Gemcitabine for the treatment of metastatic breast cancer

A Retrospective Look at Anti-EGFR Agents in Pancreatic Cancer Therapy

Background:

The introduction of Monoclonal Antibodies (mAbs) and small-molecule Tyrosine Kinase Inhibitors (TKIs) that target the Epidermal Growth Factor Receptor (EGFR), marks a huge step forward in the Pancreatic Cancer (PC) therapy. However, anti-EGFR therapy is found to be successful only in a fraction of patients. Although anti-EGFR agents have shown considerable clinical promise, a serious adverse event associated with anti- EGFR therapy has been challenging. At this juncture, there is still more to be done in the search for effective predictive markers with therapeutic applicability.

Methods:

A focused literature search was conducted to summarize the existing evidence on anti-EGFR agents in pancreatic cancer therapy.

Results:

This review discusses various anti-EGFR agents currently in use for PC therapy and potential adverse effects associated with it. Existing evidence on EGFR TKIs demonstrated better tolerant effects and outcomes with multiple toxic regimens. Anti-EGFR therapy in combination with chemotherapy is necessary to achieve the best clinical outcomes.

Conclusion:

Future prospective studies on the identification of additional biological agents and novel anti-EGFR agents are warranted.

Silencing of TRPM8 inhibits aggressive tumor phenotypes and enhances gemcitabine sensitivity in pancreatic cancer

The transient receptor potential TRPM8 ion channel is required for cellular proliferation in pancreatic epithelia and adenocarcinoma. To elucidate the mechanism that mediates the function of TRPM8, we examined its role in the proliferation and invasion of pancreatic cancer (PC) cells. TRPM8 expression increased in both the PC tissues and cell lines; a high TRPM8 expression was correlated with poorer prognosis in patients with PC. In PC cell lines, PACN-1 and BxPC-3, Ca²⁺ influxes could be evoked by TRPM8; the sensitivity of PC cells to gemcitabine was increased, while the proliferation and invasion of PC cells were suppressed after RNA interference-mediated silencing of TRPM8. The mechanism of TRPM8 in gemcitabine-based chemotherapy was then investigated. The expression and activity of multidrug resistance-associated proteins, P-gp, MRP-2, LRP, was significantly reduced in response to TRPM8 silence. Moreover, TRPM8 knockdown significantly increased hENT1 protein levels and the ratio of Bax/Bcl-2 while decreased the protein levels of RRM1. Thus, TRPM8 is required for PC cell proliferation and invasion and was closely related to the gemcitabine sensitivity of PC. The modulation of TRPM8 expression may help improve treatment response of PC by combining with traditional chemotherapy.

Efficacy and safety of eribulin in taxane-refractory patients in the ‘real world’

Aim: Recent clinical, randomized and observational studies showed that eribulin, an analogous of Halichondrin B, was beneficial and well-tolerated in heavily pretreated metastatic breast cancer patients. Here, we aim to evaluate the effectiveness and safety of eribulin in taxane-refractory metastatic breast cancer patients. Patients & methods: In this subanalysis of the ESEMPIO study database, we selected 91 subjects with well-defined taxane refractoriness and complete data available. Results: 41 patients (45.2%) showed clinical benefit; one complete response (2.2%) and 16 partial responses (17.6%) were observed. Median progression-free survival and median overall survival were 3.1 and 11.6 months, respectively. The most experienced adverse event was asthenia/fatigue (58%), followed by neutropenia (30%). The treatment-related toxicity led to eribulin-dose reduction in 19 patients and suspension in nine. Conclusion: This study shows that eribulin is effective and well tolerated also in taxane-refractory patients in clinical practice.

Hyaluronan-conjugated liposomes encapsulating gemcitabine for breast cancer stem cells

Investigation of potential therapeutics for targeting breast cancer stem cells (BCSCs) is important because these cells are regarded as culprit of breast cancer relapse. Accomplishing this kind of strategy requires a specific drug-delivery system using the distinct features of liposomes. Studies on targeted liposomal delivery systems have indicated the conjugation of hyaluronan (HA), a primary ligand for CD44 surface markers, as an appropriate method for targeting BCSCs. For this study, enriched BCSCs were obtained by culturing MCF-7 breast cancer cells in nonadherent conditions. The enriched BCSCs were challenged with HA-conjugated liposomes encapsulating gemcitabine (2, 2-difluoro-2-deoxycytidine, GEM). In vitro study showed that the HA-conjugated liposomes significantly enhanced the cytotoxicity, anti-migration, and anti-colony formation abilities of GEM through targeting of CD44 expressed on BCSCs. In pharmacokinetic study, area under the drug concentration vs time curve (AUC) of the immunoliposomal GEM was 3.5 times higher than that of free GEM, indicating that the HA-conjugated liposomes enhanced the stability of GEM in the bloodstream and therefore prolonged its half-life time. The antitumor effect of the immunoliposomal GEM was 3.3 times higher than that of free GEM in a xenograft mouse model, probably reflecting the unique targeting of the CD44 receptor by HA and the increased cytotoxicity and stability through the liposomal formulation. Furthermore, marginal change in body weight demonstrated that the use of liposomes considerably reduced the systemic toxicity of GEM on normal healthy cells. Taken together, this study demonstrates that HA-conjugated liposomes encapsulating GEM show promise for the therapy of breast cancer in vitro and in a xenograft model by targeting the BCSCs.

Hypoxia-induced deoxycytidine kinase expression contributes to apoptosis in chronic lung disease

Chronic obstructive pulmonary disease (COPD) is characterized by persistent inflammation and tissue remodeling and is a leading cause of death in the United States. Increased apoptosis of pulmonary epithelial cells is thought to play a role in COPD development and progression. Identification of signaling pathways resulting in increased apoptosis in COPD can be used in the development of novel therapeutic interventions. Deoxyadenosine (dAdo) is a DNA breakdown product that amplifies lymphocyte apoptosis by being phosphorylated to deoxyadenosine triphosphate (dATP). dAdo is maintained at low levels by adenosine deaminase (ADA). This study demonstrated that mice lacking ADA developed COPD manifestations in association with elevated dAdo and dATP levels and increased apoptosis in the lung. Deoxycitidine kinase (DCK), a major enzyme for dAdo phosphorylation, was up-regulated in mouse and human airway epithelial cells in association with air-space enlargement. Hypoxia was identified as a novel regulator of DCK, and inhibition of DCK resulted in diminished dAdo-mediated apoptosis in the lungs. Our results suggest that activating the dAdo-DCK-dATP pathway directly results in increased apoptosis in the lungs of mice with air-space enlargement and suggests a novel therapeutic target for the treatment of COPD.

The economic burden of metastatic breast cancer: a systematic review of literature from developed countries

OBJECTIVE

Breast cancer, the most common malignant cancer among women in Western countries, has poor prognosis following metastasis. New therapies potentially extend survival, but their value is questioned when benefits are incremental and expensive. The objective of our study was to understand the economic impact of metastatic breast cancer (MBC) and its treatment, and to evaluate the designs of these studies.

METHODS

We systematically reviewed the MEDLINE-indexed, English-language literature, identifying 31 articles on the economic evaluation of MBC in 10 developed countries, including studies of per-patient costs, gross national costs, and cost-effectiveness models. We also included health technology assessments (HTAs) from government and regulatory agencies.

RESULTS

Total per-patient costs of MBC are only available for Sweden ($17,301-$48,169 annually, depending on patient age (2005 USD)). Most economic analyses of per-patient direct costs originate from the US; across all countries, data indicate that this burden is substantial. Gross national costs of MBC are available only for the UK (cost of incident MBC cases is estimated to be $22 million annually (2002 GBP)). Many cost-effectiveness analyses suggest that a number of new and established treatments are cost-effective compared to standard care in various countries, but many offer small increments in survival. The cost-effectiveness of trastuzumab, capecitabine, and nab-paclitaxel has been evaluated in many recent studies.

CONCLUSION

Most economic evaluations of MBC have utilized secondary rather than primary data, and have used scenarios and assumptions which may be inaccurate or outdated. The quality of evidence disseminated to decision-makers could be improved by adherence to best practices in cost-effectiveness analyses.