Hideki Ishihara

High expression of ubiquitin carboxy-terminal hydrolase-L1 and -L3 mRNA predicts early recurrence in patients with invasive breast cancer

The present study investigated the mRNA expression level of ubiquitin c‐terminal hydrolase (UCH)‐L1 and ‐L3 in breast cancer tissue and aimed to elucidate its association with tumor characteristics and patient prognosis. UCH‐L1 and UCH‐L3 mRNA levels in invasive breast cancer (n = 100) were determined by a real‐time polymerase chain reaction (PCR) assay and their relationship with various clinicopathological characteristics of breast tumors as well as patient prognosis were studied. UCH‐L3 mRNA level was significantly upregulated in breast cancer tissue compared to adjacent normal breast tissue (P < 0.005), and UHC‐L1 mRNA level also showed a non‐significant increase in tumor tissue compared to adjacent normal breast tissue. Both UCH‐L1 and UCH‐L3 mRNA levels were significantly higher in high histological grade tumors than in low histological grade tumors (P < 0.001 and P < 0.005, respectively). High UCH‐L1 mRNA level was significantly associated with negative estrogen receptor status (P < 0.05) and negative progesterone receptor status (P < 0.05). Patients with both UCH‐L1 and UCH‐L3 mRNA high tumors showed a significantly poorer prognosis than those in the UCH‐L1 or UCH‐L3 mRNA low group (P < 0.005). These observations that UCH‐L3 mRNA level is upregulated in breast cancer tissue, and breast tumors with both UCH‐L1 and UCH‐L3 mRNA high expression are associated with a poor prognosis, suggest the possible involvement of UCH‐L1 and UCH‐L3 in the pathogenesis and progression of breast cancer. (Cancer Sci 2006; 97: 523– 529)

Growth-inhibitory effect of adiponectin via adiponectin receptor 1 on human breast cancer cells through inhibition of S-phase entry without inducing apoptosis.

Adiponectin is one of the most important adipocytokines secreted from adipose tissue. In addition to its effects on glucose and fatty acid metabolism, it has been reported that adiponectin has a direct growth-inhibitory effect on breast cancer cells. However, it still remains to be established how adiponectin affects cell cycle and apoptosis and whether or not its inhibitory effect is mediated through adiponectin receptors. Here, we demonstrated that adiponectin treatment resulted in a significant dose-dependent growth inhibition of both MDA-MB-231 and T47D cells. In both cell lines, the G0/G1 population significantly increased after adiponectin treatment, but apoptosis was not induced. High expression of mRNA and protein of adiponectin receptor 1 was observed, but expression of adiponectin receptor 2 was very low in both cell lines. Treatment with small interference RNA against adiponectin receptor 1 significantly reduced the growth inhibition induced by adiponectin in both cell lines. Taken together, adiponectin decreases breast cancer cell proliferation by inhibiting the entry into S-phase without inducing apoptosis, and this inhibitory effect is mediated through adiponectin receptor 1.

Prediction of paclitaxel sensitivity by CDK1 and CDK2 activity in human breast cancer cells

IntroductionPaclitaxel is used widely in the treatment of breast cancer. Not all tumors respond to this drug, however, and the characteristics that distinguish resistant tumors from sensitive tumors are not well defined. Activation of the spindle assembly checkpoint is required for paclitaxel-induced cell death. We hypothesized that cyclin-dependent kinase (CDK) 1 activity and CDK2 activity in cancer cells, which reflect the activation state of the spindle assembly checkpoint and the growth state, respectively, predict sensitivity to paclitaxel.MethodsCell viability assays and DNA and chromatin morphology analyses were performed in human breast cancer cell lines to evaluate sensitivity to paclitaxel and the cell cycle response to paclitaxel. We then examined the specific activities of CDK1 and CDK2 in these cell lines and in xenograft models of human breast cancer before and after paclitaxel treatment. Protein expression and kinase activity of CDKs and cyclins were analyzed using a newly developed assay system.ResultsIn the cell lines, biological response to paclitaxel in vitro did not accurately predict sensitivity to paclitaxel in vivo. Among the breast cancer xenograft tumors, however, tumors with significantly increased CDK1 specific activity after paclitaxel treatment were sensitive to paclitaxel in vivo, whereas tumors without such an increase were resistant to paclitaxel in vivo. Baseline CDK2 specific activity was higher in tumors that were sensitive to paclitaxel than in tumors that were resistant to paclitaxel.ConclusionsThe change in CDK1 specific activity of xenograft tumors after paclitaxel treatment and the CDK2 specific activity before paclitaxel treatment are both associated with the drug sensitivity in vivo. Analysis of cyclin-dependent kinase activity in the clinical setting could be a powerful approach for predicting paclitaxel sensitivity.

Specific activity of cyclin-dependent kinase I is a new potential predictor of tumour recurrence in stage II colon cancer

Background:There are no established biomarkers to identify tumour recurrence in stage II colon cancer. As shown previously, the enzymatic activity of the cyclin-dependent kinases 1 and 2 (CDK1 and CDK2) predicts outcome in breast cancer. Therefore, we investigated whether CDK activity identifies tumour recurrence in colon cancer.Methods:In all, 254 patients with completely resected (R0) UICC stage II colon cancer were analysed retrospectively from two independent cohorts from Munich (Germany) and Leiden (Netherlands). None of the patients received adjuvant treatment. Development of distant metastasis was observed in 27 patients (median follow-up: 86 months). Protein expression and activity of CDKs were measured on fresh-frozen tumour samples.Results:Specific activity (SA) of CDK1 (CDK1SA), but not CDK2, significantly predicted distant metastasis (concordance index=0.69, 95% confidence interval (CI): 0.55–0.79, P=0.036). Cutoff derivation by maximum log-rank statistics yielded a threshold of CDK1SA at 11 (SA units, P=0.029). Accordingly, 59% of patients were classified as high-risk (CDK1SA ⩾11). Cox proportional hazard analysis revealed CDK1SA as independent prognostic variable (hazard ratio=6.2, 95% CI: 1.44–26.9, P=0.012). Moreover, CKD1SA was significantly elevated in microsatellite-stable tumours.Conclusion:Specific activity of CDK1 is a promising biomarker for metastasis risk in stage II colon cancer.

Novel mechanism of reduced proliferation in ovarian clear cell carcinoma cells: Cytoplasmic sequestration of CDK2 by p27

OBJECTIVE Ovarian clear cell carcinoma (CCC) carries a poor prognosis because of its insensitivity to chemotherapy. We previously found an association between reduced proliferation of CCC and chemoresistance; here we investigated the mechanism of the reduced proliferation. METHODS We assessed cell cycle function by measuring the activity of cyclin-dependent kinases (CDKs) and the protein expression of cyclins, the CDK inhibitors, and p53 in 22 ovarian cancer cell lines and 60 human ovarian cancer specimens. We examined the cellular location of p27, p27 phosphorylated at threonine 157 (p27(Thr157)), and CDK2 protein by confocal microscopy and western blotting. We tested the effect of the inhibitor of phosphatidylinositol-3-kinase (PI3K) and small interfering RNA against p27 (si-p27) in two CCC cell lines (RMG-I, SMOV-2). RESULTS CCC cells had lower CDK2 activity and higher p27 expression than serous adenocarcinoma (SA) cells. Low CDK2 activity correlated with high p27 protein expression. p27(Thr157) sequestered CDK2 in the cytoplasm, but PI3K inhibitor or si-p27 maintained CDK2 in the nucleus and restored its activity. In human specimens, CDK2 was mostly in the cytoplasm and was spatially associated with p27; CDK2 activity was lower in the CCC than in the SA specimens. si-p27 enhanced the cytotoxic effect of cisplatin, doxorubicin, and gemcitabine in both RMG-I cells and SMOV-2 cells. CONCLUSIONS Reduced CDK2 activity via the cytoplasmic sequestration of CDK2 by p27(Thr157) may contribute to suppression of CCC proliferation. A prospective study is needed to determine whether the cytoplasmic sequestration of CDK2 results in the chemoresistance of CCC.

CDK1 and CDK2 activity is a strong predictor of renal cell carcinoma recurrence

BACKGROUND In renal cell carcinoma (RCC), the prediction of metastasis via tumor prognostic markers remains a major problem. The objective of our study was to evaluate the efficacy of cyclin-dependent kinase (CDK)1 and CDK2 activity as a prognostic marker in human RCC. METHODS Surgical specimens were obtained from 125 patients with RCC without metastasis. Protein expression and kinase activity of CDKs were analyzed using a newly developed assay system named C2P (Sysmex, Kobe, Japan). We then examined the specific activities (SAs) of CDK1 and CDK2 and calculated CDK2SA-CDK1SA ratio in RCC. Also, risk score (RS) was examined. RESULTS A total of 125 cases were tested, though 34 cases were excluded because of low sample quality (25 cases) and assay failure (9 cases). In total, 91 cases were analyzed. They included 68 male and 23 female patients, ranging in age from 19 to 83 years. At a median follow-up of 36 months (1-109M), tumor with low CDK2SA-CDK1SA ratio showed significantly better 5-year recurrence-free survival than those with high CDK2SA-CDK1SA ratio (88.7% vs. 54.7%, P = 0.00141). Also, RS enabled the classification of RCCs into high-risk and low-risk groups, and patients with tumors classified as low RS showed better recurrence-free survival than patients with tumors with high RS (88.7% vs. 54.7%, P = 0.0141). CONCLUSION CDK1SA of tumors and the CDK2SA are both associated with recurrence and prognosis. IMPACT CDK-based risk demonstrated is strongly associated with clinical outcome. CDK-based risk should be an accurate system for predicting recurrence and survival for planning follow-up.

Recurrence risk score based on the specific activity of CDK1 and CDK2 predicts response to neoadjuvant paclitaxel followed by 5-fluorouracil, epirubicin and cyclophosphamide in breast cancers

BACKGROUND We established the cell cycle profiling (C2P) assay for specific activity (SA; activity/expression) of cyclin-dependent kinases (CDKs). C2P risk score (C2P-RS) based on CDK1 and CDK2 SAs was significantly associated with relapse in breast cancer (BC). This study was conducted to investigate the predictive value of C2P-RS for neoadjuvant chemotherapy (NAC). PATIENTS AND METHODS Among 124 eligible patients, 122 were treated with weekly paclitaxel followed by 5-fluorouracil, epirubicin and cyclophosphamide (P-FEC) and 2 were treated with paclitaxel monotherapy. C2P-RS was determined via C2P using frozen biopsy samples before NAC. RESULTS Negative estrogen receptor (ER), negative progesterone receptor (PR), positive human epidermal growth factor receptor 2 (HER2), high Ki-67 expression and intermediate + high C2P-RS were significantly associated with high pathological complete response (pCR) rates compared with positive ER (30% versus 9%), positive PR (25% versus 6%), negative HER2 (34% versus 11%), low Ki-67 expression (24% versus 7%) or low C2P-RS (24% versus 9%), respectively. The combination of C2P-RS and Ki-67 had a stronger impact on pCR than each parameter alone, and a multivariate analysis showed that the combination was an independent predictor of pCR (odds ratio 3.3, 95% confidence interval 1.1-9.5). CONCLUSIONS C2P-RS was significantly associated with pCR after P-FEC and may be a useful predictor for chemotherapy in BCs.

Validation study of the prognostic value of cyclin-dependent kinase (CDK)-based risk in Caucasian breast cancer patients

In a Japanese study, cyclin-dependent kinase (CDK) based risk determined by CDK 1 and 2 activities was associated with risk of distance recurrence in early breast cancer patients. The aim of our study was to validate this risk categorization in European early breast cancer patients. We retrospectively analyzed frozen breast cancer specimens of 352 Dutch patients with histologically confirmed primary invasive early breast cancer. CDK-based risk was determined in tumour tissues by calculating a risk score (RS) according to kinases activity and protein mass concentration assay without the knowledge of outcome. Determination of CDK-based risk was feasible in 184 out of 352 (52%) tumours. Median follow-up of these patients was 15 years. In patients not receiving systemic treatment, the proportions of risk categories were 44% low, 16% intermediate, and 40% high CDK-based risk. These groups remained significant after univariate and multivariate Cox-regression analysis. Factors associated with a shorter distant recurrence-free period were positive lymph nodes, mastectomy with radiotherapy, and high CDK-based risk. There was no significant correlation with overall survival (OS). CDK-based risk is a prognostic marker of distance recurrence of patients with early breast cancer. More validation would be warranted to use of CDK-based risk into clinical practice.

Glycolipid of human pancreatic cancer; the appearance of neolacto-series (type 2 chain) glycolipid and the presence of incompatible blood group antigen in tumor tissues

Glycolipid isolated from normal and cancerous human pancreatic tissues were characterized chemically and immunologically. The major neutral glycolipids in both normal and cancerous tissues were composed of globo-series glycolipids and lacto-series glycolipids. The mole percentage of fucolipids in the total neutral glycolipids of normal tissues was 20-40%, and in general the fucolipids corresponded to blood group glycolipids related to the patients blood group, however, in cancerous tissues the amount of these fucolipids was decreased. Immunostaining revealed that normal tissues contained only lacto-series (type 1 chain) glycolipids. In contrast, cancerous tissues contained the neolacto-series (type 2 chain) glycolipids as well as the lacto-series glycolipids. Incompatible blood group antigens, A active glycolipids in a blood type O patient and B active glycolipids in a blood type A patient, were also detectable in the neutral glycolipid fractions of the pancreatic cancer tissues.

Prognostic importance of CDK4/6-specific activity as a predictive marker for recurrence in patients with endometrial cancer, with or without adjuvant chemotherapy.

Background:Pathologically low-risk endometrial cancer patients do not receive postoperative treatment; however, 10–15% of these patients show recurrence with poor prognosis. We evaluated the clinical importance of cyclin-dependent kinase 4/6 (CDK4/6) activity, and its significance as a novel biomarker for the prognosis and chemo-sensitivity of endometrioid endometrial carcinoma (EEC).Methods:Cyclin-dependent kinase 4/6 expression and enzyme activity in 109 tumour samples from patients with EEC were examined with a cell-cycle profiling (C2P) assay. CDK4/6-specific activity (CDK4/6SA) was determined, and its relationship with clinicopathological factors and expression of Ki-67 was analysed.Results:CDK4/6-specific activity was significantly correlated with Ki-67 (P=0.035), but not with any other clinicopathological characteristics. CDK4/6SA was significantly higher (P=0.002) in pathologically low-risk patients (not receiving adjuvant chemotherapy, n=74) than in intermediate- or high-risk patients (receiving adjuvant chemotherapy, n=35). In addition, patients with high CDK4/6SA (>3.0) showed significantly (P=0.024) shorter progression-free survival (PFS) than those with low CDK4/6SA (<3.0). Although Ki-67 expression itself was not a marker for prognosis, the combination of high CDK4/6SA and high Ki-67 expression (>15%) was robustly associated with shorter PFS (P=0.015), and this combination was an independent poor prognostic factor in the low-risk group. Inversely, in the intermediate-/high-risk group, patients with high CDK4/6SA had a tendency of a more favourable prognosis compared with patients with low CDK4/6SA (P=0.063).Conclusions:CDK4/6-specific activity can be used as a biomarker to predict prognosis and, possibly, chemo-sensitivity. The combination of Ki-67 expression might strengthen the clinical usefulness of CDK4/6SA as a biomarker.