Casting a line into an article (8)
I believe the answer is:
throwing
'casting' is the definition.
('throw' can be a synonym of 'cast')
'a line into an article' is the wordplay.
'a line' becomes 'row' (a row or line of things).
'into' indicates putting letters inside.
'an article' becomes 'thing' (both can mean an object).
'row' inserted within 'thing' is 'THROWING'.
(Other definitions for throwing that I've seen before include "Chucking; unsettling" , "Puzzling" , "Propelling through the air" , "Projecting through the air" .)