Activation of the Met kinase confers acquired drug resistance in FGFR-targeted lung cancer therapy

Aberrant fibroblast growth factor receptor (FGFR) activation/expression is a common feature in lung cancer (LC). In this study, we evaluated the antitumor activity of and the mechanisms underlying acquired resistance to two potent selective FGFR inhibitors, AZD4547 and BAY116387, in LC cell lines. The antitumor activity of AZD4547 and BAY1163877 was screened in 24 LC cell lines, including 5 with FGFR1 amplification. Two cell lines containing FGFR1 amplifications, H1581 and DMS114, were sensitive to FGFR inhibitors (IC50<250 nm). Clones of FGFR1-amplified H1581 cells resistant to AZD4547 or BAY116387 (H1581AR and H1581BR cells, respectively) were established. Receptor tyrosine kinase (RTK) array and immunoblotting analyses showed strong overexpression and activation of Met in H1581AR/BR cells, compared with that in the parental cells. Gene set enrichment analysis against the Kyoto Encyclopedia of Genes and Genomes (KEGG) database showed that cytokine-cytokine receptor interaction pathways were significantly enriched in H1581AR/BR cells, with Met contributing significantly to the core enrichment. Genomic DNA quantitative PCR and fluorescent in situ hybridization analyses showed MET amplification in H1581AR, but not in H1581BR, cells. Met amplification drives acquired resistance to AZD4547 in H1581AR cells by activating ErbB3. Combination treatment with FGFR inhibitors and an anaplastic lymphoma kinase (ALK)/Met inhibitor, crizotinib, or Met-specific short interfering RNA (siRNA) synergistically inhibited cell proliferation in both H1581AR and H1581BR cells. Conversely, ectopic expression of Met in H1581 cells conferred resistance to AZD4547 and BAY1163877. Acquired resistance to FGFR inhibitors not only altered cellular morphology, but also promoted migration and invasion of resistant clones, in part by inducing epithelial-to-mesenchymal transition. Taken together, our data suggest that Met activation is sufficient to bypass dependency on FGFR signaling. Concurrent inhibition of the Met and FGFR pathways may have synergistic clinical benefits when targeting FGFR-dependent LC.

Jet printing of convex and concave polymer micro-lenses

We describe a novel approach for fabricating customized convex as well as concave micro-lenses using substrates with sophisticated pinning architecture and utilizing a drop-on-demand jet printer. The polymeric lens material deposited on the wafer is cured by UV light irradiation yielding lenses with high quality surfaces. Surface shape and roughness of the cured polymer lenses are characterized by white light interferometry. Their optical quality is demonstrated by imaging an USAF1951 test chart. The evaluated modulation transfer function is compared to Zemax simulations as a benchmark for the fabricated lenses.

Roscovitine has anti-proliferative and pro-apoptotic effects on glioblastoma cell lines: A pilot study

Purine analogue roscovitine, a cyclin-dependent kinase (CDK) inhibitor, has shown strong anti-proliferative and pro-apoptotic effects in solid and hematologic cancers such as non small-cell lung cancer and lymphomas. It targets CDK2, 7 and 9 preferentially, which are also overexpressed in glioblastoma. Τherefore, the biological effects of roscovitine in glioblastoma cell lines were investigated. Glioblastoma A172 and G28 cell lines were incubated with serial concentrations of roscovitine for 24-120 h. Proliferation was measured using the xCELLigence Real-Time Cell Analyzer, an impedance‑based cell viability system. Cell cycle distribution was assessed by flow cytometry and gene expression was quantified by quantitative RT-PCR and western blot analysis. Roscovitine exhibited a clear dose-dependent anti‑proliferative and pro‑apoptotic effect in the A172 cell line, while G28 cells showed a anti-proliferative effect only at 100 µM. The results of the flow cytometric (FACS) analysis revealed a dose-dependent increase of the G2/M and sub-G1 fractions in A172 cells, while G28 cells responded with an elevated sub-G1 fraction only at the highest concentration. Roscovitine led to a dose‑dependent decrease of transcripts of p53, CDK 7 and cyclins A and E and an increase of >4-fold of p21 in A172 cells. In G28 cells, a dose‑dependent induction of CDK2, p21 and cyclin D was observed between 10 and 50 µM roscovitine after 72 h, however, at the highest concentration of 100 µM, all investigated genes were downregulated. Roscovitine exerted clear dose-dependent anti-proliferative and pro-apoptotic effects in A172 cells and less distinct effects on G28 cells. In A172 cells, roscovitine led to G2/M arrest and induced apoptosis, an effect accompanied by induced p21 and a reduced expression of CDK2, 7 and 9 and cyclins A and E. These effects requre further studies on a larger scale to confirm whether roscovitine can be used as a therapeutic agent against glioblastoma.

Heat dissipation after nonanatomical lung resection using a laser is mainly due to emission to the environment: an experimental ex vivo study

Laser-directed resection of lung metastases is performed more frequently in recent years. The energy-loaded laser rays heat up the lung tissue, considerably. It is still unclear which mechanism is more important for tissue heat dissipation: the lung perfusion or the tissue emission. Therefore, we created a special experimental model to investigate the spontaneous heat dissipation after nonanatomical lung resection using a diode-pumped laser with a high output power. Experiments were conducted on paracardiac pig lung lobes (n = 12) freshly dissected at the slaughterhouse. Nonanatomical resection of lung parenchyma was performed without lobe perfusion in group 1 (n = 6), while group 2 (n = 6) was perfused at a physiological pressure of 25 cm H2O at 37 °C with saline via the pulmonary artery. For this, we used a diode-pumped neodymium-doped yttrium aluminum garnet (Nd:YAG) LIMAX® 120 laser (Gebrüder Martin GmbH & Co. KG, Tuttlingen, Germany) with a wavelength of 1,318 nm and a power output of 100 W. Immediately after completing laser resection, the lungs were monitored with an infrared camera (Type IC 120LV; Trotec, Heinsberg, Germany) while allowed to cool down. The resection surface temperature was taken at 10-s intervals and documented in a freeze-frame until a temperature of 37 °C had been reached. The temperature drop per time unit was analyzed in both groups. Immediately after laser resection, the temperature at the lung surface was 84.33 ± 8.08 °C in group 1 and 76.75 ± 5.33 °C in group 2 (p = 0.29). Group 1 attained the final temperature of 37 °C after 182.95 ± 53.76 s, and group 2 after 121.70 ± 16.02 s (p = 0.01). The temperature drop occurred exponentially in both groups. We calculated both groups' decays using nonlinear regression, which revealed nearly identical courses. The mean time of tissue temperature of >42 °C, as a surrogate marker for tissue damage, was 97.14 ± 26.90 s in group 1 and 65.00 ± 13.78 s in group 2 (p = 0.02). Heat emission to the environment surpasses heat reduction via perfusion in nonanatomically laser-resected lung lobes. In developing a cooling strategy, a topical cooling method would be promising.

[Diagnosis of and therapy for hepatocellular carcinoma]

The interdisciplinary guidelines at the S3 level on the diagnosis of and therapy for hepatocellular carcinoma (HCC) constitute an evidence- and consensus-based instrument that is aimed at improving the diagnosis of and therapy for HCC since these are very challenging tasks. The purpose of the guidelines is to offer the patient (with suspected or confirmed HCC) adequate, scientifically based and up-to-date procedures in diagnosis, therapy and rehabilitation. This holds not only for locally limited or focally advanced disease but also for the existence of recurrences or distant metastases. Besides making a contribution to an appropriate health-care service, the guidelines should also provide the foundation for an individually adapted, high-quality therapy. The explanatory background texts should also enable non-specialist but responsible colleagues to give sound advice to their patients concerning specialist procedures, side effects and results. In the medium and long-term this should reduce the morbidity and mortality of patients with HCC and improve their quality of life.

Embryonic transcription factors CDX2 and Oct4 are overexpressed in neuroendocrine tumors of the ileum: a pilot study

BACKGROUND

Neuroendocrine tumors (NETs) of the ileum are rare submucosal tumors that are often diagnosed at advanced stages with metastatic spread to the liver causing a carcinoid syndrome. They present as solitary or multiple tumors. In NETs, loss of sequences on chromosomes 11, 16, 18 and 22 or gain of sequences on chromosomes 17 and 19 has been described. In this study we explored the expression of two novel candidate genes, CDX2 and Oct4, in NETs of the ileum and analyzed whether the molecular expression pattern correlates with the clinical phenotype (solitary/multiple tumors).

METHODS

Data from all patients who underwent surgery for a NET of the ileum between 2000 and 2010 were retrieved from a prospective database. For each patient, frozen normal and tumor tissue was used for the comparison of gene expression levels of two putative cancer stem cell markers, CDX2 and Oct4, using real-time PCR (rtPCR). Serial slides from paraffin blocks were used for immunohistochemistry. Gene expression was compared between normal and tumor tissue as well as between solitary and multiple tumors.

RESULTS

78 patients were identified. In rtPCR, a statistically significant higher expression of CDX2 in tumor tissue (p < 0.001) compared to normal tissue was found. The expression of Oct4 was elevated in the tumors, but did not reach the level of significance (p = 0.155). The expression of both candidate genes was confirmed immunohistochemically and showed a nuclear expression pattern. There was no difference in expression between solitary and multiple tumors or between tumors that had already spread to the liver.

CONCLUSION

CDX2 is overexpressed in ileum NETs, thus playing a role in the tumorigenesis of these rare tumors. Since expression does not correlate with clinical stage or phenotype, it might be an early event in tumor development.

Apoptosis-modulating drugs for improved cancer therapy

Resistance to cell death induction has been recognized as a hallmark of cancer. Increasing understanding of the underlying molecular events regulating different cell death mechanisms like apoptosis, endoplasmic reticulum stress, autophagy, necroptosis and others has opened new possibilities for targeted interference with these pathways. While conventional chemotherapeutic agents usually inhibit cell cycle progression, DNA replication or mitosis execution, novel agents like small molecule kinase inhibitors also target survival-related kinases and signaling pathways and contribute to overcome resistance to chemotherapy and apoptosis. Additionally, antibodies targeting cellular death receptors have been described to specifically target tumor cells only. This review briefly highlights the pathways involved in (apoptotic) cell death and summarizes the current state of development of specific modulators of cell death and how they can help to improve the tolerability of chemotherapy regimens and increase survival rates in patients with advanced cancer diseases.

Novel compounds with antiangiogenic and antiproliferative potency for growth control of testicular germ cell tumours

BACKGROUND

Testicular germ cell tumour (TGCT) is the most common cause of death from solid tumours in young men and especially for platinum-refractory patients novel treatment approaches are urgently needed. Using an in silico screening approach for the detection of novel cancer drugs with inhibitory effects on the tyrosine kinase activity of growth factors (e.g., VEGFR, PDGFR), we identified two compounds (HP-2 and HP-14) with antiangiogenic and antiproliferative potency, which were evaluated in endothelial cell models and TGCT cells.

RESULTS

HP-2 and HP-14 effectively inhibited the growth of VEGFR-2-expressing TGCT cell lines (Tera-1, Tera-2 and 2102EP) and endothelial cell models, while they failed to supress the growth of VEGFR-2-lacking tumour cells. cDNA-microarrays revealed an inhibition of the expression of several growth factor receptors and related signal transduction molecules. Vascular endothelial growth factor (VEGF)-induced cell migration was also potently inhibited. Cell cycle-regulating proteins such as p21 and p27 were upregulated, leading to an S-phase arrest. Additional in vivo evaluations confirmed the antiangiogenic potency and good tolerability of the novel substances.

CONCLUSION

Our data show that the identified novel compounds inhibit the growth of TGCT cells and decrease angiogenic microvessel formation. The mode of action involves cell cycle arresting effects and changes in the expression pattern of several angiogenic genes. The novel compounds may qualify as new candidates for targeted treatment of TGCT and merit further evaluation.

Liver function under interferon/ribavirin therapy of chronic hepatitis C

BACKGROUND

Quantitative testing of liver function (QTLF) is one way to show the efficacy of antiviral treatment of Hepatitis C. Data on liver function in patients with chronic Hepatitis C during antiviral therapy are lacking. We therefore investigated if and to what extent antiviral therapy influenced quantitative testing of liver function (QTLF).

METHODOLOGY

One hundrend seven patients with chronic Hepatitis C (genotype 1) were treated with pegylated-interferon 2alpha/ribavirin for 48 weeks. Quantitative testing of liver function, including aminopyrine breath test (ABT), galactose elimination capacity (GEC), sorbitol clearance (SCl) and indocyanine green clearance (ICG) was performed before and 12 weeks after initiation of antiviral therapy. QTLF was repeated at the end of the therapy (week 48) and 6 months after therapy.

RESULTS

After 3 months of treatment, 97 patients showed normal transaminases and were negative for HCV-RNA. ABT and GEC as parameters of microsomal and cytosolic liver function were reduced in all patients before therapy initiation and returned to normal values in the therapy responders after 3 months. Parameters of liver perfusion (SCl and ICG) require one year of treatment before returning to normal levels. In non-responders, QTLF did not change during therapy, in relapsers, QTLF results deteriorated after ending the therapy.

CONCLUSION

All liver tests return to normal within one year after eradication of the Hepatitis C virus. Parameters measuring the liver plasma flow (SCI and ICG) require more time to become normal, most likely due to tissue remodelling processes.

Variants of bcl-2 specific siRNA for silencing antiapoptotic bcl-2 in pancreatic cancer

BACKGROUND AND AIMS

Pancreatic cancer remains a devastating diagnosis with only limited therapeutic options. Specific inhibition of expression of target genes has become possible using small interfering (si) RNAs. We therefore investigated how far siRNA specific for bcl-2 may serve as a therapeutic option for pancreatic cancer in vitro and in vivo.

METHODS

siRNAs targeting two different regions in the bcl-2 gene were transfected to YAP C and DAN G pancreatic carcinoma cells and human foreskin fibroblasts. Permutations were generated by changing 3' and 5' overhangs and varying the length of the paired RNA duplex. Transfection efficacy was determined using FITC labelled siRNAs and fluorescence microscopy. Cell survival and apoptosis were quantified at 24-120 hours. Pancreatic cancer xenografts in male nude mice were treated intraperitoneally with siRNAs daily for 24 days. siRNA pharmacokinetics in vivo were assessed using radioactively labelled siRNAs. Total protein and RNA were extracted for western Blot analysis and quantitative polymerase chain reaction.

RESULTS AND CONCLUSIONS

Bcl-2 specific siRNAs specifically inhibited expression of the target gene in vitro and in vivo. Antiproliferative and proapoptotic effects were observed in tumour cells but not in fibroblasts or non-malignant tissues. siRNA permutations and diverse overhangs influenced gene silencing efficacy. siRNA was quickly distributed to all organs and excreted via the kidney and liver. Bcl-2 specific siRNA is a promising adjunctive treatment for pancreatic carcinoma.

Overadditive anti-proliferative and pro-apoptotic effects of a combination therapy on colorectal carcinoma cells

The prognosis of advanced colorectal carcinoma (CC) is poor. Established chemotherapy shows only limited efficacy but significant side effects. We investigated how far a combination of tamoxifen (TAM), 9-cis-retinoic acid (CRA) and the fluoroquinolone ciprofloxacin (CIP) synergize to inhibit proliferation and promote apoptosis of CC cells in vitro. The CC cell lines LOVO, CC-531 and SW-403 were incubated with TAM, CRA and CIP (10(minus;4)-10(minus;6) M) as single agents and in combination. Cell proliferation was assessed by bromodeoxyuridin incorporation. Apoptosis was quantified immunohistochemically and by FACS analysis after staining with propidium iodide. Changes in the expression of caspase 3, bax, bcl-2 and p21cip/waf were assessed by quantitative Western blotting. CRA and TAM monotherapy was moderately effective. Their combination enhanced apoptosis from 60% to more than 80% in all cell types. Apoptosis was paralleled by inhibition of proliferation and further potentiated by addition of CIP. The combination effectively up-regulated caspase 3 and bax and down-regulated bcl-2 and p21cip/waf. Combinations of biomodulaters act synergistically to inhibit proliferation and promote apoptosis in CC cells. Due to their known safety profile, this justifies clinical trials for colorectal cancer using combinations of these biological response modifiers.

Overadditive anti-proliferative and pro-apoptotic effects of a combination therapy on colorectal carcinoma cells

The prognosis of advanced colorectal carcinoma (CC) is poor. Established chemotherapy shows only limited efficacy but significant side effects. We investigated how far a combination of tamoxifen (TAM), 9-cis-retinoic acid (CRA) and the fluoroquinolone ciprofloxacin (CIP) synergize to inhibit proliferation and promote apoptosis of CC cells in vitro. The CC cell lines LOVO, CC-531 and SW-403 were incubated with TAM, CRA and CIP (10(minus;4)-10(minus;6) M) as single agents and in combination. Cell proliferation was assessed by bromodeoxyuridin incorporation. Apoptosis was quantified immunohistochemically and by FACS analysis after staining with propidium iodide. Changes in the expression of caspase 3, bax, bcl-2 and p21cip/waf were assessed by quantitative Western blotting. CRA and TAM monotherapy was moderately effective. Their combination enhanced apoptosis from 60% to more than 80% in all cell types. Apoptosis was paralleled by inhibition of proliferation and further potentiated by addition of CIP. The combination effectively up-regulated caspase 3 and bax and down-regulated bcl-2 and p21cip/waf. Combinations of biomodulaters act synergistically to inhibit proliferation and promote apoptosis in CC cells. Due to their known safety profile, this justifies clinical trials for colorectal cancer using combinations of these biological response modifiers.

Ciprofloxacin induces apoptosis and inhibits proliferation of human colorectal carcinoma cells

Efficacy of chemotherapy in advanced stages of colorectal tumours is limited. The quinolone antibiotic ciprofloxacin was recently shown to inhibit growth and to induce apoptosis in human bladder carcinomas cells. We investigated the effect of ciprofloxacin on colon carcinoma lines in vitro. CC-531, SW-403 and HT-29 colon carcinoma and HepG2 hepatoma cells (control cells) were exposed to ciprofloxacin. Proliferation was assessed by bromodeoxyuridine-incorporation into DNA and apoptosis was measured by flow cytometry after propidium iodide or JC-1 staining. Expression of anti-apoptotic Bcl-2 and pro-apoptotic Bax was analyzed by semiquantitative Western blot analysis and activity of caspases 3, 8 and 9 by substrate-cleavage assays. Ciprofloxacin suppressed DNA synthesis of all colon carcinoma cells time- and dose-dependently, whereas the hepatoma cells remained unaffected. Apoptosis reached its maximum between 200 and 500 microg ml(-1). This was accompanied by an upregulation of Bax and of the activity of caspases 3, 8 and 9, and paralleled by a decrease of the mitochondrial membrane potential. Ciprofloxacin decreases proliferation and induces apoptosis of colon carcinoma cells, possibly in part by blocking mitochondrial DNA synthesis. Therefore, qualification of ciprofloxacin as adjunctive agent for colorectal cancer should be evaluated.

Combined in vitro anti-tumoral action of tamoxifen and retinoic acid derivatives in hepatoma cells

Chemotherapy does not have a prominent role in the treatment of hepatoma. However, an acyclic retinoid prevented tumor recurrence post-hepatectomy, and tamoxifen (TAM) induced apoptosis in tumor cells. Combination therapy of these agents on proliferation and apoptosis of hepatoma cells has not been explored. HepG2, Hep1B, Hepa1-6 and MH1C1 hepatoma cells were incubated with TAM, 9-cis- and all-trans retinoic acid (CRA, ATRA, respectively) alone or in combination. Proliferation rate was assessed and apoptosis was analyzed by flow cytometry, immunostaining, caspase activity assays and the expression of apoptosis- and/or cell cycle-related molecules. CRA and TAM, but not ATRA monotherapy were moderately effective. Apoptosis was accompanied by upregulation of caspase 3 and 8 activity, and increased p27, bax, caspase 3 expression, while the levels of p21cip/waf and bcl-2 were unchanged or decreased. Combination therapy enhanced apoptosis from a maximum of 60% after monotherapy to more than 90% after 96 h in all cell types. Pro-apoptotic effects were paralleled by inhibition of proliferation. Combination of TAM and CRA, but not ATRA, have an additive to synergistic anti-proliferative and pro-apoptotic effect on HCC cells. This justifies trials for HCC using combinations of these biological response modifiers.

PCR-SSCP analysis of human adrenocortical adenomas: absence of K-ras gene mutations

Little is known about the pathogenesis and etiology of benign tumors of the adrenal cortex. A variety of cellular oncogenes and tumor suppressor genes has been studied so far. The role of K-ras in this process is not yet clearly understood. Recent findings suggest a strong influence of mutated K-ras in the pathogenesis of adrenal adenomas (Lin et al., 1998). Therefore we studied 40 human adrenal tumors for mutations in the coding region of the cellular proto-oncogene K-ras by PCR-SSCP (Single-strand conformation polymorphism) analysis. We did not identify any activating mutation in the coding region of the K-ras gene. We conclude that activating mutations of the K-ras gene are not a major cause for the development of adrenal adenomas, if at all.