class Product implements EntityInterface
{
    /**
     * @ORMId()
     * @ORMGeneratedValue()
     * @ORMColumn(type="integer", name="PROD_PKEY")
     */
    private $PROD_PKEY;

    /**
     * @ORMColumn(type="string", length=50)
     */
    private $PROD_Name;

    /**
     * @ORMColumn(type="string", length=50)
     */
    private $PROD_Code;

$product = new Product();
$product->setPRODName("Name");
$product->setPRODCode("Code");

$json = $this->serializer->serialize($product, 'json');

{
    "pRODName": "Name",
    "pRODCode": "Code",
}

{
    "PROD_Name": "Name",
    "PROD_Code": "Code",
}