First Approach you can do
<br />
<itemstyle wrap="False"><br />
<headerstyle wrap="False" horizontaalign="Centre"></headerstyle><br />
The second approach is to only apply it to a column:
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<asp:boundcolumn datafield="" xmlns:asp="#unknown"><br />
<itemstyle wrap="False" horizontaalign="Left"></itemstyle><br />
<headerstyle wrap="False" horizontaalign="Centre"></headerstyle><br />