Calcium channel blockers, apoptosis and cancer: is there a biologic relationship?

Cancer and Cardiovascular Disease: The Conjoined Twins

Cancer and cardiovascular disease are the two most common causes of death worldwide. As the fields of cardiovascular medicine and oncology continue to expand, the area of overlap is becoming more prominent demanding dedicated attention and individualized patient care. We have come to realize that both fields are inextricably intertwined in several aspects, so much so that the mere presence of one, with its resultant downstream implications, has an impact on the other. Nonetheless, cardiovascular disease and cancer are generally approached independently. The focus that is granted to the predominant pathological entity (either cardiovascular disease or cancer), does not allow for optimal medical care for the other. As a result, ample opportunities for improvement in overall health care are being overlooked. Herein, we hope to shed light on the interconnected relationship between cardiovascular disease and cancer and uncover some of the unintentionally neglected intricacies of common cardiovascular therapeutics from an oncologic standpoint.

Use of calcium channel blockers and risk of breast cancer among women aged 55 years and older: a nationwide population-based cohort study

This retrospective cohort study was aimed to compare the incidence of breast cancer among women aged ≥55 who received calcium channel blockers and angiotensin converting enzyme inhibitors/angiotensin II receptor blockers. We used the 2002-2015 Health and Welfare Database in Taiwan. Women 55 years and older who initiated antihypertensive treatment were included. Breast cancer risk for patients receiving calcium channel blockers was compared to those receiving angiotensin converting enzyme inhibitors/angiotensin II receptor blockers. Cox proportional hazards models were used to generate adjusted hazard ratios for breast cancer. We found that the risk of breast cancer was similar between calcium channel blockers users and angiotensin converting enzyme inhibitors/angiotensin II receptor blockers (adjusted hazard ratio [aHR] and 95% CI = 1.03 [0.80 to 1.34]). No significant risk increase was observed in the stratified analysis by dihydropyridine (aHR = 1.02 [0.78 to 1.33]) and non-dihydropyridine calcium channel blockers (aHR = 1.23 [0.48 to 3.20]). No difference in the risk of breast cancer associated with calcium channel blockers exposure was observed in patients who used hormone replacement therapy (aHR = 1.02 [0.29 to 3.58]). The risk for breast cancer was observed to be significantly lower in patients receiving calcium channel blockers than in those receiving angiotensin converting enzyme inhibitors/angiotensin II receptor blockers at a treatment duration of 5 or more years (aHR = 0.57 [0.33 to 0.98]). In conclusion, the risk for breast cancer is similar for calcium channel blockers and angiotensin converting enzyme inhibitors/angiotensin II receptor blocker users in an Asian population.

Repurposing drugs targeting metabolic diseases for cancer therapeutics

Hurdles in the identification of new drugs for cancer treatment have made drug repurposing an increasingly appealing alternative. The approach involves the use of old drugs for new therapeutic purposes. It is cost-effective and facilitates rapid clinical translation. Given that cancer is also considered a metabolic disease, drugs for metabolic disorders are being actively repurposed for cancer therapeutics. In this review, we discuss the repurposing of such drugs approved for two major metabolic diseases, diabetes and cardiovascular disease (CVD), which have shown potential as anti-cancer treatment. We also highlight the current understanding of the cancer signaling pathways that these drugs target.

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.

Are calcium channel blockers related to lung cancer?

Background:

Calcium channel blocker (CCB) is a common antihypertensive agent for the treatment of hypertension. There are inconsistent data of an association of CCB and lung cancer in the literature. This study aimed to evaluate this association by a case-control design.

Methods:

The inclusion criteria were adult patients 18 years or over, diagnosed with hypertension, lung cancer or pulmonary tuberculosis, and presenting with one of the suggestive symptoms of lung cancer. Those who were pregnant or had a diagnosis of lung cancer or pulmonary tuberculosis prior to the diagnosis of hypertension were excluded. Diagnosis of lung cancer was made pathologically, while tuberculosis was made by positive acid-fast bacilli on sputum examination, sputum culture positive for Mycobacterium tuberculosis, or polymerase chain reaction positive for M. tuberculosis with a chest x-ray compatible with tuberculosis. Cases were those diagnosed with lung cancer, while controls were those diagnosed with tuberculosis. Factors associated with lung cancer were calculated by logistic regression analysis.

Results:

There were 178 patients who met the study criteria. Of those, 69 patients (38.8%) were in the case group. The lung cancer group had EGFR gene mutation in 21 patients (52.5%) and adenocarcinoma was the most common cell type of lung cancer (55 patients; 79.7%). There were two factors independently associated with lung cancer including dyslipidemia and family history of lung cancer.

Conclusions:

CCB was not associated with lung cancer in patients with hypertension but dyslipidemia and family history of lung cancer were independently associated with lung cancer in this setting.

Long-term use of antihypertensive medications, hypertension and colorectal cancer risk and mortality: a prospective cohort study

BACKGROUND

Hypertension and the use of antihypertensive medications have been intensively investigated in relation to colorectal cancer (CRC). Prior epidemiologic studies have not been able to examine this topic with adequate confounding control and follow-up time, or disentangle the effects of antihypertensive agents and hypertension.

METHODS

Eligible participants in the Nurses' Health Study and Health Professionals Follow-up Study were followed for up to 28 years, with repeat assessments of exposures. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals.

RESULTS

In fully adjusted analyses based on both new-user and prevalent-user designs, there was no association between the use of beta-blockers, calcium-channel blockers, thiazide diuretics, angiotensin-converting enzyme inhibitors, furosemide, other antihypertensive drugs and CRC risk and mortality reached the statistically significant threshold after Bonferroni correction. The results remained similar in sensitivity analyses among participants with hypertension. Before Bonferroni correction, suggestive associations between beta-blocker use and CRC risk and between furosemide use and CRC-specific mortality were observed specifically in analyses using a new-user design. Hypertension was not associated with CRC risk in analyses based on both new-user and prevalent-user designs.

CONCLUSIONS

Hypertension and long-term use of major classes of antihypertensive medications are unlikely to be associated with CRC risk and mortality.

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.

T-Type Calcium Channel Inhibitors Induce Apoptosis in Medulloblastoma Cells Associated with Altered Metabolic Activity

Medulloblastoma (MB) is the most common malignant paediatric brain tumour. In our previous studies, we developed a novel 3D assay for MB cells that was used to screen a panel of plasma membrane calcium channel modulators for their effect on the 3D growth of D341 MB cells. These studies identified T-type (CaV3) channel inhibitors, mibefradil and NNC-55-0396 (NNC) as selective inhibitors of MB cell growth. Mibefradil was originally approved for the treatment of hypertension and angina pectoris, and recently successfully completed a phase I trial for recurrent high-grade glioma. NNC is an analogue of mibefradil with multiple advantages compared to mibefradil that makes it attractive for potential future clinical trials. T-type channels have a unique low voltage-dependent activation/inactivation, and many studies suggest that they have a direct regulatory role in controlling Ca²⁺ signalling in non-excitable tissues, including cancers. In our previous study, we also identified overexpression of CaV3.2 gene in MB tissues compared to normal brain tissues. In this study, we aimed to characterise the effect of mibefradil and NNC on MB cells and elucidate their mechanism of action. This study demonstrates that the induction of toxicity in MB cells is selective to T-type but not to L-type Ca²⁺ channel inhibitors. Addition of CaV3 inhibitors to vincristine sensitised MB cells to this MB chemotherapeutic agent, suggesting an additive effect. Furthermore, CaV3 inhibitors induced cell death in MB cells via apoptosis. Supported by proteomics data and cellular assays, apoptotic cell death was associated with reduced mitochondrial membrane potential and reduced ATP levels, which suggests that both compounds alter the metabolism of MB cells. This study offers new insights into the action of mibefradil and NNC and will pave the way to test these molecules or their analogues in pre-clinical MB models alone and in combination with vincristine to assess their suitability as a potential MB therapy.

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.

Antihypertensive medication use and ovarian cancer survival

OBJECTIVE

Although experimental models suggest that use of beta-blockers, a common antihypertensive agent, may improve survival in ovarian cancer patients, results from clinical studies have been mixed.

METHODS

We evaluated the associations of pre-diagnostic (n = 950) and post-diagnostic (n = 743) use of antihypertensive medications with survival among patients with invasive, epithelial ovarian cancer in the Nurses' Health Study (NHS; 1994-2016) and NHSII (2001-2017), with follow-up until 2018 and 2019, respectively. Cox proportional hazards models were used to estimate hazard ratios (HR) for ovarian cancer mortality according to antihypertensive medication use before and after diagnosis, considering multiple drug classes (beta-blockers, calcium-channel blockers, thiazide diuretics, angiotensin-converting enzyme [ACE] inhibitors).

RESULTS

After adjusting for age, BMI, smoking status and tumor characteristics, pre-diagnostic use versus non-use of calcium-channel blockers was associated with higher ovarian cancer mortality (HR: 1.49; 95% CI: 1.13, 1.96), which was primarily due to polytherapy involving calcium-channel blockers (HR: 1.61; 95% CI: 1.15, 2.26). Pre-diagnostic use of beta-blockers, thiazide diuretics, or ACE inhibitors was not associated with ovarian cancer mortality. No association was observed for post-diagnostic antihypertensive medication use individually or in combination, except for lower mortality associated with polytherapy involving ACE inhibitors (HR: 0.53; 95% CI: 0.31, 0.91).

CONCLUSION

Overall, we did not find clear relationships between antihypertensive medication use and ovarian cancer mortality. However, given the limitation of the data, we cannot determine whether the association may differ by type of beta-blockers. The reasons underlying the observed associations with pre-diagnostic calcium-channel blocker use and post-diagnostic ACE inhibitor use require further investigation.

A narrative review on the interaction between genes and the treatment of hypertension and breast cancer

Objective

The aim to discuss the close relationship between the common biological mechanisms of breast cancer and hypertension, inflammation and oxidative stress, breast cancer gene mutations breast cancer susceptibility gene (BRCA), G protein-coupled receptor kinase (GRK4), etc. and breast cancer treatment includes chemotherapy, Endocrine therapy, Targeted therapy and anti-angiogenesis drugs. In anti-angiogenesis drugs focusing on the mechanism of tyrosine kinase inhibitors (TKI) that may activate the rhoa/rock pathway to cause hypertension, as well as the relationship between breast cancer and antihypertensive drugs includes angiotensin-converting enzyme inhibitors (ACEIs), Calcium channel blockers (CCBs) and β-blockers (BBs)will be explored.

Background

Cardiovascular diseases (CVD) and tumors are the two major types of diseases with the highest mortality rates, while hypertension accounts for the largest proportion of CVDs. A large number of the same or similar risk factors are shared between hypertension and tumors, and they influence each other. Many patients, particularly elderly patients, often present with the coexistence of the two diseases. As medical advances have enabled clinicians to cure tumors, many patients with cancer live longer, leading to a gradual increase in the incidence of CVDs, including hypertension. With the second highest incidence among tumors, breast cancer has gradually attracted widespread attention and has been the topic of numerous studies. Studies have confirmed that CVD is one of the causes of death in elderly patients with breast cancer.

Methods

Publications from 1985 to 2020 were retrieved from the Web Of Science, Cochrane Library, PubMed, EMBASE and MEDLINE database. We used a mix of MeSH and keywords.

Conclusions

Hypertension and cancer may share a common mechanism. The screening and risk assessment of breast cancer in patients with hypertension must be strengthened. Breast cancer cardiology is the interdisciplinary study of oncology and cardiology, and in-depth research in this field may result in long-term improvements in the survival and prognosis of patients with both clinical hypertension and breast cancer.

Light-controlled calcium signalling in prostate cancer and benign prostatic hyperplasia

Background

Identifying ways to reduce the burden of prostate cancer (Pca) or benign prostatic hyperplasia (BPH) is a top research priority. It is a typical entanglement seen in men which is portrayed by trouble in micturition. It stands as a significant problem in our society. Different molecular biomarker has high potential to treat Pca or BPH but also causes serious side effects during treatment.

Main text

The role of calcium signalling in the alteration of different biomarkers of Pca or BPH is important. Therefore, the photoswitch drugs may hold the potential to rebalance the altered calcium signaling cascade and the biomarker levels. Thereby play a significant role in the management of Pca and BPH. Online literature searches such as PubMed, Web of Science, Scopus, and Google Scholar were carried out. The search terms used for this review were photo-pharmacology, photo-switch drug, photodynamic therapy, calcium signalling, etc. Present treatment of Pca or BPH shows absence of selectivity and explicitness which may additionally result in side effects. The new condition of the calcium flagging may offer promising outcomes in restoring the present issues related with prostate malignancy and BPH treatment.

Conclusion

The light-switching calcium channel blockers aim to solve this issue by incorporating photo-switchable calcium channel blockers that may control the signalling pathway related to proliferation and metastasis in prostate cancer without any side effects.

Graphical abstract

Schematic diagram explaining the proposed role of photo-switch therapy in curbing the side effects of active drugs in Pca (prostate cancer) and BPH (benign prostatic hyperplasia). a) Delivery of medication by ordinary strategies and irreversible phototherapy causes side effects during treatment. Utilization of photo-switch drug to control the dynamic and inert condition of the medication can cause the medication impacts as we required in prostate cancer and BPH. b) Support of harmony between the calcium signaling is essential to guarantee ordinary physiology. Increment or abatement in the dimensions of calcium signaling can result in changed physiology. c) Major factors involved in the pathogenesis of BPH; downregulation of vitamin D receptor (VDR) and histone deacetylase (HDAC) can prevent BPH. Similarly, downregulation of α-1 adrenoceptor can reduce muscle contraction, while overexpression of β-3 adrenoceptor in BPH can promote further muscle relaxation in BPH treatment therapy. Inhibition of overexpressed biomarkers in BPH TRPM2-1: transient receptor potential cation channel subfamily M member 1; TRPM2-2: transient receptor potential cation channel subfamily M member 2; Androgens; CXCL5: C-X-C motif chemokine ligand 5; TGFβ-1: transforming growth factor β-1; TXA2; thromboxane-2; NMDA: N-methyl-d-aspartate can be the potential target in BPH therapy.

Comparison of the Apoptotic Effects of Topically Applied Papaverine, Diltiazem, and Nitroprusside to Internal Thoracic Artery

Objective

To detect and to compare the apoptotic effects of intraoperatively topically applied diltiazem, papaverine, and nitroprusside.

Methods

Internal thoracic artery segments of ten patients were obtained during coronary bypass grafting surgery. Each internal thoracic artery segment was divided into four pieces and immersed into four different solutions containing separately saline (Group S), diltiazem (Group D), papaverine (Group P), and nitroprusside (Group N). Each segment was examined with both hematoxylin-eosin and the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method in order to determine and quantify apoptosis.

Results

Apoptotic cells were counted in 50 microscopic areas of each segment. No significant difference was observed among the four groups according to hematoxylin-eosin staining. However, the TUNEL method revealed a significant increase in mean apoptotic cells in the diltiazem group when compared with the other three groups (Group S=4.25±1.4; Group D=13.31±2.8; Group N=9.48±2.09; Group P=10.75±2.37). The differences between groups were significant (P=0.0001). No difference was observed between the samples of the diabetic and non-diabetic patients in any of the study groups.

Conclusion

The benefit of topically applied vasodilator drugs must outweigh the potential adverse effects. In terms of apoptosis, diltiazem was found to have the most deleterious effects on internal thoracic artery graft segments. Of the analyzed medical agents, nitroprusside was found to have the least apoptotic activity, followed by papaverine. Diabetes did not have significant effect on the occurrence of apoptosis in left internal thoracic artery grafts.

Diltiazem potentiates the cytotoxicity of gemcitabine and 5-fluorouracil in PANC-1 human pancreatic cancer cells through inhibition of P-glycoprotein

AIM

Pancreatic cancer (PC) is one of the most aggressive tumors with dismal survival and a high death rate due to chemotherapeutic failure. P-glycoprotein (P-gp) plays a pivotal role in PC response to gemcitabine and 5-fluorouracil (5-FU). Diltiazem, a calcium channel blocker, is a P-gp inhibitor. In the current study, we investigated the hypothesis that targeting of P-gp by diltiazem can enhance the cytotoxicity of gemcitabine and 5-FU against human pancreatic cancer cells.

MAIN METHODS

The cytotoxic effect of diltiazem, gemcitabine, and 5-FU in single and combined forms against PANC-1 and AsPC-1 cells were assayed by MTT. Flow cytometric analysis was used for the determination of cell cycle, apoptosis, and stemness markers in PC cells. Besides, immunoblotting was used for assessment of Bax, caspase 3, cyclin D1, and P-gp expressions.

KEY FINDINGS

Diltiazem co-treatment, either with gemcitabine or 5-FU, synergistically reduced cell viability, induced apoptosis, and caused cell cycle arrest. In addition, diltiazem co-treatment decreased the expressions of stem cell markers CD24 and CD44, increased the expressions of Bax and cleaved caspase 3, enhanced DNA fragmentation, and attenuated cyclin D1 and P-gp expressions as compared to cells treated with either gemcitabine or 5-FU alone.

SIGNIFICANCE

Our findings suggest that diltiazem may be potential neoadjuvant therapy to enhance the response of PC to gemcitabine or 5-FU treatment.

Calcium Channel Blockers Impair the Antitumor Activity of Anti-CD20 Monoclonal Antibodies by Blocking EGR-1 Induction

Direct cell death induction, in addition to immune-effector cell-mediated mechanisms, is one of the key mechanisms of action of anti-CD20 antibodies, and yet the signaling pathways implicated remain poorly investigated. Here we show that the transcription factor EGR-1 is rapidly induced by anti-CD20 antibodies and is a key mediator for CD20-induced cell death. EGR-1 induction results from an increased calcium influx induced by anti-CD20 antibodies. We show that both rituximab and obinutuzumab induce calcium influx, albeit through different mechanisms, and this influx is crucial for cell death induction. Inhibition of the calcium flux with calcium channel blockers (CCB) abolished EGR-1 induction and impaired the efficacy of anti-CD20 antibodies in preclinical in vitro and in vivo models. Finally, we investigated the impact of CCBs in patients treated with anti-CD20 antibodies included in the clinical trials GOYA and REMARC, and found that patients simultaneously receiving CCBs and anti-CD20 therapy have a shorter progression-free survival and overall survival. These results reveal EGR-1 as a key mediator of the direct cytotoxic activity of anti-CD20 antibodies and provide a rationale to evaluate EGR-1 expression as a new biomarker to predict response to anti-CD20 treatment. In addition, our findings show that calcium influx is required for anti-CD20-mediated tumor cell death and suggest that simultaneous administration of calcium channel blocking agents could be deleterious in patients receiving anti-CD20-based immunotherapy.

Effects of Covalent Conjugates of Fullerene Derivatives with Xanthene Dyes on Activity of Ca2+-ATPase of the Sarcoplasmic Reticulum

The effects of the newly synthesized covalent conjugates of water-soluble fullerene derivatives (WSFD) with xanthene dyes: polyanionic WSFD-fluorescein (1), polycationic WSFD-fluorescein (2), polyanionic WSFD-eosin (3), and polyanionic WSFD (4), polycationic WSFD (5), fluorescein (6) and eosin (7), on activity of the membrane-bound Ca²⁺-ATPase of the sarcoplasmic reticulum (SR Ca²⁺-ATPase) were studied. Compounds 1, 3, 4, 6, and 7 inhibit the hydrolytic function of the enzyme, the inhibition constants for these compounds are Ki=1.3×10^-5 M (1), Ki=4.7×10^-6 M (3), Ki=2.5×10^-6 M (4), Ki=6.1×10^-5 M (6), and Ki=5.8×10^-6 M (7). The effects of compounds 3, 6, and 7 on the hydrolytic function of the enzyme is competitive; compounds 1 and 4 are noncompetitive. Polycationic WSFD fluorescein (2) and polycationic WSFD (5) do not affect ATP hydrolysis, but inhibit active Ca²⁺ transport in a concentration of 0.01 mM by 100±10 and 40±4%, respectively. Conjugates 1 and 3 completely inhibit the hydrolytic and transport functions of the enzyme in a concentration of 0.01 mM, and in a concentration of 0.001 mM inhibit active Ca²⁺ transport by 60±6 and 55±6% uncoupling the hydrolytic and transport functions of SR Ca²⁺-ATPases. The obtained results demonstrate a significant effect of the studied compounds on the active transmembrane transfer of Ca²⁺ and make it possible to predict the presence of antimetastatic and antiaggregatory activities of the studied compounds.

New drugs are not enough‑drug repositioning in oncology: An update

Drug repositioning refers to the concept of discovering novel clinical benefits of drugs that are already known for use treating other diseases. The advantages of this are that several important drug characteristics are already established (including efficacy, pharmacokinetics, pharmacodynamics and toxicity), making the process of research for a putative drug quicker and less costly. Drug repositioning in oncology has received extensive focus. The present review summarizes the most prominent examples of drug repositioning for the treatment of cancer, taking into consideration their primary use, proposed anticancer mechanisms and current development status.

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.

Dantrolene Attenuates Cardiotoxicity of Doxorubicin Without Reducing its Antitumor Efficacy in a Breast Cancer Model

Dysregulation of calcium homeostasis is a major mechanism of doxorubicin (DOX)-induced cardiotoxicity. Treatment with DOX causes activation of sarcoplasmic reticulum (SR) ryanodine receptor (RYR) and rapid release of Ca²⁺ in the cytoplasm resulting in depression of myocardial function. The aim of this study was to examine the effect of dantrolene (DNT) a RYR blocker on both the cardiotoxicity and antitumor activity of DOX in a rat model of breast cancer. Female F344 rats with implanted MAT B III breast cancer cells were randomized to receive intraperitoneal DOX twice per week (12 mg/kg total dose), 5 mg/kg/day oral DNT or a combination of DOX + DNT for 3 weeks. Echocardiography and blood troponin I levels were used to measure myocardial injury. Hearts and tumors were evaluated for histopathological alterations. Blood glutathione was assessed as a measure of oxidative stress. The results showed that DNT improved DOX-induced alterations in the echocardiographic parameters by 50%. Histopathologic analysis of hearts showed reduced DOX induced cardiotoxicity in the group treated with DOX + DNT as shown by reduced interstitial edema, cytoplasmic vacuolization, and myofibrillar disruption, compared with DOX-only–treated hearts. Rats treated with DNT lost less body weight, had higher blood GSH levels and lower troponin I levels than DOX-treated rats. These data indicate that DNT is able to provide protection against DOX cardiotoxicity without reducing its antitumor activity. Further studies are needed to determine the optimal dosing of DNT and DOX in a tumor-bearing host.

Drug Repurposing for Retinoblastoma: Recent Advances

Retinoblastoma is the intraocular malignancy that occurs during early childhood. The current standard of care includes chemotherapy followed by focal consolidative therapies, and enucleation. Unfortunately, these are associated with many side and late effects. New drugs and/or drug combinations need to be developed for safe and effective treatment. This compelling need stimulated efforts to explore drug repurposing for retinoblastoma. While conventional drug development is a lengthy and expensive process, drug repurposing is a faster, alternate approach, where an existing drug, not meant for treating cancer, can be repurposed to treat retinoblastoma. The present article reviews various attempts to test drugs approved for different purposes such as calcium channels blockers, non-steroidal antiinflammatory drugs, cardenolides, antidiabetic, antibiotics and antimalarial for treating retinoblastoma. It also discusses other promising candidates that could be explored for repurposing for retinoblastoma.

Manoalide Preferentially Provides Antiproliferation of Oral Cancer Cells by Oxidative Stress-Mediated Apoptosis and DNA Damage

Marine sponge-derived manoalide has a potent anti-inflammatory effect, but its potential application as an anti-cancer drug has not yet been extensively investigated. The purpose of this study is to evaluate the antiproliferative effects of manoalide on oral cancer cells. MTS assay at 24 h showed that manoalide inhibited the proliferation of six types of oral cancer cell lines (SCC9, HSC3, OC2, OECM-1, Ca9-22, and CAL 27) but did not affect the proliferation of normal oral cell line (human gingival fibroblasts (HGF-1)). Manoalide also inhibits the ATP production from 3D sphere formation of Ca9-22 and CAL 27 cells. Mechanically, manoalide induces subG1 accumulation in oral cancer cells. Manoalide also induces more annexin V expression in oral cancer Ca9-22 and CAL 27 cells than that of HGF-1 cells. Manoalide induces activation of caspase 3 (Cas 3), which is a hallmark of apoptosis in oral cancer cells, Ca9-22 and CAL 27. Inhibitors of Cas 8 and Cas 9 suppress manoalide-induced Cas 3 activation. Manoalide induces higher reactive oxygen species (ROS) productions in Ca9-22 and CAL 27 cells than in HGF-1 cells. This oxidative stress induction by manoalide is further supported by mitochondrial superoxide (MitoSOX) production and mitochondrial membrane potential (MitoMP) destruction in oral cancer cells. Subsequently, manoalide-induced oxidative stress leads to DNA damages, such as γH2AX and 8-oxo-2’-deoxyguanosine (8-oxodG), in oral cancer cells. Effects, such as enhanced antiproliferation, apoptosis, oxidative stress, and DNA damage, in manoalide-treated oral cancer cells were suppressed by inhibitors of oxidative stress or apoptosis, or both, such as N-acetylcysteine (NAC) and Z-VAD-FMK (Z-VAD). Moreover, mitochondria-targeted superoxide inhibitor MitoTEMPO suppresses manoalide-induced MitoSOX generation and γH2AX/8-oxodG DNA damages. This study validates the preferential antiproliferation effect of manoalide and explores the oxidative stress-dependent mechanisms in anti-oral cancer treatment.

Anti-Cancer Agents in Proliferation and Cell Death: The Calcium Connection

Calcium (Ca2+) signaling and the modulation of intracellular calcium ([Ca2+]i) levels play critical roles in several key processes that regulate cellular survival, growth, differentiation, metabolism, and death in normal cells. On the other hand, aberrant Ca2+-signaling and loss of [Ca2+]i homeostasis contributes to tumor initiation proliferation, angiogenesis, and other key processes that support tumor progression in several different cancers. Currently, chemically and functionally distinct drugs are used as chemotherapeutic agents in the treatment and management of cancer among which certain anti-cancer drugs reportedly suppress pro-survival signals and activate pro-apoptotic signaling through modulation of Ca2+-signaling-dependent mechanisms. Most importantly, the modulation of [Ca2+]i levels via the endoplasmic reticulum-mitochondrial axis and corresponding action of channels and pumps within the plasma membrane play an important role in the survival and death of cancer cells. The endoplasmic reticulum-mitochondrial axis is of prime importance when considering Ca2+-signaling-dependent anti-cancer drug targets. This review discusses how calcium signaling is targeted by anti-cancer drugs and highlights the role of calcium signaling in epigenetic modification and the Warburg effect in tumorigenesis.

Bladder cancer risk in users of selected drugs for cardiovascular disease prevention

The aim of this study was to investigate the relation between bladder cancer risk and the use of selected drugs for cardiovascular disease (CVD) prevention, such as aspirin, statins, and calcium channel blockers (CCBs). We analyzed data from a multicentric case-control study carried out in Italy between 2003 and 2014, including 690 bladder cancer cases and 665 hospital controls. Odds ratios (ORs) of bladder cancer and corresponding 95% confidence intervals (CIs) were estimated using unconditional multiple logistic regression models. The ORs for bladder cancer were 1.21 (95% CI: 0.87-1.68) for regular use of aspirin, 0.72 (95% CI: 0.54-0.97) for use of any CCBs, and 1.32 (95% CI: 0.87-1.99) for use of any statins. A slight inverse association was found with duration of use of CCBs, whereas no consistent association was found with duration of use, age at first use, and frequency for aspirin and statin use, or with indication of use for aspirin (as an analgesic or, for CVD prevention). No significant association was found for various combinations of drugs or for all drugs combined (OR=1.23, 95% CI: 0.31-4.85). Our data indicate the lack of a relevant association between the use of selected drugs for CVD prevention and bladder cancer risk, although suggest a potential favorable role for CCBs.

Post-diagnosis use of antihypertensive medications and the risk of death from ovarian cancer

OBJECTIVE

To examine associations between post-diagnosis use of antihypertensive (AH) medications including thiazide diuretics (TDs), angiotensin converting enzyme inhibitors (ACEIs), beta blockers (BBs) [both non-selective (NSBBs) and selective (SBBs)] and calcium channel blockers (CCBs) and ovarian cancer-specific survival.

METHODS

This cohort study used SEER-Medicare data on 2195 women 66+ years of age who were diagnosed with ovarian cancer during 2007-2012 and who survived for at least 12 months. Use of an AH class was defined as two or more fills during the year after diagnosis. Ovarian cancer-specific death was assessed starting one year after diagnosis and continued through the end of 2013. Associations between AH use and ovarian cancer-specific mortality were assessed using Cox proportional hazard models, comparing users of a given class of AH to non-AH users.

RESULTS

Overall, 718 (33%), 690 (31%), 521 (24%), 154 (7%) of women used a TD, ACEI, BB, or CCB, respectively, with some women (48%) using more than one class of drug. Ovarian cancer-specific mortality was found to be lower among women who used an ACEI (adjusted hazard ratio [aHR] 0.76, 95% confidence interval [CI] 0.63-0.92), a TD (aHR 0.82, 95%CI 0.68-0.99), or a NSBB (aHR 0.60, 95%CI 0.43-0.83), but no such association was seen in women who took a SBB or CCB.

CONCLUSION

We observed that women who took certain forms of an AH medication during the year following a diagnosis of ovarian cancer were thereafter at a relatively reduced risk of dying from their disease. However, the potential for residual confounding by disease severity argues for a cautious interpretation.

Postdiagnostic Calcium Channel Blocker Use and Breast Cancer Mortality: A Population-based Cohort Study

BACKGROUND

There have long been concerns that calcium channel blockers (CCBs), widely used to treat hypertension, may contribute to malignant growth through the evasion of apoptosis and proliferation of cancer cells. Worryingly, a recent cohort study found breast cancer patients who used CCBs had higher death rates, but interpreting these results was difficult as they were based on all-cause mortality and medication use before cancer diagnosis. We used UK population-based data to more robustly investigate the association between CCB use and cancer-specific mortality.

METHODS

We selected a cohort of patients with breast cancer diagnosed between 1998 and 2012 from English cancer registries. We linked to prescription and clinical records from the Clinical Practice Research Datalink, and to death records from the Office for National Statistics. We used adjusted, time-dependent Cox regression models to calculate hazard ratios (HRs) comparing breast cancer-specific and all-cause mortality between postdiagnostic CCB users and nonusers.

RESULTS

Our cohort included 23,669 breast cancer patients, of whom 5,141 used CCBs and 3,053 died due to their breast cancer during follow-up. After adjustment, CCB users had similar breast cancer-specific mortality to nonusers (HR = 0.98, 95% confidence interval [CI] = 0.88, 1.08). There was no evidence of a dose-response relationship. We found similar associations for specific CCBs, and for all-cause mortality.

CONCLUSIONS

In this large population-based breast cancer cohort, we did not find any evidence that CCB use is associated with increased mortality.

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.

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.

Risk of Breast Cancer With Long-Term Use of Calcium Channel Blockers or Angiotensin-Converting Enzyme Inhibitors Among Older Women

Controversy exists about breast cancer risk associated with long-term use of calcium channel blockers (CCBs) or angiotensin-converting enzyme inhibitors (ACEis), respectively. Our objective in this study was to separately evaluate associations between duration of CCB or ACEi use and breast cancer in hypertensive women aged ≥55 years at 3 sites in the Kaiser Permanente health-care system (1997–2012). Exposures included CCB or ACEi use of 1–12 years’ duration, determined from pharmacy dispensings. Outcomes included invasive lobular or ductal carcinoma. Statistical methods included discrete-time survival analyses. The cohort included 19,674 (17.9%) CCB users and 90,078 (82.1%) ACEi users. Two percent (n = 397) of CCB users and 1.9% (n = 1,733) of ACEi users developed breast cancer. Compared with 1–<2 years of use, in adjusted analysis, there was no association between CCB use for 2–<12 years and breast cancer: All 95% confidence intervals included 1. Increasing duration of ACEi use was associated with reduced breast cancer risk: Compared with 1–<2 years of use, the adjusted hazard ratio was 0.76 (95% confidence interval: 0.63, 0.92) for 5–<6 years of use and 0.63 (95% confidence interval: 0.43, 0.93) for 9–<10 years of use. We conclude that among older women with hypertension, long-term CCB use does not increase breast cancer risk and long-term treatment with ACEis may confer protection against breast cancer.

Long-term use of calcium channel blocking drugs and breast cancer risk in a prospective cohort of US and Puerto Rican women

Background

In a recent case–control study, long-term use of calcium channel blocking drugs was associated with a greater-than-twofold increased breast cancer risk. If prospectively collected data confirm that calcium channel blocker use increases breast cancer risk, this would have major implications for hypertension treatment. The objective of this study was to determine whether women using calcium channel blockers for 10 years or more were at increased risk of developing breast cancer compared with women not using calcium channel blockers.

Methods

The Sister Study is a prospective volunteer cohort study of women from the USA and Puerto Rico designed to evaluate environmental and genetic risk factors for breast cancer. Beginning in 2003, women between the ages of 35 and 74 were recruited. They were eligible to participate if they had a sister with breast cancer but had not been diagnosed with breast cancer themselves. In total, 50,884 women enrolled in the cohort between 2003 and 2009; 50,757 women with relevant baseline data and available follow-up data are included in this study. The exposure of interest is current use of calcium channel blocking drugs and the reported duration of use at entry into the cohort. Secondary exposures of interest were the duration and frequency of use for all other subclasses of antihypertensive drugs. Our main outcome is a self-reported diagnosis of breast cancer during the study follow-up period. With patient permission, self-reported diagnoses were confirmed using medical records.

Results

Results showed 15,817 participants were currently using an antihypertensive drug, and 3316 women were currently using a calcium channel blocker at study baseline; 1965 women reported a breast cancer diagnosis during study follow-up. Using Cox proportional hazards modeling, we found no increased risk of breast cancer among women who had been using calcium channel blockers for 10 years or more compared with never users of calcium channel blockers (HR 0.88, 95 % CI 0.58–1.33).

Conclusions

We saw no evidence of increased risk of breast cancer from 10 years or more of current calcium channel blocker use. Our results do not support avoiding calcium channel blocking drugs in order to reduce breast cancer risk.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-016-0720-6) contains supplementary material, which is available to authorized users.

Angiotensin system inhibitors and survival in patients with metastatic renal cell carcinoma treated with VEGF-targeted therapy: A pooled secondary analysis of clinical trials

Use of angiotensin system inhibitors (ASIs; angiotensin receptor blockers or angiotensin-converting enzyme inhibitors) has been reported to be associated with improved survival in metastatic renal cell carcinoma (mRCC), particularly when used with vascular endothelial growth factor-targeted therapies. This study was a secondary pooled analysis of two Phase III randomized controlled trials (RCTs) of patients with mRCC: NCT00334282 comparing pazopanib to placebo and NCT00720941 comparing pazopanib to sunitinib. ASI users were defined as patients using an ASI at baseline. Association with overall survival (OS; primary outcome) and progression-free survival (PFS) was evaluated using Cox proportional hazards regression. The association was adjusted in multivariable analysis for baseline systolic blood pressure (SBP), use of other antihypertensive drugs and prognostic factors comprising the Heng risk criteria for mRCC. Of 1,545 patients pooled from the two RCTs, 649 (42%) were using one or more antihypertensive drugs at baseline, 385 (59%) of which were using an ASI. In the multivariable analysis of patients using pazopanib or sunitinib, no significant association was observed between baseline ASI use and OS (hazard ratio [HR] 0.97 [95% confidence interval (CI) 0.80-1.18], p = 0.80) or PFS (HR 0.88 [95% CI 0.73-1.06], p = 0.17). Exploratory subgroup analysis of NCT00720941 highlighted that the effect of baseline ASI use on OS may differ between patients treated with sunitinib and pazopanib. In conclusion, use of ASIs at baseline was not a significant independent prognostic factor for improved survival in a pooled analysis of mRCC patients treated with pazopanib or sunitinib.

The role of chemical speciation, chemical fractionation and calcium disruption in manganese-induced developmental toxicity in zebrafish (Danio rerio) embryos

Manganese (Mn) is an essential nutrient that can be toxic in excess concentrations, especially during early development stages. The mechanisms of Mn toxicity is still unclear, and little information is available regarding the role of Mn speciation and fractionation in toxicology. We aimed to investigate the toxic effects of several chemical forms of Mn in embryos of Danio rerio exposed during different development stages, between 2 and 122h post fertilization. We found a stage-specific increase of lethality associated with hatching and removal of the chorion. Mn(II), ([Mn(H2O)6](2+)) appeared to be the most toxic species to embryos exposed for 48h, and Mn(II) citrate was most toxic to embryos exposed for 72 and/or 120h. Manganese toxicity was associated with calcium disruption, manganese speciation and metal fractionation, including bioaccumulation in tissue, granule fractions, organelles and denaturated proteins.

Targeting ion channels for cancer therapy by repurposing the approved drugs

Ion channels have been shown to be involved in oncogenesis and efforts are being poured in to target the ion channels. There are many clinically approved drugs with ion channels as "off" targets. The question is, can these drugs be repurposed to inhibit ion channels for cancer treatment? Repurposing of drugs will not only save investors' money but also result in safer drugs for cancer patients. Advanced bioinformatics techniques and availability of a plethora of open access data on FDA approved drugs for various indications and omics data of large number of cancer types give a ray of hope to look for possibility of repurposing those drugs for cancer treatment. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.

Synthesis and L-type calcium channel blocking activity of new chiral oxadiazolothiazinones

Oxadiazolo[3,4-c][1,4]thiazin-3-ones are cardiovascular agents that block L-type calcium channels. Previous data of cardiac and vasorelaxant activity on guinea-pig for several derivatives indicated the two positions ortho to the thiazine's sulphur as crucial for modulating the activity; but these positions are likely susceptible to metabolic biotransformations, as indicated by in silico predictions. We designed new derivatives, and obtained three negative inotropic agents with EC50 in the low nanomolar range, more potent than all the precursors published so far. In particular, benzocondensation at the thiazine ring led to 3a (EC50 = 0.013 μM) and 3b (EC50 = 0.006 μM). Besides negative inotropy, we also observed relaxant activity on nonvascular muscle in the micromolar range. We resolved the new derivatives by chiral chromatography, and determined their absolute configuration by comparing experimental and calculated chiroptical properties (VCD, ECD and ORD): they hold the same absolute configuration-optical rotation relationship, (S)-(+)/(R)-(-). Both cardiac and nonvascular activity are majorly or mostly retained in the R-form for all the compounds, but for the nonvascular activity we observed a strong stereoselectivity for 3a, with the R-form in the nanomolar range (IC50 = 0.020 μM) and 259-fold more potent than the S-one.

The effect of calcium channel blockers on the outcome of acute myeloid leukemia

The effect of calcium channel blockers (CCBs), beta blockers and angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) on the prognosis of patients with acute myeloid leukemia (AML) is largely unknown. We collected data on the use of these medications in 1043 patients with AML, excluding promyelocytic leukemia, diagnosed and treated at M. D. Anderson Cancer Center between 2000 and 2012. Treatment with either amlodipine or diltiazem predicted a worse overall survival (hazard ratio [HR] 1.6, 95% confidence interval [CI] 1.22-2.06, p < 0.0001). There was no difference in survival depending on whether patients were taking beta blockers, ACE inhibitors or ARBs. The effect of CCBs on survival was independent from the National Comprehensive Cancer Network risk classification, age, performance status, response to treatment, year of diagnosis and CD34 levels, assessed by flow cytometry (HR 1.39, 95% CI 1.05-1.80, p = 0.02). Treatment with either amlodipine or diltiazem predicts worse survival in patients with AML independent of known prognostic factors.

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

OBJECTIVE

To investigate the association between calcium channel blockers (CCBs) and increased risk of breast cancer.

METHODS

Using terms related to breast cancer and CCB, we searched PubMed, Embase, and Web of Science for studies on CCB use and the associated risk of breast cancer published before July 2013. Two evaluators independently selected observational studies on the basis of predetermined selection criteria, and 11 studies were included in the meta-analysis. Summary estimates were obtained using fixed-effects or random-effects models as appropriate, and subgroup analyses, sensitivity analyses, and publication bias tests were performed.

RESULTS

Our meta-analysis consisted of 11 studies, including four case-controls, two nested case-controls, and five cohort studies. The odds ratios (ORs) of the association between CCB use and breast cancer were 1.11 (95% confidence interval [CI] 0.93-1.33) overall, 1.04 (95%CI 0.92-1.18) for prospective studies, and 1.33 (95%CI 0.79-2.25) for retrospective studies. There was a positive association between immediate-release CCB use and risk of breast cancer (OR 1.88, 95%CI 1.37-2.60).

CONCLUSIONS

There is no evidence that CCB use is associated with an increased risk of breast cancer. However, there may be a positive association between immediate-release CCB use and risk of breast cancer, but given the current preference for use of sustained-release CCB, the potential clinical impact of this association is limited.

Paclitaxel induces apoptosis in breast cancer cells through different calcium--regulating mechanisms depending on external calcium conditions

Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis.

Use of antihypertensive medications and breast cancer risk among women aged 55 to 74 years

IMPORTANCE

Antihypertensive agents are the most commonly prescribed class of medications in the United States. Evidence regarding the relationship between different types of antihypertensives and breast cancer risk is sparse and inconsistent, and prior studies have lacked the capacity to assess impacts of long-term use.

OBJECTIVE

To evaluate associations between use of various classes of antihypertensive medications and risks of invasive ductal and invasive lobular breast cancers among postmenopausal women.

DESIGN, SETTING, AND PARTICIPANTS

Population-based case-control study in the 3-county Seattle-Puget Sound metropolitan area. Participants were women aged 55 to 74 years, 880 of them with invasive ductal breast cancer, 1027 with invasive lobular breast cancer, and 856 with no cancer serving as controls.

EXPOSURES

Recency and duration of use of antihypertensive medications.

MAIN OUTCOMES AND MEASURES

Risks of invasive ductal and invasive lobular breast cancers.

RESULTS

Current use of calcium-channel blockers for 10 or more years was associated with higher risks of ductal breast cancer (odds ratio [OR], 2.4; 95% CI, 1.2-4.9) (P= .04 for trend) and lobular breast cancer (OR, 2.6; 95% CI, 1.3-5.3) (P= .01 for trend). This relationship did not vary appreciably by type of calcium-channel blocker used (short-acting vs long-acting, dihydropyridines vs non-dihydropyridines). In contrast, use of diuretics, β-blockers, and angiotensin II antagonists were not associated with risk.

CONCLUSIONS AND RELEVANCE

While some studies have suggested a positive association between calcium-channel blocker use and breast cancer risk, this is the first study to observe that long-term current use of calcium-channel blockers in particular are associated with breast cancer risk. Additional research is needed to confirm this finding and to evaluate potential underlying biological mechanisms.

Characterization of cardiac lesions in calves after ingestion of Japanese yew (Taxus cuspidata)

Plants of the genus Taxus are common ornamental shrubs that contain cardiotoxic alkaloids. Gross lesions consistent with heart failure are frequently reported in fatal cases; however, microscopic lesions in the heart have not been well characterized. The current report describes 2 related outbreaks in which 7 of 30, 250-kg calves died after confirmed exposure to clippings of Japanese yew (Taxus cuspidata). Three calves died 24 hr after initial exposure, with no significant gross or histologic lesions. Leaves of the yew plant were identified within the rumen contents, and Taxus alkaloids were confirmed by gas chromatography-mass spectrometry. Following the initial diagnosis, the yew clippings were burned. Two days later, the remaining calves were reintroduced to the enclosure. Within 24 hr, 3 additional calves began to show clinical signs of depression (3/3) or labored breathing (1/3), and by the fourth day, these 3 calves and an additional calf were found dead. Partially burnt yew leaves were found during close inspection of the enclosure. Two of 3 calves submitted for necropsy were severely autolyzed; the third had pulmonary edema and mild fibrinous pleural effusion. Histologic lesions in the latter included multifocal cardiac myocyte hypereosinophilia, sarcolemma fragmentation, pyknosis, karyolysis, myocyte loss, and a mild interstitial lymphoplasmacytic infiltrate with edema. Moderate fibrinosuppurative interstitial pneumonia was the only other significant finding. Cardiac changes were attributed to damage from the initial exposure to Taxus 6 days prior to death.

Growth control in colon epithelial cells: gadolinium enhances calcium-mediated growth regulation

Gadolinium, a member of the lanthanoid family of transition metals, interacts with calcium-binding sites on proteins and other biological molecules. The overall goal of the present investigation was to determine if gadolinium could enhance calcium-induced epithelial cell growth inhibition in the colon. Gadolinium at concentrations as low as 1-5 μM combined with calcium inhibits proliferation of human colonic epithelial cells more effectively than calcium alone. Gadolinium had no detectable effect on calcium-induced differentiation in the same cells based on change in cell morphology, induction of E-cadherin synthesis, and translocation of E-cadherin from the cytosol to the cell surface. When the colon epithelial cells were treated with gadolinium and then exposed to increased calcium concentrations, movement of extracellular calcium into the cell was suppressed. In contrast, gadolinium treatment had no effect on ionomycin-induced release of stored intracellular calcium into the cytoplasm. Whether these in vitro observations can be translated into an approach for reducing abnormal proliferation in the colonic mucosa (including polyp formation) is not known. These results do, however, provide an explanation for our recent findings that a multi-mineral supplement containing all of the naturally occurring lanthanoid metals including gadolinium are more effective than calcium alone in preventing colon polyp formation in mice on a high-fat diet.

Annual fasting plasma glucose variation increases risk of cancer incidence and mortality in patients with type 2 diabetes: the Taichung Diabetes Study

The study aims to examine whether the annual variations in fasting plasma glucose (FPG) measurements, represented by the coefficient of variation (CV), predict cancer incidence and mortality in the subsequent years independent of traditional risk factors of type 2 diabetic patients. A computerized database of patients with type 2 diabetes of 30 years old and older (n=4805) enrolled in the Diabetes Care Management Program of a medical center before 2006 was analyzed using a time-dependent Cox's proportional hazards regression model. The mortality rates for the first, second, and third tertiles of the first annual FPG-CV were 8.64, 12.71, and 30.82 per 1000 person-years respectively. After adjusting for mean FPG, HbA1c, and other risk factors, the annual FPG-CV was independently associated with cancer incidence, cancer mortality, and cancer incidence or mortality, and the corresponding hazard ratios for the third vs first tertile of the annual FPG-CV were 3.03 (1.98, 4.65), 5.04 (2.32, 10.94), and 2.86 (1.91, 4.29) respectively. The annual variation in FPG was a strong predictor of cancer incidence and mortality in type 2 diabetic patients; therefore, glucose variation may be important in the clinical practice of care management and cancer prevention.

Nifetepimine, a dihydropyrimidone, ensures CD4+ T cell survival in a tumor microenvironment by maneuvering sarco(endo)plasmic reticulum Ca2+ ATPase (SERCA)

Multiple mechanisms have been proposed by which tumors induce T cell apoptosis to circumvent tumor immune-surveillance. Although sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA) have long been known to regulate intracellular Ca(2+) homeostasis, few studies have examined the role of SERCA in processes of T lymphocyte survival and activation. In this context it remains largely unexplored as to how tumors jeopardize SERCA function to disable T cell-mediated anti-tumor immunity. Here, we show that human CD4(+) T cells in the presence of tumor conditions manifested an up-regulation of SERCA3 expression that resulted in development of endoplasmic reticulum stress leading to CD4(+) T cell apoptosis. Prostaglandin E(2) produced by the tumor cell plays a critical role in up-regulating SERCA3 by enhancing the binding of its transcription factor Sp1. Gene manipulation and pharmacological approaches further established that an increase in SERCA expression also resulted in subsequent inhibition of PKCα and -θ and retention of NFκB in the cytosol; however, down-modulation of SERCA3 expression by a dihydropyrimidone derivative, ethyl-4-(3-nitro)-phenyl-6-methyl-2-oxo-1,2,3,4-tetrahydropyrimidine-5 carboxylate (nifetepimine), protected the CD4(+) T cells from tumor-induced apoptosis. In fact, nifetepimine-mediated restoration of PKC activity resulted in nuclear translocation of p65NFκB, thereby ensuring its survival. Studies further undertaken in a tumor-bearing mice model revalidated the immunoprotective role of nifetepimine. Our present study thus strongly suggests that imbalance in cellular calcium homeostasis is an important factor leading to CD4(+) T cell death during cancer and holds promise that nifetepimine may have the potential to be used as an immunorestoring agent in cancer bearers.

Differential effects of alprazolam and clonazepam on the immune system and blood vessels of non-stressed and stressed adult male albino rats

Benzodiazepines belongs to one of the most commonly used anxiolytic and anticonvulsant drugs in the world. Full description of toxic effects on different organs is lacking for nearly all the current benzodiazepines. The aim of the current work was to study the immunologic and vascular changes induced by sub-chronic administration of alprazolam and clonazepam in non-stressed and stressed adult male albino rats. Forty-two adult male albino rats were divided into 6 groups (I): (Ia) Negative control rats, (Ib): Positive control rats received distilled water, (II): Stressed rats, (III): Non-stressed rats received daily oral dose of clonazepam (0.5 mg/kg), (IV): Stressed rats received daily oral dose of clonazepam (0.5 mg/kg), (V): Non-stressed rats received daily oral dose of alprazolam (0.3 mg/kg). (VI): Stressed rats received daily oral dose of alprazolam (0.3 mg/kg). At the end of the 4th week, total leukocyte count (WBCs) and differential count were determined, anti-sheep RBC antibody (Anti-SRBC) titer and interleukin-2 (IL-2) level were assessed, thymus glands, lymph nodes, spleens and abdominal aortae were submitted to histopathological examination. Alprazolam was found to induce a significant increase in neutrophil count and a significant decrease in lymphocytes, anti-SRBC titer and IL-2 level with severe depletion of the splenic, thymal and nodal lymphocytes, accompanied by congestion and eosinophilic vasculitis of all organs tested in comparison to clonazepam treated rats. Stress enhanced the toxic effects. It was concluded that the immune system and blood vessels can be adversely affected to a greater extent by short-term chronic administration of alprazolam than by clonazepam, and these toxic effects are aggravated by stress.

Metabolic factors and the risk of pancreatic cancer: a prospective analysis of almost 580,000 men and women in the Metabolic Syndrome and Cancer Project

BACKGROUND

The aim of this study was to investigate the association between factors in metabolic syndrome (MetS; single and combined) and the risk of pancreatic cancer.

METHODS

The Metabolic Syndrome and Cancer Project is a pooled cohort containing data on body mass index, blood pressure, and blood levels of glucose, cholesterol, and triglycerides. During follow-up, 862 individuals were diagnosed with pancreatic cancer. Cox proportional hazards analysis was used to calculate relative risks (RR) with 95% confidence intervals using the above-mentioned factors categorized into quintiles and transformed into z-scores. All z-scores were summarized and a second z-transformation creating a composite z-score for MetS was done. All risk estimates were calibrated to correct for a regression dilution bias.

RESULTS

The trend over quintiles was positively associated with the risk of pancreatic cancer for mid-blood pressure (mid-BP) and glucose in men and for body mass index, mid-BP, and glucose in women. The z-score for the adjusted mid-BP (RR, 1.10; 1.01-1.20) and the calibrated z-score for glucose (RR, 1.37; 1.14-1.34) were positively associated with pancreatic cancer in men. In women, a positive association was found for calibrated z-scores for mid-BP (RR, 1.34; 1.08-1.66), for the calibrated z-score for glucose (RR, 1.98; 1.41-2.76), and for the composite z-score for MetS (RR, 1.58; 1.34-1.87).

CONCLUSION

Our study adds further evidence to a possible link between abnormal glucose metabolism and risk of pancreatic cancer.

IMPACT

To our knowledge, this is the first study on MetS and pancreatic cancer using prediagnostic measurements of the examined factors.

Verapamil enhances the antitumoral efficacy of oncolytic adenoviruses

The therapeutic potential of oncolytic adenoviruses is limited by the rate of adenovirus release. Based on the observation that several viruses induce cell death and progeny release by disrupting intracellular calcium homeostasis, we hypothesized that the alteration in intracellular calcium concentration induced by verapamil could improve the rate of virus release and spread, eventually enhancing the antitumoral activity of oncolytic adenoviruses. Our results indicate that verapamil substantially enhanced the release of adenovirus from a variety of cell types resulting in an improved cell-to-cell spread and cytotoxicity. Furthermore, the combination of the systemic administration of an oncolytic adenovirus (ICOVIR-5) with verapamil in vivo greatly improved its antitumoral activity in two different tumor xenograft models without affecting the selectivity of this virus. Overall, our findings indicate that verapamil provides a new, safe, and versatile way to improve the antitumoral potency of oncolytic adenoviruses in the clinical setting.