Exogenous histamine stimulates colorectal cancer implant growth via immunosuppression in mice

Terfenadine, a histamine H1 receptor antagonist, induces apoptosis by suppressing STAT3 signaling in human colorectal cancer HCT116 cells

Introduction

Colorectal cancer is a highly aggressive and metastatic cancer with inadequate clinical outcomes. Given the crucial role of histamine and histamine receptors in colorectal carcinogenesis, this study aimed at exploring the anticancer effects of terfenadine against colorectal cancer HCT116 cells and elucidate its underlying mechanism.

Methods

Herein, we examined the effect of terfenadine on growth and proliferation of HCT116 cells in vitro and in vivo. Various experimental techniques such as flow cytometry, western blot, immunoprecipitation, luciferase assay were employed to unveil the mechanism of cell death triggered by terfenadine.

Results

Terfenadine markedly attenuated the viability of HCT116 cells by abrogating histamine H1 receptor (H1R) signaling. In addition, terfenadine modulated the balance of Bax and Bcl-2, triggering cytochrome c discharge in the cytoplasm, thereby stimulating the caspase cascade and poly-(ADP-ribose) polymerase (PARP) degradation. Moreover, terfenadine suppressed murine double minute-2 (Mdm2) expression, whereas p53 expression increased. Terfenadine suppressed STAT3 phosphorylation and expression of its gene products by inhibiting MEK/ERK and JAK2 activation in HCT116 cells. Furthermore, treatment with U0126, a MEK inhibitor, and AG490, a JAK2 inhibitor, dramatically diminished the phosphorylations of ERK1/2 and JAK2, respectively, leading to STAT3 downregulation. Likewise, terfenadine diminished the complex formation of MEK1/2 with β-arrestin 2. In addition, terfenadine dwindled the phosphorylation of PKC substrates. Terfenadine administration (10 mg/kg) substantially retarded the growth of HCT116 tumor xenografts in vivo.

Conclusion

Terfenadine induces the apoptosis of HCT116 cells by abrogating STAT3 signaling. Overall, this study supports terfenadine as a prominent anticancer therapy for colorectal cancer.

Guanidines: Synthesis of Novel Histamine H3R Antagonists with Additional Breast Anticancer Activity and Cholinesterases Inhibitory Effect

This study examines the properties of novel guanidines, designed and synthesized as histamine H₃R antagonists/inverse agonists with additional pharmacological targets. We evaluated their potential against two targets viz., inhibition of MDA-MB-231, and MCF-7 breast cancer cells viability and inhibition of AChE/BuChE. ADS10310 showed micromolar cytotoxicity against breast cancer cells, combined with nanomolar affinity at hH₃R, and may represent a promising target for the development of an alternative method of cancer therapy. Some of the newly synthesized compounds showed moderate inhibition of BuChE in the single-digit micromolar concentration ranges. H₃R antagonist with additional AChE/BuChE inhibitory effect might improve cognitive functions in Alzheimer's disease. For ADS10310, several in vitro ADME-Tox parameters were evaluated and indicated that it is a metabolically stable compound with weak hepatotoxic activity and can be accepted for further studies.

Expression pattern and prognostic potential of histamine receptors in epithelial ovarian cancer

PURPOSE

Despite recent advances in the treatment of ovarian cancer (OC), long-term remissions remain scarce. For a targeted approach, prognostic markers are indispensable for predicting survival and treatment response. Given their association with multiple hallmarks of cancer, histamine receptors (HR) are emerging as promising candidates. Here, we investigate their expression pattern and prognostic value in OC.

METHODS

Specimens of 156 epithelial OC patients were collected during cytoreductive surgery at the Department of Obstetrics and Gynecology, LMU, between 1990 and 2002 and combined in a tissue microarray. Immunohistochemical staining of the HR H1, H2, H3 and H4 was quantified by an immunoreactive score and linked with clinico-pathological data by Spearman's correlation. Via ROC curve analysis, optimal cut-off values for potential prognostic markers were defined. Overall survival (OS) was visualized in Kaplan-Maier curves and significances determined by log-rank testing. A Cox regression model was applied for multivariate analysis.

RESULTS

HR H3 and H4 expression was restricted to the cytosol of OC cells, while H1 was also present in the nucleus. A significant association between HR H1, H3 and H4 expression with several clinico-pathological parameters was revealed. In addition, HR H1 and H3 expression correlated positively, HR H4 expression negatively with OS. In addition, HR H3 was identified as independent prognostic marker for OS. HR H2 expression had no prognostic value.

CONCLUSIONS

HR H1, H3 and H4 could serve as potential predictors for OS of OC patients. Further research is warranted to elucidate their pathophysiologic role and their predictive and therapeutic potential in OC.

Histamine in cancer immunology and immunotherapy. Current status and new perspectives

Cancer is the second leading cause of death globally and its incidence and mortality are rapidly increasing worldwide. The dynamic interaction of immune cells and tumor cells determines the clinical outcome of cancer. Immunotherapy comes to the forefront of cancer treatments, resulting in impressive and durable responses but only in a fraction of patients. Thus, understanding the characteristics and profiles of immune cells in the tumor microenvironment (TME) is a necessary step to move forward in the design of new immunomodulatory strategies that can boost the immune system to fight cancer. Histamine produces a complex and fine-tuned regulation of the phenotype and functions of the different immune cells, participating in multiple regulatory responses of the innate and adaptive immunity. Considering the important actions of histamine-producing immune cells in the TME, in this review we first address the most important immunomodulatory roles of histamine and histamine receptors in the context of cancer development and progression. In addition, this review highlights the current progress and foundational developments in the field of cancer immunotherapy in combination with histamine and pharmacological compounds targeting histamine receptors.

Apigenin Inhibits the Histamine-Induced Proliferation of Ovarian Cancer Cells by Downregulating ERα/ERβ Expression

Background

Apigenin (APG), a natural flavonoid, can affect the development of a variety of tumors, but its role in ovarian cancer remains unclear. There has been an increasing amount of evidence supporting the vital role played by mast cells and the bioactive mediators they release, as components of the tumor microenvironment, in the progression of ovarian cancer (OC); however, the mechanism warrants further exploration.

Methods and Results

In this study, a combination of transcriptomics analysis and application of TCGA database was performed, and we found that the expression of genes related to mast cell degranulation in ovarian cancer tissues changed remarkably. We then explored whether histamine, a major constituent of mast cell degranulation, could affect the development of ovarian cancer through immunohistochemistry analysis and cell proliferation assays. The results showed that a certain concentration of histamine promoted the proliferation of ovarian cancer cells by upregulating the expression of estrogen receptor α (ERα)/estrogen receptor β (ERβ). Additionally, we found that the inhibition of ERα or the activation of ERβ could inhibit the proliferation of ovarian cancer cells induced by histamine through real-time PCR and western blot assays. Finally, we demonstrated the attenuation effect imparted by apigenin in histamine-mediated ovarian cancer via the PI3K/AKT/mTOR signaling pathway.

Conclusion

Our research revealed that apigenin decelerated ovarian cancer development by downregulating ER-mediated PI3K/AKT/mTOR expression, thus providing evidence of its applicability as a potentially effective therapeutic agent for ovarian cancer treatment.

Pathophysiological Roles of Histamine Receptors in Cancer Progression: Implications and Perspectives as Potential Molecular Targets

High levels of histamine and histamine receptors (HRs), including H1R~H4R, are found in many different types of tumor cells and cells in the tumor microenvironment, suggesting their involvement in tumor progression. This review summarizes the latest evidence demonstrating the pathophysiological roles of histamine and its cognate receptors in cancer biology. We also discuss the novel therapeutic approaches of selective HR ligands and their potential prognostic values in cancer treatment. Briefly, histamine is highly implicated in cancer development, growth, and metastasis through interactions with distinct HRs. It also regulates the infiltration of immune cells into the tumor sites, exerting an immunomodulatory function. Moreover, the effects of various HR ligands, including H1R antagonists, H2R antagonists, and H4R agonists, on tumor progression in many different cancer types are described. Interestingly, the expression levels of HR subtypes may serve as prognostic biomarkers in several cancers. Taken together, HRs are promising targets for cancer treatment, and HR ligands may offer novel therapeutic potential, alone or in combination with conventional therapy. However, due to the complexity of the pathophysiological roles of histamine and HRs in cancer biology, further studies are warranted before HR ligands can be introduced into clinical settings.

N-Substituted piperazine derivatives as potential multitarget agents acting on histamine H3 receptor and cancer resistance proteins

Taking into account that multidrug resistance (MDR) is the main cause for chemotherapeutic failure in cancer treatment, the ability of novel histamine H₃ receptor ligands to reverse the cancer MDR was evaluated, using the ABCB1 efflux pump inhibition assay in mouse MDR T-lymphoma cells. The most active compounds displayed significant cytotoxic and antiproliferative effects as well as a very potent MDR efflux pump inhibitory action, 3-5-fold stronger than that of reference inhibitor verapamil. Although these compounds possess weak antagonistic properties against histamine H₃ receptors, they are valuable pharmacological tools in the search for novel anticancer molecules. Furthermore, for the most active compounds, an insight into mechanisms of action using either, the luminescent Pgp-Glo™ Assay in vitro or docking studies to human Pgp, was performed.

Histamine receptors and cancer pharmacology: an update

In the present review, we will discuss the recent advances in the understanding of the role of histamine and histamine receptors in cancer biology. The controversial role of the histaminergic system in different neoplasias including gastric, colorectal, oesophageal, oral, pancreatic, liver, lung, skin, blood and breast cancers will be reviewed. The expression of histamine receptor subtypes, with special emphasis on the histamine H4 receptor, in different cell lines and human tumours, the signal transduction pathways and the associated biological responses as well as the in vivo treatment of experimental tumours with pharmacological ligands will be described. The presented evidence demonstrates that histamine regulates cancer-associated biological processes during cancer development in multiple cell types, including neoplastic cells and cells in the tumour micro-environment. The outcome will depend on tumour cell type, the level of expression of histamine receptors, signal transduction associated with these receptors, tumour micro-environment and histamine metabolism, reinforcing the complexity of cancer disease. Findings show the pivotal role of H4 receptors in the development and progression of many types of cancers, and considering its immunomodulatory properties, the H4 receptor appears to be the most promising molecular therapeutic target for cancer treatment within the histamine receptor family. Furthermore, the H4 receptor is differentially expressed in tumours compared with normal tissues, and in most cancer types in which data are available, H4 receptor expression is associated with clinicopathological characteristics, suggesting that H4 receptors might represent a novel cancer biomarker. LINKED ARTICLES: This article is part of a themed section on New Uses for 21st Century. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.3/issuetoc.

Cimetidine and Clobenpropit Attenuate Inflammation-Associated Colorectal Carcinogenesis in Male ICR Mice

Histamine and histamine receptors (Hrhs) have been identified as critical molecules during inflammation and carcinogenesis. This study was conducted to determine the effects of Hrh1-Hrh3 antagonists on inflammation-associated colorectal carcinogenesis. Male ICR mice were treated with azoxymethane (AOM, 10 mg/kg bw, i.p.) and 1.5% dextran sodium sulfate (DSS, drinking water for 7 days) to induce colorectal carcinogenesis. The mice were then fed diets containing test chemical (500 ppm terfenadine, 500 ppm cimetidine or 10 ppm clobenpropit) for 15 weeks. At week 18, feeding with the diets containing cimetidine (Hrh2 antagonist) and clobenpropit (Hrh3 antagonist/inverse agonist) significantly lowered the multiplicity of colonic adenocarcinoma. Terfenadine (Hrh1 antagonist) did not affect AOM-DSS-induced colorectal carcinogenesis. Adenocarcinoma cells immunohistochemically expressed Hrh1, Hrh2, Hrh3 and Hrh4 with varied intensities. Because clobenpropit is also known to be a Hrh4 receptor agonist, Hrh2, Hrh3 and Hrh4 may be involved in inflammation-related colorectal carcinogenesis. Additional data, including the mRNA expression of pro-inflammatory cytokines and inducible inflammatory enzymes in the colonic mucosa, are also presented.

Histamine receptors and cancer pharmacology

Considerable evidence has been collected indicating that histamine can modulate proliferation of different normal and malignant cells. High histamine biosynthesis and content together with histamine receptors have been reported in different human neoplasias including melanoma, colon and breast cancer, as well as in experimental tumours in which histamine has been postulated to behave as an important paracrine and autocrine regulator of proliferation. The discovery of the human histamine H(4) receptor in different tissues has contributed to our understanding of histamine role in numerous physiological and pathological conditions revealing novel functions for histamine and opening new perspectives in histamine pharmacology research. In the present review we aimed to briefly summarize current knowledge on histamine and histamine receptor involvement in cancer before focusing on some recent evidence supporting the novel role of histamine H(4) receptor in cancer progression representing a promising molecular target and avenue for cancer drug development.

Cytokine responses of intraepithelial lymphocytes are regulated by histamine H(2) receptor

BACKGROUND

Histamine participates in the immune regulation of several gastrointestinal diseases. However, the effect of histamine on intestinal intraepithelial lymphocytes (IELs), the front line of the intestinal mucosal immune system, is not well understood. We examined whether histamine has a direct effect on cytokine production by IELs and the involvement of histamine receptor subtypes.

METHODS

Murine IELs were activated by PMA plus ionomycin with/without histamine. Secreted cytokines were measured and compared with those of splenocytes. Intracellular cytokines were detected by flow cytometry. Expression of histamine receptor subtypes in IELs was examined by RT-PCR.

RESULTS

Histamine H(1) receptor (H(1)R), H(2)R, and H(4)R, but not H(3)R mRNA were expressed on IELs. Histamine significantly decreased Th1-cytokine (IFN-gamma, TNF-alpha, and IL-2) and also IL-4 production in IELs as well as splenocytes. The selective H(2)R antagonist famotidine, but not the H(1)R antagonist pyrilamine nor the H(3)R/H(4)R antagonist thioperamide, competes with the inhibitory effect of histamine on these cytokine production in IELs. These suppressive effects of histamine were mimicked by a selective H(2)R/H(4)R agonist dimaprit. Further, these suppressive effects of histamine for Th1-cytokine and IL-4 did not accompany the enhancement of IL-10 production or IL-10 mRNA level in IELs. Intracellular cytokine analysis revealed that the number of IFN-gamma-producing alphabeta T cells was significantly reduced by histamine in IELs.

CONCLUSIONS

Histamine has a direct suppressive effect on IEL-derived cytokines via H(2)R, which would have a crucial role in the suppression of local immunoregulation in the intestinal epithelium.

Decreased expression of histamine H1 and H4 receptors suggests disturbance of local regulation in human colorectal tumours by histamine

Production of histamine in colon tumours has been described earlier. Histamine-mediated signals have been shown to be implicated in tumour growth, and the effects of histamine are largely determined locally by the histamine receptor expression pattern. We analysed histamine receptor expression in human colorectal cancer, adenoma and normal mucosa by quantitative reverse transcription-polymerase chain reaction (RT-PCR), Western blot analysis and immunostaining. Real-time RT-PCR results revealed significantly decreased (p<0.001) H1R and H4R mRNA levels in tumours compared to normal colonic mucosa, without any significant change in H2R mRNA expression. H3R was absent in most samples; it was detected at low levels in 7.9% of the cases. Protein analysis showed a similar decrease in histamine receptor expression in carcinoma and adenoma compared to normal mucosa controls. Based on these results, we performed further Western blot analysis on Dukes-classified and -selected tumour samples. We found significantly decreased H4R levels in neoplastic samples compared to normal colonic tissue, but there was no significant correlation between histamine receptor expression profile and the Dukes stage of tumours. Immunohistochemical staining revealed expression patterns of H1R, H2R and H4R similar to those suggested by the mRNA and Western blot results. In the present study, we demonstrate that H1R, H2R and H4R are expressed in colon carcinoma and the adjacent normal mucosa. The results suggest a dramatic alteration in the distribution of histamine receptors in colon cancer. These findings raise the perspective of targeted pharmacological studies with selective histamine receptor antagonists or agonists in the therapy of colorectal tumours.

Impact of systemic histamine deficiency on the crosstalk between mammary adenocarcinoma and T cells

The purpose of the present study was to investigate the influence of lack of histamine (HA) on tumor growth and functions of T cells in order further to illustrate the mechanism of immunological tolerance induction by HA. We assessed the phenotype and cytokine production of splenic lymphocytes in syngeneic HA-free (histidine decarboxylase knock-out) (HDC KO) and wild-type mice, inoculated subcutaneously with the LM2 murine breast cancer cell line. Relative quantification of target mRNA was performed with a TaqMan real-time RT-PCR assay. The CD4(+)CD25(high+) Treg cell numbers were significantly smaller in the tumor-bearing KO mice than in the wild type ones measured by flow-cytometry. The expression of forkhead box P3 (Foxp3) decreased significantly and the copies of splenic Tbox-21 (T-bet) transcriptional factor mRNA was higher in HDC KO tumor-bearing mice than those of normal mice. The cytokine levels showed that a smaller number of interleukin-13-producing Th2 cells were elicited compared to interferon-gamma-producing Th1 cells in the tumor-bearing HDC KO mice. In conclusion, the present study demonstrates that endogenous histamine stimulates the growth of breast adenocarcinoma tumor implants in mice by suppressing anti-tumor immunity.

Review article: immune suppression and colorectal cancer

BACKGROUND

Advances in immunology and molecular biology have shown that colorectal cancer is potentially immunogenic and that host immune responses influence survival. However, immune surveillance and activation is frequently ineffective in preventing and/or controlling tumour growth.

AIM

To discuss potential ways in which colorectal cancer induces immune suppression, its effect upon prognosis and avenues for therapeutic development.

METHOD

A literature review was undertaken for evidence of colorectal cancer-induced immune suppression using PubMed and Medline searches. Further studies were identified from the reference lists of identified papers.

RESULTS

Immune suppression occurs at a molecular and cellular level and can result in a shift from cellular to humoral immunity. Several mechanisms for immune suppression have been described affecting innate and adaptive immunity with suppression linked to poorer clinical outcome.

CONCLUSIONS

Colorectal cancer causes direct inhibition of the host's immune response with a detrimental effect upon prognosis. Immunotherapy offers a therapeutic strategy to counteract these effects with promising results seen particularly in precancerous conditions and early tumours. This review strongly suggests that immunotherapy should be incorporated into adjuvant therapeutic trials for stage 2 tumours and be considered as adjuvant treatment in conjunction with standard chemotherapy regimes for advanced disease.

The correlation between colorectal cancer rates of proliferation and apoptosis and systemic cytokine levels; plus their influence upon survival

Colorectal cancer development is associated with a shift in host immunity with suppression of the cell-mediated immune system (CMI) and a predominance of humoral immunity (HI). Tumour progression is also associated with increased rates of cell proliferation and apoptosis. The aim of this study was to investigate whether these factors correlate and have an influence upon prognosis. Long-term follow-up was performed on 40 patients with colorectal cancer who had levels of tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma and interleukin (IL)-10 measured from stimulated blood cultures before surgery. Their archived tumour specimens were analysed to determine a Ki-67-derived proliferation index (PI) and a M30-derived apoptosis index (AI). Tumour necrosis factor-alpha levels negatively correlated to tumour proliferation (rho=-0.697, P=0.01). Interleukin-10 levels had a positive correlation with tumour proliferation (rho=0.452, P=0.05) and apoptosis (rho=0.587, P=0.01). Patient survival correlates to tumour pathological stage (P=0.0038) and vascular invasion (P=0.0014). An AI< or =0.6% and TNF-alpha levels > or =8148 pg ml(-1) correlate to improved survival (P=0.032, P=0.021). Tumour proliferation and apoptosis correlate to progressive suppression of the CMI-associated cytokine TNF-alpha and to and higher levels of IL-10. Survival is dependent upon the histological stage of the tumour, vascular invasion, rates of apoptosis and proliferation and systemic immunity which are all interconnected.

Current concepts in neuroendocrine cancer metabolism

Neuroendocrine (NE) cancers occur in multiple anatomic locations and range in prognosis from indolent to aggressive. In addition, adenocarcinomas can express gene products associated with NE cells, referred to as NE differentiation (NED), which correlates with poor prognosis and aggressive disease. Several metabolites and peptides produced by NE cells have been discovered that engage in cellular signaling and have autocrine and paracrine effects on cancer cell proliferation. This review focuses on the current knowledge of small molecule metabolism in NE cancers involving the synthesis of biogenic amine, polyamine, and amino acid neurotransmitters. Systems biology-directed approaches to NE cancer metabolism using gene expression profiling, liquid chromatography/mass spectrometry (LC/MS) and nuclear magnetic resonance (NMR) are also discussed. Furthermore, knowledge of metabolic and signaling pathways in NE cancers has led to the successful implementation of therapeutic regimens in cell culture and animal models of NE carcinogenesis.

Histamine regulates growth of malignant melanoma implants via H2 receptors in mice

The present study examined the effect of histamine H2-receptor antagonists and exogenous histamine on growth of malignant melanoma implant in mice. Drugs were administered to B16BL6 malignant-melanoma-implanted syngeneic mice, and the tumor volume was measured throughout the experiments. Cell proliferation was assessed by MTT assay and mRNA expression was determined by RT-PCR. Both roxatidine and cimetidine significantly suppressed growth of B16BL6 implant compared with vehicle. On the other hand, systemically administered histamine significantly stimulated growth of B16BL6 implants. In addition, the histamine-stimulated B16BL6 implant growth was markedly suppressed by co-administration of cimetidine in a dose-dependent manner. H2-receptor antagonists, however, failed to affect in vitro proliferation of B16BL6 cells. H2-receptor mRNA was detected in B16BL6 implants but not in the cell line. These results indicated that both endogenous and exogenous histamine have ability to stimulate growth of malignant melanoma implants via H2 receptors expressed in host cells.