Use JS-SDK recommended way of getting sender name.

src/molecules/MessageTile.js

@@ -20,7 +20,7 @@ module.exports = React.createClass({
         return (
             <div className="mx_MessageTile">
                 <MessageTimestamp ts={this.props.mxEvent.getTs()} />
-                <SenderProfile memberName={this.props.mxEvent.getSender()} />:
+                <SenderProfile mxEvent={this.props.mxEvent} />:
                 <TileType mxEvent={this.props.mxEvent} />
             </div>
         );

src/molecules/SenderProfile.js

@@ -2,10 +2,11 @@ var React = require('react');
 
 module.exports = React.createClass({
     render: function() {
-        var member = this.props.memberName;
+        var mxEvent = this.props.mxEvent;
+        var name = mxEvent.sender ? mxEvent.sender.name : mxEvent.getSender();
         return (
             <span className="mx_SenderProfile">
-                {member}
+                {name}
             </span>
         );
     },