dictyNews Volume 27 Number 07

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dictyNews 
Electronic Edition 
Volume 27, number 7 
September 1, 2006 

Please submit abstracts of your papers as soon as they have been 
accepted for publication by sending them to dicty@northwestern.edu 
or by using the form at 
http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. 

Back issues of dictyNews, the Dicty Reference database and other  
useful information is available at dictyBase - http://dictybase.org. 

 
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  Abstracts 
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Anti-leukemic activities of Dictyostelium secondary metabolites: A novel  
aromatic metabolite, 4-methyl-5-n-propylbenzene-1,3-diol, isolated from  
Dictyostelium mucoroides suppresses cell growth in human leukemia K562  
and HL-60 cells. 

Haruhisa Kikuchi, Yoshiteru Oshima, Aya Ichimura, Naomi Gokan, Aiko  
Hasegawa, Kohei Hosaka, & Yuzuru Kubohara 

 
Life Sciences, in press 

It has previously been shown that DIF-1, a differentiation-inducing factor  
of the cellular slime mold Dictyostelium discoideum, possesses antitumor  
activities in mammalian tumor cells and that neuronal differentiation of  
PC12 cells can be induced with furanodictines (FDs), aminosugar analogs  
found in D. discoideum, or dictyoglucosamines (DGs), N-acetyl glucosamine  
derivatives (DG-A from D. purpureum and DG-B from D. discoideum).  Thus,  
cellular slime molds are attractive natural resources that may provide  
valuable lead compounds to be utilized in the field of pharmacology and  
medicine.  In this study, we have isolated a novel aromatic compound,  
4-methyl-5-n-propylbenzene-1,3-diol (MPBD), from fruiting bodies of the  
cellular slime mold D. mucoroides and assessed the in vitro  
antiproliferative activities of MPBD, FDs, and DGs in human leukemia K562  
and HL-60 cells.  MPBD at 20-80 micro M dose-dependently suppressed cell  
growth in both K562 and HL-60 cells.  While FDs at 10-80 micro M did not  
affect cell growth, DGs at 10-40 micro M dose-dependently suppressed cell  
growth in the cells.  Although we failed to find the roles of FDs and DGs  
in the original organisms, MPBD at 5-20 micro M was found to promote stalk  
cell formation in D. discoideum.  The present results indicate that MPBD,  
DGs or their derivatives may have therapeutic potential in the treatment of  
cancer and confirm our expectations regarding cellular slime molds as drug  
resources. 

 
Submitted by: Yuzuru Kubohara [kubohara@showa.gunma-u.ac.jp] 
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Mechanically-induced actin-mediated rocketing of phagosomes  

Margaret Clarke1, Annette MŸller-Taubenberger2, 5, Kurt I. Anderson3, Ulrike  
Engel4, and GŸnther Gerisch2 

1Program in Molecular, Cell, and Developmental Biology, Oklahoma Medical  
Research Foundation, Oklahoma City, OK 73121 
2Max-Planck-Institut fŸr Biochemie, 82152 Martinsried, Germany 
3Max-Planck-Institut of Molecular Cell Biology and Genetics, 01037 Dresden,  
Germany 
4University of Heidelberg, Nikon Imaging Center, 69120 Heidelberg, Germany 
5Present address: Ludwig Maximilians University Munich, Institute for Cell  
Biology (ABI), 80336 MŸnchen, Germany 

1Corresponding author.  E-mail: clarkem@omrf.ouhsc.edu 

 
Molecular Biology of the Cell, in press. 

Actin polymerization can be induced in Dictyostelium by compressing the  
cells to bring phagosomes filled with large particles into contact with the  
plasma membrane.  Asymmetric actin assembly results in rocketing movement of  
the phagosomes.  We show that the compression-induced assembly of actin at  
the cytoplasmic face of the plasma membrane involves the Arp2/3 complex.  We  
also identify two other proteins associated with the mechanically-induced  
actin assembly.  The class I myosin MyoB accumulates at the plasma  
membrane-phagosome interface early during the initiation of the response,  
and coronin is recruited as the actin filaments are disassembling.  The  
forces generated by rocketing phagosomes are sufficient to push the entire  
microtubule apparatus forward and to dislocate the nucleus. 

 
Submitted by: Margaret Clarke [Margaret-Clarke@omrf.ouhsc.edu] 
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[End dictyNews, volume 27, number 7]