Integrins are required for synchronous ommatidial rotation in the Drosophila eye linking planar cell polarity signalling to the extracellular matrix

Interommatidial cells build a tensile collagen network during Drosophila retinal morphogenesis

Drosophila compound eye morphogenesis transforms a simple epithelium into an approximate hollow hemisphere comprised of ∼700 ommatidia, packed as tapering hexagonal prisms between a rigid external array of cuticular lenses and a parallel, rigid internal floor, the fenestrated membrane (FM). Critical to vision, photosensory rhabdomeres are sprung between these two surfaces, grading their length and shape accurately across the eye and aligning them to the optical axis. Using fluorescently tagged collagen and laminin, we show that that the FM assembles sequentially, emerging in the larval eye disc in the wake of the morphogenetic furrow as the original collagen-containing basement membrane (BM) separates from the epithelial floor and is replaced by a new, laminin-rich BM, which advances around axon bundles of newly differentiated photoreceptors as they exit the retina, forming fenestrae in this new, laminin-rich BM. In mid-pupal development, the interommatidial cells (IOCs) autonomously deposit collagen at fenestrae, forming rigid, tension-resisting grommets. In turn, stress fibers assemble in the IOC basal endfeet, where they contact grommets at anchorages mediated by integrin linked kinase (ILK). The hexagonal network of IOC endfeet tiling the retinal floor couples nearest-neighbor grommets into a supracellular tri-axial tension network. Late in pupal development, IOC stress fiber contraction folds pliable BM into a hexagonal grid of collagen-stiffened ridges, concomitantly decreasing the area of convex FM and applying essential morphogenetic longitudinal tension to rapidly growing rhabdomeres. Together, our results reveal an orderly program of sequential assembly and activation of a supramolecular tensile network that governs Drosophila retinal morphogenesis.

Function and prognostic value of basement membrane -related genes in lung adenocarcinoma

Background: Lung adenocarcinoma (LUAD) has become a common cause of cancer-related death. Many studies have shown that the basement membrane (BM) is associated with the development of cancer. However, BM-related gene expression and its relationship to LUAD prognosis remains unclear. Methods: BM-related genes from previous studies were used. Clinical and mRNA expression information were obtained from TCGA database. Cox, minimum absolute contraction, and selection operator regression were applied to analyze the selected genes affecting LUAD prognosis. A prognostic-risk model was then established. Furthermore, this study applied Kaplan-Meier analysis to assess the outcomes of high- and low-risk groups, then explored their differences in drug sensitivity. The DSigDB database was used to screen for therapeutic small-molecule drugs. Results: Fourteen prognostic models based on BM-related genes were successfully constructed and validated in patients with LUAD. We also found that independence was a prognostic factor in all 14 BM-based models. Functional analysis showed that the enrichment of BM-related genes mainly originated from signaling pathways related to cancer. The BM-based model also suggested that immune cell infiltration is associated with checkpoints. The low-risk patients may benefit from cyclopamine and docetaxel treatments. Conclusion: This study identified a reliable biomarker to predict survival in patients with LUAD and offered new insights into the function of BM-related genes in LUAD.

Notch-dependent Abl signaling regulates cell motility during ommatidial rotation in Drosophila

A collective cell motility event that occurs during Drosophila eye development, ommatidial rotation (OR), serves as a paradigm for signaling-pathway-regulated directed movement of cell clusters. OR is instructed by the EGFR and Notch pathways and Frizzled/planar cell polarity (Fz/PCP) signaling, all of which are associated with photoreceptor R3 and R4 specification. Here, we show that Abl kinase negatively regulates OR through its activity in the R3/R4 pair. Abl is localized to apical junctional regions in R4, but not in R3, during OR, and this apical localization requires Notch signaling. We demonstrate that Abl and Notch interact genetically during OR, and Abl co-immunoprecipitates in complexes with Notch in eye discs. Perturbations of Abl interfere with adherens junctional organization of ommatidial preclusters, which mediate the OR process. Together, our data suggest that Abl kinase acts directly downstream of Notch in R4 to fine-tune OR via its effect on adherens junctions.

Wnt-frizzled planar cell polarity signaling in the regulation of cell motility

The molecular complexes underlying planar cell polarity (PCP) were first identified in Drosophila through analysis of mutant phenotypes in the adult cuticle and the orientation of associated polarized protrusions such as wing hairs and sensory bristles. The same molecules are conserved in vertebrates and are required for the localization of polarized protrusions such as primary or sensory cilia and the orientation of hair follicles. Not only is PCP signaling required to align cellular structures across a tissue, it is also required to coordinate movement during embryonic development and adult homeostasis. PCP signaling allows cells to interpret positional cues within a tissue to move in the appropriate direction and to coordinate this movement with their neighbors. In this review we outline the molecular basis of the core Wnt-Frizzled/PCP pathway, and describe how this signaling orchestrates collective motility in Drosophila and vertebrates. Here we cover the paradigms of ommatidial rotation and border cell migration in Drosophila, and convergent extension in vertebrates. The downstream cell biological processes that underlie polarized motility include cytoskeletal reorganization, and adherens junctional and extracellular matrix remodeling. We discuss the contributions of these processes in the respective cell motility contexts. Finally, we address examples of individual cell motility guided by PCP factors during nervous system development and in cancer disease contexts.

A Pan-Cancer Analysis of the Oncogenic Role of Integrin Beta4 (ITGB4) in Human Tumors

Background

Integrin beta4 (ITGB4) is a transmembrane receptor that plays a key role in tumorigenesis and tumor development. However, there are no pan-cancer analyses of ITGB4.

Methods

This study demonstrates the first potential oncogenic roles of ITGB4 across 33 tumors based on the dataset of the Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO).

Results

ITGB4 is highly expressed in many cancers, and distinct correlations exist between ITGB4 expression and the prognosis of tumor patients. We also found that the methylation and genetic alteration level of ITGB4 was associated with some cancer prognosis. Furthermore, we found a reduced phosphorylation of ITGB4 at S1457 in several tumors, such as breast and ovarian cancers. Finally, ITGB4 expression was correlated with cancer-associated fibroblasts in liver hepatocellular carcinoma and prostate adenocarcinoma, and the infiltration level of NK cells and neutrophils was observed in other cancers, such as breast invasive carcinoma and lung adenocarcinoma. Moreover, RNA metabolism and protein processing-associated functions are involved in the functional mechanism of ITGB4.

Conclusion

Our first pan-cancer study may offer a relatively comprehensive understanding of the oncogenic roles of ITGB4 across different tumors.

Tissue fluidity mediated by adherens junction dynamics promotes planar cell polarity-driven ommatidial rotation

The phenomenon of tissue fluidity-cells' ability to rearrange relative to each other in confluent tissues-has been linked to several morphogenetic processes and diseases, yet few molecular regulators of tissue fluidity are known. Ommatidial rotation (OR), directed by planar cell polarity signaling, occurs during Drosophila eye morphogenesis and shares many features with polarized cellular migration in vertebrates. We utilize in vivo live imaging analysis tools to quantify dynamic cellular morphologies during OR, revealing that OR is driven autonomously by ommatidial cell clusters rotating in successive pulses within a permissive substrate. Through analysis of a rotation-specific nemo mutant, we demonstrate that precise regulation of junctional E-cadherin levels is critical for modulating the mechanical properties of the tissue to allow rotation to progress. Our study defines Nemo as a molecular tool to induce a transition from solid-like tissues to more viscoelastic tissues broadening our molecular understanding of tissue fluidity.

Effects of Xuefu Zhuyu Decoction on Cell Migration and Ocular Tumor Invasion inDrosophila

Xuefu Zhuyu Decoction (XFZYD), a Traditional Chinese Medicine (TCM) decoction mainly for treating blood stasis syndrome, has been widely investigated and applied in clinic and in laboratory. XFZYD contains 11 herbs and has been identified to promoting blood circulation to remove blood stasis for cardiovascular disease. Meanwhile, blood stasis is directly related to malignant tumor according to TCM basic theory. However, the effects of XFZYD on tumor metastasis and the underlying mechanisms are still largely unknown. Here, we employed well-establishedDrosophilacell migration and tumor invasion models to explore whether XFZYD has the anticancer activity on tumor metastasisin vivo. Our work has demonstrated that XFZYD could suppress cell migration and tumor invasion at the moderate concentrations. In addition, XFZYD altered the expression of MMP1,β-integrin, and E-cadherin to impede cell migration. Moreover, XFZYD inhibited ocular tumor invasion presumably by reducing the activity of Notch signaling. Together, these evidences reveal a positive role of XFZYD in suppressing cell migration and tumor metastasis, providing the potential drug targets and key clues for cancer clinical treatment strategies.

Inhibition of Rho-associated protein kinase improves the survival of human induced pluripotent stem cell-derived cardiomyocytes after dissociation

Heart disease remains the leading cause of morbidity and mortality worldwide. Induced pluripotent stem cells (iPSCs) have the ability to differentiate into cardiomyocytes (CMs), rendering this cell type to be a promising pre-cursor of cardiomyocytes for cell-based cardiac regeneration. Obtaining CMs with a high yield and purity coupled with improved subsequent survival could prove to be invaluable for the future cell replacement therapeutic strategies. Rho-associated protein kinase (ROCK) is involved in a wide range of fundamental cellular functions and serves significant roles in cardiac physiology. In the present study, human (h)iPSC-CMs were generated from iPSCs by including glycogen synthase kinase 3β and Wnt inhibitors in the basal culture media. The possible effect of Y27632, a ROCK inhibitor, on hiPSC-CMs was then investigated. hiPSC-CMs of high purity were harvested with >96% of cells expressing cardiac troponin T. Additionally, treatment with 10 µM Y27632 significantly improved the viability of dissociated hiPSC-CMs. The effects of ROCK inhibitors Y27632 and fasudil, on the proliferation and apoptosis of hiPSC-CMs were also examined. Treatment with ROCK inhibitors markedly enhanced hiPSC-CM proliferation, by up to 2.5-fold, whilst Y27632 treatment reduced apoptosis in hiPSC-derived CMs under serum starvation and suspension by suppressing the expression of caspase-3. Taken together, data from the present study indicated that ROCK kinase inhibitors effectively improved the cultural system of hiPSC-derived CMs.