Noriaki Sadanaga

Deregulation of the akt pathway in human cancer

Akt (protein kinase B) is a serine/threonine kinase which is a central regulator of widely divergent cellular processes including proliferation, differentiation, migration, survival and metabolism. Akt is activated by a variety of stimuli, through growth factor receptors, in phosphatidylinositol 3-kinase (PI3K)-dependent manner. Akt is also negatively regulated by the tumor suppressor phosphatase and tensin homolog deleted on chromosome 10 (PTEN). A disruption of normal Akt/PKB/PTEN signaling frequently occurs in many human cancers, which plays an important role in cancer development, progression and therapeutic resistance. Numerous studies have revealed the blockage of Akt signaling to result in apoptosis and growth inhibition of tumor cells. Therefore, this signaling pathway, including both upstream and downstream of Akt, has recently attracted considerable attention as a new target for effective cancer therapeutic strategies. In fact, many inhibitors of Akt pathway have been identified and clinical studies of some agents are ongoing. In this review, we describe Akt signaling pathway components and its cellular functions as well as the alterations in human cancers and the therapeutic approaches for targeting the Akt pathway in cancer.

Enhanced mass on contrast-enhanced breast MR imaging: Lesion characterization using combination of dynamic contrast-enhanced and diffusion-weighted MR images

To evaluate the diagnostic accuracy of a combination of dynamic contrast‐enhanced MR imaging (DCE‐MRI) and diffusion‐weighted MR imaging (DWI) in characterization of enhanced mass on breast MR imaging and to find the strongest discriminators between carcinoma and benignancy.

Advances in esophageal cancer surgery in Japan: An analysis of 1000 consecutive patients treated at a single institute

BACKGROUND In Japan, most esophageal cancers are squamous cell carcinomas, and the results of esophagectomy have improved remarkably in recent years. The object of this study was to evaluate advances in operative therapy for esophageal cancer in Japan. METHOD We evaluated mortality, morbidity, and prognosis in 1000 consecutive patients who underwent esophagectomy for esophageal cancer at a single institution in Japan. The patients were divided into 3 groups according to the period when esophagectomy was performed: Group I (n = 197), 1964-1980; group II (n = 432), 1981-1993; and group III (n = 371), 1993-2006. RESULTS The incidence of squamous cell carcinoma was 94%. The morbidity rates were 62%, 38%, and 33 %, in groups I, II, and III, respectively (P < 0.01, groups I vs II and III), and the in-hospital mortality rates were 14.2%, 5.1%, and 2.4%, respectively (P < 0.01, between each group). The 5-year overall survival rate was 30% (14%, 27%, and 46% in groups I, II, and III, respectively; P < 0.0001). Multivariate analysis revealed age, gender, depth of invasion, node metastasis, distant metastasis, curability, extent of lymphadenectomy, resectability, and the period when the operation was performed as independent prognostic factors. CONCLUSION Generally, esophagectomy has been performed safely without critical complications; however, the prognosis has improved remarkably with advances in surgical techniques and treatment modalities.

Expression of multiple cancer-testis antigen genes in gastrointestinal and breast carcinomas

Cancer-testis antigens (CTAs) such as MAGE are selectively expressed in various types of human neoplasms but not in normal tissues other than testis. This characteristic feature of CTAs makes them promising antigens for cancer-specific immunotherapy. A critical requirement for this therapy is identification of promising antigens. In this study, we investigated the expression of 6 genes recently identified by serological analysis of antigens by recombinant expression (SEREX) libraries: NY-ESO-1, LAGE-1, SCP-1, SSX-1, SSX-2, and SSX-4, in many surgical samples of gastrointestinal and breast carcinomas using reverse transcription-polymerase chain reaction. We found relatively high expression of SCP-1 (23.5%) and SSX-4 (20.6%) in gastric carcinoma, LAGE-1 (39.1%) and NY-ESO-1 (23.9%) in oesophageal carcinoma, and SCP-1 (34.1%) in breast carcinoma. We also found frequent synchronous expression with MAGE, including LAGE-1 (46.2%) in oesophageal carcinoma, SSX-4 (46.7%) in gastric carcinoma, and SCP-1 (38.3%) in breast carcinoma. Immunohistochemical analysis of the tumour samples expressing both MAGE-4 and NY-ESO-1 genes demonstrated differences in distribution between MAGE-4 and NY-ESO-1 in serial sections. We concluded that NY-ESO-1, LAGE-1, SCP-1 and SSX-4 genes may be promising candidates for cancer-specific immunotherapy in addition to MAGE, and that polyvalent cancer vaccines may be useful in cases of heterogeneous expressions of CTA genes in gastrointestinal and breast carcinomas.

Intratumoral injection of dendritic cells after treatment of anticancer drugs induces tumor‐specific antitumor effect in vivo

We investigated the in vivo antitumor effects of intratumoral (i.t.) administration of dendritic cells (DC) after low‐dose chemotherapy using cisplatin + 5‐FU. Combination of i.t. injection of DC and systemic chemotherapy induced complete rejection of the treated tumor, MC38 murine adenocarcinoma. Furthermore, the antitumor effects were also observed on a distant tumor inoculated in the contralateral flank of the animal. When 10× the number of tumor cells were inoculated, the antitumor effect of the combination of DC after chemotherapy was also confirmed and in comparison to that of DC or chemotherapy alone, thereafter contributed to a greater prolongation of survival. To analyze the mechanisms of the systemic antitumor effect generated in this system, we assessed the cytolytic activity against inoculated tumors. The cytolytic activity of effector cells from treated animals was shown to be tumor‐specific and was mainly CD8 and MHC Class‐I (p < 0.01) restricted. CD4 and MHC Class‐II treatment marginally inhibited the cytolytic activity but not significantly (p = 0.07, 0.08 respectively). The cytolysis of effector cells was enhanced more significantly by the treatment of both DC and chemotherapy, than that of either DC or chemotherapy alone. Our study suggests that the strategy of i.t. injection of DC after low‐dose chemotherapy could be a powerful weapon to treat patients with cancer in the clinical settings.

Gold nanoparticle-based colorimetric assay for cancer diagnosis

A novel gold nanoparticle (GNP)-based colorimetric assay was developed for cancer diagnosis. This system is based on the noncrosslinking aggregation mechanism with a cationic protein kinase C (PKC) alpha-specific peptide substrate, which is used as a coagulant of citrate-coated GNP with anionic surface charges. The phosphorylation of peptide substrates by PKCalpha suppressed GNP aggregation, resulting in a red color, but in the case of non-phosphorylation, the color of the GNP solution changed from red to blue, indicating particle aggregation. Moreover, a correlation between the color change of the GNP dispersions and the level of activated PKCalpha was identified from experiments using cancer cell lines, or xenografted mouse cancer and normal mouse tissues. When our system was applied to human breast cancers and normal human breast tissues, cancer tissue lysates became red in color, indicating GNP dispersion, while all lysates from normal tissue turned the GNP solution blue. MALDI-TOF MS analysis and Western blotting experiment confirmed that these different results between cancer and normal tissues reflected the difference in PKCalpha activity. This study is the first report on the application of the GNP-based colorimetric assay to the diagnosis of cancer.

Reduced tau expression in gastric cancer can identify candidates for successful Paclitaxel treatment

A recent study disclosed that breast cancer cases with low ‘tau’ expression can predict susceptibility to Paclitaxel administration. In the current study, the clinical significance of tau expression in gastric cancer cases was established by identifying candidates with Paclitaxel administration. Tissue specimens from 20 cases of in-operable or noncuratively resected gastric cancer were examined. Subsequent to the administration of 80 mg m−2 of Paclitaxel in six 3-h intravenous infusions, the clinical effectiveness of Paclitaxel was evaluated by the size of metastatic lesions with computed tomography. The status of the tau expression was determined by immunohistochemistry. Based on a previously reported classification scheme, six were classified as tau-negative expression (0, 1+) cases and 14 were classified as tau-positive expression (2+, 3+) cases. All six (100%) cases of tau-negative expression showed a favourable response (partial response or minor response) to Paclitaxel administration. However, 12 (86%) of the 14 cases of tau-positive expression showed progressive disease (n=11) or no change (n=1) after Paclitaxel administration. The serum carcinoembryonic antigen values of the six cases of tau-negative expression were markedly decreased in comparison to the 14 tau-positive cases. These data indicate that tau-negative expression can be used to select gastric cancer patients, which will favourably respond to Paclitaxel treatment.

Laparoscopy-assisted surgery: A new technique for transhiatal esophageal dissection

Esophageal dissection under laparoscopic monitoring is performed during total esophagectomy to treat patients with cervical esophageal carcinoma. Using this technique, a safe esophageal dissection can be made from the surrounding mediastinal tissues. Some of the disadvantageous consequences of a blunt dissection, including the blind maneuver, may thus be prevented and various intraoperative and postoperative complications may be avoided.

Esophagectomy in patients 80 years of age and older with carcinoma of the thoracic esophagus

BackgroundThe purpose of this study was to clarify the indications for an esophagectomy in elderly patients (especially patients over 80 years of age) with esophageal cancer.MethodsA total of 668 patients with thoracic esophageal cancer who underwent an esophagectomy by the transthoracic approach were divided into three groups according to age, namely, groups I (>80 years, n = 16), II (70–79 years, n = 158), and III (≤69 years, n = 494). In group I, surgery was only done in patients with PS 0 or 1, as well as normal cardiac and pulmonary functions.ResultsThe incidence of preoperative pulmonary risk was 16% and 7% in groups II and III, respectively (P < 0.01). The morbidity rates of group II and III were 42% and 32%, respectively (P < 0.05). Pulmonary complications occurred in 18% and 10%, respectively, and cardiovascular complications occurred in 11% and 4%, respectively (P < 0.01). In group I, the morbidity and 30-day mortality rates were 25% and 0%, respectively, and pulmonary and cardiovascular complications occurred only in one patient each (6%). No significant differences were observed in cause-specific survival.ConclusionsIn the elderly, preoperative pulmonary risk is frequently present, and careful perioperative management is needed while paying special attention to pulmonary and cardiovascular complications. However, when the indications for surgery can be strictly determined, an esophagectomy is considered a viable treatment alternative with satisfactory prognosis even in patients 80 years of age and older without any increased morbidity or mortality.

Squamous epithelial dysplasia associated with squamous cell carcinoma of the esophagus

To investigate the relationship between dysplasia and carcinoma of the esophagus, 159 cases of esophageal carcinoma without any preoperative treatment were reviewed retrospectively. There were 75 dysplastic lesions in 32 cases (20.1%). The incidence of co-existence of dysplastic lesions was 0, 58.3, 31.3, 20.8 and 11.4% in intra-epithelial, mucosal and submucosal cancers and those invading the proper muscular layer and adventitia, respectively. Thus, excluding the cases of intra-epithelial carcinoma, the less advanced the lesion, the higher the incidence of dysplasia. Epithelial dysplastic lesions were classified as 12 with mild, 33 with moderate and 30 with severe degrees of dysplasia. Although the continuity of dysplastic lesions to the areas of carcinoma was not so frequent (48.0%), it was more often encountered in severe dysplasia rather than in moderate or mild dysplasia, which suggested some relationship between the severity of dysplasia and carcinoma. In the cases with a dysplastic lesion the multiplicity of squamous cell carcinoma and the intra-epithelial spread of the main lesion were more frequently seen (P < 0.001), suggesting a multicentric occurrence of dysplastic lesions and carcinomas.