Regulation of colorectal cancer cell epithelial to mesenchymal transition by the renin angiotensin system

An angiotensin system inhibitor (losartan) potentiates antitumor efficacy of cisplatin in a murine model of non-small cell lung cancer

Objective

Previous studies have demonstrated synergistic antitumor effects of angiotensin system inhibition (ASI) combined with cisplatin therapy in pancreatic cancer. This study examines whether or not synergistic antitumor effects occur with combination ASI and cisplatin treatment in lung cancer, and whether or not ASI-induced changes in epithelial-mesenchymal transition play a role in the mechanism of this antitumor phenomenon.

Methods

A set of lung cancer cell lines representing a spectrum of epithelial to mesenchymal phenotypes were identified and characterized. Response of epithelial-mesenchymal transition markers to losartan was characterized. Cell culture models of lung cancer were next treated with losartan, cisplatin, or combination of both. Markers of epithelial-mesenchymal transition or surrogates of other signaling pathways (AKT, Stat3, and programmed death-ligand), and cell viability were quantified. Findings were confirmed in both allogenic and syngeneic in vivo murine flank tumor models.

Results

Losartan treatment significantly increased E-cadherin and reduced vimentin in human lung cancer cell lines. Combination treatment with losartan and cisplatin enhanced epithelial markers, reduced mesenchymal markers, inhibited promesenchymal signaling mediators, and reduced cell viability. Findings were confirmed in vivo in a murine flank tumor model with transition from mesenchymal to epithelial phenotype and reduced tumor size following combination losartan and cisplatin treatment.

Conclusions

Combination losartan and cisplatin treatment attenuates the epithelial-mesenchymal transition pathway and enhances the cytotoxic effect of chemotherapy with in vitro and in vivo models of non-small cell lung cancer. This study suggests an important role for ASI therapy in the treatment of lung cancer.

The Role of the Renin-Angiotensin System in the Cancer Stem Cell Niche

Cancer stem cells (CSCs) drive metastasis, treatment resistance, and tumor recurrence. CSCs reside within a niche, an anatomically distinct site within the tumor microenvironment (TME) that consists of malignant and non-malignant cells, including immune cells. The renin-angiotensin system (RAS), a critical regulator of stem cells and key developmental processes, plays a vital role in the TME. Non-malignant cells within the CSC niche and stem cell signaling pathways such as the Wnt, Hedgehog, and Notch pathways influence CSCs. Components of the RAS and cathepsins B and D that constitute bypass loops of the RAS are expressed on CSCs in many cancer types. There is extensive in vitro and in vivo evidence showing that RAS inhibition reduces tumor growth, cell proliferation, invasion, and metastasis. However, there is inconsistent epidemiological data on the effect of RAS inhibitors on cancer incidence and survival outcomes, attributed to different patient characteristics and methodologies used between studies. Further mechanistic studies are warranted to investigate the precise effects of the RAS on CSCs directly and/or the CSC niche. Targeting the RAS, its bypass loops, and convergent signaling pathways participating in the TME and other key stem cell pathways that regulate CSCs may be a novel approach to cancer treatment.

Roles of G Protein-Coupled Receptors (GPCRs) in Gastrointestinal Cancers: Focus on Sphingosine 1-Shosphate Receptors, Angiotensin II Receptors, and Estrogen-Related GPCRs

It is well established that gastrointestinal (GI) cancers are common and devastating diseases around the world. Despite the significant progress that has been made in the treatment of GI cancers, the mortality rates remain high, indicating a real need to explore the complex pathogenesis and develop more effective therapeutics for GI cancers. G protein-coupled receptors (GPCRs) are critical signaling molecules involved in various biological processes including cell growth, proliferation, and death, as well as immune responses and inflammation regulation. Substantial evidence has demonstrated crucial roles of GPCRs in the development of GI cancers, which provided an impetus for further research regarding the pathophysiological mechanisms and drug discovery of GI cancers. In this review, we mainly discuss the roles of sphingosine 1-phosphate receptors (S1PRs), angiotensin II receptors, estrogen-related GPCRs, and some other important GPCRs in the development of colorectal, gastric, and esophageal cancer, and explore the potential of GPCRs as therapeutic targets.

Captopril, a Renin-Angiotensin System Inhibitor, Attenuates Features of Tumor Invasion and Down-Regulates C-Myc Expression in a Mouse Model of Colorectal Cancer Liver Metastasis

Simple Summary

Approximately 25% of patients with colorectal cancer will present with or develop colorectal liver metastasis (CRLM). Surgical resection of CRLM offers these patients the best chance of a cure. However, liver resection and the subsequent regenerative response has been linked to tumor recurrence in the liver remnant. The Wnt/β-catenin pathway is one of many pathways common to both post-hepatectomy liver regeneration and tumorigenesis. Wnt signaling modulates multiple genes of the renin-angiotensin system (RAS), and Wnt inhibition can attenuate fibrotic responses and improve cancer outcomes via diverse mechanisms. In this study, we investigate the effects of captopril, a RAS inhibitor (RASi), on the Wnt/β-catenin pathway and phenotypic changes associated with tumor progression in the context of the regenerating liver. We show that RASi induced increased Wnt signaling whilst downregulating features of epithelial-to-mesenchymal transition (EMT). Furthermore, RASi induced significant down-regulation of Wnt target genes, c-myc and cyclin D1, indicating that expression of these genes can be down-regulated by RASi despite the accumulation of stabilized β-catenin.

Abstract

(1) Background: Recent clinical and experimental data suggests that the liver’s regenerative response following partial hepatectomy can stimulate tumor recurrence in the liver remnant. The Wnt/β-catenin pathway plays important roles in both colorectal cancer carcinogenesis and liver regeneration. Studies have shown that the Wnt/β-catenin pathway regulates multiple renin-angiotensin system (RAS) genes, whilst RAS inhibition (RASi) reduces tumor burden and progression. This study explores whether RASi attenuates features of tumor progression in the regenerating liver post-hepatectomy by modulating Wnt/β-catenin signaling. (2) Methods: Male CBA mice underwent CRLM induction, followed one week later by 70% partial hepatectomy. Mice were treated daily with captopril, a RASi, at 250 mg/kg/day or vehicle control from experimental Day 4. Tumor and liver samples were analyzed for RAS and Wnt signaling markers using qRT-PCR and immunohistochemistry. (3) Results: Treatment with captopril reduced the expression of down-stream Wnt target genes, including a significant reduction in both c-myc and cyclin-D1, despite activating Wnt signaling. This was a tumor-specific response that was not elicited in corresponding liver samples. (4) Conclusions: We report for the first time decreased c-myc expression in colorectal tumors following RASi treatment in vivo. Decreased c-myc expression was accompanied by an attenuated invasive phenotype, despite increased Wnt signaling.

Kopsanone inhibits proliferation and migration of invasive colon cancer cells

Colorectal cancer (CRC) is the second leading cause of cancer-related death globally. In spite of the increasing knowledge on molecular characteristics of different cancer types including CRC, there is limitation in the development of an effective treatment. The present study aimed to verify the antitumor effect of kopsanone, an indole alkaloid. To achieve this, we treated human colon cancer cells (Caco-2 and HCT-116) with kopsanone and analyzed its effects on cell viability, cell-cell adhesion, and actin cytoskeleton organization. In addition, functional assays including micronuclei formation, colony formation, cell migration, and invasiveness were performed. We observed that kopsanone reduced viability and proliferation and induced micronuclei formation of HCT-116 cells. Also, kopsanone inhibited anchorage-dependent colony formation and modulated adherens junctions (AJs), thus increasing the localization of E-cadherin and β-catenin in the cytosol of the invasive cells. Finally, fluorescence assays showed that kopsanone decreased stress fibers formation and reduced migration but not invasion of HCT-116 cells. Taken together, these findings indicate that kopsanone reduces proliferation and migration of HCT-116 cells via modulation of AJs and can therefore be considered for future in vivo and clinical investigation as potential therapeutic agent for treatment of CRC.

Angiotensin II and Angiotensin Receptors 1 and 2-Multifunctional System in Cells Biology, What Do We Know?

For years, the renin-angiotensin system (RAS) has been perceived as a system whose role is to primarily modulate the functioning of the cardiovascular system. Years of research into the role of RAS have provided the necessary data to confirm that the role of RAS is very complex and not limited to the cardiovascular system. The presence of individual elements of the renin-angiotensin (RA) system allows to control many processes, ranging from the memorization to pro-cancer processes. Maintaining the proportions between the individual axes of the RA system allows for achieving a balance, often called homeostasis. Thus, any disturbance in the expression or activity of individual RAS elements leads to pathophysiological processes.

Irbesartan inhibits metastasis by interrupting the adherence of tumor cell to endothelial cell induced by angiotensin II in hepatocellular carcinoma

Background

The use of angiotensin II inhibitors is associated with a low risk of recurrence and metastasis in hepatocellular carcinoma (HCC) patients. Vascular cell adhesion molecule-1 (VCAM-1) is a key factor in tumor metastasis.

Methods

The effects of angiotensin II and irbesartan (an angiotensin II inhibitor) on HCC were explored with a xenograft model, microarray analysis and cell adhesion experiments. The relationship between the expression of VCAM-1 in HCC tissues and prognosis was analyzed with public and our institutional clinical databases. The effects of angiotensin II, irbesartan and VCAM-1 on adhesion and metastasis in HCC were explored with a xenograft model and cell adhesion experiments. The regulatory mechanisms were analyzed by Western blot analysis.

Results

Angiotensin II type 1 receptor and VCAM-1 were expressed in HCC tissues. Irbesartan inhibited HCC growth and metastasis in vivo and weakened the adhesion of HCC cells to endothelial cells, an effect that was enhanced by angiotensin II. VCAM-1 was found to be an independent risk factor for recurrence and survival in HCC patients with microvascular invasion. Angiotensin II upregulated VCAM-1 expression, and this upregulation was inhibited by irbesartan. Angiotensin II enhanced adhesion mainly by promoting the expression of VCAM-1 in HCC cells. Irbesartan inhibited the expression of VCAM-1 by reducing p38/MAPK phosphorylation activated by angiotensin II in HCC cells.

Conclusions

Irbesartan attenuates metastasis by inhibiting angiotensin II-activated VCAM-1 via the p38/MAPK pathway in HCC.

Cancer Stem Cells in Metastatic Head and Neck Cutaneous Squamous Cell Carcinoma Express Components of the Renin-Angiotensin System

We investigated the expression of components of the renin-angiotensin system (RAS) by cancer stem cell (CSC) subpopulations in metastatic head and neck cutaneous squamous cell carcinoma (mHNcSCC). Immunohistochemical staining demonstrated expression of prorenin receptor (PRR), angiotensin-converting enzyme (ACE), and angiotensin II receptor 2 (AT₂R) in all cases and angiotensinogen in 14 cases; however, renin and ACE2 were not detected in any of the 20 mHNcSCC tissue samples. Western blotting showed protein expression of angiotensinogen in all six mHNcSCC tissue samples, but in none of the four mHNcSCC-derived primary cell lines, while PRR was detected in the four cell lines only. RT-qPCR confirmed transcripts of angiotensinogen, PRR, ACE, and angiotensin II receptor 1 (AT₁R), but not renin or AT₂R in all four mHNcSCC tissue samples and all four mHNcSCC-derived primary cell lines, while ACE2 was expressed in the tissue samples only. Double immunohistochemical staining on two of the mHNcSCC tissue samples showed expression of angiotensinogen by the SOX2+ CSCs within the tumor nests (TNs), and immunofluorescence showed expression of PRR and AT₂R by the SOX2+ CSCs within the TNs and the peritumoral stroma (PTS). ACE was expressed on the endothelium of the tumor microvessels within the PTS. We demonstrated expression of angiotensinogen by CSCs within the TNs, PRR, and AT₂R by the CSCs within the TNs and the PTS, in addition to ACE on the endothelium of tumor microvessels in mHNcSCC.

Renin-Angiotensin System in the Tumor Microenvironment

For enhancing the antitumor effects of current immunotherapies including immune-checkpoint blockade, it is important to reverse cancer-induced immunosuppression. The renin-angiotensin system (RAS) controls systemic body fluid circulation; however, the presence of a local RAS in tumors has been reported. Furthermore, the local RAS in tumors influences various immune and interstitial cells and affects tumor immune response. RAS stimulation through the angiotensin II type 1 receptor has been reported to inhibit tumor immune response. Therefore, RAS inhibitors and combined treatment with immunotherapy are expected in the future. In this chapter, we provide a background on the RAS and describe the tumor environment with regard to the RAS and tumor immune response.

Elucidating the Association Between the Upregulation of Angiotensin Type 1-Receptors and the Development of Gastrointestinal Malignancies

The renin-angiotensin system (RAS) is a major regulator of body fluid hemostasis and blood pressure. Angiotensin type 1 receptors (AT1R) are one of the major components of this system and are widely expressed in different organs, including the gastrointestinal (GI) system. Very little known about the physiological roles of AT1R in GI tract but evidence has reported that local AT1Rs are upregulated in pathological conditions like GI malignancies and play role in stimulation of signaling pathways associated with GI cancers progression. AT1Rs axes signaling in tumor microenvironments stimulate inflammation and facilitate vascularization around the tumor cell to display invasive behavior. AT1Rs in stroma cells promote tumor-associated angiogenesis by upregulated of vessel endothelial growth factor (VEGF). Also, AT1Rs by the activation of molecular mechanisms such as PI3/Akt/NF-κB pathways increase the invasion of tumor cells. Experimental and clinical studies have reported that AT1R antagonists have beneficial influences by increasing the survival of patients with GI malignancies and reduction in the proliferation of GI cancer cell lines in vitro, and the growth and metastasis of tumors in vivo, therefore, AT1Rs antagonist have the potential for future anticancer strategies. This review focuses on the pathological roles of AT1Rs in GI malignancies.

Impact of chemotherapeutic effects on the pathophysiology of the arterial wall - insights from peripheral arterial disease

Systemic antineoplastic treatment agents represent one of the fastest developing medical fields. Oncological treatment is becoming increasingly individualized and new targets with corresponding agents, are constantly being developed. In tandem with this progress, new combinations and algorithms have evolved and patient's outcome have improved. Expanding tumors rely on a growing neovascular network to maintain their increased metabolism, which is caused by an accelerated reproduction rate. Accordingly, interrupting this supply mechanism is a major component of antineoplastic pharmaceutics and is a hallmark of cancer treatment. With advances in cancer treatment, long-term side effects have become an important consideration, especially in cases of neoplasia in young patients. While neuropathy and cardiotoxicity are well documented, vascular adverse events remain poorly understood. The mutual risk factors, like smoking and increased age, complicate the association between the vascular pathology and the earlier antineoplastic therapy. A deeper understanding of the effects of chemotherapy on peripheral arterial disease could lead to more detailed pathophysiological insight into both maladies and to new treatment options.

The Neuropeptide System and Colorectal Cancer Liver Metastases: Mechanisms and Management

Colorectal cancer (CRC), classified as the third most prevalent cancer worldwide, remains to be a clinical and research challenge. It is estimated that ~50% of CRC patients die from distant metastases, with treatment of this complication still posing significant difficulties. While liver metastasis (LM) cascade is known in the literature, its mechanisms are still unclear and remain studied in different research models. A connection is suggested between nervous system dysfunctions and a range of Neurotransmitters (Nts) (including Neuropeptides, NPs), Neurotrophins (Ntt) and their receptors (Rs) in CRC liver metastasis development. Studies on the role of NP/NP-Rs in the progression and metastasis of CRC, show the complexity of brain–tumor interactions, caused by their different forms of release to the extracellular environment (endocrine, autocrine, paracrine and neurocrine). Many stages of LM are connected to the activity of pro-inflammatory, e.g., Corticotropin-releasing Hormone Receptor 1 (CRHR1), Neuropeptide Y (NPY) and Neurotensin (NT), anti-inflammatory, e.g., Calcitonin Gene-related Peptide (CGRP), CRHR2 and Vasoactive Intestinal Polypeptide (VIP) or dual role neuropeptides, e.g., Substance P (SP). The regulation of the local immunological profile (e.g., CRH/CRHRs), dysfunctions of enteroprotective role of NPs on epithelial cells (e.g., NT/NT-R), as well as structural-functional changes in enteric nervous system innervation of the tumor are also important. More research is needed to understand the exact mechanisms of communication between the neurons and tumor cells. The knowledge on the mechanisms regulating tumor growth and different stages of metastasis, as well as effects of the action of a numerous group of Nts/NPs/Ntt as growth factors, have implications for future therapeutic strategies. To obtain the best treatment outcomes, it is important to use signaling pathways common for many NPs, as well to develop a range of broad-spectrum antagonists. This review aims to summarize the current knowledge on the importance of neuroactive molecules in the promotion of the invasion-metastasis cascade in CRC, as well as the improvements of clinical management of CRC liver metastasis.

The Neuropeptide System and Colorectal Cancer Liver Metastases: Mechanisms and Management

Colorectal cancer (CRC), classified as the third most prevalent cancer worldwide, remains to be a clinical and research challenge. It is estimated that ~50% of CRC patients die from distant metastases, with treatment of this complication still posing significant difficulties. While liver metastasis (LM) cascade is known in the literature, its mechanisms are still unclear and remain studied in different research models. A connection is suggested between nervous system dysfunctions and a range of Neurotransmitters (Nts) (including Neuropeptides, NPs), Neurotrophins (Ntt) and their receptors (Rs) in CRC liver metastasis development. Studies on the role of NP/NP-Rs in the progression and metastasis of CRC, show the complexity of brain–tumor interactions, caused by their different forms of release to the extracellular environment (endocrine, autocrine, paracrine and neurocrine). Many stages of LM are connected to the activity of pro-inflammatory, e.g., Corticotropin-releasing Hormone Receptor 1 (CRHR1), Neuropeptide Y (NPY) and Neurotensin (NT), anti-inflammatory, e.g., Calcitonin Gene-related Peptide (CGRP), CRHR2 and Vasoactive Intestinal Polypeptide (VIP) or dual role neuropeptides, e.g., Substance P (SP). The regulation of the local immunological profile (e.g., CRH/CRHRs), dysfunctions of enteroprotective role of NPs on epithelial cells (e.g., NT/NT-R), as well as structural-functional changes in enteric nervous system innervation of the tumor are also important. More research is needed to understand the exact mechanisms of communication between the neurons and tumor cells. The knowledge on the mechanisms regulating tumor growth and different stages of metastasis, as well as effects of the action of a numerous group of Nts/NPs/Ntt as growth factors, have implications for future therapeutic strategies. To obtain the best treatment outcomes, it is important to use signaling pathways common for many NPs, as well to develop a range of broad-spectrum antagonists. This review aims to summarize the current knowledge on the importance of neuroactive molecules in the promotion of the invasion-metastasis cascade in CRC, as well as the improvements of clinical management of CRC liver metastasis.

Evaluating the benefits of renin-angiotensin system inhibitors as cancer treatments

G-protein-coupled receptors (GPCRs) are the largest and most diverse group of cellular membrane receptors identified and characterized. It is estimated that 30 to 50% of marketed drugs target these receptors. The angiotensin II receptor type 1 (AT1R) is a GPCR which signals in response to systemic alterations of the peptide hormone angiotensin II (AngII) in circulation. The enzyme responsible for converting AngI to AngII is the angiotensin-converting enzyme (ACE). Specific inhibitors for the AT1R (more commonly known as AT1R blockers or antagonists) and ACE are well characterized for their effects on the cardiovascular system. Combined with the extensive clinical data available on patient tolerance of AT1R blockers (ARBs) and ACE inhibitors (ACEIs), as well as their non-classical roles in cancer, the notion of repurposing this class of medications as cancer treatment(s) is explored in the current review. Given that AngII-dependent AT1R activity directly regulates angiogenesis, remodeling of vasculature, pro-inflammatory responses, stem cell programming and hematopoiesis, and electrolyte balance; the modulation of these processes with pharmacologically well characterized medications could present a valuable complementary treatment option for cancer patients.

The Therapeutic Potential of Angiotensin-converting Enzyme and Angiotensin Receptor Inhibitors in the Treatment of Colorectal Cancer: Rational Strategies and Recent Progress

Colorectal cancer (CRC) is one of the most common causes of cancer-related death in the world. There is a document that angiotensin (AT) which is found to be involved in the progression of CRC. Furthermore, Angiotensin receptor inhibitors (ARIs) and angiotensin-converting enzyme Inhibitors (ACE-Is) demonstrate activity in CRC by their inhibition of both Insulin-like growth factor 1 (IGF-1) and Vascular endothelial growth factor (VEGF), and therefore present a potentially novel therapeutic strategy in colorectal cancer, which have summarized in the current review. Preclinical studies have illustrated the direct effect of major active mediator angiotensin II (ATII) on the promotion of angiogenesis through VEGF and other proliferative mediators. Suppression of the angiotensin II type I receptor (AT1R) via ACE-Is has shown a reduction in the development of solid tumor and metastasis, particularly CRC incidence, polyp formation, and distant metastasis. MicroRNAs (miRs) are a family of small nucleotides without coding that plays an important role after transcribing hundreds to thousands of non-coding and coding gene. Against this background, the application of anti-hypertensive medications such as losartan might have a therapeutic impact, although further preclinical and clinical studies might provide novel insight into the potentially beneficial effect of ACE-Is in the treatment of colorectal cancer patients.

Therapeutic Targeting of Cancer Stem Cells in Human Glioblastoma by Manipulating the Renin-Angiotensin System

Patients with glioblastoma (GB), a highly aggressive brain tumor, have a median survival of 14.6 months following neurosurgical resection and adjuvant chemoradiotherapy. Quiescent GB cancer stem cells (CSCs) invariably cause local recurrence. These GB CSCs can be identified by embryonic stem cell markers, express components of the renin-angiotensin system (RAS) and are associated with circulating CSCs. Despite the presence of circulating CSCs, GB patients rarely develop distant metastasis outside the central nervous system. This paper reviews the current literature on GB growth inhibition in relation to CSCs, circulating CSCs, the RAS and the novel therapeutic approach by repurposing drugs that target the RAS to improve overall symptom-free survival and maintain quality of life.

Searching for the link; mechanisms underlying liver regeneration and recurrence of colorectal liver metastasis post partial hepatectomy

Despite excellent treatment of primary colorectal cancer, the majority of deaths occur as a result of metastasis to the liver. Recent population studies have estimated that one quarter of patients with colorectal cancer will incur synchronous or metachronous colorectal liver metastasis. However, only one quarter of these patients will be eligible for potentially curative resection. Tumor recurrence occurs in reportedly 60% of patients undergoing hepatic resection, and the majority of intrahepatic recurrence occurs within the first 6 months of surgery. The livers innate ability to restore its homeostatic size, and volume facilitates major hepatic resection that currently offers the only chance of cure to patients with extensive hepatic metastases. Experimental and clinical evidence supports the notion that following partial hepatectomy, liver regeneration (LR) paradoxically drives tumor progression and increases the risk of recurrence. It is becoming increasingly clear that the processes that drive liver organogenesis, regeneration, and tumor progression are inextricably linked. This presents a major hurdle in the management of colorectal liver metastasis and other hepatic malignancies because therapies that reduce the risk of recurrence without hampering LR are sought. The processes and pathways underlying these phenomena are multiple, complex, and cross-communicate. In this review, we will summarize the common mechanisms contributing to both LR and tumor recurrence.

Altered expression of renin-angiotensin system receptors throughout colorectal adenoma-adenocarcinoma sequence

Background and Objective: Colorectal cancer (CRC) is a major health problem in developed countries. Adenomatous lesions in the large bowel are the main precursors of CRC and the adenoma-adenocarcinoma sequence still provides a solid model for research on carcinogenesis. The finding of local renin-angiotensin systems (RAS) has been crucial to understand the role of this peptidergic system in cancer and has opened new perspectives in the study of colorectal carcinogenetic processes. Methods: In this study we analyzed the immunohistochemical expression of three main RAS receptors (AT1, AT2 and MAS) in a large series of CRC samples (n=161), including uninvolved intestinal mucosa-adenoma-adenocarcinoma sequences from the same patients (n=50). Results: 1) AT1 and AT2 showed a biphasic expression pattern along the sequence. The expression significantly decreased in adenomas with respect to uninvolved mucosa but increased in CRCs. 2) AT2 expression was lower in advanced CRCs with high local invasion (pT4), high stage (IV), high nodal (N2) and vascular invasion. 3) MAS receptor was moderately expressed in the uninvolved mucosa and in adenomas. This expression increased very significantly in CRC tissues. Conclusions: These results suggest that: 1) RAS receptors are differentially regulated as the genetic and epigenetic alterations accumulate throughout the uninvolved mucosa-adenoma-CRC sequence. 2) Loss of AT2 expression could contribute to the aggressive behavior of advanced CRC cells.

EXPRESSION OF THE RENIN-ANGIOTENSIN SYSTEM COMPONENTS IN ONCOLOGIC DISEASES

The literature devoted to changes in the expression of the renin-angiotensin system (RAS) proteins of cancer cells was analyzed. The dynamics of RAS protein expression in malignant tumors and the possible role of epigenetic mechanisms in these processes are briefly reviewed. Through research of the epigenetic mechanisms in cancer, principally new techniques for their correction based on the use of selective regulatory systems of covalent modification of histone proteins (for example, deacetylase inhibitor) and microRNA synthesis technologies have been developed. Literature data show promising pharmacological correction of epigenetic modification of chromatin in the treatment of cancer.

Cancer stem cells within moderately differentiated head and neck cutaneous squamous cell carcinoma express components of the renin-angiotensin system

PURPOSE

To investigate the expression of components of the renin-angiotensin system (RAS): pro-renin receptor (PRR), angiotensin converting enzyme (ACE), angiotensin II receptor 1 (ATIIR1) and angiotensin II receptor 2 (ATIIR2) by the cancer stem cell (CSC) subpopulations in moderately differentiated head and neck cutaneous squamous cell carcinoma (MDHNCSCC).

METHODOLOGY

3,3-Diaminobenzidine (DAB) immunohistochemical (IHC) staining for PRR, ACE, ATIIR1 and ATIIR2 was performed on formalin-fixed paraffin-embedded sections of ten MDHNCSCC tissue samples. Immunofluorescence (IF) IHC staining was used to localise components of the RAS. Western blotting (WB) and RT-qPCR were performed on snap-frozen MDHNCSCC tissue samples and MDHNCSCC-derived primary cell lines to investigate protein transcription expression of these proteins, respectively.

RESULTS

DAB IHC staining demonstrated the presence of PRR, ACE, ATIIR1 and ATIIR2 in all ten MDHNCSCC tissue samples. IF IHC staining showed expression of PRR and ATIIR2 by the OCT4⁺ cells, and ACE and ATIIR1 by the SOX2⁺ cells, within the tumour nests (TNs) and the peritumoural stroma (PTS). PRR, ACE, ATIIR1 and ATIIR2 were expressed by the endothelium of the microvessels within the PTS. WB confirmed protein expression for PRR, ACE and ATIIR1 in MDHNCSCC tissue samples and MDHNCSCC-derived primary cell lines. RT-qPCR showed transcriptional activation of PRR, ACE, ATIIR1 and ATIIR2 in MDHNCSCC tissue samples; and PRR, ACE, ATIIR1 but not ATIIR2, in MDHNCSCC-derived primary cell lines.

CONCLUSION

PRR, ACE, ATIIR1 and ATIIR2 are expressed by the CSC subpopulations within the TNs, the PTS, and the endothelium of the microvessels within the PTS, in MDHNCSCC.

Renin-angiotensin inhibitors reprogram tumor immune microenvironment: A comprehensive view of the influences on anti-tumor immunity

Renin-angiotensin system inhibitors (RASi) have shown potential anti-tumor effects that may have a significant impact in cancer therapy. The components of the renin-angiotensin system (RAS) including both, conventional and alternative axis, appear to have contradictory effects on tumor biology. The mechanisms by which RASi impair tumor growth extend beyond their function of modulating tumor vasculature. The major focus of this review is to analyze other mechanisms by which RASi reprogram the tumor immune microenvironment. These involve impairing hypoxia and acidosis within the tumor stroma, regulating inflammatory signaling pathways and oxidative stress, modulating the function of the non-cellular components and immune cells, and regulating the cross-talk between kalli krein kinin system and RAS.

Targeted Optical Imaging Agents in Cancer: Focus on Clinical Applications

Molecular imaging is an emerging strategy for in vivo visualization of cancer over time based on biological mechanisms of disease activity. Optical imaging methods offer a number of advantages for real-time cancer detection, particularly in the epithelium of hollow organs and ducts, by using a broad spectral range of light that spans from visible to near-infrared. Targeted ligands are being developed for improved molecular specificity. These platforms include small molecule, peptide, affibody, activatable probes, lectin, and antibody. Fluorescence labeling is used to provide high image contrast. This emerging methodology is clinically useful for early cancer detection by identifying and localizing suspicious lesions that may not otherwise be seen and serves as a guide for tissue biopsy and surgical resection. Visualizing molecular expression patterns may also be useful to determine the best choice of therapy and to monitor efficacy. A number of these imaging agents are overcoming key challenges for clinical translation and are being validated in vivo for a wide range of human cancers.

High Vimentin Expression Predicts a Poor Prognosis and Progression in Colorectal Cancer: A Study with Meta-Analysis and TCGA Database

The aim of this study was to evaluate the role of vimentin expression in the prognosis and progression of CRC. Meta-analysis was conducted to investigate the correlations between vimentin and prognosis and clinicopathological features in CRC. Literatures were searched by PubMed, Embase, ClinicalKey, CNKI, VIP, and WanFang databases. The Cancer Genome Atlas (TCGA) database was used to assess the association of vimentin expression with survival rate in CRC. Eleven reports with 1969 cases were included in the meta-analysis. The results showed that positive vimentin expression predicted a poor overall survival (OS) in the univariate analysis (HR: 2.087, 95%CI: 1.660-2.625) and multivariate analysis (HR: 1.633, 95%CI: 1.223-2.181). Vimentin overexpression also conferred worse disease-free survival (DFS) in the univariate analysis (HR: 2.069, 95%CI: 1.024-4.179) and multivariate analysis (HR: 2.802, 95%CI: 1.421-5.527). Moreover, upregulated vimentin is related to lymph node metastasis (OR: 2.288, 95%CI: 1.159-4.517), TNM stages (OR: 1.957, 95%CI: 1.333-2.873), and N stage (OR: 2.316, 95%CI: 1.482-3.620). Analysis of TCGA database indicated that elevated vimentin predicated a shorter OS (p=0.033). Our findings reveal that upregulated vimentin contributes to the progression and poor prognosis of CRC. Vimentin may be a prognostic biomarker and therapeutic target in patients with CRC.

Targeting the renin-angiotensin system to improve cancer treatment: Implications for immunotherapy

Renin-angiotensin system (RAS) inhibitors (RASi)-widely prescribed for the treatment of cardiovascular diseases-have considerable potential in oncology. The RAS plays a crucial role in cancer biology and affects tumor growth and dissemination directly and indirectly by remodeling the tumor microenvironment. We review clinical data on the benefit of RASi in primary and metastatic tumors and propose that, by activating immunostimulatory pathways, these inhibitors can enhance immunotherapy of cancer.

Support for involvement of the renin-angiotensin system in dysplastic Barrett's esophagus

BACKGROUND AND AIM

Patients with dysplasia in Barrett's esophagus (BE) have a considerable risk of developing esophageal adenocarcinoma (EAC). The mucosal expression of the pro-inflammatory angiotensin II receptor type 1 (AT1R) is elevated in these patients, suggesting a role in carcinogenesis. The purpose of this study was to determine whether interference with the renin-angiotensin system (RAS) would influence downstream markers of carcinogenesis.

METHODS

Endoscopic mucosal biopsies from BE patients with low-grade dysplasia (LGD) were sampled before and after a three-week period of RAS-interfering treatment. Thirty patients were randomly allocated to enalapril (ACE inhibitor, 5 mg od), candesartan (AT1R antagonist, 8 mg od), or no drug. The expression of 12 proteins known to be associated with RAS and carcinogenesis was assessed using western blot.

RESULTS

We found altered expression of several proteins after enalapril treatment (decreased: NFκB, p = .043; NLRP3, p = .050; AMACR, p = .017; and caspase 3, p = .025; increased: p53, p = .050). Candesartan treatment was associated with increased iNOS expression (p = .033). No significant changes were seen in the no-drug group.

CONCLUSION

Interference with angiotensin II formation was associated with altered expression of inflammation- and carcinogenesis-related proteins. The present results speak in favor of involvement of angiotensin II in BE dysplasia, but the role of AT1R should be investigated further.

Influence of KLF17 overexpression on epithelial-mesenchymal transition and invasion of SW480 colorectal cancer cells

AIM

To assess the impact of KLF17 overexpression on the epithelial-mesenchymal transition (EMT) and invasive ability of SW480 colorectal cancer cells.

METHODS

The recombinant KLF17 expression plasmid with EGFP was transfected into SW480 cells, and non-transfected SW480 cells and SW480 cells transfected with the empty vector were used as controls. The changes in KLF17 mRNA and protein expression were detected by real-time PCR and Western blot at 48 h after transfection with the recombinant KLF17 expression plasmid. The changes in the expression of epithelial and mesenchymal makers in SW480 cells were detected by real-time PCR and Western blot. Transwell chamber invasion assay was used to investigate the effect of KLF17 gene transfection on the invasive potential of SW480 cells.

RESULTS

The expression levels of KLF17 mRNA and protein in SW480 cells transfected with the recombinant plasmid (2.5087 ± 0.0288; 0.6100 ± 0.0579) were significantly increased compared with those in non-transfected SW480 cells (1.0000 ± 0.0198; 0.3543 ± 0.0340) (P < 0.01 for both). The expression levels of E-cadherin mRNA and protein in SW480 cells transfected with the recombinant plasmid (2.0704 ± 0.0620; 0.5446 ± 0.0245) were significantly higher than those in non-transfected SW480 cells (1.0000 ± 0.0106; 0.3952 ± 0.0430) (P < 0.01 for both), while the expression levels of vimentin mRNA and protein in SW480 cells transfected with the recombinant plasmid (0.4622 ± 0.0279; 0.3290 ± 0.0367) were significantly lower than those in non-transfected SW480 cells (1.0000 ± 0.0780; 0.5229 ± 0.0496) (P < 0.01 for both). After transfection with the recombination KLF17 expression plasmid, the invasive ability of SW480 cells (86.67 ± 10.97) was significantly lower than that of non-transfected SW480 cells (145.30 ± 11.37) and SW480 cells transfected with the empty vector (135.33 ± 12.66) (P < 0.01 for both).

CONCLUSION

KLF17 may inhibit SW480 cancer cell invasion by inhibiting EMT.

Systematic review of the old and new concepts in the epithelial-mesenchymal transition of colorectal cancer

Epithelial-to-mesenchymal transition (EMT) is defined as the transformation of an epithelial cell into a spindle cell with the loss of membrane E-cadherin expression and the gain of mesenchymal markers positivity. In the field of colorectal cancer (CRC), first data about EMT was published in 1995 and more than 400 papers had been written up to March 2016. Most of them are focused on the molecular pathways and experimentally-proved chemoresistance. In the present article, an update in the field of EMT in CRC based on the review of the literature and personal experience of the authors is presented. The information about the molecular and immunohistochemical (IHC) particularities of these processes and their possible role in the prognosis of CRC were also up-dated. This article focuses on the IHC quantification of the EMT, the immunoprofile of tumor buds and on the relation between EMT, angiogenesis, and stem cells activation. The EMT-induced chemoresistance vs chemotherapy- or radiotherapy-induced EMT and cellular senescence was also synthesized for both conventional and targeted therapy. As a future perspective, the EMT-angiogenesis-stemness link could be used as a possible valuable parameter for clinical follow-up and targeted therapeutic oncologic management of patients with CRC. Association of dexamethasone and angiotensin converting enzyme inhibitors combined with conventional chemotherapies could have clinical benefits in patients with CRC. The main conclusion is that, although many studies have been published, the EMT features are still incompletely elucidated and newly discovered EMT markers provide confusing data in understanding this complicated process, which might have significant clinical impact.