Ara-C induces apoptosis in monkey fibroblast cells

Cytarabine prevents neuronal damage by enhancing AMPK to stimulate PINK1 / Parkin-involved mitophagy in Parkinson's disease model

Parkinson's disease (PD) is a common age-related neurodegenerative disorder, which may be largely due to the mitochondrial dysfunction and impaired mitophagy. Thus, it is of great importance to seek novel therapeutic strategies for PD targeting mitochondrial function and mitophagy. Cytarabine is a marine-derived antimetabolite used in the treatment of acute leukemia, which is also used in the study of the nervous system. In this study, we found that cytarabine pretreatment significantly inhibited the apoptosis and necrosis in the ROT-induced SH-SY5Y cell PD model and reduced the oxidative stress, as evidenced by the reduced MDA levels and the increased levels of SOD, GSH, and total antioxidant capacity. Cytarabine can also enhance mitochondrial vitality, improve mitochondrial respiratory function, and preserve mitochondrial morphology. Cytarabine also enhanced the expression of the mitophagy-related proteins PINK1, Parkin, VDAC1, and DJ-1, and its actions can be reversed by treatment with AMPK inhibitor - Compound C (CC), suggesting that AMPK activation may be involved in cytarabine-enhanced mitophagy. Furthermore, cytarabine can also ameliorate the motor symptoms in the MPTP-induced PD-like mice model, and attenuate the neuropathy in the substantia nigra (SN) of PD mice, while Compound C antagonized cytarabine's beneficial effects. In summary, marine-derived compound cytarabine could resist neurological damage both in vitro and in vivo by activating AMPK to increase PINK1/Parkin-induced mitophagy, serving as a promising disease modulator for treating neurodegenerative disease.

Optimized protocol for the generation of functional human induced-pluripotent-stem-cell-derived dopaminergic neurons

Generation of functional human dopaminergic (DA) neurons from human induced pluripotent stem cells (hiPSCs) is a crucial tool for modeling dopamine-related human diseases and cell replacement therapies. Here, we present a protocol to combine neuralizing transcription factor (NGN2) programming and DA patterning to differentiate hiPSCs into mature and functional induced DA (iDA) neurons. We describe steps from transduction of hiPSCs and neural induction through to differentiation and maturation of near-pure, fully functional iDA neurons within 3 weeks. For complete details on the use and execution of this protocol, please refer to Sheta et al. (2022).1.

Exposure to cytarabine causes side effects on adult development and physiology and induces intestinal damage via apoptosis in Drosophila

Cytarabine (Ara-C) is a widely used drug in acute myeloid leukemia (AML). However, it faces serious challenges in clinical application due to serious side effects such as gastrointestinal disorders and neurologic toxicities. Until now, the mechanism of Ara-C-induced damage is not clear. Here, we used Drosophila melanogaster (fruit fly) as the in vivo model to explore the side effects and mechanism of Ara-C. Our results showed that Ara-C supplementation delayed larval development, reduced lifespan, impaired locomotor capacity, and increased susceptibility to stress response in adult flies. In addition, Ara-C led to the intestinal morphological damage and ROS accumulation in the guts. Moreover, administration of Ara-C promoted gene expressions of Toll pathway, IMD pathway, and apoptotic pathway in the guts. These findings raise the prospects of using Drosophila as in vivo model to rapidly assess chemotherapy-mediated toxicity and efficiently screen the protective drugs.

Effects of an elemental diet to reduce adverse events in patients with esophageal cancer receiving docetaxel/cisplatin/5-fluorouracil: a phase III randomized controlled trial-EPOC 2 (JFMC49-1601-C5)

Background

Oral mucositis (OM) is an unpleasant adverse event in patients receiving chemotherapy. A prospective feasibility study showed that elemental diet (ED), an oral supplement that does not require digestion, may prevent OM. Based on this, we established a central review system for oral cavity assessment by dental oncology specialists blinded to background data. We used this system to elucidate the preventive effect of an ED against OM in patients with esophageal cancer receiving docetaxel, cisplatin, and 5-fluorouracil (DCF) therapy.

Patients and methods

In this phase III, multicenter, parallel-group, controlled trial, patients consuming a normal diet orally were randomly assigned (1 : 1) to receive two cycles of DCF with (group A) or without (group B) an ED (Elental® 160 g/day). We assessed the incidence of grade ≥2 OM evaluated by two reviewers, changes in body weight, prealbumin, C-reactive protein, and DCF completion rate based on ED compliance.

Results

Of the 117 patients randomly assigned to treatment, four failed to start treatment and were excluded from the primary analysis; thus, groups A and B comprised 55 and 58 patients, respectively. There were no significant differences in background characteristics. Grade ≥2 OM was observed in eight (15%) and 20 (34%) patients in groups A and B, respectively (P = 0.0141). Changes in body weight and prealbumin during the two DCF cycles were significantly higher in group A than B (P = 0.0022 and 0.0203, respectively). During the first cycle, changes in C-reactive protein were significantly lower in group A than B (P = 0.0338). In group A (receiving ED), the DCF completion rate was 100% in patients with 100% ED compliance and 70% in patients failing ED completion (P = 0.0046).

Conclusions

The study findings demonstrate that an ED can prevent OM in patients with esophageal cancer receiving chemotherapy.

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Patients receiving docetaxel, cisplatin, and 5-fluorouracil (DCF) chemotherapy commonly develop oral mucositis (OM).

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An elemental diet (ED) was able to prevent OM in patients with esophageal cancer receiving DCF.

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Grade ≥2 OM was observed in 15% of patients receiving the ED versus 34% of those not receiving the ED (P = 0.0141).

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Body weight was maintained in the ED group, and hematologic toxicities were lower, compared with the non-ED group.

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The DCF completion rate significantly correlated with ED compliance (P = 0.0046).

Blood glutamate scavengers increase pro-apoptotic signaling and reduce metastatic melanoma growth in-vivo

Inhibition of extracellular glutamate (Glu) release decreases proliferation and invasion, induces apoptosis, and inhibits melanoma metastatic abilities. Previous studies have shown that Blood-glutamate scavenging (BGS), a novel treatment approach, has been found to be beneficial in attenuating glioblastoma progression by reducing brain Glu levels. Therefore, in this study we evaluated the ability of BGS treatment to inhibit brain metastatic melanoma progression in-vivo. RET melanoma cells were implanted in C56BL/6J mice to induce brain melanoma tumors followed by treatment with BGS or vehicle administered for fourteen days. Bioluminescent imaging was conducted to evaluate tumor growth, and plasma/CSF Glu levels were monitored throughout. Immunofluorescence staining of Ki67 and 53BP1 was used to analyze tumor cell proliferation and DNA double-strand breaks. In addition, we analyzed CD8, CD68, CD206, p-STAT1 and iNOS expression to evaluate alterations in tumor micro-environment and anti-tumor immune response due to treatment. Our results show that BGS treatment reduces CSF Glu concentration and consequently melanoma growth in-vivo by decreasing tumor cell proliferation and increasing pro-apoptotic signaling in C56BL/6J mice. Furthermore, BGS treatment supported CD8⁺ cell recruitment and CD68⁺ macrophage invasion. These findings suggest that BGS can be of potential therapeutic relevance in the treatment of metastatic melanoma.

Oral mucositis: the hidden side of cancer therapy

Inflammation response of epithelial mucosa to chemo- radiotherapy cytotoxic effects leads to mucositis, a painful side effect of antineoplastic treatments. About 40% of the patients treated with chemotherapy develop mucositis; this percentage rises to about 90% for head and neck cancer patients (HNC) treated with both chemo- and radiotherapy. 19% of the latter will be hospitalized and will experience a delay in antineoplastic treatment for high-grade mucositis management, resulting in a reduction of the quality of life, a worse prognosis and an increase in patient management costs. Currently, several interventions and prevention guidelines are available, but their effectiveness is uncertain. This review comprehensively describes mucositis, debating the impact of standard chemo-radiotherapy and targeted therapy on mucositis development and pointing out the limits and the benefits of current mucositis treatment strategies and assessment guidelines. Moreover, the review critically examines the feasibility of the existing biomarkers to predict patient risk of developing oral mucositis and their role in early diagnosis. Despite the expression levels of some proteins involved in the inflammation response, such as TNF-α or IL-1β, partially correlate with mucositis process, their presence does not exclude others mucositis-independent inflammation events. This strongly suggests the need to discover biomarkers that specifically feature mucositis process development. Non-coding RNAs might hold this potential.

Inhibition of caspases protects mice from radiation-induced oral mucositis and abolishes the cleavage of RNA-binding protein HuR

The oral mucosal epithelium is typically insulted during chemotherapy and ionizing radiation (IR) therapy and disposed to mucositis, which creates painful inflammation and ulceration in the oral cavity. Oral mucositis alters gene expression patterns, inhibits cellular growth, and initiates cell death in the oral epithelial compartments. Such alterations are governed by several different factors, including transcription factors, RNA-binding proteins, and microRNAs. IR-induced post-transcriptional regulation of RNA-binding proteins exists but is poorly studied in clinically relevant settings. We herein report that the RNA-binding protein human antigen R (HuR) undergoes cleavage modification by caspase-3 following IR-induced oral mucositis and subsequently promotes the expression of the pro-apoptotic factor BAX (Bcl-2-associated X protein), as well as cell death. Further analyses revealed that the HuR cleavage product-1 (HuR-CP1) directly associates and stabilizes the BAX mRNA and concurrently activates the apoptotic pathway. On the other hand, a noncleavable isoform of HuR promotes the clonogenic capacity of primary oral keratinocytes and decreases the effect of IR-induced cell death. Additionally, specific inhibition of caspase-3 by a compound, NSC321205, increases the clonogenic capacity of primary oral keratinocytes and causes increased basal layer cellularity, thickened mucosa, and elevated epithelial cell growth in the tongues of mice with oral mucositis. This protective effect of NSC321205 is mediated by a decrease in caspase-3 activity and the consequent inhibition of HuR cleavage, which reduces the expression of BAX in mice with IR-induced oral mucositis. Thus, we have identified a new molecular mechanism of HuR in the regulation of mRNA turnover and apoptosis in oral mucositis, and our data suggest that blocking the cleavage of HuR enhances cellular growth in the oral epithelial compartment.

Minocycline protects SH-SY5Y cells from 6-hydroxydopamine by inhibiting both caspase-dependent and -independent programmed cell death

Minocycline, a tetracyclic antibiotic, exerts both antiinflammation by acting on microglia and a direct protection on neurons by inhibiting the apoptotic machinery at various levels. However, we are not aware of any study investigating the effects of minocycline on caspase-independent programmed cell death (PCD) pathways. This study investigated these alternative pathways in SH-SY5Y cells, a human dopaminergic cell line, challenged with 6-hydroxydopamine (6-OHDA). Minocycline exhibited neuroprotection and inhibition of the toxin-induced caspase-3-like activity, DNA fragmentation, and chromatin condensation, hallmarks of apoptosis. Moreover, we revealed that 6-OHDA also activated caspase-independent PCDs (such as paraptosis), which required de novo protein synthesis. Additionally, by separately monitoring caspase-dependent and caspase-independent pathways, we showed that inhibition of apoptosis only partially explained the protective effect of minocycline. Moreover, we observed that minocycline reduced the protein content of cells but, unexpectedly, increased the protein synthesis. These findings suggest that minocycline may actually increase protein degradation, so it may also accelerate the clearance of aberrant proteins. In conclusion, we report for the first time evidence indicating that minocycline may inhibit PCD pathways that are additional to conventional apoptosis.

Time controlled release of arabinofuranosylcytosine (Ara-C) from agarose hydrogels using layer-by-layer assembly: an in vitro study

Experimentally induced axonal regeneration is compromised by glial scar formation arising from leptomeningeal fibroblasts cells in and around the hydrogel scaffold implanted for nerve repair. Strategies are needed to prevent such fibroblastic reactive cell layer formation for enhanced axonal regeneration. Here, we implement the technique of layer-by-layer assembled degradable, hydrogen bonded multilayers on agarose hydrogels to incorporate an anti-mitotic drug (1-β-D-arabinofuranosylcytosine (Ara-C)) within the agarose hydrogels. We show controlled release of Ara-C under physiological conditions over a period of days. The concentrations of Ara-C released from agarose at the different time points were sufficient to inhibit fibroblast growth in vitro, while not adversely affecting the viability of the neuronal cells.

Apoptosis- and necrosis-induced changes in light attenuation measured by optical coherence tomography

Optical coherence tomography (OCT) was used to determine optical properties of pelleted human fibroblasts in which necrosis or apoptosis had been induced. We analysed the OCT data, including both the scattering properties of the medium and the axial point spread function of the OCT system. The optical attenuation coefficient in necrotic cells decreased from 2.2 ± 0.3 mm⁻¹ to 1.3 ± 0.6 mm⁻¹, whereas, in the apoptotic cells, an increase to 6.4 ± 1.7 mm⁻¹ was observed. The results from cultured cells, as presented in this study, indicate the ability of OCT to detect and differentiate between viable, apoptotic, and necrotic cells, based on their attenuation coefficient. This functional supplement to high-resolution OCT imaging can be of great clinical benefit, enabling on-line monitoring of tissues, e.g. for feedback in cancer treatment.

Different viabilities and toxicity types after 6-OHDA and Ara-C exposure evaluated by four assays in five cell lines

Cell viability studies are useful when screening novel drugs for the diseases that are related to either increased cell death or enhanced cell survival. There are numerous assays but the results that they produce are rarely unanimous. Here we compared the performance of (1) morphological microscopic assay with double DNA staining, (2) propidium iodide-digitonin assay, (3) MTT-assay, and (4) ATP-assay in human neuroblastoma (SH-SY5Y), rat glioma (C6), rabbit smooth muscle (SMC), Chinese hamster ovary (CHO) and monkey fibroblast cells (CV1-P) exposed to cytosine arabinoside (Ara-C) and 6-hydroxydopamine (6-OHDA). We found that neuronal SH-SY5Y cells were most sensitive to both toxins and the results in all viability tests correlated well. All the other cell lines were much more resistant, particularly to Ara-C but also to 6-OHDA. Toxicity of the compounds was best revealed by MTT and ATP assays, measuring the metabolic activity of the cells, and only occasionally by morphological observations or with the propidium iodide-digitonin assay which is based on the cell membrane integrity. In this research, Ara-C induced pure apoptosis whereas the toxicity type of 6-OHDA was dose-dependent. The use of several viability tests and cell lines is recommended when studying cell death, particularly apoptosis, and performance of antiapoptotic compounds.

A prolyl oligopeptidase inhibitor, Z-Pro-Prolinal, inhibits glyceraldehyde-3-phosphate dehydrogenase translocation and production of reactive oxygen species in CV1-P cells exposed to 6-hydroxydopamine

We studied the ability of prolyl oligopeptidase (POP) inhibitors, Z-Pro-Prolinal and JTP-4819, to prevent translocation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and formation of reactive oxygen species (ROS), in 6-hydroxydopamine (6-OHDA) and cytosine arabinoside (Ara-C) treated monkey fibroblast (CV1-P) and human neuroblastoma (SH-SY5Y) cells. The cells were pretreated with POP inhibitors (30 min) before addition of toxicants. GAPDH was analyzed by Western hybridization, ROS by fluorescent 2'7'-dichlorodihydro-fluorescein diacetate, and viability by the MTT method. Both toxicants induced GAPDH translocation to the particulate fraction (mitochondria and nuclei). Z-Pro-Prolinal was able to inhibit the translocation in 6-OHDA-exposed CV1-P cells. In SH-SY5Y cells and in JTP-4819 pretreated cells, no prevention of translocation was seen. However, the intensity of GAPDH in cytosolic fraction increased. Both inhibitors blocked 6-OHDA-induced ROS-production to the control level in CV1-P but, not in SH-SY5Y cells, without affecting their viability. In conclusion, POP inhibitors are able to prevent certain cell stress related factors such as ROS production or GAPDH translocation.

The roles of dopamine transporter and Bcl-2 protein in the protection of CV1-P cells from 6-OHDA-induced toxicity

6-Hydroxydopamine (6-OHDA) is widely used to produce an animal model of Parkinson's disease by selectively destroying the catecholaminergic nerve system of the substantia nigra. In our previous studies we noted that dopaminergic neuroblastoma cells (SH-SY5Y) die mostly via apoptosis after exposure to 6-OHDA (< or = 100 microM) but African green monkey fibroblast (CV1-P) cells do not succumb, although in both cell lines there were increased intracellular p53 levels. This study was designed to further investigate the mechanisms underlying the p53 elevation. To test how 6-OHDA penetrates into fibroblast cells and affects p53 levels, we investigated the presence of the dopamine transporter (DAT) in CV1-P cells. We showed by western hybridization that CV1-P cells contain the DAT. The apparent entry of 6-OHDA into fibroblasts was decreased by the DAT inhibitor, 1-(2-bis-(4-fluorophenyl)methoxy)ethyl)-4-(3-phenyl-propyl)piperazine (GBR 12909). Pre-treatment with GBR 12909 decreased the elevation of intracellular ROS to the control level and thus prevented the increase of p53 levels in 6-OHDA-treated CV1-P cells. Moreover, an increase of Bcl-2, an antiapoptotic protein, was detected after 6-OHDA treatment, supporting our previous results where no increase in caspase-3 activity was detected. We suggest that Bcl-2 may block the activation of the caspase cascade and protect CV1-P cells from apoptosis.