Hidetoshi Akita

Cell-cycle-dependent and ATM-independent expression of human Chk1 kinase.

Checkpoint genes cause cell cycle arrest when DNA is damaged or DNA replication is blocked. Although a human homolog of Chk1 (hChk1) has recently been reported to be involved in the DNA damage checkpoint through phosphorylation of Cdc25A, B, and C, it is not known at which phase(s) of the cell cycle hChk1 functions and how hChk1 causes cell cycle arrest in response to DNA damage. In the present study, we demonstrate that in normal human fibroblasts (MJ90), hChk1 is expressed specifically at the S to M phase of the cell cycle at both the RNA and protein levels and that it is localized to the nucleus at this time. hChk1 activity, as determined by phosphorylation of Cdc25C, is readily detected at the S to M phase of the cell cycle, and DNA damage induced by UV or ionizing radiation does not enhance the expression of hChk1 or its activity. Furthermore, hChk1 exists in an active form at the S to M phase in fibroblasts derived from patients with ataxia telangiectasia (AT) which lack the functional AT mutated (ATM) gene product, suggesting that hChk1 expression is independent of functional ATM. Taken together with the findings that phosphorylation of Cdc25C on serine 216 is increased at the S to M phase, it is suggested that at this particular phase of the cell cycle, even in the absence of DNA damage, hChk1 phosphorylates Cdc25C on serine 216, which is considered to be a prerequisite for the G2/M checkpoint. Thus, hChk1 may play an important role in keeping Cdc25C prepared for responding to DNA damage by phosphorylating its serine residue at 216 during the S to M phase.

Induction of KAI-1 expression in metastatic cancer cells by phorbol esters

KAI-1 is a tumor suppressor gene whose down-regulation has been shown to be associated with the development of metastases of cancer cells. Here, we demonstrated that KAI-1 expression was induced by activating protein kinase C even in metastatic prostate cancer cell lines in which its expression was significantly down-regulated. KAI-1 expression was enhanced in a dose-dependent manner by PMA, and its induction is at least in part due to transcriptional activation. Pretreatment with calphostin C abrogated its induction by PMA. Our findings may provide useful information for developing a novel drug capable of inducing KAI-1 expression and thereby inhibiting metastasis.

Identification and characterization of Nek6 protein kinase, a potential human homolog of NIMA histone H3 kinase

In Aspergillus nidulans, the kinase activity of NIMA (never in mitosis, gene A) is critical for the initiation of mitosis. NIMA regulates mitotic chromatin condensation through phosphorylation of histone H3 at serine 10. In the present study, we identified human Nek6 (hNek6), a member of the mammalian NIMA-related kinases. The predicted hNek6 protein is comprised of 338 amino acids. Northern blot analysis revealed that hNek6 transcripts are ubiquitously expressed with the highest expression found in the heart and skeletal muscle. Lower cell cycle-dependent expression of hNek6 transcripts was observed in the early G1 phase. GFP-fused hNek6 protein showed both nuclear and cytoplasmic localizations in HeLa cells. Fluorescence in situ hybridization using full-length hNek6 cDNA as a probe showed that the hNek6 gene is localized to human chromosome 9q33-34, a region at which the loss of heterozygosity is associated with transitional cell carcinomas. Importantly, recombinant hNek6 protein produced in insect cells effectively phosphorylated histones H1 and H3, but not casein. Thus, these results suggest that, unlike other mammalian NIMA-related kinases, Nek6 is a mitotic histone kinase which regulates chromatin condensation in mammalian cells.

Immunohistochemical evaluation of p53, proliferating cell nuclear antigen (PCNA) and bcl-2 expression during bacillus Calmette-Guerin (BCG) intravesical instillation therapy for superficial bladder cancers.

Abstract Bacillus Calmette-Guerin (BCG) immunotherapy for superficial bladder cancer is now widespread, but non-effective cases are not uncommon and it has yet to be clarified why this is the case. In an attempt to cast light on this problem, we evaluated differences between effective and non-effective cases immunohistochemically using p53, proliferating cell nuclear antigen (PCNA), and bcl-2 antibodies. Between March 1988 and March 1996 a total of 79 superficial bladder cancer patients were treated with BCG intravesical instillation therapy after transurethral resection of bladder tumor (TUR-Bt). Of these, 19 demonstrated recurrence after the initial treatment. From the 60 remaining patients without recurrence, we randomly chose 19 additional cases and evaluated both series for p53, PCNA and bcl-2 immunohistochemical staining using formalin-fixed, paraffin-embedded tissues. For the recurrent cases, material taken prior and subsequent to BCG therapy was available for 17 of the 19 patients. Positive staining for p53 was noted for 42.1% (8/19) of both recurrent and non-recurrent cases, without any difference between the two. The rates for PCNA and bcl-2 were 52.6% (10/19) and 47.4% (9/19) in recurrent, and 36.8% (7/19) and 78.9% (15/19) in non-recurrent cases, respectively. Thus, there was a significant difference for lower incidences of bcl-2 in recurrent cases (P=0.044). Values for p53 and bcl-2 were respectively 47.1% (8/17) and 41.2% (7/17) pre-treatment, and 52.9% (9/17) and 35.3% (6/17) post-treatment in the recurrence group. In contrast to the similarity in these results, PCNA positive cases were 52.9% (9/17) pre-treatment and 17.6% (3/17) post-treatment. These data suggest that there are differences between BCG-sensitive and BCG-resistant bladder cancers in terms of bcl-2 expression.

Evaluation of operative complications related to laparoscopic radical prostatectomy.

Objectives:  In this decade, there have emerged many alternatives for the therapy of localized prostate cancer, such as brachytherapy, intensity modulated radiation therapy, high intensity focused ultrasound, and retropubic radical prostatectomy. In this retrospective study, we reviewed cases of complications related to laparoscopic radical prostatectomy (LRP) from our institution only, and we evaluated whether this procedure was minimally invasive or not.

Cystic Lymphangioma of Retroperitoneum and Groin

We report a case of cystic lymphangioma of the retroperitoneum and groin. A 38-year-old male was referred to our hospital due to a right inguinal mass without tenderness. CT, MRI revealed retroperitoneal mass and inguinal mass. Biopsy of the inguinal mass was performed. The lesion was multicystic, and adherent to the surrounding tissue. Pathological examination revealed lymphangioma.

Endoscopic injection of Teflon for correction of primary vesicoureteral reflux in children.

Background: Treatment of vesicoureteral reflux by endoscopic injection of Teflon paste has recently demonstrated a good success rate. This report describes our experience in treating vesicoureteral reflux in children with particular reference to follow‐up data.

The efficacy of a serum carboxyterminal pyridinoline cross-linked telopeptide of type I collagen as a quantitative screening marker for bone metastases in patients with urological malignancies

In order to ascertain whether carboxyterminal pyridinoline cross-linked telopeptide of type I collagen (ICTP) might be useful as a serum screening parameter for bone metastases from non-prostate urological malignancies as well as prostate cancers, as series of 210 patients were examined. In addition to ICTP, serum alkaline phosphatase (ALP) and also prostate specific antigen (PSA) in the prostate cancer cases were assayed using commercial kits. The areas under the receiver operating characteristic (ROC) curves were 0.7846 for ICTP (cut-off point 9.6 microg/l), 0.8304 for ALP in prostate cancer cases, and 0.8278 for ICTP (cut-off point 10.6 microg/l), and 0.7139 for ALP in non-prostate cancer cases. While significance was only observed for ICTP and PSA in prostate cancer cases, borderline significance was also evident with ICTP for non-prostate malignancies, and with ALP for prostate cancer case. The results suggest that serum ICTP may be useful in combination with ALP as a quantitative clinical marker for low cost screening for bone metastases in patients with all types of urological malignancies.

Feasibility of a novel extraperitoneal two‐port laparoendoscopic approach for radical prostatectomy: An initial study

The aim of this study was to describe the surgical technique and to report the early outcomes of an original extraperitoneal two‐port laparoendoscopic approach for radical prostatectomy. A total of 22 consecutive patients diagnosed with early‐stage prostate cancer (cT1c, cT2N0) were operated on and included in this analysis. A multichannel port with three 5‐mm trocars, providing easier instrument handling, was inserted extraperitoneally through a 2.5‐cm lower umbilical “U” incision. An additional 12‐mm port was inserted into the left fossa to allow an adequate working angle to facilitate the most critical steps of the surgical procedures. The operation was successfully completed in all patients; one patient required an additional 5‐mm port to control bleeding. The median operation time was 259 min (range 207–453 min), and the fluid loss, including urine and blood, was 946 mL (range 257–1821 mL). The median Foley catheter indwelling period was 6 days (range 3–11 days) after surgery. No intraoperative complications occurred. Judging from this initial trial, this procedure can be safely carried out if the surgeon is familiar with conventional five‐port laparoscopic radical prostatectomy.

Neoadjuvant hormonal therapy is a feasible option in laparoscopic radical prostatectomy

BackgroundFew reports can be found in the literature with respect to the impact of neoadjuvant hormonal therapy (NHT) on operative parameters on laparoscopic radical prostatectomy (LRP) in a large study. The aim of this study was to evaluate the safety and efficacy of NHT prior to LRP for locally confined prostate cancer.MethodsFrom January 2004 to September 2009, 342 patients undergoing LRP were analyzed, specifically comparing 72 patients who received NHT to 270 who did not. All patients were in clinical stage T2 and nerve sparing LRP were not included.ResultsThe mean patient age, preoperative prostate specific antigen (PSA), clinical stage, and biopsy Gleason grade were similar for the NHT and the non-NHT LRP groups. The median blood loss and the median operative time were also similar. There were no differences in the intraoperative complication rate of rectum injury, blood transfusion, and open surgery conversion. The positive surgical margin rate was significantly improved in NHT patients. Moreover, PSA recurrence within two years was significantly less in long-term NHT than in non-NHT patients.ConclusionsLRP was shown as a safe and efficacious procedure in patients who have received NHT. Perioperative morbidity of NHT patients undergoing LRP appears equivalent to non-NHT patients, with lower positive surgical margin, and PSA recurrence rate.