Protective effect of aged garlic extract (AGE) on the apoptosis of intestinal epithelial cells caused by methotrexate

Plant Extracts as Possible Agents for Sequela of Cancer Therapies and Cachexia

Cancer is a leading cause of the death worldwide. Since the National Cancer Act in 1971, various cancer treatments were developed including chemotherapy, surgery, radiation therapy and so forth. However, sequela of such cancer therapies and cachexia are problem to the patients. The primary mechanism of cancer sequela and cachexia is closely related to reactive oxygen species (ROS) and inflammation. As antioxidant properties of numerous plant extracts have been widely reported, plant-derived drugs may have efficacy on managing the sequela and cachexia. In this study, recent seventy-four studies regarding plant extracts showing ability to manage the sequela and cachexia were reviewed. Some plant-derived antioxidants inhibited cancer proliferation and inflammation after surgery and others prevented chemotherapy-induced normal cell apoptosis. Also, there are plant extracts that suppressed radiation-induced oxidative stress and cell damage by elevation of glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and regulation of B-cell lymphoma 2 (BcL-2) and Bcl-2-associated X protein (Bax). Cachexia was also alleviated by inhibition of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) by plant extracts. This review focuses on the potential of plant extracts as great therapeutic agents by controlling oxidative stress and inflammation.

Therapeutic potential of natural plant products and their metabolites in preventing radiation enteropathy resulting from abdominal or pelvic irradiation

Radiation-induced gastrointestinal injury or radiation enteropathy is an imminent risk during radiation therapy of abdominal or pelvic tumors. Despite remarkable technological advancements in image-guided radiation delivery techniques, the risk of intestinal injury after radiotherapy for abdominal or pelvic cancers has not been completely eliminated. The irradiated intestine undergoes varying degrees of adverse structural and functional changes, which can result in transient or long-term complications. The risk of development of enteropathy depends on dose, fractionation, and quality of radiation. Moreover, the patients' medical condition, age, inter-individual sensitivity to radiation and size of the treatment area are also risk factors of radiation enteropathy. Therefore, strategies are needed to prevent radiotherapy-induced undesirable alteration in the gastrointestinal tract. Many natural plant products, by virtue of their plethora of biological activities, alleviate the adverse effects of radiation-induced injury. The current review discusses potential roles and possible mechanisms of natural plant products in suppressing radiation enteropathy. Natural plant products have the potential to suppress intestinal radiation toxicity.

Oral Administration of Surface-Deacetylated Chitin Nanofibers and Chitosan Inhibit 5-Fluorouracil-Induced Intestinal Mucositis in Mice

This study investigated the prophylactic effects of orally administered surface-deacetylated chitin nanofibers (SDACNFs) and chitosan against 5-fluorouracil (5-FU)-induced intestinal mucositis, which is a common side effect of 5-FU chemotherapy. SDACNFs and chitosan abolished histological abnormalities associated with intestinal mucositis and suppressed hypoproliferation and apoptosis of intestinal crypt cells. These results indicate that SDACNF and chitosan are useful agents for preventing mucositis induced by anti-cancer drugs.

A review of complementary therapies for chemotherapy induced gastrointestinal mucositis

Administration of chemotherapy often leads to gastrointestinal mucositis (GIM). GIM manifests as nausea, abdominal pain and diarrhoea in recipients of chemotherapy. GIM is a major complication occurring in approximately 80% of patients receiving 5-flurouracil treatment. These side-effects may become so severe that significant dose reductions are required, ultimately affecting treatment efficacy and patient survival. Complementary and alternative medicine (CAM) is a growing area of public interest. This review will provide an overview of current knowledge of complementary medicinal therapies for chemotherapy induced GIM. An understanding of this evolving literature is useful in discussing these therapies with patients who are considering using them.

Saireito (TJ-114), a Japanese traditional herbal medicine, reduces 5-fluorouracil-induced intestinal mucositis in mice by inhibiting cytokine-mediated apoptosis in intestinal crypt cells

Clinical chemotherapy frequently causes intestinal mucositis as a side effect, which is accompanied by severe diarrhea. We recently showed that the cytokine-mediated apoptotic pathway might be important for the development of intestinal mucositis induced by 5-fluorouracil (5-FU). Saireito, the traditional Japanese herbal (Kampo) medicine, is widely used to treat diarrhea and various inflammatory diseases in Japan. In the present study, we investigated the effect of saireito on 5-FU-induced intestinal mucositis in mice, especially in relation to apoptosis in the intestinal crypt. Male C57BL/6 mice were given 5-FU (50 mg/kg), i.p. once daily for 6 days. Intestinal mucositis was evaluated histochemically. Saireito (100–1000 mg/kg) was administered p.o. twice daily for 6 days. Repeated 5-FU treatment caused severe intestinal mucositis including morphological damage, which was accompanied by body weight loss and diarrhea. Daily administration of saireito reduced the severity of intestinal mucositis in a dose-dependent manner. Body weight loss and diarrhea during 5-FU treatment were also significantly attenuated by saireito administration. The number of apoptotic and caspase-3-activated cells in the intestinal crypt was increased, and was accompanied by up-regulated tumor necrosis factor (TNF)-α and interleukin (IL)-1β mRNA within 24 h of the first 5-FU injection. However, all of these measures were significantly lower after saireito administration. These results suggest that saireito attenuates 5-FU-induced intestinal mucositis. This action may come from the reduction of apoptosis in the intestinal crypt via suppression of the up-regulation of inflammatory cytokines. Therefore, saireito may be clinically useful for the prevention of intestinal mucositis during cancer chemotherapy.

5-HT₃ receptor antagonists ameliorate 5-fluorouracil-induced intestinal mucositis by suppression of apoptosis in murine intestinal crypt cells

BACKGROUND AND PURPOSE

Chemotherapeutic agents, including 5-fluorouracil (5-FU), frequently cause intestinal mucositis resulting in severe diarrhoea and morphological mucosal damage. 5-HT₃ receptor antagonists are clinically effective in the treatment of nausea and emesis during cancer chemotherapy. Therefore we here have examined the effects of 5-HT₃ receptor antagonists on 5-FU-induced intestinal mucositis in mice.

EXPERIMENTAL APPROACH

Intestinal mucositis was induced in male C57BL/6 mice by daily administration of 5-FU (50 mg·kg⁻¹) for 5 days. Effects of 5-HT₃ receptor antagonists, ramosetron (0.01-0.1 mg·kg⁻¹) and ondansetron (5 mg·kg⁻¹), on the accompanying histology, cytokine production and apoptosis were assessed.

KEY RESULTS

Continuous administration of 5-FU to mice caused severe intestinal mucositis, which was histologically characterized by the shortening of villi and destruction of intestinal crypts, accompanied by body weight loss and diarrhoea. Daily ramosetron administration dose-dependently reduced the severity of intestinal mucositis, body weight loss and diarrhoea. Similar beneficial effects were observed with ondansetron. The number of apoptotic, caspase-3- and caspase-8-activated cells increased 24 h after the first 5-FU administration, and these responses were reduced by ramosetron. The up-regulation of TNF-α, IL-1β and IL-6 following 5-FU treatment was also attenuated by ramosetron.

CONCLUSIONS AND IMPLICATIONS

5-HT₃ receptor antagonists ameliorated 5-FU-induced intestinal mucositis in mice, and this action could result from suppression of apoptotic responses in the intestinal crypt cells via inhibition of cytokine expression. Thus, 5-HT₃ receptor antagonists may be useful for preventing not only nausea and emesis but also intestinal mucositis during 5-FU chemotherapy.

The redox state of cytochrome c modulates resistance to methotrexate in human MCF7 breast cancer cells

Background

Methotrexate is a chemotherapeutic agent used to treat a variety of cancers. However, the occurrence of resistance limits its effectiveness. Cytochrome c in its reduced state is less capable of triggering the apoptotic cascade. Thus, we set up to study the relationship among redox state of cytochrome c, apoptosis and the development of resistance to methotrexate in MCF7 human breast cancer cells.

Results

Cell incubation with cytochrome c-reducing agents, such as tetramethylphenylenediamine, ascorbate or reduced glutathione, decreased the mortality and apoptosis triggered by methotrexate. Conversely, depletion of glutathione increased the apoptotic action of methotrexate, showing an involvement of cytochrome c redox state in methotrexate-induced apoptosis. Methotrexate-resistant MCF7 cells showed increased levels of endogenous reduced glutathione and a higher capability to reduce exogenous cytochrome c. Using functional genomics we detected the overexpression of GSTM1 and GSTM4 in methotrexate-resistant MCF7 breast cancer cells, and determined that methotrexate was susceptible of glutathionylation by GSTs. The inhibition of these GSTM isoforms caused an increase in methotrexate cytotoxicity in sensitive and resistant cells.

Conclusions

We conclude that overexpression of specific GSTMs, GSTM1 and GSTM4, together with increased endogenous reduced glutathione levels help to maintain a more reduced state of cytochrome c which, in turn, would decrease apoptosis, thus contributing to methotrexate resistance in human MCF7 breast cancer cells.

Immunomodulatory activity of aged garlic extract against implanted fibrosarcoma tumor in mice

Background:

Garlic is known as a medicinal herb with broad therapeutic properties ranging from antibacterial to anticancer and even anticoagulant.

Aim:

Current study was designed to evaluate antitumor effects of aged garlic extract (AGE) on fibrosarcoma tumor in BALB/c mice.

Materials and Methods:

WEHI-164 fibrosarcoma cells were implanted subcutaneously on day zero into right flank of 40 BALB/c mice aged eight weeks. Mice were randomly categorized in two separate groups: 1^st received AGE (100 mg/kg, intraperitoneally), 2^nd group as control received phosphate buffered saline, (PBS). Treatments were done three times per week. Tumor growth was measured and morbidity was recorded. Subpopulations of CD4+/CD8+ T cells were determined using flow cytometry. WEHI-164 cell specific cytotoxicity of splenocytes and in vitro production of gamma-interferon, (IFN-γ) and Interleukin-4, (IL-4) cytokines were measured.

Results:

The mice received AGE had significantly longer survival time compared to control mice. The inhibitory effect on tumor growth was seen in AGE treated mice. The CD4+/CD8+ ratio and in vitro IFN-γ production of splenocytes were significantly increased in AGE group.

Conclusions:

Administration of AGE resulted in improved immune responses against experimentally implanted fibrosarcoma tumors in BALB/c mice. AGE showed significant effects on inhibition of tumor growth and longevity of survival times.

Bak is a key molecule in apoptosis induced by methanol extracts of Codonopsis lanceolata and Tricholoma matsutake in HSC-2 human oral cancer cells

Since the 5-year survival rate of oral cancer remains low, more effective and non-toxic therapeutic and preventive strategies are required. Certain natural products possess anti-cancer properties. The present study investigated the effects of the methanol extracts of Codonopsis lanceolata (MECI) and Tricholoma matsutake (METM) and identified the molecular target in HSC-2 human oral cancer cells. The results revealed that MECI and METM inhibited growth and induced apoptosis, as demonstrated by poly (ADP-ribose) polymerase (PARP) cleavage and nuclear condensation and fragmentation. The compounds also increased Bak protein expression, while Bax, Bcl-XL and Mcl-1 were not affected. The results of the present study show that MECI and METM induce apoptosis to inhibit tumor growth of HSC-2 cells by modulating the Bak protein and suggest that Codonopsis lanceolata and Tricholoma matsutake are potential anticancer drug candidates for oral cancer.

Potential role of the NADPH oxidase NOX1 in the pathogenesis of 5-fluorouracil-induced intestinal mucositis in mice

Although NADPH oxidase 1 (NOX1) has been shown to be highly expressed in the gastrointestinal tract, the physiological and pathophysiological roles of this enzyme are not yet fully understood. In the present study, we investigated the role of NOX1 in the pathogenesis of intestinal mucositis induced by the cancer chemotherapeutic agent 5-fluorouracil (5-FU) in mice. Intestinal mucositis was induced in Nox1 knockout (Nox1KO) and littermate wild-type (WT) mice via single, daily administration of 5-FU for 5 days. In WT mice, 5-FU caused severe intestinal mucositis characterized by a shortening of villus height, a disruption of crypts, a loss of body weight, and diarrhea. In Nox1KO mice, however, the severity of mucositis was significantly reduced, particularly with respect to crypt disruption. The numbers of apoptotic caspase-3- and caspase-8-activated cells in the intestinal crypt increased 24 h after the first 5-FU administration but were overall significantly lower in Nox1KO than in WT mice. Furthermore, the 5-FU-mediated upregulation of TNF-α, IL-1β, and NOX1 and the production of reactive oxygen species were significantly attenuated in Nox1KO mice compared with that in WT mice. These findings suggest that NOX1 plays an important role in the pathogenesis of 5-FU-induced intestinal mucositis. NOX1-derived ROS production following administration of 5-FU may promote the apoptotic response through upregulation of inflammatory cytokines.

Oxidative insults to neurons and synapse are prevented by aged garlic extract and S-allyl-L-cysteine treatment in the neuronal culture and APP-Tg mouse model

Alzheimer's disease (AD) is one of the most common forms of dementia in the elderly. In AD patients, β-amyloid peptide (Aβ) plaques and neurofibrillary tangles are common features observed in the CNS. Aβ deposition results in the production of reactive oxygen species (ROS) leading to the hyperphosphorylation of tau that are associated with neuronal damage. Cholinesterase inhibitors and a partial NMDA receptor antagonist (memantine) have been identified as potential treatment options for AD. However, clinical studies have found that these drugs fail to prevent the disease progression. From ancient times, garlic (Allium sativum) has been used to treat several diseases. By 'aging' of garlic, some adverse reactions of garlic can be eliminated. Recent findings suggest that 'aged garlic extract' (AGE) may be a therapeutic agent for AD because of its antioxidant and Aβ lowering properties. To date, the molecular properties of AGE have been sparsely studied in vitro or in vivo. The present study tested specific biochemical and molecular effects of AGE in neuronal and AD rodent models. Furthermore, we identified S-allyl-L-cysteine (SAC) as one of the most active chemicals responsible for the AGE-mediated effect(s). We observed significant neuroprotective and neurorescue properties of AGE and one of its ingredients, SAC, from ROS (H(2)O(2))-mediated insults to neuronal cells. Treatment of AGE and SAC were found to protect neuronal cells when they were independently co-treated with ROS. Furthermore, a novel neuropreservation effect of AGE was detected in that pre-treatment with AGE alone protected ∼ 80% neuronal cells from ROS-mediated damage. AGE was also found to preserve pre-synaptic protein synaptosomal associated protein of 25 kDa (SNAP25) from ROS-mediated insult. For example, treatment with 2% AGE containing diet and SAC (20 mg/kg of diet) independently increased (∼70%) levels of SNAP25 and synaptophysin in Alzheimer's amyloid precursor protein-transgenic mice, of which the latter was significantly decreased in AD. Taken together, the neuroprotective, including preservation of pre-synaptic proteins by AGE and SAC can be utilized in future drug development in AD.

Protective role of lipoic acid on methotrexate induced intestinal damage in rabbit model

Methotrexate (MTX), a folate antagonist agent, is mainly used in treatment of malignant tumors and auto immune diseases and affects not only tumor cells, but also gastrointestinal mucosa. The present study was undertaken to determine whether lipoic acid (LA) could ameliorate methotrexate-induced oxidative intestine injury in rabbits. Twenty-one rabbits were randomly assigned into three groups: Group 1 (control group), Group 2 (received 20 mg/kg MTX), Group 3 (received MTX plus LA 75 mg/kg orally). On the 6th day rabbits were anesthetized and intestinal tissue sampled for pathologic and biochemical assessment. The intestinal tissue injury index and malondialdehyde (MDA) levels were lower in MTX+LA group as compared to the MTX group, and tissue glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity were higher in MTX+LA group than in the MTX group (p < 0.05). These findings suggest that co-administration of LA with MTX is associated with reduction in oxidative injury and tissue damage in the intestine. We suggest that lipoic acid may have a protective role in the MTX-induced oxidative injury.

Intervention of alpha-lipoic acid ameliorates methotrexate-induced oxidative stress and genotoxicity: A study in rat intestine

Methotrexate (MTX) is an anti-metabolite, widely used in the cancer chemotherapy and rheumatoid arthritis. However, its long-term clinical use is restricted on account of its severe intestinal toxicity. The present study was aimed to investigate the intestinal toxicity of MTX and the possible protective effect of alpha-lipoic acid (LA) on Sprague-Dawley rats. MTX-induced intestinal toxicity was evaluated at the dose of 2.5mg/kg for short-term (5 days treatment) and 1mg/kg for long-term (5 days in a week for four consecutive weeks treatment) study. The possible protective effect of LA was evaluated in both short- as well as long-term study in a dose-dependent manner. MTX treatment induced diarrhoea and mortality in rats, indicating its severe toxicity in the target organ of investigation, i.e., intestine. Further, the intestinal toxicity of MTX was assessed by evaluating different parameters of oxidative stress, DNA damage, cytotoxicity as well as histological changes. Immunostaining for p53 revealed higher genotoxic assault in the intestinal cells due to MTX treatment. Pretreatment of rats with LA led to significant decrease in the oxidative stress, DNA damage, cellular damage, inflammatory changes and apoptosis as determined by malondialdehyde level, glutathione level, comet assay parameters, histological evaluation, immunostaining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. In the present investigation, we report that LA pretreatment ameliorates MTX-induced intestinal toxicity in rat as evident from the protection against oxidative stress, decrease in DNA damage and protection of cellular morphology as well as improvement in the stool consistency and animal survival rate.

Oxidative stress and enhanced paracellular permeability in the small intestine of methotrexate-treated rats

PURPOSE

We previously demonstrated the increase of reactive oxygen species (ROS) production and myeloperoxidase (MPO) activity in the small intestine of methotrexate (MTX)-treated rats. In the present study, we investigated the role of ROS modulating intestinal mucosal permeability in this damage.

METHOD

MTX (20 mg/kg body weight) was administered to rats intravenously. N-Acetylcysteine (NAC; 80 mg/kg body wt), an antioxidant and a precursor of glutathione (GSH) was administered to rats intraperitoneally to investigate the contribution of ROS to the intestinal permeability enhancement. Intestinal permeability was evaluated by determining that of a poorly absorbable marker, fluorescein isothiocyanate-labeled dextran (FD-4; average molecular mass, 4.4 kDa) using the in vitro everted intestine technique. The occurrence of oxidative stress in the small intestine was assayed by measuring chemiluminescence and thiobarbituric acid reactive substances (TBARS) productions in mucosal homogenates of the small intestine.

RESULTS

The mucosal permeability of FD-4 significantly (p < 0.01) increased in MTX-treated rats compared with control rats, as demonstrated by a twofold increase of FD-4 permeation clearance. This suggests an increase in paracellular permeability. Interestingly, the ROS production was observed preceding the increase of paracellular permeability. Treatment with NAC prevented the MTX-induced ROS production and the increase of paracellular permeability.

CONCLUSIONS

NAC protected the small intestine of rats from MTX-induced change in paracellular permeability, suggesting that ROS played an important role in the enhanced paracellular permeability.