Statins potentiate cytostatic/cytotoxic activity of sorafenib but not sunitinib against tumor cell lines in vitro

Statins and Cancer: A Complex Relationship Worth Exploring

This Special Issue, entitled "Statins and Cancer", aims to demonstrate recent and new advances and future trends in using statins in the field of oncology [...].

Influence of statin use on prognosis of patients with renal cell cancer: a meta-analysis

Background

Statin may confer anticancer efficacy, while the studies evaluating the influence of statin on survival of patients with renal cell cancer (RCC) yielded inconsistent results. A systematic review and meta-analysis was performed to investigate the association between statin use and survival of patients with RCC.

Materials and Methods

Cohort studies were identified by search of PubMed, Embase, and Web of Science databases according to the objective of the meta-analysis. A random-effect model incorporating the possible between-study heterogeneity was used for meta-analysis. Subgroup analyses according to study characteristics were also performed.

Results

Seventeen cohort studies involving 42528 patients with RCC were available for the meta-analysis. Results showed that statin use was associated with a better overall survival (OS, hazard ratio [HR]: 0.73, 95% confidence interval [CI]: 0.65 to 0.84, p < 0.001; I² = 40%), progression progression-free survival (PFS, HR: 0.82, 95% CI: 0.68 to 0.98, p = 0.03; I² = 52%), and cancer-specific survival (CSS, HR: 0.76, 95% CI: 0.59 to 0.99, p = 0.04; I² = 38%). Besides, for the outcome of OS and PFS, subgroup analyses showed similar results in patients with surgical and non-surgical anticancer treatments, and in patients with stage I-III and stage IV RCC (p values for subgroup difference all > 0.05).

Conclusions

Statin use may be associated with improved survival outcomes in patients with RCC. Although prospective clinical studies should be considered to validate these results, these findings suggest that statins may be potential adjuvant therapy for patients with RCC.

Merits of hiPSC-Derived Cardiomyocytes for In Vitro Research and Testing Drug Toxicity

The progress of medical technology and scientific advances in the field of anticancer treatment have increased the survival probabilities and duration of life of patients. However, cancer-therapy-induced cardiac dysfunction remains a clinically salient problem. Effective anticancer therapies may eventually induce cardiomyopathy. To date, several studies have focused on the mechanisms underlying cancer-treatment-related cardiotoxicity. Cardiomyocyte cell lines with no contractile physiological characteristics cannot adequately model “true” human cardiomyocytes. However, applying “true” human cardiomyocytes for research is fraught with many obstacles (e.g., invasiveness of the procedure), and there is a proliferative limitation for rodent primary cultures. Human-induced pluripotent stem-cell-differentiated cardiomyocytes (hiPSC-CMs), which can be produced efficiently, are viable candidates for mimicking human cardiomyocytes in vitro. We successfully performed cardiac differentiation of human iPSCs to obtain hiPSC-CMs. These hiPSC-CMs can be used to investigate the pathophysiological basis and molecular mechanism of cancer-treatment-related cardiotoxicity and to develop novel strategies to prevent and rescue such cardiotoxicity. We propose that hiPSC-CMs can be used as an in vitro drug screening platform to study targeted cancer-therapy-related cardiotoxicity.

Atorvastatin inhibits the proliferation of MKN45-derived gastric cancer stem cells in a mevalonate pathway-independent manner

Gastric cancer stem cells (GCSCs) are a major cause of radioresistance and chemoresistance in gastric cancer (GC). Therefore, targeting GCSCs is regarded as a powerful strategy for the effective treatment of GC. Atorvastatin is a widely prescribed cholesterol-lowering drug that inhibits 3-hydroxy-3-methylglutaryl-coenzyme A reductase, a rate-limiting enzyme in the mevalonate pathway. The anticancer activity of atorvastatin, a repurposed drug, is being investigated; however, its therapeutic effect and molecular mechanism of action against GCSCs remain unknown. In this study, we evaluated the anticancer effects of atorvastatin on MKN45-derived GCSCs. Atorvastatin significantly inhibited the proliferative and tumorsphere-forming abilities of MKN45 GCSCs in a mevalonate pathway-independent manner. Atorvastatin induced cell cycle arrest at the G0/G1 phase and promoted apoptosis by activating the caspase cascade. Furthermore, atorvastatin exerted an antiproliferative effect against MKN45 GCSCs by inhibiting the expression of cancer stemness markers, such as CD133, CD44, integrin α6, aldehyde dehydrogenase 1A1, Oct4, Sox2, and Nanog, through the downregulation of β-catenin, signal transducer and activator of transcription 3, and protein kinase B activities. Additionally, the combined treatment of atorvastatin and sorafenib, a multi-kinase targeted anticancer drug, synergistically suppressed not only the proliferation and tumorsphere formation of MKN45 GCSCs but also the in vivo tumor growth in a chick chorioallantoic membrane model implanted with MKN45 GCSCs. These findings suggest that atorvastatin can therapeutically eliminate GCSCs.

Statins and renal cell carcinoma: Antitumor activity and influence on cancer risk and survival

Statins are commonly prescribed to reduce plasma cholesterol levels and risk of cardiovascular events and mortality. Statin exposure may have cancer-preventive properties in some solid tumors, including Renal Cell Carcinoma (RCC). Emerging evidences show that statins can inhibit RCC cell growth by inducing cell cycle arrest and apoptosis in a dose- and time-dependent manner. In addition, statins inhibit the phosphorylation of AKT, mammalian target of rapamycin (mTOR), and ERK leading to reduced motility of RCC cells. Interestingly, the potential impact of concomitant statin intake has been recently evaluated in RCC patients treated by targeted therapy or immunotherapy. In this review, we illustrate the most recent data on the preclinical activity of statins in Renal Cell Carcinoma models and discuss the impact of their use on the prevention and survival of patients affected by this tumor.

Pharmacological Targeting of Ferroptosis in Cancer Treatment

Ferroptosis is a non-apoptotic mode of Regulated Cell Death (RCD) driven by excessive accumulation of toxic lipid peroxides and iron overload. Ferroptosis could be triggered by inhibiting the antioxidant defense system and accumulating iron-dependent Reactive Oxygen Species (ROS) that react with polyunsaturated fatty acids in abundance. Emerging evidence over the past few years has revealed that ferroptosis is of great potential in inhibiting growth and metastasis and overcoming tumor cell resistance. Thus, targeting this form of cell death could be perceived as a potentially burgeoning approach in cancer treatment. This review briefly presents the underlying mechanisms of ferroptosis and further aims to discuss various types of existing drugs and natural compounds that could be potentially repurposed for targeting ferroptosis in tumor cells. This, in turn, will provide critical perspectives on future studies concerning ferroptosis-based cancer therapy.

Crystallization of the Multi-Receptor Tyrosine Kinase Inhibitor Sorafenib for Controlled Long-Term Drug Delivery Following a Single Injection

Introduction

A major challenge in cancer medicine is the safe and effective delivery of drugs to the right tissue at the right time. Despite being designed for greater target specificity, many drugs still result in side effects and lack of safety in patients following global dissemination. Therefore, to develop new, more effective formulations capable of improving specificity and reducing off-target effects, here we describe formulation of drug crystals, from even a very hydrophobic and otherwise difficult to solubilize small molecule chemical compound, capable of providing constant drug release for weeks following a single injection.

Methods

We chose to utilize the multi-tyrosine kinase inhibitor and multi-modal (anti-angiogenic and tumor cell cytotoxic) agent sorafenib, to combat aberrant angiogenesis and tumor growth which contribute to metastasis, ultimately responsible for poor patient outcomes. We tuned crystal size (surface area:volume ratios), imaged by SEM, to display controllability of drug delivery kinetics in in vitro drug release assays.

Results

Single and powder crystal X-ray diffraction (XRD) established that all crystals were the same polymorph and drug form. When utilized against an orthotopic triple negative breast cancer (TNBC) mouse model (4T1 in syngeneic BALB/c mice), we established anti-tumor activity from a single local, subcutaneous injection of crystalline sorafenib.

Conclusion

From our findings, we support that engineering crystalline drug delivery systems has implications in the treatment of cancer or other diseases where high enough constitutive drug levels are needed to maintain target saturation and inhibition while also preventing emergence of drug resistance, which is a consequence often seen with suboptimal dosing.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12195-021-00708-6.

Sex-Differences in Discontinuation of Statin Treatment in Cancer Patients the Year before Death

Statin treatment is often terminated in patients with advanced cancer but guidelines for statin discontinuation are still lacking. The aim of this study was to investigate sex-differences in time-points of statin discontinuation in patients with advanced cancer. Medical records from 1535 deceased patients enrolled at a Palliative Home Care Unit were reviewed. A total of 149 patients (42 women and 107 men) who were diagnosed with cancer, and were treated with statins one year before death, were identified. Statin treatment was terminated earlier in women than in men, 3.0 months prior to death (IQR 0.88–7.25) as compared to 1.5 months (IQR 0.5–4.0) (p < 0.05), respectively. In a longitudinal analysis there was a significant difference between men and women still on statin treatment at all studied time-points, 9, 6, and 3 months before death (p < 0.05), where women terminated statin treatment earlier in the disease trajectory. Baseline demographics were similar between the sexes except that more men than women had a history of previous cardiovascular events (p < 0.01). However, neither the indication for statin treatment, i.e., primary prevention versus secondary prevention, nor age could explain the sex-difference in statin discontinuation. There was no difference in cardiovascular events or mortality between men and women after statin discontinuation.

Efficacy and Safety of the Combination of Pravastatin and Sorafenib for the Treatment of Advanced Hepatocellular Carcinoma (ESTAHEP Clinical Trial)

Pravastatin has demonstrated anti-tumor activity in preclinical and clinical studies. This multicentric randomized double-blind placebo-controlled phase II study (NCT01418729) investigated the efficacy and safety of sorafenib + pravastatin combination on the overall survival (OS) and time to progression (TTP) of patients with advanced hepatocellular carcinoma (aHCC). A total of 31 patients were randomized. Median OS did not differ between both groups (12.4 months for the sorafenib + pravastatin group vs. 11.6 months for the control group). Of note, however, the radiological TTP was higher in patients treated with sorafenib + pravastatin than in the control group (9.9 months vs. 3.2 months; p = 0.008). Considering all the study population, the presence of portal vein thrombosis (PVT) was associated with worse OS, being lower in patients with PVT compared to patients without PVT (6.3 months vs. 14.8 months; p = 0.026). Data also showed a decrease in OS in patients with vascular invasion (VI) compared to patients who did not present it (6.3 months vs. 14.8 months; p = 0.041). The group of patients without dermatological events (DE) showed lower OS (6.9 months vs. 14.5 months; p = 0.049). In conclusion, combination of sorafenib + pravastatin was safe and well-tolerated, prolonging the TTP of patients with aHCC but not improving the OS compared to sorafenib + placebo. The absence of PVT and VI and the development of DE are positive prognostic factors of sorafenib response.

Pharmacokinetic Interaction between Sorafenib and Atorvastatin, and Sorafenib and Metformin in Rats

The tyrosine kinase inhibitor sorafenib is the first-line treatment for patients with hepatocellular carcinoma (HCC), in which hyperlipidemia and type 2 diabetes mellitus (T2DM) may often coexist. Protein transporters like organic cation (OCT) and multidrug and toxin extrusion (MATE) are involved in the response to sorafenib, as well as in that to the anti-diabetic drug metformin or atorvastatin, used in hyperlipidemia. Changes in the activity of these transporters may lead to pharmacokinetic interactions, which are of clinical significance. The study aimed to assess the sorafenib−metformin and sorafenib−atorvastatin interactions in rats. The rats were divided into five groups (eight animals in each) that received sorafenib and atorvastatin (I_SOR+AT), sorafenib and metformin (II_SOR+MET), sorafenib (III_SOR), atorvastatin (IV_AT), and metformin (V_MET). Atorvastatin significantly increased the maximum plasma concentration (C_max) and the area under the plasma concentration–time curve (AUC) of sorafenib by 134.4% (p < 0.0001) and 66.6% (p < 0.0001), respectively. Sorafenib, in turn, caused a significant increase in the AUC of atorvastatin by 94.0% (p = 0.0038) and its metabolites 2−hydroxy atorvastatin (p = 0.0239) and 4−hydroxy atorvastatin (p = 0.0002) by 55.3% and 209.4%, respectively. Metformin significantly decreased the AUC of sorafenib (p = 0.0065). The AUC ratio (II_SOR+MET group/III_SOR group) for sorafenib was equal to 0.6. Sorafenib did not statistically significantly influence the exposure to metformin. The pharmacokinetic interactions observed in this study may be of clinical relevance in HCC patients with coexistent hyperlipidemia or T2DM.

Therapeutic effect and adverse reaction of sorafenib in the treatment of advanced renal cancer

Efficacy and safety of sorafenib in patients with advanced renal cancer were evaluated. Seventy-four patients with advanced renal cancer treated with sorafenib + interferon from January 2010 to August 2013 were included as the observation group. Another 53 renal cancer patients treated with interferon alone were included in the control group. Clinical data of those patients were retrospectively analyzed. Treatment plan: initial dose was 400 mg, twice a day. Additionally, patients in the interferon group were treated with another 300 MU every other day. Efficacy was evaluated according to RECIST criteria, and progression-free survival (PFS), overall survival (OS), and incidence of adverse reactions were recorded. In the observation group, a median OS was 15.3 months (range, 9–60 months), and a median PFS was 8.2 months (range, 2–36 months). There were 4 cases of complete remission (CR) (5.41%), 16 cases of partial remission (PR) (21.62%), 42 cases of stable disease (SD) (56.76%), 12 cases of disease progression (16.22%), and disease control rate (DCR) was 83.78% (62 cases). In the control group, median OS time was 12.5 months (range, 8–60 months), and the median PFS time was 9.3 months (range, 2–40 months). There were 2 cases of CR (3.77%), 11 cases of PR (20.75%), 20 cases of SD (37.74%), 20 cases of disease progression (37.74%), and DCR was 62.26% (33 cases). Disease control rate in the observation group was significantly higher than that in the control group (P<0.05). Main adverse events in the groups were skin reaction, fever, diarrhea, fatigue, rash, loss of appetite, hypertension, hair loss and liver function abnormality. Sorafenib-based targeted therapy for the treatment of advanced renal cancer has a higher rate of disease control, and the adverse reactions are controllable and tolerable.

Statins: a new approach to combat temozolomide chemoresistance in glioblastoma

Patients with glioblastoma multiforme (GBM) have an average life expectancy of approximately 15 months. Recently, statins have emerged as a potential adjuvant cancer therapy due to their ability to inhibit cell proliferation and induce apoptosis in many types of cancer. The exact mechanisms that mediate the inhibitory actions of statins in cancer cells are largely unknown. The purpose of this proceeding paper is to discuss some of the known anticancer effects of statins, while focusing on GBM therapy that includes adjunct therapy of statins with chemotherapeutic agents.

ERRα suppression enhances the cytotoxicity of the MEK inhibitor trametinib against colon cancer cells

BACKGROUND

ERRα, a constitutive transcription factor that regulates energy metabolism, plays an important role in the progression of various tumours. However, its role in cell survival and proliferation and its implication in targeted therapy in colon cancer remains elusive.

METHODS

The expression of ERRα in colon cancer tissues and cell lines was detected by using western blotting and immunohistochemistry. A wound healing assay and a transwell assay were performed to examine the migration and invasion of the colon cancer cells. A cell viability assay, clonogenic assay, western blot assay and the dual-luciferase reporter assay were employed to study the interaction between trametinib (inhibitor of MEK) and EGF treatment. Flow cytometry, western blotting, quantitative reverse-transcription polymerase chain reaction and xenograft studies were used to identify whether the combination of trametinib and simvastatin had a synergistic effect.

RESULTS

ERRα positively regulated the cell proliferation, migration and invasion of colon cancer cells, and the suppression of ERRα completely reduced the EGF treatment-induced proliferation of colon cancer cells. Further investigation showed that trametinib partially restrained the up-regulation of ERRα induced by the EGF treatment, and ERRα inhibition increased the sensitivity of colon cancer cells to trametinib. At last, we combined trametinib with simvastatin, a common clinically used drug with a new reported function of transcriptional activity inhibition of ERRα, and found that this combination produced a synergistic effect in inhibiting the proliferation and survival of colon cancer cells in vitro as well as in vivo.

CONCLUSIONS

The present data indicated that ERRα acted as an oncogene in colon cancer cells, and the combined targeting of ERRα and MEK might be a promising therapeutic strategy for colon cancer treatment.

Statins use and cancer: an update

After initial concerns regarding the association of statins with increased incidences of cancer and elevated cancer-related mortality, there are now plenty of data on the antitumor, cytostatic and cytotoxic effectiveness of this class of drugs. Here, we present a short review of possible mechanisms of antineoplastic activity obtained from preclinical research and the influence of statins on cancer treatment. In the second part of the article, we focus on the most recent data from observational clinical trials, as well as meta-analyses regarding cancer incidence and mortality in patients treated with statins.

EGFR-PI3K-PDK1 pathway regulates YAP signaling in hepatocellular carcinoma: the mechanism and its implications in targeted therapy

The epidermal growth factor receptor (EGFR) pathway and Hippo signaling play an important role in the carcinogenesis of hepatocellular carcinoma (HCC). However, the crosstalk between these two pathways and its implications in targeted therapy remains unclear. We found that the activated EGFR signaling could bypass RhoA to promote the expression of YAP(Yes-associated protein), the core effector of the Hippo signaling, and its downstream target Cyr61. Further studies indicated that EGFR signaling mainly acted through the PI3K-PDK1 (Phosphoinositide 3-kinase-Phosphoinositide-dependent kinase-1) pathway to activate YAP, but not the AKT and MAPK pathways. While YAP knockdown hardly affected the EGFR signaling. In addition, EGF could promote the proliferation of HCC cells in a YAP-independent manner. Combined targeting of YAP and EGFR signaling by simvastatin and the EGFR signaling inhibitors, including the EGFR tyrosine kinase inhibitor (TKI) gefitinib, the RAF inhibitor sorafenib and the MEK inhibitor trametinib, presented strong synergistic cytotoxicities in HCC cells. Therefore, the EGFR-PI3K-PDK1 pathway could activate the YAP signaling, and the activated EGFR signaling could promote the HCC cell growth in a YAP-independent manner. Combined use of FDA-approved inhibitors to simultaneously target YAP and EGFR signaling presented several promising therapeutic approaches for HCC treatment.

Synergistic chemotherapeutic effect of sorafenib-loaded pullulan-Dox conjugate nanoparticles against murine breast carcinoma

pH-Sensitive pullulan-doxorubicin conjugates encapsulating sorafenib (P-Dox/S) nanoparticles were developed as a synergistic combinatorial delivery system against murine breast carcinoma. The nanoparticles can encapsulate Dox and sorafenib with ultra-high loading capacity (65.34 wt%) through chemical conjugation and physical loading, whereas can remain stable under physiological conditions and gradually release Dox and sorafenib with the decreasing pH. These conjugates can be effectively internalized and clearly suppress 4T1 cell growth in vitro. Furthermore, research data of in vivo animal models revealed that the synergistic combinatorial P-Dox/S nanoparticles heavily accumulated in solid tumor tissue sites to maximize therapeutic efficacy; they also significantly inhibited solid tumor growth, even remarkably reduced solid tumor volume in comparison to the initial volume, and obviously diminished adverse effects. The anti-tumor therapeutic effect obviously outperformed the delivery of combinational chemotherapy of free drugs or single drug-loaded P-Dox nanoparticles at the same concentration. These promising results indicate the high-efficiency synergistic chemotherapeutic effects of these nanoparticles. Combinational chemotherapy using P-Dox/S nanoparticles has important potential in the clinical treatment of malignancy for overcoming drug resistance and heterogeneity.

Additive Anti-Tumor Effects of Lovastatin and Everolimus In Vitro through Simultaneous Inhibition of Signaling Pathways

Background

The mTORC1-inhibitor everolimus shows limited efficacy in treating patients with gastro-entero-pancreatic or pulmonary neuroendocrine tumors (NETs), and poor outcome in patients with malignant pheochromocytoma or hepatic carcinoma. We speculated that any effect may be enhanced by antogonising other signaling pathways.

Methods

Therefore, we tested the effect of lovastatin—known to inhibit both ERK and AKT signaling—and everolimus, separately and in combination, on cell viability and signaling pathways in human midgut (GOT), pancreatic (BON1), and pulmonary (H727) NET, hepatocellular carcinoma (HepG2, Huh7), and mouse pheochromocytoma (MPC, MTT) cell lines.

Results

Lovastatin and everolimus separately significantly reduced cell viability in H727, HepG2, Huh7, MPC and MTT cells at clinically relevant doses (P ≤ 0.05). However, high doses of lovastatin were necessary to affect GOT or BON1 cell viability. Clinically relevant doses of both drugs showed additive anti-tumor effects in H727, HepG2, Huh7, MPC and MTT cells (P ≤ 0.05), but not in BON1 or GOT cells. In all cell lines investigated, lovastatin inhibited EGFR and AKT signaling. Subsequently, combination treatment more strongly inhibited EGFR and AKT signaling than everolimus alone, or at least attenuated everolimus-induced EGFR or AKT activation. Vice versa, everolimus constantly decreased pp70S6K and combination treatment more strongly decreased pp70S6K than lovastatin alone, or attenuated lovastatin-induced p70S6K activation: in BON1 cells lovastatin-induced EGFR inhibition was least pronounced, possibly explaining the low efficacy and consequent absent additive effect.

Conclusion

In summary, clinically relevant doses of lovastatin and everolimus were effective separately and showed additive effects in 5 out of 7 cell lines. Our findings emphasize the importance of targeting several interacting signaling pathways simultaneously when attempting to attenuate tumor growth. However, the variable reactions of the different cell lines highlight the necessity to understand the unique molecular aberrations in any tumor. Nevertheless, this combination seems worthy of being tested in vivo.

Statin use is associated with improved survival in patients undergoing surgery for renal cell carcinoma

PURPOSE

To determine whether statin use at time of surgery is associated with survival following nephrectomy or partial nephrectomy for renal cell carcinoma (RCC). Statins are thought to exhibit a protective effect on cancer incidence and possibly cancer survival in a number of malignancies. To date, no studies have shown an independent association between statin use and mortality in RCC.

METHODS

A retrospective cohort study of 916 patients who underwent radical or partial nephrectomy for RCC from 2000 to 2010 at a single institution was performed. Primary outcomes were overall (OS) and disease-specific survival (DSS). Univariable survival analyses were performed using the Kaplan-Meier and the log-rank methods. Multivariable analysis was performed using a Cox proportional hazards model. The predictive discrimination of the models was assessed using the Harrell c-index.

RESULTS

The median follow-up of the entire cohort was 42.5 months. The 3-year OS estimate was 83.1% (95% CI: 77.6%-87.3%) for statin users and 77.3% (95% CI: 73.7%-80.6%) for nonstatin users (P = 0.53). The 3-year DSS was 90.9% (95% CI: 86.3%-94.0%) for statin users and 83.5% (95% CI: 80.1%-86.3%) for nonstatin users (P = 0.015). After controlling for age, American Society of Anesthesiology class, pT category, pN category, metastatic status, preoperative anemia and corrected hypercalcemia, and blood type, statin use at time of surgery was independently associated with improved OS (hazard ratio = 0.62; 95% CI: 0.43-0.90; P = 0.011) and DSS (hazard ratio = 0.48; 95% CI: 0.28-0.83; P = 0.009). The multivariable model for DSS had excellent predictive discrimination with a c-index of 0.91.

CONCLUSIONS

These data suggest that statin usage at time of surgery is independently associated with improved OS and DSS in patients undergoing surgery for RCC.

Combination of 13-Cis retinoic acid and lovastatin: marked antitumor potential in vivo in a pheochromocytoma allograft model in female athymic nude mice

Currently, there are no reliably effective therapeutic options for metastatic pheochromocytoma (PCC) and paraganglioma. Moreover, there are no therapies that may prevent the onset or progression of tumors in patients with succinate dehydrogenase type B mutations, which are associated with very aggressive tumors. Therefore, we tested the approved and well-tolerated drugs lovastatin and 13-cis-retinoic acid (13cRA) in vitro in an aggressive PCC mouse cell line, mouse tumor tissue-derived (MTT) cells, and in vivo in a PCC allograft nude mouse model, in therapeutically relevant doses. Treatment was started 24 hours before sc tumor cell injection and continued for 30 more days. Tumor sizes were measured from outside by caliper and sizes of viable tumor mass by bioluminescence imaging. Lovastatin showed antiproliferative effects in vitro and led to significantly smaller tumor sizes in vivo compared with vehicle treatment. 13cRA promoted tumor cell growth in vitro and led to significantly larger viable tumor mass and significantly faster increase of viable tumor mass in vivo over time compared with vehicle, lovastatin, and combination treatment. However, when combined with lovastatin, 13cRA enhanced the antiproliferative effect of lovastatin in vivo. The combination-treated mice showed slowest tumor growth of all groups with significantly slower tumor growth compared with the vehicle-treated mice and significantly smaller tumor sizes. Moreover, the combination-treated group displayed the smallest size of viable tumor mass and the slowest increase in viable tumor mass over time of all groups, with a significant difference compared with the vehicle- and 13cRA-treated group. The combination-treated tumors showed highest extent of necrosis, lowest median microvessel density and highest expression of α-smooth muscle actin. The combination of high microvessel density and low α-smooth muscle actin is a predictor of poor prognosis in other tumor entities. Therefore, this drug combination may be a well-tolerated novel therapeutic or preventive option for malignant PCC.

Transferrin targeted core-shell nanomedicine for combinatorial delivery of doxorubicin and sorafenib against hepatocellular carcinoma

Combinatorial drug delivery is an attractive, but challenging requirement of next generation cancer nanomedicines. Here, we report a transferrin-targeted core-shell nanomedicine formed by encapsulating two clinically used single-agent drugs, doxorubicin and sorafenib against liver cancer. Doxorubicin was loaded in poly(vinyl alcohol) nano-core and sorafenib in albumin nano-shell, both formed by a sequential freeze-thaw/coacervation method. While sorafenib from the nano-shell inhibited aberrant oncogenic signaling involved in cell proliferation, doxorubicin from the nano-core evoked DNA intercalation thereby killing >75% of cancer cells. Upon targeting using transferrin ligands, the nanoparticles showed enhanced cellular uptake and synergistic cytotoxicity in ~92% of cells, particularly in iron-deficient microenvironment. Studies using 3D spheroids of liver tumor indicated efficient penetration of targeted core-shell nanoparticles throughout the tissue causing uniform cell killing. Thus, we show that rationally designed core-shell nanoparticles can effectively combine clinically relevant single-agent drugs for exerting synergistic activity against liver cancer.

FROM THE CLINICAL EDITOR

Transferrin-targeted core-shell nanomedicine encapsulating doxorubicin and sorafenib was studied as a drug delivery system against hepatocellular carcinoma, resulting in enhanced and synergistic therapeutic effects, paving the way towards potential future clinical applications of similar techniques.

Inhibition of autophagy potentiates atorvastatin-induced apoptotic cell death in human bladder cancer cells in vitro

Statins are cholesterol reduction agents that exhibit anti-cancer activity in several human cancers. Because autophagy is a crucial survival mechanism for cancer cells under stress conditions, cooperative inhibition of autophagy acts synergistically with other anti-cancer drugs. Thus, this study investigates whether combined treatment of atorvastatin and autophagy inhibitors results in enhancing the cytotoxic effects of atorvastatin, upon human bladder cancer cells, T24 and J82, in vitro. To measure cell viability, we performed the EZ-Cytox cell viability assay. We examined apoptosis by flow cytometry using annexin-V/propidium iodide (PI and western blot using procaspase-3 and poly (ADP-ribose) polymerase (PARP) antibodies. To examine autophagy activation, we evaluated the co-localization of LC3 and LysoTracker by immunocytochemistry, as well as the expression of LC3 and p62/sequestosome-1 (SQSTM1) by western blot. In addition, we assessed the survival and proliferation of T24 and J82 cells by a clonogenic assay. We found that atorvastatin reduced the cell viability of T24 and J82 cells via apoptotic cell death and induced autophagy activation, shown by the co-localization of LC3 and LysoTracker. Moreover, pharmacologic inhibition of autophagy significantly enhanced atorvastatin-induced apoptosis in T24 and J82 cells. In sum, inhibition of autophagy potentiates atorvastatin-induced apoptotic cell death in human bladder cancer cells in vitro, providing a potential therapeutic approach to treat bladder cancer.

The association between statin medication and progression after surgery for localized renal cell carcinoma

PURPOSE

Evidence suggests that statins may influence pathways of renal cell carcinoma proliferation, although to our knowledge no study has examined the influence of statin medications on the progression of renal cell carcinoma in humans.

MATERIALS AND METHODS

We identified 2,608 patients with localized renal cell carcinoma who were treated surgically between 1995 and 2010 at our tertiary referral center. Competing risks Cox proportional hazards models were used to evaluate the relationship between statin use and time to local recurrence or progression (metastases or death from renal cell carcinoma) and overall survival. Statin use was modeled as a time dependent covariate as a sensitivity analysis. Models were adjusted for clinical and demographic features.

RESULTS

Of 2,608 patients 699 (27%) were statin users at surgery. Statin users had similar pathological characteristics compared to nonusers. At a median followup of 36 months there were 247 progression events. Statin use was associated with a 33% reduction in the risk of progression after surgery (HR 0.67, 95% CI 0.47-0.96, p = 0.028) and an 11% reduction in overall mortality that was not significant (HR 0.89, 95% CI 0.71-1.13, p = 0.3). Modeling statin use as a time dependent covariate attenuated the risk reduction in progression to 23% (HR 0.77, p = 0.12) and augmented the risk reduction in overall survival (HR 0.71, p = 0.002).

CONCLUSIONS

In our cohort statin use was associated with a reduced risk of progression and overall mortality, although this effect was sensitive to the method of analysis. If validated in other cohorts, this finding warrants consideration of prospective research on statins in the adjuvant setting.

Statins and cancer: current and future prospects

Statins are inhibitors of 3-hydroxy-methylglutaryl (HMG) CoA reductase. They exhibit effects beyond cholesterol reduction, including anticancer activity. This review presents the effects of statins in vitro and their possible molecular anticancer mechanisms and critically discusses the data regarding the role of statins in cancer prevention. Finally, this review focuses on the use of statins combined with other chemotherapeutics to increase the effectiveness of cancer treatments. Despite rare and inconclusive clinical data, the preclinical results strongly suggest that such combined treatment could be a promising new strategy for the treatment of certain tumor types.

Pharmacological actions of statins: a critical appraisal in the management of cancer

Statins, among the most commonly prescribed drugs worldwide, are cholesterol-lowering agents used to manage and prevent cardiovascular and coronary heart diseases. Recently, a multifaceted action in different physiological and pathological conditions has been also proposed for statins, beyond anti-inflammation and neuroprotection. Statins have been shown to act through cholesterol-dependent and -independent mechanisms and are able to affect several tissue functions and modulate specific signal transduction pathways that could account for statin pleiotropic effects. Typically, statins are prescribed in middle-aged or elderly patients in a therapeutic regimen covering a long life span during which metabolic processes, aging, and concomitant novel diseases, including cancer, could occur. In this context, safety, toxicity, interaction with other drugs, and the state of health have to be taken into account in subjects treated with statins. Some evidence has shown a dichotomous effect of statins with either cancer-inhibiting or -promoting effects. To date, clinical trials failed to demonstrate a reduced cancer occurrence in statin users and no sufficient data are available to define the long-term effects of statin use over a period of 10 years. Moreover, results from clinical trials performed to evaluate the therapeutic efficacy of statins in cancer did not suggest statin use as chemotherapeutic or adjuvant agents. Here, we reviewed the pharmacology of the statins, providing a comprehensive update of the current knowledge of their effects on tissues, biological processes, and pathological conditions, and we dissected the disappointing evidence on the possible future use of statin-based drugs in cancer therapy.

Effect of simvastatin on cetuximab resistance in human colorectal cancer with KRAS mutations

BACKGROUND

Metastatic colorectal cancer (CRC) patients with v-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations are resistant to treatment with cetuximab, a monoclonal antibody that targets the epidermal growth factor receptor. Statins have reported antitumor activity, but it is unknown whether simvastatin can reverse cetuximab resistance in KRAS mutant CRC.

METHODS

Human CRC cell lines with KRAS mutations (LS153, LS174T, DLD1, LoVo, SW403, SW480, SNU175, and LS1034) or with v-raf murine sarcoma viral oncogene homolog B1 (BRAF) mutations (DiFi, SW48, HT29, and RKO) were used to test the effect of cetuximab, simvastatin, and cetuximab plus simvastatin on cell proliferation and apoptosis in vitro. Because BRAF(V600E) mutant may be responsible for cetuximab resistance in KRAS wild-type cells, we measured the growth of xenograft tumors originating from KRAS mutant and BRAF mutant cells in mice treated with cetuximab alone or plus simvastatin (n = 5 mice per treatment group). We used immunoblot assays to study RAS-regulated activation of BRAF protein after simvastatin treatment. All statistical tests were two-sided.

RESULTS

Addition of simvastatin (0.2 μM) to cetuximab (0.03-1.0 μM) reduced cell proliferation of KRAS mutant (P < .001) but not of BRAF mutant CRC cells in vitro. Treatment of KRAS mutant cells with simvastatin reduced BRAF activity and induced apoptosis. Treatment with cetuximab and simvastatin reduced the growth of xenograft tumors originating from KRAS mutant cells compared with cetuximab alone (eg, for tumors originating from DLD1 cells, cetuximab vs cetuximab + simvastatin, mean tumor volume = 49.4 vs 20.2 cm(3), mean difference = 29.2 cm(3), 95% confidence interval = 19.7 to 38.5, P < .001); treatment with cetuximab alone or in combination with simvastatin had no effect on the growth of BRAF mutant tumors.

CONCLUSION

Simvastatin may overcome cetuximab resistance in colon cancer cells with KRAS mutations by modulating BRAF activity and inducing apoptosis.