The hydroxyl epimer of doxorubicin controls the rate of formation of cytotoxic anthracycline-DNA adducts

A Physiologically Based Pharmacokinetic Model to Predict Determinants of Variability in Epirubicin Exposure and Tissue Distribution

BACKGROUND

Epirubicin is an anthracycline antineoplastic drug that is primarily used in combination therapies for the treatment of breast, gastric, lung and ovarian cancers and lymphomas. Epirubicin is administered intravenously (IV) over 3 to 5 min once every 21 days with dosing based on body surface area (BSA; mg/m²). Despite accounting for BSA, marked inter-subject variability in circulating epirubicin plasma concentration has been reported.

METHODS

In vitro experiments were conducted to determine the kinetics of epirubicin glucuronidation by human liver microsomes in the presence and absence of validated UGT2B7 inhibitors. A full physiologically based pharmacokinetic model was built and validated using Simcyp^® (version 19.1, Certara, Princeton, NJ, USA). The model was used to simulate epirubicin exposure in 2000 Sim-Cancer subjects over 158 h following a single intravenous dose of epirubicin. A multivariable linear regression model was built using simulated demographic and enzyme abundance data to determine the key drivers of variability in systemic epirubicin exposure.

RESULTS

Multivariable linear regression modelling demonstrated that variability in simulated systemic epirubicin exposure following intravenous injection was primarily driven by differences in hepatic and renal UGT2B7 expression, plasma albumin concentration, age, BSA, GFR, haematocrit and sex. By accounting for these factors, it was possible to explain 87% of the variability in epirubicin in a simulated cohort of 2000 oncology patients.

CONCLUSIONS

The present study describes the development and evaluation of a full-body PBPK model to assess systemic and individual organ exposure to epirubicin. Variability in epirubicin exposure was primarily driven by hepatic and renal UGT2B7 expression, plasma albumin concentration, age, BSA, GFR, haematocrit and sex.

Selective chemotherapy and imaging of colorectal and breast cancer cells by a modified MUC-1 aptamer conjugated to a poly(ethylene glycol)-dimethacrylate coated Fe3O4–AuNCs nanocomposite

The combination of diagnosis and targeted therapy within a single nanoplatform is one of the remarkable advances in molecular medicine.

TGF-β plays a vital role in triple-negative breast cancer (TNBC) drug-resistance through regulating stemness, EMT and apoptosis

Triple negative breast cancer (TNBC) is the most malignant subtype of breast cancer in which the cell surface lacks usual targets for drug to exhibit its effects. Epirubicin (Epi) is widely used for TNBC, but a substantial number of patients develop Epi resistance that is usually associated with poor prognosis. Transforming growth factor (TGF-β) is a multifunctional cytokine. In recent study, it appears that TGF-β influences the cancer stem cell population, thus, the drug resistance of cancer may also be affected. We used epirubicin to treat MDA-MB-231 (MB-231) cells and found that TGF-β and breast cancer stem cell markers CD44⁺CD24^- were increased and were dose-dependent of epirubicin. We established drug-resistant cell line from parental MB-231 cells by chronic treatment with low-concentration epirubicin. The MB-231/Epi cell line showed relatively slow growth rate with varied morphology. Transwell assay and drug sensitivity assay revealed that the malignant cell behaviors in terms of migration, invasion and epirubicin-resistant properties were markedly increased in the MB-231/Epi cells. Western blot, immunofluorescence assay, and flow cytometry were used to analyze the expression levels of the breast cancer stem cell markers, CD44 and CD24. Mammospheres assay showed that the stemness of MB-231/Epi was increased compared to their parental cells. Interestingly, MB-231/Epi cells showed different expression levels of apoptosis-related markers: Bcl2, Bax; EMT-related markers E-cadherin, N-cadherin and cell cycle-related marker cyclinD1. These genes have all been shown to be regulated by the TGF-β pathway. Taken together, our findings suggest that TGF-β plays a vital role in TNBC epirubicin-resistance through regulating stemness, EMT and apoptosis.

High expression of UBD correlates with epirubicin resistance and indicates poor prognosis in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous subtype of breast cancer that is prone to recurrence and metastasis with worse prognosis. Epirubicin-based chemotherapy is of great importance for patients with TNBC, but resistance to epirubicin severely limits the application of this drug and this has emerged as a major problem in the treatment of TNBC. The ubiquitin protein D (UBD) molecule has often been considered a tumor oncogene, and has been shown to promote the recurrence and metastasis of malignant tumor cells. Since the role of UBD in epirubicin resistance and its prognostic value in TNBC have not been reported, the study reported here was designed to identify the epirubicin-resistance molecule and clarify the related biomarker for TNBC prognosis.

METHODS

UBD plasmid was transfected into MDA-MB-231 cells, and the cells were exposed to epirubicin to observe the ability of UBD in epirubicin resistance. UBD expression was also detected in 78 breast cancer tissues by immunohistochemistry. Statistical methods were used to study the relationship between UBD expression and epirubicin resistance in TNBC treatment. Kaplan-Meier survival analysis was used to determine the correlation between UBD expression and TNBC patients' prognostic parameters.

RESULTS

UBD expression was found increased in breast cancer tissues. Forced UBD expression was found to have a relationship with TNBC epirubicin resistance in vitro. High expression of UBD was found in TNBC, compared with in non-TNBC, and this played a positive role in epirubicin resistance and indicated the poor prognosis of TNBC treatment.

CONCLUSION

UBD may play an important role in epirubicin resistance in TNBC. UBD has the potential to be a novel biomarker in TNBC chemoresistance and may be a promising therapeutic target for TNBC patients.

Animal models in studies of cardiotoxicity side effects from antiblastic drugs in patients and occupational exposed workers

Cardiotoxicity is an important side effect of cytotoxic drugs and may be a risk factor of long-term morbidity for both patients during therapy and also for staff exposed during the phases of manipulation of antiblastic drugs. The mechanism of cardiotoxicity studied in vitro and in vivo essentially concerns the formation of free radicals leading to oxidative stress, with apoptosis of cardiac cells or immunologic reactions, but other mechanisms may play a role in antiblastic-induced cardiotoxicity. Actually, some new cytotoxic drugs like trastuzumab and cyclopentenyl cytosine show cardiotoxic effects. In this report we discuss the different mechanisms of cardiotoxicity induced by antiblastic drugs assessed using animal models.