癌症生物学

The initiation and progression of prostate cancer (PCa) are associated with aging. In the history of age-related PCa research, mice have become a more popular animal model option than any other species due to their short lifespan and rapid reproduction. However, PCa in mice is usually induced at a relatively young age, while it spontaneously develops in humans at an older age. Thus, it is essential to develop a method by which the PCa initiation and progression timeline can be strictly controlled to mimic human physiological conditions. One milestone in this field was the identification of the prostate-specific transcription factor, Probasin (Pb), which allowed for the prostate-specific expression of genes knocked into the mice's genome. Another milestone is the establishment of the preclinical mouse model with Pten conditionally knocked out in the prostate tissue, which closely mimics the formation and growth of human PCa. Hereby, we present the prostate-specific temporally and spatially controlled Pten knockout PCa mouse model that can be induced using an adenovirus-based Cre-LoxP system. The Cre recombinase (Cre) is inserted into an adenovirus vector. Unlike Pb-Cre knock-in models (which are spatially but not temporally controlled), the expression of Cre is activated to knock out Pten from the mice's prostate epithelial cells once injected. The viral delivery procedures strictly control the location and time of Pten knockout. This novel approach provides a powerful age-related murine model for PCa, emphasizing the effect of aging on prostate carcinogenesis.

Endometrial cancer (EC) is the leading cause of gynecologic cancer morbidity and mortality in the U.S. Despite advancements in cancer research, EC death rates are increasing, particularly high-grade endometrial cancers. The development of three-dimensional (3D) patient-derived organoid (PDO) models for EC is crucial, as they provide a more accurate representation of the biological and genetic complexity of a patient’s tumor compared to traditional 2D cell lines. Here, we describe a protocol for cultivating PDO models from normal endometrium and EC across different EC subtypes. These EC PDO models can be expanded across multiple passages and facilitate the exploration of tumor behavior and drug responses, thereby advancing our understanding of the disease and potentially leading to more effective and individualized novel therapeutic strategies.

Bone metastasis is a frequent and lethal complication of many cancer types (i.e., prostate cancer, breast cancer, and multiple myeloma), and a cure for bone metastasis remains elusive. To recapitulate the process of bone metastasis and understand how cancer cells metastasize to bone, intracardiac injection and intracaudal arterial animal models were developed. The intratibial injection animal model was established to investigate the communication between cancer cells and the bone microenvironment and to mimic the setting of prostate cancer patients with bone metastasis. Given that detailed protocols of intratibial injection and its quantitative analysis are still insufficient, in this protocol, we provide hands-on procedures for how to prepare cells, perform the tibial injection, monitor tibial tumor growth, and quantitatively evaluate the tibial tumors in pathological samples. This manuscript provides a ready-to-use experimental protocol for investigating cancer cell behaviors in bone and developing novel therapeutic strategies for bone metastatic cancer patients.

Characterization of key regulators in vein development will advance our understanding of mechanisms underlying venous anomalies and provide therapeutic targets for the treatment of vascular malformations. Here, we provide a detailed protocol for the generation of genetically engineered mouse models targeting the Tek gene for the analysis of vein formation and vein-associated vascular diseases at the embryonic and postnatal stages. It includes steps involved in the whole-mount processing of mouse skin, mesentery, and retina for the examination of vascular malformation during embryonic and postnatal development.

The mammary gland is a highly dynamic tissue that changes throughout reproductive life, including growth during puberty and repetitive cycles of pregnancy and involution. Mammary gland tumors represent the most common cancer diagnosed in women worldwide. Studying the regulatory mechanisms of mammary gland development is essential for understanding how dysregulation can lead to breast cancer initiation and progression. Three-dimensional (3D) mammary organoids offer many exciting possibilities for the study of tissue development and breast cancer. In the present protocol derived from Sumbal et al., we describe a straightforward 3D organoid system for the study of lactation and involution ex vivo. We use primary and passaged mouse mammary organoids stimulated with fibroblast growth factor 2 (FGF2) and prolactin to model the three cycles of mouse mammary gland lactation and involution processes. This 3D organoid model represents a valuable tool to study late postnatal mammary gland development and breast cancer, in particular postpartum-associated breast cancer.

Graphic abstract:

Mammary gland organoid isolation and culture procedures

Tumor xenograft models developed by transplanting human tissues or cells into immune-deficient mice are widely used to study human cancer response to drug candidates. However, immune-deficient mice are unfit for investigating the effect of immunotherapeutic agents on the host immune response to cancer (Morgan, 2012). Here, we describe the preparation of an orthotopic, syngeneic model of lung adenocarcinoma (LUAD), a subtype of non-small cell lung cancer (NSCLC), to study the antitumor effect of chemo and immunotherapeutic agents in an immune-competent animal. The tumor model is developed by implanting 344SQ LUAD cells derived from the metastases of Kras^G12D; p53^R172HΔG genetically engineered mouse model into the left lung of a syngeneic host (Sv/129). The 344SQ LUAD model offers several advantages over other models: 1) The immune-competent host allows for the assessment of the biologic effects of immune-modulating agents; 2) The pathophysiological features of the human disease are preserved due to the orthotopic approach; 3) Predisposition of the tumor to metastasize facilitates the study of therapeutic effects on primary tumor as well as the metastases (Chen et al., 2014). Furthermore, we also describe a treatment strategy based on Poly(2-oxazoline) micelles that has been shown to be effective in this difficult-to-treat tumor model (Vinod et al., 2020b).