A new approach to measure forces at junction vertices in an epithelium

The mechanical properties of cell-cell junctions are critical for the stability of an epithelium. Cell-cell junction ablation experiments are classically used as a readout for junctional mechanics. However, without the knowledge of the viscoelastic properties of the microenvironment of the ablated junction, tensile junctional forces cannot be measured. Here we combine laser ablation with intracellular microrheology and develop a model to measure tensile forces exerted on cell-cell junctions. We show that the overexpression of the proto-oncogene atypical Protein Kinase C iota (aPKCi) in a single cell within a normal epithelium induces a gradient of junctional tension with neighbouring cells. Our method allows us to demonstrate that junctions contacting the aPKCi-overexpressing cell display a mechanical asymmetry which correlates with the levels of E-cadherin and P-MLC2. Measuring intracellular viscoelasticity is crucial for accurate measurements of cell-cell junction mechanics in the context of development or cancer research.

Anticancer Mechanism of Withania Somnifera and Its Bioactive Compounds : A Short Review Along with Computational Molecular Docking Study

<p>Withania somnifera, known as Aswogondha in Bangladesh and some part of India, is a shrub of Solanceae family. Parts of this plant is used as alternative medicine in this region to cure diseases from bronchitis to insomnia. Although such use of the plant is not supported by clinical research, recent studies have found anticancer activity of some proteins derived from w. somnifera. The purpose of this study is to summarize the anticancer activity of medicinal plant Withania somnifera and its bioactive compounds as well as to predict the interaction between phytochemicals (Withanolide, Withaferin-A) and macromolecules that are responsible for cancer cell proliferation. Studies suggested that Withanolide and Withaferin-A from W. somnifera can be used as a cancer chemotherapeutic agent for cancerous cell lines in mice models through modulating various signaling pathway including inhibition, autophagy, apoptosis, radiopreventive pathway and reactive oxygen species pathway. Molecular docking of Withanolide and Withaferin-A against 9 types of vital protein mediators concluded that 3A8X (Protein kinase C iota type) and 1A9U (MAP KINASE P38) are the most active receptor for binding and interacting with Withanolide and Withaferin-A for the prevention and treatment of cancer. On the basis of this review and docking study, it can be concluded that Withania somnifera as well as its derivatives Withanolide and Withaferin-A may be considered as a promising anticancer agent. </p>

Anticancer Mechanism of Withania Somnifera and Its Bioactive Compounds : A Short Review Along with Computational Molecular Docking Study

<p>Withania somnifera, known as Aswogondha in Bangladesh and some part of India, is a shrub of Solanceae family. Parts of this plant is used as alternative medicine in this region to cure diseases from bronchitis to insomnia. Although such use of the plant is not supported by clinical research, recent studies have found anticancer activity of some proteins derived from w. somnifera. The purpose of this study is to summarize the anticancer activity of medicinal plant Withania somnifera and its bioactive compounds as well as to predict the interaction between phytochemicals (Withanolide, Withaferin-A) and macromolecules that are responsible for cancer cell proliferation. Studies suggested that Withanolide and Withaferin-A from W. somnifera can be used as a cancer chemotherapeutic agent for cancerous cell lines in mice models through modulating various signaling pathway including inhibition, autophagy, apoptosis, radiopreventive pathway and reactive oxygen species pathway. Molecular docking of Withanolide and Withaferin-A against 9 types of vital protein mediators concluded that 3A8X (Protein kinase C iota type) and 1A9U (MAP KINASE P38) are the most active receptor for binding and interacting with Withanolide and Withaferin-A for the prevention and treatment of cancer. On the basis of this review and docking study, it can be concluded that Withania somnifera as well as its derivatives Withanolide and Withaferin-A may be considered as a promising anticancer agent. </p>

aPKC drives cilia-independent Hedgehog signaling to maintain basal cell carcinoma growth

Primary cilia loss is a common feature of advanced cancers. While primary cilia are necessary to initiate Hedgehog (HH)-driven cancers, how HH pathway activity is maintained in advanced cancers devoid of primary cilia is unclear. Here, we find that HH-driven basal cell carcinoma (BCC) accumulate mutations in the Alström and Usher syndrome genes in advanced and SMO inhibitorresistant tumors. Loss of Alström and Usher syndrome gene expression, which are common underlying causes of deafness and blindness, suppresses ciliogenesis and HH signaling. Atypical protein kinase C iota/lambda (aPKC) is a GLI1 kinase with higher expression in advanced BCCs and we show that a constitutively active isoform drives HH pathway activity and mutually antagonizes primary cilia. Overexpression of the constitutively active aPKC variant can maintain HH pathway activity in the absence of primary cilia and can drive resistance to the SMO antagonist vismodegib regardless of cilia status. Finally, superficial BCCs display less primary cilia and higher aPKC expression, which is inversely correlated in nodular BCC subtypes. Our results suggest aPKC may serve as a biomarker for SMO inhibitor sensitivity and a target for clinical application.

Atypical protein kinase C iota (PKCλ/ι) ensures mammalian development by establishing the maternal–fetal exchange interface

In utero mammalian development relies on the establishment of the maternal–fetal exchange interface, which ensures transportation of nutrients and gases between the mother and the fetus. This exchange interface is established via development of multinucleated syncytiotrophoblast cells (SynTs) during placentation. In mice, SynTs develop via differentiation of the trophoblast stem cell-like progenitor cells (TSPCs) of the placenta primordium, and in humans, SynTs are developed via differentiation of villous cytotrophoblast (CTB) progenitors. Despite the critical need in pregnancy progression, conserved signaling mechanisms that ensure SynT development are poorly understood. Herein, we show that atypical protein kinase C iota (PKCλ/ι) plays an essential role in establishing the SynT differentiation program in trophoblast progenitors. Loss of PKCλ/ι in the mouse TSPCs abrogates SynT development, leading to embryonic death at approximately embryonic day 9.0 (E9.0). We also show that PKCλ/ι-mediated priming of trophoblast progenitors for SynT differentiation is a conserved event during human placentation. PKCλ/ι is selectively expressed in the first-trimester CTBs of a developing human placenta. Furthermore, loss of PKCλ/ι in CTB-derived human trophoblast stem cells (human TSCs) impairs their SynT differentiation potential both in vitro and after transplantation in immunocompromised mice. Our mechanistic analyses indicate that PKCλ/ι signaling maintains expression of GCM1, GATA2, and PPARγ, which are key transcription factors to instigate SynT differentiation programs in both mouse and human trophoblast progenitors. Our study uncovers a conserved molecular mechanism, in which PKCλ/ι signaling regulates establishment of the maternal–fetal exchange surface by promoting trophoblast progenitor-to-SynT transition during placentation.

Atypical Protein Kinase C iota (PKCλ/ι) Ensures Mammalian Development by Establishing the Maternal-Fetal Exchange Interface

In utero mammalian development relies on the establishment of the maternal–fetal exchange interface, which ensures transportation of nutrients and gases between the mother and the fetus. This exchange interface is established via development of multinucleated syncytiotrophoblast cells (SynTs) during placentation. In mouse, SynTs develop via differentiation of the trophoblast progenitor cells (TSPCs) of the placenta primordium and in human, SynTs are developed via differentiation of villous cytotrophoblast (CTB) progenitors. Despite the critical need in pregnancy progression, conserved signaling mechanisms that ensure SynT development are poorly understood. Herein, we show that Atypical Protein Kinase C iota (PKCλ/I) plays an essential role in establishing the SynT differentiation program in trophoblast progenitors. Loss of PKCλ/I in the mouse TSPCs abrogates SynT development leading to embryonic death at ~E9.0. We also show that PKCλ/I-mediated priming of trophoblast progenitors for SynT differentiation is a conserved event during human placentation. PKCλ/I is selectively expressed in the first-trimester CTBs of a developing human placenta. Furthermore, loss of PKCλ/I in CTB-derived human trophoblast stem cells (Human TSCs) impairs their SynT differentiation potential both in vitro and after transplantation in immunocompromised mice. Our mechanistic analyses indicate that PKCλ/I signaling maintains expression of GCM1, GATA2, and PPARγ, which are key transcription factors to instigate SynT differentiation programs in both mouse and human trophoblast progenitors. Our study uncovers a conserved molecular mechanism, in which PKCλ/I signaling regulates establishment of the maternal-fetal exchange surface by promoting trophoblast progenitor to SynT transition during placentation.