The CRKL gene encoding an adaptor protein is amplified, overexpressed, and a possible therapeutic target in gastric cancer

<p>Abstract</p> <p>Background</p> <p>Genomic DNA amplification is a genetic factor involved in cancer, and some oncogenes, such as <it>ERBB2</it>, are highly amplified in gastric cancer. We searched for the possible amplification of other genes in gastric cancer.</p> <p>Methods and Results</p> <p>A genome-wide single nucleotide polymorphism microarray analysis was performed using three cell lines of differentiated gastric cancers, and 22 genes (including <it>ERBB2</it>) in five highly amplified chromosome regions (with a copy number of more than 6) were identified. Particular attention was paid to the <it>CRKL</it> gene, the product of which is an adaptor protein containing Src homology 2 and 3 (SH2/SH3) domains. An extremely high <it>CRKL</it> copy number was confirmed in the MKN74 gastric cancer cell line using fluorescence <it>in situ</it> hybridization (FISH), and a high level of CRKL expression was also observed in the cells. The RNA-interference-mediated knockdown of CRKL in MKN74 disclosed the ability of CRKL to upregulate gastric cell proliferation. An immunohistochemical analysis revealed that CRKL protein was overexpressed in 24.4% (88/360) of the primary gastric cancers that were analyzed. The <it>CRKL</it> copy number was also examined in 360 primary gastric cancers using a FISH analysis, and <it>CRKL</it> amplification was found to be associated with CRKL overexpression. Finally, we showed that MKN74 cells with <it>CRKL</it> amplification were responsive to the dual Src/BCR-ABL kinase inhibitor BMS354825, likely via the inhibition of CRKL phosphorylation, and that the proliferation of MKN74 cells was suppressed by treatment with a CRKL-targeting peptide.</p> <p>Conclusion</p> <p>These results suggested that CRKL protein is overexpressed in a subset of gastric cancers and is associated with <it>CRKL</it> amplification in gastric cancer. Furthermore, our results suggested that CRKL protein has the ability to regulate gastric cell proliferation and has the potential to serve as a molecular therapy target for gastric cancer.</p

Serotonin Augments Gut Pacemaker Activity via 5-HT3 Receptors

Serotonin (5-hydroxytryptamine: 5-HT) affects numerous functions in the gut, such as secretion, muscle contraction, and enteric nervous activity, and therefore to clarify details of 5-HT's actions leads to good therapeutic strategies for gut functional disorders. The role of interstitial cells of Cajal (ICC), as pacemaker cells, has been recognised relatively recently. We thus investigated 5-HT actions on ICC pacemaker activity. Muscle preparations with myenteric plexus were isolated from the murine ileum. Spatio-temporal measurements of intracellular Ca2+ and electric activities in ICC were performed by employing fluorescent Ca2+ imaging and microelectrode array (MEA) systems, respectively. Dihydropyridine (DHP) Ca2+ antagonists and tetrodotoxin (TTX) were applied to suppress smooth muscle and nerve activities, respectively. 5-HT significantly enhanced spontaneous Ca2+ oscillations that are considered to underlie electric pacemaker activity in ICC. LY-278584, a 5-HT3 receptor antagonist suppressed spontaneous Ca2+ activity in ICC, while 2-methylserotonin (2-Me-5-HT), a 5-HT3 receptor agonist, restored it. GR113808, a selective antagonist for 5-HT4, and O-methyl-5-HT (O-Me-5-HT), a non-selective 5-HT receptor agonist lacking affinity for 5-HT3 receptors, had little effect on ICC Ca2+ activity. In MEA measurements of ICC electric activity, 5-HT and 2-Me-5-HT caused excitatory effects. RT-PCR and immunostaining confirmed expression of 5-HT3 receptors in ICC. The results indicate that 5-HT augments ICC pacemaker activity via 5-HT3 receptors. ICC appear to be a promising target for treatment of functional motility disorders of the gut, for example, irritable bowel syndrome

Granulocyte Colony-Stimulating Factor-Producing Carcinoma of Unknown Primary Site

Granulocyte colony-stimulating factor (G-CSF)-producing nonhematopoietic malignancies have been reported in various organs and are associated with a poor clinical outcome. Moreover, carcinoma of unknown primary site (CUP) is an uncommon malignancy that occurs in about 2-6% of cancer patients. CUP also has a poor prognosis due to its missing profile. Since both G-CSF-producing carcinoma and CUP are rare, G-CSF-producing CUP (GCSF-CUP) is considered to have an even poorer prognosis and is seldom encountered. Herein, we report the case of a GCSF-CUP patient. A 75-year-old man was admitted to our hospital complaining of cervical lymphadenopathy. Multiple bulky lymph nodes without a primary site were revealed by image analysis. His complete blood count showed leukocytosis, and his blood chemistry panel indicated highly elevated levels of G-CSF. Although the patient was treated with combination chemotherapy of carboplatin, paclitaxel, bevacizumab and erlotinib, he died of intestinal perforation due to tumor invasion 23 days after the start of the therapy. An autopsy confirmed that the tumor was positive for anti-G-CSF antibody, but the primary site was still not detected

Carcinoma of Unknown Primary Site Treated with Carboplatin + Paclitaxel + Bevacizumab + Erlotinib and Its Maintenance Chemotherapy

About 3% of all cancer patients suffer from carcinoma of unknown primary site (CUP). In spite of its rarity, we will encounter them. While CUPs manifest a wide variety of clinical presentations, they have often resulted in poor prognosis. Although platinum/taxane combination chemotherapy, e.g. carboplatin (CBDCA) + paclitaxel (PTX) is widely used for patients suffering from CUP, the response rate is only about 30-40% and the median overall survival (OS) is only 9 months, which means that improvement is needed. Among the new regimens, the combination of CBDCA, PTX, bevacizumab (BEV) and erlotinib is thought to be highly promising. Herein, we report a case with CUP treated with this regimen and his maintenance therapy. Our patient was a 75-year-old man who was admitted with a left neck lump. CT revealed systemic massive lymphadenopathy. In spite of various investigations for primary origin, he was diagnosed with CUP and treated with CBDCA + PTX + BEV + erlotinib (AUC 6 + 175 mg/m2 + 15 mg/kg + 150 mg). Since the evaluation of the efficacy indicated partial response, maintenance chemotherapy (BEV and erlotinib) was performed. Chemotherapy was continued for 9 months until the patient was in a progressive disease state with meningeal dissemination. He died 12 months after the initiation of chemotherapy, which is a longer period than the previously reported OS. Of note, according to our case, CBDCA + PTX + BEV + erlotinib and its maintenance chemotherapy are feasible and well tolerated for CUP