Experimental Models as Refined Translational Tools for Breast Cancer Research

Abstract

Breast cancer is one of the most common cancers worldwide, which makes it a very impactful malignancy in the society. Breast cancers can be classified through different systems based on the main tumor features and gene, protein, and cell receptors expression, which will determine the most advisable therapeutic course and expected outcomes. Multiple therapeutic options have already been proposed and implemented for breast cancer treatment. Nonetheless, their use and efficacy still greatly depend on the tumor classification, and treatments are commonly associated with invasiveness, pain, discomfort, severe side effects, and poor specificity. This has demanded an investment in the research of the mechanisms behind the disease progression, evolution, and associated risk factors, and on novel diagnostic and therapeutic techniques. However, advances in the understanding and assessment of breast cancer are dependent on the ability to mimic the properties and microenvironment of tumors in vivo, which can be achieved through experimentation on animal models. This review covers an overview of the main animal models used in breast cancer research, namely in vitro models, in vivo models, in silico models, and other models. For each model, the main characteristics, advantages, and challenges associated to their use are highlighted.

The past, present, and future of breast cancer models for nanomedicine development

“…The selection of adequate model systems for each stage represents a tricky balancing act, with cost-effectiveness, difficulty, and ethical concerns “weighed up” against the potential for providing relevant data. Immortalized cell lines represent the most cost-effective and simplistic tumor models, and despite the alterations that cell lines undergo during their establishment and prolonged culture, breast cancer cell lines tend to maintain the major genetic alterations corresponding to the tumor subtype, thereby validating their implementation in tumor models [62] , [63] . Even though a large number of human breast cancer cell lines exist for research purposes, studies tend to employ a core set that includes the human MCF7 (luminal A subtype) and MDA-MB-231 (TNBC subtype) [62] cell lines, and the mouse 4T1 (TNBC subtype) cell line [64] .…”

A Step Forward in Breast Cancer Research: From a Natural-Like Experimental Model to a Preliminary Photothermal Approach

“…However, it must be kept in mind that the cells receptors expression of these cells was not assessed. And even though, according to the literature both cell lines overexpress EGFR [ 61 , 98 ], it is also known that upon subsequent cell replications the probability of occurring genomic changes and mutation increases [ 29 ]. When comparing the results from the two cell-lines it is clear that the combined treatment had a far better efficacy over MCF-7 cells than MDA-MB-231 cells, thus requiring complementary further tests to clarify the mechanisms underlying these findings.…”

“…Experimental models are crucial tools to unveil breast cancer features, and to develop and evaluate potential diagnostic and new therapeutic strategies. A vast list of experimental models has been proposed [ 29 , 30 ], including, for instance, in vitro [ 31 , 32 ] and in vivo models. The choice of the most suitable model is not easy, and it depends on the researcher’s preference and background knowledge, on the resources and infrastructures available, on the purpose/focus of the study and on the ethical concerns inherent to the use of biological samples.…”

“…However, they require the use of immunocompromised animals, which do not mimic a real scenario and makes these models very expensive. On the other hand, chemically-induced models are cheaper models that result in more heterogeneous tumors with longer latency, whose development is harder to control [ 29 ]. However, they are especially useful to understand the impact of certain chemicals, to which people might be exposed to in their routine, on breast cancer initiation, promotion and progression [ 5 , 40 , 41 ].…”

Cytotoxic T cells response with decreased CD4/CD8 ratio during mammary tumors inhibition in rats induced by non-contact electric fields

“…A total of 40 5-week-old healthy female Sprague Dawley (SD) rats (Rattus norvegicus, Berkenhout 1769) weighing 50−80 gram were used for this study. SD rats have been used as animal tumor model to study human breast cancer with various induction agents, as well as with DMBA administration 23,24 , since rats have 98% genetic homology with humans 25 . The rats were supplied by LPPT UGM laboratory, Yogyakarta, Indonesia, and never used for any other experiment.…”