Cancer Biology

Recurrent hormone receptor-positive (HR+) breast cancer is a leading cause of cancer mortality in women. Recurrence and resistance to targeted therapies have been difficult to study due to the long clinical course of the disease, the complex nature of resistance, and the lack of clinically relevant model systems. Existing models are limited to a few HR+ cell lines, organoid models, and patient-derived xenograft models, all lacking components of the human tumor microenvironment. Furthermore, the low take rate and loss of estrogen receptor (ER) expression in patient-derived organoids (PDOs) has been challenging. Our protocol allows simultaneous isolation of PDOs and matching cancer-associated fibroblasts (CAFs) from primary and metastatic HR+ breast cancers. Importantly, our protocol has a higher take rate and enables long-term culturing of PDOs that retain ER expression. Our matching PDOs and CAFs will provide researchers with a new resource to study the influence of the tumor microenvironment on various aspects of cancer biology such as cell growth and drug resistance in HR+ breast cancer.

Murine tumor models have been critical to advances in our knowledge of tumor physiology and for the development of effective tumor therapies. Essential to these studies is the ability to both track tumor development and quantify tumor burden in vivo. For this purpose, the introduction of genes that confer tumors with bioluminescent properties has been a critical advance for oncologic studies in rodents. Methods of introducing bioluminescent genes, such as firefly luciferase, by viral transduction has allowed for the production of tumor cell lines that can be followed in vivo longitudinally over long periods of time. Here we describe methods for the production of stable luciferase expressing tumor cell lines by lentiviral transduction.

Medullary thyroid cancers (MTCs) are derived from calcitonin-producing cells (C cells) of neuroendocrine origin. Rb heterozygous mice develop low-grade C cell adenocarcinoma following biallelic inactivation of the Rb tumor suppressor gene loci. Additional inactivation of another tumor suppressor gene such as Trp53, Arf or Cdkn1a allows Rb-deficient mice to generate more aggressive C cell adenocarcinoma (Takahashi et al., 2006; Shamma et al., 2009; Kitajima et al., 2015). To characterize C cell adenocarcinoma cells derived from Rb-deficient mice of different genetic backgrounds, we attempted to extract C cell adenocarcinoma cells from primary thyroid tumor tissue. Since primary mouse small cell lung cancer (SCLC) cells those originate in neuroendocrine cells that also stems C cells, can be established both as non-adhesive and adhesive cells (Calbo et al., 2011), we applied their method to MTCs. Here we describe our isolation technique for non-adhesive and adhesive cell cultures from primary medullary thyroid tumor tissue. We found that the molecular markers of C cell such as Calcitonin and Ascl1 are predominantly enriched in the non-adhesive population (Kitajima et al., 2015). This is in line with the fact that one of most commonly distributed human MTC cell line TT is non-adhesive.