Effect of a toxic Microcystis aeruginosa lysate on the mRNA expression of proto-oncogenes and tumor suppressor genes in zebrafish.

Cyanobacterial blooms of Microcystis aeruginosa represent a significant risk to the environment and have become a worldwide concern. M. aeruginosa can produce the hepatotoxins microcystins (MCs) with potential for tumor promotion. The present study evaluated the time-dependent effects in the transcription of tumor-related genes in the zebrafish, Danio rerio, exposed to dilutions of a M. aeruginosa lysate containing 3.5 and 54.6 µg L-1 MCs. We used a cultured M. aeruginosa strain, RST 9501, which contains mainly the variant [D-Leu1] MC-LR and originated from the Patos Lagoon Estuary (RS, Brazil). The exposure caused short-term repression of tumor suppressor genes and long-term repression of proto-oncogenes. These responses were more evident for p53 that was repressed with exposure for 6, 24 and 96 h, and fosab and myca that were consistently repressed with exposure for 384 h, when fish were exposed to both M. aeruginosa lysate dilutions, compared to controls (p < 0.05). The suppressor genes, baxa and gadd45α, and the proto-oncogene, junba, were suppressed mainly at 96 h, where both dilutions of the lysate caused repression compared to controls (p < 0.05). The p53 gene was the only gene to be induced; this occurred in fish exposed to lysate containing 3.5 µg L-1 for 384 h. This is the first study to show that M. aeruginosa containing an environmentally relevant concentration of [D-Leu1] MC-LR could cause time-dependent repression of proto-oncogenes and tumor suppressor genes in fish. The results suggest that short-term repression of tumor suppressor genes could participate in the mechanism of tumor promotion caused by M. aeruginosa in fish.

Regulation of mRNA gene expression of members of the NF-κB transcription factor gene family by angiotensin II and relaxin 2 in normal and cancer prostate cell lines.

An increasing number of researchers are focusing on the influence of local peptide hormones such as angiotensin II (Ang II) and relaxin 2 (RLN2) in the regulation of inflammation and carcinogenesis. The interaction between the renin­angiotensin system (RAS) and relaxin family peptide system (RFPS) is known to influence the proliferation, adhesion and migration of normal and cancer prostate cell lines. The aim of the present study was to evaluate changes in the expression of nuclear factor­κB subunit 1 (NFKB1), nuclear factor­κB subunit 2 (NFKB2), REL proto­oncogene nuclear factor­κB p65 subunit (REL), RELA proto­oncogene nuclear factor­κB subunit (RELA) and RELB proto­oncogene nuclear factor­κB subunit (RELB) mRNA caused by Ang II and RLN2. The members of NF­kB family are involved in many processes associated with cancer development and metastasis. Reverse transcription­quantitative polymerase chain reaction analysis identified that both peptide hormones have an influence on the relative expression of nuclear factor­κB. Following treatment with either peptide, NFKB1 expression was downregulated in all prostate cancer cell lines (LNCaP, DU­145 and PC3), but not in normal epithelial cells (PNT1A). Conversely, RELB mRNA was enhanced only in non­cancerous prostate cells. RELA expression was strongly stimulated in the most aggressive cell line, whereas REL mRNA was unchanged. In many cases, the effect was strictly dependent on the cell line and/or the type of peptide: Ang II increased expression of both RELA and REL genes in the androgen­dependent cell line while RLN2 enhanced NFKB2 and RELA mRNA in androgen­independent cells (DU­145). Further research is needed to understand the regulation of NF­κB family members by key renin­angiotensin system and RFPS peptides in prostate cancer cells; however, prostate carcinogenesis appears to be influenced by the balance between the cross­regulation of nuclear factor­κB (NF­κB) and androgen receptor pathways by Ang II and relaxin 2.

The herbal medicine Melissa officinalis extract effects on gene expression of p53, Bcl-2, Her2, VEGF-A and hTERT in human lung, breast and prostate cancer cell lines.

INTRODUCTION: Earlier, we verified that Melissa officinalis extract (MOE) elicits potent antiproliferative effects on different human cancer cells. To gain insights into the molecular mechanisms accounting for the cytotoxic effects of MOE, we assessed the expression patterns of several prominent molecules with therapeutic potential in cancer by Quantitative PCR (Q-PCR). METHODS: A549, MCF-7 and PC3 cancer cells were grown in complete RPMI 1640 and seeded in 24 well micro plates. After incubation for 72h, 100µg/ml of MOE was added and the cells were further incubated for 72h. Afterwards, the cells were subjected to RNA extraction for the means of Q-PCR. RESULTS: Our results indicated that in PC3 cancer cells, MOE resulted in a significant downregulation of VEGF-A (0.0004 fold), Bcl-2 (0.001 fold), Her2 (0.02 fold), and hTERT (0.023 fold) compared to the untreated control. In addition, VEGF-A and hTERT mRNA were significantly downregulated in MCF-7 and A549 cancer cells, as well. Notably, high anti-angiogenic activity was closely associated with a high anti-telomerase activity of MOE in studying cancer cells. The decrease in VEGF-A expression was significantly superior than that of hTERT downregulation, as PC3 cancer cells with the highest hTERT down regulation (0.023) presented the highest anti VEGF activity (0.0004 fold), whereas MCF-7 cells with the lowest hTERT inhibition (0.213) showed the lowest VEGF inhibition(0.0435) among the three studied cancer cells. We noticed that the modulation of VEGF-A and hTERT gene expression can be considered as a common target, accounting for the therapeutic potential of MOE on human breast, lung and prostate cancer cells. CONCLUSION: Altogether, it is suggested that the potent antiproliferative activity of the hydroalcoholic extract of Melissa officinalis is somehow explainable by its high potency to inhibit expression of the prominent oncogenes Bcl2, Her2, VEGF-A and hTERT in prostate cancer. In tumors with functional p53, including MCF-7 and A549 cancer cells, the role of p53, Bcl2 and Her2 is less significant. It appears that MOE exerts its antiproliferative effects in these cancer cells partly via concurrent downregulation of VEGF-A and hTERT. Additional studies are needed to clarify the role of other active molecules in cancer cells harboring functional p53.

SRC kinase inhibition with saracatinib limits the development of osteolytic bone disease in multiple myeloma.

Multiple myeloma (MM)-associated osteolytic bone disease is a major cause of morbidity and mortality in MM patients and the development of new therapeutic strategies is of great interest. The proto-oncogene SRC is an attractive target for such a strategy. In the current study, we investigated the effect of treatment with the SRC inhibitor saracatinib (AZD0530) on osteoclast and osteoblast differentiation and function, and on the development of MM and its associated bone disease in the 5TGM.1 and 5T2MM murine MM models. In vitro data showed an inhibitory effect of saracatinib on osteoclast differentiation, polarization and resorptive function. In osteoblasts, collagen deposition and matrix mineralization were affected by saracatinib. MM cell proliferation and tumor burden remained unaltered following saracatinib treatment and we could not detect any synergistic effects with drugs that are part of standard care in MM. We observed a marked reduction of bone loss after treatment of MM-bearing mice with saracatinib as reflected by a restoration of trabecular bone parameters to levels observed in naive control mice. Histomorphometric analyses support that this occurs through an inhibition of bone resorption. In conclusion, these data further establish SRC inhibition as a promising therapeutic approach for the treatment of MM-associated osteolytic bone disease.

Melanocytic nevi excised during B-Raf proto-oncogene (BRAF) inhibitor therapy: A study of 19 lesions from 10 patients.

BACKGROUND: There are limited descriptions of histopathology and immune profiles of new or changing melanocytic nevi in the setting of B-Raf proto-oncogene (BRAF) inhibitor therapy. OBJECTIVE: We sought to identify their distinctive features. METHODS: Clinical charts and histologic review, neuroblastoma RAS viral (v-ras) oncogene homolog genotyping, and immunohistochemistry for HMB-45, BRAFV600E, phosphorylated extracellular signal-regulated kinase (pERK), phosphorylated protein kinase B, CD4, and CD8 were performed on 19 melanocytic nevi from 10 patients and 23 control nevi. RESULTS: BRAF inhibitors were administered for metastatic melanoma (7), colonic adenocarcinoma (2), and papillary thyroid carcinoma (1). The average duration of BRAF inhibition before lesion excision was 8 months. Frequently associated histologic features included pigmentation of the stratum corneum, hyperpigmented keratinocytes, dermal melanophages, and deep HMB-45 expression. The lesions were BRAFV600E and neuroblastoma RAS viral (v-ras) oncogene homolog wild-type, expressed diffuse weak-moderate pERK, and possessed a predominance of CD8(+) in comparison with CD4(+) T lymphocytes within the dermal infiltrates. LIMITATION: This is a retrospective study of a small and heterogeneous group. CONCLUSION: The nevi associated with BRAF inhibitor therapy invariably lack BRAFV600E mutation. BRAF inhibition appears to cause an increased cytotoxic T-cell response and increased mitogen-activated protein kinase activity in BRAF wild-type lesions, supported by pERK expression, possibly resulting in an activated phenotype characterized by increased melanin pigmentation and deep HMB-45 expression.

Molecular targets in the treatment of non-small-cell lung cancer: is there hope on the horizon?

Non-small-cell lung cancer (NSCLC) is a growing concern worldwide, and its incidence continues to increase in developing countries. It has a strong association with smoking. Lung cancer remains the leading cause of cancer-related deaths in most industrialized countries and in the United States. In the last 10 years, there have been significant advancements in the understanding of molecular oncogenes and how they play a role in driving lung cancer to both grow and metastasize. Understanding this rapidly expanding field has the potential to extend life, and it is an important field for all providers to conceptualize if they are treating patients with lung cancer. Currently, > 50% of all NSCLC is linked to 1 of several known genetic driver mutations. Using online databases, expert opinion, and practice-changing trials, we review the current standards of molecular testing of NSCLC and the expanding evidence of oncogenic drivers in nonsquamous NSCLC.

Chemopreventive effects of metformin on obesity-associated endometrial proliferation.

OBJECTIVE: Obesity is a significant contributing factor to endometrial cancer risk. We previously demonstrated that estrogen-induced endometrial proliferation is enhanced in the context of hyperinsulinemia and insulin resistance. In this study, we investigate whether pharmacologic agents that modulate insulin sensitivity or normalize insulin levels will diminish the proliferative response to estrogen. STUDY DESIGN: Zucker fa/fa obese rats and lean controls were used as models of hyperinsulinemia and insulin resistance. Insulin levels were depleted in ovariectomized rats following treatment with streptozotocin, or modulated by metformin treatment. The number of BrdU-incorporated cells, estrogen-dependent proliferative and antiproliferative gene expression, and activation of mTOR and ERK1/2 MAPK signaling were studied. A rat normal endometrial cell line RENE1 was used to evaluate the direct effects of metformin on endometrial cell proliferation and gene expression in vitro. RESULTS: Streptozotocin lowered circulating insulin levels in obese rats and decreased the number of BrdU-labeled endometrial cells even in the presence of exogenous estrogen. Treatment with the insulin-sensitizing drug metformin attenuated estrogen-dependent proliferative expression of c-myc and c-fos in the obese rat endometrium compared to untreated controls and was accompanied by inhibition of phosphorylation of the insulin and IGF1 receptors (IRß/IGF1R) and ERK1/2. In vitro studies indicated metformin inhibited RENE1 proliferation in a dose-dependent manner. CONCLUSION: These findings suggest that drugs that modulate insulin sensitivity, such as metformin, hinder estrogen-mediated endometrial proliferation. Therefore, these drugs may be clinically useful for the prevention of endometrial cancer in obese women.

Effect of heparin-derived oligosaccharide on vascular smooth muscle cell proliferation and the signal transduction mechanisms involved.

PURPOSE: In this study, the effect of heparin-derived oligosaccharide (HDO) on vascular endothelial growth factor (VEGF) induced vascular smooth muscle cell (VSMC) proliferation and the signal transduction mechanisms involved were investigated. METHODS: MTT assays were used to measure VSMC proliferation, flow cytometry to analyze cell cycle distribution, RT-PCR for detection of gene transcript levels, and cell-based ELISA, Western blotting and immunocytochemical methods to detect the expression of PKC-α, ERK 1/2, p-ERK 1/2, Akt, p-Akt, p-PDK1 and p-GSK-3ß. RESULTS: HDO at concentrations of 0.01, 0.1 and 1 µmol·L(-1) dose-dependently inhibited VEGF-induced VSMC proliferation with inhibition indices of 6.8 %, 13.1 % and 28.9 %, respectively. Similar concentrations of HDO dose-dependently decreased the percentage of VEGF-induced cells in S phase to 3.6 %, 3.4 %, and 5.4 %, while increasing that of cells arrested in the G0/G1 phase to 80 %, 82 % and 83.6 %. HDO at 0.01, 0.1 or 1 µmol·L(-1) inhibited VEGF-induced PKC-α mRNA expression, with inhibition indices of 9.2 %, 16.1 % and 54.0 %. HDO at 0.1 or 1 µmol·L(-1) inhibited VEGF-induced proto-oncogene mRNA expression, with inhibition indices of 5.2 % and 6.6 % for c-jun, 8.8 % and 11.6 % for c-myc, and 6.5 % and 11.9 % for c-fos, respectively. Additionally, treatment with 0.01, 0.1 or 1 µmol·L(-1) HDO, inhibited VEGF-induced expression of some proliferation related proteins with inhibition indices of 33.2 %, 56.3 % and 77.0 % for PKC-α, 33.7 %, 38.7 % and 53.2 % for p-Akt, 3.5 %, 24.2 % and 49.3 % for p-ERK 1/2, 39.2 %, 71.8 % and 80.7 % for p-PDK 1 and 41.4 %, 89.4 % and 92.4 % for p-GSK-3ß, respectively. The results showed that HDO inhibited PKC-α, c-jun, c-fos and c-myc mRNA transcription, and also down-regulated phosphorylation levels of ERK 1/2 and Akt. CONCLUSION: Our study demonstrates that HDO inhibits transcription of proliferation-related proto-oncogenes and arrests G1/S transition through inhibition of the PKC, MAPK and Akt/PI3K pathways in association with inhibition of VSMC proliferation. This altered molecular signature may explain one mechanism of HDO-mediated inhibition of VSMC proliferation.

Phorbol esters from Jatropha meal triggered apoptosis, activated PKC-δ, caspase-3 proteins and down-regulated the proto-oncogenes in MCF-7 and HeLa cancer cell lines.

Jatropha meal produced from the kernel of Jatropha curcas Linn. grown in Malaysia contains phorbol esters (PEs). The potential benefits of PEs present in the meal as anticancer agent are still not well understood. Hence, this study was conducted to evaluate the cytotoxic effects and mode of actions of PEs isolated from Jatropha meal against breast (MCF-7) and cervical (HeLa) cancer cell lines. Isolated PEs inhibited cells proliferation in a dose-dependent manner of both MCF-7 and HeLa cell lines with the IC50 of 128.6 ± 2.51 and 133.0 ± 1.96 µg PMA equivalents/mL respectively, while the values for the phorbol 12-myristate 13-acetate (PMA) as positive control were 114.7 ± 1.73 and 119.6 ± 3.73 µg/mL, respectively. Microscopic examination showed significant morphological changes that resemble apoptosis in both cell lines when treated with PEs and PMA at IC50 concentration after 24 h. Flow cytometry analysis and DNA fragmentation results confirmed the apoptosis induction of PEs and PMA in both cell lines. The PEs isolated from Jatropha meal activated the PKC-δ and down-regulated the proto-oncogenes (c-Myc, c-Fos and c-Jun). These changes probably led to the activation of Caspase-3 protein and apoptosis cell death occurred in MCF-7 and HeLa cell lines upon 24 h treatment with PEs and PMA. Phorbol esters of Jatropha meal were found to be promising as an alternative to replace the chemotherapeutic drugs for cancer therapy.

Overcoming resistance to EGFR inhibitor in head and neck cancer: a review of the literature.

Head and neck squamous cell carcinoma (HNSCC) affects over half a million people worldwide. Despite advances in therapy, only half of the patients are alive in 5 years. Epidermal growth factor receptor (EGFR) is overexpressed in approximately 90% of the tumors, and it is correlated with poor response to treatment and worse outcome. Multiple therapies targeting this pathway have been tested. Cetuximab is the only EGFR inhibitor approved in HNSCC, but response rates are low. More recently, significant interest has focus on identifying mechanisms of acquired and de novo EGFR blockage resistance. Here we review some of these mechanisms and describe strategies to overcome that resistance.

Proteomic profiling of human colon cancer cells treated with the histone deacetylase inhibitor belinostat.

The anticancer drug belinostat is a hydroxamate histone deacetylase inhibitor that has shown significant antitumour activity in various tumour models and also in clinical trials. In this study, we utilized a proteomic approach in order to evaluate the effect of this drug on protein expression in the human colon cancer cell line HCT116. Protein extracts from untreated HCT116 cells, and cells grown for 24 h in the presence of 1 and 10 muM belinostat were analysed by 2-D gel electrophoresis. Proteins were visualized by colloidal Coomassie blue staining and quantitative analysis of gel images revealed 45 unique differentially expressed proteins that were identified by LC-MSMS analysis. Among these proteins, of particular interest are the downregulated proteins nucleophosmin and stratifin, and the upregulated proteins nucleolin, gelsolin, heterogeneous nuclear ribonucleoprotein K, annexin 1, and HSP90B that all were related to the proto-oncogene proteins p53, Myc, activator protein 1, and c-fos protein. The modulation of these proteins is consistent with the observations that belinostat is able to inhibit clonogenic cell growth of HCT116 cells and the biological role of these proteins will be discussed.

Pro-oncogenic and anti-oncogenic pathways: opportunities and challenges of cancer therapy.

Carcinogenesis is the uncontrolled growth of cells gaining the potential to invade and disrupt vital tissue functions. This malignant process includes the occurrence of 'unwanted' gene mutations that induce the transformation of normal cells, for example, by overactivation of pro-oncogenic pathways and inactivation of tumor-suppressive or anti-oncogenic pathways. It is now recognized that the number of major signaling pathways that control oncogenesis is not unlimited; therefore, suppressing these pathways can conceivably lead to a cancer cure. However, the clinical application of cancer intervention has not matched up to scientific expectations. Increasing numbers of studies have revealed that many oncogenic-signaling elements show double faces, in which they can promote or suppress cancer pathogenesis depending on tissue type, cancer stage, gene dosage and their interaction with other players in carcinogenesis. This complexity of oncogenic signaling poses challenges to traditional cancer therapy and calls for considerable caution when designing an anticancer drug strategy. We propose future oncology interventions with the concept of integrative cancer therapy.

Data requirements for risk assessment of furan in food.

Furan is an organic, volatile compound used in various chemical-manufacturing industries. Headspace gas chromatography is the analytical method of choice for obtaining reliable results on its occurrence. The presence of furan in some food items has been known since the late 1970s, but a US Food and Drug Administration (FDA) survey published in 2004 revealed the occurrence of furan in a broad variety of canned and jarred foods, including baby food, that undergo heat treatment. Furan is carcinogenic in rats and mice, showing a dose-dependent increase in hepatocellular adenomas and carcinomas. In rats, a dose-dependent increase of mononuclear leukaemia is evident and a very high incidence of cholangiocarcinomas of the liver, even at the lowest dose tested. There is evidence to indicate that furan-induced carcinogenicity is probably attributable to a genotoxic mechanism. However, chronic toxicity with secondary cell proliferation may indirectly amplify the tumour response. From the available data, there is a relative small difference between possible human exposure and the doses in experimental animals required to produce carcinogenic effects. However, reliable risk assessment requires further data on both toxicity and exposure. The European Food Safety Authority's (EFSA) Scientific Panel on Contaminants in the Food Chain (CONTAM) recommended these studies as part of a reliable risk assessment of furan in food.

Role of insulin-like growth factor 1 receptor signalling in cancer.

The insulin-like growth factor (IGF-1) signalling is highly implicated in cancer. In this signalling the IGF-1 receptor (IGF-1R) is unquestionable, the predominating single factor. IGF-1R is crucial for tumour transformation and survival of malignant cell, but is only partially involved in normal cell growth. This is in part due to the interactions with oncogenes. Recent findings suggest a close interplay with the p53/MDM2 pathway. Disturbances in components in the p53/MDM2/IGF-1R network may cause IGF-1R upregulation and growth advantage for the cancer cell. Targeting of IGF-1R is more and more seen as a promising option for future cancer therapy. Single chain antibodies and small molecules with selective effects on IGF-1R dependent malignant growth are of particular interest. Forthcoming clinical trials are welcome and will indeed be the only way to evaluate the impact of IGF-1R targeting in human cancer.

Effects of topoisomerase 2 inhibitors on the MLL gene in children receiving chemotherapy: a prospective study.

The molecular effects of etoposide in haemopoietic cells suggest that mixed lineage leukaemia (MLL) abnormalities can be biomarkers of patient susceptibility to the genotoxic effects of topoisomerase 2 (topo 2) inhibitors. We have prospectively studied treatment-related MLL cleavage and rearrangement in serial samples from 71 children receiving chemotherapy, using Southern blot analysis and panhandle PCR. The results were related to patient demographics, treatment details and outcome. MLL cleavage was identified in six bone marrow samples from five patients 2-10 months after the start of therapy. There was no obvious relationship between the degree of MLL cleavage and cumulative dose or schedule of topo 2 inhibitors. Three children with low percentage (23-30%) cleavage remained well and two were still receiving treatment at study completion. One child with two consecutively positive samples and higher level of MLL cleavage (45-48%) died from treatment-related toxicities and relapsed leukaemia. A patient with haemophagocytic lymphohistiocytosis developed the highest level of MLL cleavage (50%) at 3 months and a treatment-related leukaemia with MLL rearrangement 6 months after the start of treatment. It would appear that some patients are inherently more susceptible to the genotoxic effect of topo 2 inhibitors. The degree and persistence of MLL cleavage may identify patients at risk.

Covalent coupling of a PIM-1 oncogene targeted PNA with an antennapedia derived peptide.

Peptide nucleic acids (PNA) are promising antisense molecule for blocking gene expression in cell culture or in vivo. Nevertheless because they are poor efficient to pass the cellular membrane, it is necessary to use a vectorisation agent to observe an inhibitory effect. We describe the coupling of the rhodamine labeled 17-mer antisense PNA to a fusogenic peptide from antenapedia via S-S linkage, the studies of the penetration of this complex into fibroblast cells and its inhibitory effect on pim1 targeted protononcogene.

[Matrine affects early expression of proto-oncogenes in K562 cells].

BACKGROUND & OBJECTIVE: It has been reported that matrine had the anti-tumor activity, and our previous study have provided that matrine had the effects of inhibiting proliferation and inducing differentiation in K562 cell line, but its molecular mechanism is unknown yet. METHOD: The expression of several proto-oncogenes(c-myc, c-jun, H-ras, p21, and HNF-1 alpha) in K562 cell line treated by 0.2 mg/ml matrine were measured by RT-PCR. RESULT: The c-myc, c-jun, and HNF-1 alpha mRNA of K562 cells treated by 0.2 mg/ml matrine were dramatically decreased at the early stage (3 h), while the H-ras and p21 mRNA were increased obviously at the same time. CONCLUSION: The changes of several proto-oncogenes in K562 cells treated by 0.2 mg/ml matrine may be related to inhibiting proliferation and inducing differentiation.

Molecular cloning and functional analysis of a novel cadmium-responsive proto-oncogene.

The molecular mechanisms potentially responsible for cell transformation and tumorigenesis induced by cadmium, a human carcinogen, were investigated by differential gene expression analysis of BALB/c-3T3 cells transformed with cadmium chloride (CdCl(2)). Differential display analysis of gene expression revealed consistent overexpression of mouse translation initiation factor 3 (TIF3; GenBank accession number AF271072) in the cells transformed with CdCl(2) when compared with nontransformed cells. The predicted protein encoded by TIF3 cDNA exhibited 99% similarity to human eukaryotic initiation factor 3 p36 protein. A M(r) 36,000 protein was detected in cells transfected with an expression vector containing TIF3 cDNA. Transfection of NIH3T3 cells with an expression vector containing TIF3 cDNA resulted in overexpression of the encoded protein, and this was associated with cell transformation, as evidenced by the appearance of transformed foci exhibiting anchorage-independent growth on soft agar and tumorigenic potential in nude mice. Expression of the antisense RNA against TIF3 mRNA resulted in significant reversal of oncogenic potential of the CdCl(2)-transformed BALB/c-3T3 cells. Taken together, these findings demonstrate for the first time that the cell transformation and tumorigenesis induced by CdCl(2) are due, at least in part, to the overexpression of TIF3, a novel cadmium-responsive proto-oncogene.