The present invention provides methods for treating cancer using GRK2 inhibitors such as small molecule inhibitors of GRK2 among others. The invention also features compositions containing GRK2 inhibitors, methods of diagnosing patients with GRK2-associated cancer and methods of predicting the response of cancer in a subject to treatment with GRK2 inhibitors.

The current invention is methods and assays for detecting and/or measuring the modification, i.e., activation or inhibition, of a receptor of interest, without the need to modify the receptor with a label or a tag. The invention uses proteins that move, translocate, are recruited and/or bind to the receptor of interest when the receptor is modified, and proteins in proximity to and/or in the same compartment as the receptor of interest. The proteins are attached or linked to polypeptides that result from the unique cleavage of a modified Oplophorus luciferase. When the proteins are in proximity allowing the unique polypeptides to recombine, a luminescent signal is generated. The invention also includes vector encoding these proteins, cells expressing these proteins, compositions, system and kits.

The current invention is methods and assays for detecting and/or measuring the modification, i.e., activation or inhibition, of a receptor of interest, without the need to modify the receptor with a label or a tag. The invention uses proteins that move, translocate, are recruited and/or bind to the receptor of interest when the receptor is modified, and proteins in proximity to and/or in the same compartment as the receptor of interest. The proteins are attached or linked to polypeptides that result from the unique cleavage of a modified Oplophorus luciferase. When the proteins are in proximity allowing the unique polypeptides to recombine, a luminescent signal is generated. The invention also includes vector encoding these proteins, cells expressing these proteins, compositions, system and kits.

An osteoarthritis progression inhibitor contains, as active substances, a G protein-coupled receptor kinase 5 inhibitor, and hyaluronic acid or a pharmaceutically acceptable salt thereof. The G protein-coupled receptor kinase 5 inhibitor may be Amlexanox. The osteoarthritis progression inhibitor may be administered by intraarticular injection. An osteoarthritis progression inhibition kit contains a G protein-coupled receptor kinase 5 inhibitor, and hyaluronic acid or a pharmaceutically acceptable salt thereof.