Somatostatin and prostate cancer: role of somatostatin receptors in the control of tumor growth

The evidence that prostate cancer (PCa) expresses specific receptors for hormones and neuropeptides, including somatostatin (SRIF) receptors (SSRs) has driven the research towards the identification of new potential diagnostic/therapeutic paths besides the conventional treatment options. Although the first attempts has led to inconclusive results due to the heterogeneity of this tumor and to the complex mechanisms involved in the progression of PCa tumor growth, the potential role of SRIF and its synthetic analogues (SSAs) in the treatment of PCa represents an “open challenge” in the light of the new knowledge about SSR pathophysiology. Indeed, SRIF and SSAs can control tumor cell proliferation by two separate mechanisms: a direct mechanism through the activation of the five specific SSRs or an indirect mechanism through the inhibition of secretion of several growth factors and hormones responsible for tumor cell proliferation. Since new SSAs specific for each receptor subtype, as well as bi-specific compounds and panligands have been synthetized, the identification of alternative SSR targets on PCa cells and the consequent employment of these new specific molecules in the treatment of advanced PCa (alone or in combination with traditional treatment options), could improve the prognosis particularly of those patients not responding to (anti-) hormonal therapy (hormone-refractory PCa patients).