Edelfosine: An Antitumor Drug Prototype

BACKGROUND

Lung cancer is the most prevalent cancer and a high fatality disease. Despite of all available therapeutic approaches, drug resistance of chemotherapy agents for patients remain as an obstacle. New drugs integrating immunotherapeutic and conventional cytotoxic effects is a powerful strategy for the treatment of cancer to overcome this limitation. Antineoplastic phospholipids combine both of these activities by affecting lipid metabolism and signaling through lipid rafts. Therefore, they emerge as interesting scaffolds for designing new drugs.

OBJECTIVE

We aimed to evaluate antineoplastic phospholipids as scaffolds for designing new drugs for lung cancer treatment.

METHODS

The initial screening in A549 cells was performed by MTT assay. Others cytotoxic effects were evaluated in A549 cells by clonogenic assay, Matrigel 3D culture and flow cytometry analyses of cell cycle, apoptosis, mitochondrial membrane electronic potential and superoxide production. Immunological effects of ED were accessed on dendritic cells (DCs) and the expression of some markers were evaluated by flow cytometry. In vivo lung colonization analysis was performed after intravenously injection of A549 cells and daily treatment with ED.

RESULTS

Herein, ED showed to be the most efficient compound concerning cytotoxic, thereby, ED was selected for following tests. ED showed a cytotoxic profile in both monolayer and 3D culture and also in vivo models using A549 cells. This profile is due to G0/G1 phase cellular arrest and apoptosis drove by mitochondrial membrane depolarization and superoxide overproduction. Moreover, ED modulated DCs toward an activated pattern by the increased expression of CD83 and a remarkable decreased expression of PD-L1/CD274 on DCs membrane.

CONCLUSIONS

Thus, ED is an interesting antitumor drug prototype due to not only its direct cellular cytotoxicity but also given its immunological features.

Phosphoethanolamine induces caspase-independent cell death by reducing the expression of C-RAF and inhibits tumor growth in human melanoma model

Phosphoethanolamine (PEA) is a fundamental precursor during the biosynthesis of cell membranes phospholipids. In the past few years, it has been described as a potential antitumor agent. In previous studies, we demonstrated that PEA showed antitumor properties in vitro and in vivo in a wide range of tumor cell lines. Herein, we showed that PEA possesses cytotoxic properties and notably revealed to induce caspase-independent cell death. Of interest, we provided evidence that PEA inhibits melanoma cells proliferation through the reduction of C-RAF. Molecular docking of PEA evidenced that this compound indeed fits satisfactory in the binding site located between the dimers of C-RAF protein with 107,01 Å and score of -29,62. Also, PEA arrested A2058 cells at G2/M phase in the cell cycle. Moreover, cell proliferation, migration and adhesion capacities of A2058 cells were also inhibited by PEA. Most importantly, PEA inhibited tumor growth of melanoma tumors and prolonged survival rate of mice. Also, PEA induced a significant immune response in a syngeneic metastatic melanoma model. Taken together, these data indicate that PEA is a promising candidate for future developments in cancer field.

Intervening in disease through genetically-modified bacteria

The comprehension of the molecular basis of different diseases is rapidly being dissected as a consequence of advancing technology. Consequently, proteins with potential therapeutic usefulness, including cytokines and signaling molecules have been identified in the last decades. However, their clinical use is hampered by disadvantageous functional and economic considerations. One of the most important of these considerations is targeted topical delivery and also the synthesis of such proteins, which for intravenous use requires rigorous purification whereas proteins often do not withstand digestive degradation and thus cannot be applied per os. Recently, the idea of using genetically modified bacteria has emerged as an attempt to evade these important barriers. Using such bacteria can deliver therapeutic proteins or other molecules at place of disease, especially when disease is at a mucosal surface. Further, whereas intravenously applied therapeutic proteins require expensive methodology in order to become endotoxin-free, this is not necessary for local application of therapeutic proteins in the intestine. In addition, once created further propagation of genetically modified bacteria is both cheap and requires relatively little in conditioning with respect to transport of the medication, making such organisms also suitable for combating disease in developing countries with poor infrastructure. Although first human trials with such bacteria were already performed more as a decade ago, the recent revolution in our understanding of the role of human gut microbiome in health and diseases has unleashed a revolution in this field resulting in a plethora of potential novel prophylactic and therapeutic intervention against disease onset and development employing such organisms. Today, the engineering of human microbiome for health benefits and related applications now chances many aspects of biology, nanotechnology and chemistry. Here, we review genetically modified bacteria methodology as possible carriers of drug delivering and provided the origin and inspirations for new drug delivery systems.

Early-onset breast cancer patients in the South and Southeast of Brazil should be tested for the TP53 p.R337H mutation

Germline TP53 mutations are associated with Li-Fraumeni syndrome (LFS), a disease that predisposes carriers to a wide variety of early onset tumors. In southern and southeastern Brazil, a high frequency of a germline TP53 mutation, p.R337H, was diagnosed in 0,3% of the population due to a founder effect. Carriers are at risk for developing cancer but the penetrance is lower than in typical DNA binding domain mutations. To date, only a few families were detected and diagnosis of carriers remains a challenge. Therefore, the inclusion of additional criteria to detect p.R337H carriers is necessary for the Brazilian population. We assessed the A.C. Camargo Cancer Center Oncogenetics Department database in search of common characteristics associated with p.R337H families that did not fulfill LFS/LFL clinical criteria. Among 42 p.R337H families, three did not meet any LFS/LFL criteria. All cases were young female patients with breast cancer diagnosed before age 45 and with no family history of LFS linked-cancers. Our results suggest that screening for the germline TP53 p.R337H mutation should be indicated, along with BRCA1 and BRCA2 genetic testing, for this group of patients, especially in the South and Southeast of Brazil.

Changes in expression pattern of selected endometrial proteins following mesenchymal stem cells infusion in mares with endometrosis

Mesenchymal stem cells (MSCs) due to their self-renewal potential and differentiation capacity are useful for tissue regeneration. Immunomodulatory and trophic properties of MSCs were demonstrated suggesting their use as medicinal signaling cells able to positively change local environment in injured tissue. Equine endometrosis is a progressive degenerative disease responsible for glandular alterations and endometrial fibrosis which causes infertility in mares. More precisely, this disease is characterized by phenotypic changes in the expression pattern of selected endometrial proteins. Currently, no effective treatment is available for endometrosis. Herein, we aimed at the evaluation of expression pattern of these proteins after allogeneic equine adipose tissue-derived multipotent mesenchymal stem cells (eAT-MSCs) infusion as well as at testing the capacity of these cells to promote endometrial tissue remodeling in mares with endometrosis. eAT-MSC (2×10⁷/animal) were transplanted into mares’ uterus and control animals received only placebo. Uterine biopsies were collected before (day 0) and after (days 7, 21 and 60) cells transplantation. Conventional histopathology as well as expression analysis of such proteins as laminin, vimentin, Ki-67-antigen, α-smooth muscle actin (α-SMA) and cytokeratin 18 (CK18) have been performed before and after eAT-MSCs transplantation. We demonstrated that eAT-MSCs induced early (at day 7) remodeling of endometrial tissue microenvironment through changes observed in intra cellular and intra glandular localization of aforementioned proteins. We demonstrated that eAT-MSCs were able to positively modulate the expression pattern of studied secretory proteins as well as, to promote the induction of glandular epithelial cells proliferation suggesting local benefits to committed endometrial tissue environment after eAT-MSCs transplantation.

Abstract 3771: Establishment of primary cultures of cancer stem cells from patients with Li-Fraumeni Syndrome, carrier of TP53 p.R337H Brazilian founder mutation

Li-Fraumeni syndrome (LFS), an inherited cancer predisposition syndrome, is associated with germline mutations in TP53. It is characterized by high risk of multiple, early cancers. In Brazil, a variant form of LFS is exceedingly frequent due to a widespread founder TP53 mutation, p.R337H, detected in about 0.3% of the general population in Southern Brazil. This mutation occurs in p53 oligomerization domain and its effect on p53 oligomerization is supposed to be dependent upon pH conditions. Recent studies indicate that p53 plays a critical role in regulating differentiation and asymmetric divisions of stem cells. The main objective of this study is to isolate and to characterize Cancer Stem Cells (CSC) in patients with germline mutations in TP53 gene with Li-Fraumeni syndrome and Li-Fraumeni-like Syndrome. We have isolated and characterized CSC from tumors of p.R337H mutation carriers. After informed consent, surgical resection fragments were dissociated and brought in culture. Adherent cells and spheroids were derived from different tumor types. Spheroids and stromal cells derived from a breast cancer (BC) were further analyzed by immunofluorescence and flow cytometry to demonstrate positive immunolabeling for CD44+, CD24−, Oct4, Ki67 and Sox2 antibodies. Time-lapse videomicroscopy showed rapid growth, frequent asymmetric division and absence of senescent phenotypes for least 17 passages. Moreover, we showed by Colony Forming Units assay (CFU) that stromal cells are very clonogenic, once 103 cells initially plated were able to form 442 new colonies after 15 days in culture. It was also verified the differentiation potential of stromal cells for the following lineages: adipogenic, osteogenic and muscle-like cells. The adherent stromal cells as well as oncoesferas are able to self-renew and to proliferate in vitro for long periods without losing its main features. These properties are similar to stem cell possessing the p53 inactive. However, we observed that treatment of adherent cells with doxorubicin (DNA damaging agent) causes accumulation of p53 and causing induction of cell cycle arrest with low doses of this drug, and cell death / apoptosis in higher doses. Our findings using CSC-p.R337H can provide a very useful model for better understanding the role of specific mutation, as well as the TP53 tumor biology.

Citation Format: Lisley I. Mambelli, Irina Kerkis, Pierre Hainaut, Maria Isabel W. Achatz. Establishment of primary cultures of cancer stem cells from patients with Li-Fraumeni Syndrome, carrier of TP53 p.R337H Brazilian founder mutation. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3771. doi:10.1158/1538-7445.AM2013-3771

Abstract 5349: Cancer stem cells isolation and characterization from breast tumor of a germline carrier of TP53 p.R337H (Brazilian founder) mutation

Li-Fraumeni syndrome (LFS), an inherited cancer predisposition syndrome, is associated with germ line mutations in TP53. It is characterized by high risk of multiple, early cancers. In Brazil, a variant form of LFS is exceedingly frequent due to a widespread founder TP53 mutation, p.R337H, detected in about 0.3% of the general population in Southern Brazil. This mutation occurs in p53 oligomerization domain and its effect on p53 oligomerization is supposed to be dependent upon pH conditions. We have isolated and characterized Cancer Stem Cells from tumors of p.R337H mutation carriers. After informed consent and surgical resection fragments were dissociated and brought in culture. Adherent cells and spheroids were derived from different tumor types. Spheroids derived from a breast cancer (BC) were further analyzed to demonstrate positive immunolabeling for CD44, CD24, Oct4 and Sox2 antibodies. Time-lapse videomicroscopy showed rapid growth, frequent asymmetric division and absence of senescent phenotypes for least 17 passages. At confluence, some cells spontaneously differentiated into adipogenic and muscle-like cells. Floating and adherent spheroids contained self-renewing cells capable of long-term proliferation without losing their primary characteristics. These properties are similar to those of stem cells with inactivated p53 protein. However, treatment of adherent cells with the DNA damaging agent doxorubicin elicited p53 accumulation, p21 induction, cell cycle arrest at low doses of Dox and cell death/apoptosis at higher doses. These results are consistent with the notion that p.R337H may retain a quasi-normal p53 function in response to stress while expressing properties similar to mutant p53 in long-term CSC culture. These p.R337H CSC may provide a very useful model for studying the defects underlying inherited cancer in p.R337H carriers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5349. doi:1538-7445.AM2012-5349