The tumor suppressor WARTS activates the Omi / HtrA2-dependent pathway of cell death

Drosophila tumor suppressor WARTS (Wts) is an evolutionally conserved serine / threonine kinase and participates in a signaling complex that regulates both proliferation and apoptosis to ensure the proper size and shape of the fly. Human counterparts of this complex have been found to be frequently downregulated or mutated in cancers. WARTS, a human homolog of Wts, is also known as tumor suppressor and mitotic regulator, but its molecular implications in tumorigenesis are still obscure. Here, we show that WARTS binds via its C-terminus to the PDZ domain of a proapoptotic serine protease Omi / HtrA2. Depletion of WARTS inhibited Omi / HtrA2-mediated cell death, whereas overexpression of WARTS promoted this process. Furthermore, WARTS can enhance the protease activity of Omi / HtrA2 both in vivo and in vitro. Activation of Omi / HtrA2-mediated cell death is thus a potential mechanism for the tumor suppressive activity of WARTS.     

Vitamins K1 and K2 potentiate hyperthermia by down-regulating Hsp72 expression in vitro and in vivo

Hyperthermia is used to treat various malignancies, including esophageal, stomach and rectal cancer. Since hyperthermia alone has produced limited results, much attention has been focused on combining hyperthermia with chemotherapy and on searching for substances able to sensitize tumor cells to hyperthermia-induced damage. Here, we show that vitamins K1 and K2 (VK1, VK2) inhibited the expression of heat-shock protein 72 (Hsp72) but did not affect the constitutive expression of Hsc70 or calnexin in vitro and in vivo. VK1 and VK2 sensitized A549 cells to heat-shock induced cell death, while the compounds alone had no effect on cell viability. The suppression of Hsp72 was apparently at the protein level because the mRNA expression of Hsp72 was unchanged. Moreover, the chaperone activity of Hsp72 was compromised after heat-shock when cells were pre-treated with VK2. The effect of VK2 on Hsp72 suppression, however, was also observed in normal mouse tissue after the mice were subjected to whole-body hyperthermia. To eliminate this side effect, local hyperthermia was performed on tumors in mice. The pre-treatment with VK2 potentiated the effect of local hyperthermia on tumor growth suppression. The findings here that VK1 and VK2 inhibit heat-shock-induced Hsp72 suggest their possible use as an adjuvant for hyperthermia in cancer therapy.     

High antitumor activity using intratumoral injection of plasmid DNA with mutant-type p27Kip1 gene following in vivo electroporation

In this study, we attempted to use a non-viral gene transfer system, in vivo electroporation, in oral cancer cell B88 xenografts. To evaluate this in vivo gene transfer method, the GFP gene was transfected into xenografts by electroporation. Then, the efficiency of transfection of exogenous p27Kip1 gene by electroporation was confirmed by Western blot analysis. Next, to estimate the reduction of oral cancer xenografts by this method, we measured the size of B88 xenografts in nude mice after electroporation with the wild- or mutant-type p27Kip1 gene. The growth of tumors was markedly suppressed by mutant-type p27Kip1 gene transfection by electroporation compared with transfection of wild-type p27Kip1 gene or empty vector only. Moreover, histological specimens revealed apoptotic cell death was increased in mutant-type p27Kip1-transfected tumors compared to wild-type or empty vector only. These results suggest that it is possible to transfer mutant-type p27Kip1 into oral cancer xenografts using electroporation and to suppress the growth of tumors, furthermore, it is suggested that this system might be used for oral cancer.     

Expression of cell adhesion molecules and chemokine receptors: angioinvasiveness in nasal NK/T-cell lymphoma

Sinonasal natural killer (NK)/T-cell lymphoma (NKTCL) is closely associated with Epstein-Barr virus (EBV) infection and expresses latent membrane protein (LMP)-1 and EB nuclear antigen (EBNA)-1, i.e., latency II of EBV infection. Angioinvasion by neoplastic cells is a characteristic feature of NKTCL, but its mechanism is unknown. To elucidate the molecular mechanism of angio-invasiveness in NKTCL, expression of cell adhesion molecules and chemokine receptors at mRNA and protein levels was examined using real-time PCR and immunohistochemistry in 17 NKTCL together with 10 diffuse large B-cell lymphoma (DLBL) and 9 non-neoplastic nasal mucosa as controls. EBV DNA was detected in 14 of 16 NKTCL examined, and 7 of these 14 expressed LMP-1. mRNA expression levels of integrin subunits alpha4, alpha L, alpha M, and beta2 were significantly higher in NKTCL than non-neoplastic controls. Integrin subunits alpha2 and alpha M were expressed at a significantly higher level in NKTCL with angioinvasion than those without. Expression level of alpha M was significantly higher in 7 cases of NKTCL with LMP-1 expression than 7 without. Immunohistochemistry showed expression of these molecules in NKTCL cells. These findings suggest that EBV infection might be involved in the pathogenesis of angioinvasion of NKTCL through up-regulation of alpha M by LMP-1.     

Silymarin augments human cervical cancer HeLa cell apoptosis via P38/JNK MAPK pathways in serum-free medium

Silymarin was proved to have a protective effect of UV-induced A375-S2 cell apoptosis in our previous research. In this study, its pro-apoptotic and anti-apoptotic activities on human cervical cancer (HeLa) cells in vitro were investigated. Silymarin induced HeLa cell death through both apoptotic and necrotic pathways. At low doses (below 80 micromol l-1), it induced cell apoptosis, but caused necrosis at high dose (160 micromol l-1). Silymarin induced typical chromatin condensation and nuclear fragmentation as a hallmark of apoptosis. In this case, mitochondrial Bcl-2 family, Bcl-2 and Bax, were not involved in apoptotic effects; however, silymarin-induced cell death was regulated by the activation of p38 and JNK MAPKs. We also found that pan-caspase inhibitor and caspase-3 inhibitor could not antagonise silymarin-induced apoptosis. Therefore, silymarin induced and augmented HeLa cell apoptosis through p38/JNK MAPKs in the serum-free medium.     

Gastropleural fistula due to gastric perforation after lobectomy for lung cancer

We report a case of acute gastropleural fistula due to gastric perforation after a left lower lobectomy for lung cancer. A 76-year-old male, who received a left hemicolectomy 20 years previously, came to our hospital for surgical treatment of lung cancer, which was performed uneventfully as a left lower lobectomy with combined resection of the diaphragm. On the postoperative day 2, acute dilatation of the stomach followed by gradual cardiopulmonary collapse, and then gastric perforation into the thorax occurred. The perforated stomach wall and diaphragm became paper-thin and necrotic, though the abdominal cavity was free of contamination. This life-threatening condition was treated by an emergency thoracotomy and partial gastrectomy through the thorax, as the left hemidiaphragm was remarkably elevated. An oeganoaxial torsion gastric volvulus caused by anatomic rotation following the lobectomy was speculated as the disease process, with loss of suspended tissue of the gastro-colic ligament from the left hemicolectomy being a possible predisposing factor. Such an episode is rare, however, it should be looked for during perioperative care following a lobectomy.     

Identification of genes preferentially expressed in articular cartilage by suppression subtractive hybridization

Suppression subtractive hybridization is very effective to enrich differentially expressed genes in two different tissues or cells. We therefore used the technique to identify characteristic genes expressed in rat knee joint articular cartilage as compared to rat costal cartilage. In this study, we revealed that several genes were enriched in a subtracted articular cartilage cDNA library. The most enriched gene is lubricin that is a putative key molecule for joint lubrication. The second gene is milk fat globule epidermal growth factor (EGF) factor 8, MFG-E8 whose expression has never been observed in cartilage. Other enriched genes are known to be expressed in cartilage, however their differential expressions in cartilages have not been necessarily common. The preferential expression of characteristic genes in articular cartilage would provide unique properties to the tissue. Our findings will provide a new view of articular cartilage.     

Surgical technique in endoscopic posterior septoplasty for an adult patient with choanal stenosis

The technique in endoscopic posterior septoplasty for the case of a female aged 49 with bilateral choanal stenosis is presented. This female had undergone endoscopic nasal surgery for stenosis twice before the posterior septoplasty. However, restenosis of the choanae had arisen within 2 weeks after each surgery. This patient underwent the endoscopic posterior septoplasty under general anesthesia. After removal of the cartilage and bony structures of the nasal septum, the posterior one-third of bilateral septal membranes was excised. This technique is to enlarge the choanal opening obliquely. Excellent visualization for the septoplasty using the endoscope was obtained. Sufficient patency of the choanae was achieved using this technique. There still is no restenosis of the choanae observed and the rhinomanometry shows extreme decrease of nasal airway resistance 1 year after this surgery. It is considered that endoscopic posterior septoplasty for choanal stenosis is an effective procedure with low morbidity and long-term patency.     

Genesis of the decrement of intraluminal pressure in the UES during swallowing in rabbits

The intraluminal pressure in the upper esophageal sphincter (UES) briefly decreases during swallowing. This decrement in pressure plays an important role in smooth transport of the ingested bolus from the pharynx to the esophagus. It is known that the decrement is caused by cessation of tonic activity of the cricopharyngeus (CP) muscle and also by elevation of the larynx. On the other hand, it is suspected that the recurrent laryngeal nerve (RLN) also contributes to the decrement, since our preliminary study showed for the first time that the decrement in UES pressure was much reduced after the RLN was sectioned. In the present study, we examined the genesis of the decrement of the UES pressure in anesthetized rabbits. When swallowing was elicited by repetitive electrical stimulation of the superior laryngeal nerve, the UES pressure briefly decreased and then abruptly increased. After bilateral sectioning of the RLN, the decrement of the pressure was significantly reduced, whereas the increment was little altered. Sectioning of the pharyngeal branch of the vagus nerve (X-ph) and the RLN mostly eliminated both the decrement and increment of the pressure, and abolished tonic and burst activities of the CP muscle. Electrical stimulation of peripheral end of the RLN decreased the pressure. These results indicate that the RLN and X-ph are involved in the decrement of the UES pressure during swallowing. The RLN generates the decrement by adducting the arytenoid cartilage and closing the glottis. The X-ph contributes to the decrement both by suppressing the tonic activity of the CP muscle and by regulating the laryngeal elevation.