Anthracyclines in haematology: preclinical studies, toxicity and delivery systems

Dosing of 7 + 3 induction chemotherapy in a patient with acute myeloid leukemia (AML) and morbid obesity

INTRODUCTION

Traditional chemotherapy dosing is based on body surface area (BSA) using standard formulas, which can pose challenges in dosing patients at body weight extremes. Studies suggest that chemotherapy dosing according to actual body weight does not increase toxicity in obese patients and current guidelines recommend full weight-based dosing of chemotherapy regardless of body mass index (BMI). However, the dosing of anthracyclines in obese patients can be challenging given limitations in maximum cumulative dosage, particularly in those at very extreme BMI. In this case, we highlight the difficulties of dosing anthracycline-based induction chemotherapy in a patient with newly diagnosed acute myeloid leukemia (AML) and BMI >90 kg/m2.

CASE REPORT

A 40-year-old female with morbid obesity is diagnosed with AML (nucleophosmin 1 (NPMI) and isocitrate dehydrogenase-2 mutated, FMS-like tyrosine kinase 3-Internal tandem duplication negative).

MANAGEMENT AND OUTCOME

The patient was initiated on induction therapy with 7 + 3 with dose capping of BSA at 2.75 m2 (cytarabine 200 mg/m2 continuous infusion over 24 h for 7 days, plus daunorubicin 60 mg/m2 slow intravenous push for 3 days), followed by two cycles of high-dose cytarabine consolidation therapy using actual BSA. The patient achieved morphologic complete remission; however, measurable residual disease testing for NPM1 remained positive after induction therapy.

DISCUSSION

This case suggests that dose capping of anthracyclines in the treatment of newly diagnosed AML may be an effective and safe treatment alternative in those with extreme BMI elevations beyond what has been studied in the literature. Given the increasing incidence of morbid obesity, further studies are needed to confirm appropriate dosing of anthracycline-based regimens at upper BMI extremes (>60 kg/m2).

Quatramer™ Mediated Codelivery of PI3-Kδ/HDAC6 Dual Inhibitor Augments the Anti-Cancer Efficacy of Epirubicin in Breast Cancer

The disruption and overexpression of phosphatidylinositol 3-kinase (PI3K)-AKT signaling pathway in cancer results in tumor growth, metastasis, and survival. Treatment with common anthracyclines has confirmed cancer cells' dependence on PI3K pathway through overexpression of AKT. Moreover, combining HDAC inhibitor with anthracycline has shown the targeting of breast cancer stem cells. Therefore, it has been hypothesized that the co-delivery of PI3-Kδ/HDAC6 dual inhibitor with Epirubicin using polymeric nanoparticle could increase the anti-cancer treatment efficacy with reduced toxicity. Pluronic modified polylactic acid block copolymer (quatramer) was used for encapsulation of PI3-Kδ/HDAC6 and Epirubicin. The co-encapsulated nanoparticles, PI3-Kδ/HDAC6-Epi-NPs have shown size of 99±3 nm, PDI of 0.18±0.07 with a sustained and slow-release profile in non-physiological buffer (PBS, pH 7.4). The in-vitro cell proliferation inhibition studies done on 2D and 3D culture of breast cancer cell lines have confirmed the synergistic effect of PI3-Kδ/HDAC6-Epi-NPs with lower IC₅₀ values compared to PI3-Kδ/HDAC6-NPs and Epi-NPs. Additionally, intravenous twice a week treatment for three weeks with PI3-Kδ/HDAC6-Epi-NPs resulted in complete tumor eradication in the syngeneic breast tumor mice model. In comparison, the PI3-Kδ/HDAC6-NPs and Epi-NPs result in tumor growth inhibition of 15.86% and 81.59%, respectively. These studies predicted that clinical use of PI3-Kδ/HDAC6-Epi-NPs will be effective in breast cancer treatments.

CPX-351 (Vyxeos®) can cause severe rash in acute myeloid leukemia-A case report

CPX-351, a promising new agent for patients with treatment-related and secondary acute myeloid leukemia can lead to a severe whole-body rash. Although severe side effects are rare, treatment should be carefully monitored at specialized centers.

Circadian clock: a regulator of the immunity in cancer

The circadian clock is an endogenous timekeeper system that controls and optimizes biological processes, which are consistent with a master circadian clock and peripheral clocks and are controlled by various genes. Notably, the disruption of circadian clock genes has been identified to affect a wide range of ailments, including cancers. The cancer-immunity cycle is composed of seven major steps, namely cancer cell antigen release and presentation, priming and activation of effector immunity cells, trafficking, and infiltration of immunity to tumors, and elimination of cancer cells. Existing evidence indicates that the circadian clock functions as a gate that govern many aspects of the cancer-immunity cycle. In this review, we highlight the importance of the circadian clock during tumorigenesis, and discuss the potential role of the circadian clock in the cancer-immunity cycle. A comprehensive understanding of the regulatory function of the circadian clock in the cancer-immunity cycle holds promise in developing new strategies for the treatment of cancer.

Tumor-specific lytic path “hyperploid progression mediated death”: Resolving side effects through targeting retinoblastoma or p53 mutant

A major advance was made to reduce the side effects of cancer therapy via the elucidation of the tumor-specific lytic path “hyperploid progression-mediated death” targeting retinoblastoma (Rb) or p53-mutants defective in G1 DNA damage checkpoint. The genetic basis of human cancers was uncovered through the cloning of the tumor suppressor Rb gene. It encodes a nuclear DNA-binding protein whose self-interaction is regulated by cyclin-dependent kinases. A 3D-structure of Rb dimer is shown, confirming its multimeric status. Rb assumes a central role in cell cycle regulation and the “Rb pathway” is universally inactivated in human cancers. Hyperploidy refers to a state in which cells contain one or more extra chromosomes. Hyperploid progression occurs due to continued cell-cycling without cytokinesis in G1 checkpoint-defective cancer cells. The evidence for the triggering of hyperploid progression-mediated death in RB-mutant human retinoblastoma cells is shown. Hence, the very genetic mutation that predisposes to cancer can be exploited to induce lethality. The discovery helped to establish the principle of targeted cytotoxic cancer therapy at the mechanistic level. By triggering the lytic path, targeted therapy with tumor specificity at the genetic level can be developed. It sets the stage for systematically eliminating side effects for cytotoxic cancer therapy.

Doxorubicin modulated clock genes and cytokines in macrophages extracted from tumor-bearing mice

Circadian rhythm is essential for cellular regulation of physiological, metabolic, and immune functions. Perturbations of circadian rhythms have been correlated with increased susceptibility to cancer and poor prognosis in the cancer treatment. Our aim is to investigate the role of doxorubicin (DOX) treatment on clock genes expression and inflammation in intraperitoneal macrophages and the antitumoral response. Methods: Macrophages were extracted from intraperitoneal cavity of mice without or with Lewis lung carcinoma (LLC) and treated with DOX totaling four groups (CTL, LLC, LLC+DOX and DOX) and analyzes of clock genes in six time points (ZT02, ZT06, ZT10, ZT14, ZT18 AND ZT22). Intraperitoneal macrophages cell culture was stimulated with LPS and DOX and clock genes and inflammatory profile were analyzed. In tumor were analyzed macrophages markers. Results: The expression of F4/80 (ZT22) and CD11c (ZT06) tumor tissue was significantly differed between LLC and LCC+DOX groups. In the intraperitoneal macrophages, DOX increased Clock (ZT10), Rev-Erbα (ZT18 and ZT22) and Per2 expressions (ZT18); in the LLC+DOX group was increased Bmal1 (ZT10), Per2 (ZT18) and NF-kB (ZT22) expressions; IL-6 expression increased in the LCC group (ZT02). In intraperitoneal macrophages cell culture stimulated with DOX and LPS after 24 h decreased Clock and Per1. DOX causes depression after 6 and 24 h in TNF-α content and Per2 gene expression after 24 h IL-1β expression was reduced also. Conclusion: DOX treatment in vivo disrupted cytokine and clock genes expression in intraperitoneal macrophages suppressing immune response. Moreover, macrophages cultured with DOX had decreased expression of LPS-stimulated inflammatory cytokines.

Evaluation of Micro-RNA Levels, Apoptosis and Oxidative Stress Markers in Patients Recieving Chemotherapy

OBJECTIVE

The primary objective of this study was to compare oxidative DNA damage markers, apoptosis markers and changes in miRNA levels in patients diagnosed with cancer and treated through chemotherapy. Our secondary objective was also to evaluate tumor responses that can be determined after post-chemotherapy clinical evaluations by physical examinations, laboratory results and radiological imagings, and to compare the clinical results to oxidative stress and apoptosis markers and micro RNA levels.

MATERIALS AND METHODS

To do that we designed a prospective observational cross-sectional study. A total of 34 cancer patients and 27 healthy controls were included in the study from the Harran University School of Medicine Department of Oncology. Newly diagnosed chemotherapy or radiotherapy naive patients without any chronic diseases were included into the study. Patients with a poor performance status (ECOG 2 and 3) and patients who did not meet the inclusion criteria were excluded. The cancer patients received chemotherapy according to their scheduled periods. Blood samples were taken from the patients before the first chemotherapy course and before the second chemotherapy round. Patients were called for toxicity control on the 10th day after the chemotherapy. Pre-chemotherapy, post-chemotherapy and control group miR-29a expression levels, change in apoptosis markers and oxidative DNA damage markers were obtained and compared. We studied 8-hydroxy 2-deoxyguanosine, total oxidant status, total anti-oxidant status, and oxidative status index for oxidative stress markers. We studied M30 and M65 as apoptosis markers. Clinical results of efficiency of the chemotherapy was acquired and compared to biochemical markers based on chemotherapy results. Chemotherapy toxicities were recorded.

RESULTS

As a result, we found oxidative DNA damage markers and apoptosis markers were high in the cancer group, demonstrating that oxidative DNA damage and apoptosis might play a direct or indirect role in cancer etiology. However, there were subtle differences between pre-chemotherapy and post-chemotherapy levels. Mir-29a expressions were lower in cancer patients as compared to controls. However, the expression levels were not significantly change in pre- and postchemotherapy status. Moreover, we found no relationship between clinical status of patients (progression and regression) and studied biochemical markers.

CONCLUSION

Thus, checking for DNA damage markers and taking precautions to lower the levels of these markers in individuals with cancer risk may be helpful in preventing cancer.

Drug eruptions associated with tumor therapy: Great imitators

Many studies have investigated cutaneous reactions to antitumor drugs and found them to be quite numerous. We describe drug eruptions that may be associated with different therapies by class: antimetabolite chemotherapeutics, genotoxic agents, spindle inhibitors, signal transduction inhibitors, and immunotherapies. Methotrexate is most often associated with mucocutaneous reactions, alkylating antimetabolite agents with hyperpigmentation, and platinum antimetabolite agents with type I IgE-mediated hypersensitivity reactions. Anthracycline derivatives can induce the hand-foot syndrome in patients, and bleomycin is associated with a bleomycin-induced flagellate erythema. Taxane spindle inhibitors can result in acneiform eruptions, which may also be seen with use of epidermal growth factor receptor inhibitors. Imatinib and its derivatives can cause a truncal maculopapular eruption, whereas multikinase inhibitors can produce a hand-foot-skin reaction. Vemurafenib can result in squamous cell carcinomas and photosensitivity. First-generation mammalian target of rapamycin inhibitors may cause a maculopapular eruption initially involving the face and neck. Programmed death (PD)-1-ligand and receptor inhibitors are associated with bullous pemphigoid. Ipilimumab, targeting Cytotoxic -T- Lymphocyte- associated (CTLA-4) receptors, can cause a morbilliform reaction, whereas Interleukin -2 (IL-2) analogs can create the capillary leak syndrome. Chemotherapeutic drug eruptions classically can manifest in the aforementioned ways; however, it is important to understand that they are associated with myriad cutaneous adverse effects, which may be mistaken for organic skin disease. Oncologists prescribing these medications should be familiar with the cutaneous side effects of these medications, and so they may counsel patients to be on the lookout for them.

Clinical utility of miR-143/miR-182 levels in prognosis and risk stratification specificity of BFM-treated childhood acute lymphoblastic leukemia

Although childhood acute lymphoblastic leukemia (ALL) is characterized by high remission rates, there are still patients who experience poor response to therapy or toxic effects due to intensive treatment. In the present study, we examined the expression profile of miR-143 and miR-182 in childhood ALL and evaluated their clinical significance for patients receiving Berlin-Frankfurt-Münster (BFM) protocol. Bone marrow specimens from 125 childhood ALL patients upon diagnosis and the end-of-induction (EoI; day 33), as well as from 64 healthy control children undergone RNA extraction, polyadenylation, and reverse transcription. Expression levels of miRNAs were quantified by qPCR analysis. Patients' cytogenetic, immunohistotype and MRD evaluation was performed according to international guidelines. Median follow-up time was 86.0 months (95% CI 74.0-98.0), while patients' mean DFS and OS intervals were 112.0 months (95% CI 104.2-119.8) and 109.2 months (95% CI 101.2-117.3), respectively. Bone marrow levels of miR-143/miR-182 were significantly decreased in childhood ALL patients at diagnosis and increased in more than 90% of patients at the EoI. Patients' survival analysis highlighted that children overexpressing miR-143/miR-182 at the EoI presented significantly higher risk for short-term relapse (log-rank test: p = 0.021; Cox regression: HR = 4.911, p = 0.038) and death (log-rank test: p = 0.028; Cox regression: HR = 4.590, p = 0.046). Finally, the evaluation of the miR-143/miR-182 EoI levels along with the established disease prognostic markers resulted to improved prediction of BFM-treated patients' survival outcome and response to therapy and additionally to superior BFM risk stratification specificity. Concluding, miR-143 and miR-182 could serve as novel prognostic molecular markers for pediatric ALL treated with BFM chemotherapy.

miR-125b predicts childhood acute lymphoblastic leukaemia poor response to BFM chemotherapy treatment

BACKGROUND

Despite the favourable survival rates of childhood acute lymphoblastic leukaemia (ALL), a significant number of patients present resistance to antileukaemic agents and dismal prognosis. In this study, we analysed miR-125b expression in childhood ALL and evaluated its clinical utility for patients treated with Berlin-Frankfurt-Münster (BFM) protocol.

METHODS

The study included 272 bone marrow specimens obtained on diagnosis and on BFM day 33 from 125 patients and 64 healthy children. Following extraction, RNA was polyadenylated and reverse transcribed. miR-125b levels were quantified by quantitative PCR. Cytogenetics, immunohistotype and MRD were analysed according to international guidelines.

RESULTS

Downregulated miR-125b levels were detected in childhood ALL patients and correlated with adverse prognosis. Following BFM induction, miR-125b levels were significantly increased, however, elevated day 33/diagnosis miR-125b ratio was associated with unfavourable disease features. Loss of miR-125b during diagnosis and higher day 33/diagnosis ratio were correlated with stronger risk for disease short-term relapse and patients' worse survival. Moreover, multivariate regression models highlighted the independent prognostic value of miR-125b for childhood ALL. Finally, the combination of miR-125b with clinically used disease markers clearly enhanced the prediction of patients' resistance to BFM chemotherapy.

CONCLUSIONS

miR-125b significantly improves the prognosis of childhood ALL patients' outcome under BFM treatment.

Doxorubicin caused severe hyperglycaemia and insulin resistance, mediated by inhibition in AMPk signalling in skeletal muscle

BACKGROUND

Cancer is considered the second leading cause of death in the world, and for the treatment of this disease, pharmacological intervention strategies are frequently based on chemotherapy. Doxorubicin (DOX) is one of the most widely used chemotherapeutic agents in clinical practice for treating a number of solid tumours. The treatment with DOX mimics some effects of cancer cachexia, such as anorexia, asthenia, decreases in fat and skeletal muscle mass and fatigue. We observed that treatment with DOX increased the systemic insulin resistance and caused a massive increase in glucose levels in serum. Skeletal muscle is a major tissue responsible for glucose uptake, and the positive role of AMPk protein (AMP-activated protein kinase) in GLUT-4 (Glucose Transporter type 4) translocation, is well established. With this, our aim was to assess the insulin sensitivity after treatment with DOX and involvement of AMPk signalling in skeletal muscle in this process.

METHODS

We used Wistar rats which received a single dose of doxorubicin (DOX group) or saline (CT group) intraperitoneally at a dose of 15 mg/kg b.w. The expression of proteins involved in insulin sensitivity, glucose uptake, inflammation, and activity of electron transport chain was assessed in extensor digitorum longus muscle, as well as the histological evaluation. In vitro assays were performed in L6 myocytes to assess glucose uptake after treatment with DOX. Agonist of AMPk [5-aminoimidazole-4-carboxamide (AICAR)] and the antioxidant n-acetyl cysteine were used in L6 cells to evaluate its effect on glucose uptake and cell viability.

RESULTS

The animals showed a significant insulin resistance, hyperglycaemia, and hyperinsulinemia. A decrease in the expression of AMKP and GLUT-4 was observed in the extensor digitorum longus muscle. Also in L6 cells, DOX leads to a decrease in glucose uptake, which is reversed with AICAR.

CONCLUSIONS

DOX leads to conditions similar to cachexia, with severe glucose intolerance both in vivo and in vitro. The decrease of AMPk activity of the protein is modulated negatively with DOX, and treatment with agonist of AMPk (AICAR) has proved to be a possible therapeutic target, which is able to recover glucose sensitivity in skeletal muscle.

Histopathologic Features Seen with Radiation Recall or Enhancement Eruptions

Background:

Although a radiation recall or enhancement eruption has been associated with a number of chemotherapeutic drugs, the histologic features have rarely been described.

Objective:

Our goal was to define the histologic features of radiation recall and enhancement eruptions in order to better understand their pathogenesis.

Methods:

We present ten patients on chemotherapeutic agents who developed erythematous maculopapular to psoriasiform eruptions often with associated follicular pustules. These eruptions occurred at the sites of prior or concurrent radiation therapy.

Results:

The most common class of drugs inducing these reactions were antibiotic chemotherapeutic agents alone or in combination with other chemotherapeutic drugs. In addition to routine histology, in four patients immunohistochemical staining for p53 was performed at the sites of the eruptions after resolution and at noninvolved sites matched for ultraviolet radiation (UVR) exposure. Histologic features in patients receiving concurrent radiation therapy included epidermal dysplasia, keratinocytes showing features of necrosis, increased mitotic figures, and a mixed inflammatory infiltrate. At sites of prior radiation therapy, the biopsy specimens showed a similar spectrum of epidermal changes and, in some cases, psoriasiform dermatitis with clearing within cells in the upper layers of the epidermis. Additional dermal changes included dermal fibrosis, vasodilatation, and atypical fibroblasts. Moderate to marked solar elastosis was seen in the majority of biopsy specimens. Immunohistochemical studies after resolution showed only a modest increase in p53 staining in epidermal keratinocytes in 3 of 4 sites of recall and enhancement eruptions after resolution of the reactions compared to skin that was matched for similar UVR exposure.

Conclusion:

Cumulative direct DNA damage and oxidative stress are probably important in radiation recall and enhancement eruptions, and these changes may be modulated by underlying nutritional deficits. Cumulative p53 mutations may play some role but are probably not a major factor in these eruptions. Mitochondrial dysfunction, which is known to occur with prior and concurrent radiation and chemotherapy, may be important in these eruptions. In addition to improvements in general nutrition, topical or oral antioxidant therapy may be a potential therapy to avoid radiation enhancement and recall reactions.

Technetium Tc 99m sulfur colloid phenotypic probe for the pharmacokinetics and pharmacodynamics of PEGylated liposomal doxorubicin in women with ovarian cancer

PURPOSE

Significant variability in the pharmacokinetics and pharmacodynamics of PEGylated liposomal doxorubicin (PLD) exists. PLD undergoes clearance via the mononuclear phagocyte system (MPS). Technetium Tc 99m sulfur colloid (TSC) is approved for imaging MPS cells. We investigated TSC as a phenotypic probe of PLD pharmacokinetics and pharmacodynamics in women with epithelial ovarian cancer.

METHODS

TSC 10 mCi IVP was administered and followed by dynamic planar and SPECT/CT imaging and blood pharmacokinetics sampling. PLD 30-40 mg/m(2) IV was administered with or without carboplatin, followed by plasma pharmacokinetics sampling.

RESULTS

There was a linear relationship between TSC clearance and encapsulated doxorubicin clearance (R(2) = 0.61, p = 0.02), particularly in patients receiving PLD alone (R(2) = 0.81, p = 0.04). There was a positive relationship (ρ = 0.81, p = 0.01) between maximum grade palmar-plantar erythrodysesthesia toxicity developed and estimated encapsulated doxorubicin concentration in hands.

CONCLUSIONS

TSC is a phenotypic probe for PLD pharmacokinetics and pharmacodynamics and may be used to individualize PLD therapy in ovarian cancer and for other nanoparticles in development.

miR-181a modulates acute myeloid leukemia susceptibility to natural killer cells

Although daunorubicin (DNR) is the most widely used anthracycline to treat acute myeloid leukemia (AML), resistance to this drug remains a critical problem. The aim of this study was to investigate the relationship between AML resistance to daunorubicin and susceptibility to natural killer (NK) cell-mediated cell lysis, and the putative expression of miRs. For this purpose, we used the parental AML cell lines U-937 and KG-1 and their equivalent resistant U937(R) and KG-1(R) cell lines. We demonstrate for the first time that the acquisition of resistance to DNR by the parental cell lines resulted in the acquisition of cross-resistance to NK cell-mediated cytotoxicity. miR microarray analysis revealed that this cross-resistance was associated with miR-181a downregulation and the subsequent regulation of MAP3K10 and MAP2K1 tyrosine kinases and the BCL^-2 (BCL^-2 and MCL^-1) family. Overexpression of miR-181a in AML blasts resulted in the attenuation of their resistance to DNR and to NK-cell-mediated killing. These data point to a determinant role of miR-181a in the sensitization of leukemic resistant cells to DNR and NK cells and suggest that miR-181a may provide a promising option for the treatment of immuno- and chemo-resistant blasts.

Combination of glycosphingosomes and liposomal doxorubicin shows increased activity against dimethyl-α-benzanthracene-induced fibrosarcoma in mice

The present study aimed to assess the antitumor effect of glycosphingolipid-incorporated liposomes (glycosphingosomes) in combination with liposomal doxorubicin (Lip-Dox) in a mouse model of fibrosarcoma. Glycosphingosomes were prepared by incorporating glycosphingolipids isolated from Sphingomonas paucimobilis into the liposomes of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, cholesterol, and cardiolipin. Tumors were induced by administering dimethyl-α-benzanthracene, and tumor-bearing mice were treated with various formulations of Dox, including free Dox, Lip-Dox, or glycosphingosomes + Lip-Dox. Mice were observed for 90 days to monitor their survival and tumor size. Free Dox, but not Lip-Dox or a combination of glycosphingosomes and Lip-Dox, caused the substantial depletion of leukocytes and significantly increased the levels of lactate dehydrogenase and creatinine kinase in mice. Tumor-bearing mice treated with a combination of glycosphingosomes and Lip-Dox showed restricted tumor growth and increased survival when compared to those treated with free Dox or Lip-Dox. The results of the present study suggest that a combination of glycosphingosomes and Lip-Dox may prove to be very effective in the treatment of tumors.

A folate modified pH sensitive targeted polymeric micelle alleviated systemic toxicity of doxorubicin (DOX) in multi-drug resistant tumor bearing mice

PURPOSE

The purpose of this work was to demonstrate the advantages of a folate modified pH sensitive micelle system (HPPF) on reducing the systemic toxicity of antitumor drug doxorubicin (DOX) as well as increasing the antitumor efficacy on multi-drug resistant tumor.

METHODS

The micelle HPPF was fabricated by PHIS-PEG and Fol-PEG-PLA using dialysis method. Multi-drug resistant human breast-cancer cell (MCF-7Adr) was used to test the therapeutic effect of DOX loaded HPPF micelles (HPPF/DOX). Nude mice bearing MCF-7Adr tumor was used to evaluate the systemic toxicity of HPPF/DOX.

RESULTS

The micelle HPPF was successfully prepared with good size uniformity and pH sensitivity. The in vitro experiments showed that HPPF significantly increased the intracellular level and cytotoxicity of DOX. The in vivo experiments demonstrated that HPPF had largely reduced the mortality and body weight loss, improved the animal status and decreased damages on heart and lung tissues comparing to free DOX.

CONCLUSIONS

The HPPF/DOX could significantly increase the antitumor efficacy of DOX and largely alleviate the systemic side effects induced by high dose DOX in the treatment of multi-drug resistant tumor.

Efficacy of mitoxantrone as frontline anthracycline during induction therapy in adults with newly diagnosed acute lymphoblastic leukemia: a single-center experience

Remission induction regimens for acute lymphoblastic leukemia (ALL) in adults induce complete remission (CR) in 60-90% and cure in 20-40%. A cohort study of newly diagnosed patients with ALL treated with mitoxantrone versus doxorubicin was conducted from 2005 to 2013. The primary endpoint was the proportion of CR. Eighty-five patients were included. Fifty-three received induction with doxorubicin and 32 with mitoxantrone. Median follow-up in the cohort was 40.2 months (range 2-95). Twenty-nine patients (90.6%) achieved CR in the mitoxantrone arm compared with 37 (69.8%) in the doxorubicin group (p = 0.032). There was no difference in death or relapse rate (p = 0.095 and 0.075), hematological recovery (p = 0.654), incidence of adverse events (p = 0.6), in-hospital days during induction (p = 0.456) or overall survival (p = 0.105). Induction toxicities were comparable. Mitoxantrone can be safely and effectively used as a frontline anthracycline in adults newly diagnosed with ALL.

Dual-effect liposomes encapsulated with doxorubicin and chlorin e6 augment the therapeutic effect of tumor treatment

BACKGROUND AND OBJECTIVE

Long circulating doxorubicin (Dox)-loaded PEGylated liposomes are clinically safer than the free form due to the significant reduction of cardiac toxicity. However, the therapeutic efficacy of the PEGylated liposome could further be improved if poor diffusivity and slow drug release of the liposome in tumor interstitium can be overcome. In this study, a dual-effect liposome triggered by photodynamic effect was developed to improve the therapeutic efficacy of Dox-loaded PEGylated liposomes.

MATERIALS AND METHODS

Dox and chlorin e6 (Ce6) were co-encapsulated in PEGylated liposomes (named as PL-Dox-Ce6). To induce the drug release, photodynamic effect was triggered by the light irradiation of a 662 nm diode laser. The cellular distribution of Dox and Ce6 was examined under confocal microscope. The in vitro and in vivo cytotoxicity of PL-Dox-Ce6 was determined via the colony formation assay and the synergistic C26 tumor model, respectively.

RESULTS

The cellular distribution of PL-Dox-Ce6 was in the cytoplasmic area; while under light irradiation, Dox was co-localized with nuclear staining positive signals. The cellular cytotoxicity of PL-Dox-Ce6 was significantly higher than the controls including liposomes encapsulating either Dox (PL-Dox) or Ce6 (PL-Ce6). The in vivo treatment efficacy of PL-Dox-Ce6 determined in the C26 tumor model reveals a significant therapeutic effect compared to that of PL-Ce6 and PL-Dox alone or in combination.

CONCLUSION

This study indicates that this dual-effect PEGylated liposome could provide clinical advantages in the combination regimen of photodynamic therapy and chemotherapy.

microRNA‑125b promotes leukemia cell resistance to daunorubicin by inhibiting apoptosis

microRNA-125b (miR-125b) is overexpressed in several types of cancer and contributes to tumor resistance to chemotherapy. The present study investigated the effect of miR-125b on the resistance of leukemia cell lines to the chemotherapeutic agent daunorubicin (DNR). miR-125b expression was found to be upregulated in patients who had failed therapy compared with those who demonstrated event-free survival. The overexpression of miR-125b was observed to induce DNR resistance in K562, THP‑1 and Jurkat cells by reducing apoptosis, whereas the suppression of miR-125b was found to enhance DNR cytotoxicity in REH cells. Furthermore, miR-125b was observed to mediate DNR resistance in leukemia cell lines through decreasing expression of G protein-coupled receptor kinase 2 and p53-upregulated modulator of apoptosis, which were shown to be direct targets of miR-125b using a dual-luciferase reporter. The present study provides a novel mechanism for understanding leukemia drug resistance and provides a novel method for calculating patient prognosis.

Management of cytotoxic extravasation - ASORS expert opinion for diagnosis, prevention and treatment

BACKGROUND

Cytotoxic extravasation is a rare but potentially serious and painful complication of intravenous drug administration in oncology. Literature is anecdotal, and systematic clinical trials are scarce. The German working group for Supportive Care in Cancer (ASORS) has prepared an expert opinion for the diagnosis, prophylaxis and management of cytotoxic extravasation based on an interdisciplinary expert panel.

MATERIAL AND METHODS

A Pubmed search was conducted for diagnosis, risk factors, symptoms, prophylaxis, and treatment of extravasation by the respective responsible expert. A writing committee compiled the manuscript and proposed the level of recommendation. In a consensus meeting, 13 experts reviewed and discussed the current practice in diagnosis and management of cytotoxic extravasation. In a telephone voting among the experts, the level of recommendation by ASORS was determined.

RESULTS

Every effort should be made to reduce the risk of extravasation. Staff training, patient education, usage of right materials and infusion techniques have been identified to be mandatory to minimalize the risk of extravasation. Extravasation must be diagnosed as soon as possible, and specific therapy including antidotes dependent on the extravasated drug should be initiated immediately. An extravasation emergency set should be available wherever intravenous cytotoxics are applied. Documentation and post-treatment follow-up are recommended.

CONCLUSION

We have developed a literature- and expert-based consensus recommendation to avoid cytotoxic extravasation. It also provides practical management instructions which should help to avoid surgery and serious late effects.

Immunologic consequences of chemotherapy for acute myeloid leukemia

There are few data characterizing the immunologic consequences of chemotherapy for acute myeloid leukemia (AML) and almost nothing is known about the effects of chemotherapy in a pediatric AML cohort. We identified T-cell subsets, B-cell subsets, and used Enzyme-linked immunosorbent spot analyses to define the function of T cells and B cells in 7 pediatric patients with AML on chemotherapy. The data show that the effects of chemotherapy disproportionately target the B cell and depletion of B cells is associated with impaired responses to the inactivated influenza vaccine. Diminished T-cell numbers were also observed although the magnitude of the effect was less than what was seen for B cells. Furthermore, measures of T-cell function were largely intact. We conclude that humoral immunity is significantly affected by chemotherapy for AML.

Alendronate-conjugated amphiphilic hyperbranched polymer based on Boltorn H40 and poly(ethylene glycol) for bone-targeted drug delivery

A novel type of alendronate(ALE)-conjugated amphiphilic hyperbranched copolymer based on a hydrophobic hyperbranched Boltorn H40 (H40) core with ALE targeting moiety and many hydrophilic poly(ethylene glycol) (PEG) arms was synthesized as a carrier for bone-targeted drug delivery. The star copolymer H40-star-PEG/ALE was characterized using nuclear magnetic resonance (NMR), Fourier transformed infrared spectroscopy (FTIR), and gel permeation chromatography (GPC) analysis. Benefiting from its highly branched structure, H40-star-PEG/ALE could form micelles in aqueous solution, which was confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The cytotoxicity and hemolysis of the H40-star-PEG/ALE micelles were evaluated via methylthiazoletetrazolium (MTT) assay against NIH/3T3 normal cells and red blood cell (RBC) lysis assay, respectively. As a model anticancer drug, doxorubicin (DOX) was encapsulated into the H40-star-PEG/ALE micelles. The anticancer activity of DOX-loaded micelles was evaluated by MTT assay against an HN-6 human head and neck carcinoma cell line. The strong affinity of H40-star-PEG/ALE micelles to bone was confirmed by the hydroxyapatite (HA) binding assay. These results indicate that the H40-star-PEG/ALE micelles are highly promising bone-targeted drug carriers for skeletal metastases.

The opposite effects of doxorubicin on bone marrow stem cells versus breast cancer stem cells depend on glucosylceramide synthase

Myelosuppression and drug resistance are common adverse effects in cancer patients with chemotherapy, and those severely limit the therapeutic efficacy and lead treatment failure. It is unclear by which cellular mechanism anticancer drugs suppress bone marrow, while drug-resistant tumors survive. We report that due to the difference of glucosylceramide synthase (GCS), catalyzing ceramide glycosylation, doxorubicin (Dox) eliminates bone marrow stem cells (BMSCs) and expands breast cancer stem cells (BCSCs). It was found that Dox decreased the numbers of BMSCs (ABCG2(+)) and the sphere formation in a dose-dependent fashion in isolated bone marrow cells. In tumor-bearing mice, Dox treatments (5mg/kg, 6 days) decreased the numbers of BMSCs and white blood cells; conversely, those treatments increased the numbers of BCSCs (CD24(-)/CD44(+)/ESA(+)) more than threefold in the same mice. Furthermore, therapeutic-dose of Dox (1mg/kg/week, 42 days) decreased the numbers of BMSCs while it increased BCSCs in vivo. Breast cancer cells, rather than bone marrow cells, highly expressed GCS, which was induced by Dox and correlated with BCSC pluripotency. These results indicate that Dox may have opposite effects, suppressing BMSCs versus expanding BCSCs, and GCS is one determinant of the differentiated responsiveness of bone marrow and cancer cells.

High TOP2B/TOP2A expression ratio at diagnosis correlates with favourable outcome for standard chemotherapy in acute myeloid leukaemia

Background:

Cytosine arabinoside-based chemotherapy coupled with anthracycline is currently the first-line treatment for acute myeloid leukaemia (AML), but diverse responses to the regimen constitute obstacles to successful treatment. Therefore, outcome prediction to chemotherapy at diagnosis is believed to be a critical consideration.

Methods:

The mRNA expression of 12 genes closely involved in the actions of cytosine arabinoside and anthracycline was evaluated by real-time reverse transcriptase PCR (RT–PCR), in 54 diagnostic bone marrow specimens of M2-subtype AML.

Results:

Low expression levels of ribonucleotide reductase M2 (RRM2) and high expression levels of topoisomerase 2 beta (TOP2B) were correlated with longer survival in a univariate analysis. Another interesting finding is that high ratios of TOP2B/RRM2 and TOP2B/TOP2 alpha (TOP2A) in a combined analysis were also shown to have a prognostic impact for longer survival with improved accuracy. Among the four markers, when adjusted for the influence of other clinical factors in multivariate analysis, the TOP2B/TOP2A ratio was significantly correlated with treatment outcomes; patients with high ratios trended toward longer disease-free survival (HR, 0.24; P=0.002) and overall survival (HR, 0.29; P=0.005).

Conclusion:

Genes with distinct expression profiles such as TOP2B/TOP2A expression ratio at diagnosis can be employed for outcome prediction after the treatment with standard regimens in AML patients with M2 subtype.

Rationally engineered nanoparticles target multiple myeloma cells, overcome cell-adhesion-mediated drug resistance, and show enhanced efficacy in vivo

In the continuing search for effective cancer treatments, we report the rational engineering of a multifunctional nanoparticle that combines traditional chemotherapy with cell targeting and anti-adhesion functionalities. Very late antigen-4 (VLA-4) mediated adhesion of multiple myeloma (MM) cells to bone marrow stroma confers MM cells with cell-adhesion-mediated drug resistance (CAM-DR). In our design, we used micellar nanoparticles as dynamic self-assembling scaffolds to present VLA-4-antagonist peptides and doxorubicin (Dox) conjugates, simultaneously, to selectively target MM cells and to overcome CAM-DR. Dox was conjugated to the nanoparticles through an acid-sensitive hydrazone bond. VLA-4-antagonist peptides were conjugated via a multifaceted synthetic procedure for generating precisely controlled number of targeting functionalities. The nanoparticles were efficiently internalized by MM cells and induced cytotoxicity. Mechanistic studies revealed that nanoparticles induced DNA double-strand breaks and apoptosis in MM cells. Importantly, multifunctional nanoparticles overcame CAM-DR, and were more efficacious than Dox when MM cells were cultured on fibronectin-coated plates. Finally, in a MM xenograft model, nanoparticles preferentially homed to MM tumors with ∼10 fold more drug accumulation and demonstrated dramatic tumor growth inhibition with a reduced overall systemic toxicity. Altogether, we demonstrate the disease driven engineering of a nanoparticle-based drug delivery system, enabling the model of an integrative approach in the treatment of MM.

Haemotoxicity of busulphan, doxorubicin, cisplatin and cyclophosphamide in the female BALB/c mouse using a brief regimen of drug administration

Many anticancer drugs are myelotoxic and cause bone marrow depression; however, generally, the marrow/blood returns to normal after treatment. Nevertheless, after the administration of some anti-neoplastic agents (e.g. busulphan, BU) under conditions as yet undefined, the marrow may begin a return towards normal, but normality may not be achieved, and late-stage/residual marrow injury may be evident. The present studies were conducted to develop a short-term mouse model (a 'screen') to identify late-stage/residual marrow injury using a brief regimen of drug administration. Female BALB/c mice were treated with BU, doxorubicin (DOX), cisplatin (CISPLAT) or cyclophosphamide (CYCLOPHOS) on days 1, 3 and 5. In 'preliminary studies', a maximum tolerated dose (MTD) for each drug was determined for use in 'main studies'. In main studies, mice were treated with vehicle (control), low and high (the MTD) dose levels of each agent. Necropsies were performed, and blood parameters and femoral/humeral nucleated marrow cell counts (FNCC/HNCC) were assessed on six occasions (from days 1 to 60/61 post-dosing). Late-stage/residual changes were apparent in BU-treated mice at day 61 post-dosing: RBC, Hb and haematocrit were reduced, mean cell volume/mean cell haemoglobin were increased and platelet and FNCC counts were decreased. Mice given DOX, CISPLAT and CYCLOPHOS, in general, showed no clear late-stage/residual effects (day 60/61). It was concluded that a brief regimen of drug administration, at an MTD, with assessment at day 60/61 post-dosing was a suitable short-term method/screen in the mouse for detecting late-stage/residual marrow injury for BU, a drug shown to exhibit these effects in man.

Association of low tumor RNA integrity with response to chemotherapy in breast cancer patients

The CAN-NCIC-MA22 phase I/II clinical trial evaluated women with locally advanced or inflammatory breast cancer treated with epirubicin and docetaxel at 2 or 3 weekly intervals in sequential cohorts. The relationship between various biomarkers and treatment response was assessed. Breast biopsy cores were obtained from 50 patients pre-, mid-, and post-treatment. Immunohistochemical staining was performed to determine baseline levels of estrogen receptor (ER), progesterone receptor (PR), Her2/Neu protein (HER2), and topoisomerase II (Topo 2),expressed as percent positive stain. Tumor RNA integrity(RIN) and tumor cellularity were measured pre-, mid- and post-treatment by capillary electrophoresis and light microscopy after hematoxylin/eosin staining, respectively.Associations between 1) maximum RIN and 2) tumor cellularity at the three time points with baseline levels of ER,PR, Her2, and topo II were assessed using Spearman and Pearson correlation coefficients. Associations between RIN and tumor cellularity with chemotherapy dose level orpathologic response were assessed using one-way ANOVA.In this study, we observed that low mid-treatment maximum RIN (but not tumor cellularity) was associated with high chemotherapy drug dose level (P = 0.05) and eventual pathologic complete response (pCR) (P = 0.01). Posttreatment,low maximum RIN was found to be associated with low tumor cellularity (P = 0.004), and low tumor cellularity with pCR (P = 0.01). Post-treatment tumor cellularity was lowest in patients with tumors having high baseline PR levels (P = 0.05). The association of midtreatment RIN with drug dose level and with pCR suggests that tumor RIN may represent an important new biomarker for measuring response to chemotherapy in breast cancer patients.

Amelioration of doxorubicin-induced myocardial oxidative stress and immunosuppression by grape seed proanthocyanidins in tumour-bearing mice

We have investigated the protective effects of grape seed proanthocyanidins on doxorubicin-induced toxicity in tumour-bearing mice. The intraperitoneal administration of doxorubicin (2 mg kg−1 every other day, cumulative dosage for 18 mg kg−1) significantly inhibited the growth of sarcoma 180, and induced myocardial oxidative stress with decreased superoxide dismutase and glutathione peroxidase activity while increasing malondialdehyde formation in the heart or serum. Doxorubicin-induced myocardial oxidative stress also reduced lactate dehydrogenase and creatine kinase activity in the heart and elevated their levels in the serum. Doxorubicin also affected immune functions of tumour-bearing mice with significantly decreased interleukin-2 (IL-2) and interferon-γ (INF-γ) production, and slightly decreased natural killer (NK) cell cytotoxicity, lymphocyte proliferation and CD4+/CD8+ ratio. It markedly increased the percentages of cytotoxic T cells (CD3+CD8+), helper T cells (CD3+CD4+), IL-2R+CD4+, and IL-2R+ cells as compared with untreated tumour-bearing mice. The intragastric administration of proanthocyanidin (200 mg kg−1 daily) significantly inhibited tumour growth, and increased NK cell cytotoxicity, lymphocyte proliferation, CD4+/CD8+ ratio, IL-2 and INF-γ production. Moreover, proanthocyanidin strongly enhanced the anti-tumour effect of doxorubicin and the above immune responses, and completely eliminated myocardial oxidative stress induced by doxorubicin. In conclusion, intragastric administration of proanthocyanidin could enhance the anti-tumour activity of doxorubicin and ameliorate doxorubicin-induced myocardial oxidative stress and immunosuppression in tumour-bearing mice.

New agents in acute myeloid leukemia: beyond cytarabine and anthracyclines

The standard therapeutic approaches for acute myeloid leukemia (AML) continue to be based on anthracyclines and cytarabine. However, the prognosis for AML remains poor, especially for patients with high-risk disease. During the past decade, promising novel agents that target DNA replication and repair, as well as cell cycling and apoptosis, have been developed and are being actively investigated in AML. Among these agents is flavopiridol, which interferes with key steps of the cell cycle and effectively promotes cell death, and voreloxin, an intercalating agent that also targets topoisomerase II. Also under clinical study in AML are oligonucleotide antisense constructs, which suppress the translation of proteins essential for leukemic blast survival and proliferation, and agents that target antiapoptotic cascades. In summary, it is hoped that novel therapies such as these will augment and/or supplant our current cytarabine- and anthracycline-based approaches, overcome active drug-resistance pathways, and eventually improve outcomes for patients with AML.

Improving the therapeutic index of anthracycline chemotherapy: focus on liposomal doxorubicin (Myocet)

Anthracyclines are valuable cytotoxic agents in cancer treatment. However, their usefulness is limited by cumulative dose-dependent cardiotoxicity that may manifest as life-threatening congestive heart failure. To avoid cardiotoxicity, the use of doxorubicin is typically capped at a safe cumulative dose. Liposomal formulations may reduce cardiac risks whilst maintaining anti-cancer efficacy. Efficacy and safety studies of non-pegylated liposomal doxorubicin (NPLD) in metastatic breast cancer (MBC) are reviewed, along with studies that examine efficacy and cardiac tolerability in combination with newer agents such as paclitaxel and trastuzumab. These show that cardiac safety of liposomal doxorubicin is similar to that of epirubicin in cumulative dose, but that the formulation, unlike epirubicin, has similar anti-cancer efficacy to doxorubicin at equimolar doses. Liposomal doxorubicin may have a better therapeutic index than non-liposomal anthracyclines. This justifies further studies in patients where cumulative cardiotoxicity is a concern, as does study of its use with other potentially cardiotoxic agents.

Metnase mediates resistance to topoisomerase II inhibitors in breast cancer cells

DNA replication produces tangled, or catenated, chromatids, that must be decatenated prior to mitosis or catastrophic genomic damage will occur. Topoisomerase IIalpha (Topo IIalpha) is the primary decatenating enzyme. Cells monitor catenation status and activate decatenation checkpoints when decatenation is incomplete, which occurs when Topo IIalpha is inhibited by chemotherapy agents such as the anthracyclines and epididophyllotoxins. We recently demonstrated that the DNA repair component Metnase (also called SETMAR) enhances Topo IIalpha-mediated decatenation, and hypothesized that Metnase could mediate resistance to Topo IIalpha inhibitors. Here we show that Metnase interacts with Topo IIalpha in breast cancer cells, and that reducing Metnase expression significantly increases metaphase decatenation checkpoint arrest. Repression of Metnase sensitizes breast cancer cells to Topo IIalpha inhibitors, and directly blocks the inhibitory effect of the anthracycline adriamycin on Topo IIalpha-mediated decatenation in vitro. Thus, Metnase may mediate resistance to Topo IIalpha inhibitors, and could be a biomarker for clinical sensitivity to anthracyclines. Metnase could also become an important target for combination chemotherapy with current Topo IIalpha inhibitors, specifically in anthracycline-resistant breast cancer.

Mechanisms of induction of apoptosis by anthraquinone anticancer drugs aclarubicin and mitoxantrone in comparison with doxorubicin: relation to drug cytotoxicity and caspase-3 activation

We examined molecular events and morphological features associated with apoptosis induced by anthraquinone anticancer drugs aclarubicin, mitoxantrone and doxorubicin in two spontaneously immortalized cell lines (NIH 3T3 and B14) in relation to cytotoxicity of these drugs. The investigated cells showed similar sensitivity to aclarubicin but different sensitivity to doxorubicin and mitoxantrone: mitoxantrone was the most cytotoxic drug in both cell lines. All three drugs triggered both apoptosis and necrosis but none of these processes was positively correlated with their cytotoxicity. Apoptosis was the prevalent form of cell kill by aclarubicin, while doxorubicin and mitoxantrone induced mainly the necrotic mode of cell death. The extent and the timing of apoptosis were strongly dependent on the cell line, the type of the drug and its dose, and were mediated by caspase-3 activation. A significant increase in caspase-3 activity and the percentage of apoptotic cells, oligonucleosomal DNA fragmentation, chromatin condensation and formation of apoptotic bodies was observed predominantly in B14 cells. NIH 3T3 cells showed lesser changes and a lack of DNA fragmentation. Aclarubicin was the fastest acting drug, inducing DNA fragmentation 12 h earlier than doxorubicin, and 24 h earlier than mitoxantrone. Caspase-3 inhibitor Ac-DEVD-CHO did not show any significant effect on drug cytotoxicity and DNA nucleosomal fragmentation.

Gene expression profiles as biomarkers for the prediction of chemotherapy drug response in human tumour cells

Genome profiling approaches such as cDNA microarray analysis and quantitative reverse transcription polymerase chain reaction are playing ever-increasing roles in the classification of human cancers and in the discovery of biomarkers for the prediction of prognosis in cancer patients. Increasing research efforts are also being directed at identifying set of genes whose expression can be correlated with response to specific drugs or drug combinations. Such genes hold the prospect of tailoring chemotherapy regimens to the individual patient, based on tumour or host gene expression profiles. This review outlines recent advances and challenges in using genome profiling for the identification of tumour or host genes whose expression correlates with response to chemotherapy drugs both in vitro and in clinical studies. Genetic predictors of response to a variety of anticancer agents are discussed, including the anthracyclines, taxanes, topoisomerase I and II inhibitors, nucleoside analogs, alkylating agents, and vinca alkaloids.

Targeting liposomal chemotherapy via both tumor cell-specific and tumor vasculature-specific ligands potentiates therapeutic efficacy

Neuroblastoma, the most common solid tumor of infancy derived from the sympathetic nervous system, continues to present a formidable clinical challenge. Sterically stabilized immunoliposomes (SIL) have been shown to enhance the selective localization of entrapped drugs to solid tumors, with improvements in therapeutic indices. We showed that SIL loaded with doxorubicin (DXR) and targeted to the disialoganglioside receptor GD(2) [aGD(2)-SIL(DXR)] led to a selective inhibition of the metastatic growth of experimental models of human neuroblastoma. By coupling NGR peptides that target the angiogenic endothelial cell marker aminopeptidase N to the surface of DXR-loaded liposomes [NGR-SL(DXR)], we obtained tumor regression, pronounced destruction of the tumor vasculature, and prolonged survival of orthotopic neuroblastoma xenografts. Here, we showed good liposome stability, long circulation times, and enhanced time-dependent tumor accumulation of both the carrier and the drug. Antivascular effects against animal models of lung and ovarian cancer were shown for formulations of NGR-SL(DXR). In the chick embryo chorioallantoic assay, NGR-SL(DXR) substantially reduced the angiogenic potential of various neuroblastoma xenografts, with synergistic inhibition observed for the combination of NGR-SL(DXR) with aGD(2)-SIL(DXR). A significant improvement in antitumor effects was seen in neuroblastoma-bearing animal models when treated with the combined formulations compared with control mice or mice treated with either tumor- or vascular-targeted liposomal formulations, administered separately. The combined treatment resulted in a dramatic inhibition of tumor endothelial cell density. Long-term survivors were obtained only in animals treated with the combined tumor- and vascular-targeted formulations, confirming the pivotal role of combination therapies in treating aggressive metastatic neuroblastoma.

In vitro and in vivo reversal of MDR1-mediated multidrug resistance by KT-5720: Implications on hematological malignancies

Multidrug resistance (MDR) due to over-expression of the MDR1 (ABCB1) gene and its P-glycoprotein (Pgp) product is an obstacle in the treatment of hematological malignancies. In this study, we have evaluated the potency of KT-5720 to reverse Pgp-dependent MDR in vitro and in vivo. KT-5720 (but not its close derivatives, K252a and K252b) reversed multidrug resistance of LM1/MDR cell line at non-toxic concentrations and increased accumulation of rhodamine 123 (Rh123). KT-5720 significantly reversed MDR1-dependent resistance of primary malignant cells from patients with chronic myelogenous leukemia in blast crisis (CML-BC) and advanced multiple myeloma (MM). Moreover, KT-5720 (at 5 mg/kg) sensitized the bone marrow of MDR1 transgenic mice model towards daunorubicin (at 8 mg/kg) without general toxic effects. Therefore, KT-5720 can be considered as candidate for combination therapy in various hematological malignancies where Pgp activity is a major impediment for cure.

Proanthocyanidin from grape seeds potentiates anti-tumor activity of doxorubicin via immunomodulatory mechanism

The purpose of this study was to investigate the anti-tumor activities of proanthocyanidin (PA) from grape seeds and doxorubicin (DOX) in vitro as well as in vivo, either alone or in combination and to explore the immunomodulatory mechanism in tumor-bearing mice. PA (12.5 approximately 200 mg/l) or DOX (0.01 approximately 1 mg/l) for 24 h significantly inhibited YAC-1 cell proliferation (IC(50) 57.53 or 0.198 mg/l, respectively) in a concentration-dependent manner using microculture tetrazolium (MTT) assay. Meanwhile, a combination of PA (12.5, 25 mg/l) with DOX strongly inhibited cell proliferation with IC(50) values of DOX decreasing by 0.09 and 0.045 mg/l, respectively. In mouse tumor xenograft models, intraperitoneal administrations of PA (10 mg/kg) daily or DOX (2 mg/kg) every other day for 9 days significantly inhibited the growth of sarcoma 180, whereas a combination of the two strongly inhibited tumor growth as compared with PA or DOX alone (p<0.01). In contrast to PA treatment, DOX inhibited Con A-stimulated lymphocyte proliferation, IL-2 and IFN-gamma productions, NK cell cytotoxicity and CD4+/CD8+ ratio, while the administration of PA combined with DOX significantly enhanced the above immune responses as compared with the tumor-bearing control (p<0.01). Taken together, these results suggest that PA has anti-tumor activity and increases the anti-tumor activity of DOX, and the mechanism might be related partially to immunopotentiating activities through the enhancements of lymphocyte proliferation, NK cell cytotoxicity, CD4+/CD8+ ratio, IL-2 and IFN-gamma productions.

Combination radiofrequency ablation with intratumoral liposomal doxorubicin: effect on drug accumulation and coagulation in multiple tissues and tumor types in animals

PURPOSE

To determine whether use of radiofrequency (RF) ablation combined with intravenously (IV) administered liposomal doxorubicin, as compared with use of RF ablation or doxorubicin alone, facilitates increased tissue coagulation and interstitial drug accumulation in animal models.

MATERIALS AND METHODS

The institutional animal care and use committee approved this study. In experiment 1, multiple canine sarcomas were implanted in seven mildly immunosuppressed dogs and grown to a mean diameter of 4.8 cm. Tumors were assigned to three treatment groups: internally cooled RF ablation (12 minutes, 2000-mA pulsed technique) followed by IV liposomal doxorubicin (10 mg per animal) (n = 6), RF ablation alone (n = 6), and liposomal doxorubicin alone (n = 4). In experiment 2, the livers and kidneys of 10 rabbits and the thigh muscles of 10 rats were randomly assigned to one of two treatment groups: conventional RF ablation (90 degrees C +/- 2, 5 minutes) followed by IV liposomal doxorubicin (5 mg per rabbit, 1 mg per rat) or RF ablation alone (n = 5, each). Coagulation diameter and interstitial doxorubicin concentration (tissues were homogenized in acid alcohol, with doxorubicin extracted for 24 hours at 5 degrees C and quantified with fluorimetry) were measured 48 hours after treatment and compared. Multivariate analysis of variance and subsequent pairwise t tests (alpha = .05, two-tailed test) were performed.

RESULTS

Data are means +/- standard errors of the mean. A larger diameter of tumor destruction was observed in canine sarcomas treated with RF ablation-liposomal doxorubicin (3.7 cm +/- 0.6) compared with that in tumors treated with RF ablation (2.3 cm +/- 0.1) or liposomal doxorubicin (0.0 cm +/- 0.0) alone (P < .01). A new finding was a completely necrotic red zone (1.6 cm +/- 0.7) surrounding the central RF ablation-induced white coagulation zone. Greater but nonuniform drug uptake was observed particularly in this red zone (77.0 ng/g +/- 18.2) compared with uptake in the central zone (15.1 ng/g +/- 3.2), peripheral area of untreated tumor (38.9 ng/g +/- 8.0), and tumors treated with liposomal doxorubicin alone (43.9 ng/g +/- 6.7 for all regions) (P < .01 for all individual comparisons). In experiment 2, use of combined therapy led to increased coagulation in all tissues (liver: 17.6 mm +/- 3.1, P = .03; kidney: 11.0 mm +/- 3.1, P = .03; muscle: 13.1 mm +/- 1.3, P < .01) compared with use of RF ablation alone (liver, 13.4 mm +/- 1.5; kidney, 7.9 mm +/- 0.7; muscle, 8.6 mm +/- 0.5). Combined therapy, as compared with liposomal doxorubicin therapy alone, was also associated with increased doxorubicin accumulation in liver, kidney, and muscle (1.56 microg/g +/- 0.34, 4.36 microg/g +/- 1.78, and 3.63 microg/g +/- 1.43, respectively, vs 1.00 microg/g +/- 0.18, 1.23 microg/g +/- 0.32, and 0.87 microg/g +/- 0.53, respectively) (P < or = .01 for all individual comparisons).

CONCLUSION

Use of RF ablation combined with liposomal doxorubicin facilitates increased tissue coagulation and interstitial doxorubicin accumulation in multiple tissues and tumor types and may be useful for treatment of large tumors and achieving an ablative margin within the untreated tissue surrounding RF ablation-treated tumors.

Cell type-specific effects of asbestos on intracellular ROS levels, DNA oxidation and G1 cell cycle checkpoint

Exposure to asbestos fibers increases the risk of development of mesotheliomas and lung carcinomas, but not fibrosarcomas. We present data suggesting that resistance of fibroblasts to asbestos-induced carcinogenesis is likely to be connected with their lower ability to generate reactive oxygen species (ROS) in response to asbestos exposure and stricter control of proliferation of cells bearing asbestos/ROS-induced injuries. In fact, chrysotile (Mg6Si4O10(OH)8) asbestos exposure (5-10 microg/cm2) increased intracellular ROS and 8-oxo-guanine contents in rat pleural mesothelial cells, but not in lung fibroblasts. Simultaneously, moderate dosages of chrysotile and other agents increasing ROS levels (hydrogen peroxide, H2O2 and ethyl-methanesulfonate, EMS) inhibited cell cycle progression, in particular G1-to-S transition, in fibroblasts, but not in mesothelial cells. The arrested fibroblasts underwent cell death, while the majority of chrysotile-treated mesothelial cells survived. The differences in cell cycle response to asbestos/ROS-induced injuries correlated with distinct activity of p53-p21Cip1/Waf1 pathway in the two cell types. Chrysotile, H2O2 and EMS caused p53 upregulation in both cell types, but mesothelial cells, unlike fibroblasts, showed no accumulation of p21Cip1/Waf1. Of note, treatment with doxorubicin caused similar p53-dependent p21Cip1/Waf1 upregulation and cell cycle arrest in both cell types. This suggests differential response of fibroblasts and mesothelial cells specifically to asbestos/ROS exposure rather than to all DNA-damaging insults.

Cross-resistance studies of isogenic drug-resistant breast tumor cell lines support recent clinical evidence suggesting that sensitivity to paclitaxel may be strongly compromised by prior doxorubicin exposure

Less than half of breast cancer patients respond to second-line chemotherapy with paclitaxel after failing treatment with anthracyclines such as doxorubicin. A recent clinical trial by Paridaens et al. [J. Clin. Oncol. 18 : 724-733, 2000] examined whether patients may derive a better clinical benefit if paclitaxel was administered before doxorubicin. While overall survival was similar regardless of the order of drug administration, a >4-fold reduction in the response rate to paclitaxel was observed after late crossover from doxorubicin, compared to the response rate to doxorubicin after late crossover from paclitaxel. This may be related to differences in the ability of the drugs to induce cross-resistance to each other. To test this hypothesis, we examined whether isogenic breast tumor cells selected for resistance to doxorubicin exhibit greater cross-resistance to paclitaxel and other drugs than identical cells selected for resistance to paclitaxel. We found that cells selected for resistance to paclitaxel showed strong resistance (>/=40-fold) to paclitaxel and docetaxel, with little cross-resistance (4-fold) to doxorubicin. In contrast, cells selected for resistance to doxorubicin exhibited 50-fold resistance to doxorubicin and a dramatic 4700-fold and 14,600-fold cross-resistance to paclitaxel and docetaxel, respectively. Doxorubicin-resistant cells exhibited higher P-glycoprotein and breast cancer resistance protein (BCRP) levels than paclitaxel-resistant cells. In addition, procaspase-9 was strongly downregulated in doxorubicin-resistant cells but not in paclitaxel-resistant cells. These differences may account for the contrasting cross-resistance profiles observed for the two cell lines and may help to explain why treatment of breast cancer patients with paclitaxel appears to be compromized by prior doxorubicin exposure.

Structure and function of "metalloantibiotics"

Although most antibiotics do not need metal ions for their biological activities, there are a number of antibiotics that require metal ions to function properly, such as bleomycin (BLM), streptonigrin (SN), and bacitracin. The coordinated metal ions in these antibiotics play an important role in maintaining proper structure and/or function of these antibiotics. Removal of the metal ions from these antibiotics can cause changes in structure and/or function of these antibiotics. Similar to the case of "metalloproteins," these antibiotics are dubbed "metalloantibiotics" which are the title subjects of this review. Metalloantibiotics can interact with several different kinds of biomolecules, including DNA, RNA, proteins, receptors, and lipids, rendering their unique and specific bioactivities. In addition to the microbial-originated metalloantibiotics, many metalloantibiotic derivatives and metal complexes of synthetic ligands also show antibacterial, antiviral, and anti-neoplastic activities which are also briefly discussed to provide a broad sense of the term "metalloantibiotics."

Doxorubicin and two of its analogues are preferential inducers of homologous recombination compared with mutational events in somatic cells of Drosophila melanogaster

The genotoxic effects of the anthracycline doxorubicin (DOX) and two of its analogues, epirubicin (EPI) and pirarubicin (THP) were studied using the wing Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster. These compounds are classified as topoisomerase II (topo II) poisons, acting by stabilizing a topoisomerase II-cleaved DNA complex. Using the standard version of the SMART test it was possible to estimate the quantitative and qualitative genotoxic effects of these compounds, comparing the wing spot frequencies in marker- and balancer-heterozygous flies. The results obtained indicate that all three compounds induce a high frequency of spots related to homologous recombination (HR), which is the major event responsible for their genetic toxicity. Pirarubicin was the most genotoxic anthracycline, inducing approximately 21 times more genetic lesions than doxorubicin, probably due to the presence of a second sugar ring in the amino sugar moiety in its chemical structure. Although the only difference between epirubicin and doxorubicin is the steric position of the amino sugar 4'-OH in the molecule, epirubicin is approximately 1.6 times as genotoxic as doxorubicin.