Modulation of p53 and c-myc in DMBA-Induced Mammary Tumors by Oral Glutamine

Collaboration of Hprt/K-RAS/c-Myc mutation in the oncogenesis of T-lymphocytic leukemia: a comparative study

Aim: Leukemia is a malignant clonal illness stem from the mutations of hematopoietic cells. Acute lymphoblastic leukemia is one of the utmost prevalent kinds of leukemia, is brought on by atypical lymphoid progenitor cell division in the bone marrow. Materials & methods: A comparative study between, titanium Nanoparticle-loaded doxorubicin or cisplatin and lactoferrin-loaded doxorubicin or cisplatin, on 7,12-dimethylbenz[a]-anthracene (DMBA)-induced leukemia was investigated and confirming the hypothesis that messenger RNA of Hprt/K-RAS/c-Myc/SAT-2/P53/JAK-2 is a forthcoming signaling pathways in leukemia. Results: A significant alteration in Hprt, K-RAS, C-Myc, P53, JAK-2 and SAT-2 genes was observed post DMBA intoxication the aforementioned Nanodrugs modulated these signaling pathways. Conclusion: The carrier-loaded drugs triggered cytotoxicity of cancer cells via enhancing drug efficacy and bio-availability.

Prophylactic and curative effects of Carica papaya Linn. pulp extract against carbon tetrachloride-induced hepatotoxicity in male rats

Several chemicals and medications induce cellular damage in various organs of the body by activating reactive substances' metabolism leading to various pathological conditions including liver disease. In this study, we evaluated the prophylactic and curative effects of Carica papaya Linn. pulp water extract (PE) against CCl4-induced rat hepatotoxicity. Five groups of rats were created, control, PE, CCl4, (PE-CCl4): The rats were administered with PE pre and during CCl4 injection, and (PE-CCl4-PE): The rats were administered with PE pre, during, and after CCl4. The markers of oxidative stress ("OS": oxidant and antioxidants), inflammation [nuclear factor-κB, tumor necrosis factor-α, and interleukin-6], fibrosis [transforming growth factor-β], and apoptosis [tumor suppressor gene (p53)] were evaluated. Additionally, liver functions, liver histology, and kidney functions were measured. Also, PE characterization was studied. The results showed that PE, in vitro, has a high antioxidant capacity because of the existence of phenolics, flavonoids, tannins, terpenoids, and minerals. Otherwise, the PE administration [groups (PE-CCl4) and (PE-CCl4-PE)] exhibited its prophylactic and therapeutic role versus the hepatotoxicity induced by CCl4 where PE treatment improved liver functions, liver histopathology, and renal functions by decreasing oxidative stress, inflammation, fibrosis, and apoptosis induced by CCl4. Our study elucidated that PE contains high amounts of phenolics, flavonoids, tannins, terpenoids, and ascorbic acid. So, PE exerted significant prophylactic and curative effects against hepatotoxicity induced by CCl4. These were done by enhancing the markers of antioxidants and drug-metabolizing enzymes with reductions in lipid peroxidation, inflammation, fibrosis, and apoptosis. PE administration for healthful rats for 12 weeks had no negative impacts. Consequently, PE is a promising agent for the prohibition and therapy of the toxicity caused by xenobiotics.

The antioxidant and anti-inflammatory effects of Carica Papaya Linn. seeds extract on CCl4-induced liver injury in male rats

Background

Oxidative stress (OS) and inflammation are the central pathogenic events in liver diseases. In this study, the protective and therapeutic role of Carica Papaya Linn. seeds extract (SE) was evaluated against the hepatotoxicity induced by carbon tetrachloride (CCl₄) in rats.

Methods

The air-dried papaya seeds were powdered and extracted with distilled water. The phytochemical ingredients, minerals, and antioxidant potentials were studied. For determination of the biological role of SE against hepatotoxicity induced by CCl₄, five groups of adult male Sprague-Dawley rats were prepared (8 rats per each): C: control; SE: rats were administered with SE alone; CCl₄: rats were injected subcutaneously with CCl₄; SE-CCl₄ group: rats were administered with SE orally for 2 weeks before and 8 weeks during CCl₄ injection; SE-CCl₄-SE group: Rats were administered with SE and CCl₄ as mentioned in SE-CCl₄ group with a prolonged administration with SE for 4 weeks after the stopping of CCl₄ injection. Then, the markers of OS [lipid peroxidation (LP) and antioxidant parameters; glutathione (GSH), superoxide dismutase (SOD), glutathione-S-transferase (GST), glutathione peroxidase (GPx)], inflammation [nuclear factor (NF)-κB, tumor necrosis factor (TNF)-α, interleukin (IL)-6], fibrosis [transforming growth factor (TGF)-β], apoptosis [tumor suppressor gene (p53)], liver and kidney functions beside liver histopathology were determined.

Results

The phytochemical analyses revealed that SE contains different concentrations of phenolics, flavonoids, terpenoids, and minerals so it has potent antioxidant activities. Therefore, the treatment with SE pre, during, and/or after CCl₄ administration attenuated the OS induced by CCl₄ where the LP was reduced, but the antioxidants (GSH, SOD, GST, and GPx) were increased. Additionally, these treatments reduced the inflammation, fibrosis, and apoptosis induced by CCl₄, since the levels of NF-κB, TNF-α, IL-6, TGF-β, and p53 were declined. Accordingly, liver and kidney functions were improved. These results were confirmed by the histopathological results.

Conclusions

SE has protective and treatment roles against hepatotoxicity caused by CCl₄ administration through the reduction of OS, inflammation, fibrosis, and apoptosis induced by CCl₄ and its metabolites in the liver tissues. Administration of SE for healthy rats for 12 weeks had no adverse effects. Thus, SE can be utilized in pharmacological tools as anti-hepatotoxicity.

Oral glutamine inhibits tumor growth of gastric cancer bearing mice by improving immune function and activating apoptosis pathway

Gastric cancer is one of the most common cancers in the world. It has been shown that exogenous glutamine (GLN) can inhibit the growth of tumor in vivo, but the relationship between GLN and gastric cancer has not been studied. The gastric cancer bearing mouse model was constructed and taken GLN orally at the same time, and the results found that oral GLN (1 or 2 g/kg/d) significantly inhibited the growth rate of tumor and reduce the weight of tumor tissues. Immunohistochemistry showed that oral GLN significantly reduced the PCNA index, which further proved that GLN could inhibit the growth of tumor cells. At the same time, TUNEL assay showed that oral GLN significantly enhanced the apoptosis levels of tumor cells. In addition, GLN reduced GSH levels in tumor tissues, but increased the levels of GSH in plasma, improved the T-lymphocyte transformation rate and NK cell activity, significantly inhibited the secretion of TNF-α and promoted the secretion of IL-2, thus regulating the immune function in vivo. Further detection of apoptosis pathway showed that oral GLN significantly enhanced the expression of pro-apoptotic factor Bad and inhibited the expression of Bcl-2. Meanwhile, GLN significantly increased the activities of Caspase-3, Caspase-8, caspase-9 and PARP. GSH activator NAC had a similar effect to GLN, which could improve the immune function and activate apoptosis pathway, while GSH inhibitor BSO significantly blocked the regulation of GLN, destroyed the immune balance and inhibited apoptosis, but IL-2 significantly blocked the anti-apoptotic effect of BSO. Therefore, oral GLN can improve immune function and activate apoptosis pathway through GSH, and then inhibit the growth of tumor in vivo.

Immune Therapy for Sarcomas

Absolute lymphocyte count (ALC) recovery rapidly occurring at 14 days after start of chemotherapy for osteosarcoma and Ewing sarcoma is a good prognostic factor. Conversely, lymphopenia is associated with significantly decreased sarcoma survival. Clearly, the immune system can contribute towards better survival from sarcoma. This chapter will describe treatment and host factors that influence immune function and how effective local control and systemic interventions of sarcoma therapy can cause inflammation and/or immune suppression but are currently the standard of care. Preclinical and clinical efforts to enhance immune function against sarcoma will be reviewed. Interventions to enhance immune function against sarcoma have included regional therapy (surgery, cryoablation, radiofrequency ablation, electroporation, and radiotherapy), cytokines, macrophage activators (mifamurtide), vaccines, natural killer (NK) cells, T cell receptor (TCR) and chimeric antigen receptor (CAR) T cells, and efforts to decrease inflammation. The latter is particularly important because of new knowledge about factors influencing expression of checkpoint inhibitory molecules, PD1 and CTLA-4, in the tumor microenvironment. Since these molecules can now be blocked using anti-PD1 and anti-CTLA-4 antibodies, how to translate this knowledge into more effective immune therapies in the future as well as how to augment effectiveness of current interventions (e.g., radiotherapy) is a challenge. Barriers to implementing this knowledge include cost of agents that release immune checkpoint blockade and coordination of cost-effective outpatient sarcoma treatment. Information on how to research clinical trial eligibility criteria and how to access current immune therapy trials against sarcoma are shared, too.

Combination between Taxol-Encapsulated Liposomes and Eruca sativa Seed Extract Suppresses Mammary Tumors in Female Rats Induced by 7,12 Dimethylbenz(α)anthracene

Taxol (paclitaxel) is a powerful anti-cancer drug widely used against several types of malignant tumors. Because Taxol may exert several side effects, a variety of formulations have been developed. One of these features liposomes, regarded as one of the most promising drug carriers, biocompatible and best able to reduce drug toxicity without changing efficacy against tumor cells. Eruca sativa seed extract (SE) is considered a promising natural product from cruciferous vegetables against breast cancer, increasing chemotherapeutic and eliminating harmful side effects. The effects of Taxol-encapsulated liposomes (T) alone and in combination between Eruca sativa seed extract on nuclear factor kappa B (NF-κB), cyclooxygenase-2 (COX-2) and B-cell lymphoma-2 (Bcl-2) gene expression levels were investigated in rat mammary gland carcinogenesis induced by 7,12 dimethylbenz(α) anthracene (DMBA) using qRT-PCR. The results showed that DMBA increased NF-κB, COX-2 and Bcl-2 gene expression levels and lipid peroxidation (LP), while decreasing glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities and total antioxidant concentration (TAC) compared to the control group. T and T-SE treatment reduced NF-κB, COX-2 and Bcl-2 gene expression levels and LP. Hence, T and T-SE treatment appeared to reduce inflammation and cell proliferation, while increasing apoptosis, GST and SOD activities and TAC.

Inhibition of NF-κB, Bcl-2 and COX-2 Gene Expression by an Extract of Eruca sativa Seeds during Rat Mammary Gland Carcinogenesis

The effect of Eruca sativa seed extract (SE) on nuclear factor kappa B (NF-κB), cyclooxygenase-2 (COX-2) and B-cell lymphoma-2 (Bcl-2) gene expression levels was investigated in rat mammary gland carcinogenesis induced by 7,12 dimethylbenz(α)anthracene (DMBA). DMBA increased NF-κB, COX-2 and Bcl-2 gene expression levels and lipid peroxidation (LP), while, decreased glutathione-S-transferase (GST) and superoxide dismutase (SOD) activities and total antioxidant concentration (TAC) compared to the control group. After DMBA administration, SE treatment reduced NF-κB, COX-2 and Bcl-2 gene expression levels and LP. Hence, SE treatment reduced inflammation and cell proliferation, while increasing apoptosis, GST and SOD activities and TAC. Analysis revealed that SE has high concentrations of total flavonoids, triterpenoids, alkaloids and polyphenolic compounds such as gallic, chlorogenic, caffeic, 3,4-dicaffeoyl quinic, 3,5-dicaffeoyl quinic, tannic, cinnamic acids, catechin and phloridzin. These findings indicate that SE may be considered a promising natural product from cruciferous vegetables against breast cancer, especially given its high antioxidant properties.

Oncogenes and tumor suppressors regulate glutamine metabolism in cancer cells

Several hallmarks of cancer cells are their display of metabolic changes and enhanced proliferation. Highly proliferating cells utilize glutamine as a source of nitrogen, and therefore, one of the commonly seen metabolic changes is increased glutaminolysis, or glutamine catabolism. In addition, glutamine is an important anaplerotic source by which cells support the pools of TCA cycle intermediates in Myc-expressing cancer cells. Glutamine is converted to aspartate, which forms oxaloacetate, malate, and pyruvate. These conversions increase the NADPH/NADP(+) ratio and maintain redox balance, which supports proliferation in K-ras-expressing cells. Therefore, glutamine is important for cancer cell proliferation and survival. On the other hand, glutamine stimulates the activation of the tumor suppressor p53, which induces apoptosis and tumor regression. The tumor suppressor SIRT4 inhibits glutamate dehydrogenase, which converts glutamic acid to α-ketoglutarate, an intermediate in the TCA cycle. Overall, the expression levels of oncogenes and tumor suppressors are critical to determine whether glutamine supports or suppresses proliferation and survival of cancer cells.

Gene expression analysis of biological systems driving an organotypic model of endometrial carcinogenesis and chemoprevention

An organotypic model of endometrial carcinogenesis and chemoprevention was developed in which normal endometrial organotypic cultures exposed to the carcinogen, DMBA (7,12-dimethylbenz[a]anthracene), developed a cancerous phenotype in the absence, but not presence of subsequent treatment with a flexible heteroarotinoid (Flex-Het), called SHetA2. A discriminant function based on karyometric features of cellular nuclei and an agar clonogenic assay confirmed these histologic changes. Interpretation of microarray data using an internal standard approach identified major pathways associated with carcinogenesis and chemoprevention governed by c-myc, p53, TNFα and Jun genes. Cluster analysis of functional associations of hypervariable genes demonstrated that carcinogenesis is accompanied by a stimulating association between a module of genes that includes tumor necrosis factor α (TNFα), c-myc, and epidermal growth factor-receptor (EGF-R) and a module that includes insulin-like growth factor I-receptor (IGF-IR), p53, and Jun genes. Two secreted proteins involved in these systems, tenascin C and inhibin A, were validated at the protein level. Tenascin C is an EGF-R ligand, and therefore may contribute to the increased EGF-R involvement in carcinogenesis. The known roles of the identified molecular systems in DMBA and endometrial carcinogenesis and chemoprevention supports the validity of this model and the potential clinical utility of SHetA2 in chemoprevention.

Dichotomic actions of glutamine in host versus tumour: an emerging concept

PURPOSE OF REVIEW

Malignancy is characterized by a systemic deficiency of glutamine (GLN). The debate over whether GLN supplementation should be standard of cancer patients is still topical. This review focuses on recent findings on the effect of GLN administration on the incidence and severity of adverse effects in host due to radiotherapy or chemotherapy or both and on its putative adjuvant role on cytotoxicity of radiotherapy and chemotherapy on tumour.

RECENT FINDINGS

Animal and human studies have reported that high-dose GLN supplementation could prevent gastrointestinal tract injury after radiotherapy and chemotherapy. Animal studies are suggesting that GLN could actually decrease tumour growth by upregulating the immune system and through a regulation of the redox status associated to the metabolism of glutathione. GLN could enhance the selectivity of antitumour drugs by protecting normal tissues from chemotherapy and by sensitizing tumour cells to chemotherapy.

SUMMARY

Recent studies have shown that GLN could have dichotomic actions in host versus in tumour, probably in link with glutathione metabolism, suggesting that GLN could be used in clinical practice to increase the therapeutic index of oncological treatments.

Control of mammalian gene expression by amino acids, especially glutamine

Molecular data rapidly accumulating on the regulation of gene expression by amino acids in mammalian cells highlight the large variety of mechanisms that are involved. Transcription factors, such as the basic-leucine zipper factors, activating transcription factors and CCAAT/enhancer-binding protein, as well as specific regulatory sequences, such as amino acid response element and nutrient-sensing response element, have been shown to mediate the inhibitory effect of some amino acids. Moreover, amino acids exert a wide range of effects via the activation of different signalling pathways and various transcription factors, and a number of cis elements distinct from amino acid response element/nutrient-sensing response element sequences were shown to respond to changes in amino acid concentration. Particular attention has been paid to the effects of glutamine, the most abundant amino acid, which at appropriate concentrations enhances a great number of cell functions via the activation of various transcription factors. The glutamine-responsive genes and the transcription factors involved correspond tightly to the specific effects of the amino acid in the inflammatory response, cell proliferation, differentiation and survival, and metabolic functions. Indeed, in addition to the major role played by nuclear factor-kappaB in the anti-inflammatory action of glutamine, the stimulatory role of activating protein-1 and the inhibitory role of C/EBP homology binding protein in growth-promotion, and the role of c-myc in cell survival, many other transcription factors are also involved in the action of glutamine to regulate apoptosis and intermediary metabolism in different cell types and tissues. The signalling pathways leading to the activation of transcription factors suggest that several kinases are involved, particularly mitogen-activated protein kinases. In most cases, however, the precise pathways from the entrance of the amino acid into the cell to the activation of gene transcription remain elusive.

Glutamine prevents DMBA-induced squamous cell cancer

The etiology of oral squamous cell carcinoma has been linked to environmental carcinogens, such as activated aromatic heterocyclic radicals and epoxides. Our previous work on implantable and 7,12-dimethylbenz[a]anthracene (DMBA)-induced breast cancer showed that oral glutamine (GLN) inhibited tumor growth possibly through stimulation of host - and selective inhibition of tumor glutathione (GSH). This finding was associated with up-regulation of NK cell activity, decreased IGF-1 and TGF-beta in the circulation and downregulation of PI-3K/Akt antiapoptotic signaling in tumors. The present study was designed to investigate the effect of topically applied GLN on DMBA-induced hamster buccal pouch squamous cell carcinoma. Histopathological alterations in buccal pouches were studied by light microscopy. GLN and GSH levels in blood and buccal mucosa were determined using specific enzyme assays. The protein expression of bax, bcl-2 and PARP was determined by western blotting. H-ras and p53 genes were examined for presence of mutations using direct DNA sequencing. Fourteen weeks after DMBA application none of the GLN-supplemented animals developed tumors, while all of the control animals had well developed squamous cell carcinomas. The inhibition of DMBA-carcinogenesis by GLN application was associated with increased arterial GLN and GSH, elevated buccal mucosa GSH as well as induction of bax and PARP, and inhibition of bcl-2. H-ras and p53 were wild type. The results from this study in combination with our previous data suggest that the chemopreventive effects of GLN are exerted by enhancing the antioxidant status of the body and activation of apoptosis.