The present invention relates to a short peptide-based therapeutic agent and a medicinal composition including the same for inhibiting activities of cancer cells, which includes at least one short peptide listed as SEQ ID NOs: 1 and 2, either of which is unglycosylated and has no more than 40 amino acid residues, thereby specifically reducing or inhibiting activities of cancer cells such as the cancer cell proliferation, cancer stemness, cell migration, cancer cell invasion, metastasis or drug resistance.