Hematopoietic stem cells (HSCs) ensure the lifelong production of blood cells throughout a lifetime. Latexin (Lxn) is thought to have a tumor suppressor role and endogenously down-regulate the number of HSCs via increased apoptosis. Therewithal, Raptor, and Rictor are components of the mammalian target of rapamycin complex-1, and 2 (mTORC), which are the regulatory structures for cell growth. However, Lxn, Raptor, and Rictor-associated molecular mechanisms underlying leukemia-induced HSCs proliferation are largely unknown. Nowadays, chronic lymphocytic leukemia (CLL) remains the most common leukemia type in adults. Therefore, we investigated the serum levels of Lxn, Raptor, and Rictor in CLL patients. We randomized 40 patients with newly diagnosed, untreated CLL. Serum levels of Lxn, Raptor, and Rictor were examined using ELISA assay. The results showed that serum Lxn levels reduced in patients with CLL. Moreover, the Rictor level increased in association with the up-regulation of leukocytosis. Although there was a tendency for an increase of the Raptor levels, the differences did not reach statistical significance. The up-regulated Raptor and Rictor levels in CLL suggested that it was associated with cancer pathogenesis. However, decreased Lxn levels raised the question of whether the disease is secondary to epigenetic features or if it is caused by pathology related to Lxn. The negative correlation between Lxn and Raptor/Rictor levels can provide new methods for the treatment of CLL, which are likely to increase the quality of life and improve the prognosis of the disease. In conclusion, further clinical studies are needed to elucidate the role of Lxn and Raptor/Rictor with the newly defined molecular properties in hematological malignancies and the clinical implications of their use.
Key words: Latexin; Raptor; Rictor; mTOR; chronic lymphocytic leukemia