Can't update CPT Fields using wp_update_post

I'm using the following array to update a CPT using wp_update_post() but the CPT fields are not updated. I'm not getting any errors.

$update_post = array(
'ID' => $post->ID,
'post_title' => $_POST['apodo'],
'plazo_de_renta' => $_POST['plazo_de_renta'],
'renta_mensual' => $_POST['renta_mensual'],
);