Yes, it's possible. 1 way:
In MT4, create a script to listen for the new price from your Excel spreadsheet using your favourite IPC method for communiion. There are many different IPC methods for sending messages between apps, but pipes may be a fantastic selection for this task. When a new price is obtained, the script may draw the line in the appropriate price. There are multiple examples of the type of functionality in this forum (search for named pipes).
In Excel, write code to deliver the new price to MT4 through precisely the exact same IPC method you employed in the MT4 script. See the Worksheet.Change or even Worksheet.Calculate occasions depending on your needs.