Targeting the EGFR, VEGFR, and PDGFR on colon cancer cells and stromal cells is required for therapy

Repurposing celecoxib for colorectal cancer targeting via pH-triggered ultra-elastic nanovesicles: Pronounced efficacy through up-regulation of Wnt/β-catenin pathway in DMH-induced tumorigenesis

Celecoxib (CLX), a selective inhibitor for cyclooxygenase 2 (COX-2), has manifested potential activity against diverse types of cancer. However, low bioavailability and cardiovascular side effects remain the major challenges that limit its exploitation. In this work, we developed ultra-elastic nanovesicles (UENVs) with pH-triggered surface charge reversal traits that could efficiently deliver CLX to colorectal segments for snowballed tumor targeting. CLX-UENVs were fabricated via a thin-film hydration approach. The impact of formulation factors (Span 80, Tween 80, and sonication time) on the nanovesicular features was evaluated using Box-Behnken design, and the optimal formulation was computed. The optimum formulation was positively coated with polyethyleneimine (CLX-PEI-UENVs) and then coated with Eudragit S100 (CLX-ES-PEI-UENVs). The activity of the optimized nano-cargo was explored in 1,2-dimethylhydrazine-induced colorectal cancer in Wistar rats. Levels of COX-2, Wnt-2 and β-catenin were assessed in rats' colon. The diameter of the optimized CLX-ES-PEI-UENVs formulation was 253.62 nm, with a zeta potential of -23.24 mV, 85.64% entrapment, and 87.20% cumulative release (24 h). ES coating hindered the rapid release of CLX under acidic milieu (stomach and early small intestine) and showed extended release in the colon section. In colonic environments, the ES coating layer was removed due to high pH, and the charge on the nanovesicular corona was shifted from negative to positive. Besides, a pharmacokinetics study revealed that CLX-ES-PEI-UENVs had superior oral bioavailability by 2.13-fold compared with CLX suspension. Collectively, these findings implied that CLX-ES-PEI-UENVs could be a promising colorectal-targeted nanoplatform for effective tumor management through up-regulation of the Wnt/β-catenin pathway.

Potential therapeutic targets of the JAK2/STAT3 signaling pathway in triple-negative breast cancer

Triple-negative breast cancer (TNBC) poses a significant clinical challenge due to its propensity for metastasis and poor prognosis. TNBC evades the body's immune system recognition and attack through various mechanisms, including the Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. This pathway, characterized by heightened activity in numerous solid tumors, exhibits pronounced activation in specific TNBC subtypes. Consequently, targeting the JAK2/STAT3 signaling pathway emerges as a promising and precise therapeutic strategy for TNBC. The signal transduction cascade of the JAK2/STAT3 pathway predominantly involves receptor tyrosine kinases, the tyrosine kinase JAK2, and the transcription factor STAT3. Ongoing preclinical studies and clinical research are actively investigating this pathway as a potential therapeutic target for TNBC treatment. This article comprehensively reviews preclinical and clinical investigations into TNBC treatment by targeting the JAK2/STAT3 signaling pathway using small molecule compounds. The review explores the role of the JAK2/STAT3 pathway in TNBC therapeutics, evaluating the benefits and limitations of active inhibitors and proteolysis-targeting chimeras in TNBC treatment. The aim is to facilitate the development of novel small-molecule compounds that target TNBC effectively. Ultimately, this work seeks to contribute to enhancing therapeutic efficacy for patients with TNBC.

Imatinib exhibit synergistic pleiotropy in the prevention of colorectal cancer by suppressing proinflammatory, cell survival and angiogenic signaling

Recent global incidences and mortality rates have placed colorectal cancer (CRC) at third and second positions, respectively, among both sexes of all ages. Resistance during chemotherapy is a big problem in the treatment and disease-free survival of CRC patients. Discovery of new anticancer drug(s) is a time taking process and therefore, invites studies for repurposing the known therapeutics. The present study was conceived to analyze the anticancer role of Imatinib in experimental CRC at early stages. Different experimental procedures e.g. tumor incidences or histoarchitectural changes, gene and protein expression analysis, estimations of intracellular calcium, ROS, mitochondrial membrane potential, apoptotic index and molecular docking was performed to support the hypothesis. It was observed that Imatinib could function as an immunomodulator by breaking the feed-back loop between the proinflammatory cytokines (IL-1β and TNF-α) and transcription factors (NF-κB, Jak3/Stat3) knowingly involved in increased cell proliferation during tumorigenesis via activating different intracellular signaling. Also, Imatinib could independently deregulate the other cell survival and proliferation signaling e.g. PI3-K/Akt/mTOR, Wnt/β-catenin and MAPK. Proinflammatory cytokines orchestrated intracellular signaling also involve angiogenic factors to be upregulated during CRC which were also seemed to be independently suppressed by Imatinib. Restoration of physiological apoptosis by increasing the release of intracellular calcium to generate ROS thereby reducing the mitochondrial membrane potential for the release of cytochrome c and activation of caspase-3 was also reported with Imatinib administration. Thus, it may be suggested that Imatinib show synergistic pleiotropy in suppressing the interlinked tumorigenic signaling pathways independently.

CRISPR-mediated ablation of overexpressed EGFR in combination with sunitinib significantly suppresses renal cell carcinoma proliferation

Receptor tyrosine kinases, such as VEGFR, PDGFR and EGFR, play important roles in renal cancer. In this study, we investigated EGFR knockout as a therapeutic approach in renal cell carcinoma (RCC). We showed that a renal cell carcinoma cell line (RC21) has higher expression of EGFR as compared to other frequently used cell lines such as HEK293, A549, Hela and DLD1. Ablation of EGFR by CRISPR/Cas9 significantly restrained tumor cell growth and activated the MAPK (pERK1/2) pathway. The VEGFR and PDGFR inhibitor, sunitinib, attenuated the expression of MAPK (pERK1/2) and pAKT induced by EGFR loss and further inhibited EGFR-/- cell proliferation. We showed that loss of EGFR eventually leads to resistance to SAHA and cisplatin. Furthermore, EGFR loss induced G2/M phase arrest and resulted in an increased resistance to TNF-related apoptosis-inducing ligand (TRAIL) in renal cell carcinoma. Thus, ablation of overexpressed EGFR by CRISPR/Cas9 alone or in combination with sunitinib may be a new treatment option for renal cell carcinoma.

Study of the antitumor mechanisms of apiole derivatives (AP-02) from Petroselinum crispum through induction of G0/G1 phase cell cycle arrest in human COLO 205 cancer cells

Background

Apiole was isolated from the leaves of various plants and vegetables and has been demonstrated to inhibit human colon cancer cell (COLO 205 cells) growth through induction of G0/G1 cell cycle arrest and apoptotic cell death. This study further explored the antitumor effects of apiole derivatives AP-02, 04, and 05 in COLO 205 cancer cells.

Methods

Human breast (MDA-MB-231, ZR75), lung (A549, PE089), colon (COLO 205, HT 29), and hepatocellular (Hep G2, Hep 3B) cancer cells were treated with apiole and its derivatives in a dose-dependent manner. Flow cytometry analysis was subsequently performed to determine the mechanism of AP-02-induced G0/G1 cell cycle arrest. The in vivo antitumor effect of AP-02 (1 and 5 mg/kg, administered twice per week) was examined by treating athymic nude mice bearing COLO 205 tumor xenografts. The molecular mechanisms of AP-02-induced antitumor effects were determined using western blot analysis.

Results

AP-02 was the most effective compound, especially for inhibition of COLO 205 colon cancer cell growth. The cytotoxicity of AP-02 in normal colon epithelial (FHC) cells was significantly lower than that in other normal cells derived from the breast, lung or liver. Flow cytometry analysis indicated that AP-02-induced G0/G1 cell cycle arrest in COLO 205 cells but not in HT 29 cells (< 5 μM for 24 h, **p < 0.01). Tumor growth volume was also significantly inhibited in AP-02 (> 1 mg/kg)-treated athymic nude mice bearing COLO 205 tumor xenografts compared to control mice (*p < 0.05). Furthermore, G0/G1 phase regulatory proteins (p53 and p21/Cip1) and an invasion suppressor protein (E-cadherin) were significantly upregulated, while cyclin D1 was significantly downregulated, in AP-02-treated tumor tissues compared to the control group (> 1 mg/kg, *p < 0.05).

Conclusions

Our results provide in vitro and in vivo molecular evidence of AP-02-induced anti-proliferative effects on colon cancer, indicating that this compound might have potential clinical applications.

Electronic supplementary material

The online version of this article (10.1186/s12906-019-2590-9) contains supplementary material, which is available to authorized users.

Development of the LYVE-1 gene with an acidic-amino-acid-rich (AAAR) domain in evolution is associated with acquisition of lymph nodes and efficient adaptive immunity

CRSBP-1 (mammalian LYVE-1) is a membrane glycoprotein highly expressed in lymphatic endothelial cells (LECs). It has multiple ligands, including hyaluronic acid (HA) and growth factors/cytokines (e.g., PDGF-BB and VEGF-A) containing CRS motifs (clusters of basic amino-acid residues). The ligand binding activities are mediated by Link module and acidic-amino-acid-rich (AAAR) domains, respectively. These CRSBP-1/LYVE-1 ligands have been shown to induce opening of lymphatic intercellular junctions in LEC monolayers and in lymphatic vessels in wild-type mice. We hypothesize that CRSBP-1/LYVE-1 ligands, particularly CRS-containing growth factors/cytokines, are secreted by immune and cancer cells for lymphatic entry during adaptive immune responses and lymphatic metastasis. We have looked into the origin of the Link module and AAAR domain of LYVE-1 in evolution and its association with the development of lymph nodes and efficient adaptive immunity. Lymph nodes represent the only major recent innovation of the adaptive immune systems in evolution particularly to mammals and bird. Here we demonstrate that the development of the LYVE-1 gene with the AAAR domain in evolution is associated with acquisition of lymph nodes and adaptive immunity. LYVE-1 from other species, which have no lymph nodes, lack the AAAR domain and efficient adaptive immunity. Synthetic CRSBP-1 ligands PDGF and VEGF peptides, which contain the CRS motifs of PDGF-BB and VEGF-A, respectively, specifically bind to CRSBP-1 but do not interact with either PDGFβR or VEGFR2. These peptides function as adjuvants by enhancing adaptive immunity of pseudorabies virus (PRV) vaccine in pigs. These results support the notion that LYVE-1 is involved in adaptive immunity in mammals.

Potential of Cationic-Polymeric Nanoparticles for Oral Delivery of Naringenin: In Vitro and In Vivo Investigations

The objective of the study was to improve the bioavailability and anticancer potential of naringenin (NRG) by developing a drug-loaded polymeric nanodelivery system. NRG-loaded eudragit E100 nanoparticle (NRG-EE100-NPs) system was developed and physicochemically characterized. In vivo pharmacokinetic and in vitro cytotoxicity abilities of the NRG-EE100-NPs were investigated. In vivo anticancer activity was evaluated in murine BALB/c mice-bearing colorectal tumor. The NRG-EE100-NPs had an optimum mean particle size (430.42 ± 5.78 nm), polydispersity index (0.283 ± 0.089) with percent entrapment efficiency (68.83 ± 3.45%). The NRG-EE100-NPs demonstrated significant higher bioavailability (∼96-fold; p <0.05) as well as cytotoxicity (∼16-fold; p <0.001) as compared to free NRG. Furthermore, NRG-EE100-NPs indicated significant tumor suppression (p <0.01) subsequently improvement in survival rate compared to free NRG in vivo. Thus, the physicochemical properties and colorectal cancer efficacy of NRG were improved by successful encapsulating in cationic-polymeric nanoparticle system.

The stromal genome heterogeneity between breast and prostate tumors revealed by a comparative transcriptomic analysis

Stromal microenvironment increases tumor cell survival, proliferation and migration, and promotes angiogenesis. In order to provide comprehensive information on the stromal heterogeneity of diverse tumors, here we employed the microarray datasets of human invasive breast and prostate cancer-associated stromals and applied Gene Set Enrichment Analysis (GSEA) to compare the gene expression profiles between them. As a result, 8 up-regulated pathways and 73 down-regulated pathways were identified in the breast tumor stroma, while 32 up-regulated pathways and 18 down-regulated pathways were identified in the prostate tumor stroma. Only 9 pathways such as tryptophan metabolism were commonly up or down regulated, but most of them (including ABC transporters) were specific for these two tumors. Several essential tumors stromal marker genes were also significantly identified. For example, CDH3 was significantly up-regulated in the stromals of both breast and prostate tumors, however EGFR was only significantly down-regulated in the stromal of breast tumor. Our study would be helpful for future therapeutic and predictive applications in breast and prostate cancers.

Quantitative assessment of short amplicons in FFPE-derived long-chain RNA

Formalin-fixed paraffin-embedded (FFPE) tissues are important resources for molecular medical research. However, long-chain RNA analysis is restricted in FFPE tissues due to high levels of degradation. To explore the possibility of long RNA quantification in FFPE tissues, we selected 14 target RNAs (8 mRNAs and 6 long noncoding RNAs) from literatures, and designed short (~60 bp) and long (~200 bp) amplicons for each of them. Colorectal carcinomas with adjacent normal tissues were subjected to quantitative reverse-transcription PCR (quantitative RT-PCR) in 3 cohorts, including 18 snap-frozen and 83 FFPE tissues. We found that short amplicons were amplified more efficiently than long amplicons both in snap-frozen (P = 0.0006) and FFPE (P = 0.0152) tissues. Nonetheless, comparison of colorectal carcinomas with their adjacent normal tissues demonstrated that the consistency of fold-change trends in a single short amplicon between snap-frozen and FFPE tissues was only 36%. Therefore, we innovatively performed quantitative RT-PCR with 3 non-overlapping short amplicons for 14 target RNAs in FFPE tissues. All target RNAs showed a concordance of 100% of fold-change trends in at least two short amplicons, which offers sufficient information for accurate quantification of target RNAs. Our findings demonstrated the possibility of long-chain RNA analysis with 3 non-overlapping short amplicons in standardized-preserved FFPE tissues.

Screening of hub genes and pathways in colorectal cancer with microarray technology

Here we intend to identify key genes and pathways in the pathogenesis of colorectal cancer (CRC) through analyzing microarray data with bioinformatic tools. The gene expression profile dataset GSE23878 was downloaded from Gene Expression Omnibus and differentially expressed genes (DEGs) were screened out using Student's t-test. GO function and KEGG pathway enrichment analyses were performed for these DEGs with the DAVID online tool. Interaction network was constructed among the over-represented pathways based on the protein-protein interactions within the pathways. Besides, the protein interaction information obtained from HPRD database were applied to constructed protein-protein interaction networks among the DEGs and hub genes and function module were screened out. A total of 2,296 DEGs were obtained and they were enriched in 34 pathways. An interaction network was constructed among 32 pathways, in which p53 signaling pathway acted as the hub pathway as it showed the highest node degree. The protein-protein interaction network comprised 1,481 interaction relationships among 332 genes which included 40 DEGs. Further analysis revealed that theses DEGs formed 7 function modules and many genes, such as PDGFRB, MET, FZD2, CCND1, PRKCB, ARHGEF6, JUP, WNT2, WNT5A and WNT11 were key genes in the networks. The DEGs and disturbed biological functions uncovered in present study may play important roles in the development of CRC and can contribute to the understanding on molecular mechanisms of CRC. Further these DEGs we obtained can be acted as potential biomarkers for diagnosis and therapy of CRC.

Preparation and characterization of nano-liposome-mediated FL gene in the Lovo cells

AIMS

The purpose of the present work was to formulate and evaluate cationic nano-liposomes as novel nonviral gene delivery for colon cancer treatment.

METHODS

Recombinant pEGFP-c1-Fms-like tyrosine kinase receptor 3 ligand (FL) plasmids containing human FL gene and green fluorescent protein (GFP) reporter genes were constructed. FL and GFP Gene-carrying cationic nano-liposomes were prepared based on the electrostatic adherence principle and then transfected into Lovo cells. The morphology, particle size, and zeta potential of gene-carrying cationic nano-liposomes were observed using an electron microscope. GFP expression was observed by fluorescence microscopy to assay the transfection efficiency. The cytotoxicity of FL/nano-liposomes was evaluated by the MTT method.

RESULTS

Recombinant plasmids pEGFP-c1-FL are successfully constructed using gene cloning methods and confirmed by restriction enzyme digestion and sequencing. The cationic nano-liposomes carrying pEGFP-cl-FL were observed by an electron micrograph and showed uniform spherical or elliptical shapes and many pores. The fluorescence microscopy images of gene-carrying cationic nano-liposomes showed good expression of GFP in pEGFP and pEGFP-cl-FL groups. The MTT assay of cell death indicated a significantly higher level of cell death between the FL group and the control group at 24, 48, and 96 hours after transplantation.

CONCLUSION

Cationic nano-liposomes show safe and high-performance transfection as gene carriers. Gene therapy has significant implications for colon cancer treatment in future.

MiR-222 modulates multidrug resistance in human colorectal carcinoma by down-regulating ADAM-17

Colorectal carcinoma is a frequent cause of cancer-related death in men and women throughout the world. MicroRNAs are endogenous small noncoding RNAs that negatively regulate gene expression at the posttranscriptional level. We investigated the role of ADAM-17 (a desintegrin and metalloproteases 17) as a novel multidrug resistance (MDR) mechanism in multidrug-resistant colorectal carcinoma (CRC) and the role of miR-222 in the development of MDR in CRC cells. We found that the high expression of ADAM-17, which results in growth factor shedding and growth factor receptor activation could induce drug resistance in CRC. Pharmacological inhibition of ADAM-17, in conjunction with chemotherapy, may have therapeutic potential for the treatment of CRC. ADAM-17 is a predicted target of miR-222, which was downregulated in multidrug-resistant CRC cells. The presence of miR-222 was consistently inversely proportionate to the expression levels of ADAM-17. We found that elevated levels of miR-222 in the mimics-transfected HCT116/L-OHP and HCT-8/VCR cells reduced the ADAM-17 protein level and the luciferase activity of an ADAM-17 3' untranslated region-based reporter and sensitized these cells' apoptosis to some anticancer drugs. Our findings suggest that miR-222 could play a role in the development of MDR by modulation of ADAM-17, the new MDR treatment target in colorectal carcinoma cells.

CCL5 neutralization restricts cancer growth and potentiates the targeting of PDGFRβ in colorectal carcinoma

Increased CCL5 levels are markers of an unfavourable outcome in patients with melanoma, breast, cervical, prostate, gastric or pancreatic cancer. Here, we have assessed the role played by CCL5/CCR5 interactions in the development of colon cancer. To do so, we have examined a number of human colorectal carcinoma clinical specimens and found CCL5 and its receptors over-expressed within primary as well as liver and pulmonary metastases of patients compared to healthy tissues. In vitro, CCL5 increased the growth and migratory responses of colon cancer cells from both human and mouse origins. In addition, systemic treatment of mice with CCL5-directed antibodies reduced the extent of development of subcutaneous colon tumors, of liver metastases and of peritoneal carcinosis. Consistently, we found increased numbers of CD45-immunoreactive cells within the stroma of the remaining lesions as well as at the interface with the healthy tissue. In contrast, selective targeting of CCR5 through administration of TAK-779, a CCR5 antagonist, only partially compromised colon cancer progression. Furthermore, CCL5 neutralization rendered the tumors more sensitive to a PDGFRβ-directed strategy in mice, this combination regimen offering the greatest protection against liver metastases and suppressing macroscopic peritoneal carcinosis. Collectively, our data demonstrate the involvement of CCL5 in the pathogenesis of colorectal carcinoma and point to its potential value as a therapeutic target.

Vascular endothelial growth factor receptors and the therapeutic targeting of angiogenesis in cancer: where do we go from here?

Abstract Vascular Endothelial Growth Factor receptors (VEGFRs), the interactions with their ligands and the subsequent signalling pathways are known to play a vital role in tumour angiogenesis. Initial clinical trials of VEGFR inhibitors were disappointing but over the past decade some therapies have been successfully brought to market. At present, VEGFR inhibitors appear to be most promising as adjuvants to conventional chemotherapy. However, several interacting signalling molecules and downstream pathways have recently been shown to interact with VEGFR signalling and provide promising novel targets, such as the platelet-derived growth factor (PDGF), epithelial growth factor (EGF), human epithelial receptor-2, (HER-2) Tie-2 and oestrogen receptors. Elucidation of this web of signalling pathways may identify new therapeutic strategies which may be used in combination with VEGFR inhibitors to augment the efficacy of anti-angiogenic cancer treatments. This review assesses the role of modulating VEGFR activity in cancer and systematically examines current evidence and trials in this area.

Genomic analysis identifies unique signatures predictive of brain, lung, and liver relapse

The ability to predict metastatic potential could be of great clinical importance, however, it is uncertain if predicting metastasis to specific vital organs is feasible. As a first step in evaluating metastatic predictions, we analyzed multiple primary tumors and metastasis pairs and determined that >90% of 298 gene expression signatures were found to be similarly expressed between matched pairs of tumors and metastases; therefore, primary tumors may be a good predictor of metastatic propensity. Next, using a dataset of >1,000 human breast tumor gene expression microarrays we determined that HER2-enriched subtype tumors aggressively spread to the liver, while basal-like and claudin-low subtypes colonize the brain and lung. Correspondingly, brain and lung metastasis signatures, along with embryonic stem cell, tumor initiating cell, and hypoxia signatures, were also strongly expressed in the basal-like and claudin-low tumors. Interestingly, low “Differentiation Scores,” or high expression of the aforementioned signatures, further predicted for brain and lung metastases. In total, these data identify that depending upon the organ of relapse, a combination of gene expression signatures most accurately predicts metastatic behavior.

Inhibition of Anchorage-Independent Proliferation and G0/G1 Cell-Cycle Regulation in Human Colorectal Carcinoma Cells by 4,7-Dimethoxy-5-Methyl-l,3-Benzodioxole Isolated from the Fruiting Body of Antrodia camphorate

In this study, 4,7-dimethoxy-5-methyl-l,3-benzodioxole (SY-1) was isolated from three different sources of dried fruiting bodies of Antrodia camphorate (AC). AC is a medicinal mushroom that grows on the inner heartwood wall of Cinnamomum kanehirai Hay (Lauraceae), an endemic species that is used in Chinese medicine for its anti-tumor and immunomodulatory properties. In this study, we demonstrated that SY-1 profoundly decreased the proliferation of human colon cancer cells (COLO 205) through G0/G1 cell-cycle arrest (50–150 μM) and induction of apoptosis (>150 μM). Cell-cycle arrest induced by SY-1 was associated with a significant increase in levels of p53, p21/Cip1 and p27/Kip1, and a decrease in cyclins D1, D3 and A. In contrast, SY-1 treatment did not induce significant changes in G0/G1 phase cell-cycle regulatory proteins in normal human colonic epithelial cells (FHC). The cells were cultured in soft agar to evaluate anchorage-independent colony formation, and we found that the number of transformed colonies was significantly reduced in the SY-1-treated COLO 205 cells. These findings demonstrate for the first time that SY-1 inhibits human colon cancer cell proliferation through inhibition of cell growth and anchorage-independent colony formation in soft agar. However, the detailed mechanisms of these processes remain unclear and will require further investigation.

Study of the Anti-Proliferative Activity of 5-Substituted 4,7-Dimethoxy-1,3-Benzodioxole Derivatives of SY-1 from Antrodia camphorata on Human COLO 205 Colon Cancer Cells

A set of 10 4,7-dimethoxy-1,3-benzodioxole derivatives based on a lead compound previously discovered by our group, SY-1, which was isolated from Antrodia camphorata, were evaluated for their in vitro inhibitory activity on human colorectal carcinoma cells (COLO 205). Structure-activity relationship studies of the 10 compounds indicated the importance of the chain length of the alkyl group at the 5-position, and the 2-propenyl substituent named “apiole” exhibited the most potent inhibitory activity. In the present study, we demonstrate that the SY-1 analogue “apiole” decreased the proliferation of COLO 205 cells, but not that of normal human colonic epithelial cells (FHC). The G0/G1 cell cycle arrest induced by apiole (75–225 μM) was associated with significantly increased levels of p53, p21 and p27 and decreased levels of cyclin D1. Concerning COLO 205 cell apoptosis, apiole (>150 μM) treatment significantly increased the levels of cleaved caspases 3, 8, 9 and bax/bcl-2 ratio and induced ladder formation in DNA fragmentation assay and sub-G1 peak in flow cytometry analysis. These findings suggest that apiole can suppress COLO 205 cell growth; however, the detailed mechanisms of these processes require further investigation.

Chemotherapy-induced activation of ADAM-17: a novel mechanism of drug resistance in colorectal cancer

PURPOSE

We have shown previously that exposure to anticancer drugs can trigger the activation of human epidermal receptor survival pathways in colorectal cancer (CRC). In this study, we examined the role of ADAMs (a disintegrin and metalloproteinases) and soluble growth factors in this acute drug resistance mechanism.

EXPERIMENTAL DESIGN

In vitro and in vivo models of CRC were assessed. ADAM-17 activity was measured using a fluorometric assay. Ligand shedding was assessed by ELISA or Western blotting. Apoptosis was assessed by flow cytometry and Western blotting.

RESULTS

Chemotherapy (5-fluorouracil) treatment resulted in acute increases in transforming growth factor-alpha, amphiregulin, and heregulin ligand shedding in vitro and in vivo that correlated with significantly increased ADAM-17 activity. Small interfering RNA-mediated silencing and pharmacologic inhibition confirmed that ADAM-17 was the principal ADAM involved in this prosurvival response. Furthermore, overexpression of ADAM-17 significantly decreased the effect of chemotherapy on tumor growth and apoptosis. Mechanistically, we found that ADAM-17 not only regulated phosphorylation of human epidermal receptors but also increased the activity of a number of other growth factor receptors, such as insulin-like growth factor-I receptor and vascular endothelial growth factor receptor.

CONCLUSIONS

Chemotherapy acutely activates ADAM-17, which results in growth factor shedding, growth factor receptor activation, and drug resistance in CRC tumors. Thus, pharmacologic inhibition of ADAM-17 in conjunction with chemotherapy may have therapeutic potential for the treatment of CRC.

ADAM-17: a target to increase chemotherapeutic efficacy in colorectal cancer?

Chemotherapy-induced activation of ADAM-17 results in increased growth factor shedding and activation of growth factor receptor-mediated pro-survival response. Enhanced ADAM-17 activity and HER ligand shedding results in resistance to chemotherapy in CRC. Therapies that decrease ADAM-17 activity in conjunction with current treatments may enhance response rates in advanced CRC patients.

AEE788 is a vascular endothelial growth factor receptor tyrosine kinase inhibitor with antiproliferative and proapoptotic effects in acute myeloid leukemia

OBJECTIVE

Aberrant activation of tyrosine kinase receptors is frequently observed in acute myelogenous leukemia (AML). Moreover, activating mutations of the fms-like tyrosine kinase 3 (FLT3) receptor can be found in approximately 30% of patients, thereby representing one of the most frequent single genetic alterations in AML. AEE788, a novel dual receptor tyrosine kinase inhibitor of endothelial growth factor and vascular endothelial growth factor (VEGF), is being studied in several solid tumors with remarkable success. It is not known, however, about the efficacy of this inhibitor in the treatment of AML. Therefore, we investigated the effect of AEE788 in the treatment of three human AML cell lines and seven AML patient samples.

MATERIALS AND METHODS

Cell survival in THP-1, MOLM-13, and MV4-11 cell lines (the two last harboring the FLT3/internal tandem duplication mutation) and AML blasts incubated with 0.5 to 15 microM AEE788 were quantified. We also studied the activation of VEGF/VEGF receptors loop, FLT3, and their downstream effectors (Akt, extracellular signal-regulated kinase, signal transducers and activators of transcription 5, and nuclear factor-kappaB).

RESULTS

Our data showed that AEE788 was a tyrosine kinase inhibitor of FLT3 activity and had antiproliferative and proapoptotic activity in AML-derived cell lines and AML blasts that presented phosphorylation of the FLT3 receptor. Consistently, in these cells AEE788 abrogated VEGF/VEGF receptors activation and the survival signaling pathways studied.

CONCLUSION

Taken together, the activity of AEE788 might represent a promising new option of targeting FLT3 for the treatment of AML.

Epidermal growth factor in clinical practice - a review of its biological actions, clinical indications and safety implications

Chemotaxis, mitogenesis, motogenesis and cytoprotection are common cellular events involved in both tumourigenesis and tissue repair, which appear amplified upon growth factors exposure. Epidermal growth factor (EGF) promotes these events in epithelial and mesenchymal cells through the binding to a specific tyrosine kinase receptor. In experimental oncology settings, EGF does not initiate malignant transformation but exhibits 'tumour promotion'. These observations have raised doubts on the clinical use of EGF despite solid demonstrations of efficacy in experimental conditions and clinical trials. The results of a Pubmed and Bioline investigation on EGF clinical uses and preclinical safety data are presented here. EGF topical administration has been used since 1989 to enhance the healing process of a variety of peripheral tissues wounds (16 clinical reports), as well as its intravenous, oral and rectal administration for gastrointestinal damages (11 clinical reports). EGF therapeutic efficacy and excellent tolerability seem demonstrated. Lack of long-term adverse effects is highlighted in those studies with 6, 12 and 24 months of patients follow-up. Although post-treatment follow-up may fall short for malignant growth, there are no reports on evidences linking EGF clinical use with cancer. A multicentre, nationwide survey in Cuba, 15 years after randomly using silver sulphadiazine with EGF or not in burn victims yielded that cancer incidence was comparable between EGF-treated and control subjects and that such incidence rate does not differ from the age-matched national incidence for those 15-year period. All the animal species subjected to long-term EGF systemic administration exhibit dose-dependent and reversible epithelial organs hyperplasia with no changes in cells phenotypic differentiation. Histotypic pre-malignant markers were not identified. The results emerged from co-carcinogenesis studies and from transgenic mice over-expressing EGF are conflicting and indicate that EGF overexposure, either innate or postnatal, may not be sufficient to transform cells. The ability of EGF to heal injured tissues in life-threatening scenarios or to assist in preventing physical and social disability advocates for its clinical use under a rational medical risk/benefit balance.

The anti-proliferative side effects of AEE788, a tyrosine kinase inhibitor blocking both EGF- and VEGF-receptor, are liver-size-dependent after partial hepatectomy in rats

BACKGROUND

Blocking of EGFR signaling by the tyrosine kinase inhibitor AEE788 was well tolerated and did not inhibit liver regeneration after standard 70% partial hepatectomy (PH) in a rat model, as demonstrated previously. However, serum levels of AEE788 at POW1 were 3-fold higher than in the non-resected control group. Therefore, we expanded theses studies to a model of extended 90%PH to investigate the role of liver size for the metabolism of AEE788 and its potential influence on side effects, liver regeneration and liver remodeling.

METHOD

Rats treated with 50 mg/kg AEE788 or solvent every other day orally were subjected to 90%PH. Animals were sacrificed at 1, 2, 7 and 28 days after PH. We measured plasma and liver levels of AEE788 and assessed anti-proliferative side effects, liver regeneration, and liver architecture.

RESULT

Liver regeneration and liver architecture were not impaired by AEE788 treatment after 90%PH. 90%PH caused a clinically relevant drug accumulation within 1 week of treatment (AEE788 serum and tissue levels: 90%PH*>70%PH*>normal control, *p < 0.05), suggesting a liver-size-dependent metabolism of the drug. Drug accumulation after 90%PH was associated with severe side effects (delayed body weight recovery, diarrhea, impaired hair growth) within 1 week of treatment.

CONCLUSION

Treatment with AEE788 could be a potential strategy for adjuvant treatment after oncological liver resection, as liver regeneration was not impaired. Our results suggest a liver-size-dependent metabolism of AEE788 leading to drug accumulation and subsequently to severe side effects. It calls for therapeutic drug monitoring in the early postoperative phase after extended resection.

Effect of AEE788 and/or Celecoxib on colon cancer cell morphology using advanced microscopic techniques

Analysis of changes in cancer cell morphology and cytoskeletal element induced by external stimuli is focus of current cancer chemotherapeutic studies. Cancer cell cytoskeleton is complex network of interwoven protein fibers composed of microtubules, microfilaments and intermediate filaments. These interwoven protein fibers are responsible for maintaining cell morphology, movement, adhesion and transmembrane signal transmission. In this study, morphological and cytoskeletal changes induced by AEE788 and/or Celecoxib on colon cancer cell HCT 15 were analyzed using advanced microscopic techniques. Cell proliferation assay was used for determining IC(50) of AEE788 and/or Celecoxib on HCT 15. Confocal microscopic analysis of AEE788 and/or Celecoxib treated HCT 15 was performed using Rhodamine-Phalloidin (actin stain) and Hoechst 33342 (nuclear stain). Atomic force (AFM) and scanning electron microscopic (SEM) studies were also performed to analyze cell morphology and cell wall extension (filopodia and lamellipodia). In addition, quantitative analysis of morphological parameters was studied using cellular image processing technique. This is the first report that combination of AEE788 and Celecoxib additively increase growth inhibition and cell death on human colon cancer cell HCT 15 as estimated by cell proliferation assay. Morphological analysis of AEE788 or Celecoxib treated HCT 15 cell for 24h have not revealed significant change in morphology under phase contrast microscopy. But, slight morphological changes were observed in combination (AEE788+Celecoxib) treated HCT 15 for 24h. In contrast, high resolution confocal laser fluorescence and atomic force microscopic studies have revealed cell shrinkage, disorganized actin filament and, loss of filopodia and lamellipodia. These changes were more prominent in combination of AEE788 and Celecoxib treated HCT 15 than either drug alone. These results may suggest antiproliferative and antimetastatic activity of AEE788 and/or Celecoxib. Quantitative analysis of morphological parameters using cellular image processing technique have shown decrease in mean area, perimeter, compactness and eccentricity of combination drug treated cells than either drug alone. These results further support the confocal and AFM study. Scanning electron microscopic study of AEE788 and/or Celecoxib treated HCT 15 has also shown morphological changes and loss of filopodia and lamellipodia. In conclusion, this investigation of morphological and cytoskeletal changes using advanced microscopic techniques present a significant foundation for evaluating anticancer activity of a drug and form a new strategy for evaluating effect of AEE788 and/or Celecoxib on colon cancer.

Identification of tyrosine-phosphorylated proteins associated with metastasis and functional analysis of FER in human hepatocellular carcinoma cells

BACKGROUND

Aberrant activity of tyrosine-phosphorylated proteins is commonly associated with HCC metastasis. Cell signaling events driven by these proteins are implicated in numerous processes that alter cancer cell behavior. Exploring the activities and signaling pathways of these proteins in HCC metastasis may help in identifying new candidate molecules for HCC-targeted therapy.

METHODS

Hep3B (a nonmetastatic HCC cell line) and MHCC97H (a highly metastatic HCC cell line) were used in this study, and the tyrosine-phosphorylated proteins expressed in these cell lines were profiled by a phosphoproteomics technique based on LC-MS/MS. Protein-protein interaction and functional clustering analyses were performed to determine the activities of the identified proteins and the signaling pathways closely related to HCC metastasis.

RESULTS

In both cell lines, a total of 247 phosphotyrosine (pTyr) proteins containing 281 pTyr sites were identified without any stimulation. The involvement of almost 30% of these in liver or liver cancer has not been reported previously. Biological process clustering analysis indicated that pTyr proteins involved in cell motility, migration, protein autophosphorylation, cell-cell communication, and antiapoptosis functions were overexpressed during metastasis. Pathway clustering analysis revealed that signaling pathways such as those involved in EGFR signaling, cytokine- and chemokine-mediated signal transduction, and the PI3K and JAK-STAT cascades were significantly activated during HCC metastasis. Moreover, noncanonical regulation of the JNK cascade might also provide new targets for HCC metastasis. After comparing the pTyr proteins that were differentially expressed during HCC cell metastasis, we selected FER, a nonreceptor tyrosine kinase, and validated its role in terms of both expression and function. The data confirmed that FER might play a critical role in the invasion and metastasis of HCC.

CONCLUSION

The identification of pTyr proteins and signaling pathways associated with HCC metastasis could provide useful information for selecting new molecular intervention targets. Moreover, FER might serve as a novel drug target in future HCC therapy.

Combining the receptor tyrosine kinase inhibitor AEE788 and the mammalian target of rapamycin (mTOR) inhibitor RAD001 strongly inhibits adhesion and growth of renal cell carcinoma cells

BACKGROUND

Treatment options for metastatic renal cell carcinoma (RCC) are limited due to resistance to chemo- and radiotherapy. The development of small-molecule multikinase inhibitors has now opened novel treatment options. We evaluated the influence of the receptor tyrosine kinase inhibitor AEE788, applied alone or combined with the mammalian target of rapamycin (mTOR) inhibitor RAD001, on RCC cell adhesion and proliferation in vitro.

METHODS

RCC cell lines Caki-1, KTC-26 or A498 were treated with various concentrations of RAD001 or AEE788 and tumor cell proliferation, tumor cell adhesion to vascular endothelial cells or to immobilized extracellular matrix proteins (laminin, collagen, fibronectin) evaluated. The anti-tumoral potential of RAD001 combined with AEE788 was also investigated. Both, asynchronous and synchronized cell cultures were used to subsequently analyze drug induced cell cycle manipulation. Analysis of cell cycle regulating proteins was done by western blotting.

RESULTS

RAD001 or AEE788 reduced adhesion of RCC cell lines to vascular endothelium and diminished RCC cell binding to immobilized laminin or collagen. Both drugs blocked RCC cell growth, impaired cell cycle progression and altered the expression level of the cell cycle regulating proteins cdk2, cdk4, cyclin D1, cyclin E and p27. The combination of AEE788 and RAD001 resulted in more pronounced RCC growth inhibition, greater rates of G0/G1 cells and lower rates of S-phase cells than either agent alone. Cell cycle proteins were much more strongly altered when both drugs were used in combination than with single drug application. The synergistic effects were observed in an asynchronous cell culture model, but were more pronounced in synchronous RCC cell cultures.

CONCLUSION

Potent anti-tumoral activitites of the multikinase inhibitors AEE788 or RAD001 have been demonstrated. Most importantly, the simultaneous use of both AEE788 and RAD001 offered a distinct combinatorial benefit and thus may provide a therapeutic advantage over either agent employed as a monotherapy for RCC treatment.

Antiproliferative effect of ascorbic acid is associated with the inhibition of genes necessary to cell cycle progression

Background

Ascorbic acid (AA), or Vitamin C, is most well known as a nutritional supplement with antioxidant properties. Recently, we demonstrated that high concentrations of AA act on PMP22 gene expression and partially correct the Charcot-Marie-Tooth disease phenotype in a mouse model. This is due to the capacity of AA, but not other antioxidants, to down-modulate cAMP intracellular concentration by a competitive inhibition of the adenylate cyclase enzymatic activity. Because of the critical role of cAMP in intracellular signalling, we decided to explore the possibility that ascorbic acid could modulate the expression of other genes.

Methods and Findings

Using human pangenomic microarrays, we found that AA inhibited the expression of two categories of genes necessary for cell cycle progression, tRNA synthetases and translation initiation factor subunits. In in vitro assays, we demonstrated that AA induced the S-phase arrest of proliferative normal and tumor cells. Highest concentrations of AA leaded to necrotic cell death. However, quiescent cells were not susceptible to AA toxicity, suggesting the blockage of protein synthesis was mainly detrimental in metabolically-active cells. Using animal models, we found that high concentrations of AA inhibited tumor progression in nude mice grafted with HT29 cells (derived from human colon carcinoma). Consistently, expression of tRNA synthetases and ieF2 appeared to be specifically decreased in tumors upon AA treatment.

Conclusions

AA has an antiproliferative activity, at elevated concentration that could be obtained using IV injection. This activity has been observed in vitro as well in vivo and likely results from the inhibition of expression of genes involved in protein synthesis. Implications for a clinical use in anticancer therapies will be discussed.

Grb2 signaling in cell motility and cancer

BACKGROUND

Metastasis is the primary cause of death in most human cancers, and understanding the molecular mechanisms underpinning this multistep process is fundamental to identifying novel molecular targets and developing more effective therapies.

OBJECTIVE/METHODS

Here we review the role of growth factor receptor-bound protein 2 (Grb2) in cancer and specifically in metastasis-related processes, and summarize the development of anticancer therapeutics selectively targeting this adapter protein.

RESULTS/CONCLUSION

Grb2 is a key molecule in intracellular signal transduction, linking activated cell surface receptors to downstream targets by binding to specific phosphotyrosine-containing and proline-rich sequence motifs. Grb2 signaling is critical for cell cycle progression and actin-based cell motility, and, consequently, more complex processes such as epithelial morphogenesis, angiogenesis and vasculogenesis. These functions make Grb2 a therapeutic target for strategies designed to prevent the spread of solid tumors through local invasion and metastasis.

Latest Discoveries and Trends in Translational Cancer Research: Highlights of the 2008 Annual Meeting of the American Association for Cancer Research

The Annual Meeting of the American Association for Cancer Research (AACR) is the world's largest and most comprehensive gathering of cancer researchers. At the 2008 AACR Annual Meeting, innovative research approaches, novel technologies, potentially life-saving therapies in the pipeline, late-breaking clinical trial findings, and new approaches to cancer prevention were presented by top scientists. Reflecting the global state of cancer research with an eye toward future trends, several areas of great science and discovery in the cancer field were shared in this report, which include cancer biomarkers, the role of microRNAs in cancer research, cancer stem cells, tumor microenvironment, targeted therapy, and cancer prevention. This article presents an overview of hot topics discussed at the 2008 AACR Annual Meeting and recapitulates some scientific sessions geared toward new technologies, recent progress, and current challenges reported by cancer researchers. For those who did not attend the meeting, this report may serve as a highlight of this important international cancer research meeting.