transfer-mammary-gland-forming-ability-between-mammary-basal

Transfer of Mammary Gland-forming Ability Between Mammary Basal Epithelial Cells and Mammary Luminal Cells via Extracellular Vesicles/Exosomes

Cells can communicate via exosomes, ~100-nm extracellular vesicles (EVs) that contain proteins, lipids, and nucleic acids. Non-adherent/mesenchymal ...

National Health Research Institutes

Developing biochemical and cell biological assay for screening biomolecules, evaluating their characteristics in biological processes, and determining their pharmacological effects represents a key technology in biomedical research. A PDMS-based integrated microfluidic platform was fabricated and tested for facilitating the labeling of ligand on the nanogram scale and sequential cell binding analysis in a manner that saves both time and reagents. Within this microfluidic platform, ligand labeling, cell immobolization, and optical analysis are performed in a miniaturized, continuous and semi-automated manner. This microfluidic device for ligand labeling and cell analysis is composed of two functional modules: (i) a circular reaction loop for fluorophore-labeling of the ligand and (ii) four parallel-oriented incubation chambers for immobilization of cells, binding of ligand to different cell populations, and optical evaluation of interactions between the labeled ligand and its cell targets. Epidermal growth factor (EGF) as the ligand and different cell lines with various levels of EGF receptor expression have been utilized to test the feasiblity of this microfluidic platform. When compared to studies with traditional Petri dish handling of cells and tissues, or even microwell analyses, experiments with the microfluidic platform described here are much less time consuming, conserve reagents, and are programmable, which makes these platforms a very promising new tool for biological studies.

A microfluidic platform for sequential ligand labeling and cell binding analysis.

Steroids are synthesized in adrenal glands and gonads under the control of pituitary peptides. These peptides bind to cell surface receptors to activate the cyclic AMP (cAMP) signaling pathway leading to an increase of steroidogenic gene expression. Exactly how cAMP activates steroidogenic gene expression is not clear, except for the knowledge that transcription factor SF-1 plays a key role. Investigating the factors participating in SF-1 action, we found that c-Jun and homeodomain-interacting protein kinase 3 (HIPK3) were required for basal and cAMP-stimulated expression of one major steroidogenic gene, CYP11A1. HIPK3 enhanced SF-1 activity, and c-Jun was required for the functional interaction of HIPK3 with SF-1. Furthermore, after cAMP stimulation, both c-Jun and Jun N-terminal kinase (JNK) were phosphorylated through HIPK3. These phosphorylations were important for SF-1 activity and CYP11A1 expression. Thus, we have defined HIPK3-mediated JNK activity and c-Jun phosphorylation as important events that increase SF-1 activity for CYP11A1 transcription in response to cAMP. This finding has linked three common factors, HIPK3, JNK, and c-Jun, to the cAMP signaling pathway leading to increased steroidogenic gene expression.

Cyclic AMP stimulates SF-1-dependent CYP11A1 expression through homeodomain-interacting protein kinase 3-mediated Jun N-terminal kinase and c-Jun phosphorylation.

Adenovirus vectors have a number of advantages for gene therapy. However, because of their lack of tumor tropism and their preference for liver infection following systemic administration, they cannot be used for systemic attack on metastatic disease. Many epithelial tumors (e.g., colon, lung, and breast) express carcinoembryonic antigen (CEA). To block the natural hepatic tropism of adenovirus and to "retarget" the virus to CEA-expressing tumors, we used a bispecific adapter protein (sCAR-MFE), which fuses the ectodomain of the coxsackie/adenovirus receptor (sCAR) with a single-chain anti-CEA antibody (MFE-23). sCAR-MFE untargets adenovirus-directed luciferase transgene expression in the liver by >90% following systemic vector administration. Moreover, sCAR-MFE can "retarget" adenovirus to CEA-positive epithelial tumor cells in cell culture, in s.c. tumor grafts, and in hepatic tumor grafts. The sCAR-MFE bispecific adapter should, therefore, be a powerful agent to retarget adenovirus vectors to epithelial tumor metastases.

Adenovirus tumor targeting and hepatic untargeting by a coxsackie/adenovirus receptor ectodomain anti-carcinoembryonic antigen bispecific adapter.

Unresectable hepatic colorectal cancer (CRC) metastases are a leading cause of cancer mortality. These tumors and other epithelial tumors often express both cyclooxygenase-2 (COX-2) and carcinoembryonic antigen (CEA). Because adenovirus (Ad) vectors infect the liver and lack tumor tropism, they cannot be used for systemic therapy of hepatic metastases. We used COX-2 transcriptional restriction, in combination with transductional Ad hepatic untargeting and tumor retargeting by a bispecific adapter, sCARhMFE, composed of sCAR [the coxsackie/Ad receptor (CAR) ectodomain] and MFE-23 (a single-chain anti-CEA antibody), to untarget liver after i.v. administration of Ad vectors expressing firefly luciferase and to retarget virus to hepatic colorectal tumor xenografts and non-small cell lung tumor xenografts. To improve both liver untargeting and tumor retargeting, we developed sCARfMFE, a trimerized sCARhMFE adapter. Trimerization greatly improves both untargeting of CAR-dependent Ad infection and CEA-dependent virus retargeting in culture and in vivo. Combining sCARfMFE bispecific adapter transductional liver untargeting and transductional tumor retargeting with COX-2 transcriptional tumor-restricted transgene expression increases systemically administered Ad therapeutic efficacy for hepatic CRC tumors, using herpes virus type 1 thymidine kinase (HSV1-tk) as a therapeutic gene in conjunction with the prodrug ganciclovir (GCV). Both transductional untargeting and COX-2 transcriptional restriction also reduce HSV1-tk/GCV hepatic toxicity. In addition, transductional sCARfMFE untargeting reduces the innate immune response to systemic Ad administration. Combined transductional liver Ad untargeting, transductional tumor retargeting, and transcriptional transgene restriction suggests a means to engineer practical, effective therapeutic agents for hepatic CRC metastases in particular, as well as hepatic metastases of other epithelial cancers.

Combined transductional untargeting/retargeting and transcriptional restriction enhances adenovirus gene targeting and therapy for hepatic colorectal cancer tumors.

Mesenchymal cells of the tumor-associated stroma are critical determinants of carcinoma cell behavior. We focus here on interactions of carcinoma cells with mesenchymal stem cells (MSC), which are recruited to the tumor stroma and, once present, are able to influence the phenotype of the carcinoma cells. We find that carcinoma cell-derived interleukin-1 (IL-1) induces prostaglandin E(2) (PGE(2)) secretion by MSCs. The resulting PGE(2) operates in an autocrine manner, cooperating with ongoing paracrine IL-1 signaling, to induce expression of a group of cytokines by the MSCs. The PGE(2) and cytokines then proceed to act in a paracrine fashion on the carcinoma cells to induce activation of β-catenin signaling and formation of cancer stem cells. These observations indicate that MSCs and derived cell types create a cancer stem cell niche to enable tumor progression via release of PGE(2) and cytokines.

Cancer-stimulated mesenchymal stem cells create a carcinoma stem cell niche via prostaglandin E2 signaling.

Prostaglandin E2 (PGE2 )-initiated signaling contributes to stem cell homeostasis and regeneration. However, it is unclear how PGE2 signaling controls cell stemness. This study identifies a previously unknown mechanism by which PGE2 /prostaglandin E receptor 4 (EP4 ) signaling regulates multiple signaling pathways (e.g., PI3K/Akt signaling, TGFβ signaling, Wnt signaling, EGFR signaling) which maintain the basal mammary stem cell phenotype. A shift of basal mammary epithelial stem cells (MaSCs) from a mesenchymal/stem cell state to a non-basal-MaSC state occurs in response to prostaglandin E receptor 4 (EP4 ) antagonism. EP4 antagonists elicit release of signaling components, by controlling their trafficking into extracellular vesicles/exosomes in a lipid raft/caveolae-dependent manner. Consequently, EP4 antagonism indirectly inactivates, through induced extracellular vesicle/exosome release, pathways required for mammary epithelial stem cell homeostasis, e.g. canonical/noncanonical Wnt, TGFβ and PI3K/Akt pathways. EP4 antagonism causes signaling receptors and signaling components to shift from non-lipid raft fractions to lipid raft fractions, and to then be released in EP4 antagonist-induced extracellular vesicles/exosomes, resulting in the loss of the stem cell state by mammary epithelial stem cells. In contrast, luminal mammary epithelial cells can acquire basal stem cell properties following ingestion of EP4 antagonist-induced stem cell extracellular vesicles/exosomes, and can then form mammary glands. These findings demonstrate that PGE2 /EP4 signaling controls homeostasis of mammary epithelial stem cells through regulating extracellular vesicle/exosome release. Reprogramming of mammary epithelial cells can result from EP4 -mediated stem cell property transfer by extracellular vesicles/exosomes containing caveolae-associated proteins, between mammary basal and luminal epithelial cells. Stem Cells 2017;35:425-444.

Hua-Jung Li

Institute of Cellular and System Medicine

National Health Research Institutes

Transfer of Mammary Gland-forming Ability Between Mammary Basal Epithelial Cells and Mammary Luminal Cells via Extracellular Vesicles/Exosomes