Association between calcium channel blockers and breast cancer: a meta-analysis of observational studies

Genetic proxies for calcium channel blockers and cancer: a Mendelian randomization study

Calcium channel blockers (CCBs) are commonly prescribed antihypertensives. However, concerns exist about potential off-target effects on cancer. This Mendelian randomization (MR) study examined the associations of genetic proxies for CCBs with the risk of cancer. We used published genetic proxies in the target genes of CCBs as instruments, and obtained MR estimates by applying them to large studies of 17 site-specific cancers (non-Hodgkin lymphoma, melanoma, leukemia, thyroid, rectal, pancreatic, oral cavity/pharyngeal, kidney, esophagus/stomach, colon, bladder, endometrial, cervical and breast, prostate, lung and ovarian cancer) from the Pan-Cancer study, with replication for breast cancer (133,384 cases, 113,789 controls from the Breast Cancer Association Consortium), prostate cancer (79,148 cases, 61,106 controls from the Prostate Cancer Association Group to Investigate Cancer Associated Alterations in the Genome consortium), lung cancer (11,348 cases, 15,861 controls from the International Lung Cancer Consortium), and ovarian cancer (25,509 cases, 40,941 controls from the Ovarian Cancer Association Consortium). We used inverse variance weighting for the main analysis and the weighted median, MR-Egger and Mendelian Randomization Pleiotropy Residual Sum and Outlier as sensitivity analyses. Genetic proxies for CCBs were not associated with any cancer after Bonferroni-correction (at the threshold of p < 0.003). Associations were robust to different MR methods. In conclusion, our study suggests no association of genetic proxies for CCBs with 17 different cancers. While the findings add some support to the safety profile of CCBs in long-term use, future replication is necessary to provide definitive evidence.

Clinical and Biological Predictors of Cancer Incidence and Mortality in Patients with Stable Coronary Artery Disease

Clinical and epidemiological evidence has recently revealed a link between coronary artery disease (CAD) and cancer. Shared risk factors and common biological pathways are probably involved in both pathological conditions. The aim of this paper was to evaluate whether and which conventional risk factors and novel circulating biomarkers could predict cancer incidence and death in patients with CAD. The study included 750 CAD patients, who underwent blood sampling for the evaluation of systemic inflammatory indexes (NLR and SII) and specific biomarkers of oxidative damage (leukocyte telomere length (LTL), mitochondrial DNA copy number (mtDNAcn)). Study participants were followed up for a mean of 5.4 ± 1.2 years. Sixty-seven patients (8.9%) developed cancer during the follow-up time, and nineteen (2.5%) died of cancer. Cox multivariable analysis revealed that age (HR = 1.071; 95% CI: 1.034-1.109; p < 0.001), smoking habit (HR = 1.994; 95% CI: 1.140-3.488; p = 0.016), obesity (HR = 1.708; 95% CI: 1.022-2.854; p = 0.041) and SII (HR = 1.002; 95% CI: 1.001-1.003; p = 0.045) were associated with cancer incidence, while only age (HR = 1.132; 95% CI: 1.052-1.219; p = 0.001) was a predictor of cancer death. Patients with lung and gastrointestinal cancers had significantly higher median mtDNAcn levels than those without cancer. Our study suggests that aggressive risk factor modification and suppression of chronic inflammation may be essential to preventing cancer in CAD patients.

CACNA1D overexpression and voltage-gated calcium channels in prostate cancer during androgen deprivation

Prostate cancer is often treated by perturbing androgen receptor signalling. CACNA1D, encoding Ca_V1.3 ion channels is upregulated in prostate cancer. Here we show how hormone therapy affects CACNA1D expression and Ca_V1.3 function. Human prostate cells (LNCaP, VCaP, C4-2B, normal RWPE-1) and a tissue microarray were used. Cells were treated with anti-androgen drug, Enzalutamide (ENZ) or androgen-removal from media, mimicking androgen-deprivation therapy (ADT). Proliferation assays, qPCR, Western blot, immunofluorescence, Ca²⁺-imaging and patch-clamp electrophysiology were performed. Nifedipine, Bay K 8644 (Ca_V1.3 inhibitor, activator), mibefradil, Ni²⁺ (Ca_V3.2 inhibitors) and high K⁺ depolarising solution were employed. CACNA1D and Ca_V1.3 protein are overexpressed in prostate tumours and CACNA1D was overexpressed in androgen-sensitive prostate cancer cells. In LNCaP, ADT or ENZ increased CACNA1D time-dependently whereas total protein showed little change. Untreated LNCaP were unresponsive to depolarising high K⁺/Bay K (to activate Ca_V1.3); moreover, currents were rarely detected. ADT or ENZ-treated LNCaP exhibited nifedipine-sensitive Ca²⁺-transients; ADT-treated LNCaP exhibited mibefradil-sensitive or, occasionally, nifedipine-sensitive inward currents. CACNA1D knockdown reduced the subpopulation of treated-LNCaP with Ca_V1.3 activity. VCaP displayed nifedipine-sensitive high K⁺/Bay K transients (responding subpopulation was increased by ENZ), and Ni²⁺-sensitive currents. Hormone therapy enables depolarization/Bay K-evoked Ca²⁺-transients and detection of Ca_V1.3 and Ca_V3.2 currents. Physiological and genomic CACNA1D/Ca_V1.3 mechanisms are likely active during hormone therapy-their modulation may offer therapeutic advantage.

The risk of second primary malignancies in colorectal cancer patients using calcium channel blockers

Calcium channel blockers are among the most commonly used agents in the treatment of cardiovascular diseases. There are several known side-effects associated with their long-term use, whereas other potential adverse effects are yet to be proven. This study aims to evaluate the association between calcium channel blockers exposure and the incidence of second primary malignancy. We established a cohort of 1401 patients with colorectal cancer diagnosed in our institution between January 2003 and December 2016. Patients were followed-up until December 2020. The tumor characteristics and basic clinical data including medication information were obtained from the hospital information system database. Second malignancy was detected in 301 patients (21.5%), and occurred in 27.8% of patients who used calcium channel blockers compared to only 19.9% among non-users. Their use was associated with an increased incidence of bladder cancer in particular. Subanalysis of patients with second malignancy displayed a higher proportion of right-sided colon cancer compared to rectal carcinoma in non-users. Survival analysis revealed significantly better outcomes in early-stage colorectal cancer patients without a history of calcium channel blockers treatment or second primary malignancy.

High expression of N-type calcium channel indicates a favorable prognosis in gliomas

For the diagnosis and prognosis of glioma, the development of prognostic biomarkers is critical. The N-type calcium channel, whose predominant subunit is encoded by calcium voltage-gated channel subunit alpha1 B (CACNA1B), is mostly found in the nervous system and is closely associated with neurosensory functions. However, the link between the expression of CACNA1B and glioma remains unknown. We used ONCOMINE to explore the differences in CACNA1B expression among different cancers. We then conducted survival analysis and COX analysis using TCGA_LGG and TCGA_GBM datasets, which were divided into CACNA1Bhigh and CACNA1Blow based on the median. We examined the differences in other favorable prognostic markers or clinical characteristics between CACNA1Bhigh and CACNA1Blow using t tests. Differentially expressed genes were identified, and KEGG pathway enrichment was performed. We compared the expression of methyltransferases and analyzed the differentially methylated regions. Immunohistochemistry results were retrieved from the Human Protein Atlas database for validation purposes. CACNA1B was expressed at lower levels in gliomas, and, for the first time, we found that high expression of CACNA1B in gliomas predicts a good prognosis. Other favorable prognostic markers, such as isocitrate dehydrogenase mutation, 1p/19q codeletion, and O6-methylguanine-DNA methyltransferase promoter methylation, were increased in tandem with high expression of CACNA1B. Differentially expressed genes were enriched in multiple pathways related to cancer progression and aberrant epigenetic alterations were significantly associated with CACNA1B. High expression of N-type calcium channels indicates a favorable prognosis for gliomas. This study provides a better understanding of the link between gliomas and N-type calcium channels and may offer guidance for the future treatment of gliomas.

Calcium Channel Blocker Use and the Risk for Breast Cancer: A Population-Based Nested Case-Control Study

Simple Summary

Calcium channel blockers (CCBs) are widely used among hypertension and heart disease patients. These drugs are effective and well-tolerated. Some studies have found that patients who used CCBs have a higher incidence of breast cancer (BCa). However, other studies did not find such an association. We investigate whether exposure to CCBs in patients with hypertension is associated with an increased risk of BCa. From a cohort of patients prescribed their first antihypertensive medication between 2000 and 2016, we detected 4875 BCa cases. For each case, we matched ten patients without BCa (controls). We found no association between CCB users and an increased risk of BCa compared to the use of other antihypertensive medications. There was no increase in risk even with longer exposure to CCBs (above eight years) and high doses. Considering that CCBs are a widely used antihypertensive drug class, our results provide important safety information on a population level, especially for patients with increased BCa risk.

Abstract

We investigated whether long-term exposure to calcium channel blockers (CCBs) is associated with an increased risk of breast cancer (BCa). We designed a nested case–control study based on data from the Clalit electronic database, the largest Israeli Health Services organization. All newly diagnosed breast cancer (BCa) cases were selected from a cohort of patients with hypertension. Ten controls were matched for each BCa case. The odds ratios (ORs) of BCa among CCBs users were calculated using multivariate conditional logistic regression analyses. A total of 4875 patients with newly diagnosed BCa were identified from the cohort with a median follow-up of 5.15 years. The exposure to CCBs was not associated with an increased risk of BCa (OR = 0.98; 95% CI, 0.92–1.04). Additionally, there was no association between long-term exposure to CCBs (above eight years) and increased BCa risk (OR = 0.91; 95% CI, 0.67–1.21). Higher cumulative doses of CCBs were not associated with an elevated risk of BCa (OR = 0.997; 95% CI, 0.962–1.034, calculated per 1000 DDD). Based on this large population-based study, long-term exposure to CCBs was not associated with an increased risk of BCa. Considering that CCBs are widely used medications, our results provide important safety information on a population level, especially for patients with an increased risk of BCa.

Calcium Channel Antagonists for Mood Disorders

PURPOSE

Development of new thymoleptic medications has primarily centered on anticonvulsants and antipsychotic drugs. Based on our studies of intracellular calcium ion signaling in mood disorders, we were interested in the use of novel medications that act on this mechanism of neuronal activation as potential mood stabilizers.

METHOD

We reviewed the dynamics of the calcium second messenger system and the international body of data demonstrating increased baseline and stimulated intracellular calcium levels in peripheral cells of patients with bipolar mood disorders. We then examined studies of the effect of established mood stabilizers on intracellular calcium ion levels and on mechanisms of mobilization of this second messenger. After summarizing studies of calcium channel blocking agents, whose primary action is to attenuate hyperactive intracellular calcium signaling, we considered clinical experience with this class of medications and the potential for further research.

FINDINGS

Established mood stabilizers normalize increased intracellular calcium ion levels in bipolar disorder patients. Most case series and controlled studies suggest an antimanic and possibly mood stabilizing effect of the calcium channel blocking medications verapamil and nimodipine, with fewer data on isradipine. A relatively low risk of teratogenicity and lack of cognitive adverse effects or weight gain suggest possible applications in pregnancy and in patients for whom these are considerations.

IMPLICATIONS

Medications that antagonize hyperactive intracellular signaling warrant more interest than they have received in psychiatry. Further experience will clarify the applications of these medications alone and in combination with more established mood stabilizers.

The Risk of Antihypertensive Drug among Breast Cancer Patient: A Systematic Review and Meta-analysis

BACKGROUNDS: Breast cancer or breast carcinoma is the most common type of malignancy in women globally. According to the previous studies that indicate the usage of antihypertensive drugs may become a risk factor of cancer (beta-blockers [BBs], calcium channel blockers [CCBs], and diuretics). Both angiotensin-converting enzymes inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), on the other hand, have been associated to an increased or decreased risk of breast cancer. AIM: To compare each type of antihypertensive medicines as a risk factor for breast cancer, we did a systematic review and meta-analysis of current evidence. METHODS: We utilized the terms “antihypertensive”, “anti-hypertensive”, “anti-hypertensive medications”, “breast cancer”, “risk”, “case control”, and “cohort” in PubMed, ScienceDirect, and Google Scholar databases. RESULTS: Our data calculation found that the risk of antihypertensive drugs was significantly different in overall analysis (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.42–0.83, p = 0.003). Five studies with 39.503 breast cancer patients and 372.037 controls were included in the ARBs user sub-group. Our results found significant different of antihypertensive drugs among breast cancer patient (OR = 1.47, 95% CI = 1.02–2.11 p = 0.04). Our data calculation also confirmed no significant different in antihypertensive drugs among breast cancer patient (OR = 1.07, 95% CI = 0.99–1.16, p = 0.09) in diuretics user, (OR = 1.08, 95% CI = 0.99–1.18, p = 0.08) in CCBs user, (OR = 1.11, 95% CI = 0.98–1.26, p = 0.09) in BBs user, and (OR = 1.27, 95% CI = 0.64–2.50, p = 0.50) in ACEIs user. CONCLUSIONS: Although, the finding reveal that antihypertensive drugs (diuretics, CCBs, BBs, and ACEIs) in overall are significant for the risk of breast cancer and also found that ARBs have a low potential in the risk of breast cancer.

The Use of Antihypertensive Drugs as Coadjuvant Therapy in Cancer

Cancer is a complex group of diseases that constitute the second largest cause of mortality worldwide. The development of new drugs for treating this disease is a long and costly process, from the discovery of the molecule through testing in phase III clinical trials, a process during which most candidate molecules fail. The use of drugs currently employed for the management of other diseases (drug repurposing) represents an alternative for developing new medical treatments. Repurposing existing drugs is, in principle, cheaper and faster than developing new drugs. Antihypertensive drugs, primarily belonging to the pharmacological categories of angiotensin-converting enzyme inhibitors, angiotensin II receptors, direct aldosterone antagonists, β-blockers and calcium channel blockers, are commonly prescribed and have well-known safety profiles. Additionally, some of these drugs have exhibited pharmacological properties useful for the treatment of cancer, rendering them candidates for drug repurposing. In this review, we examine the preclinical and clinical evidence for utilizing antihypertensive agents in the treatment of cancer.

The Relationship Between Anti-Hypertensive Drugs and Cancer: Anxiety to be Resolved in Urgent

Hypertension is the prevailing independent risk factor for cardiovascular disease worldwide. Anti-hypertensive drugs are the common and effective cure for lowering blood pressure in patients with hypertension. However, some large-scale clinical studies have pointed out that long-term ingestion of some oral anti-hypertensive drugs was associated with risks of incident cancer and the survival time. In contrast, other studies argue that anti-hypertensive drugs are not related to the occurrence of cancer, even as a complementary therapy of tumor treatment. To resolve the dispute, numerous recent mechanistic studies using animal models have tried to find the causal link between cancer and different anti-hypertensive drugs. However, the results were often contradictory. Such uncertainties have taken a toll on hypertensive patients. In this review, we will summarize advances of longitudinal studies in the association between anti-hypertensive drugs and related tumor risks that have helped to move the field forward from associative to causative conclusions, in hope of providing a reference for more rigorous and evidence-based clinical research on the topic to guide the clinical decision making.

Protective Association Between Calcium Channel Blocker Use and Breast Cancer Recurrence in Postsurgical Women: A Population-Based Case-Control Study in Taiwan

Neoadjuvant chemotherapy induces metastasis of residual breast cancers through activation of tumor-associated macrophages. Previous studies have indicated that calcium channel blockers (CCBs) exert anti-inflammatory and antimigratory effects on macrophages via attenuating Ca²⁺ entry into macrophages. However, no existing empirical research has addressed the relationship between previous CCB use and breast cancer recurrence. In this study, 4840 Taiwanese women aged ≥20 years with breast cancer who underwent breast surgery from January 1, 2007, to December 31, 2015, were enrolled. The date of cancer recurrence was defined as the index date. Logistic regression was performed to evaluate the relationship between previous CCB exposure and cancer recurrence among female patients who underwent surgery for breast cancer. After adjusting for demographic characteristics, comorbidities, and tumor-node-metastasis stage, the adjusted odds ratio (OR) for CCB exposure within 5 years before the index date in women with recurrence compared with nonrecurrent controls was 0.73 (95% confidence interval [CI], 0.53-0.97). Further analysis revealed that the adjusted OR for CCB exposure between the surgery and index dates in women with recurrence relative to nonrecurrent controls was 0.72 (95%CI, 0.66-0.95). In particular, prior CCB use was significantly associated with a lower risk (34%) of breast cancer recurrence among women 20 to 54 years old (OR, 0.66; 95%CI, 0.47-0.83). This study uncovered a protective association between previous CCB use and breast cancer recurrence.

Verification of the effects of calcium channel blockers on the immune microenvironment of breast cancer

BACKGROUND

A higher density of tumor-infiltrating lymphocytes (TILs) can lead to greater therapeutic effects and improved prognoses in cancer treatment. Similar results have been observed in breast cancer, particularly in triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2-enriched breast cancer. Calcium channel blockers (CCBs) are antihypertensive drugs (AHTs) that have also been reported to suppress the functions of T cells and macrophages. In this study, we evaluated TILs before pre-operative chemotherapy (POC) in breast cancer and retrospectively analyzed the correlation between CCBs and TILs or prognosis.

METHODS

Of the patients treated with POC, 338 who had evaluable TILs were enrolled in this study. The correlations among TILs were evaluated according to standard methods, and CCB use and prognosis were investigated retrospectively.

RESULTS

Before POC, 65 patients (19.2%) took AHTs (CCBs: 41/338, 12.1%). The TIL density was significantly lower among patients administered CCBs for the group of all patients and for patients with TNBC (p = 0.040, p = 0.009, respectively). Additionally, patients with TNBC who were administered CCBs showed significantly lower response rates for POC (p = 0.040). In all patients receiving POC, no significant differences in disease-free survival (DFS) or overall survival (OS) were observed in patients administered CCBs (p = 0.712, p = 0.478, log-rank tests, respectively). Furthermore, no significant differences were found, even in patients with TNBC (DFS: p = 0.441, OS: p = 0.727, log-rank tests, respectively).

CONCLUSIONS

In patients with TNBC undergoing treatment for hypertension with CCBs, TILs in the needle biopsy specimens before treatment were significantly lower, and the response rate of POC was not sufficient. Thus, the immunosuppressive effects of CCBs may also affect the immune microenvironment.

Use of Calcium Channel Blockers and Risk of Breast Cancer: A Population-based Cohort Study

BACKGROUND

Several observational studies have associated use of calcium channel blockers with an increased risk of breast cancer, but this association remains controversial. The objective of this study was to determine whether these drugs are associated with an increased risk of breast cancer overall, and to assess whether this risk varies with cumulative duration of use.

METHODS

We identified a cohort of 273,152 women newly treated with antihypertensive drugs between 1 January 1995 and 31 December 2009, followed until 31 December 2010, using the UK Clinical Practice Research Datalink. We treated calcium channel blocker use as a time-varying variable, and lagged exposure by 1 year for latency considerations and to minimize reverse causality. We used time-dependent Cox proportional hazards models to estimate adjusted hazard ratios with 95% confidence intervals of incident breast cancer associated with use of calcium channel blockers overall and by cumulative duration of use (<5, 5-10, and ≥10 years).

RESULTS

During 1,567,104 person-years of follow-up, 4,520 women were newly diagnosed with breast cancer (incidence rate: 2.9 per 1,000 per year). Compared with use of other antihypertensive drugs, use of calcium channel blockers was not associated with increased risk of breast cancer overall (hazard ratio: 0.97, 95% confidence interval: 0.91, 1.03). Similarly, there was no evidence of a duration-response relationship in terms of cumulative duration of use (P trend = 0.26).

CONCLUSIONS

The results of this large population-based study indicate that long-term use of calcium channel blockers is not associated with an increased risk of breast cancer.

Stress Echocardiography Positivity Predicts Cancer Death

BACKGROUND

Stress echocardiography (SE) predicts cardiac death, but an increasing share of cardiac patients eventually die of cancer. The aim of the study was to assess whether SE positivity predicts cancer death.

METHODS AND RESULTS

In a retrospective analysis of prospectively acquired single-center, observational data, we evaluated 4673 consecutive patients who underwent SE from 1983 to 2009. All patients were cancer-free at index SE and were followed up for a median of 131 months (interquartile range 134). We separately analyzed predetermined end points: cardiovascular, cancer, and noncardiovascular, noncancer death, with and without competing risk. SE was positive in 1757 and negative in 2916 patients; 869 cardiovascular, 418 cancer, and 625 noncardiovascular, noncancer deaths were registered. The 25-year mortality was higher in SE-positive than in SE-negative patients, considering cardiovascular (40% versus 31%; P<0.001) and cancer mortality (26% versus 17%; P<0.01). SE positivity was a strong predictor of cancer (cause-specific hazard ratio 1.19; 95% confidence interval, 1.16-1.73; P=0.05) and cardiovascular mortality (1.18; 95% confidence interval, 1.03-1.35; P=0.02). Fine-Gray analysis to account for competing risk gave similar results. Cancer risk diverged after 15 years, whereas differences were already significant at 5 years for cardiovascular risk.

CONCLUSIONS

SE results predict cardiovascular and cancer mortality. SE may act as a proxy of the shared risk factor milieu for cancer or cardiovascular death.

Calcium channel blockers and breast cancer incidence: An updated systematic review and meta-analysis of the evidence

Controversy exists regarding the potential association between taking calcium channel blockers (CCBs) and the development of breast cancer. As a positive association would have important public health implications due to the widespread use of CCBs, this study aimed to incorporate new evidence to determine whether an association is likely to exist. We searched MEDLINE, EMBASE and the Cochrane Library to 28 June 2016 for relevant literature. References and citing articles were checked and authors contacted as necessary. Two authors independently selected articles and extracted data. Twenty-nine studies were reviewed; 26 were non-randomised studies (NRS). Meta-analysis of study data where adjustment for 'confounding by indication' was judged to be present suggests that an association, if any, is likely to be modest in magnitude (pooled odds/risk ratio 1.09 (95% confidence interval (CI) 1.03-1.15, I²=0%, 8 sub-studies; pooled hazard ratio 0.99 (95% CI 0.94-1.03, I²=35%, 9 sub-studies)). There are credible study data showing an increased relative risk with long-term use of CCBs, but the results of our meta-analysis and of meta-regression of log relative risk against minimum follow-up time are mixed. The current summative evidence does not support a clear association between taking CCBs and developing breast cancer. However, uncertainty remains, especially for long-term use and any association might not be uniform between different populations and/or breast cancer sub-types. We thus recommend further NRS in settings where CCB use is highly prevalent and population-based cancer, prescription and health-registries exist, to resolve this continuing uncertainty. PROSPERO, CRD42015026712.

Antihypertensive drug use and breast cancer risk: a meta-analysis of observational studies

We conducted a meta-analysis of observational studies to examine the hypothesized association between breast cancer and antihypertensive drug (AHT) use. Fixed- or random- effect models were used to calculate pooled risk ratios (RRs) and 95% confidence intervals (CIs) for all AHTs and individual classes (i.e., angiotensin-converting enzyme inhibitors, [ACEi]; angiotensin-receptor blockers, [ARBs]; calcium channel blockers, [CCBs]; beta-blockers, [BBs], and diuretics). Twenty-one studies with 3,116,266 participants were included. Overall, AHT use was not significantly associated with breast cancer risk (RR = 1.02, 95% CI: 0.98-1.06), and no consistent association was found for specific AHT classes with pooled RRs of 1.02 (95% CI: 0.96-1.09) for BBs, 1.07 (95% CI: 0.99-1.16) for CCBs, 0.99 (95% CI: 0.93-1.05) for ACEi/ARBs, and 1.05 (95% CI: 0.99-1.12) for diuretics. When stratified by duration of use, there was a significantly reduced breast cancer risk for ACEi/ARB use ≥10 years (RR = 0.80, 95% CI: 0.67-0.95). Although there was no significant association between AHT use and breast cancer risk, there was a possible beneficial effect was found for long-term ACEi/ARB. Large, randomized controlled trials with long-term follow-up are needed to further test the effect of these medications on breast cancer risk.

Voltage-gated calcium channels: Novel targets for cancer therapy

Voltage-gated calcium channels (VGCCs) comprise five subtypes: The L-type; R-type; N-type; P/Q-type; and T-type, which are encoded by α₁ subunit genes. Calcium ion channels also have confirmed roles in cellular functions, including mitogenesis, proliferation, differentiation, apoptosis and metastasis. An association between VGCCs, a reduction in proliferation and an increase in apoptosis in prostate cancer cells has also been reported. Therefore, in the present study, the online clinical database Oncomine was used to identify the alterations in the mRNA expression level of VGCCs in 19 cancer subtypes. Overall, VGCC family genes exhibited under-expression in numerous types of cancer, including brain, breast, kidney and lung cancers. Notably, the majority of VGCC family members (CACNA1C, CACNA1D, CACNA1A, CACNA1B, CACNA1E, CACNA1H and CACNA1I) exhibited low expression in brain tumors, with mRNA expression levels in the top 1–9% of downregulated gene rankings. A total of 5 VGCC family members (CACNA1A, CACNA1B, CACNA1E, CACNA1G and CACNA1I) were under-expressed in breast cancer, with a gene ranking in the top 1–10% of the low-expressed genes compared with normal tissue. In kidney and lung cancers, CACNA1S, CACNA1C, CACNA1D, CACNA1A and CACNA1H exhibited low expression, with gene rankings in the top 1–8% of downregulated genes. In conclusion, the present findings may contribute to the development of new cancer treatment approaches by identifying target genes involved in specific types of cancer.

Hypertension and breast cancer risk: a systematic review and meta-analysis

Observational studies examining the relationship between hypertension and breast cancer risk have reported conflicting findings. We conducted this systematic review and meta-analysis to summarize the evidence regarding the association between hypertension and risk of breast cancer. Eligible studies were identified through a comprehensive literature search of PubMed, EMBASE, and the Cochrane library until August 2016. We included observational studies that reported relative risks (RR) with corresponding 95% confidence intervals (CIs). Results from individual studies were pooled by using a random-effects model. 29 articles of 30 studies, with totally 11643 cases of breast cancer, were eligible for inclusion in the meta-analysis. We observed a statistically significant association between hypertension and increased breast cancer risk (RR: 1.15; 95% CI: 1.08, 1.22). In the subgroup analysis, we found a positive association between hypertension and breast cancer incidence among postmenopausal women (RR: 1.20; 95% CI: 1.09, 1.31). In contrast, hypertension was not associated with risk of breast cancer among premenopausal women (RR: 0.97; 95% CI: 0.84, 1.12) and Asian population (RR: 1.07; 95% CI: 0.94, 1.22).This meta-analysis collectively suggests a significantly association between hypertension and breast cancer risk, specifically for postmenopausal hypertensive women.

CaV channels and cancer: canonical functions indicate benefits of repurposed drugs as cancer therapeutics

The importance of ion channels in the hallmarks of many cancers is increasingly recognised. This article reviews current knowledge of the expression of members of the voltage-gated calcium channel family (Ca_V) in cancer at the gene and protein level and discusses their potential functional roles. The ten members of the Ca_V channel family are classified according to expression of their pore-forming α-subunit; moreover, co-expression of accessory α2δ, β and γ confers a spectrum of biophysical characteristics including voltage dependence of activation and inactivation, current amplitude and activation/inactivation kinetics. Ca_V channels have traditionally been studied in excitable cells including neurones, smooth muscle, skeletal muscle and cardiac cells, and drugs targeting the channels are used in the treatment of hypertension and epilepsy. There is emerging evidence that several Ca_V channels are differentially expressed in cancer cells compared to their normal counterparts. Interestingly, a number of Ca_V channels also have non-canonical functions and are involved in transcriptional regulation of the expression of other proteins including potassium channels. Pharmacological studies show that Ca_V canonical function contributes to the fundamental biology of proliferation, cell-cycle progression and apoptosis. This raises the intriguing possibility that calcium channel blockers, approved for the treatment of other conditions, could be repurposed to treat particular cancers. Further research will reveal the full extent of both the canonical and non-canonical functions of Ca_V channels in cancer and whether calcium channel blockers are beneficial in cancer treatment.

Meta-Analysis of Public Microarray Datasets Reveals Voltage-Gated Calcium Gene Signatures in Clinical Cancer Patients

Voltage-gated calcium channels (VGCCs) are well documented to play roles in cell proliferation, migration, and apoptosis; however, whether VGCCs regulate the onset and progression of cancer is still under investigation. The VGCC family consists of five members, which are L-type, N-type, T-type, R-type and P/Q type. To date, no holistic approach has been used to screen VGCC family genes in different types of cancer. We analyzed the transcript expression of VGCCs in clinical cancer tissue samples by accessing ONCOMINE (www.oncomine.org), a web-based microarray database, to perform a systematic analysis. Every member of the VGCCs was examined across 21 different types of cancer by comparing mRNA expression in cancer to that in normal tissue. A previous study showed that altered expression of mRNA in cancer tissue may play an oncogenic role and promote tumor development; therefore, in the present findings, we focus only on the overexpression of VGCCs in different types of cancer. This bioinformatics analysis revealed that different subtypes of VGCCs (CACNA1C, CACNA1D, CACNA1B, CACNA1G, and CACNA1I) are implicated in the development and progression of diverse types of cancer and show dramatic up-regulation in breast cancer. CACNA1F only showed high expression in testis cancer, whereas CACNA1A, CACNA1C, and CACNA1D were highly expressed in most types of cancer. The current analysis revealed that specific VGCCs likely play essential roles in specific types of cancer. Collectively, we identified several VGCC targets and classified them according to different cancer subtypes for prospective studies on the underlying carcinogenic mechanisms. The present findings suggest that VGCCs are possible targets for prospective investigation in cancer treatment.

Long-Term Use of Antihypertensive Agents and Risk of Breast Cancer: A Population-Based Case-Control Study

INTRODUCTION

To evaluate the risk of breast cancer associated with long-term use of antihypertensive agents (AHs) in Taiwanese women with hypertension.

METHODS

A search of the Taiwan National Health Insurance Research Database identified 330,699 patients with hypertension who were treated with antihypertensive drugs between January 1, 1998 and December 31, 2011. Logistic regression models were used to estimate the odds ratios (ORs) and 95% confidence intervals (CIs) between the use of AHs and breast cancer risk, adjusted for other types of antihypertensive drugs, statins and co-morbidities.

RESULTS

Among the AHs used to treat the hypertensive women enrolled in our study, our analysis revealed that those treated with one specific particular class of beta-blockers (beta-1 selective beta-blockers) had an increased risk for breast cancer. We also found that the ever-use of calcium channel blockers (CCBs; i.e. for 13 years) was associated with breast cancer in an adjusted model (OR 1.09; 95% CI 1.03-1.16). However, the use of nonselective beta-blockers, selective and nonselective alpha-blockers, angiotensin-converting enzyme inhibitors and angiotensin II antagonists were not associated with breast cancer risk.

CONCLUSION

Based on the results of our analysis, long-term use of CCBs or beta-1 selective beta-blockers are likely to be associated with the risk of breast cancer. Further large comprehensive population-based studies to support our findings are required for confirmation of this conclusion.