I believe you can if you buy an adapter although you will not get quite as good performance for gaming but if you want to do bitcoin mining it will not affect that performance.
Link to adaptor: http
/www.moddiy.com/products/PCI%252dExpress-PCI%252dE-x8-to-x16-Extension-Cable-Riser-(19cm).html?setCurrencyId=6&gclid=CjwKEAjw3fG4BRDsn9GAv7T2zEkSJACNJdjgvJwliGui1o5iGihLpPMibA0HQHQzVOw7hfHcui5CrhoCvfDw_wcB