Appearance of angiotensin II expression in non-basal epithelial cells is an early feature of malignant change in human prostate

Association between ACE A240T polymorphism and cancer risk: a meta-analysis

Objectives

The relationship between the A240T polymorphism in the angiotensin-converting enzyme (ACE) gene and cancer risk remains controversial. Therefore, we conducted a meta-analysis of relevant studies from the published literature.

Methods

We comprehensively searched available databases to identify eligible studies on the relationship of ACE A240T polymorphism with cancer risk. We calculated pooled odds ratios (OR) with 95% confidence intervals (CI) and then evaluated heterogeneity and publication bias.

Results

Eight case-control studies were identified from five articles. Results showed that the ACE A240T polymorphism was related to cancer risk (AT vs AA: OR 2.14, 95% CI: 1.51–3.04; TT vs AA: OR 1.07, 95% CI: 0.90–1.27; recessive model: OR 0.48, 95% CI: 0.31–0.77; dominant model: OR 2.13, 95% CI: 1.54–2.97). The same conclusion was made for subgroup analysis by race or cancer type. In the subgroup analysis by quality score assessment, the ACE A240T polymorphism contributed to cancer risk in high-quality studies but not in low-quality studies.

Conclusion

The A240T polymorphism in the ACE gene might be related to the risk of cancer. Nevertheless, large-scale studies should be performed to obtain convincing evidence on the roles of ACE A240T polymorphism on cancer risk.

Role of Renin-Angiotensin-System in Human Breast Cancer Cells: Is There a Difference in Regulation of Angiogenesis between Hormone-Receptor Positive and Negative Breast Cancer Cells?

Objective This study examined the role of the RAS in human breast cancer cells to question if there are differences between HR-positive and HR-negative cells with regard to regulation of VEGF. Methods Expression of different RAS components in hormone receptor (HR)-positive and HR-negative breast cancer cells was investigated using RT-PCR. Different stimulation protocols with different RAS inhibitors were used to investigate the effect on VEGF expression. Angiotensin II-dependent expression of VEGF was quantified by real time PCR. In addition, the effect of intrinsic RAS was studied performing siRNA knockdown of angiotensinogen (AGT). Statistical analysis were calculated using IBM SPSS Statistics Version 21. Results Expression of AT ₁ R, AT ₂ R, AGT and ACE was shown in HR-positive and HR-negative breast cancer cell lines. Extrinsic stimulation with angiotensin II increased VEGF significantly. After treatment with captopril or AT ₁ R-inhibitor candesartan, VEGF-expression decreased significantly in HR-positive and HR-negative cell lines. However, inhibition of AT ₂ R using PD 123,319 did not show any significant changes of VEGF. After prevention of intrinsic angiotensin II, extrinsic angiotensin II as well as the combination with inhibitors of the receptors caused a significant reduction of VEGF. Surprisingly, the overall effect of the RAS after knockdown of AGT revealed a significant increase of VEGF in HR-positive cells at any time while a significant decrease was observed in HR-negative cells after 144 hours incubation. Conclusion The RAS-dependent regulation of VEGF between HR-positive and HR-negative breast cancer cells seems do be different. These findings provide evidence for a possible future therapeutic strategy.

Association of AGTR1 (A1166C) and ACE (I/D) Polymorphisms with Breast Cancer Risk in North Indian Population

Renin angiotensin system (RAS) comprising Angiotensin converting enzyme (ACE), Angiotensin II (Ang II) and its receptor Angiotensin II receptor type I (AGTR1), plays a critical role in several diseases including cancer. A single nucleotide polymorphism (SNP) A1166C located in 3' untranslated region (UTR) of AGTR1 and an insertion/deletion (I/D) polymorphism present in intron 16 of ACE gene have been associated with many diseases, but their association with Breast cancer (BCa) is still debatable. Here, we for the first time investigated the association of these polymorphisms in a North Indian BCa cohort including 161 patients and 152 healthy women. The polymorphisms were evaluated by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) respectively. The association between these polymorphisms and BCa risk was estimated by calculating Odds Ratio (OR) and chi-square (χ2) test. The DD genotype/D allele of ACE (I/D) polymorphism and "AC and CC" genotype/C allele of AGTR1 (A1166C) polymorphism were associated with higher risk of BCa when evaluated independently. Furthermore, interaction analysis of "AC and CC" and DD genotype and combination of "C and D" alleles of both polymorphisms revealed significantly greater BCa risk than that observed independently. Conclusively, women harboring "AC or CC" genotype/C allele for AGTR1 (A1166C) polymorphism and DD genotype/D allele for ACE (I/D) polymorphisms have a predisposition to develop more aggressive disease with advanced staging and larger tumor size. Our study indicates importance of genetic screening based on these polymorphisms for women, who may have higher risk of BCa.

Interaction between angiotensin II and relaxin 2 in the progress of growth and spread of prostate cancer cells

Deregulation of locally secreted hormones, such as angiotensin II (Ang II) and relaxin 2 (RLN2), has been linked to a higher risk of select cancers or a poor prognosis in patients. In this study, for the first time a common effect of Ang II and RLN2 in relation to various aspects of prostate cancer development and metastasis are presented. Four independent colorimetric assays were used to analyze cell viability and proliferation. The changes of cell adhesion to extracellular matrix proteins and invasion/aggressiveness ability of prostate cancer cells (LNCaP, PC3) before and after peptides treatment, were also investigated. The findings suggest that the both investigated systems, have an impact on cell growth/division or spread, to some degree via overlapping signal transduction pathways. Intermediate or sometimes poorer results were achieved by using a combination of both hormones than when each was used individually. It seems that Ang II and RLN2 can play a significant role in increasing the aggressiveness of prostate tumors by up-regulating BIRC5 expression and MMP-2 and MMP-9 secretion. In addition, we speculate that Ang II and RLN2 are involved in the transition from the androgen-dependent to the androgen-independent phenotype via modulation of the expression of androgen receptors.

The roles of beta-adrenergic receptors in tumorigenesis and the possible use of beta-adrenergic blockers for cancer treatment: possible genetic and cell-signaling mechanisms

Cancer is the leading cause of death in the USA, and the incidence of cancer increases dramatically with age. Beta-adrenergic blockers appear to have a beneficial clinical effect in cancer patients. In this paper, we review the evidence of an association between β-adrenergic blockade and cancer. Genetic studies have provided the opportunity to determine which proteins link β-adrenergic blockade to cancer pathology. In particular, this link involves the major histocompatibility complex class II molecules, the renin-angiotensin system, transcription factor nuclear factor-kappa-light-chain-enhancer of activated B cells, poly(ADP-ribose) polymerase-1, vascular endothelial growth factor, and the reduced form of nicotinamide adenine dinucleotide phosphate oxidase. Beta-adrenergic blockers also exert anticancer effects through non-genomic factors, including matrix metalloproteinase, mitogen-activated protein kinase pathways, prostaglandins, cyclooxygenase-2, oxidative stress, and nitric oxide synthase. In conclusion, β-adrenergic blockade may play a beneficial role in cancer treatment. Additional investigations that examine β-adrenergic blockers as cancer therapeutics are required to further elucidate this role.

Similarities and differences between effects of angiotensin III and angiotensin II on human prostate cancer cell migration and proliferation

Proliferation plays a critical role in tumor growth when cell migration is essential to invasion. The effect of Ang III and Ang II was evaluated on these important processes. Changes in the migration potential of prostate cancer cells were investigated using Wound Healing Test and a Transwell Migration Chamber with a 3 μm pore size. Cell proliferation was measured with a BrdU Assay and Countess Automated Cell Counter, thus determining the influence of angiotensins on hormone-dependent (LNCaP) and hormone-independent (DU-145) human prostate cancer lines. The influence of Ang III and Ang II on classic receptors may be inhibited by Losartan or PD123319. Test peptide modulation of the AT1 and AT2 receptors was examined by Western Blot and fluorescent immunocytochemistry. The results indicate that Ang III promotes the migration of both LNCaP and DU-145 lines, whereas Ang II stimulates this process only in androgen-independent cells. Both angiotensin peptides can induce prostate cancer cell proliferation in a time- and dose-dependent manner. The obtained results show that Ang III and Ang II can modify the expression of classic receptors, particularly AT2. These results suggest that the investigated peptide can modulate cell migration and proliferation in prostate cancer cells. Angiotensins probably have a greater influence on proliferation in the early-stage prostate cancer model than hormone-independent cell lines. Assume also that Ang II can enhance the migration tendency aggressive prostate cancer cells, while Ang III does so more effective in non-metastatic cells.

Expression of Angiotensin Ⅱand AT1R in colorectal cancer

AIM: To investigate the expression of Angiotensin Ⅱand AT₁R in colorectal cancer.

METHODS: Fresh colonic specimens were obtained from 6 healthy volunteers and 24 patients suffering from colorectal cancer (including 6 patients with poorly differentiated adenocarcinoma, 9 patients with moderately differentiated adenocarcinoma and 9 patients with well differentiated adenocarcinoma) by endoscopic punch biopsy. The diagnosis was confirmed pathologically. Immunohistochemistry was used to examine the expression of Angiotensin Ⅱ and AT₁R in the colon of patients with colorectal cancer and healthy volunteers.

RESULTS: The expression of Angiotensin Ⅱ and AT₁R proteins in the colon of patients with colorectal cancer with different differentiation grades was significantly higher than that in normal controls (21.24 ± 4.60, 19.90 ± 5.16, 17.87 ± 5.30 vs 2.45 ± 0.83; 15.98 ± 3.66, 8.13 ± 2.49, 8.12 ± 2.13 vs 2.53 ± 0.82, all P < 0.01). The expression of Angiotensin II had no difference among colorectal cancer with different differentiation grades (P > 0.05). Compared to moderately and well differentiated adenocarcinoma, the expression of AT₁R was higher in poorly differentiated grade (both P < 0.01).

CONCLUSION: These data suggest that Angiotensin Ⅱ and AT₁R perhaps play an important role in the pathogenesis of colorectal cancer.

A comparison of the effects of Angiotensin IV on androgen-dependent and androgen-independent prostate cancer cell lines

INTRODUCTION

Angiotensin IV is one of the biologically active peptides of the renin-angiotensin system. Limited data suggests that this hexapeptide could contribute to cancer development and/or progression.

MATERIALS AND METHODS

Using the MTT reduction assay as an indicator of cell viability, and the bromodeoxyuridine incorporation assay as an indicator of cell proliferation, the influence of Angiotensin IV was evaluated on two human prostate cancer lines: androgen-dependent (LNCaP) and androgen-independent (DU-145). The potential effect of Angiotensin IV classic angiotensin receptors was examined by using the selective antagonists losartan and PD123319. Finally, the changes in expression levels of AT1 and AT2 receptors were compared, before and after angiotensin treatment.

RESULTS

Angiotensin IV caused significant changes in cell viability and proliferation in LNCaP cells but not in DU-145. It was found that AT2 receptor blocker (PD123319) was able to diminish the suppressor effect of Angiotensin IV on bromodeoxyuridine incorporation into the DNA of androgen-dependent prostate cancer cells. Simultaneously, it was reported that Angiotensin IV is the factor that modulates the density of AT1 and AT2 receptors in prostate cancer cells.

CONCLUSIONS

These findings suggested that Angiotensin IV can modulate tumour cell proliferation in the early stage of androgen-dependent prostate cancer. The effect might be promoted by the change of the angiotensin receptor level.

The Expression of MTUS1/ATIP and Its Major Isoforms, ATIP1 and ATIP3, in Human Prostate Cancer

Angiotensin II (Ang II), the main effector of the renin angiotensin system, acts upon two distinct transmembrane receptors, the Ang II type 1 and the type 2 (AT₂-) receptor, to induce promotion and inhibition of ERK2 phosphorylation. The AT₂-receptor, through an interaction with its putative signaling partner MTUS1/ATIP (AT₂-receptor interacting protein), inhibits the mitogenic effects of EGF in prostate cancer cell lines representing both early and late stage disease. This is the first report on the expression of ATIP in normal and malignant human prostatic biopsies. The expression of ATIP and its major isoforms, ATIP1 and ATIP3, in normal prostatic cells and three prostate cancer cell lines was examined using QPCR and immunohistochemistry. Human biopsies containing benign prostatic hyperplasia (BPH), high grade prostatic intraepithelial neoplasia (HGPIN) and well, moderately and poorly differentiated prostate cancer were also examined. Overall, ATIP1 and ATIP3 mRNA expression was increased in malignant compared to normal tissues and cell lines. ATIP immunostaining was low or absent in both the basal and columnar epithelial cell layers surrounding BPH acini; however, it was observed in high concentration in neoplastic epithelial cells of HGPIN and was clearly evident in cytoplasms of malignant cells in all prostate cancer grades. ATIP immunostaining was also identified in the cytoplasms of LNCaP and PC3 prostate cancer cells. As the AT₂-receptor/ATIP inhibitory signaling pathway exists in malignant cells in all grades of prostate cancer, enhancement of this pathway may be a therapeutic target even after the development of androgen-independence.

The renin-angiotensin system and cancer: old dog, new tricks

For cancers to develop, sustain and spread, the appropriation of key homeostatic physiological systems that influence cell growth, migration and death, as well as inflammation and the expansion of vascular networks are required. There is accumulating molecular and in vivo evidence to indicate that the expression and actions of the renin-angiotensin system (RAS) influence malignancy and also predict that RAS inhibitors, which are currently used to treat hypertension and cardiovascular disease, might augment cancer therapies. To appreciate this potential hegemony of the RAS in cancer, an expanded comprehension of the cellular actions of this system is needed, as well as a greater focus on translational and in vivo research.

Expression and function of ATIP/MTUS1 in human prostate cancer cell lines

BACKGROUND

We have previously demonstrated Ang II type 2 (AT(2)-) receptor-mediated inhibition of EGF-induced prostate cancer cell growth in androgen-dependent (LNCaP) and independent (PC3) prostate cancer cell lines.

METHODS

To explore the signaling pathways involved in this inhibitory effect, we examined the interaction of the AT(2)-receptor with its novel regulatory partner ATIP using real time PCR, over-expression, siRNA and [(3)H]thymidine incorporation assays.

RESULTS

The results in human prostate cancer cell lines demonstrate the presence of ATIP in both cell lines examined, and suggest that (i) the AT(2)-receptor through an interaction with ATIP mediates an anti-growth factor effect in both androgen-dependent and androgen-independent cell lines; (ii) ATIP expression decreases as the rate of cell growth and androgen-independence increase; and (iii) EGF may act on cell growth in part by reducing the content of ATIP present in the cells.

CONCLUSIONS

The results support our earlier proposal in normal cell lines that ATIP is an important component of the cellular response to AT(2)-receptor activation. The results further suggest that a critical level of ATIP is required to mediate the effect of AT(2)-receptor activation to inhibit EGF mediated increases in cell growth. They also suggest that EGF may in part induce cell growth by suppressing the level of ATIP expression.

Peptide hormone regulation of angiogenesis

It is now apparent that regulation of blood vessel growth contributes to the classical actions of hormones on development, growth, and reproduction. Endothelial cells are ideally positioned to respond to hormones, which act in concert with locally produced chemical mediators to regulate their growth, motility, function, and survival. Hormones affect angiogenesis either directly through actions on endothelial cells or indirectly by regulating proangiogenic factors like vascular endothelial growth factor. Importantly, the local microenvironment of endothelial cells can determine the outcome of hormone action on angiogenesis. Members of the growth hormone/prolactin/placental lactogen, the renin-angiotensin, and the kallikrein-kinin systems that exert stimulatory effects on angiogenesis can acquire antiangiogenic properties after undergoing proteolytic cleavage. In view of the opposing effects of hormonal fragments and precursor molecules, the regulation of the proteases responsible for specific protein cleavage represents an efficient mechanism for balancing angiogenesis. This review presents an overview of the actions on angiogenesis of the above-mentioned peptide hormonal families and addresses how specific proteolysis alters the final outcome of these actions in the context of health and disease.

Role of the renin-angiotensin system in prostate cancer

Prostate cancer is highly prevalent in Western society, and its early stages can be controlled by androgen ablation therapy. However, the cancer eventually regresses to an androgen-independent state for which there is no effective treatment. The renin-angiotensin system (RAS), in particular the octapeptide angiotensin II, is now recognised to have important effects on growth factor signalling and cell growth in addition to its well known actions on blood pressure, fluid homeostasis and electrolyte balance. All components of the RAS have been recently identified in the prostate, consistent with the expression of a local RAS system in this tissue. This review focuses on the role of the RAS in the prostate, and the possibility that this pathway may be a potential therapeutic target for the treatment of prostate cancer and other prostatic diseases.

The renin-angiotensin system and malignancy

The renin-angiotensin system (RAS) is usually associated with its systemic action on cardiovascular homoeostasis. However, recent studies suggest that at a local tissue level, the RAS influences tumour growth. The potential of the RAS as a target for cancer treatment and the suggested underlying mechanisms of its paracrine effects are reviewed here. These include modulation of angiogenesis, cellular proliferation, immune responses and extracellular matrix formation. Knowledge of the RAS has increased dramatically in recent years with the discovery of new enzymes, peptides and feedback mechanisms. The local RAS appears to influence tumour growth and metastases and there is evidence of tissue- and tumour-specific differences. Recent experimental studies provide strong evidence that drugs that inhibit the RAS have the potential to reduce cancer risk or retard tumour growth and metastases. Manipulation of the RAS may, therefore, provide a safe and inexpensive anticancer strategy.

Functional angiotensin II type 2 receptors inhibit growth factor signaling in LNCaP and PC3 prostate cancer cell lines

BACKGROUND

There is clear evidence of a tissue-based renin-angiotensin system in the prostate and studies to date suggest that AT(1)-receptor blocking drugs inhibit the growth of some prostate cancer cell lines and delay the development of prostate cancer. The present studies examine the action of Ang II in two prostate cancer cell lines and report the presence of functional AT(2)-receptors that regulate the actions of growth factors.

METHODS

Immunohistochemistry was used to identify the presence of Ang II and QPCR techniques to examine AT(1)- and AT(2)-receptor mRNA expression in androgen-dependent (LNCaP) and independent (PC3) cell lines. The effects of AT(1)- and AT(2)-receptor activation upon EGF-induced DNA synthesis and ERK2 phosphorylation in these cells were also examined.

RESULTS

Functional AT(2)-receptors together with Ang II were identified in both cell lines and stimulation of these receptors inhibited EGF-induced DNA synthesis and ERK2 phosphorylation. AT(1)-receptors, although present in both cell lines, were only functional in LNCaP cells where activation stimulated DNA synthesis.

CONCLUSIONS

Functional AT(2)-receptors are present and have the capacity to inhibit EGF-induced prostate cancer cell growth in LNCaP and fast growing androgen-independent PC3 cell lines, whereas functional AT(1)-receptors are found only in LNCaP cells where their activation stimulates DNA synthesis.