Sept 8 (Reuters) - GameStop Corp (GME.N), the videogame retailer at the center of this year"s "meme stock" trading frenzy, beat analysts" estimates for quarterly revenue on Wednesday, as vaccinations encouraged people to return to its stores. Net sales rose to $1.18 billion in the second quarter ended July 31 from $942 million a year earlier, above the average estimate of $1.12 billion by four analysts, according to IBES data from Refinitiv. The results come as investors closely track chairman and top shareholder Ryan Cohen"s efforts to build out the company"s online business to take on big-box retailers and revive its stores to bring back gamers.