Anthracyclines induce cardiotoxicity through a shared gene expression response signature.

TOP2 inhibitors (TOP2i) are effective drugs for breast cancer treatment. However, they can cause cardiotoxicity in some women. The most widely used TOP2i include anthracyclines (AC) Doxorubicin (DOX), Daunorubicin (DNR), Epirubicin (EPI), and the anthraquinone Mitoxantrone (MTX). It is unclear whether women would experience the same adverse effects from all drugs in this class, or if specific drugs would be preferable for certain individuals based on their cardiotoxicity risk profile. To investigate this, we studied the effects of treatment of DOX, DNR, EPI, MTX, and an unrelated monoclonal antibody Trastuzumab (TRZ) on iPSC-derived cardiomyocytes (iPSC-CMs) from six healthy females. All TOP2i induce cell death at concentrations observed in cancer patient serum, while TRZ does not. A sub-lethal dose of all TOP2i induces limited cellular stress but affects calcium handling, a function critical for cardiomyocyte contraction. TOP2i induce thousands of gene expression changes over time, giving rise to four distinct gene expression response signatures, denoted as TOP2i early-acute, early-sustained, and late response genes, and non-response genes. There is no drug- or AC-specific signature. TOP2i early response genes are enriched in chromatin regulators, which mediate AC sensitivity across breast cancer patients. However, there is increased transcriptional variability between individuals following AC treatments. To investigate potential genetic effects on response variability, we first identified a reported set of expression quantitative trait loci (eQTLs) uncovered following DOX treatment in iPSC-CMs. Indeed, DOX response eQTLs are enriched in genes that respond to all TOP2i. Next, we identified 38 genes in loci associated with AC toxicity by GWAS or TWAS. Two thirds of the genes that respond to at least one TOP2i, respond to all ACs with the same direction of effect. Our data demonstrate that TOP2i induce thousands of shared gene expression changes in cardiomyocytes, including genes near SNPs associated with inter-individual variation in response to DOX treatment and AC-induced cardiotoxicity.

3-Indolepropionic acid mitigates sub-acute toxicity in the cardiomyocytes of epirubicin-treated female rats.

Epirubicin (EPI) is an effective chemotherapeutic against breast cancer, though EPI-related cardiotoxicity limits its usage. Endogenously derived 3-indolepropionic acid (3-IPA) from tryptophan metabolism is of interest due to its antioxidant capabilities which may have cardioprotective effects. Supplementation with 3-IPA may abate EPI's cardiotoxicity, and herein we studied the possibility of lessening EPI-induced cardiotoxicity in Wistar rats. Experimental rats (n = 30; BW 180-200 g) were randomly distributed in five cohorts (A-E; n = 6 each). Group A (control), Group B (EPI 2.5 mg/mL), and group C (3-IPA 40 mg/kg) while Groups D and E were co-treated with EPI (2.5 mg/mL) together with 3-IPA (D: 20 and E: 40 mg/kg). Following sacrifice, oxidative status, lipid profile, transaminases relevant to cardiac function, and inflammatory biomarkers were analysed. Also, 8-hydroxyl-2'-deoxyguanosine (8-OHdG) and cardiac troponin T (cTnT) levels were assessed using an enzyme-linked immunosorbent assay (ELISA). EPI-initiated increases in cardiotoxicity biomarkers were significantly (p < 0.05) reduced by 3-IPA supplementation. Decreased antioxidant and increases in reactive oxygen and nitrogen species (RONS), 8-OHdG and lipid peroxidation were lessened (p < 0.05) in rat hearts co-treated with 3-IPA. EPI-induced increases in nitric oxide and myeloperoxidase were reduced (p < 0.05) by 3-IPA co-treatment. In addition, 3-IPA reversed EPI-mediated alterations in alanine aminotransferase (ALT), aspartate amino transaminases (AST), lactate dehydrogenase (LDH), cardiac troponin T (cTnT), and serum lipid profile including total cholesterol and triglycerides. Microscopic examination of the cardiac tissues showed that histopathological lesions severity induced by EPI was lesser in 3-IPA co-treated rats. Our findings demonstrate that supplementing endogenously derived 3-IPA can enhance antioxidant protection in the cardiac tissue susceptible to EPI toxicity in female rats. These findings may benefit breast cancer patients undergoing chemotherapy by further validating these experimental data.

TCF12 regulates exosome release from epirubicin-treated CAFs to promote ER+ breast cancer cell chemoresistance.

Cancer-associated fibroblasts (CAFs) are the predominant stromal cells in the microenvironment and play important roles in tumor progression, including chemoresistance. However, the response of CAFs to chemotherapeutics and their effects on chemotherapeutic outcomes are largely unknown. In this study, we showed that epirubicin (EPI) treatment triggered ROS which initiated autophagy in CAFs, TCF12 inhibited autophagy flux and further promoted exosome secretion. Inhibition of EPI-induced reactive oxygen species (ROS) production with N-acetyl-L-cysteine (NAC) or suppression of autophagic initiation with short interfering RNA (siRNA) against ATG5 blunted exosome release from CAFs. Furthermore, exosome secreted from EPI-treated CAFs not only prevented ROS accumulation in CAFs but also upregulated the CXCR4 and c-Myc protein levels in recipient ER+ breast cancer cells, thus promoting EPI resistance of tumor cells. Together, the current study provides novel insights into the role of stressed CAFs in promoting tumor chemoresistance and reveal a new function of TCF12 in regulating autophagy impairment and exosome release.

Epirubicin toxicity in rat's ovary and uterus: A protective role of 3-Indolepropionic acid supplementation.

The "anthracycline, Epirubicin (EPI)," in managing breast cancer, is highly cytotoxic. Tryptophan-derived 3-indolepropionic acid (3-IPA) decreases oxidative damage, and its prospect of alleviating EPI-induced cytotoxicity was examined in rats' hypothalamus-ovary-uterus axis. Female rats: Control, EPI (2.5 mg/kg), 3-IPA alone (40 mg/kg), EPI+3-IPA (2.5 mg/kg + 20 mg/kg), EPI + 3-IPA2 (2.5 mg/kg + 40 mg/kg) were treated for 28 days. Subsequently, reproductive hormones, oxidative and inflammatory stress biomarkers, and tissue histology were examined. 3-IPA prevented EPI-induced decreases in the follicle-stimulating hormone, estradiol, progesterone and prolactin levels. EPI-mediated reduction in antioxidant enzymes, reduced glutathione and total sulfhydryl groups were partially counteracted by 3-IPA co-treatment. Increased oxidative and inflammatory stress biomarkers caused by treatment with EPI alone were lessened by 3-IPA co-treatment. Also, 3-IPA reduced histological damage in the examined tissues. Conclusively, 3-IPA ameliorated biochemical markers and tissue injury caused by EPI treatment alone via an antioxidative and anti-inflammatory mechanism while stabilising serum hormone dynamics.

The Role of Mitochondrial Quality Control in Anthracycline-Induced Cardiotoxicity: From Bench to Bedside.

Cardiotoxicity is the major side effect of anthracyclines (doxorubicin, daunorubicin, epirubicin, and idarubicin), though being the most commonly used chemotherapy drugs and the mainstay of therapy in solid and hematological neoplasms. Advances in the field of cardio-oncology have expanded our understanding of the molecular mechanisms underlying anthracycline-induced cardiotoxicity (AIC). AIC has a complex pathogenesis that includes a variety of aspects such as oxidative stress, autophagy, and inflammation. Emerging evidence has strongly suggested that the loss of mitochondrial quality control (MQC) plays an important role in the progression of AIC. Mitochondria are vital organelles in the cardiomyocytes that serve as the key regulators of reactive oxygen species (ROS) production, energy metabolism, cell death, and calcium buffering. However, as mitochondria are susceptible to damage, the MQC system, including mitochondrial dynamics (fusion/fission), mitophagy, mitochondrial biogenesis, and mitochondrial protein quality control, appears to be crucial in maintaining mitochondrial homeostasis. In this review, we summarize current evidence on the role of MQC in the pathogenesis of AIC and highlight the therapeutic potential of restoring the cardiomyocyte MQC system in the prevention and intervention of AIC.

Structural basis for stabilization of human telomeric G-quadruplex [d-(TTAGGGT)]4 by anticancer drug epirubicin.

Anthracycline anticancer drugs show multiple strategies of action on gene functioning by regulation of telomerase enzyme by apoptotic factors, e.g. ceramide level, p53 activity, bcl-2 protein levels, besides inhibiting DNA/RNA synthesis and topoisomerase-II action. We report binding of epirubicin with G-quadruplex (G4) DNA, [d-(TTAGGGT)]4, comprising human telomeric DNA sequence TTAGGG, using 1H and 31P NMR spectroscopy. Diffusion ordered spectroscopy, sequence selective changes in chemical shift (~0.33 ppm) and line broadening in DNA signals suggest formation of a well-defined complex. Presence of sequential nuclear Overhauser enhancements at all base quartet steps and absence of large downfield shifts in 31P resonances preclude intercalative mode of interaction. Restrained molecular dynamics simulations using AMBER force field incorporating intermolecular drug to DNA interproton distances, involving ring D protons of epirubicin depict external binding close to T1-T2-A3 and G6pT7 sites. Binding induced thermal stabilization of G4 DNA (~36 °C), obtained from imino protons and differential scanning calorimetry, is likely to come in the way of telomerase association with telomeres. The findings pave the way for drug-designing with modifications at ring D and daunosamine sugar.

Poly-(Lactic-co-Glycolic) Acid Nanoparticles for Synergistic Delivery of Epirubicin and Paclitaxel to Human Lung Cancer Cells.

Combination therapy using chemically distinct drugs has appeared as one of the promising strategies to improve anticancer treatment efficiency. In the present investigation, poly-(lactic-co-glycolic) acid (PLGA) nanoparticles electrostatically conjugated with polyethylenimine (PEI)-based co-delivery system for epirubicin and paclitaxel (PLGA-PEI-EPI-PTX NPs) has been developed. The PLGA-PEI-EPI-PTX NPs exhibited a monodispersed size distribution with an average size of 240.93 ± 12.70 nm as measured through DLS and 70.8-145 nm using AFM. The zeta potential of 41.95 ± 0.65 mV from -17.45 ± 2.15 mV further confirmed the colloidal stability and PEI modification on PLGA nanoparticles. Encapsulation and loading efficiency along with in vitro release of drug for nanoparticles were done spectrophotometrically. The FTIR analysis of PLGA-PEI-EPI-PTX NPs revealed the involvement of amide moiety between polymer PLGA and PEI. The effect of nanoparticles on the cell migration was also corroborated through wound healing assay. The MTT assay demonstrated that PLGA-PEI-EPI-PTX NPs exhibited considerable anticancer potential as compared to the naïve drugs. Further, p53 protein expression analysed through western blot showed enhanced expression. This study suggests that combination therapy using PLGA-PEI-EPI-PTX NPs represent a potential approach and could offer clinical benefits in the future for lung cancer patients.

XIAOPI formula promotes breast cancer chemosensitivity via inhibiting CXCL1/HMGB1-mediated autophagy.

XIAOPI formula is a national approved drug prescribed to patients with high breast cancer risk. Previously we demonstrated that XIAOPI formula could inhibit breast cancer metastasis via suppressing CXCL1 expression, and postulated that "autophagy in cancer" might be one of its most core anti-cancer mechanisms. However, whether XIAOPI formula could be simultaneously applied with chemodrugs and their synergistic mechanisms are still remained unknown. In the present study, XIAOPI formula at non-cytotoxic doses could synergistically enhance the chemosensitivity of breast cancer cells MDA-MB-231 and MCF-7. We found that rapamycin-induced autophagy could reduce the chemosensitivity of breast cancer cells to XIAOPI formula, and the autophagy suppression and chemosensitizing activity of this formula was CXCL1-dependent. The evidence came from that XIAOPI formula was associated with a lower expression of CXCL1 combined with either rapamycin or taxol alone. Besides, the inhibitory effect of XIAOPI formula on the LC3-II and ABCG2 signals was weakened following CXCL1 over-expression, whereas P62 upregulation induced by XIAOPI formula was re-declined. A high throughput - qPCR (HT-qPCR) assay identified HMGB1 as the main autophagic target of XIAOPI formula in chemosensitizing breast cancer. and furhter validation suggested XIAOPI formula exerted chemosensitivity mainly via CXCL1/HMGB1 autophagic axis. Finally, we generated both mice and zebrafish xenotransplantation models bearing MDA-MB-231 breast cancer cells, and found that XIAOPI formula safely enhanced in vivo taxol chemosensitivity on breast cancer. Taken together, XIAOPI formula is a potential adjuvant drug via inhibiting CXCL1/HMGB1-mediated autophagy for breast cancer treatment with good safety.

Molecular recognition of 3+1 hybrid human telomeric G-quadruplex DNA d-[AGGG(TTAGGG)3] by anticancer drugs epirubicin and adriamycin leads to thermal stabilization.

Recent reports suggest influence of anti-cancer anthracyclines on telomere dysfunction and their possible interaction with G-quadruplex (G4) DNA as an alternate pathway to apoptosis. We have investigated interaction of epirubicin and adriamycin with G4 DNA [d-AGGG(TTAGGG)3] comprising human telomeric DNA sequence by surface plasmon resonance, absorption, fluorescence, circular dichroism and thermal denaturation. Epirubicin and adriamycin bind with affinity, Kb, = 2.5×105 and 5.2×105M-1, respectively in monomeric form leading to decrease in absorbance, fluorescence quenching and ellipticity changes without any significant shift in absorption emission maxima with corresponding induced thermal stabilization by 13.0 and 11.6°C in K+ rich solution. Na+ ions did not induce any thermal stabilization. Molecular docking confirmed external binding at grooves and loops of G4 DNA involving 4OCH3 of ring D, 9COCH2OH of ring A, 4'OH/H and 3'NH3+ of daunosamine sugar. Thermal stabilization induced by specific interactions is likely to hamper telomere association with telomerase enzyme and contribute to drug-induced apoptosis in cancer cell lines besides causing damage to duplex DNA. The findings pave the way for drug designing in view of immense possibilities of altering substituent groups on anthracyclines for enhancement of efficacy, reduced cell toxicity as well as specificity towards G-quadruplex DNA.

Spectroscopic and cytotoxicity studies on the combined interaction of (-)-epigallocatechin-3-gallate and anthracycline drugs with human serum albumin.

The interactions of (-)-epigallocatechin-3-Gallate (EGCG) and anthracycline drugs (doxorubicin, DOX and epirubicin, EPI) alone or in combination with human serum albumin (HSA) under physiological condition were studied by fluorescence spectroscopy, UV-vis absorption spectroscopy, circular dichroism (CD) spectroscopy, and dynamic light scattering (DLS). The cytotoxic activity of the single drug, combined drugs, and their complexes with HSA against human cervical cancer HeLa cell line was determined by MTT assay. Fluorescence quenching result and difference spectra of UV absorption revealed the formation of static complex between EGCG, DOX, or EPI and HSA. The binding of EGCG with HSA was driven by both enthalpy and entropy while the binding of DOX or EPI was mainly entropy driven. The nature of binding was expounded based on the effect of sodium chloride, tetrabutylammonium bromide, and sucrose which interfere in electrostatic, hydrophobic, and hydrogen bonding interactions, respectively. Site marker competitive experiments combined with synchronous fluorescence spectra showed that these three ligands mainly bound to subdomain IIA of HSA and were closer to tryptophan residues. In EGCG + DOX/EPI + HSA ternary system, the effect of one drug on the binding ability of another drug was discussed. The influences of the individual and combined binding of EGCG and DOX/EPI on the secondary structure and particle size of HSA were investigated by CD spectroscopy and DLS, respectively. Moreover, the synergistic cytotoxicity of EGCG and DOX/EPI as well as their complexes with HSA were discussed. Obtained results would provide beneficial information on the combination of EGCG and anthracyclines in clinic.

Development of R8 modified epirubicin-dihydroartemisinin liposomes for treatment of non-small-cell lung cancer.

Presently, there are no few anticancer drugs that have been used clinically due to their poor targeting ability, short half-life period, non-selective distributions, generation of vasculogenic mimicry (VM) channels, high metastasis, and high recurrence rate. This study aimed to explore the effects of R8 modified epirubicin-dihydroartemisinin liposomes that could target non-small-cell lung cancer (NSCLC) cells, destroy VM channels, inhibit tumor metastasis, and explain the possible underlying mechanism. In vitro assays indicated that R8 modified epirubicin-dihydroartemisinin liposomes with ideal physicochemical characteristics could exhibit not only powerful cytotoxicity on A549 cells, but also the effective suppression of VM channels and tumor metastasis. Mechanistic studies manifested that R8 modified epirubicin-dihydroartemisinin liposomes could down-regulate the levels of VE-Cad, TGF-ß1, MMP-2, and HIF-1α. In vivo assays indicated that R8 modified epirubicin-dihydroartemisinin liposomes could both increase the selective accumulation of chemotherapeutic drugs at tumor sites and show a targeting conspicuous of antitumor efficacy. In conclusion, the R8 modified epirubicin-dihydroartemisinin liposomes prepared in this study provide a treatment strategy with high efficiency for NSCLC.

Gradiently degraded electrospun polyester scaffolds with cytostatic for urothelial carcinoma therapy.

Kidney-sparing surgery is the preferred treatment strategy for low-risk upper tract urothelial carcinoma (UTUC). However, after this procedure, prevention of the carcinoma recurrence in the ureter and supporting the ureter with a ureteral stent are necessary. Biodegradable drug-loaded ureteral scaffolds are able to maintain their long-term effective drug concentrations in the lesion sites without the defects of traditional ureteral stents, which may address both issues simultaneously. The purpose of this study was to reveal the possibility of the controlled delivery of epirubicin (EPI) via gradiently degraded electrospun poly(ε-caprolactone) (PCL)/poly(lactide-co-glycolide) (PLGA) scaffolds to evaluate their antitumor activity against UTUC. The degradable PCL/PLGA scaffolds containing 15.0 and 25.0 wt% PCL and loading of 0, 5.0, and 10.0 wt% EPI were successfully fabricated via electrospinning. In addition, the PCL/PLGA scaffolds showed sustained and controlled degradation and drug release kinetics, that is, their degradation and drug release rates slowed with an increase in the ratio of PCL. The EPI-loaded PCL/PLGA scaffolds showed excellent antitumor activities both in vitro and in vivo without apparent systemic toxicity. Overall, the gradiently-degraded EPI-loaded electrospun polyester scaffolds are potential ureteral stent tubes for the local inhibition of the recurrence of UTUC, where the continued release of EPI can prevent the subsequent proliferation of residual tumor cells, and the gradient degradation is consistent with the repair of the ureter.

Technetium-99m radiolabeling and biological study of epirubicin for in vivo imaging of multi-drug-resistant Staphylococcus aureus infections via single photon emission computed tomography.

The development of functional imaging is a promising strategy for diagnosis and treatment of infectious and cancerous diseases. In this study, epirubicin was developed as a [99m Tc]-labeled radiopharmaceutical for the imaging of multi-drug-resistant Staphylococcus aureus infections. The labeling was carried out using sodium pertechnetate (Na99m TcO4 ; ~370 MBq). The other parameters such as amount of ligand, reducing agent (SnCl2 .2H2 O), and pH were optimized. The highest labeling yield ≥96.98% was achieved when 0.3 mg epirubicin, 13 µg SnCl2 .2H2 O, and ~370 MBq Na99m TcO4 were incubated at pH 7 for 15 min in the presence of ascorbic acid at room temperature. Radiochemical purity, stability, charge, and glomerular filtration rate were studied to evaluate the biological compatibility for in vivo administration. Biodistribution investigations showed radiotracer uptake (13.89 ± 1.56% ID/gm organ) by liver and 7.79 ± 0.38% ID/gm organ by kidneys at 30 min post-injection which promisingly wash out at 24 hr post-injection. Scintigraphy study showed selective uptake in S. aureus-infected tissues in contrast to turpentine oil-induced inflamed tissues. Target-to-non-target ratio (6.7 ± 0.05) was calculated at 1 hr post-injection using SPECT gamma camera. The results of this study reveal that the [99m Tc]-epirubicin can be a choice of imaging and monitoring the treatment process of multi-drug resistant S. aureus bacterial infections.

Preparation and evaluation of tumour microenvironment response multistage nanoparticles for epirubicin delivery and deep tumour penetration.

Poor tumour penetration became a major challenge for the use of nanoparticles in anticancer therapy. To further enhance the tumour penetration efficiency, we developed a tumour-microenvironment-responsive multistage drug delivery system which was formed layer by layer via electrostatic interaction with cationic drug-loaded nanoparticles, hyaluronidase (HAase) and iRGD-modified gelatin (G-iRGD). The drug-loaded nanoparticles were formed by self-assembling mPEG-PDPA-PG and encapsulation with epirubicin (EPI). Due to the protonation of tertiary amine groups of PDPA segment in acid environment, mPEG-PDPA-PG could enhance the lysosomal escape and the intracellular release of EPI. This NPs/HAase/G-iRGD delivery system showed great biocompatibility in vitro, confirmed by MTT method. In vitro spherical tumour model penetration and in vivo tumour permeability investigation showed HAase coated NPs-EPI (NPs-EPI/HAase) could significantly enhance its penetrating efficiency. The NPs-EPI/HAase could assist in breaking down the hyaluronic acid (HA), which was a key component of extracellular matrix and thereby improving mass transport within the solid tumours. The flow cytometry studies showed that G-iRGD coated NPs-EPI (NPs-EPI/G-iRGD) was more easily taken up by HepG2 cells than gelatin coated NPs-EPI (NPs-EPI/G), which revealed the active targeting ability of iRGD. The results proved that this NPs/HAase/G-iRGD delivery system showed promising potential in enhancing tumour penetration efficiency.

RP-HPLC-UV Method for Estimation of Fluorouracil-Epirubicin-Cyclophosphamide and Their Metabolite Mixtures in Human Plasma (Matrix).

A combination of 5-fluorouracil (FU), epirubicin (EP) and cyclophosphamide (CP) is routinely employed in the treatment of breast cancer. The objective of this study was to develop a reverse phase high-performance liquid chromatography (HPLC)-UV method for simultaneous quantitative analysis of the triple-drug and their metabolites in plasma. RP-HPLC system with a C18 column and a diode array detector was employed. The plasma samples were precipitated with acetonitrile and the supernatant was dried under a flow of nitrogen gas. The mobile phase comprised of two combinations, water (pH 4.0) and methanol (98:2 v/v), and water (pH 4.0):methanol:acetonitrile (70:13:17 v/v/v). The retention times for the compounds were determined and the parameters of validation established in plasma indicated the robustness and reliability. The corresponding HPLC peaks were confirmed using electron spray ionization mass spectrometry. FU and metabolites had a recovery of >93%; EP, epirubicinol and CP were >78% from plasma. Stability at 28-30°C in water (pH 4.0) of FU, 5,6-dihydro-5-fluorouracil and EP were higher followed by CP, EPol, fluorodeoxyuridine and fluorouridine (FUR). Storage of the drug-spiked plasma at -80°C assessed for 72 h showed a small but significant (P < 0.05) change in the recovery of FUR and EP. The method was validated in patient's plasma samples (n = 6).

Lipid nanoparticle-based co-delivery of epirubicin and BCL-2 siRNA for enhanced intracellular drug release and reversing multidrug resistance.

At present, combined therapy has become an effective strategy for the treatment of cancer. Co-delivery of the chemotherapeutic drugs and siRNA can more effectively inhibit tumor growth by nano drug delivery systems (NDDSs). Here, we prepared and evaluated a multifunctional envelope-type nano device (MEND). This MEND was a kind of composite lipid-nanoparticles possessing both the properties of liposomes and nanoparticles. In this study, an acid-cleavable ketal containing poly (ß-amino ester) (KPAE) was used to bind siBCL-2 and the KPAE/siBCL-2 complexes were further coated by epirubicin (EPI) containing lipid to form EPI/siBCL-2 dual loaded lipid-nanoparticles. The results showed that the average size of EPI/siBCL-2-MEND was about 120 nm, and the average zeta potential was about 41 mV. The encapsulation efficiency (EE) of EPI and siBCL-2 was 86.13% and 97.07%, respectively. EPI/siBCL-2 dual loaded lipid-nanoparticles showed enhanced inhibition efficiency than individual EPI-loaded liposomes on HepG2 cells by MTT assay. Moreover, western blot experiment indicated co-delivery of EPI/siBCL-2 can significantly down-regulate the expression of P-glycoprotein (P-gp), while free EPI and EPI-loaded liposomes up-regulated it. Therefore, the strategy of co-delivering EPI and siBCL-2 simultaneously by lipid-nanoparticles showed promising potential in reversing multidrug resistance of tumor cells.

A novel FAPα-based Z-Gly-Pro epirubicin prodrug for improving tumor-targeting chemotherapy.

Fibroblast activation protein-α (FAPα) is a serine protease of the post-prolyl peptidase family that is specifically expressed in the majority of human epithelial tumors, but not in normal tissues. In this study, we demonstrated the anti-tumor activity of a novel targeting drug formed by conjugating epirubicin (EPI) with an FAPα-specific dipeptide (Z-Gly-Pro) and named it Z-GP-EPI. Consistent with this tumor-targeting delivery strategy, the results illustrated that Z-GP-EPI could release EPI efficiently after incubating with FAPα and could exhibit similar antitumor effects as EPI in vitro in FAPα over-expressed tumor cells (4T1/FAPα+). Furthermore, the evaluation of antitumor activity of Z-GP-EPI in vivo was implemented in a 4T1/FAPα+ tumor-bearing mice xenograft model. Our results illustrated that Z-GP-EPI had similar antitumor effects in 4T1/FAPα+ tumor-bearing mice and showed no visible cardiotoxicity side effects compared with free EPI. Thus, our study indicated that this FAPα-activated prodrug targeting strategy may provide a new mechanism for the targeted delivery of antitumor agents and improve their safety levels.

Screening in larval zebrafish reveals tissue-specific distribution of fifteen fluorescent compounds.

The zebrafish is a prominent vertebrate model for low-cost in vivo whole organism screening. In our recent screening of the distribution patterns of fluorescent compounds in live zebrafish larvae, fifteen compounds with tissue-specific distributions were identified. Several compounds were observed to accumulate in tissues where they were reported to induce side-effects, and compounds with similar structures tended to be enriched in the same tissues, with minor differences. In particular, we found three novel red fluorescent bone-staining dyes: purpurin, lucidin and 3-hydroxy-morindone; purpurin can effectively label bones in both larval and adult zebrafish, as well as in postnatal mice, without significantly affecting bone mass and density. Moreover, two structurally similar chemotherapeutic compounds, doxorubicin and epirubicin, were observed to have distinct distribution preferences in zebrafish. Epirubicin maintained a relatively higher concentration in the liver, and performed better in inhibiting hepatic hyperplasia caused by the over-expression of krasG12V In total, our study suggests that the transparent zebrafish larvae serve as valuable tools for identifying tissue-specific distributions of fluorescent compounds.

Polysialic acid-modifying liposomes for efficient delivery of epirubicin, in-vitro characterization and in-vivo evaluation.

Polysialic acid (PSA) serves as a hydrophilic polymer and affords conjugated biologically active molecules a longer circulation time in vivo. Furthermore, PSA could potentially target tumor tissues and help achieve better curative effects. In this study, PSA was conjugated with octadecyl dimethyl betaine (BS18) to yield a PSA-BS18 conjugate. The PSA-BS18 modified liposomal epirubicin (EPI-SL), had a particle size of 133.63±0.92nm, a zeta potential of -26.23±1.50mV and an encapsulation efficiency (%EE) of 96.23±1.16%. In vitro release studies showed that PSA-BS18 could delay EPI release from the modified liposomes. The MTT assay suggested that EPI-SL led to stronger cytotoxic activity than that exhibited by common and PEGylated liposomes. The pharmacokinetic study showed that EPI-SL prolonged the residence time of the EPI in the blood compared with that observed from common liposomes. Bio-distribution results obtained from tumor-bearing mice clearly demonstrated that PSA-BS18 increased the accumulation of modified liposomes in tumors compared with that of common liposomes. In the antitumor efficacy study, EPI-SL showed the best antitumor and life-prolonging effects among all of the tested formulations. These findings strongly indicate EPI-SL might have great potential as an effective approach for anticancer therapy.

Human cytosolic sulfotransferase SULT1C4 mediates the sulfation of doxorubicin and epirubicin.

Doxorubicin, an anthracycline, has been reported to be excreted in sulfate conjugated form. The current study aimed to identify the human cytosolic sulfotransferase(s) (SULT(s)) that is(are) capable of sulfating doxorubicin and its analog epirubicin, and to verify whether sulfation of doxorubicin and epirubicin may occur under metabolic conditions. A systematic analysis of thirteen known human SULTs, previously cloned, expressed, and purified, revealed SULT1C4 as the only human SULT capable of sulfating doxorubicin and epirubicin. Cultured HepG2 human hepatoma cells and Caco-2 human colon carcinoma cells were labeled with [(35)S]sulfate in the presence of different concentrations of doxorubicin or epirubicin. Analysis of spent labeling media showed the generation and release of [(35)S]sulfated doxorubicin and epirubicin by HepG2 cells and Caco-2 cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed the expression of SULT1C4 in both HepG2 cells and Caco-2 cells. These results provided a molecular basis underlying the previous finding that sulfate-conjugated doxorubicin was excreted in the urine of patients treated with doxorubicin.