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dictyNews Volume 41 Number 12
dictyNews
Electronic Edition
Volume 41, number 12
June 12, 2015
Please submit abstracts of your papers as soon as they have been
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=========
Abstracts
=========
Derivatives of Dictyostelium differentiation-inducing factors inhibit
lysophosphatidic acidÐstimulated migration of murine osteosarcoma
LM8 cells
Yuzuru Kubohara*, Mayumi Komachi, Yoshimi Homma, Haruhisa Kikuchi,
Yoshiteru Oshima
* Corresponding author: Juntendo University Graduate School of Health
and Sports Science, Inzai 270-1695, Japan.
BBRC, in press
Osteosarcoma is a common metastatic bone cancer that predominantly
develops in children and adolescents. Metastatic osteosarcoma remains
associated with a poor prognosis; therefore, more effective anti-
metastatic drugs are needed. Differentiation-inducing factor-1 (DIF-1),
-2, and -3 are novel lead anti-tumor agents that were originally
isolated from the cellular slime mold Dictyostelium discoideum. Here
we investigated the effects of a panel of DIF derivatives on
lysophosphatidic acid (LPA)-induced migration of mouse osteosarcoma
LM8 cells by using a Boyden chamber assay. Some DIF derivatives such
as Br-DIF-1, DIF-3(+2), and Bu-DIF-3 (5Ð20 microM) dose-dependently
suppressed LPA-induced cell migration with associated IC50 values of
5.5, 4.6, and 4.2 microM, respectively. On the other hand, the IC50
values of Br-DIF-1, DIF-3(+2), and Bu-DIF-3 versus cell proliferation
were 18.5, 7.2, and 2.0 microM, respectively, in LM8 cells, and >20,
14.8, and 4.3 microM, respectively, in mouse 3T3-L1 fibroblasts
(non-transformed). Together, our results demonstrate that Br-DIF-1 in
particular may be a valuable tool for the analysis of cancer cell
migration, and that DIF derivatives such as DIF-3(+2) and Bu-DIF-3 are
promising lead anti-tumor agents for the development of therapies that
suppress osteosarcoma cell proliferation, migration, and metastasis.
Submitted by Yuzuru Kubohara [ykuboha@juntendo.ac.jp]
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A simple retroelement based knock-down system in Dictyostelium:
further insights into RNA interference mechanisms.
Michael Friedrich1¦, Doreen Meier1¦, Isabelle Schuster1 and
Wolfgang Nellen1, #a*
1Abt. Genetik, FB 10, Universitaet Kassel, Kassel, Germany
#a Current address: Dept. of Biology, Brawijaya University, Malang,
East Java, Indonesia
* Corresponding author
E-Mail: nellen@uni-kassel.de
¦ These authors contributed equally to this work.
PLOS ONE, accepted
Characteristics of DIRS-1 mediated knock-downs
We have previously shown that the most abundant Dictyostelium
discoideum retroelement DIRSÐ1 is suppressed by RNAi mechanisms.
Here we provide evidence that both inverted terminal repeats have
strong promoter activity and that bidirectional expression apparently
generates a substrate for Dicer. A cassette containing the inverted
terminal repeats and a fragment of a gene of interest was sufficient
to activate the RNAi response, resulting in the generation of ~21 nt
siRNAs, a reduction of mRNA and protein expression of the respective
endogene. Surprisingly, no transitivity was observed on the endogene.
This was in contrast to previous observations, where endogenous siRNAs
caused spreading on an artificial transgene. Knock-down was successful
on seven target genes that we examined. In three cases a phenotypic
analysis proved the efficiency of the approach. One of the target genes
was apparently essential because no knock-out could be obtained, the
RNAi mediated knock-down, however, resulted in a very slow growing
culture indicating a still viable reduction of gene expression.
Advantages of the DIRS-1 Ð RNAi system
The knock-down system required a short DNA fragment (~400 bp) of the
target gene as an initial trigger. Further siRNAs were generated by
RdRPs since we have shown some siRNAs with a 5Õ-triphosphate group.
Extrachromosomal vectors facilitate the procedure and allowed for
molecular and phenotypic analysis within one week. The system provides
an efficient and rapid method to reduce protein levels including those
of essential genes.
Submitted by Wolfgang Nellen [nellen@uni-kassel.de]
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[End dictyNews, volume 41, number 12]
