Helena Christensen holds up stick (4)
I believe the answer is:
'stick' is the definition.
(I know that cane is a type of walking stick)
'helena christensen holds up' is the wordplay.
'holds' says the answer is hidden in the clue.
'up' says the letters should be written backwards (in down clue: letters go upwards).
'enac' can be found hidden inside 'helena christensen'.
'enac' in reverse letter order is 'CANE'.
(Other definitions for cane that I've seen before include "A light rod once used for punishment" , "Staff < with walking-stick" , "A stick to lean on" , "Birch" , "Type of sugar; beat" .)