The present invention provides a method of treating or preventing hepatitis C virus infection in a subject which comprises administering an effective amount of an agent to the subject, wherein the agent is capable of specifically binding to the HCV core protein so as to inhibit hepatitis C virus replication. The present invention also provides a method for determining whether a compound can treat or prevent hepatitis C virus infection in a subject, wherein the compound treats or prevents hepatitis C virus infection by specifically inhibiting the binding of HCV core protein and said agent so as to suppress hepatitis C virus replication. The present invention further provides a composition for inhibiting cell growth, comprises a HCV core protein or a variant thereof, wherein said HCV core protein or its variant inhibit cancer cell growth by inhibiting the cellular DEAD box proteins.