Hematopoiesis ; Humans ; Leukemia ; metabolism ; Oncogene Protein v-akt ; metabolism ; Signal Transduction

Phosphatidylinositol-3-kinase (PI3K) pathway signaling is an established oncogenic signal transduction pathway implicated in multiple malignancies. Therapeutic targeting of PI3K pathway components has improved outcomes in chronic lymphocytic leukemia, kidney cancer, breast cancer, and neuroendocrine tumors. Gastric cancers harbor some of the highest rates of oncogenic alterations in PI3K but attempts to translate this genomic observation have met with limited clinical success and novel approaches are needed. In the following review we discuss PI3K signaling, previous preclinical and clinical investigations in gastric cancer, and discuss future strategies aimed at overcoming resistance and improving efficacy. Identification and refinement of molecular tumor subtypes, development of predictive biomarkers along, and rational drug combination strategies are key to capitalizing on the therapeutic potential of PI3K pathway directed therapies in gastric cancers.
Biomarkers ; Breast Neoplasms ; Kidney Neoplasms ; Leukemia, Lymphocytic, Chronic, B-Cell ; Molecular Targeted Therapy ; Neuroendocrine Tumors ; Oncogene Protein v-akt ; Signal Transduction ; Stomach Neoplasms* ; TOR Serine-Threonine Kinases

Phosphatidylinositol-3-kinase (PI3K) pathway signaling is an established oncogenic signal transduction pathway implicated in multiple malignancies. Therapeutic targeting of PI3K pathway components has improved outcomes in chronic lymphocytic leukemia, kidney cancer, breast cancer, and neuroendocrine tumors. Gastric cancers harbor some of the highest rates of oncogenic alterations in PI3K but attempts to translate this genomic observation have met with limited clinical success and novel approaches are needed. In the following review we discuss PI3K signaling, previous preclinical and clinical investigations in gastric cancer, and discuss future strategies aimed at overcoming resistance and improving efficacy. Identification and refinement of molecular tumor subtypes, development of predictive biomarkers along, and rational drug combination strategies are key to capitalizing on the therapeutic potential of PI3K pathway directed therapies in gastric cancers.
Biomarkers ; Breast Neoplasms ; Kidney Neoplasms ; Leukemia, Lymphocytic, Chronic, B-Cell ; Molecular Targeted Therapy ; Neuroendocrine Tumors ; Oncogene Protein v-akt ; Signal Transduction ; Stomach Neoplasms* ; TOR Serine-Threonine Kinases

OBJECTIVETo extract two kinds of phenols 4-hydroxy-3, 5-dimethoxy-4-(2-oxopropyl) cyclohexa-2, 5-dien-l-one and 6-methoxy-5,7-dihydroxy coumarin (named as I and H compounds respectively) from Ajania salicifolia and to investigate their antioxidation and cytotoxicity to tumors and explore their pro-apoptosis mechanism.

METHODSThe antioxidant activities of two compounds were assessed by ABTS and DPPH radical-scavenging assays. Two compounds were evaluated for their cytotoxicity against human chronic myelogenous leukemia (K562) cells using the MIT assay. The expression of NF-kappaB P65 mRNA in K562 apoptotic cells was measured by reverse transcription-polymerase chain reaction (RT-PCR), real-time quantitative PCR. In addition, protein expression levels of the NF-ICB P65, p-Akt, Fas, P-catenina and E-cadherin were also measured by Western blot.

RESULTS(1) We found that compound I displayed significant inoxidizability, while compound II had no obvious antioxidizability. (2) In cytotoxicity experiments, compound I didn't display cytotoxicity while compound H displayed obvious cytotoxicity. (3) Compared with the blank group, the expression of NF-kappaB P65 mRNA in K562 cell after treatment with compound II was obviously up-regulated. (4) Compared with the blank group, the expression levels of NF-kappaB P65, Fas, beta-catenina and E-cadherin were significantly increased in compound II treated groups and it appeared obvious dose-effect relationship between the expression of protein and drug concentration.

CONCLUSIONTwo phenols have obvious antioxidizability and cytotoxicity respectively. On the one hand, the tumor-suppressing mechanism of compound II maybe act by up-regulation the expression of NF-kappaB P65 and Fas protein; thereby, affecting the classical Fas apoptosis signaling pathways. On the other hand, it can also up-regulate the expression of protein beta-catenin and E-cadherin, which participate in the adhesion between cells, and accordingly, playing an important role in preventing the proliferation and metastasis of cancer cells.

Apoptosis ; Asteraceae ; chemistry ; Cadherins ; metabolism ; Humans ; K562 Cells ; Oncogene Protein v-akt ; metabolism ; Phenols ; chemistry ; Signal Transduction ; Transcription Factor RelA ; metabolism ; Up-Regulation ; beta Catenin ; metabolism ; fas Receptor ; metabolism

OBJECTIVETo investigate the effect of anti-EGFR monoclonal antibody on the chemosensitivity of human colon cancer cells and explore the possible molecular mechanism.

METHODSThe inhibitory effect of irinotecan (CPT-11), oxaliplatin (L-OHP) and fluorouracil (5-Fu), used alone or in combination with anti-EGFR monoclonal antibody, on the proliferation of LoVo cells in vitro was assessed by MTT assay. The expressions of PI3K and Akt protein in the treated cells were examined by Western blotting, and their mRNA expressions were detected by RT-PCR.

RESULTSBoth h-R3 and C-225 treatments significantly increased the chemosensitivity of LoVo cells to irinotecan and oxaliplatin. 5-Fu and h-R3 coadministered showed a synergistic effect on the cells, but 5-Fu and C-225 had an antagonistic action. Treatment with C-225 or h-R3 resulted in lowered expressions of PI3K and Akt in LoVo cells.

CONCLUSIONAnti-EGFR monoclonal antibody can increase the chemosensitivity of human colon cancer cells to most chemotherapeutic drugs, and such effect might be attributed to the blocking of PI3K/Akt signaling pathway by these antibodies.

Antibodies, Monoclonal, Humanized ; therapeutic use ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Cell Line, Tumor ; Cetuximab ; Colonic Neoplasms ; drug therapy ; metabolism ; Humans ; Oncogene Protein v-akt ; metabolism ; Receptor, Epidermal Growth Factor ; immunology ; Signal Transduction

OBJECTIVETo observe the effect of the signal pathway of phosphoinositol-3-kinase (PI3K)/Akt-antypical protein kinase C(iotazeta) (aPKC(iotazeta))-Nuclear factor-E2 related factor (Nrf2) on gamma-glutamylcysteine synthetase (gamma-GCS) of the bronchial epithelial cells of rats after exposure to cigarette smoke extracts (CSE).

METHODSgamma-GCS, Nrf2, p-Akt and p-aPKC(iotazeta) proteins were semi-quantified by Western blot. gamma-GCS protein expression was assessed by immunocytochemistry. gamma-GCS mRNA expression was detected by reverse transcription-polymerase chain reaction (RT-PCR). Nrf2 protein was observed by immunofluorescence. The rate of the cells expressed p-Akt were analyzed by flow cytometry. GSH content and gamma-GCS activity were measured.

RESULTSGSH content, Nrf2 protein of nucleus, p-aPKC(iotazeta) protein, p-Akt protein and positive cells, gamma-GCS protein and mRNA and activity were significantly increased after exposure to CSE for 3 hours. aPK(iotazeta) inhibitor RO813220 significantly reduced the expression of p-aPKC(iotazeta) protein, gamma-GCS protein and mRNA and activity, but enhanced Nrf2 protein of cytoplasm expression, had no effect on p-Akt. p-Akt inhibitor LY294002 and RO813220 + LY294002 decreased p-aPKC(iotazeta) protein, p-Akt protein and positive cells, gamma-GCS protein and mRNA and activity expression, increased Nrf2 protein of cytoplasm expression. The correlation analysises demonstrated that there were a positive correlation between Nrf2 and gamma-GCS, p-Akt, p-aPKC(iotazeta), between p-Akt and Nrf2, p-aPKC(iotazeta), gamma-GCS, between p-aPKC(iotazeta) and Nrf2, p-Akt, gamma-GCS.

CONCLUSIONCSE might upregulate gamma-GCS expression through PI3K/Akt-aPKC(iotazeta)-Nrf2 signaling pathway in the bronchial epithelial cells of rats.

Animals ; Bronchi ; cytology ; enzymology ; Environmental Exposure ; adverse effects ; Epithelial Cells ; enzymology ; GA-Binding Protein Transcription Factor ; metabolism ; Glutamate-Cysteine Ligase ; genetics ; metabolism ; Isoenzymes ; metabolism ; Male ; Oncogene Protein v-akt ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Protein Kinase C ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Tobacco Smoke Pollution ; adverse effects

This study investigated the effects of SIRT1 gene knock-out on osteoarthritis in mice, and the possible roles of SREBP2 protein and the PI3K/AKT signaling pathway in the effects. Mice were randomly divided into a normal group and a SIRT1 gene knock-out group (6 mice in each group). In these groups, one side of the knee anterior cruciate ligament was traversed, and the ipsilateral medial meniscus was cut to establish an osteoarthritis model of knee joint. The countralateral synovial bursa was cut out, serving as controls. The knee joint specimens were then divided into four groups: SIRT1control group (group A, n=6); SIRT1osteoarthritis group (group B, n=6); SIRT1control group (group C, n=6); SIRT1osteoarthritis group (group D, n=6). HE staining, Masson staining, Safranin O-Fast Green staining and Van Gieson staining were used to observe the morphological changes in the articular cartilage of the knee. Immunohistochemical staining was employed to detect the expression of SIRT1, SREBP2, VEGF, AKT, HMGCR and type II collagen proteins. SA-β-gal staining was utilized to evaluate chondrocyte aging. The results showed clear knee joint cartilage destruction and degeneration in the SIRT1osteoarthritis group. The tidal line was twisted and displaced anteriorly. Type II collagen was destroyed and distributed unevenly. Compared with the SIRT1osteoarthritis group and SIRT1control group, SIRT1 protein expression was not obviously changed in the SIRT1osteoarthritis group (P>0.05), while the expression levels of the SREBP2, VEGF and HMGCR proteins were significantly increased (P<0.05) and the levels of AKT and type II collagen proteins were significantly decreased (P<0.05). SIRT1 gene knock-out may aggravate cartilage degeneration in osteoarthritis by activating the SREBP2 protein-mediated PI3K/AKT signalling pathway, suggesting that SIRT1 gene may play a protective role against osteoarthritis.
Animals ; Cartilage ; pathology ; Chondrocytes ; metabolism ; Collagen Type II ; metabolism ; Disease Models, Animal ; Humans ; Knee Joint ; metabolism ; pathology ; Mice ; Mice, Knockout ; Oncogene Protein v-akt ; genetics ; Osteoarthritis ; genetics ; pathology ; Phosphatidylinositol 3-Kinases ; genetics ; Signal Transduction ; genetics ; Sirtuin 1 ; genetics ; Sterol Regulatory Element Binding Protein 2 ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor A ; biosynthesis

Synthetic oligodeoxynucleotides (ODN) with a CpG-motif are recognized by Toll-like receptor 9 (TLR9) and pleiotropic immune responses are elicited. Stimulation of macrophages with TLR9 agonist prevented apoptosis induced by serum deprivation through increased expression of FLICE-like inhibitory protein (FLIP). CpG ODN-mediated anti-apoptosis depended on the TLR9-Akt-FoxO3a signaling pathway. Inhibition of TLR9 by small interfering (si) RNA or an inhibitor suppressed CpG ODN-mediated anti-apoptosis. Analysis of signaling pathways revealed that the anti-apoptotic effect of CpG ODN required phosphorylation of FoxO3a and its translocation from the nucleus to the cytosol. Overexpression of FoxO3a increased apoptosis induced by serum deprivation and CpG ODN blocked these effects through FLIP expression. In contrast, siRNA knock-down of FoxO3a decreased apoptosis by serum deprivation. In addition, Akt activation was involved in CpG ODN-induced phosphorylation of FoxO3a, expression of FLIP, and anti-apoptosis. Taken together, these results demonstrate the involvement of Akt-FoxO3a in TLR9-mediated anti-apoptosis and indicate that FoxO3a is a distinct regulator for FLIP expression.
Animals ; *Apoptosis ; CASP8 and FADD-Like Apoptosis Regulating Protein/*genetics/metabolism ; Cells, Cultured ; Forkhead Transcription Factors/genetics/*metabolism ; Macrophages/metabolism ; Mice ; Mice, Inbred C57BL ; Oligodeoxyribonucleotides/metabolism ; Oncogene Protein v-akt/metabolism ; RNA, Small Interfering/metabolism ; Signal Transduction ; Toll-Like Receptor 9/genetics/*metabolism

OBJECTIVE: To explore the association between expression of ADAM17 and cetuximad resistance in human colorectal cancer SW480 cells. METHODS: The expression of ADAM17 was detected using Western blotting in different human colorectal cancer cell lines, and the cells highly expressing ADAM17 were selected as the target cells. SW480 cells were transfected with ADAM17-siRNA 1 and ADAM17-siRNA 2 and the changes in the expression of ADAM17 protein were detected using Western blotting. SW480 cells were exposed to cetuximad for 24 h and the cell apoptosis was analyzed using flow cytometry. Transwell assay was used to examine the migration ability of SW480 cells with different expression levels of ADAM17; Western blotting was used to analyze the changes in the expressions of AKT signaling pathway-related proteins in the treated cells. RESULTS: The baseline expressions of ADAM17 were significantly higher in SW480 cells than in the other human colorectal cancer cell lines tested ( < 0.05). Both ADAM17-siRNA 1 and 2 effectively reduced the expression of ADAM17 protein in SW480 cells. Knockdown of ADAM17 with siRNA 1 significantly increased the sensitivity of SW480 cells to tocetuximad ( < 0.05), obviously inhibited the cell proliferation, migration and invasion, and significantly reduced the expressions of p-EGFR and p-AKT in the cells ( < 0.001). CONCLUSIONS ADAM17 knockdown obviously inhibits EGFR-AKT signaling pathway and increases the sensitivity of SW480 cells to tocetuximad.
ADAM17 Protein ; genetics ; metabolism ; Antineoplastic Agents, Immunological ; pharmacology ; Apoptosis ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Cetuximab ; pharmacology ; Colorectal Neoplasms ; drug therapy ; genetics ; metabolism ; pathology ; Drug Resistance, Neoplasm ; genetics ; ErbB Receptors ; metabolism ; Gene Knockdown Techniques ; Humans ; Neoplasm Invasiveness ; Oncogene Protein v-akt ; metabolism ; RNA, Small Interfering ; Signal Transduction ; Transfection ; methods

Deregulation of endothelial nitric oxide synthase (eNOS) plays an important role in the development of multiple cardiovascular diseases. Our recent study demonstrated that genistein supplementation attenuates pulmonary arterial hypertension in broilers by restoration of endothelial function. In this study, we investigated the molecular mechanism by using broiler pulmonary arterial endothelial cells (PAECs). Our results showed that genistein stimulated a rapid phosphorylation of eNOS at Ser(1179) which was associated with activation of eNOS/NO axis. Further study indicated that the activation of eNOS was not mediated through estrogen receptors or tyrosine kinase inhibition, but via a phosphatidylinositol 3-kinase (PI3K)/Akt-dependent signaling pathway, as the eNOS activity and related NO release were largely abolished by pharmacological inhibitors of PI3K or Akt. Thus, our findings revealed a critical function of Akt in mediating genistein-stimulated eNOS activity in PAECs, partially accounting for the beneficial effects of genistein on the development of cardiovascular diseases observed in animal models.
Animals ; Cell Line ; Chickens ; Disease Models, Animal ; Endothelium, Vascular/drug effects/*metabolism/pathology ; Enzyme Activation/drug effects ; Female ; Genistein/*pharmacology ; Humans ; Hypertension, Pulmonary/drug therapy/*metabolism/pathology ; Nitric Oxide Synthase Type III/genetics/*metabolism ; Oncogene Protein v-akt/*metabolism ; Phosphorylation ; Signal Transduction/drug effects