Plumbagin induces the apoptosis of drug-resistant oral cancer in vitro and in vivo through ROS-mediated endoplasmic reticulum stress and mitochondrial dysfunction.

BACKGROUND: Oral cancer is one of the leading causes of cancer-related deaths worldwide. Chemotherapy is widely used in the treatment of oral cancer, but its clinical efficacy is limited by drug resistance. Hence, novel compounds capable of overcoming drug-resistance are urgently needed. PURPOSE: Plumbagin (PG), a natural compound isolated from Plumbago zeylanica L, has been used to treat various cancers. In this study, we investigated the anticancer effects of PG on drug-resistant oral cancer (CR-SAS) cells, as well as the underlying mechanism. METHODS: MTT assays were used to evaluate the effect of PG on the viability of CR-SAS cells. Apoptosis and reactive oxygen species (ROS) production by the cells were determined using flow cytometry. Protein expression levels were detected by western blotting. RESULTS: The results show that PG reduces the viability and causes the apoptosis of CR-SAS cells. PG is able to induce intracellular and mitochondrial ROS generation that leads to mitochondrial dysfunction. Furthermore, endoplasmic reticulum (ER) stress was triggered in PG-treated CR-SAS cells. The inhibition of ROS using N-acetylcysteine (NAC) abrogated the PG-induced ER stress and apoptosis, as well as the reduction in cell viability. Meanwhile, similar results were observed both in zebrafish and in murine models of drug-resistant oral cancer. CONCLUSION: Our results indicate that PG induces the apoptosis of CR-SAS cells via the ROS-mediated ER stress pathway and mitochondrial dysfunction. It will be interesting to develop the natural compound PG for the treatment of drug-resistant oral cancer.

Age as a modifier of the effects of chemoradiotherapy with infusional 5-fluorouracil after D2 dissection in gastric cancer.

Adjuvant concurrent chemoradiotherapy (CCRT) is the standard care for patients with resected advanced gastric cancer, but its survival benefits remain undetermined in patients undergoing D2 lymph node dissection (D2 dissection). We evaluated safety and efficacy of adjuvant CCRT with 5-fluorouracil (5-FU) versus chemotherapy alone in 110 gastric cancer patients with D2 dissection treated in Taiwan between January 2009 and January 2013. All the 71 patients receiving adjuvant CCRT were treated with daily infusional 5-FU and radiotherapy. Adjuvant CCRT was associated with higher risks of major hematologic (56.3% vs. 23.8%, p = 0.002) and gastrointestinal (46.9% vs. 14.3%, p = 0.027) toxicities and death (12.5% vs. 0.0%, p = 0.041) in patients above 70 years old, but this was not the case in those ≤70 years of age. Univariate Cox proportional regressions identified adjuvant CCRT as a factor for better overall survival (OS) (hazard ratio [HR]=0.52; 95% confidence interval [CI]: 0.27-0.99) and disease-free survival (DFS) (HR=0.46, 95% CI: 0.24-0.88), but it was not a significant factor for OS or DFS after adjusting for other factors in the multivariate analysis. However, in stratified analyses by age, we found adjuvant CCRT was an independent prognostic factor for better OS (HR=0.07; 95% CI: 0.01-0.38) in patients ≤70 years old, but not in those above 70 years of age. Therefore, it was concluded that age may to be a modifier of the effects of adjuvant CCRT.

Effectiveness of the Multidisciplinary Team Model in Treating Colorectal Cancer.

The multidisciplinary team (MDT) model involves multiple medical professionals providing integrated medical care. Colorectal cancer (CRC) has the highest prevalence of cancer in Taiwan. This study examines and evaluates the survival rates of CRC patients treated under the MDT model. In this retrospective and prospective study, 651 CRC patients were recruited. They were divided into 2 groups: the MDT group and the traditional care (TC) group. The MDT group comprised 326 patients who received care from a MDT. The TC group comprised 325 patients who received care from a TC. The outcome variables were survival rates, follow-up appointment compliance, and 14-day readmission rates. Adopting the MDT model for CRC care increased patient follow-up appointment compliance rates at the first week, first month, and third month (p = .032, p = .007, p = .001, respectively). The model also effectively reduced patients' 14-day readmission rates. The results indicated that the survival rates of the MDT care were superior to those of TC. The adoption of the MDT model to treat CRC effectively enhanced clinical treatment adherence, increased survival rates, and reduced the 14-day readmission rate.

Regulation of Cell and Gene Therapy Medicinal Products in Taiwan.

Owing to the rapid and mature development of emerging biotechnology in the fields of cell culture, cell preservation, and recombinant DNA technology, more and more cell or gene medicinal therapy products have been approved for marketing, to treat serious diseases which have been challenging to treat with current medical practice or medicine. This chapter will briefly introduce the Taiwan Food and Drug Administration (TFDA) and elaborate regulation of cell and gene therapy medicinal products in Taiwan, including regulatory history evolution, current regulatory framework, application and review procedures, and relevant jurisdictional issues. Under the promise of quality, safety, and efficacy of medicinal products, it is expected the regulation and environment will be more flexible, streamlining the process of the marketing approval of new emerging cell or gene therapy medicinal products and providing diverse treatment options for physicians and patients.

Risk of breast cancer recurrence in patients receiving manual lymphatic drainage: a hospital-based cohort study.

BACKGROUND: This retrospective cohort study evaluated whether manual lymphatic drainage (MLD) therapy increases the risk of recurrence of breast cancer. METHODS: We analyzed 1,106 women who were diagnosed with stage 0-3 breast cancer between 2007 and 2011 and experienced remission after surgery and adjuvant therapy. The patients were divided into two groups: group A (n=996), in which patients did not participate in any MLD therapy, regardless of whether they developed breast cancer-related lymphedema (BCRL) after cancer treatment; and group B (n=110), in which patients participated in MLD therapy for BCRL. All patients were monitored until October 2013 to determine whether breast cancer recurrence developed, including local or regional recurrence and distant metastasis. Patients who developed cancer recurrence prior to MLD therapy were excluded from analysis. Risk factors associated with cancer recurrence were evaluated using Cox proportional hazards models. RESULTS: During the monitoring period, 166 patients (15.0%) developed cancer recurrence, including 154 (15.5%) in group A and 12 (10.9%) in group B. The median period from surgery to cancer recurrence was 1.85 (interquartile range 1.18-2.93) years. Independent risk factors for cancer recurrence were tumor histological grading of grade 3, high number (≥3) of axillary lymph node invasion, and a large tumor size (>5 cm). Factors protecting against recurrence were positive progesterone receptor status and receiving radiation therapy. Receiving MLD therapy was not an outcome factor in multivariate analyses (hazard ratio 0.71, 95% confidence interval 0.39-1.29, P=0.259). CONCLUSION: MLD is a gentle procedure that does not increase the risk of breast cancer recurrence in patients who develop BCRL.

Protective effect of caffeic acid on paclitaxel induced anti-proliferation and apoptosis of lung cancer cells involves NF-κB pathway.

Caffeic acid (CA), a natural phenolic compound, is abundant in medicinal plants. CA possesses multiple biological effects such as anti-bacterial and anti-cancer growth. CA was also reported to induce fore stomach and kidney tumors in a mouse model. Here we used two human lung cancer cell lines, A549 and H1299, to clarify the role of CA in cancer cell proliferation. The growth assay showed that CA moderately promoted the proliferation of the lung cancer cells. Furthermore, pre-treatment of CA rescues the proliferation inhibition induced by a sub-IC(50) dose of paclitaxel (PTX), an anticancer drug. Western blot showed that CA up-regulated the pro-survival proteins survivin and Bcl-2, the down-stream targets of NF-κB. This is consistent with the observation that CA induced nuclear translocation of NF-κB p65. Our study suggested that the pro-survival effect of CA on PTX-treated lung cancer cells is mediated through a NF-κB signaling pathway. This may provide mechanistic insights into the chemoresistance of cancer calls.

Structure-activity relationship study of pyridazine derivatives as glutamate transporter EAAT2 activators.

Excitatory amino acid transporter 2 (EAAT2) is the major glutamate transporter and functions to remove glutamate from synapses. A thiopyridazine derivative has been found to increase EAAT2 protein levels in astrocytes. A structure-activity relationship study revealed that several components of the molecule were required for activity, such as the thioether and pyridazine. Modification of the benzylthioether resulted in several derivatives (7-13, 7-15 and 7-17) that enhanced EAAT2 levels by >6-fold at concentrations < 5 µM after 24h. In addition, one of the derivatives (7-22) enhanced EAAT2 levels 3.5-3.9-fold after 24h with an EC(50) of 0.5 µM.

Messenger RNA oxidation occurs early in disease pathogenesis and promotes motor neuron degeneration in ALS.

BACKGROUND: Accumulating evidence indicates that RNA oxidation is involved in a wide variety of neurological diseases and may be associated with neuronal deterioration during the process of neurodegeneration. However, previous studies were done in postmortem tissues or cultured neurons. Here, we used transgenic mice to demonstrate the role of RNA oxidation in the process of neurodegeneration. METHODOLOGY/PRINCIPAL FINDINGS: We demonstrated that messenger RNA (mRNA) oxidation is a common feature in amyotrophic lateral sclerosis (ALS) patients as well as in many different transgenic mice expressing familial ALS-linked mutant copper-zinc superoxide dismutase (SOD1). In mutant SOD1 mice, increased mRNA oxidation primarily occurs in the motor neurons and oligodendrocytes of the spinal cord at an early, pre-symptomatic stage. Identification of oxidized mRNA species revealed that some species are more vulnerable to oxidative damage, and importantly, many oxidized mRNA species have been implicated in the pathogenesis of ALS. Oxidative modification of mRNA causes reduced protein expression. Reduced mRNA oxidation by vitamin E restores protein expression and partially protects motor neurons. CONCLUSION/SIGNIFICANCE: These findings suggest that mRNA oxidation is an early event associated with motor neuron deterioration in ALS, and may be also a common early event preceding neuron degeneration in other neurological diseases.

Increased expression of the glial glutamate transporter EAAT2 modulates excitotoxicity and delays the onset but not the outcome of ALS in mice.

The glial glutamate transporter EAAT2 is primarily responsible for clearance of glutamate from the synaptic cleft and loss of EAAT2 has been previously reported in amyotrophic lateral sclerosis (ALS) and Alzheimer's disease. The loss of functional EAAT2 could lead to the accumulation of extracellular glutamate, resulting in cell death known as excitotoxicity. However, it is still unknown whether it is a primary cause in the cascade leading to neuron degeneration or a secondary event to cell death. The goals of this study were to generate transgenic mice overexpressing EAAT2 and then to cross these mice with the ALS-associated mutant SOD1(G93A) mice to investigate whether supplementation of the loss of EAAT2 would delay or rescue the disease progression. We show that the amount of EAAT2 protein and the associated Na+-dependent glutamate uptake was increased about 2-fold in our EAAT2 transgenic mice. The transgenic EAAT2 protein was properly localized to the cell surface on the plasma membrane. Increased EAAT2 expression protects neurons from L-glutamate induced cytotoxicity and cell death in vitro. Furthermore, our EAAT2/G93A double transgenic mice showed a statistically significant (14 days) delay in grip strength decline but not in the onset of paralysis, body weight decline or life span when compared with G93A littermates. Moreover, a delay in the loss of motor neurons and their axonal morphologies as well as other events including caspase-3 activation and SOD1 aggregation were also observed. These results suggest that the loss of EAAT2 may contribute to, but does not cause, motor neuron degeneration in ALS.

Methyl-beta-cyclodextrin but not retinoic acid reduces EAAT3-mediated glutamate uptake and increases GTRAP3-18 expression.

The Na+-dependent glutamate transporter EAAT3 facilitates glutamate uptake into neurons as well as many other cell types. GTRAP3-18 (JWA, Arl6ip5) is a novel protein that interacts with EAAT3 and negatively modulates EAAT3-mediated glutamate uptake. Previous studies suggest that retinoic acid (RA) decreases Na+-dependent glutamate uptake and increases GTRAP3-18 protein expression. However, the RA used in those studies was complexed with methyl-beta-cyclodextrin (MebetaCD). In the present study we found that MebetaCD, but not RA, significantly reduced Na+-dependent EAAT3-mediated [3H]glutamate uptake in human embryonic kidney 293 (HEK293) cells. MebetaCD also significantly increased GTRAP3-18 protein expression in HEK293 cells as well as in rat hypothalamic neuron cultures. Intracerebroventricular administration of MebetaCD to the mouse brain resulted in a significant increase in GTRAP3-18 immunoreactivity in the hippocampus and cerebral cortex. In conclusion, we have shown that MebetaCD reduces EAAT3-mediated glutamate uptake and induces the expression of GTRAP3-18 protein.

Molecular cloning, gene structure, expression profile and functional characterization of the mouse glutamate transporter (EAAT3) interacting protein GTRAP3-18.

Glutamate is an important amino acid implicated in energy metabolism, protein biosynthesis and neurotransmission. The Na(+)-dependent high-affinity excitatory amino acid transporter EAAT3 (EAAC1) facilitates glutamate uptake into most cells. Recently, a novel rat EAAT3-interacting protein called GTRAP3-18 has been identified by a yeast two-hybrid screening. GTRAP3-18 functions as a negative modulator of EAAT3-mediated glutamate transport. In order to further understand the function and regulation of GTRAP3-18, we cloned the mouse orthologue to GTRAP3-18 and determined its gene structure and its expression pattern. GTRAP3-18 encodes a 188-residue hydrophobic protein whose sequence is highly conserved amongst vertebrates. Mouse and human GTRAP3-18 genes contain three exons separated by two introns. The GTRAP3-18 gene is found on mouse chromosome 6D3 and on human chromosome 3p14, a susceptibility locus for cancer and epilepsy. GTRAP3-18 protein and RNA were found both in neuronal rich regions of the brain and in non-neuronal tissues such as the kidney, heart and skeletal muscle. Mouse GTRAP3-18 inhibited EAAT3-mediated glutamate transport in a dose-dependent manner. These studies show that GTRAP3-18 is a ubiquitously expressed protein that functions as a negative regulator of EAAT3 function.