Prevention of cancer cachexia by pyrrolidine dithiocarbamate (PDTC) in colon 26 tumor-bearing mice

Fuzheng Xiaoai Decoction 1 ameliorated cancer cachexia-induced muscle atrophy via Akt-mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Fuzheng Xiaoai Decoction 1 (FZXAD1) is a clinical experience prescription for the treatment of cancer patients at an advanced stage. FZXAD1 has been used for more than 10 years in the clinic and can effectively improve the deficiency syndrome of cancer patients. However, its mechanisms need further clarification.

AIM OF THE STUDY

To check the effects of FZXAD1 in colon 26 (C26) cancer cachexia mice and try to clarify the mechanisms of FZXAD1 in ameliorating cancer cachexia symptoms.

MATERIALS AND METHODS

An animal model of cancer cachexia was constructed with male BALB/c mice bearing C26 tumor cells. Food intake, body weight and tumor size were measured daily during the animal experiment. Tissue samples in different groups including tumor and gastrocnemius muscle, were dissected and weighed at the end of the assay. Serum biochemical indicators such as total protein (TP), glucose (GLU) and alkaline phosphatase (ALP) were also detected. Network pharmacology-based analysis predicted the possible targets and signaling pathways involved in the effects of FZXAD1 on cancer cachexia therapy. Western blotting assays of the gastrocnemius muscle tissues from C26 tumor-bearing mice were then used to confirm the predicted possible targets of FZXAD1.

RESULTS

The results of animal experiments showed that FZXAD1 could ameliorate cancer cachexia by alleviating the muscle wasting as well as kidney atrophy and increasing the body weight of cancer cachexia mice. AKT1, MTOR, MAPK3, HIF1A and MAPK1 were predicted as the core targets of FZXAD1. Western blotting confirmed the prediction that FZXAD1 increased the expression levels of phosphorylated Akt and mTOR in the muscle tissues. In addition, FZXAD1 treatment obviously ameliorated the increased levels of HIF-1α and phosphorylated Erk1/2 in C26 tumor-bearing mice.

CONCLUSION

FZXAD1 effectively ameliorated cancer cachexia in an animal model of mice, which is consistent with its efficacy in the treatment of cancer patients. The mechanisms of FZXAD1 might be mainly based on its alleviating effects on muscle atrophy by activating the Akt-mTOR pathway and thus helping to maintain body weight.

Effects of the anti-oxidant PDTC in combination with a single bout of treadmill running on murine skeletal muscle

Objectives: Skeletal muscle adaptation to physical activity is dependent on various factors. Important signaling mediators are reactive oxygen species (ROS). However, recent research suggests that ROS have both beneficial and deleterious effects on exercise adaptation, dependent on training intensity and training status, so that the question of whether anti-oxidants should be taken in connection with exercise cannot easily be answered. Thus, it is important to gain more insight into the complex roles of ROS in regulating training adaptation.

Methods: The effects of ROS inhibition on skeletal muscle training adaptation were analyzed by applying the anti-oxidant PDTC, which is also an inhibitor of the ROS-activated transcription factor nuclear factor kappa B (NFκB), to juvenile mice in connection with a single bout of treadmill running.

Results: We found that PDTC inhibits exercise-mediated induction of specific stress- and inflammation-associated genes. Other genes, specifically those encoding metabolic and mitochondrial factors, were affected to a lesser extent and there appeared to be little effect on the microRNA (miR) profile.

Discussion: Our data suggest that anti-oxidants regulate distinct sets of adaptation-relevant genes, which might have important implications for the design of exercise-based preventive and therapeutic approaches.

Antioxidant Nanomedicine Significantly Enhances the Survival Benefit of Radiation Cancer Therapy by Mitigating Oxidative Stress-Induced Side Effects

Oxidative stress-induced off-target effects limit the therapeutic window of radiation therapy. Although many antioxidants have been evaluated as radioprotective agents, none of them are in widespread clinical use, owing to the side effects of the antioxidants themselves and the lack of apparent benefit. Aiming for a truly effective radioprotective agent in radiation cancer therapy, the performance of a self-assembling antioxidant nanoparticle (herein denoted as redox nanoparticle; RNP) is evaluated in the local irradiation of a subcutaneous tumor-bearing mouse model. Since RNP is covered with a biocompatible shell layer and possesses a core-shell type structure of several tens of nanometers in size, its lifetime in the systemic circulation is prolonged. Moreover, since 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), one of the most potent antioxidants, is covalently encapsulated in the core of RNP, it exerts intense antioxidant activity and induces fewer adverse effects by avoiding leakage of the TEMPO molecules. Preadministration of RNP to the mouse model effectively mitigates side effects in normal tissues and significantly extends the survival benefit of radiation cancer therapy. Moreover, RNP pretreatment noticeably increases the apoptosis/necrosis ratio of radiation-induced cell death, a highly desirable property to reduce the chronic side effects of ionizing irradiation.

The protection of NF-κB inhibition on kidney injury of systemic lupus erythematosus mice may be correlated with lncRNA TUG1

We aimed to know the effect of nuclear factor-kappa B (NF-κB) inhibition on the kidney injury of systemic lupus erythematosus (SLE) mice. Pristane-induced SLE mice were treated with pyrrolidine dithiocarbamate (PDTC, 50 or 100 mg/kg), a NF-κB inhibitor. Histopathological changes were observed by hematoxylin & eosin, Masson and periodic schiff-methenamine stainings. Long noncoding RNA Taurine upregulated gene 1 (LncRNA TUG1) was measured by real-time reverse transcription PCR, NF-κB p65 expression by western blotting, levels of inflammatory cytokines, antinuclear antibodies (ANA), and antidouble stranded DNA (anti-dsDNA) by enzyme-linked immunosorbent assay, and the deposition of IgG and C3 by immunofluorescence. The kidney of SLE mice exhibited interstitial inflammatory cell infiltration, interstitial fibrous proliferation, glomerular mesangial proliferation, and crescent formation, which was mitigated after PDTC administration. The levels of BUN, Cr, ANA, and anti-dsDNA and the pro-inflammatory factors in SLE mice were increased with obvious deposition of IgG and C3, but they were also reversed by PDTC. Furthermore, the NF-κB p65 expression in the nucleus in the SLE mice was decreased with the up-regulation of TUG1 expression and NF-κB p65 expression in the cytoplasm after PDTC treatment. Correlation analysis revealed the negative correlation between the TUG1 expression and NF-κB p65 in the nucleus in the kidney tissues. NF-κB inhibition with PDTC protected against the kidney injury of pristine-induced SLE mice possibly via up-regulating lncRNA TUG1, and further clinical studies are needed to clarify whether NF-κB inhibition may be a therapeutic modality for the kidney injury of SLE.

Effects of 10 weeks of regular running exercise with and without parallel PDTC treatment on expression of genes encoding sarcomere-associated proteins in murine skeletal muscle

Physical exercise can induce various adaptation reactions in skeletal muscle tissue, such as sarcomere remodeling. The latter involves degradation of damaged sarcomere components, as well as de novo protein synthesis and sarcomere assembly. These processes are controlled by specific protease systems in parallel with molecular chaperones that assist in folding of newly synthesized polypeptide chains and their incorporation into sarcomeres. Since acute exercise induces oxidative stress and inflammation, leading to activation of the transcription factor NFκB (nuclear factor kappa B), we speculated that this transcription factor might also play a role in the regulation of long-term adaptation to regular exercise. Thus, we studied skeletal muscle adaptation to running exercise in a murine model system, with and without parallel treatment with the NFκB-inhibitory, anti-oxidant and anti-inflammatory drug pyrrolidine dithiocarbamate (PDTC). In control mice, 10 weeks of uphill (15° incline) treadmill running for 60 min thrice a week at a final speed of 14 m/min had differential, but only minor effects on many genes encoding molecular chaperones for sarcomere proteins, and/or factors involved in the degradation of the latter. Furthermore, there were marked differences between individual muscles. PDTC treatment modulated gene expression patterns as well, both in sedentary and exercising mice; however, most of these effects were also modest and there was little effect of PDTC treatment on exercise-induced changes in gene expression. Taken together, our data suggest that moderate-intensity treadmill running, with or without parallel PDTC treatment, had little effect on the expression of genes encoding sarcomere components and sarcomere-associated factors in murine skeletal muscle tissue.

Short-term pyrrolidine dithiocarbamate administration attenuates cachexia-induced alterations to muscle and liver in ApcMin/+ mice

Cancer cachexia is a complex wasting condition characterized by chronic inflammation, disrupted energy metabolism, and severe muscle wasting. While evidence in pre-clinical cancer cachexia models have determined that different systemic inflammatory inhibitors can attenuate several characteristics of cachexia, there is a limited understanding of their effects after cachexia has developed, and whether short-term administration is sufficient to reverse cachexia-induced signaling in distinctive target tissues. Pyrrolidine dithiocarbamate (PDTC) is a thiol compound having anti-inflammatory and antioxidant properties which can inhibit STAT3 and nuclear factor κB (NF-κB) signaling in mice. This study examined the effect of short-term PDTC administration to ApcMin/+ mice on cachexia-induced disruption of skeletal muscle protein turnover and liver metabolic function. At 16 weeks of age ApcMin/+ mice initiating cachexia (7% BW loss) were administered PDTC (10mg/kg bw/d) for 2 weeks. Control ApcMin/+ mice continued to lose body weight during the treatment period, while mice receiving PDTC had no further body weight decrease. PDTC had no effect on either intestinal tumor burden or circulating IL-6. In muscle, PDTC rescued signaling disrupting protein turnover regulation. PDTC suppressed the cachexia induction of STAT3, increased mTORC1 signaling and protein synthesis, and suppressed the induction of Atrogin-1 protein expression. Related to cachectic liver metabolic function, PDTC treatment attenuated glycogen and lipid content depletion independent to the activation of STAT3 and mTORC1 signaling. Overall, these results demonstrate short-term PDTC treatment to cachectic mice attenuated cancer-induced disruptions to muscle and liver signaling, and these changes were independent to altered tumor burden and circulating IL-6.

Pyrrolidine Dithiocarbamate (PDTC) Attenuates Cancer Cachexia by Affecting Muscle Atrophy and Fat Lipolysis

Cancer cachexia is a kind of whole body metabolic disorder syndrome accompanied with severe wasting of muscle and adipose tissue. NF-κB signaling plays an important role during skeletal muscle atrophy and fat lipolysis. As an inhibitor of NF-κB signaling, Pyrrolidine dithiocarbamate (PDTC) was reported to relieve cancer cachexia; however, its mechanism remains largely unknown. In our study, we showed that PDTC attenuated cancer cachexia symptom in C26 tumor bearing mice models in vivo without influencing tumor volume. What’s more, PDTC inhibited muscle atrophy and lipolysis in cells models in vitro induced by TNFα and C26 tumor medium. PDTC suppressed atrophy of myotubes differentiated from C2C12 by reducing MyoD and upregulating MuRF1, and preserving the expression of perilipin as well as blocking the activation of HSL in 3T3-L1 mature adipocytes. Meaningfully, we observed that PDTC also inhibited p38 MAPK signaling besides the NF-κB signaling in cancer cachexia in vitro models. In addition, PDTC also influenced the protein synthesis of skeletal muscle by activating AKT signaling and regulated fat energy metabolism by inhibiting AMPK signaling. Therefore, PDTC primarily influenced different pathways in different tissues. The study not only established a simple and reliable screening drugs model of cancer cachexia in vitro but also provided new theoretical basis for future treatment of cancer cachexia.

Pyrrolidine dithiocarbamate ameliorates endothelial dysfunction in thoracic aorta of diabetic rats by preserving vascular DDAH activity

Objective

Endothelial dysfunction plays a pivotal role in the development of diabetic cardiovascular complications. Accumulation of endogenous nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) and inhibition of dimethylarginine dimethylaminohydrolase (DDAH) activity have been involved in diabetic endothelial dysfunction. This study was to investigate the effect of pyrrolidine dithiocarbamate (PDTC) on impairment of endothelium-dependent vasodilatation in diabetic rats and its potential mechanism.

Methods

Diabetic rats were induced by a single intraperitoneal injection of streptozotocin (60mg/kg), and PDTC (10mg/kg) was given in drinking water for 8 weeks. Blood glucose and serum ADMA concentrations were measured in experimental rats. Recombinant adenovirus encoding human DDAH2 gene were constructed and ex vivo transferred to isolated rat aortas. The maximal relaxation (E_max) and half maximal effective concentration (EC₅₀) of aortic rings response to accumulative concentrations of acetylcholine and vascular DDAH activity were examined before and after gene transfection.

Results

Diabetic rats displayed significant elevations of blood glucose and serum ADMA levels compared to control group (P<0.01). Vascular DDAH activity and endothelium-dependent relaxation of aortas were inhibited, as expressed by the decreased E_max and increased EC₅₀ in diabetic rats compared to control rats (P<0.01). Treatment with PDTC not only decreased blood glucose and serum ADMA concentration (P<0.01) but also restored vascular DDAH activity and endothelium-dependent relaxation, evidenced by the higher E_max and lower EC₅₀ in PDTC-treated diabetic rats compared to untreated diabetic rats (P<0.01). Similar restoration of E_max, EC₅₀ and DDAH activity were observed in diabetic aortas after DDAH2-gene transfection.

Conclusions

These results indicate that PDTC could ameliorate impairment of endothelium-dependent relaxation in diabetic rats. The underlying mechanisms might be related to preservation of vascular DDAH activity and consequent reduction of endogenous ADMA in endothelium via its antioxidant action. This study highlights the therapeutic potential of PDTC in impaired vasodilation and provides a new strategy for treatment of diabetic cardiovascular complications.

Liposomal prednisolone phosphate potentiates the antitumor activity of liposomal 5-fluorouracil in C26 murine colon carcinoma in vivo

The antitumor efficacy of 5-fluorouracil (5-FU) in advanced colorectal cancer (CRC) is hindered not only by the low therapeutic index, but also by tumor cell resistance to this cytotoxic drug. Therefore, to enhance the 5-FU antitumor activity, the present research used a novel tumor-targeted therapy based on the co-administration of 5-FU encapsulated in long-circulating liposomes (LCL-5-FU) together with liposomal prednisolone phosphate (LCL-PLP), a formulation with known anti-angiogenic actions on C26 murine colon carcinoma cells. Thus, we assessed the in vivo effects of the combined liposomal drug therapy on C26 carcinoma growth as well as on the production of molecular markers with key roles in tumor development such as angiogenic, inflammatory, and oxidative stress molecules. To get further insight into the polarization state of tumor microenvironment after the treatment, we determined the IL-10/IL-12p70 ratio in tumors. Our results showed that combined liposomal drug therapy inhibited almost totally tumor growth and was superior as antitumor activity to both single liposomal drug therapies tested. The antitumor efficacy of the combined therapy was mainly related to the anti-angiogenic and anti-inflammatory actions on C26 carcinoma milieu, being favored by its controlling effect on intratumor oxidative stress and the skewing of polarization of tumor microenvironmental cells toward their antineoplastic phenotypes. Thus, our study unveils a promising treatment strategy for CRC that should be furthermore considered.

Dual role of macrophages in the response of C26 colon carcinoma cells to 5-fluorouracil administration

Previous studies have demonstrated that tumor-associated macrophages (TAMs) are pivotal players in tumor progression via modulation of tumor angiogenesis, inflammation, metastasis and oxidative stress, as well as of the response of cancer cells to cytotoxic drugs. Nevertheless, the role of TAMs in the prognosis of colorectal cancer remains controversial. Therefore, the present study aimed to investigate how TAMs mediate the response of C26 colon carcinoma cells to the cytotoxic drug 5-fluorouracil (5-FU), upon TAM co-cultivation with these cancer cells in vitro. In this respect, 5-FU cytotoxicity was assessed in C26 cells in standard culture and in a co-culture with peritoneal macrophages, the production of NF-κB was determined by western blot analysis, and the production of angiogenic/inflammatory proteins in each experimental model was evaluated by protein array analysis. To gain further evidence of the effect of TAMs on oxidative stress, malondialdehyde was measured through high-performance liquid chromatography, and the total nonenzymatic antioxidant levels and the production of nitrites were measured through colorimetric assays. The results demonstrated that TAMs exerted a dual role in the response of C26 cells to 5-FU administration in the co-culture model. Thus, on one side, TAMs sensitized C26 cells to 5-FU administration through inhibition of the production of inflammatory and angiogenic proteins in these cancer cells; however, they also protected cancer cells against 5-FU-induced oxidative stress. Collectively, the present findings suggest that the combined administration of 5-FU with pharmacological agents that prevent TAMs to maintain the physiological range of tumor cell oxidative stress may highly improve the therapeutic potential of this drug.

Molecular and cell-based therapies for muscle degenerations: a road under construction

Despite the advances achieved in understanding the molecular biology of muscle cells in the past decades, there is still need for effective treatments of muscular degeneration caused by muscular dystrophies and for counteracting the muscle wasting caused by cachexia or sarcopenia. The corticosteroid medications currently in use for dystrophic patients merely help to control the inflammatory state and only slightly delay the progression of the disease. Unfortunately, walkers and wheel chairs are the only options for such patients to maintain independence and walking capabilities until the respiratory muscles become weak and the mechanical ventilation is needed. On the other hand, myostatin inhibition, IL-6 antagonism and synthetic ghrelin administration are examples of promising treatments in cachexia animal models. In both dystrophies and cachectic syndrome the muscular degeneration is extremely relevant and the translational therapeutic attempts to find a possible cure are well defined. In particular, molecular-based therapies are common options to be explored in order to exploit beneficial treatments for cachexia, while gene/cell therapies are mostly used in the attempt to induce a substantial improvement of the dystrophic muscular phenotype. This review focuses on the description of the use of molecular administrations and gene/stem cell therapy to treat muscular degenerations. It reviews previous trials using cell delivery protocols in mice and patients starting with the use of donor myoblasts, outlining the likely causes for their poor results and briefly focusing on satellite cell studies that raise new hope. Then it proceeds to describe recently identified stem/progenitor cells, including pluripotent stem cells and in relationship to their ability to home within a dystrophic muscle and to differentiate into skeletal muscle cells. Different known features of various stem cells are compared in this perspective, and the few available examples of their use in animal models of muscular degeneration are reported. Since non coding RNAs, including microRNAs (miRNAs), are emerging as prominent players in the regulation of stem cell fates we also provides an outline of the role of microRNAs in the control of myogenic commitment. Finally, based on our current knowledge and the rapid advance in stem cell biology, a prediction of clinical translation for cell therapy protocols combined with molecular treatments is discussed.

Cachectic skeletal muscle response to a novel bout of low-frequency stimulation

While exercise benefits have been well documented in patients with chronic diseases, the mechanistic understanding of cachectic muscle's response to contraction is essentially unknown. We previously demonstrated that treadmill exercise training attenuates the initiation of cancer cachexia and the development of metabolic syndrome symptoms (Puppa MJ, White JP, Velazquez KT, Baltgalvis KA, Sato S, Baynes JW, Carson JA. J Cachexia Sarcopenia Muscle 3: 117-137, 2012). However, cachectic muscle's metabolic signaling response to a novel, acute bout of low-frequency contraction has not been determined. The purpose of this study was to determine whether severe cancer cachexia disrupts the acute contraction-induced response to low-frequency muscle contraction [low-frequency stimulation (LoFS)]. Metabolic gene expression and signaling was examined 3 h after a novel 30-min bout of contraction (10 Hz) in cachectic Apc(Min/+) (Min) and C57BL/6 (BL-6) mice. Pyrrolidine dithiocarbamate, a STAT/NF-κB inhibitor and free radical scavenger, was administered systemically to a subset of mice to determine whether this altered the muscle contraction response. Although glucose transporter-4 mRNA was decreased by cachexia, LoFS increased muscle glucose transporter-4 mRNA in both BL-6 and Min mice. LoFS also induced muscle peroxisome proliferator-activated receptor-γ and peroxisome proliferator-activated receptor-α coactivator-1 mRNA. However, in Min mice, LoFS was not able to induce muscle proliferator-activated receptor-α coactivator-1 targets nuclear respiratory factor-1 and mitochondrial transcription factor A mRNA. LoFS induced phosphorylated-S6 in BL-6 mice, but this induction was blocked by cachexia. Administration of pyrrolidine dithiocarbamate for 24 h rescued LoFS-induced phosphorylated-S6 in cachectic muscle. LoFS increased muscle phosphorylated-AMP-activated protein kinase and p38 in BL-6 and Min mice. These data demonstrate that cachexia alters the muscle metabolic response to acute LoFS, and combination therapies in concert with muscle contraction may be beneficial for improving muscle mass and function during cachexia.

Skeletal muscle glycoprotein 130's role in Lewis lung carcinoma-induced cachexia

Chronic inflammation is associated with cachexia-induced skeletal muscle mass loss in cancer. Levels of IL-6 cytokine family members are increased during cancer-related cachexia and induce intracellular signaling through glycoprotein130 (gp130). Although muscle STAT3 and circulating IL-6 are implicated in cancer-induced muscle wasting, there is limited understanding of muscle gp130's role in this process. Therefore, we investigated the role of skeletal muscle gp130 (skm-gp130) in cancer-induced alterations in the regulation of muscle protein turnover. Lewis lung carcinoma (LLC) cells were injected into 8-wk-old skm-gp130-knockout (KO) mice or wild-type mice. Skeletal muscle loss was attenuated by 16% in gp130-KO mice, which coincided with attenuated LLC-induced phosphorylation of muscle STAT3, p38, and FOXO3. gp130 KO did not restore mTOR inhibition or alter AMP-activated protein kinase (AMPK) expression. The induction of atrogin expression and p38 phosphorylation in C2C12 myotubes exposed to LLC-treated medium was attenuated by gp130 inhibition, but mTOR inhibition was not restored. STAT signaling inhibition in LLC-treated myotubes did not attenuate the induction of p38 or AMPK phosphorylation. We concluded that, during LLC-induced cachexia, skm-gp130 regulates muscle mass signaling through STAT3 and p38 for the activation of FOXO3 and atrogin, but does not directly regulate the suppression of mTOR.

Synergistic cytotoxic effect of sulindac and pyrrolidine dithiocarbamate against ovarian cancer cells

Sulindac, a non-steroidal anti-inflammatory drug, suppresses carcinogenesis and inhibits growth of tumor cells. Pyrrolidine dithiocarbamate (PDTC), a potent NF-κB inhibitor, has been also identified as a potential anti-neoplastic agent. We hypothesized that combination of sulindac and PDTC could result in augmentation of cytotoxicity against ovarian cancer cells. The effect of sulindac and PDTC was examined on several ovarian cancer lines. Tumor cell viability was assessed using the MTT assay. Annexin-V/PI staining was used to detect apoptosis, cell cycle distribution was analyzed in FACS, and expression of cellular proteins was detected by Western blotting. Incubation of OVA-14, OVP-10 and CAOV-1 ovarian cancer cells with sulindac and PDTC resulted in significantly greater inhibition of cell viability compared to either compound alone. In a model of OVA-14 cells it was evident that this effect was not related to the expression of COX enzymes since both active (sulindac sulfide) and inactive (sulindac) in vitro compounds affected the growth of tumor cells to a similar extent and synergized in cytotoxicity with PDTC. Combination of sulindac and PDTC lead to G0 arrest and massive apoptosis in co-treated cultures. Western blotting analysis argued for induction of the mitochondrial apoptotic pathway. These data demonstrate the synergistic cytotoxic effect of sulindac and PDTC on ovarian cancer cells through apoptosis and cell cycle arrest and prompt to test the efficacy of this combination in animal models.

Impact of pyrrolidine dithiocarbamate and interleukin-6 on mammalian target of rapamycin complex 1 regulation and global protein translation

Interleukin-6 (IL-6) is a proinflammatory cytokine that exerts a wide range of cellular, physiological, and pathophysiological responses. Pyrrolidine dithiocarbamate (PDTC) antagonizes the cellular responsiveness to IL-6 through impairment in signal transducer and activator of transcription-3 activation and downstream signaling. To further elucidate the biological properties of PDTC, global gene expression profiling of human HepG2 hepatocellular carcinoma cells was carried out after treatment with PDTC or IL-6 for up to 8 h. Through an unbiased pathway analysis method, gene array analysis showed dramatic and temporal differences in expression changes in response to PDTC versus IL-6. A significant number of genes associated with metabolic pathways, inflammation, translation, and mitochondrial function were changed, with ribosomal protein genes and DNA damage-inducible transcript 4 protein (DDIT4) primarily up-regulated with PDTC but down-regulated with IL-6. Quantitative polymerase chain reaction and Western blot analyses validated the microarray data and showed the reciprocal expression pattern of the mammalian target of rapamycin (mTOR)-negative regulator DDIT4 in response to PDTC versus IL-6. Cell treatment with PDTC resulted in a rapid and sustained activation of Akt and subsequently blocked the IL-6-mediated increase in mTOR complex 1 function through up-regulation in DDIT4 expression. Conversely, down-regulation of DDIT4 with small interfering RNA dampened the capacity of PDTC to block IL-6-dependent mTOR activation. The overall protein biosynthetic capacity of the cells was severely blunted by IL-6 but increased in a rapamycin-independent pathway by PDTC. These results demonstrate a critical effect of PDTC on mTOR complex 1 function and provide evidence that PDTC can reverse IL-6-related signaling via induction of DDIT4.

The role of NF-kappaB in Hepatitis b virus X protein-mediated upregulation of VEGF and MMPs

Hepatitis B virus X protein (HBx) promotes hepatocellular carcinoma (HCC) invasion and metastasis by a poorly understood mechanism. This study investigated the role of NF-kappa B in HBx-mediated upregulation of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs). In a stably expressing HBx cell line, NF-kappa B level was examined by laser scanning confocal microscopy before and after treatment with pyrrolidine dithiocarbamate (PDTC; an NF-kappa B inhibitor). VEGF, MMP2, MMP9, and MMP14 mRNA and protein levels were quantitated by real-time PCR and Western blotting, respectively. HBx stimulated NF-kappa B signaling and increased VEGF, MMP2, MMP9, and MMP14 mRNA and protein levels. PDTC treatment blocked HBx-mediated stimulation of NF-kappa B signaling and decreased VEGF, MMP9, and MMP14 (but not MMP2) mRNA and protein levels. In vivo studies, PDTC reduced angiogenesis in subcutaneous xenograft of nude mice which injected HepG2-HBx cells. This suggests that NF-kappa B is involved in upregulating these genes and in the HBx-mediated invasion and metastasis of HCC.

Inhibition of nuclear factor kappa B attenuates tumour progression in an animal model of renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is a highly metastatic and lethal disease with few efficacious treatments. Many studies have shown that the ubiquitous transcription factor nuclear factor kappa B (NF-kappaB) plays a key role in the development and progression of many cancers including RCC. The aim of this investigation was to evaluate the anti-cancer effect of pyrrolidine dithiocarbamate (PDTC), a NF-kappaB inhibitor, in a murine xenograft model of RCC.

METHODS

The metastatic human RCC cell line, SN12K1, was inoculated into the left kidneys of severe combined immunodeficiency mice and the effect of semi-continuous PDTC treatment (50 mg/kg) on RCC growth analysed 5 weeks later. The analyses carried out in three groups (no treatment, RCC alone and RCC + PDTC) at 5 weeks were: renal weight, protein expression by immunohistochemistry and Western immunoblot, apoptosis (TdT-mediated nick end labelling and morphology) and mitosis (morphology).

RESULTS

PDTC significantly decreased RCC growth and the expression of NF-kappaB subunits (p50, p52, c-Rel and RelB), upstream IKK-beta and IKK-gamma, but did not induce any changes in the expression of IkappaB-alpha and IkappaB-beta. RCC growth was associated with a significant decrease in the expression of the anti-apoptotic proteins Bcl-2 and Bcl-(XL) and increase in pro-apoptotic Bax, all of which were reversed by PDTC. Cell proliferation was significantly reduced by PDTC.

CONCLUSION

The results demonstrate the potential anti-cancer benefits of treating NF-kappaB positive RCCs with NF-kappaB inhibitors like PDTC.

Variation of NF-κB and its effect on immune response in rats with obstructive jaundice

AIM: To investigate the variation of NF-κB and its effect on immune response in rats with obstructive jaundice (OJ).

METHODS: Sixty male Wistar rats were randomized into 3 groups, that is, sham operation group, common bile duct ligation (CBDL) group, and CBDL+PDCT group. Liver histopathology, levels of serum TB, ALT and LPS, liver IL-1β, IL-6, IL-10 and NF-κB were detected at 7 d and 14 d after operation respectively in each group (n = 10).

RESULTS: In CBDL group, all rats were injured with the liver histological damage, in which the level of serum TB, ALT, LPS were all increased as compared with those in SHAM group 7 d and 14 d post-operation (7 d: 140.14 ± 10.17 vs 7.309 ± 1.04, 134.479 ± 10.20 vs 35.79 ± 3.76, 189.33 ± 11.05 vs 2.816 ± 0.58; 14 d: 194.608 ± 12.73 vs 36.142 ± 3.51, 217.797 ± 12.37 vs 7.321 ± 1.03, 292.816 ± 14.53 vs 2.664 ± 0.53, all P < 0.01), besides, expressions of IL-1β, IL-6, IL-10 and NF-κB in liver were increased at day 7 (P < 0.01) and even more significant at day 14 (P < 0.01). After PDTC administration, compared with those in CBDL group, the level of serum TB, ALT as well as the expressions of IL-1β, IL-6 and NF-κB in liver were all significantly decreased at 7 d (P < 0.01), while at 14 d there was no significant difference. However, after PDTC administration, compared with those in CBDL group, there was no significant difference for the level of LPS and IL-10 at both 7 d or 14 d.

CONCLUSION: In the early days (7 d), PDTC does play a protective role in OJ by down-regulating the activation of NF-κB and down-regulating IL-1β and IL-6, so as to alleviate the injuries of liver tissues. While in the late days (14 d), PDTC has no significant effect, which may be caused by LPS, IL-10 and other functional channels.

Central mechanisms controlling appetite and food intake in a cancer setting: an update

PURPOSE OF REVIEW

Cachexia, also known as disease-associated wasting, is an important factor in the mortality of many patients with diseases such as cancer, as well as renal and congestive heart failure. Yet the syndrome is not yet well defined, making diagnosis difficult and often subjective on the part of the physician. Nor are the central mechanisms of cachexia fully elucidated. Recent studies have begun to address these gaps by focusing on three areas: the role of cytokines in cachexia, other proteins and peptides that might be involved, and potential treatments for this devastating syndrome.

RECENT FINDINGS

Cachexia can be caused, in the absence of disease, by inflammatory stimuli and some chemotherapy drugs, suggesting possible central mechanisms in cachexia. Promising treatments include melanocortin antagonism and some hormones.

SUMMARY

While more research is necessary to illuminate causal mechanisms and uncover potential therapies of cachexia, several of its major molecular pathways have become elucidated, suggesting directions for therapeutic approaches.

Sophocarpine and matrine inhibit the production of TNF-alpha and IL-6 in murine macrophages and prevent cachexia-related symptoms induced by colon26 adenocarcinoma in mice

The present study aims to access the effects of sophora alkaloids on the production of pro-inflammatory cytokines and evaluate their therapeutic efficiency on cachexia. The comparative study showed that all sophora alkaloids tested here, including matrine, oxymatrine, sophocarpine, sophoramine, and sophoridine, inhibited TNF-alpha and IL-6 production in both RAW264.7 cells and murine primary macrophages, and sophocarpine showed the most potent inhibitory effect among them. Quantification of TNF-alpha and IL-6 mRNA in RAW264.7 cells by real-time RT-PCR revealed that both sophocarpine and matrine suppressed TNF-alpha and IL-6 expression and sophocarpine has stronger suppressing potency than matrine. Inoculation (s.c.) of colon26 adenocarcinoma cells into BALB/c mice induced cachexia, as evidenced by progressive weight loss, reduction in food intake, wasting of gastrocnemius muscle and epididymal fat, and increase in serum levels of TNF-alpha and IL-6. Administration of 50 mg/kg/d sophocarpine or matrine for 5 days from the onset of cachexia did not inhibit the tumor growth but resulted in attenuation of cachexia symptoms. Furthermore, sophocarpine and matrine decreased the serum levels of TNF-alpha and IL-6, and sophocarpine showed a better therapeutic effect than matrine. These results suggest that sophocarpine and matrine exert anti-cachectic effects probably through inhibition of TNF-alpha and IL-6.

New uses for old copper-binding drugs: converting the pro-angiogenic copper to a specific cancer cell death inducer

BACKGROUND

The conventional approach toward anticancer drug development is a time-consuming and expensive procedure.

OBJECTIVE/METHODS

One approach to expedite this process and achieve more affordable means is to discover new applications of existing drugs, since their pharmacokinetics and pharmacological profiles are well known.

RESULTS

Our encouraging findings in recent studies reveal anticancer activities of several copper-binding ligands including disulfiram (an antialcoholism drug), clioquinol (used to treat Alzheimer's and Huntington's diseases) and diethyldithiocarbamate (an agent for HIV-1 infection treatment).

CONCLUSION

These in vitro and in vivo studies have demonstrated that these archaic drugs can target and react with tumor cellular copper, forming complexes that act as potent proteasome inhibitors and apoptosis inducers.

Transcriptional regulation of the hepatocyte growth factor gene by pyrrolidine dithiocarbamate

Hepatocyte growth factor (HGF) mediates cancer cell invasion and metastasis. This study characterised the down-regulation of HGF expression by pyrrolidine dithiocarbamate (PDTC), which markedly reduced HGF mRNA expression and protein production in MRC-5 cells. Reporter gene studies revealed that PDTC inhibited HGF gene transcription and that the response element is located in the region -75 to +42 bp flanking the transcription initiation site. Electrophoretic mobility shift assay identified three specific protein complexes binding in this region, which were abrogated by exposure of cells to PDTC. PDTC deserves further investigation as a novel therapeutic agent for HGF-driven cancers.

Novel treatments for cancer cachexia

Cancer cachexia is a debilitating and life-threatening syndrome characterised by anorexia, body weight loss, loss of adipose tissue and skeletal muscle, and accounts for > or = 20% of deaths in neoplastic patients. Cancer cachexia significantly impairs quality of life and response to antineoplastic therapies, increasing the morbidity and mortality of cancer patients. Muscle wasting is the most important phenotypic feature of cancer cachexia and the principle cause of function impairment, fatigue and respiratory complications, and is mainly related to a hyperactivation of muscle proteolytic pathways. Existing therapeutic strategies have proven to be only partially effective. In the last decade, the correction of anorexia, the inhibition of catabolic processes and the stimulation of anabolic pathways in muscle has been attempted pharmacologically, giving encouraging results in animal models and through preliminary clinical trials.