Search

Abstract Extracellular matrix (ECM) assembly/disassembly is a critical regulator for airway epithelial development and remodeling. Airway organoid is widely used in respiratory research, yet there is limited study to indicate the roles and mechanisms of ECM organization in epithelial growth and differentiation by using in vitro organoid system. Moreover, most of current Matrigel-based airway organoids are in basal-out orientation where accessing the apical surface is challenging. We present a human apical-out airway organoid using a biochemically defined hybrid hydrogel system. During human nasal epithelial progenitor cells (hNEPCs) differentiation, the gel gradually degrade, leading to the organoid apical surfaces facing outward. The expression and activity of ECM-degrading enzymes, matrix metalloproteinases (MMP7, MMP9, MMP10 and MMP13) increases during organoid differentiation, where inhibition of MMPs significantly suppresses the normal ciliation, resulting in increased goblet cell proportion. Moreover, a decrease of MMPs is found in goblet cell hyperplastic epithelium in inflammatory mucosa. This system reveals essential roles of epithelial-derived MMPs on epithelial cell fate determination, and provides an applicable platform enabling further study for ECM in regulating airway development in health and diseases.

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate gene expression post-transcriptionally by impeding mRNA translation or stability [...]

Many natural product biosynthetic gene clusters are found not to harbor a full set of necessary genes and must utilize enzymes encoded elsewhere (hidden) in the genome for biosynthesis. Here, the authors establish a global correlation network bridging the gap between lanthipeptide precursors and hidden proteases.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is characterized by heterogeneous inflammatory endotypes of unknown etiology. Invariant natural killer T (iNKT) cells are multifunctional innate T cells that exhibit Th1-, Th2-, and Th17-like characteristics. We investigated functional relationships between iNKT cells and inflammatory subtypes of CRSwNP. Eighty patients with CRSwNP and thirty-two control subjects were recruited in this study. Flow cytometry was used to analyze the frequencies and functions of iNKT cells and their subsets in peripheral blood mononuclear cells (PBMCs) and tissues. Polyp tissue homogenates were used to study the multifunctionality of iNKT cells. iNKT cells were significantly increased in polyps (0.41%) than in control mucosa (0.12%). iNKT cells were determined in the paucigranunlocytic (n=20), eosinophilic (n=22), neutrophilic (n=23), and mixed granulocytic (n=13) phenotypes of CRSwNP. The percentages of iNKT cells and HLA-DR+PD-1+ subsets were lower in eosinophilic or mixed granulocytic polyps than those of other phenotypes. iNKT cells and subsets were enriched in polyp tissues than in matched PBMCs. The evaluation of surface markers, transcription factors, and signature cytokines indicated that the frequencies of iNKT2 and iNKT17 subsets were significantly increased in eosinophilic and neutrophilic polyps, respectively, than in the paucigranulocytic group. Moreover, the production of type 2 (partially dependent on IL-7) and type 17 (partially dependent on IL-23) iNKT cells could be stimulated by eosinophilic and neutrophilic homogenates, respectively. Our study revealed that type 2 and type 17 iNKT cells were involved in eosinophilic and neutrophilic inflammation, respectively, in CRSwNP, while different inflammatory microenvironments could modulate the functions of iNKT cells, suggesting a role of iNKT cells in feedback mechanisms and local inflammation.

Approximately 75% of diagnosed breast cancer tumors are estrogen-receptor-positive tumors and are associated with a better prognosis due to response to hormonal therapies. However, around 40% of patients relapse after hormonal therapies. Genomic analysis of gene expression profiles in primary breast cancers and tamoxifen-resistant cell lines suggested the potential role of miR-489 in the regulation of estrogen signaling and development of tamoxifen resistance. Our in vitro analysis showed that loss of miR-489 expression promoted tamoxifen resistance, while overexpression of miR-489 in tamoxifen-resistant cells restored tamoxifen sensitivity. Mechanistically, we found that miR-489 is an estrogen-regulated miRNA that negatively regulates estrogen receptor signaling by using at least the following two mechanisms: (i) modulation of the ER phosphorylation status by inhibiting MAPK and AKT kinase activities; (ii) regulation of nuclear-to-cytosol translocation of estrogen receptor α (ERα) by decreasing p38 expression and consequently ER phosphorylation. In addition, miR-489 can break the positive feed-forward loop between the estrogen-Erα axis and p38 MAPK in breast cancer cells, which is necessary for its function as a transcription factor. Overall, our study unveiled the underlying molecular mechanism by which miR-489 regulates an estrogen signaling pathway through a negative feedback loop and uncovered its role in both the development of and overcoming of tamoxifen resistance in breast cancers.

MicroRNA 155 (miR-155) plays important roles in the regulation of the development and functions of a variety of immune cells. We previously revealed a vital role of miR-155 in regulating the function of dendritic cells (DCs) in breast cancer. miR-155 deficiency in DCs impaired their maturation, migration, cytokine production, and ability to activate T cells. In the current study, to exploit the therapeutic value of miR-155 for breast cancer, we examined the impact of overexpression of miR-155 on antitumor responses generated by DC vaccines. We boosted miR-155 expression in DCs by generating a miR-155 transgenic mouse strain (miR-155tg) or using lentivirus transduction. DCs overexpressing miR-155 exhibited enhanced functions in response to tumor antigens. Using miR-155 overexpressing DCs, we generated a DC vaccine and found that the vaccine resulted in enhanced antitumor immunity against established breast cancers in mice, demonstrated by increased effector T cells in the mice, suppressed tumor growth, and drastically reduced lung metastasis. Our current study suggests that in future DC vaccine development for breast cancer or other solid tumors, introducing forced miR155 overexpression in DCs via various approaches such as viral transduction or nanoparticle delivery, as well as including other adjuvant agents such as TLR ligands or immune stimulating cytokines, may unleash the full therapeutic potential of the DC vaccines.

HER2 is a tyrosine kinase receptor, which is overexpressed in about 30% of breast cancer patients. Its overexpression leads to mammary tumorigenesis and increased invasion and metastasis (Slamon et al., 1987). HER2 transgenic mouse (FVB/N-MMTVneu mouse) is a well-established model of mammary tumor in human (Fantozzi and Christofori, 2006). Although in vivo models are excellent for assessing the influence of various factors, especially microenvironment, on development of breast cancer, a convenient and less costly way to study the underlying molecular events is utilizing cells derived from the model under evaluation. In order to explore the molecular mechanism by which HOXB7 inhibits initiation, but promotes metastasis of breast tumors, we generated mouse breast cancer cell line from HER2 transgenic mouse (Liu et al., 2015). This protocol may be useful for the generation of breast cancer cell line from mice with other genetic backgrounds.

Depth image-based rendering (DIBR) is a method for generating new virtual images from known viewpoints. However, holes often appear in the rendered virtual images due to occlusion and inaccurate depth information. In this paper, we present a novel hole-filling algorithm to improve the image quality of DIBR. In the proposed method, depth information is added to the priority calculation function when determining the order of hole-filling. Then, the gradient information is used as auxiliary information when searching for the optimal matching block. Experimental results show that the proposed algorithm achieves better objective quality and also improves the subjective quality of the rendered images.

A tumorsphere is a solid, spherical formation developed from the proliferation of one cancer stem/progenitor cell. These tumorspheres (Figure 1a) are easily distinguishable from single or aggregated cells (Figure 1b) as the cells appear to become fused together and individual cells cannot be identified. Cells are grown in serum-free, non-adherent conditions in order to enrich the cancer stem/progenitor cell population as only cancer stem/progenitor cells can survive and proliferate in this environment. This assay can be used to estimate the percentage of cancer stem/progenitor cells present in a population of tumor cells. The size, which can vary from less than 50 micrometers to 250 micrometers, and number of tumorspheres formed can be used to characterize the cancer stem/progenitor cell population within a population of in vitro cultured cancer cells and within in vivo tumors (Lo et al., 2012; Liu et al., 2009). While several cell lines can be used for tumorsphere formation assay (e.g. primary mammary tumor cells from Her2/neu-transgenic mice, MCF7, BT474 and HCC1954), some cell lines may not form typical tumorsphere structures and may be difficult to count or classify definitively as tumorspheres.

The isolation of cancer epithelial cells from mouse mammary tumor is accomplished by digestion of the solid tumor. Red blood cells and other contaminates are removed using several washing techniques such that primary epithelial cells can further enriched. This procedure yields primary tumor cells that can be used for in vitro tissue culture, fluorescence-activated cell sorting (FACS) and a wide variety of other experiments (Lo et al., 2012).

Interactions with cofactors regulate transcriptional activity and also help HOX proteins to achieve the specificity required for transcriptional regulation of target genes. In this study, we describe a novel protein/protein interaction of HOXB7 with poly (ADP-ribose) polymerase-1 (PARP-1) that involves the homeodomain of HOXB7 and the first zinc finger domain of PARP-1. Upon binding to PARP-1, HOXB7 undergoes poly(ADP-ribosyl)altion resulting in a reduction of its transcriptional activity. Since aspartic acid and glutamic acid residues are acceptors of the ADP ribose moiety transferred by PARP-1, deletion of the evolutionarily conserved C-terminal Glu-rich tail of HOXB7 dramatically attenuates ADP-ribosylation of HOXB7 by PARP-1. Further, a mutant of HOXB7 without the Glu-rich tail loses the ability to be negatively regulated by PARP-1 and becomes transcriptionally more active in luciferase reporter assays. Since the homeodomain is highly conserved among HOX proteins, five other HOX proteins were tested. All six showed interaction with, and were poly(ADP-ribosyl)ated by PARP-1. However, among them, this modification altered the DNA binding activity of only HOXA7 and HOXB7. In summary, this study identifies a new interacting partner of HOX proteins. More importantly, this study reveals a novel mechanism whereby polyADP-ribosylation regulates transcriptional activities of HOX proteins such as HOXB7 and HOXA7.

Nasopharyngeal carcinoma (NPC) is a common malignancy of the head and neck that arises from the nasopharynx epithelium and is highly invasive. Cyclin-dependent kinase inhibitor 3 (CDKN3) belongs to the dualspecificity protein phosphatase family, which plays a key role in regulating cell division. Abnormal expression of CDKN3 has been found in numerous types of cancer. In the current study, we explored the possible role of CDKN3 in cell proliferation, ability to invade, and radiosensitivity in NPC cells. We reported that CDKN3 was upregulated and p27 was downregulated in NPC tissues and is associated with a worse prognosis for patients. In addition, downregulation of CDKN3 and upregulation of p27 decreased cell proliferation, induced cell cycle arrest, increased apoptosis, decreased cell invasion, and enhanced radiosensitivity. Silencing of p27 significantly inhibited the effects of the knockdown of CDKN3. Moreover, downregulation of CDKN3 and upregulation of p27 inhibited the increase in tumor volume and weight in implanted tumors, decreased the phosphorylation of Akt, and increased the expression of cleaved caspase 3 in tumors. CDKN3 expression was also inversely correlated with p27 expression in NPC patients. Knockdown of CDKN3 increased p27 expression. Silencing of p27 markedly inhibited the effects of CDKN3 on cell proliferation, cell cycle progression, apoptosis, invasion, and radiosensitivity. These results demonstrate that upregulation of p27 is involved in the knockdown of CDKN3-induced decrease in cell proliferation, increase in cell cycle arrest and apoptosis, decrease in invasion, and increase in radiosensitivity. The results demonstrate that the CDKN3/p27 axis may be a novel target in the treatment of NPC. [ABSTRACT FROM AUTHOR]