shp2pgsql -c -d -D -W LATIN1 -s 4269 -I 'path/to/shapefile.shp' my_table | psql -d mydb

SELECT ST_AsText(geom) FROM my_table LIMIT 1;

"MULTIPOLYGON(((-9619467.85573143 3856511.77685212,-9619466.74264784 3854145.2378255,-9619466.73474416 3854144.27900372 (...)"

"MULTIPOLYGON(((-123.1 45.1,-123.2 45.2, -123.3 45.3 (...)"

GEOGCS["WGS 84",DATUM["WGS_1984",SPHEROID["WGS
84",6378137,298.257223563,AUTHORITY["EPSG",
"7030"]],AUTHORITY["EPSG","6326"]],PRIMEM
["Greenwich",0,AUTHORITY["EPSG","8901"]],UNIT
["degree",0.0174532925199433,AUTHORITY["EPSG",
"9122"]],AUTHORITY["EPSG","4326"]]

shp2pgsql -c -d -D -W LATIN1 -s 3857 -I 'path/to/shapefile.shp' my_table | psql -d mydb

ALTER TABLE my_table
  ALTER COLUMN geom TYPE Geometry(Point,4326)
  USING ST_Transform(geom, 4326);