importantly, was effective in eliminating GSCs, which play a major role in drug resistance and disease recurrence. In vivo studies revealed that SFN administration at 100 mg/kg for 5-day cycles repeated for 3 weeks significantly decreased the growth of ectopic xenografts that were established from the early passage of primary cultures of GBM10. CONCLUSIONS These results suggest that SFN is a potent anti-GBM agent that targets several apoptosis and cell survival pathways and further preclinical and clinical studies may prove that SFN alone or in combination with other therapies may be potentially useful for GBM therapy.

Cyclin A1 expression and paclitaxel resistance in human ovarian cancer cells

BACKGROUND

The development of intrinsic and acquired resistance to antineoplastic agents is a major obstacle to successful chemotherapy in ovarian cancers. Identification and characterisation of chemoresponse-associated biomarkers are of paramount importance for novel therapeutic development.

METHODS

Global RNA expression profiles were obtained by high-throughput microarray analysis. Cell cycle, proliferation rate, and paclitaxel sensitivity of ovarian cancer cells harbouring cyclin A1-inducible expression construct were compared with and without tetracycline induction, as well as when the cyclin A1 expression was suppressed by short inhibiting RNA (siRNA). Cellular senescence was evaluated by β-galactosidase activity staining.

RESULTS

Global RNA expression profiling and subsequent correlation studies of gene expression level and drug response has identified that elevated expression of cyclin A1 (CCNA1) was significantly associated with cellular resistance to paclitaxel, doxorubicin and 5-fluorouracil. The role of cyclin A1 in paclitaxel resistance was confirmed in ovarian cancer cells that harbour an inducible cyclin A1 expression construct, which showed reduced paclitaxel-mediated growth inhibition and apoptosis when cyclin A1 expression was induced, whereas downregulation of cyclin A1 expression in the same cell lines using cyclin A1-specific siRNAs sensitised the cells to paclitaxel toxicity. However, ovarian cancer cells with ectopic expression of cyclin A1 demonstrated slowdown of proliferation and senescence-associated β-galactosidase activity.

CONCLUSIONS

Our profiling and correlation studies have identified cyclin A1 as one chemoresistance-associated biomarker in ovarian cancer. The results of the characterisation studies suggest that cyclin A1 functions as an oncogene that controls proliferative and survival activities in tumourigenesis and chemoresistance of ovarian cancer.

SPATA4 Counteracts Etoposide-Induced Apoptosis via Modulating Bcl-2 Family Proteins in HeLa Cells

Spermatogenesis associated 4 (SPATA4) is a testis-specific gene first cloned by our laboratory, and plays an important role in maintaining the physiological function of germ cells. Accumulated evidence suggests that SPATA4 might be associated with apoptosis. Here we established HeLa cells that stably expressed SPATA4 to investigate the function of SPATA4 in apoptosis. SPATA4 protected HeLa cells from etoposide-induced apoptosis through the mitochondrial apoptotic pathway, in the way that SPATA4 suppressed decrease of the mitochondrial membrane potential, the release of cytochrome c, and subsequent activation of caspase-9 and -3. We further demonstrated that SPATA4 upregulated anti-apoptotic members of Bcl-2 family proteins, Bcl-2, and downregulated the pro-apoptotic member of Bcl-2 family proteins, Bax. Knockdown of SPATA4 in HeLa/SPATA4 cells could partially rescue expression levels of bcl-2 and bax. In conclusion, SPATA4 protects HeLa cells against etoposide-induced apoptosis through the mitochondrial apoptotic pathway. Our findings provide further evidence that SPATA4 plays a role in regulating apoptosis.

Effects of paclitaxel on permanent head and neck squamous cell carcinoma cell lines and identification of anti-apoptotic caspase 9b

PURPOSE

Paclitaxel is an effective chemotherapeutic agent against various human tumors inducing apoptosis via binding to β-tubulin of microtubules and arresting cells mainly in the G2/M phase of the cell cycle. However, the underlying specific molecular mechanisms of paclitaxel on head and neck squamous cell carcinoma (HNSCC) have not been identified yet.

METHODS

The apoptotic effects and mechanisms of paclitaxel on different permanent HPV-negative HNSCC cell lines (UT-SCC-24A, UT-SCC-24B, UT-SCC-60A and UT-SCC-60B) were determined by flow cytometry assays, polymerase chain reaction analysis, immunofluorescence-based assays and sequencing studies.

RESULTS

Paclitaxel induced a G2/M arrest in HNSCC cell lines followed by an increased amount of apoptotic cells. Moreover, the activation of caspase 8, caspase 10 and caspase 3, and the loss of the mitochondrial outer membrane potential could be observed, whereas an activation of caspase 9 could barely be detected. The efficient activation of caspase 9 was not affected by altered methylation patterns. Our results can show that the promoter region of apoptotic protease activating factor 1 (Apaf-1) was not methylated in the HNSCC cell lines. By sequencing analysis two isoforms of caspase 9, the pro-apoptotic caspase 9 and the anti-apoptotic caspase 9b were identified. The anti-apoptotic caspase 9b is missing the catalytic site and acts as an endogenous inhibitor of apoptosis by blocking the binding of caspase 9 to Apaf-1 to form the apoptosome.

CONCLUSION

Our data indicate the presence of anti-apoptotic caspase 9b in HNSCC, which may serve as a promising target to increase chemotherapeutic apoptosis induction.

New Insights into Potential Prevention and Management Options for Chemotherapy-Induced Peripheral Neuropathy

OBJECTIVE

Neurological complications such as chemotherapy-induced peripheral neuropathy (CIPN) and neuropathic pain are frequent side effects of neurotoxic chemotherapy agents. An increasing survival rate and frequent administration of adjuvant chemotherapy treatments involving neurotoxic agents makes it imperative that accurate diagnosis, prevention, and treatment of these neurological complications be implemented.

METHODS

A consideration was undertaken of the current options regarding protective and treatment interventions for patients undergoing chemotherapy with neurotoxic chemotherapy agent or experience with CIPN. Current knowledge on the mechanism of action has also been identified. The following databases PubMed, the Cochrane Library, Science Direct, Scopus, EMBASE, MEDLINE, CINAHL, CNKI, and Google Scholar were searched for relevant article retrieval.

RESULTS

A range of pharmaceutical, nutraceutical, and herbal medicine treatments were identified that either showed efficacy or had some evidence of efficacy. Duloxetine was the most effective pharmaceutical agent for the treatment of CIPN. Vitamin E demonstrated potential for the prevention of cisplatin-IPN. Intravenous glutathione for oxaliplatin, Vitamin B6 for both oxaliplatin and cisplatin, and omega 3 fatty acids for paclitaxel have shown protection for CIPN. Acetyl-L-carnitine may provide some relief as a treatment option. Acupuncture may be of benefit for some patients and Gosha-jinki-gan may be of benefit for protection from adverse effects of oxaliplatin induced peripheral neuropathy.

CONCLUSIONS

Clinicians and researchers acknowledge that there are numerous challenges involved in understanding, preventing, and treating peripheral neuropathy caused by chemotherapeutic agents. New insights into mechanisms of action from chemotherapy agents may facilitate the development of novel preventative and treatment options, thereby enabling medical staff to better support patients by reducing this debilitating side effect.

Evaluation of genotoxic and apoptotic potential of Hypericum adenotrichum Spach. in vitro

Hypericum adenotrichum Spach. is an endemic plant from Turkey that is also used in folk medicine. In this study, following analyses of its chemical composition, the genotoxic/antigenotoxic effects of the methanol extract of H. adenotrichum in human lymphocyte culture were investigated using in vitro sister chromatid exchange, micronucleus and comet assays. In addition, the anti-growth effect of the extract was investigated in human breast cancer cell lines (MCF-7 and MDA-MB-231) using MTT and ATP viability assays. The mode of cell death was determined using fluorescence microscopy and biochemical methods. We found that the H. adenotrichum extract demonstrated cytotoxic and genotoxic effects in a cell type-dependent manner. At selected doses (125-500 μg/ml), the H. adenotrichum extract exhibited significant genotoxic activity in human lymphocytes, whereas it showed anti-growth effects on cancer cell lines between 0.2 and 100 μg/ml concentrations. The mode of cell death in cancer cells was shown to be apoptosis due to the presence of pyknotic nuclei, the cleavage of poly-(ADP-ribose) polymerase (PARP) and/or the activation of caspase-3. These results suggest that H. adenotrichum might show both cytotoxic and genotoxic effects depending on the cell type. This should be taken into account in its use for therapeutic purposes.

Modulation of expression of heat shock proteins and apoptosis by Flueggea leucopyrus (Willd) decoction in three breast cancer phenotypes

Background

During the past few years, there has been an increasing interest among the Traditional and Folk medical practitioners of Sri Lanka in the use of a decoction prepared from Flueggea leucopyrus (Willd.) for treating various cancers including breast cancer. In the present study, the cytotoxicity of this decoction and its effects on Heat Shock Protein (HSP) expression and apoptosis were compared in three breast cancer phenotypes, to scientifically evaluate if a decoction prepared from F. leucopyrus (Willd.) is useful for the treatment of breast cancer.

Methods

Cytotoxic potential of the F. leucopyrus decoction was determined by evaluating its effects in MCF-7, MDA-MB-231 and SKBR-3 breast cancer cell lines, and MCF-10A (non-cancerous) breast cell line, by use of the Sulphorhodamine (SRB) assay. The effect of the decoction on HSP gene expression in the above cells was evaluated by (a) Real time reverse transcription PCR (RT-PCR) and (b) Immunofluorescence analysis of HSP protein expression. Effects of the decoction on apoptosis were evaluated by (a) fluorescent microscopic examination of apoptosis related morphological changes and (b) DNA fragmentation (c) Caspase 3/7 assay.

Results

F. leucopyrus decoction can mediate significant cytotoxic effects in all three breast cancer cells phenotypes (IC₅₀ values: 27.89, 99.43, 121.43 μg/mL at 24 h post incubation periods, for MCF-7, MDA-MB-231, SKBR-3 respectively) with little effect in the non-cancerous breast cell line MCF-10A (IC₅₀: 570.4 μg/mL). Significant (*P <0.05) inhibitions of HSP 90 and HSP 70 expression were mediated by the decoction in MCF-7 and MDA-MB-231, with little effect in the SKBR-3 cells. Clear apoptotic morphological changes on Acridine orange/Ethidium bromide staining and DNA fragmentation were observed in all three breast cancer cell lines. Caspase 3/7 were significantly (*P <0.05) activated only in MDA-MB-231 and SKBR-3 cells indicating caspase dependent apoptosis in these cells and caspase independent apoptosis in MCF-7 cells.

Conclusions

Modulation of HSP 90 and HSP 70 expressions is a possible mechanism by which the decoction of F. leucopyrus mediates cytotoxic effects MCF-7 and MDA-MB-231 cells. This effect appears to correlate with enhanced apoptosis in these cells. In SKBR-3 cells, mechanisms other than HSP inhibition may be utilized to a greater extent by the decoction to mediate the observed cytotoxic effects. Overall findings suggest that the decoction has the potential to be exploited further for effective treatment of breast cancer.

Mesenchymal stromal cells loaded with paclitaxel induce cytotoxic damage in glioblastoma brain xenografts

INTRODUCTION

The goal of cancer chemotherapy is targeting tumor cells and/or tumor-associated microvessels with the lowest systemic toxicity. Mesenchymal stromal cells (MSCs) are promising vehicles for selective drug delivery due to their peculiar ability to home to pathological tissues. We previously showed that MSCs are able to uptake and subsequently to release the chemotherapeutic compound Paclitaxel (PTX) and to impair the growth of subcutaneous glioblastoma multiforme (GBM) xenografts. Here we used an orthotopic GBM model 1) to assess whether PTX-loaded MSCs (PTX-MSCs) retain a tropism towards the tumor cells in the brain context, and 2) to characterize the cytotoxic damage induced by MSCs-driven PTX release in the tumor microenvironment.

METHODS

U87MG GBM cells were fluorescently labeled with the mCherry protein and grafted onto the brain of immunosuppressed rats. In adjacent brain regions, we injected green fluorescent protein-expressing murine MSCs, either loaded with PTX or unloaded. After 1 week survival, the xenografted brain was assessed by confocal microscopy for PTX-induced cell damage.

RESULTS

Overall, MSCs showed remarkable tropism towards the tumor. In rats grafted with PTX-MSCs, the nuclei of U87MG cells showed changes that are typically induced by PTX, including multi-spindle mitoses, centrosome number alterations, and nuclear fragmentation. Multi-spindle mitoses resulted in multinucleated cells that were significantly higher in tumors co-grafted with PTX-MSCs than in controls. Nuclear changes did not occur in astrocytes and neurons surrounding the tumor.

CONCLUSIONS

MSCs appear particularly suited for anti-neoplastic drug delivery in the brain since PTX-specific damage of GBM cells can be achieved avoiding side effects to the normal tissue.

Effects of microRNA-221/222 on cell proliferation and apoptosis in prostate cancer cells

OBJECTIVE

To investigate the role of miR-221/222 in cell proliferation and apoptosis in human prostate cancer cells, and examine the effects of miR-221/222 on caspase-10 expression.

METHODS

Prostate cancer cells were transfected with miR-221/222 mimics or inhibitors. Cell proliferation was assessed by MTT assay. The expression levels of miR-221/222 were detected with quantitative real-time PCR. Apoptosis was induced with TNF-α/CHX treatment, and evaluated by Hoechst 33342 staining, propidium iodide (PI) flow cytometric analysis, caspase-3 activity measurement, and Western blot analysis. Luciferase activity assay, quantitative real-time PCR, and Western blot were performed to evaluate the effects of miR-221/222 on caspase-10 expression.

RESULTS

Our results showed that miR-221/222 could promote the proliferation of prostate cancer cells, including LNCaP and PC3 cells. After transfection and apoptosis induction, Hoechst 33342 staining and PI flow cytometric assay showed that apoptosis was dramatically decreased in prostate cancer cells treated with miR-221/222 mimics. Moreover, caspase-3 activity was dramatically decreased, and the cleaved forms of caspase-3 were reduced, in the miR-221/222 mimic-treated group. On the contrary, miR-221/222 knockdown sensitized the prostate cancer cells to TNF-α/CHX-induced apoptosis. In addition, a negative correlation was observed between the expressions of miR-221/222 and caspase-10 in prostate cancer cells. miR-221/222 could repress the expression of caspase-10, which was confirmed by the luciferase reporter assay.

CONCLUSION

miR-221/222 promote cell proliferation and repress apoptosis, through suppressing caspase-10, in prostate cancer cells. Our results provide promising evidence for the miRNA-based therapeutic strategy of prostate cancers.

Mechanisms involved in the development of chemotherapy-induced neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and painful condition seen in patients undergoing treatment with common agents such as vincristine, paclitaxel, oxaliplatin and bortezomib. The mechanisms of this condition are diverse, and include an array of molecular and cellular contributions. Current research implicates genetic predispositions to this condition, which then may influence cellular responses to chemotherapy. Processes found to be influenced during CIPN include increased expression of inflammatory mediators, primarily cytokines, which can create cascading effects in neurons and glia. Changes in ion channels and neurotransmission, as well as changes in intracellular signaling and structures have been implicated in CIPN. This review explores these issues and suggests considerations for future research.

The role of individual caspases in cell death induction by taxanes in breast cancer cells

Background

In previous study we showed that caspase-2 plays the role of an apical caspase in cell death induction by taxanes in breast cancer cells. This study deals with the role of other caspases. We tested breast cancer cell lines SK-BR-3 (functional caspase-3) and MCF-7 (nonfunctional caspase-3).

Methods and results

Using western blot analysis we demonstrated the activation of initiator caspase-8 and -9 as well as executioner caspase-6 and -7 in both tested cell lines after application of taxanes (paclitaxel, SB-T-1216) at death-inducing concentrations. Caspase-3 activation was also found in SK-BR-3 cells. Employing specific siRNAs after taxane application, suppression of caspase-3 expression significantly increased the number of surviving SK-BR-3 cells. Inhibition of caspase-7 expression also increased the number of surviving SK-BR-3 and MCF-7 cells. On the other hand, suppression of caspase-8 and caspase-9 expression had no significant effect on cell survival. However, caspase-9 seemed to be involved in the activation of caspase-3 and caspase-7. Caspase-3 and caspase-7 appeared to activate mutually. Furthermore, we observed a significant decrease in mitochondrial membrane potential (flow cytometric analysis) and cytochrome c release (confocal microscopy, western blot after cell fractionation) from mitochondria in SK-BR-3 cells. No such changes were observed in MCF-7 cells after taxane treatment.

Conclusion

We conclude that the activation of apical caspase-2 results in the activation of caspase-3 and -7 without the involvement of mitochondria. Caspase-9 can be activated directly via caspase-2 or alternatively after cytochrome c release from mitochondria. Subsequently, caspase-9 activation can also lead to caspase-3 and -7 activations. Caspase-3 and caspase-7 activate mutually. It seems that there is also a parallel pathway involving mitochondria that can cooperate in taxane-induced cell death in breast cancer cells.

Effect of sun ginseng potentiation on epirubicin and paclitaxel-induced apoptosis in human cervical cancer cells

Background

Sun ginseng (SG), a specific formulation of quality-controlled red ginseng, contains approximately equal amounts of three major ginsenosides (RK1, Rg3, and Rg5), which reportedly has antitumor-promoting activities in animal models.

Methods

MTT assay was used to assess whether SG can potentiate the anticancer activity of epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells; apoptosis status was analyzed by annexin V-FITC and PI and analyzed by flow cytometry; and apoptosis pathway was studied by analysis of caspase-3, -8, and -9 activation, mitochondrial accumulation of Bax and Bak, and cytochrome c release.

Results

SG remarkably enhances cancer cell death induced by epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells. Results of the mechanism study highlighted the cooperation between SG and epirubicin or paclitaxel in activating caspase-3 and -9 but not caspase-8. Moreover, SG significantly increased the mitochondrial accumulation of both Bax and Bak triggered by epirubicin or paclitaxel as well as the subsequent release of cytochrome c in the targeted cells.

Conclusion

SG significantly potentiated the anticancer activities of epirubicin and paclitaxel in a synergistic manner. These effects were associated with the increased mitochondrial accumulation of both Bax and Bak that led to an enhanced cytochrome c release, caspase-9/-3 activation, and apoptosis. Treating cancer cells by combining epirubicin and paclitaxel with SG may prove to be a novel strategy for enhancing the efficacy of the two drug types.