Shares of Zscaler IncZS.O soared 21.2% after the cloud security company raised its annual forecast. By Shreyashi Sanyal and Shristi Achar A May 8 (Reuters) - Wall Street's main indexes inched lower on Monday as Tyson Foods and Catalent led falls on the benchmark S&P 500 ahead of a key inflation reading this week, while a rebound in regional lenders ran out of steam by midday trading. "(Growth stocks are down) on nothing other than a mild profit-taking, given the strong move that we saw last week," said Michael James, managing director of equity trading at Wedbush Securities.