Optical imaging detection of microscopic mammary cancer in ErbB‐2 transgenic mice through the DA364 probe binding α_vβ₃ integrins

Abstract

Despite spontaneous tumor growth in genetically engineered mice being one of the most recognized tools for the in vivo evaluation of novel diagnostic and therapeutic anticancer compounds, monitoring early stage lesions in live animals is a goal that has yet to be achieved. A large number of targets for the molecular imaging of various diseases have been identified and many imaging technologies, including optical techniques are emerging. One of the most commonly exploited targets in tumor imaging is αv β3 integrin, which plays an important role in the expansion, invasiveness and metastatic capability of a number of cancers, including breast cancer. The aim of this study was to set up an optical imaging method for the early detection of autochthonous mammary cancer in female BALB/c mice transgenic for the rat-ErbB-2 oncogene (BALB-neuT). We show that DA364, a near-infrared fluorescence arginine-glycine-aspartic acid cyclic probe, was taken up by neoplastic mammary glands and that its uptake increased with cancer progression. By contrast, the nonaccumulation of DA364 in the healthy mammary glands of virgin and lactating wild-type mice suggests that the probe specifically targets breast cancers. Comparisons of optical imaging with whole-mount and histological findings showed that DA364 allows the noninvasive visualization of atypical hyperplasia and microscopic foci of in situ carcinoma 2 months before mammary lesions become detectable by palpation. Moreover, DA364 was successfully used to monitor the outcome of anticancer vaccination. Therefore, it can be considered a promising early detection tool in near-infrared noninvasive optical imaging for the early diagnosis of breast cancer.

Microenvironment, Oncoantigens, and Antitumor Vaccination: Lessons Learned from BALB-neuT Mice

“…In this context, we have recently demonstrated that both ECs and cancer cells in mammary tumors arising in BALB-neuT mice express α v β 3 integrin, a receptor for several extracellular matrix proteins which harbor an arginine-glycine-aspartic acid (RGD) sequence [98]. α v β 3 integrin is widely considered to be a marker of the angiogenesis, tumor progression, and invasion of different types of cancer.…”

“…α v β 3 integrin is widely considered to be a marker of the angiogenesis, tumor progression, and invasion of different types of cancer. Since its level of expression correlates with cancer progression [99], we have developed a probe for the optical imaging detection of α v β 3 integrin and have shown that it can successfully detect microscopic in situ carcinomas in BALB-neuT mice, therefore proving itself to be a promising tool for the early diagnosis of breast cancer [98]. …”

“…It has also been proposed that the autocrine production of OPN by tumor cells may be an important factor that allows invasion and survival to occur [167]. In fact, the interaction between extracellular matrix deposited OPN and cell adhesion molecules, such as α v β 3 integrins which are overexpressed in BALB-neuT tumors [98], increases both the expression of VEGF in ECs, allowing neovascularization, and the activation of connective tissue growth factor and cysteine-rich angiogenic inducer 61(CYR61), which enhances neovascularization and mammary tumor growth in vivo [168]. …”

A Mathematical-Biological Joint Effort to Investigate the Tumor-Initiating Ability of Cancer Stem Cells

“…TUBO epithelial cells (an ErbB2 + cloned cell line established from a mammary carcinoma arising in a BALB-neuT female mouse [31],[32]) were cultured in DMEM supplemented with 20% FBS. To generate non-adherent spherical clusters of cells (mammospheres), TUBO cells were detached and plated in ultra-low attachment flasks (Sigma-aldrich) at 6×10 4 viable cells/ml in mammosphere medium.…”

Genetically Engineered Mice as Experimental Tools to Dissect the Critical Events in Breast Cancer

“…Near-infrared non invasive optical imaging was also used for detection of microscopic mammary cancer in ErbB2 transgenic mice (Conti et al, 2013). DA364, a near-infrared fluorescence arginine-glycine-aspartic acid cyclin probe that binds the integrin α v β 3 and is then taken up specifically by cancer cells was utilized for imaging.…”