Significance of Cancer-Associated Fibroblasts in the Interactions of Cancer Cells with the Tumor Microenvironment of Heterogeneous Tumor Tissue.

The tumor microenvironment (TME) plays a key role in cancer development and progression, as well as contributes to the therapeutic resistance and metastasis of cancer cells. The TME is heterogeneous and consists of multiple cell types, including cancer-associated fibroblasts (CAFs), endothelial cells, and immune cells, as well as various extracellular components. Recent studies have revealed cross talk between cancer cells and CAFs as well as between CAFs and other TME cells, including immune cells.

Pixel-Level Clustering of Hematoxylin-Eosin-Stained Sections of Mouse and Human Biliary Tract Cancer.

We previously established mouse models of biliary tract cancer (BTC) based on the injection of cells with biliary epithelial stem cell properties derived from KRAS(G12V)-expressing organoids into syngeneic mice. The resulting mouse tumors appeared to recapitulate the pathological features of human BTC. Here we analyzed images of hematoxylin and eosin (H&E) staining for both the mouse tumor tissue and human cholangiocarcinoma tissue by pixel-level clustering with machine learning.

Mutation of (Encoding SHP-2) Promotes MEK Activation and Malignant Progression in Neurofibromin-Deficient Cells in a Manner Sensitive to Mutation.

Germline mutations of cause neurofibromatosis type 1 () through the activation of the signaling pathway, and some patients develop malignant peripheral nerve sheath tumors (MPNSTs). Here, we established subclones of the human -MPNST cell line sNF96.2 that manifest increased tumorigenic activity and increased phosphorylation of the protein kinases MEK and Akt relative to the parental cells.

TGFβ Signaling Activated by Cancer-Associated Fibroblasts Determines the Histological Signature of Lung Adenocarcinoma.

Invasive lung adenocarcinoma (LADC) can be classified histologically as lepidic, acinar, papillary, micropapillary, or solid. Most LADC tumors manifest several of these histological subtypes, with heterogeneity being related to therapeutic resistance. We report here that in immunodeficient mice, human LADC cells form tumors with distinct histological features, MUC5AC-expressing solid-type or cytokeratin 7 (CK7)-expressing acinar-type tumors, depending on the site of development, and that a solid-to-acinar transition (SAT) could be induced by the tumor microenvironment.

Lung Adenocarcinoma Mouse Models Based on Orthotopic Transplantation of Syngeneic Tumor-Initiating Cells Expressing EpCAM, SCA-1, and Ly6d.

Somatic mutations in and as well as chromosome rearrangements affecting , , and have been identified in human lung adenocarcinoma (LUAD). We here developed organoid-based orthotopic and syngeneic mouse models for studies of the pathogenesis and treatment of LUAD. We isolated EpCAM-positive epithelial cells from mouse lungs and cultured them as organoids to maintain epithelial stem cell properties.

Oncogenic KRAS-expressing organoids with biliary epithelial stem cell properties give rise to biliary tract cancer in mice.

Biliary tract cancer (BTC) arises from biliary epithelial cells (BECs) and includes intrahepatic cholangiocarcinoma (IHCC), gallbladder cancer (GC), and extrahepatic cholangiocarcinoma (EHCC). Although frequent KRAS mutations and epigenetic changes at the INK4A/ARF locus have been identified, the molecular pathogenesis of BTC is unclear and the development of corresponding anticancer agents remains inadequate. We isolated epithelial cell adhesion molecule (EpCAM)-positive BECs from the mouse intrahepatic bile duct, gallbladder, and extrahepatic bile duct, and established organoids derived from these cells.

Targeting of cancer stem cells by differentiation therapy.

Chemoresistance is a hallmark of cancer stem cells (CSCs). To develop novel therapeutic strategies that target CSCs, we established osteosarcoma-initiating (OSi) cells by introducing the c-Myc gene into bone marrow stromal cells derived from Ink4a/Arf KO mice. These OSi cells include bipotent committed cells (similar to osteochondral progenitor cells) with a high tumorigenic activity as well as tripotent cells (similar to mesenchymal stem cells) of low tumorigenicity.

Molecular and cellular mechanisms underlying brain metastasis of breast cancer.

Metastasis of cancer cells to the brain occurs frequently in patients with certain subtypes of breast cancer. In particular, patients with HER2-positive or triple-negative breast cancer are at high risk for the development of brain metastases. Despite recent advances in the treatment of primary breast tumors, the prognosis of breast cancer patients with brain metastases remains poor.

HER2 Heterogeneity Is Associated with Poor Survival in HER2-Positive Breast Cancer.

Intratumoral human epidermal growth factor receptor 2 (HER2) heterogeneity has been reported in 16⁻36% of HER2-positive breast cancer and its clinical impact is under discussion. We examined the biological effects of HER2-heterogeneity on mouse models and analyzed metastatic brains by RNA sequence analysis. A metastatic mouse model was developed using 231-Luc (triple negative cells) and 2 HER2-positive cell lines, namely, HER2-60 and HER2-90 which showed heterogeneous and monotonous HER2 expressions, respectively.

Tranilast inhibits the expression of genes related to epithelial-mesenchymal transition and angiogenesis in neurofibromin-deficient cells.

Neurofibromatosis type 1 (NF1) is caused by germline mutations in the NF1 gene and is characterized by café au lait spots and benign tumours known as neurofibromas. NF1 encodes the tumour suppressor protein neurofibromin, which negatively regulates the small GTPase Ras, with the constitutive activation of Ras signalling resulting from NF1 mutations being thought to underlie neurofibroma development. We previously showed that knockdown of neurofibromin triggers epithelial-mesenchymal transition (EMT) signalling and that such signalling is activated in NF1-associated neurofibromas.

Periostin antisense oligonucleotide suppresses bleomycin-induced formation of a lung premetastatic niche for melanoma.

Metastasis is the leading cause of cancer death. A tumor-supportive microenvironment, or premetastatic niche, at potential secondary tumor sites plays an important role in metastasis, especially in tumor cell colonization. Although a fibrotic milieu is known to promote tumorigenesis and metastasis, the underlying molecular contributors to this effect have remained unclear.

Organotypic brain explant culture as a drug evaluation system for malignant brain tumors.

Therapeutic options for malignant brain tumors are limited, with new drugs being continuously evaluated. Organotypic brain slice culture has been adopted for neuroscience studies as a system that preserves brain architecture, cellular function, and the vascular network. However, the suitability of brain explants for anticancer drug evaluation has been unclear.

Prospects for new lung cancer treatments that target EMT signaling.

Lung cancer is the most common cancer worldwide. Treatment options for lung cancer include surgery, radiation therapy, chemotherapy, molecularly targeted therapy including epidermal growth factor receptor or anaplastic lymphoma kinase inhibitors, and immunotherapy. These treatments can be administered alone or in combination.

RNA Sequencing Analysis Reveals Interactions between Breast Cancer or Melanoma Cells and the Tissue Microenvironment during Brain Metastasis.

Metastasis is the main cause of treatment failure and death in cancer patients. Metastasis of tumor cells to the brain occurs frequently in individuals with breast cancer, non-small cell lung cancer, or melanoma. Despite recent advances in our understanding of the causes and in the treatment of primary tumors, the biological and molecular mechanisms underlying the metastasis of cancer cells to the brain have remained unclear.

Development of mouse models of malignant phyllodes tumors by transplantation of syngeneic mammary gland cells expressing mutant H-Ras.

Phyllodes tumors (PTs) are rare fibroepithelial tumors of the breast with epithelial and stromal components, and surgical resection is the standard and only available treatment for malignant PTs. To provide a better understanding of these tumors, we developed mouse models that recapitulate the pathological and clinical properties of human malignant PTs. Mouse undifferentiated mammary gland cells were infected with a retrovirus encoding the human oncoprotein H-Ras , and the infected cells were transplanted orthotopically into the mammary fat pads of syngeneic mice.

Concise Review: Stem Cells and Epithelial-Mesenchymal Transition in Cancer: Biological Implications and Therapeutic Targets.

Cancer stem cells (CSCs) constitute a small subpopulation of cancer cells with stem-like properties that are able to self-renew, generate differentiated daughter cells, and give rise to heterogeneous tumor tissue. Tumor heterogeneity is a hallmark of cancer and underlies resistance to anticancer therapies and disease progression. The epithelial-mesenchymal transition (EMT) is a reversible phenomenon that is mediated by EMT-inducing transcription factors (EMT-TFs) and plays an important role in normal organ development, wound healing, and the invasiveness of cancer cells.

Generation of heterozygous fibrillin-1 mutant cloned pigs from genome-edited foetal fibroblasts.

Marfan syndrome (MFS) is an autosomal dominant genetic disease caused by abnormal formation of the extracellular matrix with an incidence of 1 in 3, 000 to 5, 000. Patients with Marfan syndrome experience poor quality of life caused by skeletal disorders such as scoliosis, and they are at high risk of sudden death from cardiovascular impairment. Suitable animal models of MFS are essential for conquering this intractable disease.

The use of next-generation sequencing in molecular diagnosis of neurofibromatosis type 1: a validation study.

Aims: We assessed the validity of a next-generation sequencing protocol using in-solution hybridization-based enrichment to identify NF1 mutations for the diagnosis of 86 patients with a prototypic genetic syndrome, neurofibromatosis type 1. In addition, other causative genes for classic genetic syndromes were set as the target genes for coverage analysis.

Results: The protocol identified 30 nonsense, 19 frameshift, and 8 splice-site mutations, together with 10 nucleotide substitutions that were previously reported to be pathogenic.

Expression of CD24 is associated with HER2 expression and supports HER2-Akt signaling in HER2-positive breast cancer cells.

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer is treated with HER2-targeted agents, such as trastuzumab and lapatinib, that suppress signaling by phosphatidylinositol 3-kinase (PI3K)-Akt and MAPK pathways. However, resistance to HER2-targeted therapy remains a major clinical problem. Overexpression of CD24 has been detected in many cancers and is associated with a poor prognosis in women with breast cancer.

Lysyl oxidase is induced by cell density-mediated cell cycle suppression via RB-E2F1-HIF-1α axis.

Remodeling of the matrix surrounding tumor cells plays a crucial role in the development and maintenance of cancer. Lysyl oxidase (LOX), a matrix remodeling factor, is induced by HIF-1α under hypoxic conditions and associated with tumor growth and metastasis. Here, we report that high cell density induces HIF-1α expression under normoxic condition, resulting in the promotion of LOX expression.

LATS1/WARTS phosphorylates MYPT1 to counteract PLK1 and regulate mammalian mitotic progression.

In the mitotic exit network of budding yeast, Dbf2 kinase phosphorylates and regulates Cdc14 phosphatase. In contrast, no phosphatase substrates of LATS1/WARTS kinase, the mammalian equivalent of Dbf2, has been reported. To address this discrepancy, we performed phosphoproteomic screening using LATS1 kinase.

Induction of ZEB proteins by inactivation of RB protein is key determinant of mesenchymal phenotype of breast cancer.

We previously showed that depletion of the retinoblastoma protein (RB) induces down-regulation of the adhesion molecule E-cadherin and thereby triggers the epithelial-mesenchymal transition. To further characterize the effect of RB inactivation on the phenotype of cancer cells, we have now examined RB expression in human breast cancer cell lines and clinical specimens. We found that RB-inactive cells exhibit a mesenchymal-like morphology and are highly invasive.

Loss of p16 expression is associated with the stem cell characteristics of surface markers and therapeutic resistance in estrogen receptor-negative breast cancer.

Triple-negative breast cancer [TNBC, which is negative for the estrogen receptor (ER), progesterone receptor, and human epidermal growth factor receptor 2] is a high-risk form of the disease without a specific therapy. DNA microarray and immunohistochemical analyses have shown that most TNBCs fall within the basal-like histological subset of breast cancers, which frequently exhibit inactivation of the retinoblastoma tumor suppressor (Rb) and upregulation of the cyclin-dependent kinase inhibitor p16(INK4a) (p16). However, downregulation of p16 expression has been observed in some basal-like breast cancer cell lines, suggesting that such cells can be divided into two groups according to Rb and p16 status.

Decreased expression of neurofibromin contributes to epithelial-mesenchymal transition in neurofibromatosis type 1.

Plexiform and/or dermal neurofibromas are nerve sheath tumors of the peripheral nervous system that are usually present in individuals with neurofibromatosis type 1 (NF1). Neurofibromas arise from Schwann cells with biallelic inactivation of NF1, the gene that encodes neurofibromin. This protein is responsible for regulation of the Ras-mediated pathway, which has been shown to play a crucial role in epithelial-to-mesenchymal transition (EMT).