Less than three years after it was founded and with no revenue on the books, Sana Biotechnology has filed to go public. It plans to trade on Nasdaq under the ticker SANA, with a plan to raise up to $150 million. And like Juno, Sana has big ambitions. It reported $459 million in cash, cash equivalents and marketable securities at the end of September 2020. Sana would become the latest in a string of Seattle area biotechnology companies to join the public ranks in recent months.