PHP JSON_DECODE删除双引号中的双引号？

I'm using the hackernews api from http://api.ihackernews.com/. I'm getting the results via JSON.

I'm having problems with the php function json_decode(). It works fine, except if there is to many double quotes.

The error is with
"Ask PG: Will you post an update to "StartupIdeasWeu0027dLiketoFund"?" in:

{
 "title": "Ask PG: Will you post an update to "StartupIdeasWeu0027dLiketoFund"?",
 "url": "/comments/6014422",
 "id": 6014422,
 "commentCount": 58,
 "points": 214,
 "postedAgo": "12 hours ago",
 "postedBy": "awwstn"
}

How can I replace "Ask PG: Will you post an update to "StartupIdeasWeu0027dLiketoFund"?" with "Ask PG: Will you post an update to \"StartupIdeasWeu0027dLiketoFund\"?"?