Kanoko Kozawa

Increased sensitivity to cisplatin in gastric cancer by antisense inhibition of the her-2/neu (c-erbB-2) gene.

Background: The c-erbB-2 oncogene encodes a transmembrane tyrosine kinase receptor and its abnormal expression may be related to the prognosis of gastric cancer. Gastric cancer is relatively resistant to various drugs, including cisplatin. Cisplatin is widely used in cancer chemotherapy, but the mechanisms of drug resistance are not yet known. Methods: We used the human gastric cancer cell lines MKN-7 and KATO-III, which express the c-erbB-2 oncogene, as a model for relative resistance to cisplatin. We investigated whether inhibition with antisense oligonucleotides against c-erbB-2 increased the sensitivity of MKN-7 and KATO-III cells to cisplatin. Results: Antisense oligonucleotides for c-erbB-2 inhibited the expression of c-erbB-2 mRNA and protein and increased sensitivity to cisplatin, but not to other drugs, in MKN-7 and KATO-III cells. Cell growth was also inhibited by c-erbB-2 antisense oligonucleotides but not sense oligonucleotides. Conclusions: These findings indicate that c-erbB-2 expression in gastric cancer is one of the factors related to cisplatin sensitivity, and that anti-c-erbB-2 antisense oligonucleotides induced increased sensitivity to cisplatin.

Modification of the sensitivity to cisplatin with c-myc over-expression or down-regulation in colon cancer cells

Human colon cancer SW480 cells express the c-myc gene. On the other hand, SW480DDP cell lines resistant to cisplatin exhibited decreased c-myc gene expression, but their cell growth rates remained similar to those of their parental cells. Antisense oligonucleotides to c-myc inhibited c-myc expression and induced increased resistance to cisplatin in SW480 cells. In contrast, SW480DDP cells showed increased c-myc expression and reversed sensitivity to cisplatin when these cells were transfected with c-myc cDNA from the pLNCX plasmid. Moreover, SW480DDP cells transfected with c-myc cDNA induced apoptosis when exposed to cisplatin, but not SW480 cells transfected with an antisense sequence for c-myc. Transfection either with a c-myc antisense sequence or c-myc cDNA to these cells did not change their growth rates. Thus enforced expression of c-myc in SW480 and SW620 lines sensitizes cells to cisplatin-induced apoptosis, whereas the down-regulation of c-myc in SW480DDP and SW620DDP increases cisplatin resistance when using antisense strategy.

Enhanced Auditory Brainstem Response and Parental Bonding Style in Children with Gastrointestinal Symptoms

Background The electrophysiological properties of the brain and influence of parental bonding in childhood irritable bowel syndrome (IBS) are unclear. We hypothesized that children with chronic gastrointestinal (GI) symptoms like IBS may show exaggerated brainstem auditory evoked potential (BAEP) responses and receive more inadequate parental bonding. Methodology/Principal Findings Children aged seven and their mothers (141 pairs) participated. BAEP was measured by summation of 1,000 waves of the electroencephalogram triggered by 75 dB click sounds. The mothers completed their Childrens Somatization Inventory (CSI) and Parental Bonding Instrument (PBI). CSI results revealed 66 (42%) children without GI symptoms (controls) and 75 (58%) children with one or more GI symptoms (GI group). The III wave in the GI group (median 4.10 interquartile range [3.95–4.24] ms right, 4.04 [3.90–4.18] ms left) had a significantly shorter peak latency than controls (4.18 [4.06–4.34] ms right, p = 0.032, 4.13 [4.02–4.24] ms left, p = 0.018). The female GI group showed a significantly shorter peak latency of the III wave (4.00 [3.90–4.18] ms) than controls (4.18 [3.97–4.31] ms, p = 0.034) in the right side. BAEP in the male GI group did not significantly differ from that in controls. GI scores showed a significant correlation with the peak latency of the III wave in the left side (rho = −0.192, p = 0.025). The maternal care PBI scores in the GI group (29 [26]–[33]) were significantly lower than controls (31 [28.5–33], p = 0.010), while the maternal over-protection PBI scores were significantly higher in the GI group (16 [12]–[17]) than controls (13 [10.5–16], p = 0.024). Multiple regression analysis in females also supported these findings. Conclusions It is suggested that children with chronic GI symptoms have exaggerated brainstem responses to environmental stimuli and inadequate parental behaviors aggravate these symptoms.

Increased sensitivity to cytosine arabinoside in human leukemia by c-raf-1 antisense oligonucleotides.

c-raf-1, a cytoplasmic serine/threonine protein kinase, plays an important role in mitogen- and damage-responsive cellular signal transduction pathways. Expression of c-raf-1 modifies cell growth, proliferation and survival. Although expression of c-raf-1 has been studied in several tumors, the role of c-raf-1 in leukemia is so far unclear. We examined the expression of c-raf-1 in the human leukemia cell lines U937 and K562, and in a cytosine arabinoside (Ara-C)-resistant cell line (K562AC) derived from K562. Expression of c-raf-1 was increased in U937 and in Ara-C-resistant K562AC cells compared with the parental cells. We then investigated whether inhibition of c-raf-1 expression by antisense oligonucleotides increases the sensitivity to Ara-C in U937 and K562AC cells. Antisense oligonucleotides for c-raf-1 inhibited expression of c-raf-1 mRNA, but did not affect cell growth and increased sensitivity to Ara-C but not to other drugs such as adriamycin, VP-16 or vincristine. These results suggest that c-raf-1 is one of the factors involved in Ara-C resistance in leukemia and lend weight to the case for development of anti-cancer therapeutics involving oncogene-targeted antisense oligonucleotides.

Enhanced Auditory Brainstem Responses in Children With Irritable Bowel Syndrome and Parental Bonding Style

G A A b st ra ct s group. Only 37% of the PPI group had documented indication for PPI use. Conclusions: SBP is common problem with cirrhotic patients. There are many risk factors associated with developing SBP, and one of these may be the use of PPIs. Our study found that the use of PPIs and lower ascitic albumin level may predispose patients to more severe infections and increase mortality. This is an important consideration when prescribing PPIs in cirrhotic patients.

Irritable Bowel Syndrome in children and neurophysiological assessment of emotion regulation

Cerebellum is involved in the motor control system to generate smooth and accurate motor command. The acquisition of the cerebellar circuit is achieved by repetitive non-declarative learning. We would like to expand the cerebellar function to thinking process, especially intuitive thinking. To verify our hypothesis, we employed Japanese-chess, “SHOGI”, and its players from trained amateur to professional player. Psychophysical experiments revealed optimal time to answer given checkmate task intuitively. Furthermore, changing rule of the SHOGI affects correct answer ratio depending to their original SHOGI experience. Then we measured cerebellar BOLD using 4T-MRI system during previously obtained condition. Their both lateral hemisphere cerebellar BOLD was selectively increased during checkmate task, not control conditions.These results imply that intuitive thinking, the answer is given within short time and semi-automatically, may use cerebellar circuitry which is acquired repetitive training. We will further investigate the analogy between cerebellar motor control and the intuition.