Linda T. Vahdat

Epithelial-to-mesenchymal transition is not required for lung metastasis but contributes to chemoresistance.

The role of epithelial-to-mesenchymal transition (EMT) in metastasis is a longstanding source of debate, largely owing to an inability to monitor transient and reversible EMT phenotypes in vivo. Here we establish an EMT lineage-tracing system to monitor this process in mice, using a mesenchymal-specific Cre-mediated fluorescent marker switch system in spontaneous breast-to-lung metastasis models. We show that within a predominantly epithelial primary tumour, a small proportion of tumour cells undergo EMT. Notably, lung metastases mainly consist of non-EMT tumour cells that maintain their epithelial phenotype. Inhibiting EMT by overexpressing the microRNA miR-200 does not affect lung metastasis development. However, EMT cells significantly contribute to recurrent lung metastasis formation after chemotherapy. These cells survived cyclophosphamide treatment owing to reduced proliferation, apoptotic tolerance and increased expression of chemoresistance-related genes. Overexpression of miR-200 abrogated this resistance. This study suggests the potential of an EMT-targeting strategy, in conjunction with conventional chemotherapies, for breast cancer treatment.The role of epithelial to mesenchymal transition (EMT) in metastasis is a longstanding source of controversy, largely due to an inability to monitor transient and reversible EMT phenotypes in vivo. We established an EMT lineage tracing system to monitor this process, using a mesenchymal-specific Cre-mediated fluorescent marker switch system in spontaneous breast-to-lung metastasis models. We confirmed that within a predominantly epithelial primary tumor, a small portion of tumor cells undergo EMT. Strikingly, lung metastases mainly consisted of non-EMT tumor cells maintaining their epithelial phenotype. Inhibiting EMT by overexpressing miR-200 did not impact lung metastasis development. However, EMT cells significantly contribute to recurrent lung metastasis formation after chemotherapy. These cells survived cyclophosphamide treatment due to reduced proliferation, apoptotic tolerance, and elevated expression of chemoresistance-related genes. Overexpression of miR-200 abrogated this resistance. This study suggests the potential of an EMT-targeting strategy, in conjunction with conventional chemotherapies, for breast cancer treatment.

Eribulin monotherapy versus treatment of physician's choice in patients with metastatic breast cancer (EMBRACE): a phase 3 open-label randomised study

BACKGROUND Treatments with survival benefit are greatly needed for women with heavily pretreated metastatic breast cancer. Eribulin mesilate is a non-taxane microtubule dynamics inhibitor with a novel mode of action. We aimed to compare overall survival of heavily pretreated patients receiving eribulin versus currently available treatments. METHODS In this phase 3 open-label study, women with locally recurrent or metastatic breast cancer were randomly allocated (2:1) to eribulin mesilate (1·4 mg/m(2) administered intravenously during 2-5 min on days 1 and 8 of a 21-day cycle) or treatment of physicians choice (TPC). Patients had received between two and five previous chemotherapy regimens (two or more for advanced disease), including an anthracycline and a taxane, unless contraindicated. Randomisation was stratified by geographical region, previous capecitabine treatment, and human epidermal growth factor receptor 2 status. Patients and investigators were not masked to treatment allocation. The primary endpoint was overall survival in the intention-to-treat population. This study is registered at ClinicalTrials.gov, number NCT00388726. FINDINGS 762 women were randomly allocated to treatment groups (508 eribulin, 254 TPC). Overall survival was significantly improved in women assigned to eribulin (median 13·1 months, 95% CI 11·8-14·3) compared with TPC (10·6 months, 9·3-12·5; hazard ratio 0·81, 95% CI 0·66-0·99; p=0·041). The most common adverse events in both groups were asthenia or fatigue (270 [54%] of 503 patients on eribulin and 98 [40%] of 247 patients on TPC at all grades) and neutropenia (260 [52%] patients receiving eribulin and 73 [30%] of those on TPC at all grades). Peripheral neuropathy was the most common adverse event leading to discontinuation from eribulin, occurring in 24 (5%) of 503 patients. INTERPRETATION Eribulin showed a significant and clinically meaningful improvement in overall survival compared with TPC in women with heavily pretreated metastatic breast cancer. This finding challenges the notion that improved overall survival is an unrealistic expectation during evaluation of new anticancer therapies in the refractory setting. FUNDING Eisai.

Ixabepilone Plus Capecitabine for Metastatic Breast Cancer Progressing After Anthracycline and Taxane Treatment

PURPOSE Effective treatment options for patients with metastatic breast cancer resistant to anthracyclines and taxanes are limited. Ixabepilone has single-agent activity in these patients and has demonstrated synergy with capecitabine in this setting. This study was designed to compare ixabepilone plus capecitabine versus capecitabine alone in anthracycline-pretreated or -resistant and taxane-resistant locally advanced or metastatic breast cancer. PATIENTS AND METHODS Seven hundred fifty-two patients were randomly assigned to ixabepilone 40 mg/m(2) intravenously on day 1 of a 21-day cycle plus capecitabine 2,000 mg/m(2) orally on days 1 through 14 of a 21-day cycle, or capecitabine alone 2,500 mg/m(2) on the same schedule, in this international phase III study. The primary end point was progression-free survival evaluated by blinded independent review. RESULTS Ixabepilone plus capecitabine prolonged progression-free survival relative to capecitabine (median, 5.8 v 4.2 months), with a 25% reduction in the estimated risk of disease progression (hazard ratio, 0.75; 95% CI, 0.64 to 0.88; P = .0003). Objective response rate was also increased (35% v 14%; P < .0001). Grade 3/4 treatment-related sensory neuropathy (21% v 0%), fatigue (9% v 3%), and neutropenia (68% v 11%) were more frequent with combination therapy, as was the rate of death as a result of toxicity (3% v 1%, with patients with liver dysfunction [>/= grade 2 liver function tests] at greater risk). Capecitabine-related toxicities were similar for both treatment groups. CONCLUSION Ixabepilone plus capecitabine demonstrates superior efficacy to capecitabine alone in patients with metastatic breast cancer pretreated or resistant to anthracyclines and resistant to taxanes.

Efficacy and Safety of Ixabepilone (BMS-247550) in a Phase II Study of Patients With Advanced Breast Cancer Resistant to an Anthracycline, a Taxane, and Capecitabine

PURPOSE To evaluate the efficacy and safety of ixabepilone in patients with metastatic breast cancer (MBC) resistant to anthracycline, taxane, and capecitabine, in this multicenter, phase II study. PATIENTS AND METHODS Patients with measurable disease who had tumor progression while receiving prior anthracycline, taxane, and capecitabine were enrolled. Ixabepilone 40 mg/m(2) monotherapy was administered as a 3-hour intravenous infusion on day 1 of a 21-day cycle. The primary end point was objective response rate (ORR), assessed by an independent radiology facility (IRF). RESULTS A total of 126 patients were treated and 113 were assessable for response. Patients were heavily pretreated: 88% had received at least two lines of prior chemotherapy in the metastatic setting. IRF-assessed ORR was 11.5% (95% CI, 6.3% to 18.9%) for response-assessable patients. Investigator-assessed ORR for all treated patients was 18.3% (95% CI, 11.9% to 26.1%). Fifty percent of patients achieved stable disease (SD); 14.3% achieved SD >or= 6 months. Median duration of response and progression-free survival were 5.7 and 3.1 months, respectively. Median overall survival was 8.6 months. Patients received a median of 4.0 treatment cycles (range, one to 16 cycles), and 25% of patients received >or= eight cycles. Grade 3/4 treatment-related events included peripheral sensory neuropathy (14%), fatigue/asthenia (13%), myalgia (8%), and stomatitis/mucositis (6%). Resolution of grade 3/4 peripheral sensory neuropathy occurred after a median period of 5.4 weeks. CONCLUSION Ixabepilone demonstrated clear activity and a manageable safety profile in patients with MBC resistant to anthracycline, taxane, and capecitabine. Responses were durable and notable in patients who had not previously responded to multiple prior therapies.

Randomized Trial of Black Cohosh for the Treatment of Hot Flashes Among Women With a History of Breast Cancer

PURPOSE Most breast cancer survivors experience hot flashes; many use complementary or alternative remedies for these symptoms. We undertook a randomized clinical trial of black cohosh, a widely used herbal remedy for menopausal symptoms, among breast cancer patients. PATIENTS AND METHODS Patients diagnosed with breast cancer who had completed their primary treatment were randomly assigned to black cohosh or placebo, stratified on tamoxifen use. At enrollment, patients completed a questionnaire about demographic factors and menopausal symptoms. Before starting to take the pills and at 30 and 60 days, they completed a 4-day hot flash diary. At the final visit, they completed another menopausal symptom questionnaire. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were measured in a subset of patients at the first and final visits. RESULTS Of 85 patients (59 on tamoxifen, 26 not on tamoxifen) enrolled in the study, 42 were assigned to treatment and 43 were assigned to placebo; 69 completed all three hot flash diaries. Both treatment and placebo groups reported declines in number and intensity of hot flashes; the differences between the groups were not statistically significant. Both groups also reported improvements in menopausal symptoms that were, for the most part, not significantly different. Changes in blood levels of FSH and LH also did not differ in the two groups. CONCLUSION Black cohosh was not significantly more efficacious than placebo against most menopausal symptoms, including number and intensity of hot flashes. Our study illustrates the feasibility and value of standard clinical trial methodology in assessing the efficacy and safety of herbal agents.

Phase II Clinical Trial of Ixabepilone (BMS-247550), an Epothilone B Analog, in Patients With Taxane-Resistant Metastatic Breast Cancer

PURPOSE Ixabepilone (BMS-247550) is an epothilone analog that optimizes the properties of naturally occurring epothilone B. Natural epothilones and their analogs promote tumor cell death by binding to tubulin and stabilizing microtubules, causing apoptosis. This international phase II trial assessed the activity of ixabepilone in patients with metastatic breast cancer (MBC) that was resistant to taxane therapy. PATIENTS AND METHODS MBC patients, who had experienced disease progression while receiving or within 4 months of taxane therapy (6 months if adjuvant taxane only), and who had a taxane as their last regimen, received ixabepilone (1- or 3-hour infusion of 50 mg/m(2) or 3-hour infusion of 40 mg/m(2) every 3 weeks). RESULTS Of 49 patients treated with 40 mg/m(2) ixabepilone during 3 hours, 35 (73%) had experienced disease progression within 1 month of their last taxane dose. The response rate was 12% (95% CI, 4.7% to 26.5%). All responses (n = 6) were partial; five of six patients had not responded to prior taxane therapy. In responders, the median response duration was 10.4 months. In 20 patients (41%), stable disease was the best outcome. Median time to progression was 2.2 months (95% CI, 1.4 to 3.2 months); median survival was 7.9 months. For treated patients across all cohorts (intent-to-treat population), the response rate was also 12% (eight of 66). Treatment-related adverse events in the study were manageable and primarily grade 1/2. Treatment-related neuropathy was mostly sensory and mild to moderate. CONCLUSION Ixabepilone (40 mg/m(2) as a 3-hour infusion every 3 weeks) demonstrates promising antitumor activity and an acceptable safety profile in patients with taxane-resistant MBC.

Phase II Clinical Trial of Ixabepilone (BMS-247550), an Epothilone B Analog, As First-Line Therapy in Patients With Metastatic Breast Cancer Previously Treated With Anthracycline Chemotherapy

PURPOSE There is a need for new agents to treat metastatic breast cancer (MBC) in patients for whom anthracycline therapy has failed or is contraindicated. This study was conducted to assess the efficacy and safety of the novel antineoplastic, the epothilone B analog ixabepilone, in patients with MBC previously treated with an adjuvant anthracycline. PATIENTS AND METHODS Patients were age >or= 18 years and had received a prior anthracycline-based regimen as adjuvant treatment. Ixabepilone as first-line metastatic chemotherapy was administered as a 40 mg/m(2) intravenous infusion during 3 hours every 3 weeks. The primary efficacy end point was objective response rate (ORR). Secondary efficacy end points included duration of response, time to response, time to progression, and survival. RESULTS All 65 patients were assessable for response. Their median age was 52 years (range, 33 to 80 years). ORR was 41.5% (95% CI, 29.4% to 54.4%), median duration of response was 8.2 months (95% CI, 5.7 to 10.2 months), and median time to response was 6 weeks (range, 5 to 17 weeks). Median survival was 22.0 months (95% CI, 15.6 to 27.0 months). Treatment-related adverse events were manageable and mostly grades 1/2: the most common of these (other than alopecia) was mild to moderate neuropathy, which was primarily sensory and mostly reversible in nature. CONCLUSION Ixabepilone is efficacious and has a predictable and manageable safety profile in women with MBC previously treated with an adjuvant anthracycline.

Microenvironmental Regulation of Epithelial–Mesenchymal Transitions in Cancer

The evolution of the cancer cell into a metastatic entity is the major cause of death in patients with cancer. Activation of the epithelial-to-mesenchymal transition (EMT) endows invasive and metastatic properties upon cancer cells that favor successful colonization of distal target organs. The observation that in many cancers distant metastases resemble the epithelial phenotype of primary tumors has led to speculation that the disseminated tumor cells recruited to the target organs undergo mesenchymal-to-epithelial transition (MET). However, the MET cascade has not been recapitulated in vivo, and the cellular and molecular regulators that promote MET remain unknown. In a recent report, using a model of spontaneous breast cancer, we have shown that bone marrow-derived myeloid progenitor cells in the premetastatic lung secrete the proteoglycan versican, which induces MET of metastatic tumor cells and accelerates metastases. This review summarizes recent progress in MET research, outlines a unique paracrine cross-talk between the microenvironment and the cancer cells, which promotes tumor outgrowth in the metastatic organ, and discusses opportunities for novel antimetastatic approaches for cancer therapy.

Breast Cancer Methylomes Establish an Epigenomic Foundation for Metastasis

Breast cancer methylomes contribute to metastatic potential, modulate the metastasis transcriptome, and predict disease outcome. Meditating on Breast Cancer People of diverse faiths and backgrounds have gained new mindsets when contemplating “Om” (or Aum)—a meditation symbol that represents the universe in its entirety. The concept of examining existence from a global perspective has begun to take hold in cancer research as well. Indeed, researchers have created their own “omes”: the genome, the transcriptome, the proteome. Here, Fang et al. examine the methylome of breast cancer and find a signature that may predict metastasis. The authors used genome-wide analysis to examine methylome signatures in breast cancers with various metastatic behaviors and found a signature that was associated with low metastatic risk and improved rates of survival. This breast CpG island methylator phenotype (B-CIMP) tracked with reduced metastasis independently of other breast cancer markers [such as estrogen receptor/progesterone receptor (ER/PR) and human epidermal growth factor receptor 2 (HER2) status] and was shared by multiple human malignancies, including glioma and colon cancer. However, altered methylation status may not just be a marker of metastasis: Methylation of B-CIMP signature genes correlated with transcriptional diversity among breast cancers with different prognoses. Thus, the B-CIMP phenotype may thus play a mechanistic role in metastatic risk, and future meditation on the methylome may improve breast cancer prognosis and therapy. Cancer-specific alterations in DNA methylation are hallmarks of human malignancies; however, the nature of the breast cancer epigenome and its effects on metastatic behavior remain obscure. To address this issue, we used genome-wide analysis to characterize the methylomes of breast cancers with diverse metastatic behavior. Groups of breast tumors were characterized by the presence or absence of coordinate hypermethylation at a large number of genes, demonstrating a breast CpG island methylator phenotype (B-CIMP). The B-CIMP provided a distinct epigenomic profile and was a strong determinant of metastatic potential. Specifically, the presence of the B-CIMP in tumors was associated with low metastatic risk and survival, and the absence of the B-CIMP was associated with high metastatic risk and death. B-CIMP loci were highly enriched for genes that make up the metastasis transcriptome. Methylation at B-CIMP genes accounted for much of the transcriptomal diversity between breast cancers of varying prognosis, indicating a fundamental epigenomic contribution to metastasis. Comparison of the loci affected by the B-CIMP with those affected by the hypermethylator phenotype in glioma and colon cancer revealed that the CIMP signature was shared by multiple human malignancies. Our data provide a unifying epigenomic framework linking breast cancers with varying outcome and transcriptomic changes underlying metastasis. These findings significantly enhance our understanding of breast cancer oncogenesis and aid the development of new prognostic biomarkers for this common malignancy.

Prevention of chemotherapy and radiation toxicity with glutamine

GOALS OF THE WORK Malignancy produces a state of physiologic stress that is characterized by a relative deficiency of glutamine, a condition that is further exacerbated by the effects of cancer treatment. Glutamine deficiency may impact on normal tissue tolerance to antitumor treatment, and may lead to dose reductions and compromised treatment outcome. Providing supplemental glutamine during cancer treatment has the potential to abrogate treatment-related toxicity. We reviewed the available data on the use of glutamine to decrease the incidence and severity of adverse effects due to chemotherapy and/or radiation in cancer patients. METHODS We performed a search of the MEDLINE database during the time period 1980-2003, and reviewed the English language literature of both human and animal studies pertaining to the use of glutamine in subjects with cancer. We also manually searched the bibliographies of published articles for relevant references. MAIN RESULTS The available evidence suggests that glutamine supplementation may decrease the incidence and/or severity of chemotherapy-associated mucositis, irinotecan-associated diarrhea, paclitaxel-induced neuropathy, hepatic veno-occlusive disease in the setting of high dose chemotherapy and stem cell transplantation, and the cardiotoxicity that accompanies anthracycline use. Oral glutamine supplementation may enhance the therapeutic index by protecting normal tissues from, and sensitizing tumor cells to chemotherapy and radiation-related injury. CONCLUSIONS The role of glutamine in the prevention of chemotherapy and radiation-induced toxicity is evolving. Glutamine supplementation is inexpensive and it may reduce the incidence of gastrointestinal, neurologic, and possibly cardiac complications of cancer therapy. Further studies, particularly placebo-controlled phase III trials, are needed to define its role in chemotherapy-induced toxicity.