Different cytotoxicity and metabolism of doxorubicin, daunorubicin, epirubicin, esorubicin and idarubicin in cultured human and rat hepatocytes

Both cytotoxicity and metabolism of five anthracyclines, namely doxorubicin, daunorubicin, epirubicin, esorubicin and idarubicin, were investigated in primary cultures of both rat and human adult hepatocytes and, for comparison, in a rat liver epithelial cell line. Toxicity was assessed by morphological examination and measurement of lactate dehydrogenase leakage after 24 hr of treatment. The rank order of toxicity for both rat and human hepatocytes was esorubicin greater than doxorubicin = epirubicin greater than or equal to idarubicin greater than daunorubicin, and for rat epithelial cells: esorubicin greater than or equal to epirubicin greater than idarubicin = daunorubicin = doxorubicin. Human cells were around 2-fold less sensitive than rat hepatocytes to all anthracyclines. Anthracyclines and their metabolites were analyzed by HPLC. Differences in both the percentages and routes of metabolism were demonstrated between rat and human hepatocytes. The main metabolite was the 13-dihydro-derivative (-ol derivative) in both species from daunorubicin, idarubicin and esorubicin. Glucuronides of epirubicin and epirubicinol were found only in human hepatocytes. In addition, several unidentified metabolites were detected of esorubicin, idarubicin and daunorubicin in rat hepatocytes. In human hepatocytes, only one unknown metabolite from daunorubicin and doxorubicin was found to be formed by cells from a different donor. In spite of variations between individuals, human hepatocytes generally metabolized anthracyclines more actively than did rat hepatocytes. Rat liver epithelial cells were only able to convert daunorubicin and idarubicin, the two molecules which have the best affinity for the non-specific NADPH-dependent aldoketoreductase system. Three compounds (doxorubicin, epirubicin and esorubicin) were present in large amounts in the cells as the parent drug, another (idarubicin) as the 13-dihydro-derivative. This comparative study on cytotoxicity and metabolism of five anthracyclines in rat and human hepatocyte cultures emphasises species differences and the importance of this in vitro model system for further analysis of the metabolism and effect of anthracyclines.     

Continuous infusion of low-dose doxorubicin, epirubicin and mitoxantrone in cancer chemotherapy: A review

With the recent development of reliable portable pumps and safe venous access systems, continuous infusion of chemotherapeutic agents on an out-patient basis has become feasible. Advantages of continuous infusion are the long-term exposure of tumour cells to the drug and the fact that most toxic effects are reduced for doxorubicin, epirubicin and mitoxantrone due to elimination of the high peak plasma levels. Preliminary data for doxorubicin suggest that its antitumour activity is maintained. Pharmacokinetic studies with epirubicin and mitoxantrone showed a linear relationship between drug dose infused and the steady-state plasma level for these drugs. The area under the curve for leukocytes drug level was higher during continuous infusion than after an equitoxic bolus injection of epirubicin and mitoxantrone. Well-randomized clinical trials will be necessary to investigate the role of continuous infusion of antracyclines and mitoxantrone in cancer chemotherapy in the future.     

DNA拓扑异构酶Ⅱ抑制剂研究进展

在DNA复制。转录和有丝分裂等重要的生命过程中,拓扑异构酶Ⅱ是一种重要的酶。拓扑异构酶Ⅱ抑制剂是一种重要的药物,用于包括乳腺癌。肺癌,辛丸癌．淋巴瘤和肉瘤在内的多种恶性肿瘤的治疗。本文综述了几种拓扑异构酶Ⅱ抑制剂的作用机制,毒性,药理和临床应用,这些抑制剂包括依托泊苷。替尼泊苷,多柔比星,柔红霉素,表柔比星,伊达比星和米托蒽醌。本文将着重讲述关于这些药物以及拓扑异构酶Ⅱ抑制剂的发展情况的新信息。     

Anthraquinone-induced cell injury: acute toxicity of carminomycin, epirubicin, idarubicin and mitoxantrone in isolated cardiomyocytes.

Acute toxic effects of the antineoplastic anthraquinones carminomycin, epirubicin, idarubicin and mitoxantrone were studied in primary cultures of cardiomyocytes, which were isolated from adult rats. Both time- and concentration-dependent changes of cell structure and viability (trypan blue exclusion) following incubation of myocytes with subclinical, clinical and toxic concentrations of the anthraquinones were examined by light microscopy. The area under the decay curve of viable and rod-shaped myocytes was used to express cytotoxicity of the drugs. Mitoxantrone was found to reduce cell viability and number of rod-shaped cells to the greatest extent, followed by carminomycin, idarubicin and epirubicin. A significantly lower accumulation in cardiomyocytes was obtained with epirubicin and idarubicin compared with carminomycin. An inhibitory effect on oxygen consumption by the cells occurred already at 0.1 microM with epirubicin, whereas inhibition caused by other anthraquinones was less pronounced. Our data indicate a weak association of net accumulation and the toxicity parameter IC50 for carminomycin and idarubicin. In contrast to these results, a more significant correlation of cytotoxicity and anthraquinone lipophilicity was found, which suggests that the lipophilic character of a particular anthraquinone may be an important factor in drug-induced acute cardiotoxicity.     

Chemotherapy compounds in cervical cancer cells primed by reconstitution of p53 function after short interfering RNA-mediated degradation of human papillomavirus 18 E6 mRNA: opposite effect of siRNA in combination with different drugs

Constant expression of E6 and E7 mRNA by high-risk human papillomaviruses (HPV) abrogates p53 and retinoblastoma protein function, respectively, and is essential for the development of cervical cancer. Despite E6, some chemotherapy drugs can stabilize p53 in cervical cancer cells. It is not known how chemotherapy-induced p53 activation and cytotoxicity are affected when the amount of E6 mRNA is decreased before the drug treatment. In this study, HPV18-positive HeLa cervical cancer cells were transfected with short interfering RNA (siRNA) molecules targeting HPV18 E6 mRNA before treatment with carboplatin, cisplatin, doxorubicin, etoposide, gemcitabine, mitomycin, mitoxantrone, oxaliplatin, paclitaxel, and topotecan. Transfection with siRNA was followed by nuclear accumulation of p53, but the effect was transient despite continuously suppressed HPV mRNA levels. When treatment with E6 siRNA was coupled with chemotherapy, the p53 activity after treatment with carboplatin and paclitaxel was additively increased, whereas the p53 activation induced by the rest of the drugs was synergistically increased. Treatment with E6 siRNA alone moderately inhibited HeLa cell proliferation but did not induce detectable apoptosis. The combined cytotoxic effect of E6 siRNA and chemotherapy ranged from subadditive to synergistic, depending on the drug. The decrease of E6 mRNA sensitized HeLa cells, for example, to doxorubicin and gemcitabine but counteracted the cytotoxicity of cisplatin and etoposide. In conclusion, activating p53 by degrading E6 mRNA may either increase or decrease the chemosensitivity of cervical cancer cells, depending on the chemotherapy compound.     

In vitro assessment of cytotoxic agent combinations for hormone-refractory prostate cancer treatment

We have investigated new drug combinations of potential clinical value for treatment of hormone-refractory prostate cancer. Combinations of paclitaxel, carboplatin and mitoxantrone, and combinations of these three drugs with compounds targeting important pathways for cancer progression, 13-cis-retinoic acid and chelerythrine, were assessed. The drugs combinations were incubated for 72 h in steroid-free conditions with two androgen-independent cell lines, DU145 and PC3. Cytotoxicity assay was performed using resazurin and Hoescht 33342. Synergism and antagonism were measured by the combination index, and calculated for each combination by the median-effect method. All six compounds exhibited cytotoxic effects when tested alone. Paclitaxel exhibited the highest and 13-cis-retinoic acid the lowest effect on both cell lines. Paclitaxel demonstrated synergism or additivity with 13-cis-retinoic acid in both cell lines, whereas antagonistic effects were observed when it was tested in combination with carboplatin. Chelerythrine showed additive effects with mitoxantrone in both cell lines and with paclitaxel in PC3 cells. Our results suggest that combination of paclitaxel and 13-cis-retinoic acid, and of chelerythrine with mitoxantrone and paclitaxel, may have clinical value for the treatment of hormone-refractory prostate cancer.     

Transport of anthracyclines and mitoxantrone across membranes by a flip-flop mechanism

The objectives of the present work are to characterize the transport of mitoxantrone and three anthracyclines in terms of binding to the membrane surface, flip-flop across the lipid core of the membrane, and release into the medium. Mitoxantrone and anthracyclines are positively charged amphipathic molecules, and as such are located at the surface of membranes among the headgroups of the phospholipids. Therefore, their transport across membranes occurs by a flip-flop mechanism, rather than by diffusion down a continuous concentration gradient located in the lipid core of the membrane. Flip-flop rates have been estimated with liposomes labeled at their surface with 7-nitrobenzo-2-oxa-1,3-diazol-4-yl (NBD) moiety attached to the headgroup of phosphatidylethanolamine. Flip-flop of mitoxantrone, doxorubicin, daunorubicin, and idarubicin occurred with half-lives of 6, 0.7, 0.15, and 0.1min, respectively. Partition of the drugs into the membrane occurred with lipid phase/aqueous medium coefficients of 230,000, 8600, 23,000, and 40,000 for mitoxantrone, doxorubicin, daunorubicin, and idarubicin, respectively, which are much higher than their corresponding octanol/aqueous medium values. There was no direct correlation between the lipophilicity of the drugs and their lipid phase/aqueous medium partition coefficient or their flip-flop rate. Mitoxantrone exhibited the highest affinity toward liposome membranes, but the slowest flip-flop across the lipid core of the membranes. Simulation of drug uptake into liposomes revealed that transmembrane movement of the mitoxantrone and anthracyclines is determined by their flip-flop rate and affinity toward membranes.     

Chemotherapy waste reduction through shelf-life extension

Minimization of total drug expenditures within the health care system, without affecting patient outcome has become a rational goal in today's economic, environment. The objective of this study was to observe the effect of extending the shelf-life for three chemotherapy medications, [doxorubicin, epirubicin and mitoxantrone] on wastage of these medications. Prior to and following the introduction of new, longer, shelf-lives for these three medications, prospective, non-randomized, unblinded four-month chemotherapy wastage audits for all chemotherapy medications were completed at 18 institutional sites within Ontario (six Ontario Cancer Treatment and Research Foundation clinics, ten Ontario hospitals and two preparation sites in a large cancer treatment centre). Data were provided by 18 sites in 1989 but from only 12 sites in 1990. Ten of the 12 sites extended their shelf-lives for each of doxorubicin, epirubicin and mitoxantrone, and on average, waste at these sites was reduced to less than 1% of the 1989 total for epirubicin, less than 15% for doxorubicin and 35% for mitoxantrone. Many sites eliminated waste entirely for these drugs. For sites which did not extend their shelf-lives, the waste remained unchanged. We conclude that appropriate extension of the shelf-life for chemotherapy medications can reduce waste, and is a relatively simple method of reducing expenditures without affecting health outcomes or adding additional complications to IV chemotherapy.     

Intratumoral Pi deprivation benefits chemoembolization therapy via increased accumulation of intracellular doxorubicin

It is a decade-long controversy that transarterial chemoembolization (TACE) has definite priority over transarterial embolization (TAE) in treating patients with hepatocellular carcinoma (HCC), since HCC cells are regularly resistant to chemotherapy by enhanced expression of proteins that confer drug resistance, and ABC transporters pump the intracellular drug out of the cell. We addressed this issue by modulating the chemo-environment. In an animal model, sevelamer, a polymeric phosphate binder, was introduced as an embolic agent to induce intratumoral inorganic phosphate (Pi) starvation, and trans-arterially co-delivered with doxorubicin (DOX). The new type of TACE was named as DOX-TASE. This Pi-starved environment enhanced DOX tumoral accumulation and retention, and DOX-TASE thereby induced more severe tumor necrosis than that induced by conventional TACE (C-TACE) and drug-eluting bead TACE (D-TACE) at the same dose. In vitro tests showed that Pi starvation increased the cellular accumulation of DOX in an irreversible manner and enhanced cytotoxicity and cell apoptosis by suppressing the expression of ABC transporters (P-glycoprotein (P-gp), BCRP, and MRP1) and the production of intracellular ATP. Our results are indicative of an alternative interventional therapy combining chemotherapy with embolization more effectively.     

Preclinical evaluation of the cardiotoxicity of taxane-anthracycline combinations using the model of isolated perfused rat heart

Paclitaxel strongly potentiates the cardiotoxicity of doxorubicin in the clinical setting. In this study, we aimed (1) to determine whether this potentiation could be reproduced in an ex vivo model and, if so, (2) to select drugs and protocols that did not cause this potentiation. The effect of paclitaxel and docetaxel on the cardiotoxicity induced by doxorubicin and epirubicin was studied using the model of isolated perfused rat heart. Cardiac performances were evaluated after several combination protocols administered every 2 days over a period of 12 days, and anthracycline concentrations in the heart and liver were determined on Day 12. When administered simultaneously, paclitaxel strongly potentiated the cardiotoxicity of doxorubicin ex vivo, and this effect was not due to Cremophor EL, the solvent used in the formulation of paclitaxel. The potentiation of anthracycline cardiotoxicity could be avoided by the replacement of doxorubicin by epirubicin, and/or of paclitaxel by docetaxel. Cardiotoxic potentiation was also avoided by the introduction of a 24-h lag time between the repetitive injections of doxorubicin and docetaxel. The concentration of doxorubicin and its cardiotoxic metabolite, doxorubicinol, in the heart and liver was not significantly altered by the taxanes, but that of epirubicin was increased twofold both in the heart and the liver. These results show that the potentiation of doxorubicin-induced cardiotoxicity by paclitaxel can be reproduced with an ex vivo model, and that it is not related to an increase in tissue concentration of the drug or active metabolite. Our model, therefore, may be useful for the selection of anthracycline-containing protocols with no increased risk of cardiotoxicity for the patients.     

Liposomal doxorubicin and weekly paclitaxel in the treatment of metastatic breast cancer

The combination of paclitaxel and doxorubicin or epirubicin is highly active against metastatic breast cancer, yet may produce congestive heart failure. Liposome-encapsulated doxorubicin is a new formulation of doxorubicin with no dose-limiting cardiac toxicity. Twenty-one patients with metastatic breast cancer were treated with pegylated liposomal doxorubicin (20 mg/m2, day 1) and paclitaxel (100 mg/m2, days 1 and 8) for six cycles every 2 weeks. All patients had had relapse or progression on one to five previous chemotherapies. We observed two patients with complete and eight patients with partial remissions (48% response rate). Eight of the 10 responders had had previous therapy with epirubicin, doxorubicin or mitoxantrone. The mean remission duration was 5 months. Disease progression due to brain metastasis occurred in five cases. Severe side effects (grade 3 WHO) were alopecia (100%), skin toxicity in 29%, neuropathy in 24% and mucositis in 13%. Leukopenia (grade 4 WHO) was observed in 48%, but there was no cardiac toxicity, no death and no hospitalization. The combination of weekly paclitaxel and liposomal doxorubicin every 2 weeks is highly effective in previously treated patients. Based on the doses we administered, we recommend 15 mg/m2 liposomal doxorubicin every 2 weeks and 80 mg/m2 paclitaxel weekly.     

Hematological side-effect profiles of individualized chemotherapy regimen for recurrent ovarian cancer

The long-term results for patients with recurrent ovarian cancer (ROC) are poor. There is a need to optimize treatment strategies to improve outcome by avoiding ineffective regimens which are often associated with exacerbated side-effects. Individualized chemotherapy regimens guided by a chemosensitivity assay (ATP-tumor chemosensitivity assay) have already been used successfully to direct chemotherapy. Taking the results of this assay into account, application of drug combinations appears more advisable. Here we present a systematic evaluation of toxicities seen with individualized chemotherapy for ROC. A total of 62 patients who received 314 cycles of antineoplastic therapies were evaluated. Three single agents (topotecan, paclitaxel and gemcitabine) and five combinations (cisplatin/gemcitabine, carbopatin/gemcitabine, gemcitabine/treosulfan, mitoxantrone/paclitaxel and carboplatin/paclitaxel) were examined. With respect to myelotoxicity, most single agents except topotecan revealed favorable results in comparison to drug combinations. However, this observation lacks statistical significance. Generally, severe myelosuppression was rare. The highest incidence of leukopenia was seen in regimens with mitoxantrone/paclitaxel or gemcitabine/treosulfan, respectively. Thrombocytopenia accompanied most commonly a topotecan therapy. In the present study combination regimens tend to be more toxic than monotherapies. When response rates are comparable, empirically chosen treatment combination therapies should only be practiced in carefully planned clinical studies.     

Comparative cytotoxicity, DNA synthesis inhibition and drug incorporation of eight anthracyclines in a model of doxorubicin-sensitive and -resistant rat glioblastoma cells

We have compared the growth inhibition, DNA synthesis inhibition and cell incorporation of eight anthracyclines in a model of doxorubicin-sensitive and -resistant rat C6 glioblastoma cells. The anthracyclines studied were both the reference molecules (daunorubicin, doxorubicin) and the new drugs recently introduced in clinical use or in trials (epirubicin, idarubicin, pirarubicin, esorubicin, rubidazone, 4'-deoxy-4'-iododoxorubicin). We have shown that the in vitro growth inhibition was correlated with the LD50. The new anthracyclines were more potent than the reference drugs in the sensitive cells and the resistance patterns revealed a reduced cross resistance of idarubicin, pirarubicin and 4'-deoxy-4'-iododoxorubicin towards the doxorubicin-resistant line. DNA synthesis inhibition occurred for much higher doses than growth inhibition in sensitive cells, but for similar doses in resistant cells. This suggests that different mechanisms could be involved in the mechanism of growth inhibition in sensitive and resistant cells. For similar exposures, reduction of drug incorporation was a general feature in the resistant line when compared to the sensitive one. However, no correlation was shown, for the various drugs, between the reduction of incorporation and the resistance factor. Moreover, the intracellular concentration required for growth inhibition is much higher in resistant cells than in sensitive cells, suggesting that increased drug efflux might not be the only mechanism to explain drug resistance.     

Experimental study of dexrazoxane-anthracycline combinations using the model of isolated perfused rat heart

We have studied the protective effect of dexrazoxane on the cardiac toxicity induced by the anthracyclines currently used in clinics, doxorubicin, epirubicin, daunorubicin and idarubicin, with special emphasis on determining the optimal dose of dexrazoxane. This was performed using the model of isolated perfused rat heart after 12-day combination treatment of anthracyclines used at equi-cardiotoxic doses, and dexrazoxane used at 10-fold or 20-fold the anthracycline dose. We have shown in this study that dexrazoxane by itself was not cardiotoxic, and was able to significantly reduce anthracycline cardiac toxicity without increasing the general toxicity induced by these drugs. Using dexrazoxane at 20 times the anthracycline dose provided a better cardioprotection than using it at 10 times the anthracycline dose; at the higher dexrazoxane dose, the functional cardiac parameters (developed pressure, contractility and relaxation) were not different from those recorded in control animals.     

Multidrug resistance in cancer chemotherapy and xenobiotic protection mediated by the half ATP-binding cassette transporter ABCG2

ABCG2, also termed BCRP/MXR/ABCP, is a half ATP-binding cassette (ABC) transporter expressed on plasma membranes. ABCG2 was independently cloned from placenta as well as cell lines selected for resistance to mitoxantrone or anthracyclines. ABCG2 consists of a nucleotide-binding domain (NBD) at the amino terminus and a transmembrane domain (TMD) at the carboxyl terminus and it is postulated to form a homodimer to perform its biological functions. Over-expression of ABCG2 in cell lines confers resistance on a wide variety of anticancer drugs including mitoxantrone, daunorubicin, doxorubicin, topotecan and epirubicin. The expression of ABCG2 has been implicated in multidrug resistance (MDR) of acute myeloid leukemia and some solid tumors. In addition, ABCG2 can transport several fluorescent dyes or toxins. ABCG2 is found to be expressed in epithelial cells of intestine and colon, liver canaliculi, and renal tubules, where it serves to eliminate the plasma level of orally administered anticancer drugs as well as ingested toxins. ABCG2 is found to be highly expressed in placenta and the luminal surface of microvessel endothelium blood-brain barrier where it may play a role in limiting the penetration of drugs, such as topotecan from the maternal plasma into the fetus and from blood to brain. A variety of inhibitors for ABCG2 including GF120918 may prove useful for sensitizing cancer cells to chemotherapy or altering the distribution of orally administered drug substrates of ABCG2. Interestingly, ABCG2 is also expressed highly in hematopoietic stem cells. However, the function of ABCG2 in stem cells is currently unknown, although it may provide protection to stem cells from a variety of xenobiotics.     

Artesunate synergizes with sorafenib to induce ferroptosis in hepatocellular carcinoma

Sorafenib is the first-line medication for advanced hepatocellular carcinoma(HCC),but it can only extend limited survival.It is imperative to find a combination strategy to increase sorafenib efficacy.Artesunate is such a preferred candidate,because artesunate is clinically well-tolerated and more importantly both drugs can induce ferroptosis through different mechanisms.In this study we investigated the combined effect of sorafenib and artesunate in inducing ferroptosis of HCC and elucidated the involved molecular mechanisms.We showed that artesunate greatly enhanced the anticancer effects of low dose of sorafenib against Huh7,SNU-449,and SNU-182 HCC cell lines in vitro and against Huh7 cell xenograft model in Balb/c nude mice.The combination index method confirmed that the combined effect of sorafenib and artesunate was synergistic.Compared with the treatment with artesunate or sorafenib alone,combined treatment induced significantly exacerbated lipid peroxidation and ferroptosis,which was blocked by N-acetyl cysteine and ferroptosis inhibitors liproxstatin-1 and deferoxamine mesylate,but not by inhibitors of other types of cell death(z-VAD,necrostatin-1 and belnacasan).In Huh7 cells,we demonstrated that the combined treatment induced oxidative stress and lysosome-mediated ferritinophagy,two essential aspects of ferroptosis.Sorafenib at low dose mainly caused oxidative stress through mitochondrial impairments and SLC7A11-invovled glutathione depletion.Artesunate-induced lysosome activation synergized with sorafenib-mediated pro-oxidative effects by promoting sequential reactions including lysosomal cathepsin B/L activation,ferritin degradation,lipid peroxidation,and consequent ferroptosis.Taken together,artesunate could be repurposed to sensitize sorafenib in HCC treatment.The combined treatment can be easily translated into clinical applications.     

基于FAERS数据库的蒽环类药物不良事件信号挖掘研究

目的 通过挖掘美国食品药品监督管理局不良事件呈报系统（FAERS）数据库中关于蒽环类药物（多柔比星、多柔比星脂质体,表柔比星、伊达比星、柔红霉素、米托蒽醌）的相关数据,探讨该药潜在的不良反应（ADR）,为临床安全用药提供依据。方法 提取FAERS数据库中2017年第一季度至2021年第四季度共20个季度6种蒽环类药物的不良事件（ADE）数据,采用报告比值比法（ROR）和综合标准法（MHRA）进行信号挖掘。结果 共得到16 334例次以6种蒽环类药物为首要怀疑药物的ADE报告,检测得到1 654个有效ADR信号。其中,多柔比星（非脂质体,DOX）有效信号637个,多柔比星脂质体（PLD）有效信号441个,表柔比星（EPC）有效信号247个,柔红霉素（DAC）有效信号183个,伊达比星（IDC）有效信号87个,米托蒽醌（MT）有效信号59个。信号累及23个不同的系统器官分类（SOC）,不同蒽环类药物的ADE主要累及血液及淋巴系统疾病、感染及侵染类疾病、心脏器官疾病等SOC。结论 蒽环类药物常见ADR累及的主要系统具有差异性,且不同药物之间与各系统ADR的关联强度不同。临床应用蒽环类药物时需...     

Ascochlorin overcomes chemoresistance and regulates the plasticity of doxorubicin induced EMT via modulation of the NF-кB pathway in hepatocellular carcinoma

OBJECTIVE Doxorubicin-based therapy has been found to be not significantly effective for the treatment of advanced stage hepatocellular carcinomas(HCCs),which often undergo epithelial-mesenchymal transition(EMT)during tumor progression.Increasing evidence suggest(s)that epithelial cell transformation to mesenchymal state canenhance the ability to self-renew and confer greater resistance to the conventional chemotherapeutic drugs.The aim of this study was to examine the potential efficacyof ascochlorin,an isoprenoid antibiotic to overcome drug resistance induced by doxorubicin in HCC cell lines and to elucidate its underlying mechanism(s)of action.METHODS The effect of doxorubicin and ascochlorin on HCC cell lines was determined by MTT,Western blotting,immunofluorescence and NF-кB DNA binding assays.RESULTS Our results indicate that HCC cells that show a mesenchymal-like phenotype,are resistance to the doxorubicin therapy which directly correlated with an increased slug expression.We also observed that activation of NF-кB pathway plays an essential role in doxorubicin induced-chemoresistance and pharmacological inhibition of this pathway with ascochlorin can significantly reverse drug-induced invasion/migration and resistance in HCC cells.CONCLUSION Our results indicate that combination treatment of doxorubicin with ascochlorin has the potential to inhibit HCC growth and metastasis.     

Telomerase activity is not a key determinant of sensitivity to standard cytotoxic drugs in human esophageal carcinoma cell lines

The aim of the present study was to investigate if basal telomerase activity levels may predict sensitivity to cytotoxic drugs in a panel of human esophageal carcinoma cell lines. The TRAPeze telomerase detection assay was used to investigate telomerase activity in the cell lines. Cytotoxic drug sensitivity for 20 standard cytotoxic agents was assessed using the fluorometric microculture cytotoxicity assay (FMCA). Telomerase activity was detected in all cell lines with a broad range of activity levels. Drug sensitivity also varied considerably between the cell lines. Except for a P value towards a correlation between mitoxantrone and telomerase activity (P=0.054), no statistically significant correlation was found between telomerase activity levels and sensitivity to investigated drugs, including key drugs such as cisplatin (P=0.9), 5-fluorouracil (P=0.8) and doxorubicin (P=0.54). We therefore conclude that basal telomerase activity level is not a key determinant of sensitivity to standard cytotoxic drugs in esophageal carcinoma cell lines.