Angiotensin Converting Enzyme Regulates Cell Proliferation and Migration

Losartan as an ACE inhibitor: a description of the mechanism of action through quantum biochemistry

Losartan (LST) is a potent and selective angiotensin II (Ang II) type 1 (AT1) receptor antagonist widely used in the treatment of hypertension. The formation of Ang II is catalyzed by the angiotensin I-converting enzyme (ACE) through proteolytic cleavage of angiotensin I (Ang I), which is involved in the control of blood pressure. Despite the vast literature on the relationship of losartan with the renin-angiotensin system (RAS), the actions of losartan on the sACE enzyme are so far poorly understood. In view of this, we investigated how losartan can interact with the sACE enzyme to block its activity and intracellular signaling. After performing docking assays following quantum biochemistry calculations using losartan and sACE crystallographic data, we report that their interaction results reveal a new mechanism of action with important implications for understanding its effects on hypertension.

Dynamic Covalent Hydrogels: Strong yet Dynamic

Hydrogels are crosslinked polymer networks with time-dependent mechanical response. The overall mechanical properties are correlated with the dynamics of the crosslinks. Generally, hydrogels crosslinked by permanent chemical crosslinks are strong but static, while hydrogels crosslinked by physical interactions are weak but dynamic. It is highly desirable to create synthetic hydrogels that possess strong mechanical stability yet remain dynamic for various applications, such as drug delivery cargos, tissue engineering scaffolds, and shape-memory materials. Recently, with the introduction of dynamic covalent chemistry, the seemingly conflicting mechanical properties, i.e., stability and dynamics, have been successfully combined in the same hydrogels. Dynamic covalent bonds are mechanically stable yet still capable of exchanging, dissociating, or switching in response to external stimuli, empowering the hydrogels with self-healing properties, injectability and suitability for postprocessing and additive manufacturing. Here in this review, we first summarize the common dynamic covalent bonds used in hydrogel networks based on various chemical reaction mechanisms and the mechanical strength of these bonds at the single molecule level. Next, we discuss how dynamic covalent chemistry makes hydrogel materials more dynamic from the materials perspective. Furthermore, we highlight the challenges and future perspectives of dynamic covalent hydrogels.

CK2 and the Hallmarks of Cancer

Cancer is a leading cause of death worldwide. Casein kinase 2 (CK2) is commonly dysregulated in cancer, impacting diverse molecular pathways. CK2 is a highly conserved serine/threonine kinase, constitutively active and ubiquitously expressed in eukaryotes. With over 500 known substrates and being estimated to be responsible for up to 10% of the human phosphoproteome, it is of significant importance. A broad spectrum of diverse types of cancer cells has been already shown to rely on disturbed CK2 levels for their survival. The hallmarks of cancer provide a rationale for understanding cancer's common traits. They constitute the maintenance of proliferative signaling, evasion of growth suppressors, resisting cell death, enabling of replicative immortality, induction of angiogenesis, the activation of invasion and metastasis, as well as avoidance of immune destruction and dysregulation of cellular energetics. In this work, we have compiled evidence from the literature suggesting that CK2 modulates all hallmarks of cancer, thereby promoting oncogenesis and operating as a cancer driver by creating a cellular environment favorable to neoplasia.

Akkermansia muciniphila induces mitochondrial calcium overload and α -synuclein aggregation in an enteroendocrine cell line

The gut microbiota influence neurodevelopment, modulate behavior, and contribute to neurodegenerative disorders. Several studies have consistently reported a greater abundance of Akkermansia muciniphila in Parkinson disease (PD) fecal samples. Therefore, we investigated whether A.muciniphila-conditioned medium (CM) could initiate α-synuclein (αSyn) misfolding in enteroendocrine cells (EEC) — a component of the gut epithelium featuring neuron-like properties. We found that A. muciniphila CM composition is influenced by the ability of the strain to degrade mucin. Our in vitro experiments showed that the protein-enriched fraction of mucin-free CM induces RyR-mediated Ca²⁺ release and increased mitochondrial Ca²⁺ uptake leading to ROS generation and αSyn aggregation. Oral administration of A. muciniphila cultivated in the absence of mucin to mice led to αSyn aggregation in cholecystokinin (CCK)-positive EECs but no motor deficits were observed. Noteworthy, buffering mitochondrial Ca²⁺ reverted the damaging effects observed. These molecular insights offer evidence that bacterial proteins can induce αSyn aggregation in EECs.

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Gut bacterium Akkermansia muciniphila is increased in patients with Parkinson disease

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A. muciniphila-conditioned medium induces mitochondrial Ca²⁺ overload in EECs

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Mitochondrial Ca²⁺ overload leads to ROS generation and αSyn aggregation in vitro

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Buffering mitochondrial Ca²⁺ inhibits A. muciniphila-induced αSyn aggregation

Bradykinin-Potentiating Peptide-Paclitaxel Conjugate Directed at Ectopically Expressed Angiotensin-Converting Enzyme in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer with poor prognosis. Here, we present a peptide-drug conjugate (PDC)-bradykinin-potentiating peptide-paclitaxel (BPP-PTX) conjugate-synthesized by conjugating BPP9a with PTX via a succinyl linker. BPP-PTX targets the angiotensin-converting enzyme (ACE) on TNBC cells. ACE was found to be ectopically expressed in two TNBC cell lines but was absent in both the receptor-positive breast cancer cell line and healthy kidney cell line. Overexpression, knockdown, and competitive inhibition experiments demonstrated ACE-mediated cytotoxicity of BPP-PTX. In vivo, ACE-positive tumors were enriched with BPP-PTX, with the PDC being better tolerated than plain PTX. Compared with plain PTX, BPP-PTX exhibited improved tumor-suppressive effects in MDA-MB-468 xenografted female nude mice. Meanwhile, BPP-PTX resulted in less body weight loss and white blood cell reduction toxicity. These results collectively imply the novelty, efficacy, and low-toxicity profile of BPP-PTX as a potential therapeutic for ACE-positive TNBC.

Cocoa (Theobroma cacao L.) Seed-Derived Peptides Reduce Blood Pressure by Interacting with the Catalytic Site of the Angiotensin-Converting Enzyme

This study aimed at determining the effect of cocoa proteins (CP) on the blood pressure, using in silico, in vitro and in vivo approaches. The in silico assay showed 26 Criollo cocoa peptides with alignment in the Blast^® analysis. Peptide sequences ranged from 6 to 16 amino acids, with molecular weight ranging from 560.31 to 1548.76 Da. The peptide sequences LSPGGAAV, TSVSGAGGPGAGR, and TLGNPAAAGPF showed the highest theoretical affinity with −8.6, −5.0, and −10.2 kcal/mol, for the angiotensin-converting enzyme (ACE), renin, and angiotensin II type 1 receptor (AT₁-R), respectively. The Criollo CP hydrolysates (CPH) presented in vitro ACE inhibitory activity with an IC₅₀ value of 0.49 mg/mL. Furthermore, the orogastric administration of 150 mg CP/kg/day in rats fed a high-fat (HF) diet (HF + CP group) showed a significant decrease in systolic blood pressure (SBP) by 5% (p < 0.001) and diastolic blood pressure (DBP) by 7% (p < 0.001) compared with the HF group. The human equivalent dose (HED) of CP for an adult (60 kg) is 1.45 g per day. These results suggest that the consumption of CP could reduce blood pressure by blocking ACE, and could be used as an ingredient in the elaboration of antihypertensive functional foods.

Alkaloid and acetogenin-rich fraction from Annona crassiflora fruit peel inhibits proliferation and migration of human liver cancer HepG2 cells

Plant species from Annonaceae are commonly used in traditional medicine to treat various cancer types. This study aimed to investigate the antiproliferative potential of an alkaloid and acetogenin-rich fraction from the fruit peel of Annona crassiflora in HepG2 cells. A liquid-liquid fractionation was carried out on the ethanol extract of A. crassiflora fruit peel in order to obtain an alkaloid and acetogenin-rich fraction (AF-Ac). Cytotoxicity, proliferation and migration were evaluated in the HepG2 cells, as well as the proliferating cell nuclear antigen (PCNA), vinculin and epidermal growth factor receptor (EGFR) expression. In addition, intracellular Ca2+ was determined using Fluo4-AM and fluorescence microscopy. First, 9 aporphine alkaloids and 4 acetogenins that had not yet been identified in the fruit peel of A. crassiflora were found in AF-Ac. The treatment with 50 μg/mL AF-Ac reduced HepG2 cell viability, proliferation and migration (p < 0.001), which is in accordance with the reduced expression of PCNA and EGFR levels (p < 0.05). Furthermore, AF-Ac increased intracellular Ca2+ in the HepG2 cells, mobilizing intracellular calcium stores, which might be involved in the anti-migration and anti-proliferation capacities of AF-Ac. Our results support the growth-inhibitory potential of AF-Ac on HepG2 cells and suggest that this effect is triggered, at least in part, by PCNA and EGFR modulation and mobilization of intracellular Ca2+. This study showed biological activities not yet described for A. crassiflora fruit peel, which provide new possibilities for further in vivo studies to assess the antitumoral potential of A. crassiflora, especially its fruit peel.

The sodium/D-dimer ratio predicts the effect of first-line chemotherapy and prognosis in patients with advanced gastric cancer

BACKGROUND

Gastric cancer (GC) is one of the most common cancers worldwide. The survival time of patients with advanced gastric cancer (AGC) is shortened. We evaluated the role of the sodium/fibrinogen ratio (SFR) and sodium/D-dimer ratio (SDR) in predicting the first-line chemotherapy response, progression-free survival (PFS), and overall survival (OS) of patients with AGC.

METHODS

A total of 304 patients with AGC were retrospectively reviewed. SDR only was selected as a potential prognostic marker for the subsequent studies in this study. Based on the cut-off value of the SDR, the patients were divided into high-SDR and low-SDR groups and investigated for their clinicopathological features, first-line chemotherapy effects and clinical outcomes.

RESULTS

The cut-off value based on the SDR was 282.22, and the patients were divided into low-SDR (SDR ≤ 282.22) and high-SDR (SDR > 282.22) groups. The disease control rate was higher in the high-SDR group than in the low-SDR group (91.1% vs. 82.3%; P = 0.036). Patients with a high SDR had a longer median PFS and OS than those with a low SDR (PFS: 206.0 vs. 134.0 days, P < 0.001; OS: 435.0 vs. 295.5 days, P < 0.001). The SDR was an independent prognostic indicator in the multivariable analysis of PFS (P < 0.001) and OS (P = 0.004). In subgroup analyses, among the patients with normal sodium and D-dimer levels, SDR was still a reliable prognostic indicator of PFS and OS in patients with AGC (all P ≤ 0.001).

CONCLUSIONS

This study suggests that the SDR may serve as a prognostic indicator for chemotherapy outcome, PFS and OS for patients with AGC receiving first-line chemotherapy.

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.

New tricks of old drugs: Repurposing non-chemo drugs and dietary phytochemicals as adjuvants in anti-tumor therapies

Combination therapy has long been applied to enhance therapeutic effect and deal with the occurrence of multi-drug resistance in cancer treatment. However, the overlapping toxicity of multiple anticancer drugs to healthy tissues and increasing financial burden on patients emerged as major concerns. As promising alternatives to chemo agents, repurposed non-chemo drugs and dietary phytochemicals have been investigated as adjuvants to conventional anti-tumor therapeutics, offering a safe and economic strategy for combination therapy. In this review, we aim to highlight the advances in research about combination therapy using conventional therapeutics and repurposed drugs or phytochemicals for an enhanced anti-tumor efficacy, along with the mechanisms involved in the synergism. Beyond these, we outlined the potential challenges and solutions for clinical translation of the proposed combination therapy, providing a safe and affordable strategy to improve the reach of cancer therapy to low income regions with such new tricks of old drugs.

In Silico Analysis and In Vitro Characterization of the Bioactive Profile of Three Novel Peptides Identified from 19 kDa α-Zein Sequences of Maize

In this study, we characterized three novel peptides derived from the 19 kDa α-zein, and determined their bioactive profile in vitro and developed a structural model in silico. The peptides, 19ZP1, 19ZP2 and 19ZP3, formed α-helical structures and had positive and negative electrostatic potential surfaces (range of -1 to +1). According to the in silico algorithms, the peptides displayed low probabilities for cytotoxicity (≤0.05%), cell penetration (10-33%) and antioxidant activities (9-12.5%). Instead, they displayed a 40% probability for angiotensin-converting enzyme (ACE) inhibitory activity. For in vitro characterization, peptides were synthesized by solid phase synthesis and tested accordingly. We assumed α-helical structures for 19ZP1 and 19ZP2 under hydrophobic conditions. The peptides displayed antioxidant activity and ACE-inhibitory activity, with 19ZP1 being the most active. Our results highlight that the 19 kDa α-zein sequences could be explored as a source of bioactive peptides, and indicate that in silico approaches are useful to predict peptide bioactivities, but more structural analysis is necessary to obtain more accurate data.

Renin-angiotensin System Inhibitors and Development of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

Background:

There are controversial results available about using angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) and the development of cancers or improvement of clinical outcomes. Studies reported that using ACEI/ARB may enhance the development of hepatocellular carcinoma (HCC) and clinical outcomes.

Objective:

This meta-analysis aimed to assess the relationship between ACEI/ARB therapy and the development of HCC.

Methods:

PubMed, EMBASE and the Cochrane library were reviewed to identify clinical studies investigating the association between ACEI/ARB therapy and the risk of HCC development. The pooled risk ratio (RR) with 95% confidence intervals collected for the association between using ACEIs/ARBs and HCC development.

Results:

Patients with HCC benefit from the treatment with both ACEIs and ARBs (RR 0.704, 95% CI 0.526- 0.944, p = 0.019). However, only using ARBs was related to HCC risk (0.545 95% CI 0.470-0.632, P<0.0001). Moreover, the study types were significantly related to the observed effects of using both ARBs and ACEIs. Only cohort studies were significantly related to achieving better results (RR=0.513, 95% CI= 0.442-0.597, P<0.0001).

Conclusion:

Despite the small number and heterogeneity of the studies evaluating the relationship between treatment with ARBs and ACEIs and the development of HCC, our meta-analysis demonstrates that they may reduce the risk of HCC.

Development of a 1,3a,6a-triazapentalene derivative as a compact and thiol-specific fluorescent labeling reagent

For the fluorescence imaging of biologically active small compounds, the development of compact fluorophores that do not perturb bioactivity is required. Here we report a compact derivative of fluorescent 1,3a,6a-triazapentalenes, 2-isobutenylcarbonyl-1,3a,6a-triazapentalene (TAP-VK1), as a fluorescent labeling reagent. The reaction of TAP-VK1 with various aliphatic thiols proceeds smoothly to afford the corresponding 1,4-adducts in high yields, and nucleophiles other than thiols do not react. After the addition of thiol groups in dichloromethane, the emission maximum of TAP-VK1 shifts to a shorter wavelength and the fluorescence intensity is substantially increased. The utility of TAP-VK1 as a compact fluorescent labeling reagent is clearly demonstrated by the labeling of Captopril, which is a small molecular drug for hypertension. The successful imaging of Captopril, one of the most compact drugs, in this study demonstrates the usefulness of compact fluorophores for mechanistic studies.

Weighing the prognostic role of hyponatremia in hospitalized patients with metastatic solid tumors: the HYPNOSIS study

Previous works linked low sodium concentration with mortality risk in cancer. We aimed at weighing the prognostic impact of hyponatremia in all consecutive patients with metastatic solid tumors admitted in a two-years period at our medical oncology department. Patients were included in two cohorts based on serum sodium concentration on admission. A total of 1025 patients were included, of whom 279 (27.2%) were found to be hyponatremic. The highest prevalence of hyponatremia was observed in biliary tract (51%), prostate (45%) and small-cell lung cancer (38.9%). With a median follow-up of 26.9 months, median OS was 2 months and 13.2 months for the hyponatremia versus control cohort, respectively (HR, 2.65; P < 0.001). In the multivariable model, hyponatremia was independently associated with poorer OS (HR, 1.66; P < 0.001). According to the multivariable model, a nomogram system was developed and validated in an external set of patients. We weighed over time the influence of hyponatremia on survival of patients with metastatic solid tumors and pointed out the possibility to exploit serum sodium assessment to design integrated prognostic tools. Our study also highlights the need for a deeper characterization of the biological role of extracellular sodium levels in tumor development and progression.

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.

Cardiovascular, antidepressant and immunosuppressive drug use in relation to risk of cutaneous melanoma: a protocol for a prospective case-control study

INTRODUCTION

The incidence of cutaneous melanoma (hereafter melanoma) has increased dramatically among fair-skinned populations worldwide. In Norway, melanoma is the most rapidly growing type of cancer, with a 47% increase among women and 57% among men in 2000-2016. Intermittent ultraviolet exposure early in life and phenotypic characteristics like a fair complexion, freckles and nevi are established risk factors, yet the aetiology of melanoma is multifactorial. Certain prescription drugs may have carcinogenic side effects on the risk of melanoma. Some cardiovascular, antidepressant and immunosuppressive drugs can influence certain biological processes that modulate photosensitivity and immunoregulation. We aim to study whether these drugs are related to melanoma risk.

METHODS AND ANALYSIS

A population-based matched case-control study will be conducted using nation-wide registry data. Cases will consist of all first primary, histologically verified melanoma cases diagnosed between 2007 and 2015 identified in the Cancer Registry of Norway (14 000 cases). Ten melanoma-free controls per case (on date of case melanoma diagnosis) will be matched based on sex and year of birth from the National Registry of Norway. For the period 2004-2015, and by using the unique personal identification numbers assigned to all Norwegian citizens, the case-control data set will be linked to the Norwegian Prescription Database for information on drugs dispensed prior to the melanoma diagnosis, and to the Medical Birth Registry of Norway for data regarding the number of child births. Conditional logistic regression will be used to estimate associations between drug use and melanoma risk, taking potential confounding factors into account.

ETHICS AND DISSEMINATION

The project is approved by the Regional Committee for Medical Research Ethics in Norway and by the Norwegian Data Protection Authority. The study is funded by the Southeastern Norway Regional Health Authority. Results will be published in peer-reviewed journals and disseminated further through scientific conferences, news media and relevant patient interest groups.