(193g) Development of HER2-Postive Breast Tumor Spheroids As a Better Approach to Study the Effectiveness of Novel Anticancer Therapies

Until these days, one of the first steps in the development of novel anticancer therapies has been the in vitro validation of their pharmaceutical activity in 2D cell cultures. However, the limitations of such kind of cultures are now well known: cells are force to polarize for being anchored to a rigid and a flat surface and they are super-nourished and super-oxygenated. As consequence, modifications in their orientation, in the expression of membrane receptors and in the production of extracellular matrix (ECM) take place. Moreover, it has been demonstrated that 2D cultures promote the immortalization of cancer cells, favoring the survival of those who divide faster but are less resistant to chemotherapy. Thus, taking into account all these disadvantages, understanding why most successful 2D studies do not have proper in vivo results is easier and the need of the implementation of novel validation methods is clear.

In this context, numerous research groups have already started to develop tumor spheroids, i.e., 3D cancer cell cultures that mimic natural tumor conditions, growth in special gels or matrix [1]. They are usually characterized by fluorescence microscopy and it can be found in literature that this type of cultures has helped to study hypoxia conditions inside tumors, the angiogenesis process [2], the importance of cell plasticity in tumor malignancy progression [3] and the pharmaceutical action of different anticancer drugs [4].

The work here presented is related with this last application. Spheroids of HER-2 positive metastasic breast cancer cells (BT474 cell line) have been developed in both, DMEM/F12, supplemented with B27, hEGF, insulin and hydrocortisone, and in a Matrigel® matrix. Their growth has been checked by optic microscopy and they have been characterized by confocal fluorescence microscopy. Finally, the efficacy of a novel paclitaxel and Trastuzumab vehicle, consisting on nanoparticles of alginate and piperazine [5] with the mentioned drug and antibody attached to their surface, has been validated with these breast cancer spheroids and results have been compared to nanoparticles´ antitumor effect in conventional 2D cultures. In this manner, the establishment of a more accurate in vitro validation method is pretended, useful to validate different therapeutic agents with results closer to that got with in vivo studies.

References

[1] Alemany-Ribes M., Semino C.E. Adv. Drug Deliv. Rev., 2014, 79-80, 40-49.

[2] Benton G., Arnaoutova I., George J., Kleinman H.K., Koblinski J. Adv. Drug Deliv. Rev., 2014, 79-80, 3-18.

[3] Liang Y., Jeong J., DeVolder R.J., Cha C., Wang F., Tong Y.W., Kong H. Biomaterials, 2011, 32, 9308-9315.

[4] Gurski L.A., Jha A.K., Zhang C., Jia X, Farach-Carson M.C. Biomaterials, 2009, 30, 6076-6085.

[5] Román J.V., Rodríguez- Rodríguez J.A., Martín Del Valle E.M., Galán M.A. Polymer Adv. Tech., 2016, 27(5), 623-629.