Mammary tumor regression elicited by Wnt signaling inhibitor requires IGFBP5

Wnt ligand-driven tumor growth is inhibited by the soluble Wnt inhibitor Fzd8CRD, but the mechanism through which this effect is mediated is unknown. In the MMTV-Wnt1 mouse model, regression of mammary tumors by Fzd8CRD treatment coincides with an acute and strong induction of insulin-like growth factor (IGF)-binding protein IGFBP5, an antagonist of IGF signaling that mediates involution of mammary gland in females after offspring are weaned. In this study, we show that repression of this IGF inhibitory pathway is crucial for Wnt-driven growth of mammary tumors. We found that IGFBP5 regulation was mediated by the β-catenin-dependent Wnt pathway. Wnt, in addition to IGF ligands, facilitated tumor growth by paracrine communication among tumor cells. In addition, Fzd8CRD caused precocious induction of IGFBP5 in normal mammary glands undergoing involution, implying an acceleration of the involution process by inhibition of Wnt signaling. The molecular and phenotypic parallel between tumor regression and mammary gland involution suggests that Wnt-driven mammary tumors use the same growth mechanism as proliferating normal mammary glands.     

Carom: a novel membrane-associated guanylate kinase-interacting protein with two SH3 domains

MAGI-1 and CASK are membrane-associated guanylate kinases of epithelial junctions. MAGI-1 is localized at tight junctions in polarized epithelial cells, whereas CASK is localized along the lateral membranes. We obtained the KIAA0769 gene product through the yeast two-hybrid screening using MAGI-1 as a bait and named it Carom. Carom has a coiled-coil domain in the middle region, and two src homology 3 domains and a PSD-95/Dlg-A/ZO-1 (PDZ)-binding motif in the C-terminal region. Carom binds to the fifth PDZ domain of MAGI-1 and the calmodulin kinase domain of CASK in vitro. MAGI-1 and CASK bind to the distinct sequences in the C-terminal region of Carom, but still compete with each other for Carom binding. The study using a stable transformant of Madine Darby canine kidney (MDCK) cells expressing GFP-Carom revealed that Carom was partially overlapped by MAGI-1 in MDCK cells, which have not yet established mature cell junctions, but became separated from MAGI-1 and colocalized with CASK in polarized cells. Carom was highly resistant to Triton X-100 extractions and recruited CASK to the Triton X-100-insoluble structures. Carom is a binding partner of CASK, which interacts with CASK in polarized epithelial cells and may link it to the cytoskeleton.     

Differential gene expression screening between parental and highly metastatic pancreatic cancer variants using a DNA microarray

To clarify the difference in genes expressed in hematogenous metastasis and peritoneal dissemination, a broad analysis of differential gene expression analysis between parental cell lines and established metastatic sublines was performed. Using an oligonucleotide array (Gene Chip, Affymetrix), approximately 2,000 genes involved in cancer were analyzed for each of the cell lines. HPC-4H4 (highly metastatic lines to the liver) compared with HPC-4 (low metastatic parental lines), in which 20 overexpressed genes and 5 underexpressed genes were recognized. HPC-4P4a (highly metastatic to the peritoneum) compared with HPC-4, in which 12 overexpressed genes and 15 underexpressed genes were also recognized. Analysis of HPC-4H4 and HPC-4P4a showed comparative up-regulation of 20 genes and down-regulation of 13 in the former, HPC-4H4. Further studies are needed to validate our hypothesis that some of the resulting differentially expressed genes might be implicated in the development of metastasis in pancreatic cancer. In conclusion, this genome-wide expression analysis will help to clarify the molecular mechanisms of cancer metastasis and of the different levels of gene expression in a variety of metastatic potentials in pancreatic cancer.     

FDG-PET scanning after radiation can predict tumor regrowth three months later

PURPOSE: Positron emission tomography (PET) with 2-[(18)F]fluoro-2-deoxy-D-glucose (FDG) is well known for providing excellent clinical information regarding malignant tumors. We investigated whether dual-time FDG-PET performed immediately post radiation could predict early regrowth of malignant tumors. MATERIALS AND METHODS: Twenty patients with malignant tumors were included in this study. All patients received radiation, and each underwent FDG-PET before the initiation of therapy and within 10 days of completing their course of irradiation. PET images after irradiation were obtained at 60 min and 180 min post FDG injection. For 26 lesions in 20 patients, standardized uptake value (SUV) before and after treatment was calculated and then correlated with postradiation tumor response and outcome at 3 months status post irradiation. RESULTS: Retention index [RI = (SUV on delayed image - SUV on early image)/SUV on early image] after irradiation showed a significant difference between patients with residual tumor and those without residual tumor at 3 months status post irradiation (p < 0.0025). All 9 lesions in 6 patients with residual tumors showed more than 0.1 of RI, whereas none of the lesions with less than 0.1 of RI revealed residual tumors. CONCLUSIONS: Dual-time FDG-PET imaging just after irradiation is potentially useful for predicting early regrowth of malignant tumors.     

Prognostic value of overexpression of p53 in human ovarian carcinoma patients receiving cisplatin

A major obstacle to the treatment of ovarian carcinoma is intrinsic/acquired resistance to cisplatin-based chemotherapy. The clinical significance of p53 overexpression in patients with ovarian carcinoma is still controversial. The aim of this study was to investigate the independent prognostic significance of p53 overexpression in patients with ovarian carcinoma who are treated with cisplatin. We retrospectively examined the overexpression of p53 in primary ovarian carcinoma, and its association with chemotherapeutic efficacy. One hundred and thirty four ovarian carcinomas were surgically removed from patients who received adjuvant cisplatin-based chemotherapy. Immunohistochemical analysis of p53 was performed using a DO7 antibody against the p53 protein in 134 ovarian carcinomas. The significance of p53 in the prognosis of patients with ovarian carcinomas was also examined by a survival analysis of mortality follow-up data covering the period from 1988 to 2001. Thirty-three tumors (25%) exhibited p53 overexpression. Overexpression of p53 in grade 2/grade 3 tumors was significantly higher than that seen in grade 1 tumors (P=0.0088, 0.0229). Patients with tumors who also showed overexpression of p53 had a significantly inferior response to chemotherapy compared with the patients with p53-negative tumors (P=0.04). Cox regression analysis revealed that p53 overexpression was prognostic for poor disease outcome after adjustment for FIGO stage, grade and residual tumor. These findings suggest that overexpression of p53 in ovarian carcinoma is associated with unfavorable clinical outcome in patients treated with cisplatin-based chemotherapy. Therefore, detection of p53 overexpression using the DO7 antibody may be considered as a predictive marker of chemoresistance for cisplatin in patients with ovarian carcinoma.     

Optimal Interval for 18F-FDG-PET After Chemoradiotherapy for Rectal Cancer

Introduction

Although ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) has been increasingly used to evaluate the response to preoperative chemoradiotherapy (CRT) in patients with rectal cancer, the optimal intervals between completion of CRT, PET, and surgery have not been fully investigated.

Phase I/II Study of Preoperative Chemoradiotherapy With TEGAFIRI for Locally Advanced Rectal Cancer

Introduction

Chemoradiotherapy (CRT) is the standard treatment for locally advanced rectal cancer; however, the optimal chemotherapy sequence to administer simultaneously with radiotherapy remains unclear. We conducted a phase I/II study to test a new regimen, TEGAFIRI (combination tegafur, uracil [UFT], leucovorin [LV], irinotecan), for patients with locally advanced rectal cancer.

Characteristic findings of high-grade cervical intraepithelial neoplasia or more on magnifying endoscopy with narrow band imaging

Background

Colposcopy, which is a standard modality for diagnosing cervical intraepithelial neoplasia (CIN), can have limited accuracy owing to poor visibility. Flexible magnifying endoscopy with narrow band imaging (ME-NBI) has excellent diagnostic accuracy for early gastrointestinal neoplasms and is expected to be highly useful for CIN diagnosis. This study aimed to determine the characteristic findings and evaluate the diagnostic ability of ME-NBI for lesions ≥ CIN 3.

Methods

A well-designed prospective diagnostic case series conducted at multiple tertiary-care centers. A total of 24 patients who underwent cervical conization with a preoperative diagnosis of high-grade squamous cell intraepithelial lesions (HSILs) or lesions ≥ CIN 3 were enrolled. Prior to conization, still images and video of ME-NBI were captured to investigate the cervical lesions. The images were reviewed based on histological examination of the resected specimens.

Results

The NBI-ME images revealed the following abnormal findings: (1) light white epithelium (l-WE), (2) heavy white epithelium (h-WE), and (3) atypical intra-epithelial papillary capillary loop (IPCL). Pathological examination of the resected specimens confirmed cervical lesions ≥ CIN 3 in 21 patients. The ME-NBI findings were classified into four groups: l-WE, l-WE with atypical IPCL, h-WE, and h-WE with atypical IPCL, at rates of 0, 23.8, 9.5, and 66.7%, respectively. Additionally, all 3 patients with micro-invasive carcinoma showed a strong irregularity of IPCLs.

Conclusion

The lesions ≥ CIN 3 demonstrated characteristic ME-NBI findings of h-WE alone, or l-/h-WE with atypical micro-vessels. This study indicates that ME-NBI may have novel value for CIN diagnosis.