Mvc Application Cache

how can i build data cache for my Application with Repository Pattern? With lock object and persist for each session...

public sealed class NewsCache
{
    List<int> _tagsIds = null;
    static NewsCache _instance = new NewsCache();
    private static readonly object LockObject = new object();
    private readonly NewsManager _newsManager = new NewsManager(); 
    public static NewsCache Instance
    {
        get
        {
            lock (LockObject)
            {
                if (_instance == null)
                {
                    _instance = new NewsCache();
                }
                return _instance;
            }

        }
    }

    private NewsCache()
    {

    }
}