[Expression of sperm-specific glyceraldehyde-3-phosphate dehydrogenase in melanoma cells changes their energy metabolism]. / Ékspressiia spermospetsifichnoi glitseral'degid-3-fosfatdegidrogenazy v melanomnykh kletkakh izmeniaet ikh énergeticheskii obmen.

The somatic isoform of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH; EC1.2.1.12) is involved in such crucial for cancer cells development pathways as induction of apoptosis and glycolytic regulation. At the same time, sperm-specific isoform (GAPDHS) does not exhibit all the same functions as somatic enzyme. The expression of sperm-specific GAPDH without N-terminal domain in some melanoma cells along with somatic isoenzyme, shown in our previous work, has led to the proposal of this unusual enzyme's possible role in regulation of cancer cells glycolysis. In the presented work we have tested production of GAPDHS in 13 additional melanoma cell lines by immunoblotting. We have also gathered data on energy metabolism in 5 selected cell lines by evaluation of glucose uptake and lactate production in differing conditions. We have demonstrated that in standard cultivation media glucose uptake by MelP cells, producing substantial amounts of GAPDHS protein was higher than in MelKor cells, producing lesser amounts of GAPDHS. All other analyzed cell lines that do not produce GAPDHS (MelMS, MelSi and Malme3M) had even a lower glucose uptake rate.

[Functional properties of the WNT11 new isoform, expressed in colon carcinoma cell line HT29].

Colon carcinoma is a common type of neoplastic transformation. Mechanisms of its establishment and progression have been studying for several decades. Aberrant activation of the canonical Wnt signaling is frequently observed in colon carcinoma cells. Moreover, expression of the "noncanonical" Wnt ligands is also detected in this type of cancer. However, the implication of the noncanonical Wnt signaling in carcinogenesis and colorectal cancer (CRC) progression is still unclear. Here, to elucidate the characteristic features of the noncanonical Wnt signaling activation in CRC the expression of the "noncanonical" ligand hWnt11 has been studied. It was shown for the first time that expression of the hWnt11 in CRC is accompanied by the alternative splicing. The new hWnt11 isoform (hWnt11sp3) has been identified. Unlike to hWnt11, this isoform is not secreted and lacks the ability to inhibit the canonical Wnt signaling. Considering the canonical Wnt signaling inhibiting activity of hWnt11, different functional properties of the ligand and its isoform may reflect a special role of the alternative splicing in carcinogenesis and tumor progression. Thus, due to the difference in their functional properties an existence of several Wnt isoforms should be taken into account for the investigation of the role of Wnt ligands.

[Nuclear beta-catenin localization is not sufficient for canonical Wnt signaling activation in human meianoma cell lines].

In most cases, advanced stages of melanoma are practically incurable due to high metastatic potential of tumor cells. Multiple observations support the idea that aberrations in Wnt signaling pathway play a significant role in melanoma development and progression. Canonical Wnt signaling activation results in stabilization and accumulation of the major effector molecule called beta-catenin. Mutations promoting beta-catenin stabilization and, thereby, activation of canonical Wnt signaling pathway are frequently found in different cancers, but rarely observed in melanomas. Nevertheless, beta-catenin nuclear and cytoplasmic accumulation is the feature of many human melanoma cell lines and original tumors. That is why, the aim of the investigation was to elucidate the relation between beta-catenin intracellular localization and activity status of Wnt signaling pathway in human melanoma cell lines. Ten human melanoma cell lines were characterized on the basis of the following parameters: canonical Wnt ligand expression, intracellular beta-catenin localization, and activity status of canonical Wnt signaling pathway. Here, it has been demonstrated that nuclear localization of beta-catenin does not always correspond to active status canonical Wnt signaling pathway. Moreover, in the majority of cell lines with nuclear beta-catenin canonical Wnt signaling can't be activated by exogenous expression of an appropriate ligand. Human melanoma cell lines differ in activity of canonical Wnt signaling pathway as well as in mechanisms of its regulation. Therefore, the pathway-targeted potential antineoplastic therapy requires the formation of a "molecular pattern of cancer" for localization of the defect in Wnt signaling cascade in the each case.