use strict;
use warnings;

my $line =  "some text Programming Languages: C++, Java Author: John Date Created: 20004-01-05 10:23";
my ($text) = $line =~ /
    ^[^:]*  # Skip everything from the start of line until the first :
    :\s+    # Skip the : and any trailing white space
    (       # Capture
        (?:     # Group, but don't capture
            (?!     # look ahead an fail to match if given pattern found
                \s+\w+: # Pattern to fail on - space word :
            ).      # Capture a character if the look ahead didn't fail
        )*      # Do it as many times as possible
    )       # Close the capture
    /x; # x flag ignores most white space and allows comments

print $text;