Powering an LED with a 170VDC Full Bridge Rectifier
It will not see -170V. It will have a relatively constant current from the positive bus as you probably initially expected. The problem is phantom- to do with your simulation. 

Suggest you put the ground in your simulation on the minus rail (and let the incoming AC supply float- that should work- if it doesn't, then add some very high value resistors to ground). I don't see a ground in the schematic- simulations should have a reference ground specified. This is not earth ground, it's just a reference point for SPICE to use for voltages. 

The LED is still effectively connected to the mains and it could lead to a shock hazard if it's not appropriately insulated. Also if the resistor or LED were to go open the light would go off, despite the capacitor being fully charged. I'll let you evaluate the safety concerns- there's no enough information to make conservative suggestions there.