Class III beta-tubulin, a marker of resistance to paclitaxel, is overexpressed in pancreatic ductal adenocarcinoma and intraepithelial neoplasia

AIMS

Class III beta-tubulin (TUBB3) reduces microtubule stability and confers resistance to microtubule-stabilizing taxanes, including paclitaxel and docetaxel. Pancreatic ductal adenocarcinomas show limited responsiveness to taxanes, but little is known of the underlying mechanisms. The aim of this study was to examine TUBB3 expression in pancreatic cancer cell lines, invasive pancreatic adenocarcinoma and pancreatic intraepithelial neoplasia (PanIN).

METHODS AND RESULTS

Reverse transcriptase-polymerase chain reaction and Western blot were used to study TUBB3 expression in pancreatic cancer cell lines. Immunohistochemistry was employed to assess TUBB3 in pancreatic cancer specimens, including 75 invasive adenocarcinomas and 41 PanIN precursor lesions. TUBB3 was undetectable in non-neoplastic ducts of the pancreas. In contrast, the vast majority (78-93%) of pancreatic ductal adenocarcinomas demonstrated either diffuse or focal TUBB3 expression. TUBB3 was found to increase progressively in PanIN lesions from 3/16 of PanIN-1 (19%), 5/17 of PanIN-2 (29%) to 5/8 of PanIN-3 lesions (63%).

CONCLUSIONS

TUBB3 is expressed in most pancreatic ductal adenocarcinomas, possibly accounting for the suboptimal response of these tumours to microtubule-stabilizing agents. Up-regulation of TUBB3 in PanIN lesions suggests that microtubule dysfunction is an early feature of this disease. TUBB3 immunohistochemistry could potentially help identify pancreatic cancer patients lacking TUBB3 expression who might benefit from taxane therapy.

Significance of nerve growth factor overexpression and its autocrine loop in oesophageal squamous cell carcinoma

Nerve growth factor (NGF) is overexpressed not only in nervous system, but also in several types of cancers. However, the role of NGF in oesophageal squamous cell carcinoma (OESCC) remains unclear. Here, we show the first evidence of NGF-TrkA autocrine loop and clinical significance of NGF overexpression in OESCC. Immunohistochemical study of 109 OESCC specimens revealed that NGF overexpression, found in 63 out of 109 patients (57.8%), was associated with lymph node metastasis, distant metastasis, higher TNM stage, poorer tumour differentiation, and poorer survival. NGF overexpression was also associated with strong expression of TrkA and negative expression of low-affinity neurotrophin receptor (p75NTR). Semiquantitative reverse transcription–polymerase chain reaction (RT–PCR) of 19 surgical specimens showed upregulation of NGF mRNA in 17 out of 19 (89%) patients. All five OESCC cell lines tested in vitro secreted detectable NGF in enzyme-linked immunosorbent assay, and expressed TrkA and p75NTR on RT–PCR and Western blot. The motility of HSA/c, one of the OESCC cell lines overexpressing NGF, was significantly decreased by either neutralising anti-NGF antibody, an inhibitor of TrkA, or NGF-small interfering RNA in transwell migration assay. Our findings suggest that NGF is of potential interest not only as a prognostic factor, but also as a novel therapeutic target in OESCC.

Growth inhibition through activation of peroxisome proliferator-activated receptor gamma in human oesophageal squamous cell carcinoma

Peroxisome proliferator-activated receptor gamma (PPARgamma) heterodimerises with retinoid X receptor alpha (RXRalpha) and is thought to be a novel therapeutic target for human malignancies. We evaluated the ability of troglitazone (TRO) alone or in combination with 9-cis retinoic acid (9CRA), ligands of PPARgamma and RXRalpha, respectively, to inhibit the growth of oesophageal squamous cell carcinoma (OSCC). All 10 tested OSCC cell lines of a KYSE series expressed PPARgamma and RXRalpha at both the mRNA and protein levels. In four tested cell lines, TRO inhibited growth, and a synergistic effect was observed with simultaneous 9CRA application. In KYSE 270 cells, a luciferase reporter assay showed that the simultaneous application of TRO and 9CRA to the cells increased the relative luciferase activity approximately 20-fold compared with the controls without TRO or 9CRA application. In this cell line, flow cytometry demonstrated that combined treatment with TRO and 9CRA greatly increased the sub-G1 phase, and Hoechst 33342/propidium iodide (PI) staining showed that apoptotic cell death was mainly induced through ligand treatment. In addition, implanted tumours in nude mice showed significant inhibition of tumour growth when treated with TRO. These results suggest that the PPARgamma/RXRalpha heterodimer may be a new therapeutic target for OSCC.

Human gastrinoma cells express calcium-sensing receptor

The intravenous calcium injection test has been reported to be useful for the diagnosis of gastrinoma. However, the mechanism underlying calcium-evoked gastrin release is not fully understood. We investigated the mechanism of calcium-stimulated gastrin release from gastrinoma cells in vitro with a particular focus on the calcium-sensing receptor (CaR). Human gastrinoma cells were taken from mechanically minced gastrinoma tissues obtained at surgery. In the perifusion system, high [Ca2+]o induced gastrin release from gastrinoma cells. As [Ca2+]o increased, [Ca2+]i rapidly increased, as monitored by fluorometry. The response was not inhibited by nifedipine, a blocker of the voltage-dependent calcium channel. Reverse transcriptase-polymerase chain reaction and subsequent Southern blot hybridization revealed the presence of the CaR gene in human gastrinoma tissues. Moreover, the expression of CaR in gastrinoma tissues was confirmed by immunohistochemistry. Our results demonstrated that CaR was expressed in human gastrinoma cells and could be involved in the mechanism of calcium-evoked gastrin release.

Ligands for peroxisome proliferator-activated receptor gamma inhibit growth of pancreatic cancers both in vitro and in vivo

Peroxisome proliferator-activated receptor gamma (PPARgamma) is expressed largely in adipose tissues and plays an important role in adipocyte differentiation. Several studies have recently shown that ligands of PPARgamma could lead to growth inhibition in some malignancies. In our study, we focused on pancreatic cancers, because the prognosis of advanced pancreatic cancer has not significantly improved due to its resistance to various chemotherapeutic regimens, so that a novel strategy should be required. We show here that PPARgamma is expressed in 5 pancreatic cancer cell lines detected in both mRNA and protein level as well as in human primary and metastatic pancreatic carcinomas examined by immunohistochemical studies. A specific ligand of PPARgamma, troglitazone, led to G1 accumulation with the increase in p27(Kip1), but not p21(Waf1/Cip1) and inhibited cellular proliferation in a pancreatic cancer cell line, Panc-1. The overexpression of PPARgamma in a pancreatic cancer cell line, KMP-3, caused lipid accumulation, which suggested cell growth in some cancers might be inhibited, at least in part, through terminal differentiation in the adipogenic lineage. In addition, implanted Panc-1 tumors in nude mice showed significant inhibition of tumor growth, when treated with pioglitazone, another specific ligand of PPARgamma. Our results suggest that ligands of PPARgamma may be a novel therapeutic agent for the treatment of pancreatic carcinomas.

Gene expression profiling in human esophageal cancers using cDNA microarray

Human esophageal cancer cell lines and human esophageal cancer tissues were profiled on cDNA microarrays. In esophageal cancer cell lines, KYAE and OE-33 (adenocarcinomas) were distinguished from KYSE series (squamous cell carcinomas). Although SK-GT-4 and TE7 were derived from adenocarcinomas, they had a comparatively similar expression profile to the KYSE series. A set of genes whose expression commonly either increased or decreased in cancer cell lines was identified. Genes that were characteristically expressed in KYAE and OE-33 were also identified. The gene expression profiles of cancer tissues (CTs) were remarkably different from those of the cancer cell lines (CCLs). Notable differences between CCLs and CTs were observed in matrix metalloproteinases, plasminogen activator, collagens, paxillin, and thrombospondin 2, etc., whose expression was not increased in CCLs but increased in CTs. Twenty-three genes were extracted to categorize patients according to their prognoses, and clustering analyses, using these genes, were performed successfully.

Expression of angiogenic factors and apoptotic factors in leiomyosarcoma and leiomyoma

Angiogenesis is essential for tumor growth and metastasis. Some angiogenic factors, such as vascular endothelial growth factor (VEGF), platelet-derived endothelial cell growth factor (PD-ECGF), transforming growth factor-alpha (TGF-alpha) and basic fibroblast growth factor (bFGF) are involved in increased angiogenic activity and disease progression in many carcinomas. However, there is little information regarding the association between angiogenic factors and leiomyosarcoma. Although there are abundant vessels in the sarcoma which enable it to easily receive nutrition and medicinal components, chemotherapy cannot effectively treat leiomyosarcoma. This means the resistance to anticancer drugs in leiomyosarcoma is very strong. However, the resistant mechanism is still unclear. In this study, expressions of VEGF, PD-ECGF, TGF-alpha, bFGF, intratumoral microvessel density (IMVD), and p53, Bcl-2 and Bax were examined by immunohistochemistry in 30 patients with leiomyosarcoma and 21 patients with leiomyoma. With regard to angiogenesis, PD-ECGF and TGF-alpha were closely associated with an increase in IMVD (p=0.012, 0.0196, respectively), and VEGF and PD-ECGF were significantly expressed in leiomyosarcoma compared with leiomyoma (p=0.041, 0.041, respectively). Although p53 expression in leiomyosarcoma was significantly higher than in leiomyoma (p=0.016), the frequency of p53 positivity was not so high (47%). On the other hand, the ratio of Bcl-2/Bax in leiomyosarcoma was significantly higher than that in leiomyoma (p=0.033). The findings of this study suggest that in leiomyosarcoma, angiogenic factors, such as PD-ECGF, VEGF and TGF-alpha expression may be involved in tumor angiogenesis, and the frequently high ratio of Bcl-2/Bax and expression of p53 gene mutation might be related to chemoresistance mechanism.

Progression of esophageal carcinoma by loss of EGF-STAT1 pathway

PURPOSE

In only a very limited number of cultured cell lines, epidermal growth factor (EGF), a potent mitogen for many kinds of cells, was shown to activate STAT1 (signal transducer and activator of transcription 1) protein, which can transmit signals that cause cell growth arrest and apoptosis. The purpose of this work is to elucidate the physiologic and/or pathological significance of this EGF-STAT1 pathway.

MATERIALS AND METHODS

A series of cultured cell lines that had been established from surgical specimens of esophageal squamous cell carcinoma was studied for the existence of the EGF-STAT1 pathway. Normal esophageal squamous epithelial cells either explanted from non-neoplastic portions of surgically removed human esophageal tissue or in bovine esophageal epithelium in situ were examined as well.

RESULTS

EGF treatment leads to a strong growth arrest in three of the 30 esophageal squamous cell carcinoma cell lines. STAT1 was found to be activated by EGF in the three cell lines but not in the others. EGF can also activate STAT1 in cultured normal esophageal squamous epithelial cells. STAT1 is at the activated state in the basal cell layer of the bovine esophageal epithelium. Notably, patients who had harbored the cancer cells with the EGF-STAT1 pathway had a dramatically better prognosis.

DISCUSSION

The EGF-STAT1 pathway may be intrinsic to esophageal epithelial lineage of cells and is lost in a considerable fraction of the carcinomas. This loss appears to cause a significantly more malignant clinical course. These findings may point out a critical step in the progression of esophageal cancer and could lead to the development of useful clinical applications.

Curative resection of microgastrinomas based on the intraoperative secretin test

The intravenous secretin injection test (secretin test) has been used for the differential diagnosis of gastrinoma. In this study we report that the intraoperative secretin test (IOS test) is also useful for determining the extent of curability in patients with Zollinger-Ellison syndrome (ZES). Twelve patients with ZES underwent surgical exploration and the IOS test. The results of the IOS test were obtained by rapid radioimmunoassay of the serum gastrin level (IRG) within 60 minutes. The test was diagnosed as negative when the maximum increase of serum IRG was less than 80 pg/ml and also less than 20% of the basal serum IRG level. Three of the twelve patients underwent pancreatoduodenectomy (PD), and two patients underwent distal pancreatectomy. Extirpation of duodenal tumors with dissection of regional lymph nodes was performed in seven patients. In two of the seven patients the IOS test remained positive after extirpation of the duodenal tumors and the dissection of regional lymph nodes. In one patient PD was performed on the basis of the positive results, and the IOS test became negative after PD. In the other patient, two tiny metastatic liver tumors were identified and were resected, but the IOS test did not become negative. We closed the abdomen in 11 patients when we obtained negative results from the IOS test. The results of the IOS test were almost identical to the data obtained by the standard assay postoperatively. The serum IRG levels of all but one patient fell to the normal level, and the secretin test became negative postoperatively. The IOS test is thus useful and indispensable for curative resection of microgastrinomas in patients with ZES.

PTEN/MMAC1 expression in esophageal squamous cell carcinomas

The PTEN/MMAC1 gene at 10q23.3 is a novel tumor suppressor gene candidate. Various kinds of tumors have mutations in this gene. However, in some cancers PTEN/MMAC1 gene may be inactivated by mechanisms other than gene deletion and mutation, including promoter methylation or translational modification. The aim of this study was to determine whether there are abnormalities in the expression of PTEN/MMAC1 gene in esophageal cancer. Reverse transcription polymerase chain reaction and western blot were used to examine PTEN/MMAC1 expression in human esophageal squamous cell lines and normal cultured esophageal epithelial cells. Immunohistochemical staining was carried out to detect PTEN/MMAC1 expression in surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. All 30 esophageal cancer cell lines (KYSE series) and normal cultured esophageal epithelial cells expressed PTEN/MMAC1 mRNA. Western blot analysis confirmed that all the cell lines expressed PTEN/MMAC1 protein and there was no difference in expression level. Immunohistochemical study showed that the PTEN/MMAC1 protein was localized dominantly in the cytoplasm and strongly stained in all 42 surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. PTEN/MMAC1 is rarely associated with esophageal squamous cell carcinoma carcinogenesis.

TGF-alpha as well as VEGF, PD-ECGF and bFGF contribute to angiogenesis of esophageal squamous cell carcinoma

It has been demonstrated that vascular endothelial growth factor (VEGF) is associated with tumor progression as an angiogenic factor in esophageal squamous cell carcinoma (SCC)s. However, the role of other angiogenic factors such as transforming growth factor-alpha (TGF-alpha), platelet-derived endothelial cell growth factor (PD-ECGF), and basic fibroblast growth factor (bFGF) are still unknown in esophageal SCCs. In this study, we detected the expression of VEGF, TGF-alpha, PD-ECGF and bFGF in tissue specimens from 96 patients with SCC of the esophagus by immunohistochemical staining. To evaluate angiogenesis, endothelial cells were stained immunohistochemically and microvessel density (MVD) was counted in 24 cases. The positive rates for VEGF, TGF-alpha, PD-ECGF and bFGF were 65% (62/96), 67% (64/96), 66% (63/96), and 49% (47/96), respectively. Only TGF-alpha expression had a strong correlation with the average MVD (p=0.0059). However, the MVD increased as the number of positive factors for these 4 factors increased (p=0.0023). The expression of all of these factors significantly correlated to the depth of tumor invasion, and lymph node metastasis. Finally, survival analysis of the patients revealed that VEGF, TGF-alpha, and PD-ECGF were significant prognostic factors. However, multivariate analysis revealed that these factors were not prognostic. Thus, we suggest that TGF-alpha as well as VEGF, PD-ECGF and bFGF may be associated with angiogenesis, and the progression and metastasis of esophageal squamous cell carcinoma.

Histological response of cisplatin predicts patients' survival in oesophageal cancer and p53 protein accumulation in pretreatment biopsy is associated with cisplatin sensitivity

The aim of this study was to evaluate whether cisplatin sensitivity relates to patient's prognosis in oesophageal squamous cell carcinoma and to find a useful chemosensitivity molecular marker. 59 oesophageal squamous cell carcinoma (SCC) patients received cisplatin 30 mg/m2/week treatment of two to five cycles, followed by oesophagectomy. We analysed retrospectively whether the histological effect was related to patient's prognosis. Furthermore, to evaluate the relationship between the effect of preoperative cisplatin treatment and p53 and cyclin D1 expression, we investigated p53 and cyclin D1 expression in pretreatment biopsy samples using an immunohistochemical analysis and compared the results with the histological effect to cisplatin in the resected oesophagus. The cases that showed immunohistochemical p53 staining in the pretreatment biopsy samples were resistant to cisplatin (P = 0.032). However, there was no relationship between cyclin D1 expression and histological effect (P = 0.230). Nevertheless, combined analysis of p53 and cyclin D1 can predict histological effect (P = 0.032). The prognosis of cisplatin-sensitive cases was significantly better than that of cisplatin-resistant cases (P = 0.041). Cox's multivariate analysis revealed that the histological effect was an independent prognostic factor. In contrast, p53 protein accumulation and cyclin D1 were not. Histological response after neoadjuvant cisplatin treatment is a prognostic factor for oesophageal SCC and cisplatin chemotherapy may be selected according to the findings of p53 and cyclin D1 expression.

Prognostic value of p27(Kip1) and CyclinD1 expression in esophageal cancer

It has recently been reported that the reduced expression of p27(Kip1) is a negative prognostic marker in several carcinomas. In this study, we examined the expression of p27(Kip1) in esophageal squamous cell carcinomas in order to understand its prognostic role. We also examined the expression of cyclinD1, which is believed to be correlated with the prognosis. Of the 128 cases, 64 cases (50.0%) showed low grade p27(Kip1) immunostaining and 64 cases (50.0%) high grade immunostaining; there was no significant difference in survival (p = 0.0915) between the two groups. On the other hand, 51 of the 156 cases (32.7%) were classified as the high cyclinD1 group, and 105 of the 156 cases (67.3%) as the low group, thus representing prognostic significance with regard to survival (p = 0.0161). Multivariate analysis indicated that gender, lymph node metastasis and positive cyclinD1 were independent prognostic factors. Our results revealed that cyclinD1 was a significant prognostic predictor of esophageal squamous cell carcinomas, whereas p27(Kip1) was not a significant prognostic factor.

Detection of colorectal carcinoma cells in circulating peripheral blood by reverse transcription-polymerase chain reaction targeting cytokeratin-20 mRNA

For the detection of circulating colorectal carcinoma cells, we investigated the presence of cytokeratin 20 (CK 20) mRNA in the peripheral blood of colorectal carcinoma patients. Application of our published technique resulted in analysis by reverse transcription followed by three-step nested polymerase chain reaction. This analysis could detect a single Colo 205 colon cancer cell mixed with 1 ml of blood. Our system also successfully detected the presence of CK 20 mRNA in actual patients' peripheral blood samples. Our highly sensitive and specific system for the detection of CK-20 mRNA from patients' peripheral blood thus seems to be useful for screening for circulating colorectal carcinoma cells.

Perforating lichen nitidus

A 32-year-old man with no particular family history nor past history visited our clinic in September 1992, with papules that he claimed had developed approximately 3 years earlier. No subjective symptoms accompanied then. On examination, numerous, discrete, pinhead-sized or half-ricecorn-sized, flesh-colored papules were observed on the dorsolateral side of his left hand and fingers. No central dimple or scaling were noticed clinically (Fig. 1). Laboratory tests revealed no abnormal findings. The histopathology of the biopsied specimen showed a circumscribed nest of infiltrating cells closely attached to the epidermis (Fig. 2). These infiltrating cells consisted of mononuclear lymphoid cells and histiocytes. The overlying epidermis was stretched and atrophic. A transepithelial perforation channel existed in direct contact with the surface. Amorphous debris containing cell nuclei lay within the channel (Fig. 2). Lymphoid cells were also observed above the keratin layer overlying the channel. At the lateral margin of the infiltrate, rete ridges extended downward in the manner of a claw clutching a ball. In a periodic-acid-Schiff (PAS)-stained section, a basement defect was observed around the channel.