FEC (5-fluorouracil, epidoxorubicin and cyclophosphamide) versus EM (epidoxorubicin and mitomycin-C) with or without lonidamine as first-line treatment for advanced breast cancer. A multicentric randomised study. Final results

NEAT1 repression by MED12 creates chemosensitivity in p53 wild-type breast cancer cells

Breast cancer is often treated with chemotherapy. However, the development of chemoresistance results in treatment failure. Long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) has been shown to contribute to chemoresistance in breast cancer cells. In studying the transcriptional regulation of NEAT1 using multi-omics approaches, we showed that NEAT1 is up-regulated by 5-fluorouracil in breast cancer cells with wild-type cellular tumor antigen p53 but not in mutant-p53-expressing breast cancer cells. The regulation of NEAT1 involves mediator complex subunit 12 (MED12)-mediated repression of histone acetylation marks at the promoter region of NEAT1. Knockdown of MED12 but not coactivator-associated arginine methyltransferase 1 (CARM1) induced histone acetylation at the NEAT1 promoter, leading to elevated NEAT1 mRNAs, resulting in a chemoresistant phenotype. The MED12-dependent regulation of NEAT1 differs between wild-type and mutant p53-expressing cells. MED12 depletion led to increased expression of NEAT1 in a wild-type p53 cell line, but decreased expression in a mutant p53 cell line. Chemoresistance caused by MED12 depletion can be partially rescued by NEAT1 knockdown in p53 wild-type cells. Collectively, our study reveals a novel mechanism of chemoresistance dependent on MED12 transcriptional regulation of NEAT1 in p53 wild-type breast cancer cells.

Is antitumor Pt(IV) complex containing two axial lonidamine ligands a true dual- or multi-action prodrug?

This work studied the mechanism of action of a Pt(IV) complex 2 bearing two axial lonidamine ligands, which are selective inhibitors of aerobic glycolysis. The presence of two lonidamine ligands in 2 compared to the parent Pt(II) complex increased its antiproliferative activity, cellular accumulation, and changed its cell cycle profile and mechanism of cell death. In 3D cell culture, 2 showed exceptional antiproliferative activity with IC50 values as low as 1.6 μM in MCF7 cells. The study on the influence of the lonidamine ligands in the Pt complex on glycolysis showed only low potency of ligands to affect metabolic processes in cancer cells, making the investigated complex, not a dual- or multi-action prodrug. However, the Pt(IV) prodrug effectively delivers the cytotoxic Pt(II) complex into cancer cells.

Metabolic Reprogramming of Colorectal Cancer Cells and the Microenvironment: Implication for Therapy

Colorectal carcinoma (CRC) is one of the most frequently diagnosed carcinomas and one of the leading causes of cancer-related death worldwide. Metabolic reprogramming, a hallmark of cancer, is closely related to the initiation and progression of carcinomas, including CRC. Accumulating evidence shows that activation of oncogenic pathways and loss of tumor suppressor genes regulate the metabolic reprogramming that is mainly involved in glycolysis, glutaminolysis, one-carbon metabolism and lipid metabolism. The abnormal metabolic program provides tumor cells with abundant energy, nutrients and redox requirements to support their malignant growth and metastasis, which is accompanied by impaired metabolic flexibility in the tumor microenvironment (TME) and dysbiosis of the gut microbiota. The metabolic crosstalk between the tumor cells, the components of the TME and the intestinal microbiota further facilitates CRC cell proliferation, invasion and metastasis and leads to therapy resistance. Hence, to target the dysregulated tumor metabolism, the TME and the gut microbiota, novel preventive and therapeutic applications are required. In this review, the dysregulation of metabolic programs, molecular pathways, the TME and the intestinal microbiota in CRC is addressed. Possible therapeutic strategies, including metabolic inhibition and immune therapy in CRC, as well as modulation of the aberrant intestinal microbiota, are discussed.

S1PR3-G12-biased agonist ALESIA targets cancer metabolism and promotes glucose starvation

Metabolic activities are altered in cancer cells compared with those in normal cells, and the cancer-specific pathway becomes a potential therapeutic target. Higher cellular glucose consumption, which leads to lower glucose levels, is a hallmark of cancer cells. In an objective screening for chemicals that induce cell death under low-glucose conditions, we discovered a compound, denoted as ALESIA (Anticancer Ligand Enhancing Starvation-induced Apoptosis). By our shedding assay of transforming growth factor α in HEK293A cells, ALESIA was determined to act as a sphingosine-1-phosphate receptor 3-G₁₂-biased agonist that promotes nitric oxide production and oxidative stress. The oxidative stress triggered by ALESIA resulted in the exhaustion of glucose, cellular NADPH deficiency, and then cancer cell death. Intraperitoneal administration of ALESIA improved the survival of mice with peritoneally disseminated rhabdomyosarcoma, indicating its potential as a new type of anticancer drug for glucose starvation therapy.

The Potential of Lonidamine in Combination with Chemotherapy and Physical Therapy in Cancer Treatment

Simple Summary

The unique characteristics of tumor energy metabolism (highly dependent on aerobic glycolysis, namely, the Warburg effect) make it an interesting and attractive target for drug discovery. Radio- and chemoresistance are closely associated with the Warburg effect. Lonidamine (LND), as a glycolytic inhibitor, although having low anticancer activity when used alone, exhibits selectivity to various tumors, and its adverse effects do not overlap when combined with other chemotherapeutic drugs. Therefore, LND may be very promising as a sensitizer of tumors to chemotherapeutic agents and physical therapies. This review summarizes the advance of LND in combination with chemotherapy and physical therapy over the past several decades, as well as the promising LND derivative adjudin (ADD). The underlying sensitizing mechanisms were also analyzed and discussed, which may contribute to an improved therapeutic effect in future clinical cancer treatment.

Abstract

Lonidamine (LND) has the ability to resist spermatogenesis and was first used as an anti-spermatogenic agent. Later, it was found that LND has a degree of anticancer activity. Currently, LND is known to target energy metabolism, mainly involving the inhibition of monocarboxylate transporter (MCT), mitochondrial pyruvate carrier (MPC), respiratory chain complex I/II, mitochondrial permeability transition (PT) pore, and hexokinase II (HK-II). However, phase II clinical studies showed that LND alone had a weak therapeutic effect, and the effect was short and reversible. Interestingly, LND does not have the common side effects of traditional chemotherapeutic drugs, such as alopecia and myelosuppression. In addition, LND has selective activity toward various tumors, and its toxic and side effects do not overlap when combined with other chemotherapeutic drugs. Therefore, LND is commonly used as a chemosensitizer to enhance the antitumor effects of chemotherapeutic drugs based on its disruption of energy metabolism relating to chemo- or radioresistance. In this review, we summarized the combination treatments of LND with several typical chemotherapeutic drugs and several common physical therapies, such as radiotherapy (RT), hyperthermia (HT), and photodynamic therapy (PDT), and discussed the underlying mechanisms of action. Meanwhile, the development of novel formulations of LND in recent years and the research progress of LND derivative adjudin (ADD) as an anticancer drug were also discussed.

Mechanism of antineoplastic activity of lonidamine

Lonidamine (LND) was initially introduced as an antispermatogenic agent. It was later found to have anticancer activity sensitizing tumors to chemo-, radio-, and photodynamic-therapy and hyperthermia. Although the mechanism of action remained unclear, LND treatment has been known to target metabolic pathways in cancer cells. It has been reported to alter the bioenergetics of tumor cells by inhibiting glycolysis and mitochondrial respiration, while indirect evidence suggested that it also inhibited l-lactic acid efflux from cells mediated by members of the proton-linked monocarboxylate transporter (MCT) family and also pyruvate uptake into the mitochondria by the mitochondrial pyruvate carrier (MPC). Recent studies have demonstrated that LND potently inhibits MPC activity in isolated rat liver mitochondria (K_i 2.5μM) and cooperatively inhibits l-lactate transport by MCT1, MCT2 and MCT4 expressed in Xenopus laevis oocytes with K_0.5 and Hill coefficient values of 36-40μM and 1.65-1.85, respectively. In rat heart mitochondria LND inhibited the MPC with similar potency and uncoupled oxidation of pyruvate was inhibited more effectively (IC₅₀~7μM) than other substrates including glutamate (IC₅₀~20μM). LND inhibits the succinate-ubiquinone reductase activity of respiratory Complex II without fully blocking succinate dehydrogenase activity. LND also induces cellular reactive oxygen species through Complex II and has been reported to promote cell death by suppression of the pentose phosphate pathway, which resulted in inhibition of NADPH and glutathione generation. We conclude that MPC inhibition is the most sensitive anti-tumour target for LND, with additional inhibitory effects on MCT-mediated l-lactic acid efflux, Complex II and glutamine/glutamate oxidation.

Survival of patients with de-novo metastatic breast cancer: analysis of data from a large breast cancer-specific private practice, a university-based cancer center and review of the literature

Approximately 6 % of patients with breast cancer are diagnosed with de-novo distant metastases. We set out to look at two cohorts of patients seen at breast cancer-specific practices, compare the results to other reports and larger databases, and see how advances in treatment have impacted overall survival (OS). The records from a large breast cancer oncology private practice and a second data set from the University of Miami/Sylvester Comprehensive Cancer Center (UM/SCCC) tumor database were, retrospectively, reviewed to identify patients with de-novo metastases. We included those patients identified to have metastatic disease within 3 months of diagnosis of a breast primary cancer. Patients diagnosed between 1996 and 2006 were chosen for our study population. The OS for the private practice was 41.0 months (46.0 for ER positive and 26.0 for ER negative) and 36.0 months for UM/SCCC (52 months for ER positive and 36 months for ER negative). ER negativity and CNS- or visceral-dominant disease were associated with a significantly worse prognosis within the private practice. Dominant site was associated with a significantly worse prognosis within the UM/SCCC database but with a trend also for ER negativity. Age and ethnicity did not contribute significantly to the survival of patients within either cohort. The median survival in both cohorts and most other reported series was larger than that seen in the surveillance, epidemiology, and end results program and the National Cancer Database. The median OS among patients with de-novo metastatic breast cancer treated within two breast-specific oncology practices was over 3 years, which appears better than larger, more inclusive databases and publications from earlier decades.

Reviving Lonidamine and 6-Diazo-5-oxo-L-norleucine to Be Used in Combination for Metabolic Cancer Therapy

Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural targets for cancer therapy. Currently, a number of newer compounds to block glycolysis and glutaminolysis are being developed; nevertheless, lonidamine and 6-diazo-5-oxo-L-norleucine (DON) are two old drugs well characterized as inhibitors of glycolysis and glutaminolysis, respectively, whose clinical development was abandoned years ago when the importance of cancer metabolism was not fully appreciated and clinical trial methodology was less developed. In this review, a PubMed search using the words lonidamine and 6-diazo-5-oxo-L-norleucine (DON) was undertaken to analyse existing information on the preclinical and clinical studies of these drugs for cancer treatment. Data show that they exhibit antitumor effects; besides there is also the suggestion that they are synergistic. We conclude that lonidamine and DON are safe and potentially effective drugs that need to be reevaluated in combination as metabolic therapy of cancer.

Investigational cancer drugs targeting cell metabolism in clinical development

Introduction: Malignant cell transformation and tumor progression are associated with alterations in glycolysis, fatty acid synthesis, amino acid delivery and production of reactive oxygen species. With increased understanding of the role of metabolism in tumors, there has been interest in developing agents that target tumor specific metabolic pathways. Numerous promising agents targeting altered metabolic pathways are currently in Phase I - III clinical trials. Areas covered: This paper reviews the early phase clinical trial development of these agents and provides perspective on the future direction of this emerging field. Specifically, the authors describe novel and repurposed therapies, focusing on the effects of each agent on tumor metabolism and results from relevant Phase I and II clinical trials. Expert opinion: Metabolism modulating agents, alone and in combinations with other classes of agents, have shown efficacy in the treatment of neoplasm, which, the authors believe, will bear positive results in future studies. Because of the significant crosstalk between metabolic pathways and oncogenic signaling pathways, the authors also believe that combining metabolic modifiers with targeted agents will be an important strategy. An increased understanding of cancer metabolism, in addition to the continued study of metabolic modulators, should lead to further advances in this nascent therapeutic field in the future.

Synergistic nanoparticulate drug combination overcomes multidrug resistance, increases efficacy, and reduces cardiotoxicity in a nonimmunocompromised breast tumor model

Anthracyclines, commonly employed for cancer chemotherapy, suffer from dose-limiting cardiotoxicity and poor efficacy due to multidrug resistance (MDR). We previously demonstrated that simultaneous delivery of the synergistic drugs doxorubicin (DOX) and mitomycin C (MMC) by polymer-lipid hybrid nanoparticles (PLN) circumvented MDR, increased efficacy, and reduced cardiotoxicity in immuncompromised mice superior to poly(ethylene glycol)-coated (PEGylated) lipososmal DOX (PLD). Herein it is shown that the DOX-MMC combination was also synergistic in MDR EMT6/AR1 murine breast cancer cells and that their nanoparticle formulations were able to overcome the MDR phenotype. In contrast PLD exhibited little or no effect on the MDR cells. For the first time, these differences in in vitro efficacy are shown to be strongly correlated with cellular uptake and intracellular distribution of DOX brought about by DOX formulations (e.g., free solution, PLN vs PLD). To take into consideration the role of an intact immune system and tumor stroma in the response of host and tumor to chemotherapy, use was made of nonimmunocomprised mouse models to study the dose tolerance, cardiotoxicity, and efficacy of DOX-MMC coloaded PLN (DMsPLN) compared to PLD. DMsPLN treatment at 50 mg/m(2) DOX and 17 mg/m(2) of MMC singly or once every 4 days for 4 cycles were well tolerated by the mice without elevated systemic toxicity blood markers or myocardial damage. In contrast, PLD was limited to a single treatment due to significant total weight loss. The DMsPLN treatment delayed tumor growth up to 312% and 28% in EMT6/WT and EMT6/AR1 models, respectively. This work supports the translational value of DMsPLN for the aggressive management of either naïve or anthracycline-resistant tumors.

Pneumocystis pneumonia during Postoperative Adjuvant Chemotherapy for Breast Cancer

A 72-year-old woman underwent a mastectomy with one-stage breast reconstruction using silicone implant for right breast cancer. Postoperatively, she had received adjuvant chemotherapy with fluorouracil, epirubicin, and cyclophosphamide (FEC regimen). She was admitted for febrile neutropenia after the third course of chemotherapy. She remained febrile for a week, and she complained of dyspnea on hospital day 8. Computed tomography scan demonstrated widespread patchy ground glass changes in both lungs and serum (1→3)-β-D-glucan was elevated to 20 pg/mL. Oral trimethoprim-sulfamethoxazole was started on the strong clinical suspicion of PCP, and the patient subsequently made a rapid recovery from fever and dyspnea.

Targeting glucose metabolism: an emerging concept for anticancer therapy

Mortality from locally advanced and metastatic cancer remains high despite advances in our understanding of the molecular basis of the disease and improved adjuvant therapies. Recently, there has been an increased interest in cancer metabolomics, and in particular, the potential for targeting glucose metabolism, for therapeutic gain. This interest stems from the fact that cancer cells metabolize glucose very differently from normal cells. Cancer cells preferentially switch to aerobic glycolysis rather than oxidative phosphorylation as their means of glucose metabolism. This metabolic switch is believed to enhance cancer cell survival. Several therapeutic agents that target tumor metabolism have shown significant cancer cell cytotoxicity in preclinical studies, and some have progressed to clinical trials. In this review, we discuss the alteration of carbohydrate metabolism seen in cancer cells, the underlying mechanisms, and opportunities for targeting cancer metabolism for therapeutic purposes.

Assessment of quality of life in advanced breast cancer. An overview of randomized phase III trials

BACKGROUND

Health-related quality of life (HRQOL) parameters are often used as end points in phase III trials in advanced breast cancer. The frequency and correlates of significant gains in HRQOL have not been assessed.

METHODS

To evaluate the contemporary role for HRQOL assessment in advanced breast cancer, we searched PubMed for the main and companion papers reporting the results of phase III trials on systemic antineoplastic therapies published between 1/98 and 7/09 in 11 leading journals.

RESULTS

The search yielded 87 trials that enrolled a total of 33,669 patients. HRQOL was mentioned/reported in the main paper in 34 trials, reported in a companion paper in one (a total of 35/87=40%), and mentioned in the abstract of the main paper in 19/34 cases (56%). There was no temporal trend for reporting on HRQOL in the two 6-year periods. Although formal statistical comparisons were reported in 31/35 cases (89%), a significant difference was found in only 4/31 (13%) trials, always favoring the experimental arm. Given the small number of studies with a significant HRQOL finding, we could not assess correlates of gain in HRQOL.

CONCLUSIONS

HRQOL is one of the key indicators of treatment benefit in advanced breast cancer, but contemporary systemic therapies in this setting do not appear to affect HRQOL differentially.

Overall survival and post-progression survival in advanced breast cancer: a review of recent randomized clinical trials

With the availability of several lines of therapy, overall survival (OS) has been progressively substituted by progression-free survival (PFS) and other tumor-based assessments as the primary efficacy end point in advanced breast cancer trials. We investigated the frequency and determinants of OS gain in the recent literature and the duration of post-progression survival (PPS) according to treatment type and line. We used PubMed to search for phase III trials on systemic antineoplastic therapies published between January 1998 and December 2007 in 11 leading journals. The primary end point was the one stated explicitly, used for N calculation, or listed first. Significant gain was considered as reported P < .05 for superiority trials or proven non-inferiority or equivalence otherwise. We retrieved 76 trials, and gain in OS was reported in 15 cases (19.7%). The median gain in OS was 4.7 months, and such gain was more frequent when there was significant gain in PFS and in second-line and third-line trials. The average median OS was 20.7 months in trials assessing first-line chemotherapy and 31.1 months with first-line hormone therapy. The median proportion of OS accounted for by PPS was significantly longer in hormone therapy trials than in chemotherapy trials, but varied little across treatment lines. A statistically significant gain in OS has been reported in about one in five recent phase III trials in advanced breast cancer, despite the fact that OS has seldom been used as the primary end point. PPS represents nearly two thirds of patient survival after on-trial disease progression.

Improving outcome of chemotherapy of metastatic breast cancer by docosahexaenoic acid: a phase II trial

BACKGROUND

Breast cancer becomes lethal when visceral metastases develop. At this stage, anti-cancer treatments aim at relieving symptoms and delaying death without resulting in additional toxicity. On the basis of their differential anti-oxidant defence level, tumour cells can be made more sensitive to chemotherapy than non-tumour cells when membrane lipids are enriched with docosahexaenoic acid (DHA), a peroxidisable and oxidative-stress-inducing lipid of marine origin.

METHODS

This open-label single-arm phase II study evaluated the safety and efficacy (response rate), as primary end points, of the addition of 1.8 g DHA daily to an anthracycline-based chemotherapy (FEC) regimen in breast cancer patients (n = 25) with rapidly progressing visceral metastases. The secondary end points were time to progression (TTP) and overall survival (OS).

RESULTS

The objective response rate was 44%. With a mean follow-up time of 31 months (range 2-96 months), the median TTP was 6 months. Median OS was 22 months and reached 34 months in the sub-population of patients (n = 12) with the highest plasma DHA incorporation. The most common grade 3 or 4 toxicity was neutropaenia (80%).

CONCLUSION

DHA during chemotherapy was devoid of adverse side effects and can improve the outcome of chemotherapy when highly incorporated. DHA has a potential to specifically chemosensitise tumours.

A novel doxorubicin-mitomycin C co-encapsulated nanoparticle formulation exhibits anti-cancer synergy in multidrug resistant human breast cancer cells

Anthracycline-containing treatment regimens are currently the most widely employed regimens for the management of breast cancer. These drug combinations are often designed based on non-cross resistance and minimal overlapping toxicity rather than drug synergism. Moreover, aggressive doses are normally used in chemotherapy to achieve a greater therapeutic benefit at the cost of more acute and long-term toxic effects. To increase chemotherapeutic efficacy while decreasing toxic effects, rational design of drug synergy-based regimens is needed. Our previous work showed a synergistic effect of doxorubicin (DOX) and mitomycin C (MMC) on murine breast cancer cells in vitro and improved efficacy and reduced systemic toxicity of DOX-loaded solid polymer-lipid hybrid nanoparticles (PLN) in animal models of breast cancer. Herein we have demonstrated true anticancer synergy of concurrently applied DOX and MMC, and have rationally designed PLN to effectively deliver this combination to multidrug resistant (MDR) MDA435/LCC6 human breast cancer cells. DOX-MMC co-loaded PLN were effective in killing MDR cells at 20-30-fold lower doses than the free drugs. This synergistic cell killing was correlated with enhanced induction of DNA double strand breaks that preceded apoptosis. Importantly, co-encapsulation of dual agents into a nanoparticle formulation was much more effective than concurrent application of single agent-containing PLN, demonstrating the requirement of simultaneous uptake of both drugs by the same cells to enhance the drug synergy. The rationally designed combination chemotherapeutic PLN can overcome multidrug resistance at a significantly lower dose than free drugs, exhibiting the potential to enhance chemotherapy and reduce the therapeutic limitations imposed by systemic toxicity.

Progression-free survival and time to progression as primary end points in advanced breast cancer: often used, sometimes loosely defined

BACKGROUND

The growing availability of active agents makes the development of novel therapies increasingly complex and the choice of end points critical. We assessed the frequency of use of efficacy end points in advanced breast cancer.

METHODS

We searched PubMed for randomized trials published between 2000 and 2007 in 10 leading medical journals. We abstracted data on progression-free survival (PFS), time to tumor progression (TTP), response rate (RR) and overall survival.

RESULTS

A total of 58 studies enrolled 23,371 assessable patients in 122 treatment arms. The primary end points most frequently used were RR and TTP (n=21 each), followed by PFS (n=14). In five of the trials using TTP as the primary end point, no definition of TTP was reported; in 13 of the other 16 cases, death was counted as an event, making TTP indistinguishable from PFS. Trials having PFS, TTP or time to treatment failure as the primary end point (n=36) had a higher mean number of patients than those using RR (P=0.061).

CONCLUSION

Investigators seem to be frequently using PFS and TTP interchangeably in advanced breast cancer. Such use of terms may lead to confusion when results of different trials are compared, and uniform use of definitions seems in order.

Surrogate markers and survival in women receiving first-line combination anthracycline chemotherapy for advanced breast cancer

Surrogate markers may help predict the effects of first-line treatment on survival. This metaregression analysis examines the relationship between several surrogate markers and survival in women with advanced breast cancer after receiving first-line combination anthracycline chemotherapy 5-fluorouracil, adriamycin and cyclophosphamide (FAC) or 5-fluorouracil, epirubicin and cyclophosphamide (FEC) . From a systematic literature review, we identified 42 randomised trials. The surrogate markers were complete or partial tumour response, progressive disease and time to progression. The treatment effect on survival was quantified by the hazard ratio. The treatment effect on each surrogate marker was quantified by the odds ratio (or ratio of median time to progression). The relationship between survival and each surrogate marker was assessed by a weighted linear regression of the hazard ratio against the odds ratio. There was a significant linear association between survival and complete or partial tumour response (P<0.001, R²=34%), complete tumour response (P=0.02, R²=12%), progressive disease (P<0.001, R²=38%) and time to progression (P<0.0001, R²=56%); R² is the proportion of the variability in the treatment effect on survival that is explained by the treatment effect on the surrogate marker. Time to progression may be a useful surrogate marker for predicting survival in women receiving first-line anthracycline chemotherapy and could be used to estimate the survival benefit in future trials of first-line chemotherapy compared to FAC or FEC. The other markers, tumour response and progressive disease, were less good.

Long-term medical costs of postmenopausal breast cancer therapy

BACKGROUND

Since the incidence of breast cancer is growing, prevention programs can be expected to have a large economic impact on the health care system. From a health economic point of view, one is interested in the costs saved by disease prevention.

PATIENTS AND METHODS

To predict 10-year cumulative incidence-based costs of postmenopausal breast cancer, a state transitional model was developed based on published clinical data. The model simulates disease progression and includes nine health states of 1 year: node-negative and node-positive early cancer; local relapse; metastasis, each with its follow-up states; and death. The cost per state was obtained from a chart review in 118 patients with different disease states. Costs were calculated from the health insurance perspective and discounted at 3%.

RESULTS

The cumulative 10 year cost per patient was equal to 31,774 euro [95% confidence interval (CI) 30,536-33,012 euro] of which 30% was hospital costs, 28% systemic treatment, surgery and radiotherapy and 14% testing. Costs were at their highest following diagnosis and before death.

CONCLUSIONS

This incidence-based approach identified the cost of postmenopausal breast cancer over time and may serve as a valid baseline for assessment of new interventions in prevention or early treatment.

Mitochondria as a target for inducing death of malignant hematopoietic cells

Mitochondria plays a central role in apoptotic cell death. The intermembrane space of mitochondria contains a number of soluble molecules whose release from the organelle to the cytosol or the nucleus induces cell death. Thus, molecules that directly trigger mitochondria membrane permeabilisation are efficient cytotoxic drugs. Mitochondria is one of the cellular targets for commonly used epipodophyllotoxins, adenine deoxynucleoside analogs and taxanes as well as recently developped agents such as the pentacyclic triterpene betulinic acid and the lymphotoxic agent FTY720. Most informations on anthracyclines point to the mitochondrial membrane as the main target of cardiotoxicity. Mitochondria is also a target for arsenite trioxide, an old cytotoxic agent recently used for treating acute promyelocytic leukemia, lonidamine, a dichlorinated derivative of indazole-3-carboxylic acid developped as a chemosensitizer, the retinoic acid receptor gamma activator CD437 and nitric oxide (NO). Recently, cytotoxic drugs have been specifically designed to directly affect the mitochondrial function. These include the positively charged alpha-helical peptides, which are attracted to and disrupt the negatively charged mitochondrial membrane, thus inducing mammalian cell apoptosis when targeted intracellularly. Various strategies have been proposed also to directly inhibit Bcl-2 and related anti-apoptotic proteins, including antisense oligonucleotides (e.g. Genasense, currently tested in phase III trials), small molecules that mimic the BH3 dimerization domain of these proteins and kinase inhibitors. Ligands of the mitochondrial benzodiazepine receptor such as the isoquinolone carboxamide derivative PK11195 also overcome the membrane-stabilizing effect of Bcl-2, whereas the adenosine nucleotide translocator (ANT) and the mitochondrial DNA are two other potential cellular targets for cytotoxic agents. Potentially, new compounds directly targeting the mitochondria may be useful in treating hematological malignancies. The challenge is now to selectively target these mitochondria permeabilizing agents to malignant cells. This review briefly summarizes the role of the mitochondria in cell death and describes these various strategies for targeting the mitochondria to induce apoptosis.

Epirubicin: a review of its efficacy as adjuvant therapy and in the treatment of metastatic disease in breast cancer

Epirubicin is a semisynthetic derivative of doxorubicin which has been extensively evaluated in patients with breast cancer. It is effective in the management of metastatic disease and as adjuvant therapy in patients with early breast cancer. In the adjuvant setting, epirubicin-based therapy appears to have efficacy at least equivalent to that of the standard therapy cyclophosphamide, methotrexate and fluorouracil (CMF), with the most recent trials, predominantly in premenopausal patients, reporting significant gains in relapse-free survival and overall survival for epirubicin-based vs CMF therapy. In a single trial, the 5-year relapse-free survival of postmenopausal patients receiving long term hormonal therapy (tamoxifen) was significantly increased when epirubicin was added as single-agent chemotherapy and compared with tamoxifen alone. In patients with metastatic disease, epirubicin- and doxorubicin-containing regimens (with cyclophosphamide and fluorouracil; FEC and FAC) are therapeutically equivalent. Increasing the dose of epirubicin appears to improve response rates in patients with either metastatic or early disease but, with the exception of 1 adjuvant study, improved overall survival has not been demonstrated. Quality of life (QOL) has yet to be adequately evaluated with epirubicin. The major adverse effects of epirubicin are acute dose-limiting haematotoxicity and cumulative dose-related cardiotoxicity. Other important adverse effects include mucositis, nausea and vomiting, reversible alopecia and local cutaneous reactions. However, the tolerability of epirubicin is better than that of doxorubicin at equimolar doses.

CONCLUSION

Epirubicin has been extensively investigated in patients with breast cancer and has been found to be a highly effective agent, both for the treatment of patients with metastatic disease and as an adjuvant therapy. Recent trials have confirmed that, in selected patients requiring adjuvant therapy, FEC therapy is at least as effective as CMF, a standard treatment. FEC is also therapeutically equivalent to FAC in patients with metastatic breast cancer, and because the therapeutic index appears to be better the opportunity exists to increase dose intensity in an effort to improve efficacy. Such trials, and those of combinations of epirubicin with newer or alternative agents, should result in the introduction of more effective and better tolerated epirubicin-based protocols for adjuvant therapy and the management of patients with advanced breast cancer. In the meantime there is sufficient evidence to justify consideration of epirubicin for inclusion in first-line therapies for patients with early or metastatic breast cancer.