A phase 2 study of sequential neoadjuvant chemotherapy with gemcitabine and doxorubicin followed by gemcitabine and cisplatin in patients with large or locally advanced operable breast cancer: results from long-term follow-up

Gemcitabine and doxorubicin in immunostimulatory monophosphoryl lipid A liposomes for treating breast cancer

Cancer therapy is increasingly shifting toward targeting the tumor immune microenvironment and influencing populations of tumor infiltrating lymphocytes. Breast cancer presents a unique challenge as tumors of the triple-negative breast cancer subtype employ a multitude of immunosilencing mechanisms that promote immune evasion and rapid growth. Treatment of breast cancer with chemotherapeutics has been shown to induce underlying immunostimulatory responses that can be further amplified with the addition of immune-modulating agents. Here, we investigate the effects of combining doxorubicin (DOX) and gemcitabine (GEM), two commonly used chemotherapeutics, with monophosphoryl lipid A (MPLA), a clinically used TLR4 adjuvant derived from liposaccharides. MPLA was incorporated into the lipid bilayer of liposomes loaded with a 1:1 molar ratio of DOX and GEM to create an intravenously administered treatment. In vivo studies indicated excellent efficacy of both GEM-DOX liposomes and GEM-DOX-MPLA liposomes against 4T1 tumors. In vitro and in vivo results showed increased dendritic cell expression of CD86 in the presence of liposomes containing chemotherapeutics and MPLA. Despite this, a tumor rechallenge study indicated little effect on tumor growth upon rechallenge, indicating the lack of a long-term immune response. GEM/DOX/MPLA-L displayed remarkable control of the primary tumor growth and can be further explored for the treatment of triple-negative breast cancer with other forms of immunotherapy.

A hyaluronic acid conjugate engineered to synergistically and sequentially deliver gemcitabine and doxorubicin to treat triple negative breast cancer

Combination chemotherapy is commonly used to treat advanced breast cancer. However, treatment success is often limited due to systemic toxicity. To improve therapeutic efficacy, polymer drug conjugates carrying synergistic pairs of chemotherapy drugs can be used to reduce drug administration dose. Here, we systematically evaluated the effect of temporal scheduling of doxorubicin (DOX) and gemcitabine (GEM) on drug synergy. Hyaluronic acid (HA) drug conjugates with distinct linkers conjugating both DOX and GEM were synthesized to control relative release kinetics of each drug. We show that polymer conjugates that release GEM faster than DOX are more effective at killing triple negative breast cancer cells in vitro. We further show that the optimal dual drug conjugate more effectively inhibits the growth of an aggressive, orthotopic 4T1 tumor model in vivo than free DOX and GEM and the single drug HA conjugates. The dual drug HA conjugate can inhibit 4T1 tumor growth in vivo during treatment through both intravenous and non-local subcutaneous injections. These results emphasize the importance of understanding the effect release rates have on the efficacy of synergistic drug carriers and motivate the use of HA as a delivery platform for multiple cancer types.

Snail-induced epithelial-to-mesenchymal transition of MCF-7 breast cancer cells: systems analysis of molecular changes and their effect on radiation and drug sensitivity

Background

Epithelial-to-mesenchymal transition (EMT) has been associated with the acquisition of metastatic potential and the resistance of cancer cells to therapeutic treatments. MCF-7 breast cancer cells engineered to constitutively express the zinc-finger transcriptional repressor gene Snail (MCF-7-Snail cells) have been previously shown to display morphological and molecular changes characteristic of EMT. We report here the results of a comprehensive systems level molecular analysis of changes in global patterns of gene expression and levels of glutathione and reactive oxygen species (ROS) in MCF-7-Snail cells and the consequence of these changes on the sensitivity of cells to radiation treatment and therapeutic drugs.

Methods

Snail-induced changes in global patterns of gene expression were identified by microarray profiling using the Affymetrix platform (U133 Plus 2.0). The resulting data were processed and analyzed by a variety of system level analytical methods. Levels of ROS and glutathione (GSH) were determined by fluorescent and luminescence assays, and nuclear levels of NF-κB protein were determined by an ELISA based method. The sensitivity of cells to ionizing radiation and anticancer drugs was determined using a resazurin-based cell cytotoxicity assay.

Results

Constitutive ectopic expression of Snail in epithelial-like, luminal A-type MCF-7 cells induced significant changes in the expression of >7600 genes including gene and miRNA regulators of EMT. Mesenchymal-like MCF-7-Snail cells acquired molecular profiles characteristic of triple-negative, claudin-low breast cancer cells, and displayed increased sensitivity to radiation treatment, and increased, decreased or no change in sensitivity to a variety of anticancer drugs. Elevated ROS levels in MCF-7-Snail cells were unexpectedly not positively correlated with NF-κB activity.

Conclusions

Ectopic expression of Snail in MCF-7 cells resulted in morphological and molecular changes previously associated with EMT. The results underscore the complexity and cell-type dependent nature of the EMT process and indicate that EMT is not necessarily predictive of decreased resistance to radiation and drug-based therapies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2274-5) contains supplementary material, which is available to authorized users.

Multifunctional polymersomes for cytosolic delivery of gemcitabine and doxorubicin to cancer cells

Although liposomes are widely used as carriers of drugs and imaging agents, they suffer from a lack of stability and the slow release of the encapsulated contents at the targeted site. Polymersomes (vesicles of amphiphilic polymers) are considerably more stable compared to liposomes; however, they also demonstrate a slow release for the encapsulated contents, limiting their efficacy as a drug-delivery tool. As a solution, we prepared and characterized echogenic polymersomes, which are programmed to release the encapsulated drugs rapidly when incubated with cytosolic concentrations of glutathione. These vesicles encapsulated air bubbles inside and efficiently reflected diagnostic-frequency ultrasound. Folate-targeted polymersomes showed an enhanced uptake by breast and pancreatic-cancer cells in a monolayer as well as in three-dimensional spheroid cultures. Polymersomes encapsulated with the anticancer drugs gemcitabine and doxorubicin showed significant cytotoxicity to these cells. With further improvements, these vesicles hold the promise to serve as multifunctional nanocarriers, offering a triggered release as well as diagnostic ultrasound imaging.