Differentiation efficiency of induced pluripotent stem cells depends on the number of reprogramming factors.

L?hle, Matthias,Hermann, Andreas,Glass, Hannes,Kempe, Andrea,Schwarz, Sigrid C,Kim, Jeong Beom,Poulet, Claire,Ravens, Ursula,Schwarz, Johannes,Sch?ler, Hans R,Storch, Alexander AlphaMed Press 2012 Stem cells Vol.30 No.3

<P>Reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) by retroviral overexpression of the transcription factors Oct4, Sox2, Klf4, and c-Myc holds great promise for the development of personalized cell replacement therapies. In an attempt to minimize the risk for chromosomal disruption and to simplify reprogramming, several studies demonstrated that a reduced set of reprogramming factors is sufficient to generate iPSC, albeit at lower efficiency. To elucidate the influence of factor reduction on subsequent differentiation, we compared the efficiency of neuronal differentiation in iPSC generated from postnatal murine neural stem cells with either one (Oct4; iPSC(1F-NSC) ), two (Oct4, Klf4; iPSC(2F-NSC) ), or all four factors (iPSC(4F-NSC) ) with those of embryonic stem cells (ESCs) and iPSC produced from fibroblasts with all four factors (iPSC(4F-MEF) ). After 2 weeks of coculture with PA6 stromal cells, neuronal differentiation of iPSC(1F-NSC) and iPSC(2F-NSC) was less efficient compared with iPSC(4F-NSC) and ESC, yielding lower proportions of colonies that stained positive for early and late neuronal markers. Electrophysiological analyses after 4 weeks of differentiation identified functional maturity in neurons differentiated from ESC, iPSC(2F-NSC) , iPSC(4F-NSC) , and iPSC(4F-MEF) but not in those from iPSC(1F-NSC) . Similar results were obtained after hematoendothelial differentiation on OP9 bone marrow stromal cells, where factor-reduced iPSC generated lower proportions of colonies with hematoendothelial progenitors than colonies of ESC, iPSC(4F-NSC) , and iPSC(4F-MEF) . We conclude that a reduction of reprogramming factors does not only reduce reprogramming efficiency but may also worsen subsequent differentiation and hinder future application of iPSC in cell replacement therapies.</P>

Cellular Adaptation to VEGF-Targeted Antiangiogenic Therapy Induces Evasive Resistance by Overproduction of Alternative Endothelial Cell Growth Factors in Renal Cell Carcinoma ¹ ²

Han, Kyung Seok,Raven, Peter A.,Frees, Sebastian,Gust, Kilian,Fazli, Ladan,Ettinger, Susan,Hong, Sung Joon,Kollmannsberger, Cristian,Gleave, Martin E.,So, Alan I. Neoplasia Press 2015 Neoplasia Vol.17 No.11

<P>Vascular endothelial growth factor (VEGF)–targeted antiangiogenic therapy significantly inhibits the growth of clear cell renal cell carcinoma (RCC). Eventually, therapy resistance develops in even the most responsive cases, but the mechanisms of resistance remain unclear. Herein, we developed two tumor models derived from an RCC cell line by conditioning the parental cells to two different stresses caused by VEGF-targeted therapy (sunitinib exposure and hypoxia) to investigate the mechanism of resistance to such therapy in RCC. Sunitinib-conditioned Caki-1 cells <I>in vitro</I> did not show resistance to sunitinib compared with parental cells, but when tested <I>in vivo</I>, these cells appeared to be highly resistant to sunitinib treatment. Hypoxia-conditioned Caki-1 cells are more resistant to hypoxia and have increased vascularity due to the upregulation of VEGF production; however, they did not develop sunitinib resistance either <I>in vitro</I> or <I>in vivo</I>. Human endothelial cells were more proliferative and showed increased tube formation in conditioned media from sunitinib-conditioned Caki-1 cells compared with parental cells. Gene expression profiling using RNA microarrays revealed that several genes related to tissue development and remodeling, including the development and migration of endothelial cells, were upregulated in sunitinib-conditioned Caki-1 cells compared with parental and hypoxia-conditioned cells. These findings suggest that evasive resistance to VEGF-targeted therapy is acquired by activation of VEGF-independent angiogenesis pathways induced through interactions with VEGF-targeted drugs, but not by hypoxia. These results emphasize that increased inhibition of tumor angiogenesis is required to delay the development of resistance to antiangiogenic therapy and maintain the therapeutic response in RCC.</P>

Targeting Integrin-Linked Kinase Suppresses Invasion and Metastasis through Downregulation of Epithelial-to-Mesenchymal Transition in Renal Cell Carcinoma

Han, Kyung Seok,Li, Na,Raven, Peter A.,Fazli, Ladan,Ettinger, Susan,Hong, Sung Joon,Gleave, Martin E.,So, Alan I. American Association for Cancer Research 2015 Molecular Cancer Therapeutics Vol.14 No.4

<P>Renal cell carcinoma (RCC) is the most common malignancy in the kidney. Antiangiogenic targeted therapies inhibit the progression of RCC, but have limited impacts on invasion or metastasis of tumor cells. Integrin-linked kinase (ILK) is a serine/threonine kinase implicated in the regulation of cell growth/survival, cell-cycle progression, epithelial–mesenchymal transition (EMT), invasion/migration, and angiogenesis. However, the role of ILK in RCC has not been evaluated. We investigated the role of ILK on cancer progression and metastasis and the therapeutic potential of ILK inhibition in RCC. Our investigation reveals that ILK is expressed at a low level in normal cells and low-stage RCC cells and is highly expressed in advanced and metastatic cells. Caki-1, a metastatic RCC cell line, showed higher expression of molecular EMT markers, including Snail and Zeb1, but decreased activity of GSK3β. Knockdown of ILK using small interference (si)-ILK minimally inhibited tumor proliferation and cell-cycle progression was not significantly affected. However, ILK knockdown suppressed the formation of stress fibers and focal adhesions and impeded phenotypic EMT markers, including cell migration and invasion, in Caki-1 and UMRC-3 cells. Finally, <I>in vivo</I> knockdown of ILK suppressed the progression, invasion, and metastasis of primary RCC in nude mice by downregulation of EMT markers (Snail, Zeb1, vimentin, and E-cadherin). Our results show that ILK may be essential for invasion and metastasis in RCC and regulates vimentin and E-cadherin expression by regulating the EMT-related transcription factors Snail and Zeb1. These results suggest that ILK may be a potential target in RCC. <I>Mol Cancer Ther; 14(4); 1024–34. ©2015 AACR</I>.</P>

New genus with two new species of the Family Nemesiidae (Araneae: Mygalomorphae) from Arunachal Pradesh, India

Manju Siliwal,Sanjay Molur,Robert Raven 국립중앙과학관 2015 Journal of Asia-Pacific Biodiversity Vol.8 No.1

The new genus, Damarchilus gen. nov., is proposed with descriptions of two new species, Damarchilus nigricus sp. nov. and Damarchilus rufus sp. nov., from northeast India. External characters for the new genus and new species are examined and illustrated. In addition, the natural history of the species is provided.

The Algal Revolution

Brodie, Juliet,Chan, Cheong Xin,De Clerck, Olivier,Cock, J. Mark,Coelho, Susana M.,Gachon, Claire,Grossman, Arthur R.,Mock, Thomas,Raven, John A.,Smith, Alison G.,Yoon, Hwan Su,Bhattacharya, Debashish Elsevier 2017 Trends in plant science Vol.22 No.8

<P>Algae are (mostly) photosynthetic eukaryotes that occupy multiple branches of the tree of life, and are vital for planet function and health. In this review, we highlight a transformative period in studies of the evolution and functioning of this extraordinary group of organisms and their potential for novel applications, wrought by high-throughput ‘omic’ and reverse genetic methods. We cover the origin and diversification of algal groups, explore advances in understanding the link between phenotype and genotype, consider algal sex determination, and review progress in understanding the roots of algal multicellularity. Experimental evolution studies to determine how algae evolve in changing environments are highlighted, as is their potential as production platforms for compounds of commercial interest, such as biofuel precursors, nutraceuticals, or therapeutics.</P> <P><B>Trends</B></P> <P>Application of modern ‘omic and genetic methods has significantly advanced our understanding of the origin, evolution, and metabolic potential of unicellular and multicellular algae, as well as their diverse modes of sexual reproduction.</P> <P>The GreenCut proteins, a conserved gene set in the Viridiplantae, are primarily plastid targeted and have key roles in the function and regulation of photosynthesis, including the maintenance of photosynthetic reaction complexes.</P> <P>Lab evolution experiments demonstrate the strong adaptability of microalgae to environmental changes that are associated with climate change, although it is unclear whether these results will hold in natural ecosystems.</P> <P>The development of algae as ‘cell factories’ promises to allow the production of not only endogenous molecules, but also non-native compounds such as high-value pigments, bulk chemicals, or even therapeutic proteins.</P>