WORCESTER – A Las Vegas-based fast-casual restaurant, a spa and a bank plan to open sites downtown in a luxury apartment complex under construction on Front Street.

Protein House, Elizabeth Grady and Fidelity Cooperative Bank have signed leases for space at 145 Front Street at City Square, according to Roseland Residential Trust, the company building the $92 million complex.

Ivan Baron, Roseland’s chief legal officer, said recently in an interview that the developer was actively seeking amenities for the people who will be living at 145 Front when it opens in early 2018.

“With these retailers in place, the convenient lifestyle we set out to create at 145 Front continues to evolve,” Mr. Baron said Wednesday in a statement.

Luring new businesses downtown, especially those that that can cater to the small but growing number of residents, has been a goal of city officials as they work with developers to fill vacant lots and underused buildings.

“We appreciate that these businesses are investing in Worcester,” Michael E. Traynor, chief development officer for Worcester, said in a statement. “This is a further affirmation of the faith the development community and now the retail sector have in Worcester’s local economy.”

Roseland, which is a subsidiary of the real estate investment trust Mack-Cali Realty Corp., is developing 145 Front to include an outdoor swimming pool, a parking garage, a full-time concierge, a fitness center, lounge room, game room and other amenities. It said it signed the following companies to lease space:

• Protein House of Las Vegas is a growing and privately held franchised chain of restaurants aimed at fitness- and health-conscious consumers. It is leasing 2,185 square feet of space.

• Elizabeth Grady is a Medford-based privately held chain of skin care salons. It is leasing 1,791 square feet.

• Fidelity Cooperative Bank of Leominster has branches throughout Central Massachusetts and will lease 3,005 square feet.

Two additional spaces – each 1,700 square feet – remain available at 145 Front.

The new downtown residents will join a scene that is changing as private outside developers pour money into the city’s central core.

MG2 Group of Quincy is putting $20 million into renovations of its apartment buildings south of the Worcester Common and has plans to add restaurants at 50 Franklin St. and a beer garden at the site of the former Paris Cinema on Franklin Street.

XSS Hotels of Hookset, New Hampshire, has secured 110 Grill of Westford to develop a full-service restaurant at a new AC Hotel by Marriott under construction on Front Street.