Regular expression - move content from tag A to tag B

I need help writing a regular expression that moves content from the title tag into the content tag.

This:

<xml>
 <item>
  <title>Title 1</title>
  <content>Text 1</content>
 </item>
 <item>
  <title>Title 2</title>
  <content>Text 2</content>
 </item>
</xml>

To this:

<xml>
 <item>
  <title>Title 1</title>
  <content>Title 1 Text 1</content>
 </item>
 <item>
  <title>Title 2</title>
  <content>Title 2 Text 2</content>
 </item>
</xml>