Protective effects of esculetin against doxorubicin-induced toxicity correlated with oxidative stress in rat liver: In vivo and in silico studies.

Doxorubicin (DOX) is widely used in cancer treatment but the dose-related toxicity of DOX on organs including the liver limit its use. Therefore, there is great interest in combining DOX with natural compounds with antioxidant properties to reduce toxicity and increase drug efficacy. Esculetin is a natural coumarin derivative with biological properties encompassing anti-inflammatory and antioxidant activities. In light of these properties, this study was meticulously crafted to investigate the potential of esculetin in preventing doxorubicin (DOX)-induced hepatotoxicity in Sprague-Dawley rats. The rats were divided into a total of six groups: control group, DOX group (administered DOX at a cumulative dose of 5 mg/kg intraperitoneally every other day for 2 weeks), E50 group (administered 50 mg/kg of esculetin intraperitoneally every day), E100 group (administered 100 mg/kg of esculetin intraperitoneally every day) and combined groups (DOX + E50 and DOX + E100) in which esculetin was administered together with DOX. The treatments, both with DOX alone and in combination with E50, manifested a reduction in catalase (CAT mRNA) levels in comparison to the control group. Notably, the enzymatic activities of superoxide dismutase (SOD), CAT, and glutathione peroxidase (GPx) witnessed significant decreases in the liver of rats treated with DOX. Moreover, DOX treatment induced a statistically significant elevation in malondialdehyde (MDA) levels, coupled with a concurrent decrease in glutathione (GSH) levels. Additionally, molecular docking studies were conducted. However, further studies are needed to confirm the hepatoprotective properties of esculetin and to precisely elucidate its mechanisms of action.

Artificial intelligence-enabled prediction of chemotherapy-induced cardiotoxicity from baseline electrocardiograms.

Anthracyclines can cause cancer therapy-related cardiac dysfunction (CTRCD) that adversely affects prognosis. Despite guideline recommendations, only half of the patients undergo surveillance echocardiograms. An AI model detecting reduced left ventricular ejection fraction from 12-lead electrocardiograms (ECG) (AI-EF model) suggests ECG features reflect left ventricular pathophysiology. We hypothesized that AI could predict CTRCD from baseline ECG, leveraging the AI-EF model's insights, and developed the AI-CTRCD model using transfer learning on the AI-EF model. In 1011 anthracycline-treated patients, 8.7% experienced CTRCD. High AI-CTRCD scores indicated elevated CTRCD risk (hazard ratio (HR), 2.66; 95% CI 1.73-4.10; log-rank p < 0.001). This remained consistent after adjusting for risk factors (adjusted HR, 2.57; 95% CI 1.62-4.10; p < 0.001). AI-CTRCD score enhanced prediction beyond known factors (time-dependent AUC for 2 years: 0.78 with AI-CTRCD score vs. 0.74 without; p = 0.005). In conclusion, the AI model robustly stratified CTRCD risk from baseline ECG.

5-Hydroxytryptophan acts as a gap junction inhibitor to limit the spread of chemotherapy-induced cardiomyocyte injury and mitochondrial dysfunction.

Anthracycline chemotherapeutics like doxorubicin (DOX) are widely used against various cancers but are accompanied by severe cardiotoxic effects that can lead to heart failure. Through whole transcriptome sequencing and pathological tissue analysis in a murine model, our study has revealed that DOX impairs collagen expression in the early phase, causing extracellular matrix anomalies that weaken the mechanical integrity of the heart. This results in ventricular wall thinning and dilation, exacerbating cardiac dysfunction. In this work, we have identified 5-hydroxytryptophan (5-HTP) as a potent inhibitor of gap junction communication. This inhibition is key to limiting the spread of DOX-induced cardiotoxicity. Treatment with 5-HTP effectively countered the adverse effects of DOX on the heart, preserving ventricular structure and ejection fraction. Moreover, 5-HTP enhanced mitochondrial respiratory function, as shown by the O2k mitochondrial function assay, by improving mitochondrial complex activity and ATP production. Importantly, the cardioprotective benefits of 5-HTP did not interfere with DOX's ability to combat cancer. These findings shed light on the cardiotoxic mechanisms of DOX and suggest that 5-HTP could be a viable strategy to prevent heart damage during chemotherapy, offering a foundation for future clinical development. This research opens the door for 5-HTP to be considered a dual-purpose agent that can protect the heart without compromising the oncological efficacy of anthracycline chemotherapy.

Controlled Dissociation of Polymeric Micelles in Response to Oxidative Stress.

Nanoparticle-based drug carriers that can respond to oxidative stress in tumor tissue have attracted attention for site-specific drug release. Taking advantage of the characteristic microenvironment in tumors, one of the attractive directions in drug delivery research is to design drug carriers that release drugs upon oxidation. A strategy to incorporate oxidation-sensitive thioether motifs such as thiomorpholine acrylamide (TMAM) to drug carriers has been often used to achieve oxidation-induced dissociation, thereby targeted drug release. However, those delivery systems often suffer from a slow dissociation rate due to the intrinsic hydrophobicity of the thioether structures. In this study, we aimed to enhance the dissociation rate of TMAM-based micelles upon oxidation. The random copolymers of N-isopropylacrylamide and TMAM (P(NIPAM/TMAM)) were designed as an oxidation-sensitive segment that showed a fast response to oxidative stress. We first synthesized P(NIPAM/TMAM) copolymers with different NIPAM:TMAM molar ratios. Those copolymers exhibited low critical solution temperatures (LCSTs) below 32 °C, which shifted to higher temperatures after oxidation. The changes in LCSTs depend on the NIPAM:TMAM molar ratios. At the NIPAM:TMAM molar ratio of 82:18, the LCSTs before and after oxidation were 17 and 54 °C, respectively. We then prepared micelles from the diblock copolymers of poly(N-acryloyl morpholine) (PAM) and P(NIPAM/TMAM). The micelles showed an accelerated dissociation rate upon oxidation compared to the micelles without NIPAM units. Furthermore, the doxorubicin (Dox)-loaded micelles showed enhanced relative toxicity in human colorectal cancer (HT29) cells over human umbilical vein endothelial cells (HUVECs). Our novel strategy to design an oxidation-sensitive micellar core comprising a P(NIPAM/TMAM) segment can be used as a chemotherapeutic delivery system that responds to an oxidative tumor microenvironment in an appropriate time scale.

A new peucemycin derivative and impacts of peuR and bldA on peucemycin biosynthesis in Streptomyces peucetius.

Streptomyces peucetius ATCC 27952 is known to produce a variety of secondary metabolites, including two important antitumor anthracyclines: daunorubicin and doxorubicin. Identification of peucemycin and 25-hydroxy peucemycin (peucemycin A), as well as their biosynthetic pathway, has expanded its biosynthetic potential. In this study, we isolated a new peucemycin derivative and identified it as 19-hydroxy peucemycin (peucemycin B). Its antibacterial activity was lower than those of peucemycin and peucemycin A. On the other hand, this newly identified peucemycin derivative had higher anticancer activity than the other two compounds for MKN45, NCI-H1650, and MDA-MB-231 cancer cell lines with IC50 values of 76.97 µM, 99.68 µM, and 135.2 µM, respectively. Peucemycin biosynthetic gene cluster revealed the presence of a SARP regulator named PeuR whose role was unknown. The presence of the TTA codon in the peuR and the absence of global regulator BldA in S. peucetius reduced its ability to regulate the peucemycin biosynthetic gene cluster. Hence, different mutants harboring these genes were prepared. S. peucetius bldA25 harboring bldA produced 1.75 times and 1.77 times more peucemycin A (11.8 mg/L) and peucemycin B (21.2 mg/L), respectively, than the wild type. On the other hand, S. peucetius R25 harboring peuR produced 1.86 and 1.79 times more peucemycin A (12.5 mg/L) and peucemycin B (21.5 mg/L), respectively, than the wild type. Finally, strain S. peucetius bldAR25 carrying bldA and peuR produced roughly 3.52 and 2.63 times more peucemycin A (23.8 mg/L) and peucemycin B (31.5 mg/L), respectively, than the wild type. KEY POINTS: • This study identifies a new peucemycin derivative, 19-hydroxy peucemycin (peucemycin B). • The SARP regulator (PeuR) acts as a positive regulator of the peucemycin biosynthetic gene cluster. • The overexpression of peuR and heterologous expression of bldA increase the production of peucemycin derivatives.

Synthesis and antitumor activity of cyclopentane-fused anthraquinone derivatives.

In our pursuit of developing novel analogs of anthracyclines with enhanced antitumor efficacy and safety, we have designed a synthesis scheme for 4,11-dihydroxy-5,10-dioxocyclopenta[b]anthracene-2-carboxamides. These newly synthesized compounds exhibit remarkable antiproliferative potency against various mammalian tumor cell lines, including those expressing activated mechanisms of multidrug resistance. The structure of the diamine moiety in the carboxamide side chain emerges as a critical determinant for anticancer activity and interaction with key targets such as DNA, topoisomerase 1, and ROS induction. Notably, the introduced modification to the doxorubicin structure results in significantly increased lipophilicity, cellular uptake, and preferential distribution in lysosomes. Consequently, while maintaining an impact on anthracyclines targets, these novel derivatives also demonstrate the potential to induce cytotoxicity through pathways associated with lysosomes. In summary, derivatives of cyclic diamines, particularly 3-aminopyrrolidine, can be considered a superior choice compared to aminosugars for incorporation into natural and semi-synthetic anthracyclines or new anthraquinone derivatives, aiming to circumvent efflux-mediated drug resistance.

Hypoxia-Responsive Golgi-Targeted Prodrug Assembled with Anthracycline for Improved Antitumor and Antimetastasis Efficacy.

Tumor metastasis is an intricate multistep process regulated via various proteins and enzymes modified and secreted by swollen Golgi apparatus in tumor cells. Thus, Golgi complex is considered as an important target for the remedy of metastasis. Currently, Golgi targeting technologies are mostly employed in Golgi-specific fluorescent probes for diagnosis, but their applications in therapy are rarely reported. Herein, we proposed a prodrug (INR) that can target and destroy the Golgi apparatus, which consisted of indomethacin (IMC) as the Golgi targeting moiety and retinoic acid (RA), a Golgi disrupting agent. The linker between IMC and RA was designed as a hypoxia-responsive nitroaromatic structure, which ensured the release of the prototype drugs in the hypoxic tumor microenvironment. Furthermore, INR could be assembled with pirarubicin (THP), an anthracycline, to form a carrier-free nanoparticle (NP) by emulsion-solvent evaporation method. A small amount of mPEG2000-DSPE was added to shield the positive charges and improve the stability of the nanoparticle to obtain PEG-modified nanoparticle (PNP). It was proved that INR released the prototype drugs in tumor cells and hypoxia promoted the release. The Golgi destructive effect of RA in INR was amplified owing to the Golgi targeting ability of IMC, and IMC also inhibited the protumor COX-2/PGE2 signaling. Finally, PNP exhibited excellent curative efficacy on 4T1 primary tumor and its pulmonary and hepatic metastasis. The small molecular therapeutic prodrug targeting Golgi apparatus could be adapted to multifarious drug delivery systems and disease models, which expanded the application of Golgi targeting tactics in disease treatment.

Dexrazoxane does not mitigate early vascular toxicity induced by doxorubicin in mice.

Apart from cardiotoxicity, the chemotherapeutic agent doxorubicin (DOX) provokes acute and long-term vascular toxicity. Dexrazoxane (DEXRA) is an effective drug for treatment of DOX-induced cardiotoxicity, yet it remains currently unknown whether DEXRA prevents vascular toxicity associated with DOX. Accordingly, the present study aimed to evaluate the protective potential of DEXRA against DOX-related vascular toxicity in a previously-established in vivo and ex vivo model of vascular dysfunction induced by 16 hour (h) DOX exposure. Vascular function was evaluated in the thoracic aorta in organ baths, 16h after administration of DOX (4 mg/kg) or DOX with DEXRA (40 mg/kg) to male C57BL6/J mice. In parallel, vascular reactivity was evaluated after ex vivo incubation (16h) of murine aortic segments with DOX (1 µM) or DOX with DEXRA (10 µM). In both in vivo and ex vivo experiments, DOX impaired acetylcholine-stimulated endothelium-dependent vasodilation. In the ex vivo setting, DOX additionally attenuated phenylephrine-elicited vascular smooth muscle cell (VSMC) contraction. Importantly, DEXRA failed to prevent DOX-induced endothelial dysfunction and hypocontraction. Furthermore, RT-qPCR and Western blotting showed that DOX decreased the protein levels of topoisomerase-IIß (TOP-IIß), a key target of DEXRA, in the heart, but not in the aorta. Additionally, the effect of N-acetylcysteine (NAC, 10 µM), a reactive oxygen species (ROS) scavenger, was evaluated ex vivo. NAC did not prevent DOX-induced impairment of acetylcholine-stimulated vasodilation. In conclusion, our results show that DEXRA fails to prevent vascular toxicity resulting from 16h DOX treatment. This may relate to DOX provoking vascular toxicity in a ROS- and TOP-IIß-independent way, at least in the evaluated acute setting. However, it is important to mention that these findings only apply to the acute (16h) treatment period, and further research is warranted to delineate the therapeutic potential of DEXRA against vascular toxicity associated with longer-term repetitive DOX dosing.

Multicenter, Prospective, Randomized Controlled Trial of High-Sensitivity Cardiac Troponin I-Guided Combination Angiotensin Receptor Blockade and Beta-Blocker Therapy to Prevent Anthracycline Cardiotoxicity: The Cardiac CARE Trial.

BACKGROUND: Anthracycline-induced cardiotoxicity has a variable incidence, and the development of left ventricular dysfunction is preceded by elevations in cardiac troponin concentrations. Beta-adrenergic receptor blocker and renin-angiotensin system inhibitor therapies have been associated with modest cardioprotective effects in unselected patients receiving anthracycline chemotherapy. METHODS: In a multicenter, prospective, randomized, open-label, blinded end-point trial, patients with breast cancer and non-Hodgkin lymphoma receiving anthracycline chemotherapy underwent serial high-sensitivity cardiac troponin testing and cardiac magnetic resonance imaging before and 6 months after anthracycline treatment. Patients at high risk of cardiotoxicity (cardiac troponin I concentrations in the upper tertile during chemotherapy) were randomized to standard care plus cardioprotection (combination carvedilol and candesartan therapy) or standard care alone. The primary outcome was adjusted change in left ventricular ejection fraction at 6 months. In low-risk nonrandomized patients with cardiac troponin I concentrations in the lower 2 tertiles, we hypothesized the absence of a 6-month change in left ventricular ejection fraction and tested for equivalence of ±2%. RESULTS: Between October 2017 and June 2021, 175 patients (mean age, 53 years; 87% female; 71% with breast cancer) were recruited. Patients randomized to cardioprotection (n=29) or standard care (n=28) had left ventricular ejection fractions of 69.4±7.4% and 69.1±6.1% at baseline and 65.7±6.6% and 64.9±5.9% 6 months after completion of chemotherapy, respectively. After adjustment for age, pretreatment left ventricular ejection fraction, and planned anthracycline dose, the estimated mean difference in 6-month left ventricular ejection fraction between the cardioprotection and standard care groups was -0.37% (95% CI, -3.59% to 2.85%; P=0.82). In low-risk nonrandomized patients, baseline and 6-month left ventricular ejection fractions were 69.3±5.7% and 66.4±6.3%, respectively: estimated mean difference, 2.87% (95% CI, 1.63%-4.10%; P=0.92, not equivalent). CONCLUSIONS: Combination candesartan and carvedilol therapy had no demonstrable cardioprotective effect in patients receiving anthracycline-based chemotherapy with high-risk on-treatment cardiac troponin I concentrations. Low-risk nonrandomized patients had similar declines in left ventricular ejection fraction, bringing into question the utility of routine cardiac troponin monitoring. Furthermore, the modest declines in left ventricular ejection fraction suggest that the value and clinical impact of early cardioprotection therapy need to be better defined in patients receiving high-dose anthracycline. REGISTRATION: URL: https://doi.org; Unique identifier: 10.1186/ISRCTN24439460. URL: https://www.clinicaltrialsregister.eu/ctr-search/search; Unique identifier: 2017-000896-99.

Breviscapine reverses doxorubicin resistance in breast cancer and its related mechanisms.

BACKGROUND: Based on the effect of breviscapine (BRE) on reversing drug resistance of human breast cancer cell line MCF-7/doxorubicin (Dox), the mechanism was preliminarily explored. METHODS: The methyl thiazolyl tetrazolium (MTT) method was introduced to detect inhibitory effect of Dox alone or in combination with BRE on MCF-7 (M) and MCF-7/Dox (MD) cells, and the inhibitory concentration (IC50 ) was obtained. Cell apoptosis and Dox concentration was assessed by flow cytometry. The drug resistance multiple and reversal fold were calculated. Western blot was performed to evaluate the expression of Bcl-2, Bax, EGFR, p-EGFR, P-gp, caspase-3, and cleaved-caspase-3 protein in cells. The efflux of Rho-123 was measured by flow cytometry and fluorescence microscopy. RESULTS: The IC50 of Dox on MD and M cells was 16.67 and 0.71 µg/mL, respectively, with a drug resistance ratio of 23.48 times. The IC50 of Dox combined with BRE on MD cells was 5.62 µg/mL, with a reversal ratio of 2.97 times. BRE greatly enhanced Dox-induced apoptosis of MD cells. Bax and cleaved-caspase-3 (proapoptotic protein) expression were obviously increased, while Bcl-2 (antiapoptotic protein) expression was significantly decreased after BRE treatment. BRE inhibited EGFR activation and P-gp expression. BRE increased the intracellular accumulation of Dox in MD cells by P-gp. CONCLUSION: BRE could increase the MD sensitivity to Dox via increasing Bax and cleaved-caspase-3 expression and inhibiting Bcl-2 expression, thereby promoting cell apoptosis. BRE reversed Dox resistance of MD cells by increasing Dox intracellular accumulation through inhibiting P-gp expression via EGFR.

Development of Biaryl-Containing Aldo-Keto Reductase 1C3 (AKR1C3) Inhibitors for Reversing AKR1C3-Mediated Drug Resistance in Cancer Treatment.

Aldo-keto reductase 1C3 (AKR1C3) is correlated with tumor development and chemotherapy resistance. The catalytic activity of the enzyme has been recognized as one of the important factors in inducing anthracycline (ANT) resistance in cancer cells. Inhibition of AKR1C3 activity may provide a promising approach to restore the chemosensitivity of ANT-resistant cancers. Herein, a series of biaryl-containing AKR1C3 inhibitors has been developed. The best analogue S07-1066 selectively blocked AKR1C3-mediated reduction of doxorubicin (DOX) in MCF-7 transfected cell models. Furthermore, co-treatment of S07-1066 significantly synergized DOX cytotoxicity and reversed the DOX resistance in MCF-7 cells overexpressing AKR1C3. The potential synergism of S07-1066 over DOX cytotoxicity was demonstrated in vitro and in vivo. Our findings indicate that inhibition of AKR1C3 potentially enhances the therapeutic efficacy of ANTs and even suggests that AKR1C3 inhibitors may serve as effective adjuvants to overcome AKR1C3-mediated chemotherapy resistance in cancer treatment.

Nuclear translocation of mitochondrial dehydrogenases as an adaptive cardioprotective mechanism.

Chemotherapy-induced cardiac damage remains a leading cause of death amongst cancer survivors. Anthracycline-induced cardiotoxicity is mediated by severe mitochondrial injury, but little is known about the mechanisms by which cardiomyocytes adaptively respond to the injury. We observed the translocation of selected mitochondrial tricarboxylic acid (TCA) cycle dehydrogenases to the nucleus as an adaptive stress response to anthracycline-cardiotoxicity in human induced pluripotent stem cell-derived cardiomyocytes and in vivo. The expression of nuclear-targeted mitochondrial dehydrogenases shifts the nuclear metabolic milieu to maintain their function both in vitro and in vivo. This protective effect is mediated by two parallel pathways: metabolite-induced chromatin accessibility and AMP-kinase (AMPK) signaling. The extent of chemotherapy-induced cardiac damage thus reflects a balance between mitochondrial injury and the protective response initiated by the nuclear pool of mitochondrial dehydrogenases. Our study identifies nuclear translocation of mitochondrial dehydrogenases as an endogenous adaptive mechanism that can be leveraged to attenuate cardiomyocyte injury.

Investigation of cardioprotective effect of lercanidipine on doxorubicin-induced cardiotoxicity.

Although doxorubicin (DOX) is an effective anti-neoplastic drug for many types of cancer, particularly dose-related cardiotoxicity limits the use of the drug. In this study, it was aimed to investigate the protective effect of lercanidipine (LRD) against DOX-induced cardiotoxicity. In our study, 40 Wistar albino female rats were randomly divided into 5 groups as control, DOX, LRD 0.5 (DOX + 0.5 mg/kg LRD), LRD 1 (DOX + 1 mg/kg LRD), and LRD 2 (DOX + 2 mg/kg LRD). At the end of the experiment, the rats were sacrificed, and their blood, heart, and endothelial tissues were examined biochemically, histopathologically, immunohistochemically, and genetically. According to our findings, necrosis, tumor necrosis factor alpha activity, vascular endothelial growth factor activity, and oxidative stress were increased in the heart tissues of the DOX group. In addition, DOX treatment caused the deteriorations in biochemical parameters, and levels of autophagy-related proteins, Atg5, Beclin1, and LC3-I/II were detected. Significant dose-related improvements in these findings were observed with LRD treatment. Besides, Atg5, LC3-I/II, and Beclin1 levels evaluated by western blot revealed that LRD exerts a tissue protective effect by regulating autophagy in endothelial tissue. LRD treatment, which is a new-generation calcium channel blocker, showed antioxidant, anti-inflammatory, and anti-apoptotic properties in heart and endothelial tissue in a dose-dependent manner and also showed protective activity by regulating autophagy in endothelial tissue. With studies evaluating these mechanisms in more detail, the protective effects of LRD will be revealed more clearly.

Effects of Exercise Preconditioning on Doxorubicin-Induced Liver and Kidney Toxicity in Male and Female Rats.

Doxorubicin (DOX) is a highly effective chemotherapy agent prescribed for cancer treatment. However, the clinical use of DOX is limited due to off-target toxicity in healthy tissues. In this regard, hepatic and renal metabolic clearance results in DOX accumulation within these organ systems. Within the liver and kidneys, DOX causes inflammation and oxidative stress, which promotes cytotoxic cellular signaling. While there is currently no standard of care to treat DOX hepatic- and nephrotoxicity, endurance exercise preconditioning may be an effective intervention to prevent elevations in liver alanine transaminase (ALT) and aspartate aminotransferase (AST) and to improve kidney creatinine clearance. To determine whether exercise preconditioning is sufficient to reduce liver and kidney toxicity resulting from acute exposure to DOX chemotherapy treatment, male and female Sprague-Dawley rats remained sedentary or were exercise trained prior to saline or DOX exposure. Our findings demonstrate that DOX treatment elevated AST and AST/ALT in male rats, with no effects of exercise preconditioning to prevent these increases. We also showed increased plasma markers of renin-angiotensin-aldosterone system (RAAS) activation and urine markers of proteinuria and proximal tubule damage, with male rats revealing greater differences compared to females. Exercise preconditioning showed improved urine creatinine clearance and reduced cystatin c in males, while females had reduced plasma angiotensin II (AngII) levels. Our results demonstrate both tissue- and sex-specific responses related to the effects of exercise preconditioning and DOX treatment on markers of liver and kidney toxicity.

In Silico and In Vitro Assessment of Carbonyl Reductase 1 Inhibition Using ASP9521-A Potent Aldo-Keto Reductase 1C3 Inhibitor with the Potential to Support Anticancer Therapy Using Anthracycline Antibiotics.

Anthracycline antibiotics (ANT) are among the most widely used anticancer drugs. Unfortunately, their use is limited due to the development of drug resistance and cardiotoxicity. ANT metabolism, performed mainly by two enzymes-aldo-keto reductase 1C3 (AKR1C3) and carbonyl reductase 1 (CBR1)-is one of the proposed mechanisms generated by the described effects. In this study, we evaluated the CBR1 inhibitory properties of ASP9521, a compound already known as potent AKR1C3 inhibitor. First, we assessed the possibility of ASP9521 binding to the CBR1 catalytic site using molecular docking and molecular dynamics. The research revealed a potential binding mode of ASP9521. Moderate inhibitory activity against CBR1 was observed in studies with recombinant enzymes. Finally, we examined whether ASP9521 can improve the cytotoxic activity of daunorubicin against human lung carcinoma cell line A549 and assessed the cardioprotective properties of ASP9521 in a rat cardiomyocytes model (H9c2) against doxorubicin- and daunorubicin-induced toxicity. The addition of ASP9521 ameliorated the cytotoxic activity of daunorubicin and protected rat cardiomyocytes from the cytotoxic effect of both applied drugs. Considering the favorable bioavailability and safety profile of ASP9521, the obtained results encourage further research. Inhibition of both AKR1C3 and CBR1 may be a promising method of overcoming ANT resistance and cardiotoxicity.

Topoisomerase II inhibitors design: Early studies and new perspectives.

The DNA topoisomerase enzymes are widely distributed throughout all spheres of life and are necessary for cell function. Numerous antibacterial and cancer chemotherapeutic drugs target the various topoisomerase enzymes because of their roles in maintaining DNA topology during DNA replication and transcription. Agents derived from natural products, like anthracyclines, epipodophyllotoxins and quinolones, have been widely used to treat a variety of cancers. A very active field of fundamental and clinical research is the selective targeting of topoisomerase II enzymes for cancer treatment. This thematic review summarizes the recent advances in the anticancer activity of the most potent topoisomerase II inhibitors (anthracyclines, epipodophyllotoxins and fluoroquinolones) their modes of action, and structure-activity relationships (SARs) organized chronologically in the last ten years from 2013 to 2023. The review also highlights the mechanism of action and SARs of promising new topoisomerase II inhibitors.

SNRPD1 conveys prognostic value on breast cancer survival and is required for anthracycline sensitivity.

BACKGROUND: Cancers harboring spliceosome mutations are highly sensitive to additional perturbations on the spliceosome that leads to the development of onco-therapeutics targeting the spliceosome and opens novel opportunities for managing aggressive tumors lacking effective treatment options such as triple negative breast cancers. Being the core spliceosome associated proteins, SNRPD1 and SNRPE have been both proposed as therapeutic targets for breast cancer management. Yet, their differences regarding their prognostic and therapeutic use as well as roles during carcinogenesis are largely unreported. METHODS: We conducted in silico analysis at gene expression and genetic levels to differentiate the clinical relevance of SNRPD1 and SNRPE, and explored their differential functionalities and molecular mechanistic associations with cancer in vitro. RESULTS: We showed that high SNRPD1 gene expression was prognostic of poor breast cancer survival whereas SNRPE was not. The SNRPD1 expression quantitative trait loci, rs6733100, was found independently prognostic of breast cancer survival using TCGA data. Silencing either SNRPD1 or SNRPE independently suppressed the growth of breast cancer cells, but decreased migration was only observed in SNRPD1-silenced cells. Knocking down SNRPD1 but not SNRPE triggers doxorubicin resistance in triple negative breast cancer cells. Gene enrichment and network analyses revealed the dynamic regulatory role of SNRPD1 on cell cycle and genome stability, and the preventive role of SNRPE against cancer stemness that may neutralize its promotive role on cancer cell proliferation. CONCLUSION: Our results differentiated the functionalities of SNRPD1 and SNRPE at both prognostic and therapeutic levels, and preliminarily explained the driving mechanism that requires additional explorations and validations.

Targeted delivery of epirubicin to breast cancer cells using poly-aptamer DNA nanocarriers prepared by the RCA method with multiple repeats of aptamers of FOXM1 and AS1411.

OBJECTIVE: We evaluated the DNA nanocarriers synthesized by rolling circle amplification (RCA), composed of multiple repeats of AS1411 and FOXM1 aptamers for targeted epirubicin delivery to breast cancer cells. METHODS: Agarose gel electrophoresis and scanning electron microscopy were used to nanostructure characterizing. Drug loading and drug release were determined by fluorometry. Cytotoxicity comparison by MTT assay was applied among epirubicin, nanoparticle, and complex (nanoparticle carrying epirubicin) in L929 (normal murine fibroblast) and 4T1 (murine mammary carcinoma) cells. Cellular epirubicin internalization was assessed by flow cytometry and fluorescence imaging. In vivo studies in 4T1 tumor-bearing BALB/c mice were conducted by monitoring tumor volume, mouse weight, and mortality rate and measuring the accumulated epirubicin in organs. RESULTS: The negatively charged nanoparticles were under 200 nm and stable. Fifty microliters of 6 µM epirubicin was loaded in 50 µL nanoparticle. Epirubicin release at acidic pH was more. Complex compared with epirubicin, had more entry and cytotoxicity in target cells (p value ≤.01), higher therapeutic effect (p value ≤.001), and tumor drug accumulation. CONCLUSION: The poly-aptamer nanocarriers have the characteristics of being safe, stable, efficient epirubicin loading, pH-dependent drug release, and tumor-targeting ability in vitro and in vivo.

The Anticancer Drug Daunomycin Directly Affects Gene Expression and DNA Structure.

Daunomycin (DM), an anthracycline antibiotic, is frequently used to treat various cancers, but the direct effects of DM on gene expression and DNA structure are unclear. We used an in vitro cell-free system, optimized with spermine (SP), to study the effect of DM on gene expression. A bimodal effect of DM on gene expression, weak promotion followed by inhibition, was observed with increasing concentration of DM. We also performed atomic force microscopy observation to measure how DM affects the higher-order structure of DNA induced with SP. DM destroyed SP-induced flower-like conformations of DNA by generating double-strand breaks, and this destructive conformational change of DNA corresponded to the inhibitory effect on gene expression. Interestingly, the weakly enhanced cell-free gene expression occurred as DNA conformations were elongated or relaxed at lower DM concentrations. We expect these newly unveiled DM effects on gene expression and the higher-order structure of DNA will contribute further to the development and refinement of useful anticancer therapy chemicals.