Epirubicin: is it like doxorubicin in breast cancer? A clinical review

An epirubicin-peptide conjugate with anticancer activity is dependent upon the expression level of the surface transferrin receptor

Epirubicin (EPI) is one of the most widely used anticarcinogens; however, serious side effects, including cardiomyopathy and congestive heart failure, limit its long‑term administration. To overcome this problem, the HAIYPRH peptide ligand was used with EPI in the synthesis of a HAIYPRH‑EPI conjugate. The anticancer activity and cellular uptake of the conjugate were measured and evaluated. The results of the present study indicated that the cytotoxicity of HAIYPRH‑EPI was correlated with the expression of the cell surface transferrin receptor (TfR). The conjugate exerted high cytotoxicity and proapoptotic function when in an LN229 glioma cell line, which overexpresses surface TfR. It was hypothesized that transferrin (Tf) can promote cytotoxicity. Conversely, the conjugate exhibited very low cytotoxicity and proapoptotic function in a U87 glioma cell line, in which surface TfR expression was undetectable. In addition, fluorescence microscopy and flow cytometry methods were used to evaluate cellular uptake, and the results of these methods were consistent with the present hypotheses. The conjugate cellular uptake of the conjugate in LN229 cells was markedly higher compared with that in U87 cells, and it was hypothesized that Tf can enhance the uptake in LN229 cells. The cytotoxicity of HAIYPRH‑EPI was dependent upon the expression of surface TfR. Considering that the majority of cancer cells have high rates of iron uptake and surface TfR is generally overexpressed on cancer cells, it was speculated by the authors that HAIYPRH‑EPI may form part of an effective strategy for increasing the selectivity of EPI for cancer cells, as well as reducing its systemic toxicity. To confirm the hypothesis, the effects of HAIYPRH‑EPI on non‑cancerous cell lines were investigated. A future study will examine the side effects of HAIYPRH‑EPI, using a suitable delivery system in an animal model.

RNF168 cooperates with RNF8 to mediate FOXM1 ubiquitination and degradation in breast cancer epirubicin treatment

The forkhead box M1 (FOXM1) transcription factor has a central role in genotoxic agent response in breast cancer. FOXM1 is regulated at the post-translational level upon DNA damage, but the key mechanism involved remained enigmatic. RNF168 is a ubiquitination E3-ligase involved in DNA damage response. Western blot and gene promoter-reporter analyses showed that the expression level and transcriptional activity of FOXM1 reduced upon RNF168 overexpression and increased with RNF168 depletion by siRNA, suggesting that RNF168 negatively regulates FOXM1 expression. Co-immunoprecipitation studies in MCF-7 cells revealed that RNF168 interacted with FOXM1 and that upon epirubicin treatment FOXM1 downregulation was associated with an increase in RNF168 binding and conjugation to the protein degradation-associated K48-linked polyubiquitin chains. Consistently, RNF168 overexpression resulted in an increase in turnover of FOXM1 in MCF-7 cells treated with the protein synthesis inhibitor cycloheximide. Conversely, RNF168, knockdown significantly enhanced the half-life of FOXM1 in both absence and presence of epirubicin. Using a SUMOylation-defective FOXM1-5x(K>R) mutant, we demonstrated that SUMOylation is required for the recruitment of RNF168 to mediate FOXM1 degradation. In addition, clonogenic assays also showed that RNF168 mediates epirubicin action through targeting FOXM1, as RNF168 could synergise with epirubicin to repress clonal formation in wild-type but not in FOXM1-deficient mouse embryo fibroblasts (MEFs). The physiological relevance of RNF168-mediated FOXM1 repression is further emphasized by the significant inverse correlation between FOXM1 and RNF168 expression in breast cancer patient samples. Moreover, we also obtained evidence that RNF8 recruits RNF168 to FOXM1 upon epirubicin treatment and cooperates with RNF168 to catalyse FOXM1 ubiquitination and degradation. Collectively, these data suggest that RNF168 cooperates with RNF8 to mediate the ubiquitination and degradation of SUMOylated FOXM1 in breast cancer genotoxic response.

Enhanced antitumor activity and attenuated cardiotoxicity of Epirubicin combined with Paeonol against breast cancer

Epirubicin is widely used for the therapy of various breast cancers. However, it has serious adverse side effects, particularly cardiotoxicity, which can cause irreversible damage in patients. Paeonol, an active component from Moutan Cortex, enhances antitumor activity of antineoplastics and reduces toxicities induced by chemotherapeutics. In this study, we investigated the anticancer activity of Paeonol in combination with Epirubicin against breast cancer and the alleviated effect of Paeonol on cardiotoxicity induced by Epirubicin. The apoptosis results and the coefficient of drug interaction values suggested significantly synergistic in combination of Paeonol and Epirubicin to 4T1 and MCF-7 cells. We further examined antitumor activities of Paeonol or/and Epirubicin in vivo in BALB/c mice and found that co-treatment of Paeonol and Epirubicin had a synergistic inhibitory effect on tumor growth and enhanced apoptosis in tumors in vivo compared with Epirubicin alone. Increased apoptosis was associated with the activation of apoptosis-related proteins including PARP, Bax, caspase 3, and inhibition of p38/JNK/ERK MAPKs. Moreover, Paeonol exhibited a mitigative effect on Epirubicin-induced cardiotoxicity through suppressing NF-kB pathway. In conclusion, Paeonol (a) enhanced the antitumor activity of Epirubicin in a synergistic manner against breast cancer cells via inhibiting p38/JNK/ERK MAPKs and (b) alleviated Epirubicin-induced cardiotoxicity by suppressing NF-kB pathway. These findings suggest that combination of Paeonol and Epirubicin is potentially applicable for breast cancer treatment.

OTUB1 inhibits the ubiquitination and degradation of FOXM1 in breast cancer and epirubicin resistance

The forkhead transcription factor FOXM1 has a key role in DNA damage response, and its deregulated overexpression is associated with genotoxic drug resistance in breast cancer. However, little is known about the posttranslational mechanisms by which FOXM1 expression is regulated by genotoxic agents and how they are deregulated in resistant cells. Initial co-immunoprecipitation studies verified previous proteomic analysis finding that the OTUB1 is a novel FOXM1-interacting protein. Western blot analysis showed that both OTUB1 and FOXM1 expression reduced upon genotoxic agent treatment in MCF-7 cells, but remained relatively constant in resistant cells. FOXM1 expression reduced upon OTUB1 depletion by siRNA and increased with OTUB1 overexpression in MCF-7 cells, arguing that OTUB1 positively regulates FOXM1 expression. In agreement, co-immunoprecipitation experiments demonstrated that FOXM1 expression is associated with OTUB1 binding but inversely correlates with conjugation to the protein degradation-associated Lys-48-linked ubiquitin-chains. Overexpression of wild-type (WT) OTUB1, but not the OTUB1(C91S) mutant, disrupted the formation of Lys48-linked ubiquitin-conjugates on FOXM1. Importantly, knockdown of OTUB1 by siRNA resulted in an increase in turnover of FOXM1 in MCF-7 cells treated with the protein synthesis inhibitor cycloheximide, whereas overexpression of WT OTUB1, but not the OTUB1(C91S) mutant, significantly enhances the half-life of FOXM1. In addition, proliferative and clonogenic assays also show that OTUB1 can enhance the proliferative rate and epirubicin resistance through targeting FOXM1, as OTUB1 has little effect on FOXM1-deficient cells. The physiological relevance of the regulation of FOXM1 by OTUB1 is further underscored by the significant correlations between FOXM1 and OTUB1 expression in breast cancer patient samples. Cox-regression survival analysis indicates that OTUB1 overexpression is linked to poorer outcome in particular in patients treated with chemotherapy. Collectively, these data suggest that OTUB1 limits the ubiquitination and degradation of FOXM1 in breast cancer and has a key role in genotoxic agent resistance.

Vinorelbine and epirubicin share common features with polysialic acid and modulate neuronal and glial functions

Polysialic acid (PSA), a large, linear glycan composed of 8 to over 100 α2,8-linked sialic acid residues, modulates development of the nervous system by enhancing cell migration, axon pathfinding, and synaptic targeting and by regulating differentiation of progenitor cells. PSA also functions in developing and adult immune systems and is a signature of many cancers. In this study we identified vinorelbine, a semi-synthetic third generation vinca alkaloid, and epirubicin, an anthracycline and 4'-epimer of doxorubicin, as PSA mimetics. Similar to PSA, vinorelbine and epirubicin bind to the PSA-specific monoclonal antibody 735 and compete with the bacterial analog of PSA, colominic acid in binding to monoclonal antibody 735. Vinorelbine and epirubicin stimulate neurite outgrowth of cerebellar neurons via the neural cell adhesion molecule, via myristoylated alanine-rich C kinase substrate, and via fibroblast growth factor receptor, signaling through Erk pathways. Furthermore, the two compounds enhance process formation of Schwann cells and migration of cerebellar neurons in culture, and reduce migration of astrocytes after injury. These novel results show that the structure and function of PSA can be mimicked by the small organic compounds vinorelbine and epirubicin, thus raising the possibility to re-target drugs used in treatment of cancers to nervous system repair. Vinorelbine and epirubicin, identified as PSA mimetics, enhance, like PSA, neuronal migration, neuritogenesis, and formation of Schwann cell processes, and reduce astrocytic migration. Ablating NCAM, inhibiting fibroblast growth factor (FGFR) receptor, or adding the effector domain of myristoylated alanine-rich C kinase substrate (MARCKS) minimize the vinorelbine and epirubicin effects, indicating that they are true PSA mimetics triggering PSA-mediated functions.

Dexrazoxane protects breast cancer patients with diabetes from chemotherapy-induced cardiotoxicity

BACKGROUND

To evaluate the cardioprotective effect of dexrazoxane (DEX) on chemotherapy in patients with breast cancer with concurrent type 2 diabetes mellitus (DM2).

METHODS

Eighty female patients with breast cancer with DM2 were randomly assigned to receive chemotherapy only or chemotherapy plus DEX. All patients received 80 mg/m epirubicin and 500 mg/m cyclophosphamide by intravenous infusion every 3 weeks for a total of 6 cycles. The group assigned to receive chemotherapy alone received placebo 30 minutes before epirubicin administration. The group assigned to receive chemotherapy plus DEX received 800 mg/m DEX 30 minutes before epirubicin administration. Cardiac function and hematology before and after 6 cycles of chemotherapy were analyzed.

RESULTS

There was no difference in baseline systole or diastole function between the 2 DM2 groups. Patients receiving chemotherapy alone experienced significantly greater reductions in Ea and significantly greater elevations in E/Ea and Tei index in comparison with patients receiving chemotherapy plus DEX. After chemotherapy, superoxide dismutase was significantly reduced, and serum malondialdehyde (MDA) was significantly increased in patients with DM2. Serum superoxide dismutase levels were comparable between the 2 groups before and after chemotherapy, MDA levels were comparable between the 2 groups before chemotherapy, whereas serum MDA was significantly higher after chemotherapy in the chemotherapy alone group in comparison with the group that received DEX.

CONCULSIONS

DEX protects against cardiotoxicity induced by chemotherapy in patients with breast cancer with concurrent DM2.

Mussel-Inspired Protein Nanoparticles Containing Iron(III)-DOPA Complexes for pH-Responsive Drug Delivery

A novel bioinspired strategy for protein nanoparticle (NP) synthesis to achieve pH-responsive drug release exploits the pH-dependent changes in the coordination stoichiometry of iron(III)-3,4-dihydroxyphenylalanine (DOPA) complexes, which play a major cross-linking role in mussel byssal threads. Doxorubicin-loaded polymeric NPs that are based on Fe(III)-DOPA complexation were thus synthesized with a DOPA-modified recombinant mussel adhesive protein through a co-electrospraying process. The release of doxorubicin was found to be predominantly governed by a change in the structure of the Fe(III)-DOPA complexes induced by an acidic pH value. It was also demonstrated that the fabricated NPs exhibited effective cytotoxicity towards cancer cells through efficient cellular uptake and cytosolic release. Therefore, it is anticipated that Fe(III)-DOPA complexation can be successfully utilized as a new design principle for pH-responsive NPs for diverse controlled drug-delivery applications.

Three-dimensional microenvironment confers enhanced sensitivity to doxorubicin by reducing p53-dependent induction of autophagy

Preclinical studies of anticancer drugs are typically performed using cancer cell lines maintained in two-dimensional (2D) cultures, ignoring the influences of the extracellular matrix (ECM) and three-dimensional (3D) microenvironment. In this study, we evaluated the microenvironmental control of human breast cancer cells responses to doxorubicin (DOXO) using the 3D laminin-rich ECM (3D lrECM) cell culture model. Under 3D culture conditions, MCF-7 cells displayed drastic morphological alterations, a decrease in proliferation and elevated sensitivity to DOXO. Interestingly, the chemotherapy-mediated activation of autophagy was compromised in the 3D matrix, suggesting an association between the increased cytotoxicity of DOXO and hindered autophagy induction. Indeed, while chloroquine or ATG5 knockdown potentiated DOXO-induced cell death under the 2D culture conditions, the autophagy inducer rapamycin improved the resistance of 3D-cultured cells to this drug. Moreover, in the monolayer-cultured cells, DOXO treatment led to increases in p53 and DRAM-1 expression, which is a p53-dependent activator of autophagy that functions in response to DNA damage. Conversely, p53 and DRAM-1 expression was impaired in 3D-cultured cells. The knockdown of p53 by shRNA blocked DRAM-1 activation, impaired autophagy induction and sensitized only those cells maintained under 2D conditions to DOXO. In addition, 2D-cultured MDA-MB-231 cells (a p53-mutated breast cancer cell line) not only showed increased sensitivity to DOXO compared with MCF-7 cells but also failed to induce DRAM-1 expression or autophagy. Similar to p53 silencing, DRAM-1 knockdown potentiated DOXO cytotoxicity only in 2D-cultured cells. These results suggest that the 3D tissue microenvironment controls tumor cell sensitivity to DOXO treatment by preventing p53-DRAM-autophagy axis activation.

Schedule-dependent effects of kappa-selenocarrageenan in combination with epirubicin on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) has a relatively higher incidence in many countries of Asia. Globally, HCC has a high fatality rate and short survival. Epirubicin, a doxorubicin analogue, may be administered alone or in combination with other agents to treat primary liver cancer and metastatic diseases. However, the toxic effects of epirubicin to normal tissues and cells have been one of the major obstacles to successful cancer chemotherapy. Here, we investigated the effects of epirubicin in combination with kappa-selenocarrageenan on mice with H22 implanted tumors and HepG-2 cell proliferation, immune organ index, morphology, cell cycle and related protein expressions in vivo and in vitro with sequential drug exposure. The inhibitory rate of tumor growth in vivo was calculated. Drug sensitivity was measured by MTT assay, and the King's principle was used to evaluate the interaction of drug combination. Morphological changes were observed by fluorescent microscopy. Cell cycle changes were analyzed by flow cytometry. Expression of cyclin A, Cdc25A and Cdk2 were detected by Western blotting. In vivo results demonstrated that the inhibitory rate of EPI combined with KSC was higher than that of KSC or EPI alone, and the Q value indicated an additive effect. In addition, KSC could significantly raise the thymus and spleen indices of mice with H22 implanted tumors. In the drug sensitivity assay in vitro, exposure to KSC and EPI simultaneously was more effective than exposure sequentially in HepG-2 cells, while exposure to KSC prior to EPI was more effective than exposure to EPI prior to KSC. Q values showed an additive effect in the simultaneous group and antagonistic effects in the sequential groups. Morphological analysis showed similar results to the drug sensitivity assay. Cell cycle analysis revealed that exposure to KSC or EPI alone arrested the cells in S phase in HepG-2 cells, exposure to KSC and EPI simultaneously caused accumulation in the S phase, an effect caused by either KSC or EPI. Expression of cyclin A, Cdc25A and Cdk2 protein was down-regulated following exposure to KSC and EPI alone or in combination, exposure to KSC and EPI simultaneously resulting in the lowest values. Taken together, our findings suggest that KSC in combination with EPI might have potential as a new therapeutic regimen against HCC.

Enhanced effect of pH-sensitive mixed copolymer micelles for overcoming multidrug resistance of doxorubicin

P-glycoprotein (P-gp) mediated drug efflux has been recognized as a key factor contributing to the multidrug resistance (MDR) in tumor cells. To address this issue, a new pH-sensitive mixed copolymer micelles system composed of hyaluronic acid-g-poly(l-histidine) (HA-PHis) and d-α-tocopheryl polyethylene glycol 2000 (TPGS2k) copolymers was developed to co-deliver doxorubicin (DOX) and TPGS2k into drug-resistant breast cancer MCF-7 cells (MCF-7/ADR). The DOX-loaded HA-PHis/TPGS2k mixed micelles (HPHM/TPGS2k) were characterized to have a unimodal size distribution, high DOX loading content and a pH dependent drug release profile due to the protonation of poly(l-histidine). As compared to HA-PHis micelles (HPHM), the HPHM/TPGS2k showed higher and comparable cytotoxicity against MCF-7/ADR cells and MCF-7 cells, respectively. The enhanced MDR reversal effect was attributed to the higher amount of cellular uptake of HPHM/TPGS2k in MCF-7/ADR cells than HPHM, arising from the inhibition of P-gp mediated drug efflux by TPGS2k. The measurements of P-gp expression level and mitochondrial membrane potential indicate that the blank HPHM/TPGS2k inhibited P-gp activity by reducing mitochondrial membrane potential and depletion of ATP but without inhibition of P-gp expression. In vivo study of micelles in tumor-bearing mice indicate that HPHM/TPGS2k could reach the tumor site more effectively than HPHM. The pH-sensitive mixed micelles system has been demonstrated to be a promising approach for overcoming the MDR.

Effect of sun ginseng potentiation on epirubicin and paclitaxel-induced apoptosis in human cervical cancer cells

Background

Sun ginseng (SG), a specific formulation of quality-controlled red ginseng, contains approximately equal amounts of three major ginsenosides (RK1, Rg3, and Rg5), which reportedly has antitumor-promoting activities in animal models.

Methods

MTT assay was used to assess whether SG can potentiate the anticancer activity of epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells; apoptosis status was analyzed by annexin V-FITC and PI and analyzed by flow cytometry; and apoptosis pathway was studied by analysis of caspase-3, -8, and -9 activation, mitochondrial accumulation of Bax and Bak, and cytochrome c release.

Results

SG remarkably enhances cancer cell death induced by epirubicin or paclitaxel in human cervical adenocarcinoma HeLa cells, human colon cancer SW111C cells, and SW480 cells. Results of the mechanism study highlighted the cooperation between SG and epirubicin or paclitaxel in activating caspase-3 and -9 but not caspase-8. Moreover, SG significantly increased the mitochondrial accumulation of both Bax and Bak triggered by epirubicin or paclitaxel as well as the subsequent release of cytochrome c in the targeted cells.

Conclusion

SG significantly potentiated the anticancer activities of epirubicin and paclitaxel in a synergistic manner. These effects were associated with the increased mitochondrial accumulation of both Bax and Bak that led to an enhanced cytochrome c release, caspase-9/-3 activation, and apoptosis. Treating cancer cells by combining epirubicin and paclitaxel with SG may prove to be a novel strategy for enhancing the efficacy of the two drug types.

Superior outcome after neoadjuvant chemotherapy with docetaxel, anthracycline, and cyclophosphamide versus docetaxel plus cyclophosphamide: results from the NATT trial in triple negative or HER2 positive breast cancer

The purpose of this study is to evaluate the efficacy and safety of docetaxel plus cyclophosphamide(TC) compared with docetaxel, anthracycline, and cyclophosphamide(TEC) in neoadjuvant treatment of triple negative or HER2 positive breast cancer. Eligible breast cancer patients were randomized to receive six cycles of TC or TEC. The primary end point was pathological complete remission (pCR). Secondary end points included safety, clinical response rate, and survival outcome. One hundred and two patients were initially randomized and 96 patients were available for efficacy analysis. 96.9 % patients were treated with epirubicin as an anthracycline agent. pCR rates were 6.8 % (3/45) and 17.6 % (9/51) in TC and TEC group, respectively, P = 0.113. After a mean follow up of 20 (3–36) months, non-anthracycline-containing TC regimen treatment resulted in a worse event free survival (adjusted hazard ratio [HR] 2.42; 95 % CI1.11–5.30) and disease-free survival (HR 2.85; 95 % CI1.21–6.74) compared with TEC regimen, which was more apparent in triple negative subtype. Severe adverse event rates were similar, except that patients treated with TEC had a higher rate of neutropenia and leucopenia. TEC treatment had a superior survival outcome and trend of higher pCR rate compared with TC in this trial setting, especially in triple negative subtype, which deserves further validation.

Risk-stratified patients with resectable soft tissue sarcoma benefit from epirubicin-based adjuvant chemotherapy

As adjuvant chemotherapy (AC) for soft tissue sarcomas is controversial, we performed a retrospective analysis of patients seen at Washington University in St. Louis to evaluate whether it benefited our patient population. Patients were risk-assessed using the Memorial Sloan Kettering Predictive Nomogram (MSKPN). We defined high-risk patients by a MSKPN 4-year postoperative probability of sarcoma-specific death of ≥0.3 and investigated if they benefited from AC. Retrospective review was performed on patients seen between 15 February 1996 and 6 February 2010. A propensity score method in the logistic regression framework was used to model the likelihood of receiving AC. To make causal inference on the effect of AC on survival outcomes, a propensity score inverse probability of treatment weighting approach was applied to survival analysis. Overall, 135 high-grade patients were assessed, 33 were treated with Ifosfamide/Epirubicin (I/Epi) and 102 were non AC patients. The stratified MSKPN risk was not significantly associated with any survival endpoint in the whole cohort, but trended for overall survival (OS) when evaluated against non AC patients. After adjustment for MSKPN risk and other variables, patients not receiving chemotherapy had significantly worse OS, recurrent free survival, and disease-specific survival (DSS) with adjusted hazard ratios of 4.18 (95% CI: 2.22-7.90), 8.96 (95% CI: 3.85-20.83), and 5.42 (95% CI: 2.09-14.06), respectively. In retrospective analyses, risk-stratified patients with soft tissue sarcoma benefited from I/Epi-based AC. Randomized I/Epi versus I/Doxorubicin clinical trials may determine the optimal adjuvant treatment.

Cardiac tolerability of concurrent administration of trastuzumab and anthracycline-based regimen as adjuvant chemotherapy for breast cancer

BACKGROUND

Retrospective analysis suggests that anthracycline-containing regimens may be superior to non-anthracycline-containing regimens in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer. However, both trastuzumab and anthracycline have cardiotoxicity, and it remains unclear how to use trastuzumab in combination with an anthracycline to curtail their cardiotoxicity.

PATIENTS AND METHODS

From 2010 to 2013, we administered weekly (q1w) paclitaxel (wP) followed by 75 mg/m(2) epirubicin, fluorouracil, and cyclophosphamide (FEC) every third week (q3w) and concurrent q1w trastuzumab (H) to 41 patients with HER2-positive breast cancer (H+ group), and wP followed by FEC100 without trastuzumab to 57 patients who were HER2-negative (H- group). We routinely assessed the left ventricular ejection fraction (LVEF) by echocardiography, at the time of initiation, after wP, and after FEC, and compared them between these 2 groups.

RESULTS

LVEF decreased from 63.2 to 60.9% (p = 0.030) in the H+ group and from 63.9 to 61.9% (p = 0.009) in the H- group. These 2 groups showed no significant difference in the reduction rate of LVEF over the period of chemotherapy (0.968 vs. 0.978: NS, p = 0.6457). There was no severe cardiotoxicity or congestive heart failure in either group.

CONCLUSION

Concurrent administration of epirubicin (q3w, 75 mg/m(2)) and trastuzumab showed no less cardiac tolerability in an adjuvant setting.

pH-responsive controlled release of epirubicin from Fe@Si-PW hybrid nanoparticles

An efficient drug delivery system has been fabricated through an electrostatic interaction between epirubicin and H3PW12O40-functionalized silica encapsulated maghemite nanoparticles. The obtained nanoparticles were characterized for morphology, size distribution, drug loading efficiency, drug content and drug release behavior. Our results indicate that the hybrid nanoparticles possess high adsorption capacity for epirubicin (20.6wt.%) and high drug loading efficiency (82.6%). The drug release is greater in acetate buffer (95.8%) as compared to phosphate buffered saline (47.5%). The pH-responsive release of the hybrid drug carrier and high drug loading efficiency are its advantages as a promising carrier.

Long-term, up to 18 months, protective effects of the angiotensin II receptor blocker telmisartan on Epirubin-induced inflammation and oxidative stress assessed by serial strain rate

PURPOSE

The primary objective of the present study was to show the long lasting cardioprotective activity, at different time-points, up to 18 month-follow-up, of telmisartan in preserving the systolic function (assessed as Strain Rate-SR) in cancer patients treated with EPI both in the adjuvant and metastatic setting; the secondary objective was to confirm the correlation of the cardioprotective activity of telmisartan with a reduction of inflammation and oxidative stress induced by EPI.

METHODS

Phase II single blind placebo-controlled randomized trial. Sample size 50 patients per arm: based on a pre-planned interim analysis for early stopping rules, the study was discontinued for ethical reasons at 49 patients. Cardiovascular disease-free patients with cancer at different sites eligible for EPI-based treatment randomized to: telmisartan n = 25 or placebo n = 24. Echocardiography Tissue Doppler imaging (TDI) strain and strain rate was performed, serum levels of proinflammatory cytokines (IL-6, TNF-α) and oxidative stress (reactive oxygen species, ROS) were assessed at baseline, every 100 mg/m(2) EPI dose and at 6-, 12- and 18-month follow-up (FU).

RESULTS

Significant SR peak reduction in both arms was observed at t2 (cumulative dose EPI 200 mg/m(2)) vs t0. Conversely, at t3, t4, 6-, 12- and 18-month FU SR increased towards normal range in the telmisartan arm, while in the placebo arm SR remained significantly lower. Differences between SR changes in the placebo and telmisartan arm were significant from t3 up to 18 month-FU. IL-6 and ROS increased significantly in the placebo arm at t2 but did not change in the telmisartan arm. A significant (p < 0.05) correlation between changes of SR vs IL-6 and ROS was observed.

CONCLUSIONS

Our results suggest that the protective effect of telmisartan is long lasting, probably by ensuring a permanent (at least up to 18-month FU) defense against chronic or late-onset types of anthracycline-induced cardiotoxicity.

Highly synergistic effect of sequential treatment with epigenetic and anticancer drugs to overcome drug resistance in breast cancer cells is mediated via activation of p21 gene expression leading to G2/M cycle arrest

Epigenetic alterations such as aberrant DNA methylation and histone modifications contribute substantially to both the cause and maintenance of drug resistance. These epigenetic changes lead to silencing of tumor suppressor genes involved in key DNA damage-response pathways, making drug-resistant cancer cells nonresponsive to conventional anticancer drug therapies. Our hypothesis is that treating drug-resistant cells with epigenetic drugs could restore the sensitivity to anticancer drugs by reactivating previously silenced genes. To test our hypothesis, we used drug-resistant breast cancer cells (MCF-7/ADR) and two epigenetic drugs that act via different mechanisms--5-aza-2'-deoxycytidine (decitabine, DAC), a demethylating agent, and suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor--in combination with doxorubicin. We show that the sequential treatment of resistant cells, first with an epigenetic drug (DAC), and then with doxorubicin, induces a highly synergistic effect, thus reducing the IC(50) of doxorubicin by several thousand fold. The sequential treatment caused over 90% resistant cells to undergo G2/M cell cycle arrest, determined to be due to upregulation of p21(WAF1/CIP1) expression, which is responsible for cell-cycle regulation. The induction of p21(WAF1/CIP1) correlated well with the depletion of DNA methyltransferase1 (DNMT1), an enzyme that promotes methylation of DNA, suggesting that the p21(WAF1/CIP1) gene may have been methylated and hence is inactive in MCF-7/ADR cells. Microarray analysis shows expression of several tumor suppressor genes and downregulation of tumor promoter genes, particularly in sequentially treated resistant cells. Sequential treatment was found to be significantly more effective than simultaneous treatment, and DAC was more effective than SAHA in overcoming doxorubicin resistance. Synergistic effect with sequential treatment was also seen in drug-sensitive breast cancer cells, but the effect was significantly more pronounced in resistant cells. In conclusion, the sequential treatment of an epigenetic drug in combination with doxorubicin induces a highly synergistic effect that overcomes doxorubicin resistance in breast cancer cells.