Increased cellular accumulation and distribution of amrubicin contribute to its activity in anthracycline-resistant cancer cells

The Novel Triazolonaphthalimide Derivative LSS-11 Synergizes the Anti-Proliferative Effect of Paclitaxel via STAT3-Dependent MDR1 and MRP1 Downregulation in Chemoresistant Lung Cancer Cells

Multidrug resistance (MDR) is a major cause of the inefficacy and poor response to paclitaxel-based chemotherapy. The combination of conventional cytotoxic drugs has been a plausible strategy for overcoming paclitaxel resistance. Herein, we investigated the cytotoxic effects and underlying mechanism of LSS-11, a novel naphthalimide derivative-based topoisomerase inhibitor, in paclitaxel-resistant A549 (A549/T) lung cancer cells. LSS-11 enhanced cell death in A549/T cells by inducing apoptosis through increasing the DR5 protein level and PARP1 cleavage. Importantly, LSS-11 dose-dependently reduced STAT3 phosphorylation and downregulated its target genes MDR1 and MRP1, without affecting P-gp transport function. Chromatin coimmunoprecipitation (ChIP) assay further revealed that LSS-11 hindered the binding of STAT3 to the MDR1 and MRP1 promoters. Additionally, pharmacological inhibition of p-STAT3 by sulforaphane downregulated MDR1 and MRP1, resulting in A549/T cell death by triggering apoptosis. Collectively, our data show that LSS-11 is a potent naphthalimide-based chemosensitizer that could enhance cell death in paclitaxel-resistant lung cancer cells through the DR5/PARP1 pathway and STAT3/MDR1/MRP1 STAT3 inhibition.

Early assessment of the left ventricular function by epirubicin-induced cardiotoxicity in postoperative breast cancer patients

OBJECTIVE

Epirubicin (Epi) is a potent and effective drug for many malignant cancers with serious cardiotoxicity. Therefore, layer-specific two-dimensional speckle tracking echocardiography (2D-STE) was used to evaluate the longitudinal and circumferential systolic function of the left ventricular for the early detection of cardiotoxicity in this retrospective work.

METHODS

Overall, 130 female patients with postoperative breast cancer who did not receive radiotherapy were classified into three groups: Group A (control group, n = 40) without any chemotherapy; Group B (n = 44) administered Epi at 180 ~ 240 mg/m² ; and Group C (n = 46) administered Epi at ≥360 mg/m² . Peak and global systolic longitudinal strains (GLS) in the total and endocardium, mid-myocardium, and epicardium were measured and calculated from apical four-chamber, apical two-chamber, and left ventricular long-axis views, respectively. Peak and global circumferential strains (GCS) in the total and endocardium, mid-myocardium, and epicardium were measured and calculated from mitral annulus, papillary muscle, and apical levels of the short-axis view, respectively.

RESULTS

The total GLS and GLS of the endocardium in every view were significantly reduced in group C compared with both groups A and B (P < .05), but there was no significant difference between groups A and B (P > .05). The GLS of the epicardium and mid-myocardium in groups B and C were not significantly reduced (P > .05). There were no significant differences in the total GCS and layer-specific GCS of endocardium, mid-myocardium, and epicardium among the three groups (P > .05).

CONCLUSIONS

Left ventricular longitudinal systolic dysfunction was detected. Moreover, an impaired endocardium was also detected in an early assessment by layer-specific 2DSTE.

Cardiotoxicity of anthracycline therapy: current perspectives

Anthracyclines, especially doxorubicin and daunorubicin, are the drugs of first choice in the treatment of patients with hematologic malignancies, soft-tissue sarcomas, and solid tumors. Unfortunately, the use of anthracyclines is limited by their dose-dependent and cumulative cardiotoxicity. The molecular mechanism responsible for anthracycline-induced cardiotoxicity remains poorly understood, although experimental and clinical studies have shown that oxidative stress plays the main role. Hence, antioxidant agents, especially dexrazoxane, and also other drug classes (statins, β-blockers) proved to have a beneficial effect in protecting against anthracycline-induced cardiotoxicity. According to previous clinical trials, the major high-risk factors for anthracycline-induced cardiotoxicity are age, body weight, female gender, radiotherapy, and other diseases such as Down syndrome, familial dilated cardiomyopathy, diabetes and hypertension. Consequently, further studies are needed to elucidate the molecular pathogenesis of anthracycline-induced cardiotoxicity and also to discover new cardioprotective agents against anthracycline-induced cardiotoxicity.

Subcellular localization of anthracyclines in cultured rat cardiomyoblasts as possible predictors of cardiotoxicity

In this study, we compared the cellular uptake, intracellular localization and cytotoxicity of two groups of anthracycline derivatives in cultured H9c2(2-1) rat cardiomyoblasts. The first group consisted of doxorubicin (DOX) and two of its derivatives containing a formamidino group (–N = CH–N<) at the C-3′ position with a morpholine (DOXM) or a hexamethyleneimine (DOXH) ring. The second group consisted of daunorubicin (DRB) and its derivatives containing a morpholine (DRBM) or a hexamethyleneimine (DRBH) ring. DOXH and DRBH were taken up by cardiomyoblasts more efficiently than estimated for other tested anthracyclines. The cellular uptakes of DOXM and DRBM were reduced compared to those of the parent compounds. Applied structural modifications of DOX and DRB influenced the subcellular localization of the tested derivatives. DOX and DOXH were localized primarily in nuclei, whereas the other anthracyclines were found in the nuclei and cytoplasm. The percentages of the compounds that accumulated in the nuclei were 80.2 and 54.2 % for DOX and DOXH, respectively. The lowest nuclear accumulation values were observed for DRBM (19.9 %), DRBH (21.9 %) and DOXM (23.7 %). The ability of anthracyclines to accumulate in the nuclei correlated with their DNA binding constants (r = 0.858, P = 0.029). A correlation was found between the accumulation of the tested anthracyclines in the nuclei of cardiomyoblasts and their cardiotoxicity in vivo, which was observed in our previous study. We suggest that cytotoxicity and the anthracycline accumulation level in the nuclei of cultured cardiomyoblasts could be used for early prediction of their cardiotoxicity.

A high throughput flow cytometric assay platform targeting transporter inhibition

This review highlights the concepts, recent applications and limitations of High Throughput Screening (HTS) flow cytometry-based efflux inhibitory assays. This platform has been employed in mammalian and yeast efflux systems leading to the identification of small molecules with transporter inhibitory capabilities. This technology offers the possibility of substrate multiplexing and may promote novel strategies targeting microbial efflux systems. This platform can generate a comprehensive dataset that may support efforts to map the interface between chemistry and transporter biology in a variety of pathogenic systems.

Multi-drug resistance in cancer chemotherapeutics: mechanisms and lab approaches

Multi-drug resistance (MDR) has become the largest obstacle to the success of cancer chemotherapies. The mechanisms of MDR and the approaches to test MDR have been discovered, yet not fully understood. This review covers the in vivo and in vitro approaches for the detection of MDR in the laboratory and the mechanisms of MDR in cancers. This study also envisages the future developments toward the clinical and therapeutic applications of MDR in cancer treatment. Future therapeutics for cancer treatment will likely combine the existing therapies with drugs originated from MDR mechanisms such as anti-cancer stem cell drugs, anti-miRNA drugs or anti-epigenetic drugs. The challenges for the clinical detection of MDR will be to find new biomarkers and to determine new evaluation systems before the drug resistance emerges.

Phase II study of nedaplatin and irinotecan in patients with extensive small-cell lung cancer

BACKGROUND

The standard chemotherapy for Japanese patients with extensive disease of small-cell lung cancer (ED-SCLC) is cisplatin and irinotecan.

METHODS

Patients with untreated ED-SCLC were treated with nedaplatin (NP) at 50 mg/m(2) and irinotecan (CPT) at 50 mg/m(2) on days 1 and 8 every 4 weeks for four cycles.

RESULTS

Twenty-five patients were registered. Nineteen patients were male and six female, with a median age of 64 years (50-79 years). Two patients had a performance status of 2. Nineteen of them were able to receive 4 courses of NP and CPT chemotherapy. Grade 3 or 4 anemia, neutropenia, and thrombocytopenia occurred in 8.0, 68.0, and 36.0 % of patients, respectively. Other grade 3 toxicities were SGOT, hyponatremia, fatigue, vomiting, diarrhea, hypotension, febrile neutropenia, oral hemorrhage, and pneumonia. Grade 4 fatigue occurred in one patient. There was no treatment-related death. The overall response rate was 100 %. The median progression-free and overall survivals were 6.6 and 16.0 months, respectively, and the 2-year survival rate was 28 %.

CONCLUSION

NP with CPT is effective and safe for patients with ED-SCLC.