ATP-Binding Cassette Transporters/antagonists & inhibitors; Cannabinoids/pharmacology; Neoplasm Proteins/antagonists & inhibitors; Plant Extracts/pharmacology; ATP Binding Cassette Transporter, Subfamily G, Member 2; ATP-Binding Cassette Transporters/genetics; ATP-Binding Cassette Transporters/metabolism; Adenosine Triphosphatases/metabolism; Animals; Cannabinoids/chemistry; Cannabinoids/isolation & purification; Cell Line; Cell Line, Tumor; Cell Survival/drug effects; Dose-Response Relationship, Drug; Dronabinol/analogs & derivatives; Dronabinol/pharmacology; Flow Cytometry; Humans; Immunoblotting; Inhibitory Concentration 50; Mice; Mitoxantrone/pharmacology; Neoplasm Proteins/genetics; Neoplasm Proteins/metabolism; Plant Extracts/chemistry; Plant Extracts/isolation & purification; Receptor, Cannabinoid, CB1/genetics; Receptor, Cannabinoid, CB1/metabolism; Reverse Transcriptase Polymerase Chain Reaction; Sulfasalazine/pharmacology; TRPV Cation Channels/genetics; TRPV Cation Channels/metabolism; Topotecan/pharmacology