AKT as locus of fragility in robust cancer system

Local Anesthetic Lidocaine and Cancer: Insight Into Tumor Progression and Recurrence

Cancer is a leading contributor to deaths worldwide. Surgery is the primary treatment for resectable cancers. Nonetheless, it also results in inflammatory response, angiogenesis, and stimulated metastasis. Local anesthetic lidocaine can directly and indirectly effect different cancers. The direct mechanisms are inhibiting proliferation and inducing apoptosis via regulating PI3K/AKT/mTOR and caspase-dependent Bax/Bcl2 signaling pathways or repressing cytoskeleton formation. Repression invasion, migration, and angiogenesis through influencing the activation of TNFα-dependent, Src-induced AKT/NO/ICAM and VEGF/PI3K/AKT signaling pathways. Moreover, the indirect influences are immune regulation, anti-inflammation, and postoperative pain relief. This review summarizes the latest evidence that revealed potential clinical benefits of lidocaine in cancer treatment to explore the probable molecular mechanisms and the appropriate dose.

Switching to BCL-6 Negativity in Relapsed Diffuse Large B Cell Lymphoma Correlated with More Aggressive Disease Course

Diffuse large B-cell lymphoma (DLBCL) is the most frequent, complex and heterogeneous lymphoma of adulthood. Heterogeneity is expressed at clinical, genetic, and molecular levels. It is known that BCL-6 expression is a favorable prognostic factor in DLBCL. However, the underlying mechanisms of BCL-6 expression in DLBCL relapse are not yet elucidated. Here, we present so far undescribed clinical phenomenon of switching BCL-6(+) protein expression into BCL-6(-) expression in 19 of 41 relapsed DLBCL patients. The switch in relapsed DLBCL was associated with more aggressive clinical course of the disease. Bone marrow infiltration and high IPI risk were more often present in BCL-6(-) patients. Significantly increased biochemical parameters, such as LDH, beta-2 macroglobulin, CRP, and ferritin have been found, as well as significantly decreased serum Fe, TIBC, and hemoglobin. A Ki-67 proliferation marker was considerably high in relapsed DLBCL, but without significant differences between BCL-6(+) and BCL-6(-) groups of patients. Thus, switching of the positive into negative BCL-6 expression during DLBCL relapse could be used as a prognostic factor and a valuable criterion for treatment decision.

AKT as locus of cancer multidrug resistance and fragility

Complexity and robustness of cancer hypoxic microenvironment are supported by the robust signaling networks of autocrine and paracrine elements creating powerful interactome for multidrug resistance. These elements generate a positive feedback loops responsible for the extreme robustness and multidrug resistance in solid cancer, leukemia, myeloma, and lymphoma. Phosphorylated AKT is a cancer multidrug resistance locus. Targeting that locus by oxidant/antioxidant balance modulation, positive feedback loops are converted into negative feedback loops, leading to disappearance of multidrug resistance. This is a new principle for targeting cancer multidrug resistance by the locus chemotherapy inducing a phenomenon of loops conversion.

AKT as locus of cancer positive feedback loops and extreme robustness

A positive feedback loops induce extreme robustness in metastatic cancer, relapsed leukemia, myeloma or lymphoma. The loops are generated by the signaling interactome networks of autocrine and paracrine elements from cancer hypoxic microenvironment. The elements of the networks are signaling proteins synthesized in hypoxic microenvironment such as the vascular endothelial growth factor, HIF-1α, hepatocyte growth factor, and molecules nitric oxide and H(2)O(2). The signals from upstream or rebound downstream pathways are amplified by the short or wide positive feedback loops, hyperstimulating AKT-inducing cancer extreme robustness. Targeting the phosphorylated AKT locus by an oxidant/antioxidant modulation induces collapse of positive feedback loops and establishment of negative feedback loops leading to stability of the system and disappearance of cancer extreme robustness. This is a new principle for the conversion of cancer positive loops into negative feedback loops by the locus chemotherapy.

Increased angiogenesis-associated poor outcome in acute lymphoblastic leukemia: a single center study

Angiogenesis in solid tumors is important for tumor growth, invasion, and metastasis. However, angiogenesis plays also an important role in hematological malignancies. We have analyzed the expression of vascular endothelial growth factor (VEGF) in the leukemic blast cells and microvessel density (MVD) in the bone marrow biopsy samples of the patients with acute lymphoblastic leukemia (ALL). Bone marrow MVD of the patients with ALL was significantly higher compared with normal controls and complete remission (P<0.001), but slightly lower than in patients with relapsed ALL (P>0.05). The bone marrow blast VEGF expression was significantly higher in newly diagnosed ALL patients, with predominant strong VEGF expression as compared with complete remission patients (who had negative or weak VEGF expression) (P<0.05), whereas initial values were slightly lower than in relapsed patients. There was a strong positive correlation between VEGF expression and MVD at presentation of ALL. Stronger expression of VEGF on blast cells indicates shorter overall survival in ALL. Furthermore, initial values of MVD had positive correlation with overall survival and leukemia-free survival (P=0.024 and P=0.017, respectively). Our data suggest that increased angiogenesis (confirmed by immunohistochemical expression of VEGF in leukemic blasts), and MVD may play an important role in the pathophysiology of ALL with prognostic implications. Thus, targeting VEGF pathway may bring the new approach for ALL treatment-using antiangiogenic drugs and tyrosine kinase inhibitors in combination with standard chemotherapy regimens.

AKT as locus of cancer angiogenic robustness and fragility

Angiogenesis get full robustness in metastatic cancer, relapsed leukemia or lymphoma when complex positive feedback loop signaling systems become integrative. A cancer hypoxic microenvironment generates positive loops inducing formation of the vascular functional shunts. AKT is an upstream angiogenic locus of integrative robustness and fragility activated by the positive loops. AKT controls two downstream nodes the mTOR and NOS in nodal organization of the signaling genes. AKT phosphorylation is regulated by a balance of an oxidant/antioxidant. Targeting AKT locus represents new principle to control integrative angiogenic robustness by the locus chemotherapy.

Differential apoptotic response of human cancer cells to organoselenium compounds

PURPOSE

Selenium (Se) compounds are well known to inhibit cell proliferation and induce cell death in human cancer cells. Respective chemical forms of Se are intracellularly metabolized via complicated pathways, which target distinct molecules and exhibit varying degrees of anti-carcinogenicity in different cancer types; however, the precise mechanisms by which Se activates apoptosis remain poorly understood.

METHODS

The effects of Se compounds, Se-methylselenocysteine (MSC), selenomethionine (SeMet), and selenite on cell proliferation, apoptosis and its pathway in established human carcinoma cell lines (HSC-3, -4, A549, and MCF-7) were investigated. Cancer cells were treated with each Se compound during different periods. Cell apoptosis, caspase activity and ER stress markers were analyzed by flow cytometric or immunoblotting analysis, respectively.

RESULTS

We examined four cell lines for their sensitivity to MSC and SeMet in comparison with selenite. SeMet increased apoptotic cells in p53-positive A549 cells, whereas MSC increased apoptotic cells in p53-mutated HSC-3 cells. High activities of caspase-3, -8 and -9 were observed during apoptosis, and a pan-caspase inhibitor, z-VAD-fmk, rescued the cell viability of HSC-3 cells exposed to MSC. In addition, the occurrence of endoplasmic reticulum (ER) stress was suggested by the observation that levels of phosphorylated eIF2alpha and caspase-12 activity are increased in Se-treated cells. Selenite and MSC were accompanied with the concurrent reduction of phosphorylated Akt levels, and the inhibitory effects of these Se compounds on vascular endothelial growth factor expression were observed with identical patterns.

CONCLUSION

The present findings demonstrate that Se-induced apoptosis in carcinoma cells is basically a caspase-dependent process involving complicated mechanisms. Activation of both the intrinsic apoptotic pathway and ER stress pathway plays a major and concurrent role, while p53 activation seems to have only a functional role in SeMet.

Metabolic regulation and redox activity as mechanisms for angioprevention by dietary phytochemicals

The existence of active principles in numerous foods and beverages has been recognized by traditional medicines worldwide after centuries of empirical trial. Epidemiological studies support the concepts linking diet to survival, particularly in the incidence rates of specific cancers. Molecular studies have provided evidence that a wide range of food-derived phytochemicals and other diet-associated compounds or their synthetic derivatives represent a cornucopia of potential new compounds for prevention and treatment of chronic or acute diseases. Many have entered clinical practice or are under clinical testing. A remarkable property shared by several phytochemicals is the capacity to restrain inflammation and angiogenesis, two complex physiologic processes kept under control by strict rules, which can backfire in cancer and in pathologic conditions such as metabolic, cardiovascular and neurological disorders. We termed this concept "angioprevention". Here, we discuss recent findings on the metabolic effects of several phytochemicals with anticancer properties. The different molecular targets shared by these compounds seem to converge on crosstalking signaling networks involved in controlling energy metabolism through a redox-regulated code. The redox imbalance produced in the tissue microenvironment elicits an adaptive response that seems to provide cytoprotective effects potentially beneficial in cardiovascular and neurological disorders or energy balancing effects in metabolic disorders. However, in transformed and overt tumor cells, this redox imbalance favors cell death while curbing tumor inflammation and angiogenesis, thus engaging an overall antitumor response. These concepts provide a broader framework for pharmacological application of phytochemical-derived drugs against cancer.

Roles of ERK, PI3 kinase, and PLC-gamma pathways induced by overexpression of translationally controlled tumor protein in HeLa cells

We reported previously that translationally controlled tumor protein (TCTP) is a cytoplasmic repressor of Na,K-ATPase in HeLa cells. In the current study, we showed that TCTP overexpression using adenovirus as vehicle, induced partial inhibition of Na,K-ATPase; phosphorylation of EGFR tyrosine residues 845, 992,1068, and 1148; activation of Ras/Raf/ERK pathway; activation of PI3K/Akt pathway; and phosphorylation of PLC-gamma in HeLa cells. Specific inhibition of PI3K/Akt pathway in contrast to the inhibition of ERK,significantly decreased TCTP overexpression-induced survival signal. Inhibition of PLC-gamma pathway significantly decreased TCTP overexpression-induced cell migration but inhibition of ERK had less effect. These results suggest that TCTP plays a key physiological role in cell survival through Akt pathway and migration through PLC-gamma pathway.