**14. Analysis of the subcellular location of Kaiso in Mielode Chronic Leukemia (CML)**

Data obtained by our group in collaboration with the laboratory of stem cells of the Brazilian National Cancer Institute (INCA of Rio de Janeiro), headed by Dr. Eliana Abdelhay, shows the subcellular distribution of Kaiso by immunofluorescence on cell lines K562, used as a model of CML in the blastic phase. As it can be seen in Figure 2a, the expression of Kaiso is clearly cytoplasmic (Cofre, J., personal communications). As expected, cytoplasmic expression is significantly reduced when using the duplex for inhibition of Kaiso (Rnai) 48 hours after transfection (Figure 2b). As a control, we used the β-tubulin marker and demonstrated that the duplex Kaiso does not modify the expression of this marker after transfection for 48 hours (Figure 2 c and d) .

Fig. 2. Immunofluorescence analysis of kaiso expression. A.Kaiso was expressed in the cytoplasm of K562 cells (a human erythroleukemic line). B. siRNA-Kaiso efficiently downregulates cytoplasm expression after 48 hours transfection. As a control, we used the marker beta-tubulin and showed that siRNA-Kaiso does not modify the expression of this marker after 48 hours transfection.

Kaiso and Prognosis of Cancer in the Current Epigenetic Paradigm 121

as discussed in the chapter, proteins as connexin and Kaiso, which are essential for the diagnosis and prognosis of cancer, are always accumulated in the cytoplasm in cancer cells. This knowledge of endosomal compartments can be of paramount importance for the understanding of the molecular mechanisms by which diseases such as cancer initiate. For example, in the case of specific connexins, the tumor suppressor role could be related to the sequestration of these proteins in MVB during the onset of this tumor. Other related studies have proposed connexins as platforms for sequestering signaling proteins, suggesting that connexins might directly sequester MAPK (Mitogen-Activated Protein Kinase), CDK (Cyclin-dependent kinase), and Src (Proto-oncogene tyrosine-protein kinase) by SH2 and SH3 domains of the carboxyl terminal tail of Cx43 and, thus, act as a tumor suppressor

No studies have shown the association of connexins and endosomal compartments, and yet such studies could help understand the controversy of the expression of connexins in the plasma membrane during early metastasis, which can be related to deregulation

Therefore, a view focused on subcellular compartments and proteins modulating the epigenome can provide a greater understanding of the biology of malignant cells, as well as improve our approach to cancer treatment. It is known that cancer treatment is dictated by the stage of the disease, and that cancer treatment is more effective during the chronic phase of the disease. Unfortunately, clinical and molecular tests cannot predict disease progression, which can create an obstacle to diagnosis: the inability to identify subtypes of patients most likely to benefit from specific treatment options for specific stages of the disease, which would make it possible to offer a therapy targeted to a given cancer patient. Finally, the understanding of this new biology of disease progression can provide markers for clinical diagnosis and different approximations for better therapeutic strategies. Also, there is always hope that we'll be able to identify proteins and signaling pathways that may be useful as reliable prognostic markers of the disease and therapeutic targets in the near

The author thanks Dr. João Menezes for his contribution in the immunofluorescence of Kaiso, Dra. Eliana Abdelhay and Luciana Pizzatti for critical discussion of the results of cytoplasmic expression of Kaiso. The study was supported by Brazilian National Cancer

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mechanisms of cellular physiology of the endocytic compartment.

(Cofre & Bermudez, 2011).

**16. Future directions** 

**17. Acknowledgment** 

**18. References** 

Institute (INCA of Rio de Janeiro).

ISSN 1044-9523.

future.

These results are promising, first because they make it possible to relate the LMC disease to the presence of cytoplasmic Kaiso, and second, because the molecule may have a diagnostic value of clinical interest, not only in LMC, but also in other types of leukemia.
