R-Etodolac decreases beta-catenin levels along with survival and proliferation of hepatoma cells

Molecular signature and therapeutic perspective of the epithelial-to-mesenchymal transitions in epithelial cancers

The mechanisms involved in the epithelial to mesenchymal transition (EMT) are integrated in concert with master developmental and oncogenic pathways regulating in tumor growth, angiogenesis, metastasis, as well as the reprogrammation of specific gene repertoires ascribed to both epithelial and mesenchymal cells. Consequently, it is not unexpected that EMT has profound impacts on the neoplastic progression, patient survival, as well as the resistance of cancers to therapeutics (taxol, vincristine, oxaliplatin, EGF-R targeted therapy and radiotherapy), independent of the "classical" resistance mechanisms linked to genotoxic drugs. New therapeutic combinations using genotoxic agents and/or EMT signaling inhibitors are therefore expected to circumvent the chemotherapeutic resistance of cancers characterized by transient or sustained EMT signatures. Thus, targeting critical orchestrators at the convergence of several EMT pathways, such as the transcription pathways NF-kappaB, AKT/mTOR axis, MAPK, beta-catenin, PKC and the AP-1/SMAD factors provide a realistic strategy to control EMT and the progression of human epithelial cancers. Several inhibitors targeting these signaling platforms are already tested in preclinical and clinical oncology. In addition, upstream EMT signaling pathways induced by receptor and nonreceptor tyrosine kinases (e.g. EGF-R, IGF-R, VEGF-R, integrins/FAK, Src) and G-protein-coupled receptors (GPCR) constitute practical options under preclinical research, clinical trials or are currently used in the clinic for cancer treatment: e.g. small molecule inhibitors (Iressa: targeting selectively the EGF-R; CP-751,871, AMG479, NVP-AEW541, BMS-536924, PQIP, AG1024: IGF-R; AZD2171, ZD6474: VEGF-R; AZD0530, BMS-354825, SKI606: Src; BIM-46174: GPCR; rapamycin, CCI-779, RAD-001: mTOR) and humanized function blocking antibodies (Herceptin: ErbB2; Avastin: VEGF-A; Erbitux: EGF-R; Abegrin: alphavbeta3 integrins). We can assume that silencing RNA and adenovirus-based gene transfer of therapeutic miR and dominant interferring expression vectors targeting EMT pathways and signaling elements will bring additional ways for the treatment of epithelial cancers. Identification of the factors that initiate, modulate and effectuate EMT signatures and their underlying upstream oncogenic pathways should provide the basis of more efficient strategies to fight cancer progression as well as genetic and epigenetic forms of drug resistance. This goal can be accomplished using global screening of human clinical tumors by EMT-associated cDNA, proteome, miRome, and tissue arrays.

Drug development against metastasis-related genes and their pathways: a rationale for cancer therapy

It is well recognized that the majority of cancer related deaths is caused by metastatic diseases. Therefore, there is an urgent need for the development of therapeutic intervention specifically targeted to the metastatic process. In the last decade, significant progress has been made in this research field, and many new concepts have emerged that shed light on the molecular mechanism of metastasis cascade which is often portrayed as a succession of six distinct steps; localized invasion, intravasation, translocation, extravasation, micrometastasis and colonization. Successful metastasis is dependent on the balance and complex interplay of both the metastasis promoters and suppressors in each step. Therefore, the basic strategy of our interventions is aimed at either blocking the promoters or potentiating the suppressors in this disease process. Toward this goal, various kinds of antibodies and small molecules have been designed. These include agents that block the ligand-recepter interaction of metastasis promoters (HGF/c-Met), antagonize the metastasis-promoting enzymes (AMF, uPA and MMP) and inhibit the transcriptional activity of metastasis promoter (beta-Catenin). On the other hand, the intriguing roles of metastasis suppressors and their signal pathways have been extensively studied and various attempts have been made to potentiate these factors. Small molecules have been developed to restore the expression or mimic the function of metastasis-suppressor genes such as NM23, E-cadherin, Kiss-1, MKK4 and NDRG1, and some of them are under clinical trials. This review summarizes our current understanding of the molecular pathway of tumor metastasis and discusses strategies and recent development of anti-metastatic drugs.

siRNA-mediated beta-catenin knockdown in human hepatoma cells results in decreased growth and survival

beta-Catenin, the chief oncogenic component of the canonical Wnt pathway, is known to be involved in a variety of cancers, including hepatocellular carcinoma (HCC). Although the mechanism of beta-catenin activation in HCC is multifactorial, it is indisputably implicated at various stages of hepatocarcinogenesis, making it an attractive therapeutic target. Here we investigate the effect of small interfering RNA-mediated beta-catenin knockdown on the growth and survival of human hepatoma cell lines with (HepG2) and without (Hep3B) beta-catenin mutations. Transfection of HepG2 and Hep3B cells with human beta-catenin (CTNNB1) small interfering RNA resulted in a significant beta-catenin decrease, as confirmed by Western blot analyses and immunofluorescence, also leading to decreased expression of known target genes such as cyclin D1 and glutamine synthetase. The decrease in beta-catenin activity was confirmed by TOPflash reporter luciferase assay. The functional impact of diminished beta-catenin was exhibited as temporal decrease in tumor cell viability by the MTT assay. A concomitant decrease in tumor cell proliferation was also evident with [(3)H]thymidine incorporation and verified with soft agar assays. Thus, beta-catenin is essential for the survival and growth of hepatoma cells independent of mutations in the beta-catenin gene and provide a proof of principle for the significance of the therapeutic inhibition of beta-catenin in HCC.

SDX-308 and SDX-101, Non-Steroidal Anti-Inflammatory Drugs, as Therapeutic Candidates for Treating Hematologic Malignancies Including Myeloma

Non-steroidal anti-inflammatory drugs have been shown to inhibit carcinogenesis in colon cancer, and to induce apoptosis in a variety of tumor cell lines. Some anti-tumor effects are thought to be related to their cyclooxygenase-2-inhibitory activity, but recent studies have shown that non-steroidal anti-inflammatory drugs exert their anti-tumor effect via cyclooxygenase-2-independent mechanism. SDX-308 (CEP-18082) is a non-cyclooxygenase-2-inhibiting indole-pyran analog and is structurally related to SDX-101, an R-enantiomer of etodolac. SDX-308 has a potent anti-myeloma effect and shows synergism in combination with other drugs for the treatment of chronic lymphocytic leukemia. In addition SDX-308 inhibits osteoclast formation and activity and thereby might be an attractive drug for the treatment of diseases with increased osteoclast activity such as osteolytic lesions in multiple myeloma and metastatic carcinomas, as well as osteoporosis. This review covers future application of SDX-308 as an anti-myeloma drug regulating increased osteoclast activity.