Inhibition by isoproterenol and neostigmine of experimental carcinogenesis in rat colon by azoxymethane

Signatures of co-deregulated genes and their transcriptional regulators in colorectal cancer

The deregulated genes in colorectal cancer (CRC) vary significantly across different studies. Thus, a systems biology approach is needed to identify the co-deregulated genes (co-DEGs), explore their molecular networks, and spot the major hub proteins within these networks. We reanalyzed 19 GEO gene expression profiles to identify and annotate CRC versus normal signatures, single-gene perturbation, and single-drug perturbation signatures. We identified the co-DEGs across different studies, their upstream regulating kinases and transcription factors (TFs). Connectivity Map was used to identify likely repurposing drugs against CRC within each group. The functional changes of the co-upregulated genes in the first category were mainly associated with negative regulation of transforming growth factor β production and glomerular epithelial cell differentiation; whereas the co-downregulated genes were enriched in cotranslational protein targeting to the membrane. We identified 17 hub proteins across the co-upregulated genes and 18 hub proteins across the co-downregulated genes, composed of well-known TFs (MYC, TCF3, PML) and kinases (CSNK2A1, CDK1/4, MAPK14), and validated most of them using GEPIA2 and HPA, but also through two signature gene lists composed of the co-up and co-downregulated genes. We further identified a list of repurposing drugs that can potentially target the co-DEGs in CRC, including camptothecin, neostigmine bromide, emetine, remoxipride, cephaeline, thioridazine, and omeprazole. Similar analyses were performed in the co-DEG signatures in single-gene or drug perturbation experiments in CRC. MYC, PML, CDKs, CSNK2A1, and MAPKs were common hub proteins among all studies. Overall, we identified the critical genes in CRC and we propose repurposing drugs that could be used against them.

β adrenergic receptor modulated signaling in glioma models: promoting β adrenergic receptor-β arrestin scaffold-mediated activation of extracellular-regulated kinase 1/2 may prove to be a panacea in the treatment of intracranial and spinal malignancy and extra-neuraxial carcinoma

Neoplastically transformed astrocytes express functionally active cell surface β adrenergic receptors (βARs). Treatment of glioma models in vitro and in vivo with β adrenergic agonists variably amplifies or attenuates cellular proliferation. In the majority of in vivo models, β adrenergic agonists generally reduce cellular proliferation. However, treatment with β adrenergic agonists consistently reduces tumor cell invasive potential, angiogenesis, and metastasis. β adrenergic agonists induced decreases of invasive potential are chiefly mediated through reductions in the expression of matrix metalloproteinases types 2 and 9. Treatment with β adrenergic agonists also clearly reduce tumoral neoangiogenesis, which may represent a putatively useful mechanism to adjuvantly amplify the effects of bevacizumab. Bevacizumab is a monoclonal antibody targeting the vascular endothelial growth factor receptor. We may accordingly designate βagonists to represent an enhancer of bevacizumab. The antiangiogenic effects of β adrenergic agonists may thus effectively render an otherwise borderline effective therapy to generate significant enhancement in clinical outcomes. β adrenergic agonists upregulate expression of the major histocompatibility class II DR alpha gene, effectively potentiating the immunogenicity of tumor cells to tumor surveillance mechanisms. Authors have also demonstrated crossmodal modulation of signaling events downstream from the β adrenergic cell surface receptor and microtubular polymerization and depolymerization. Complex effects and desensitization mechanisms of the β adrenergic signaling may putatively represent promising therapeutic targets. Constant stimulation of the β adrenergic receptor induces its phosphorylation by β adrenergic receptor kinase (βARK), rendering it a suitable substrate for alternate binding by β arrestins 1 or 2. The binding of a β arrestin to βARK phosphorylated βAR promotes receptor mediated internalization and downregulation of cell surface receptor and contemporaneously generates a cell surface scaffold at the βAR. The scaffold mediated activation of extracellular regulated kinase 1/2, compared with protein kinase A mediated activation, preferentially favors cytosolic retention of ERK1/2 and blunting of nuclear translocation and ensuant pro-transcriptional activity. Thus, βAR desensitization and consequent scaffold assembly effectively retains the cytosolic homeostatic functions of ERK1/2 while inhibiting its pro-proliferative effects. We suggest these mechanisms specifically will prove quite promising in developing primary and adjuvant therapies mitigating glioma growth, angiogenesis, invasive potential, and angiogenesis. We suggest generating compounds and targeted mutations of the β adrenergic receptor favoring β arrestin binding and scaffold facilitated activation of ERK1/2 may hold potential promise and therapeutic benefit in adjuvantly treating most or all cancers. We hope our discussion will generate fruitful research endeavors seeking to exploit these mechanisms.

Neural plasticity in pancreatitis and pancreatic cancer

Pancreatic nerves undergo prominent alterations during the evolution and progression of human chronic pancreatitis and pancreatic cancer. Intrapancreatic nerves increase in size (neural hypertrophy) and number (increased neural density). The proportion of autonomic and sensory fibres (neural remodelling) is switched, and are infiltrated by perineural inflammatory cells (pancreatic neuritis) or invaded by pancreatic cancer cells (neural invasion). These neuropathic alterations also correlate with neuropathic pain. Instead of being mere histopathological manifestations of disease progression, pancreatic neural plasticity synergizes with the enhanced excitability of sensory neurons, with Schwann cell recruitment toward cancer and with central nervous system alterations. These alterations maintain a bidirectional interaction between nerves and non-neural pancreatic cells, as demonstrated by tissue and neural damage inducing neuropathic pain, and activated neurons releasing mediators that modulate inflammation and cancer growth. Owing to the prognostic effects of pain and neural invasion in pancreatic cancer, dissecting the mechanism of pancreatic neuroplasticity holds major translational relevance. However, current in vivo models of pancreatic cancer and chronic pancreatitis contain many discrepancies from human disease that overshadow their translational value. The present Review discusses novel possibilities for mechanistically uncovering the role of the nervous system in pancreatic disease progression.

Nerve-cancer interactions in the stromal biology of pancreatic cancer

Interaction of cancer cells with diverse cell types in the tumor stroma is today recognized to have a fate-determining role for the progression and outcome of human cancers. Despite the well-described interactions of cancer cells with several stromal components, i.e., inflammatory cells, cancer-associated fibroblasts, endothelial cells, and pericytes, the investigation of their peculiar relationship with neural cells is still at its first footsteps. Pancreatic cancer (PCa) with its abundant stroma represents one of the best-studied examples of a malignant tumor with a mutually trophic interaction between cancer cells and the intratumoral nerves embedded in the desmoplastic stroma. Nerves in PCa are a rich source of neurotrophic factors like nerve growth factor (NGF), glial-cell-derived neurotrophic factor (GDNF), artemin; of neuronal chemokines like fractalkine; and of autonomic neurotransmitters like norepinephrine which can all enhance the invasiveness of PCa cells via matrix-metalloproteinase (MMP) upregulation, trigger neural invasion (NI), and activate pro-survival signaling pathways. Similarly, PCa cells themselves provide intrapancreatic nerves with abundant trophic agents which entail a remarkable neuroplasticity, leading to emergence of more routes for NI and cancer spread, to augmented local neuro-surveillance, neural sensitization, and neuropathic pain. The strong correlation of NI with PCa-associated desmoplasia suggests the potential presence of a triangular relationship between nerves, PCa cells, and other stromal partners like myofibroblasts and pancreatic stellate cells which generate tumor desmoplasia. Hence, although not a classical hallmark of human cancers, nerve-cancer interactions can be considered as an indispensable sub-class of cancer-stroma interactions in PCa. The present article provides an overview of the so far known nerve-cancer interactions in PCa and illustrates their ominous role in the stromal biology of human PCa.

Role of dopamine in malignant tumor growth

The regulatory role of dopamine, a monoamine neurotransmitter and/or a neurohormone in controlling the secretion of several anterior pituitary hormones, cardiovascular, and renal functions, has already been extensively used by clinicians for therapeutic purposes. In addition to these important functions of dopamine, some recent reports also indicate its novel role in regulating malignant cell proliferation and controlling immune functions in tumor-bearing animals. Therefore, in this article, we discuss all the relevant information correlating dopamine and malignant tumor growth in order to understand the host-tumor relationship at the level of a neurotransmitter and/or a neurohormone.

Inhibition by the calmodulin antagonist trifluoperazine of experimental hepatocarcinogenesis induced by N-nitrosomorpholine in Sprague-Dawley rats

The effect of the calmodulin antagonist trifluoperazine on hepatocarcinogenesis induced by N-nitrosomorpholine (NNM) and on the ornithine decarboxylase (ODC) activity and labeling index of the liver were investigated in male Sprague-Dawley rats. Rats were given drinking water containing NNM for 8 weeks, and from the beginning of the experiment, received s.c. injections of 15 or 30 mg/kg body weight of trifluoperazine in depot form every other day until the end of the experiment. Preneoplastic and neoplastic lesions staining positively for glutathione-S-transferase, placental type (GST-P) were examined histochemically. In week 16, quantitative histological analysis showed that prolonged administration of 30 mg but not 15 mg/kg body weight of trifluoperazine resulted in significant reductions in the number and percentage area of GST-P-positive hepatic lesions. Trifluoperazine also caused significant decreases in the ODC activity of the liver and in the labeling indices of enzyme-altered lesions and their adjacent hepatocytes. These findings indicate that trifluoperazine inhibits carcinogenesis and suggest that this effect may be closely related to its effect in inhibiting ODC activity and cell proliferation in the enzyme-altered lesions and their adjacent liver.

Chemoprevention by galanin against colon carcinogenesis induced by azoxymethane in Wistar rats

The effects of the neuropeptide galanin on the development of colon tumors induced by azoxymethane (AOM) and on the labeling index of colon epithelial cells were investigated in Wistar rats. Treatment with galanin significantly decreased the incidence of colon tumors at week 45. Galanin did not influence the histological appearance of the colon tumors, but it slightly increased the frequency of sub-mucosal adenocarcinomas. Furthermore, it significantly decreased the labeling index of colon mucosa during and after AOM treatment. These findings indicate that galanin inhibited the development of colon tumors and that this effect may be related to its suppression of colon-epithelial-cell proliferation.

Inhibition of azoxymethane-induced experimental colon carcinogenesis in Wistar rats by 6-hydroxydopamine

The effects of 6-hydroxydopamine (6-OHDA) on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), and on norepinephrine (NE) concentration in the colon wall and the labelling index of the colon mucosa were investigated in Wistar rats. Rats received sub-cutaneous (s.c.) injections of AOM once a week for 10 weeks, and throughout 35 weeks were also given intraperitoneal (i.p.) injections of 6-OHDA. Prolonged administration of 6-OHDA was found to cause a significant reduction in the incidence and number of colon tumors. However, it had no influence on the histological features or depths of involvement of colon tumors and/or adenocarcinomas. Its administration also caused significant decreases in the NE concentration in the colon wall and in the labelling index of the colon mucosa. Our findings indicate that 6-OHDA has a protective effect against colon carcinogenesis, and that the activity of the sympathetic nervous system may have an important influence on colon carcinogenesis.

Enhanced induction of colon carcinogenesis by azoxymethane in Wistar rats fed a low-protein diet

The effects of ad libitum feeding of synthetic, low-protein diets on the incidence, number and histology of colon tumors induced by azoxymethane (AOM), on the norepinephrine concentration in the colon wall tissue and on the labelling index of colon mucosa were investigated in Wistar rats. Rats received 10 weekly injections of 7.4 mg/kg body weight of AOM and were given synthetic diets of equal calorie content containing 25% casein (normal-protein diet), 10% casein (low-protein diet) or 5% casein (very-low-protein diet). Administration of the low- and very-low-protein diets resulted in significant increases in the incidence and number of colon tumors at week 30. However, it did not affect the histology of the colon tumors. The low- and very-low-protein diets also resulted in significant increases in norepinephrine concentration in the proximal and distal portions of the colon wall and in the labelling indices of both parts of the colon mucosa. Our findings indicate that low- and very-low-protein diets enhance colon carcinogenesis and that this may be related to their effects in increasing the norepinephrine level in the colon wall and in stimulating proliferation of colon epithelial cells.

Enhancing effect of ethanol or saké on methylazoxymethanol acetate-initiated large bowel carcinogenesis in ACI/N rats

Effects of ethanol or saké on intestinal carcinogenesis by methylazoxymethanol (MAM) acetate were examined in two experiments. In the first experiment, 39 male ACI/N rats were given two weekly intraperitoneal injections of MAM acetate (25 mg/kg body wt) and divided into two groups, with Group 1 being given 10% ethanol and Group 2 being given distilled water. The incidence of colonic cancer in Group 1 (15/17, 88%) was higher than in Group 2 (9/16, 56%, p = 0.040). Differences in the incidences of rectosigmoidal colonic neoplasms were even more marked (59% vs. 19%, p = 0.019) and their proportion of the total number of large intestinal neoplasms was greater in Group 1 (36%) than in Group 2 (15%, p = 0.046). In the second experiment, 97 female ACI/N rats were divided into 6 groups, with the animals of Groups 1-5 being given MAM acetate (2 times, 25 mg/kg body wt). Rats in Group 6 received saline. The rats received isocaloric drinks: Group 1, saké; Group 2, 50% saké; Groups 3 and 6, 15% ethanol; Group 4, 7.5% ethanol; and Group 5, nonalcoholic water. Incidences of rectosigmoidal colonic neoplasms in Groups 1, 2, and 3 (53%, 46%, and 50%) tended to be higher than in Group 5 (38%). Their proportions of the total number of large intestinal neoplasms in Groups 1 (68%) and 2 (67%) were slightly greater than in Group 5 (45%). The results suggest an enhancing effect of ethanol or saké on rectosigmoidal colonic carcinogenesis.

Enhancement of azoxymethane-induced colon carcinogenesis in spontaneously hypertensive rats

The incidence, number, location, and histological types of colon tumors induced by azoxymethane (AOM) and the tissue norepinephrine concentration of the colon wall were investigated in spontaneously hypertensive (SH) rats and in control normotensive Wistar Kyoto (WKY) rats. All rats received 10 weekly s.c. injections of AOM. At week 30, the incidence of colon tumors were significantly higher in SH than in WKY rats. Colon tumors were chiefly located in the proximal colon in WKY but were found with significant frequency in the distal colon in SH rats. The colon tumors induced were mainly adenocarcinomas, but no significant difference in histological type of adenocarcinoma was found between the 2 strains of rat. At weeks 8 and 30, the norepinephrine concentration and labelling index of the distal colon, but not of the proximal colon, were significantly higher in SH than in WKY rats. These findings indicate that increased sympathetic nervous system activity enhances the development of colon tumors.