CHST4 Gene as a Potential Predictor of Clinical Outcome in Malignant Pleural Mesothelioma.

Malignant pleural mesothelioma (MPM) develops primarily from asbestos exposures and has a poor prognosis. In this study, The Cancer Genome Atlas was used to perform a comprehensive survival analysis, which identified the CHST4 gene as a potential predictor of favorable overall survival for patients with MPM. An enrichment analysis of favorable prognostic genes, including CHST4, showed immune-related ontological terms, whereas an analysis of unfavorable prognostic genes indicated cell-cycle-related terms. CHST4 mRNA expression in MPM was significantly correlated with Bindea immune-gene signatures. To validate the relationship between CHST4 expression and prognosis, we performed an immunohistochemical analysis of CHST4 protein expression in 23 surgical specimens from surgically treated patients with MPM who achieved macroscopic complete resection. The score calculated from the proportion and intensity staining was used to compare the intensity of CHST4 gene expression, which showed that CHST4 expression was stronger in patients with a better postoperative prognosis. The median overall postoperative survival was 107.8 months in the high-expression-score group and 38.0 months in the low-score group (p = 0.044, log-rank test). Survival after recurrence was also significantly improved by CHST4 expression. These results suggest that CHST4 is useful as a prognostic biomarker in MPM.

Gastric carcinosarcoma with FGFR2 amplification under long-term control with pazopanib: a case report and literature review.

BACKGROUND: Gastric carcinosarcoma is most frequently diagnosed at an advanced stage when the tumor is generally large with invasion into other organs, lymph node metastasis, and distant metastasis. Standard chemotherapy has not been established, and surgery is the only curative treatment. Here, we present a case of postoperative recurrence of gastric carcinosarcoma under long-term tumor control with pazopanib. CASE PRESENTATION: A 77-year-old man was referred to our hospital because of nausea and vomiting. Computed tomography and upper gastrointestinal endoscopy revealed a type 1 tumor arising from the gastric antrum and extending into the duodenal bulb. He underwent distal gastrectomy (D2) with Roux-en-Y reconstruction. Histopathologically, the tumor had mixed adenocarcinoma and sarcoma components. According to the tumor-node-metastasis classification, the diagnosis was primary gastric carcinosarcoma pT1bN1M0 stage IB. Liver metastasis was detected 2 months after surgery; multiple lung metastases were detected 17 month after surgery. A genomic profiling test was performed using liver specimens as the patient became refractory to chemotherapy commonly used for gastric cancer, and the test revealed FGFR2 amplification along with TP53 R209*, AKT3 N127D, NOTCH1 A2036T, and POLD1 M161I. The patient was treated with pazopanib (800 mg/daily), and the tumor growth was controlled for 11 months. CONCLUSIONS: We report a case of postoperative recurrence of gastric carcinosarcoma under long-term tumor control with pazopanib. This case suggested that pazopanib may be effective in treating gastric carcinosarcoma.

An adiponectin paralog protein, CTRP6 decreased the proliferation and invasion activity of oral squamous cell carcinoma cells: possible interaction with laminin receptor pathway.

C1q/tumor necrosis factor-related protein-6 (CTRP6), also known as CTRP6 is identified adiponectin paralog. Although recent studies have revealed that adiponectin has an inhibitory role in carcinogenesis, the role of CTRP6 in carcinogenesis remains unclear. In this study, we found that eukaryotic recombinant CTRP6 protein bound to the cell surface membrane of cultured oral squamous cell carcinoma cells by immunofluorescence staining. Screening of CTRP6 binding protein in expression library followed by co-immunoprecipitation assay revealed that CTRP6 bound to the precursor of laminin receptor. CTRP6 disturbed the binding of laminin to the laminin receptor. Interestingly, the eukaryotic recombinant CTRP6 protein significantly suppressed the proliferation and Matrigel invasion activity of oral squamous cell carcinoma SAS cells in a dose-dependent manner. Moreover, administration of CTRP6 significantly attenuated the growth of SAS cells in xenoplant mice model. Laminin and laminin receptor are known to be overexpressed and promote the tumor growth in OSCC. Combined together, the present findings suggest that CTRP6 could repress progression of oral squamous cell carcinoma cells, putatively through disrupting the laminin-laminin receptor axis.

TMEM207 hinders the tumour suppressor function of WWOX in oral squamous cell carcinoma.

The WW domain-containing oxidoreductase (WWOX) functions as a tumour suppressor in oral carcinogenesis. As aberrant TMEM207 expression may lead to tumour progression by hampering the tumour suppressor function of WWOX in various cancers, we explored the expression and pathobiological properties of TMEM207, focusing on the WWOX-mediated regulation of the HIF-1α pathway in oral squamous cell carcinoma (OSCC). TMEM207 immunoreactivity was detected in 40 of 90 OSCC samples but not in neighbouring non-tumorous epithelial tissues. Moreover, TMEM207 expression was significantly correlated with lymph node metastasis and poor prognosis. An in situ proximal ligation assay demonstrated the colocalization of TMEM207 and WWOX in invasive OSCC cells, especially glycogen-rich ones. Enforced expression of TMEM207 abrogated the binding of WWOX to HIF-1α, increased HIF-1α and GLUT-1 expression, even under normoxic conditions, and promoted tumour growth in a xenoplant assay using SAS tongue squamous cancer cells. In contrast, TMEM207 knockdown decreased GLUT-1 expression in two OSCC cell lines. As a whole, our findings indicate that the aberrant expression of TMEM207 contributes to tumour progression in OSCC, possibly via promoting aerobic glycolysis.

Novel Transgenic Mouse Model of Polycystic Kidney Disease.

Transmembrane protein 207 (TMEM207) is characterized as an important molecule for invasiveness of gastric signet-ring cell carcinoma cells. To clarify the pathobiological effects of TMEM207, we generated 13 transgenic mouse strains, designated C57BL/6-transgenic (Tg) (ITF-TMEM207), where the mouse Tmem207 is ectopically expressed under the proximal promoter of the murine intestinal trefoil factor gene. A C57BL/6-Tg (ITF-TMEM207) mouse strain unexpectedly exhibited a high incidence of spontaneous kidney cysts with histopathological features resembling human polycystic kidney disease, which were found in approximately all mice within 1 year. TMEM207 immunoreactivity was found in noncystic kidney tubules and in renal cysts of the transgenic mice. The ITF-TMEM207 construct was inserted into Mitf at chromosome 6. Cystic kidney was not observed in other C57BL/6-Tg (ITF-TMEM207) transgenic mouse strains. Although several genetically manipulated animal models exist, this mouse strain harboring a genetic mutation in Mitf and overexpression of Tmem207 protein was not reported as a model of polycystic kidney disease until now. This study demonstrates that the C57BL/6-Tg (ITF-TMEM207) mouse may be a suitable model for understanding human polycystic kidney disease.

R-THP-COP versus R-CHOP in patients younger than 70 years with untreated diffuse large B cell lymphoma: A randomized, open-label, noninferiority phase 3 trial.

Pirarubicin (tetrahydropyranyl adriamycin [THP]) is an anthracyclin with less cardiotoxicity than doxorubicin (DOX). We previously reported the efficacy and safety of R-THP-COP consisting of rituximab (R), THP, cyclophosphamide (CPA), vincristine (VCR), and prednisolone (PSL) for diffuse large B cell lymphoma (DLBCL) in phase 2 studies. Here, we prospectively compared the efficacy and safety of the R-THP-COP and standard R-CHOP regimen (consisting of R, CPA, DOX, VCR, and PSL) in a noninferiority phase 3 trial. This prospective, randomized phase 3 study included patients younger than 70 years of age with previously untreated DLBCL. The regimen consisted of R (day 1), DOX, or THP (day 3), CPA (day 3), VCR (day 3), and PSL for 5 days every 3 weeks for 6 to 8 cycles. Between July 5, 2006 and June 11, 2013, 81 patients were randomly assigned to the treatment groups (R-CHOP group, 40 patients; R-THP-COP group, 41 patients). R-THP-COP was noninferior to R-CHOP, as assessed by the primary endpoint of complete response rate (85% vs 85% respectively). With a median follow-up of 75.2 months, the 5-year overall survival was 87% in the R-CHOP group and 82% in the R-THP-COP group (hazard ratio [HR]: 0.89, 95% confidence interval [CI]: 0.31-2.49; P = .82). The 5-year progression-free survival was 74% in the R-CHOP group and 79% in the R-THP-COP group (HR: 1.37, 95% CI: 0.56-3.55; P = .49). No grade 3 cardiac side effects were observed in either group. No serious late adverse reactions were observed in either group, with the exception of therapy-related acute myeloid leukemia in the R-THP-COP group. These data indicate that R-THP-COP is noninferior to R-CHOP with regard to clinical response, and has an acceptable safety profile. Thus, this regimen may be an alternative therapy to R-CHOP.

CHOP or THP-COP regimens in the treatment of newly diagnosed peripheral T-cell lymphoma, not otherwise specified: a comparison of doxorubicin and pirarubicin.

The CHOP regimen consisting of cyclophosphamide, doxorubicin (DOX), vincristine and prednisolone has been the most used regimen for peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS). Pirarubicin [tetrahydropyranyladriamycin (THP)], a derivative of DOX, is an anthracycline with reportedly less cardiotoxicity than DOX. Here, we confirmed the efficacy of THP-COP using THP instead of DOX in the treatment of PTCL-NOS. The study protocol employed a retrospective, consecutive entry design. We retrospectively analysed 56 patients with PTCL-NOS who had received THP-COP or CHOP. These regimens were performed every 21 days. Twenty-nine patients received THP-COP, and 27 received CHOP. There were no significant differences in known prognostic factors, including in the International Prognostic Index (IPI) and the prognostic index for T-cell lymphoma (PIT), between the two groups. Complete remission rates in patients with THP-COP and CHOP were 52% in both groups; the 3-year overall survival (OS) rates were 67% and 52% (p = 0.074), and the 3-year progression-free survival (PFS) rates were 51% and 29% (p = 0.070), respectively. In patients with low IPI (low or low-intermediate), THP-COP had significantly better 3-year OS (100% vs. 64%; p < 0.001) and 3-year PFS (75% vs. 33%; p < 0.05) than CHOP. Similar differences between THP-COP and CHOP were observed in patients with a low PIT (groups 1 or 2). Our study showed that THP-COP produced results equivalent to CHOP regarding efficacy and safety in patients with PTCL-NOS. In patients with low IPI or PIT, THP-COP resulted in significantly better prognosis. Copyright © 2015 John Wiley & Sons, Ltd.

A salvage chemotherapy of R-P-IMVP16/CBDCA consisting of rituximab, methylprednisolone, ifosfamide, methotrexate, etoposide, and carboplatin for patients with diffuse large B cell lymphoma who had previously received R-CHOP therapy as first-line chemotherapy.

We have reported the efficacy of the salvage chemotherapy P-IMVP16/CBDCA for patients with diffuse large B cell lymphoma (DLBCL) who had previously received CHOP before the availability of rituximab (R). Here, we confirmed the efficacy of R combined with P-IMVP16/CBDCA as a salvage chemotherapy for patients with DLBCL, who had previously received R-CHOP. We retrospectively analysed 59 patients with relapse or refractory DLBCL (38 male patients and 21 female patients) presenting between June 2004 and June 2013. The patients received R 375 mg/m2 on day 1, methylprednisolone 1000 mg/body for 3 days (from day 3 to day 5), ifosfamide 1000 mg/m2 for 5 days (from day 3 to day 7), methotrexate 30 mg/m2 on day 5 and day 12, etoposide 80 mg/m2 for 3 days (from day 3 to day 5), and carboplatin 300 mg/m2 on day 3 every 21 days. Patients aged 70 years or older were given 75% of the standard dose. The overall response rate (complete response + partial response) was 64.4%. The 2-year overall survival rate was 55.3%. The 2-year progression free survival rate was 34.7%. The 2-year overall survival rate was 61.5% for the relapse patients, and 15.6% for the refractory patients (p < 0.0001). One patient died because of sepsis related to the treatment regimen. Non-hematological adverse effects were mild and tolerable. The R-P-IMVP-16/CBDCA regimen displayed a significant activity in relapsed DLBCL, with acceptable toxicity, and should be considered a candidate for salvage chemotherapy. Copyright © 2016 John Wiley & Sons, Ltd.

Serum concentrations of l-kynurenine predict clinical outcomes of patients with peripheral T-cell lymphoma, not otherwise specified.

Indoleamine 2,3-dioxygenase exerts intense immunomodulatory effects due to enzymatic activities that catalyze the breakdown of the essential amino acid l-tryptophan. The activity of indoleamine 2,3-dioxygenase can be estimated by measuring serum l-kynurenine concentrations. Here, we aimed to determine the role of l-kynurenine as a prognostic factor for peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) in a retrospective analysis of data derived from 31 consecutive patients between June 2000 and March 2013 who were histologically diagnosed with PTCL-NOS according to the World Health Organization classification and treated with 6-8 cycles of cyclophosphamide, doxorubicin or pirarubicin, vincristine, and prednisolone. l-kynurenine concentrations in serum samples collected at admission were measured using high-performance liquid chromatography. The median serum concentration of l-kynurenine was 3.28 (range 0.92-8.16) µM. The l-kynurenine cutoff was set at 3.07 µM using receiver operating characteristics curves. The complete remission rates of patients with l-kynurenine <3.07 and ≥3.07 µM were 69% and 51%, respectively. The 5-year overall survival (OS) rates for patients with l-kynurenine <3.07 and ≥3.07 µM were 80.2% and 23.4%, respectively (p < 0.001). More advanced age, poor performance status, elevated lactate dehydrogenase, an unfavorable International Prognostic Index, and a poor prognostic index for T-cell lymphoma were significantly worse factors for OS. Multivariate analyses revealed only l-kynurenine as an independent prognostic factor for OS. In conclusion, serum concentrations of l-kynurenine might comprise a novel prognostic factor with which to determine the outcomes of treatment for PTCL-NOS. Copyright © 2016 John Wiley & Sons, Ltd.

Adiponectin and Intelectin-1: Important Adipokine Players in Obesity-Related Colorectal Carcinogenesis.

Overweight is believed to be associated with colorectal cancer risk. Adipose tissue is loose connective tissue composed of adipocytes. It is now recognized as a major endocrine organ, secreting humoral factors collectively called adipokines. Aberrant hormonal systems consisting of modulated adipokines and their receptors are thought to play a role in colorectal carcinogenesis and cancer progression in obese conditions. However, it is still unclear whether and how each adipokine relates to colorectal carcinogenesis. Notably, a couple of molecules that were initially proposed to be obesity-related adipokines were disqualified by subsequent studies. The adipokines, adiponectin, and intelectin-1 (also known as omentin-1), whose levels are decreased in obesity, act as tumor suppressor factors in various cancers. Numerous studies have demonstrated a link between the insufficient expression and function of adiponectin and its receptor, T-cadherin, in colorectal carcinogenesis. Moreover, our recent study indicated that loss of TMEM207, which is critical for the proper processing of intelectin-1 in the colon mucosa, leads to insufficient intelectin-1 production, thus participating in colorectal carcinogenesis. Here, we discuss the recent understanding of the role of adipokines in colorectal carcinogenesis and subsequently describe the potent tumor suppressor roles of intelectin-1 and TMEM207 in colorectal cancer.

Sarcopenia is an independent prognostic factor in male patients with diffuse large B-cell lymphoma.

Sarcopenia reportedly predicts poor outcomes in elderly patients with diffuse large B-cell lymphoma (DLBCL). However, because previous studies only involved elderly patients, it is difficult to generalize these results to all patients with DLBCL. We retrospectively analyzed 207 patients with DLBCL who received the R-CHOP or R-THP-COP regimen between June 2004 and May 2014. Sarcopenia was measured by the analysis of CT images at the L3 level before treatment. The surface of muscular tissues was selected according to the CT Hounsfield unit. This value was normalized for stature in order to calculate the L3 skeletal muscle index (L3 SMI, cm(2)/m(2)). Median age at diagnosis in the 121 males and 86 females was 67 years (range, 19-86 years). The sex-specific cutoffs for the L3 SMI were determined by receiver operator curve (ROC) analysis. Sarcopenic patients were older than non-sarcopenic patients, with a median age of 70 and 65 years, respectively (p < 0.001). Other International Prognostic Index factors were not significantly different when comparing sarcopenic and non-sarcopenic patients. With a median follow-up of 50.4 months, the 3-year overall survival (OS) was 70 % in the sarcopenic group and 85 % in the non-sarcopenic group (p = 0.0260). In a subgroup analysis by gender, there was a significant difference in the OS when comparing sarcopenic and non-sarcopenic patients in males but not in females (p = 0.0003, p = 0.4440, respectively). Sarcopenia is an independent prognostic factor in male patients with DLBCL.

Pathobiological properties of the ubiquitin ligase Nedd4L in melanoma.

A recent global gene expression profiling study unexpectedly showed that activated oncogenic NRAS may recruit neural precursor cell expressed, developmentally downregulated 4L (Nedd4L; a human homologue of Nedd4-2) in cultured melanoma cells. However, whether Nedd4L was expressed in melanoma tissues or participated in melanoma carcinogenesis remains to be clarified. Here, we investigated the expression status of Nedd4L in human melanocytes, benign nevi and melanoma tissue specimens and subsequently attempted to determine the role of Nedd4L in melanoma cell growth. Immunohistochemical staining revealed that Nedd4L was not present in any non-tumorous melanocytes or in 18 benign nevi tissues, but it was detected in 34 of 79 cutaneous melanomas and 9 of 32 nodal metastatic melanomas. Downregulation of Nedd4L significantly reduced the growth of cultured G361 melanoma cells in vitro. Moreover, exogenous Nedd4L expression significantly promoted the growth of A2058 melanoma cells in vivo in a xenograft assay. The present findings indicate that Nedd4L expression may be increased to facilitate tumour growth in many melanomas.

Mantle cell lymphoma with a unique pattern of CD5 expression: a case report with review of the literatures.

Mantle cell lymphoma (MCL) is a unique subtype of B-cell non-Hodgkin's lymphoma characterized by chromosomal translocation t(11;14)(q13;q32), positive CD5, and nuclear cyclin D1 overexpression with unfavorable prognosis. We report herein a case of MCL in a 73-year-old male diagnosed with diffuse large B-cell lymphoma (ileal tumor) at another hospital, who subsequently relapsed with CD5-negative MCL. At the 1st relapse, he developed neck lymph node swelling, of which biopsy showed proliferation of atypical large pleomorphic cells with CD5-negativity by both immunohistochemistry and flow cytometry. At the 2nd relapse, he again developed an ileal tumor, of which biopsy showed positivity for CD5, CD20, and cyclin D1. In MCL, CD5-negative expression has sometimes been reported as having pleomorphic and blastoid variants. The present case was also histologically the pleomorphic type, but the CD5 expression changed from negative at the onset and the 1st relapse to positive at the 2nd relapse. This is a rare and interesting case because of the different expression of CD5 at all stage. This phenomenon made the diagnosis of MCL difficult.

Inducing Melanoma Cell Apoptosis by ERp57/PDIA3 Antibody in the Presence of CPI-613 and Hydroxychloroquine.

The combination of the cancer mitochondrial metabolic inhibitor CPI-613 and hydroxychloroquine has tumor-suppressive effects on clear cell sarcoma, which shares pathobiological properties with melanoma. Therefore, we intended to examine the effects of a combination of CPI-613 and hydroxychloroquine on the growth of melanoma cells in the present study. However, cell death was not induced in melanoma cells. Therefore, a monoclonal antibody, ICT, that induced apoptosis in melanoma cells in combination with CPI-613 and hydroxychloroquine was developed. Immunoprecipitation, mass spectrometry, and small interfering RNA (siRNA)-mediated gene silencing demonstrated that ICT targeted Endoplasmic Reticulum Resident Protein 57/ Protein Disulfide Isomerase Family A Member 3 (ERp57/PDIA3), which was first identified as being upregulated by metabolic depletion stress and is localized on the cell surface during immunogenic cell death. The combination of CPI-613 and hydroxychloroquine enhanced the localization of ERp57/PDIA3 to the surface of melanoma cells. siRNA-mediated downregulation of ERp57/PDIA3 did not significantly induce ICT-mediated apoptosis in melanoma cells in the presence of CPI-613 and hydroxychloroquine. Therefore, the ICT antibody acts as a tumor suppressor in melanoma cells by targeting the cell membrane ERp57/PDIA3, expression of which was enhanced by the combination of CPI-613 and hydroxychloroquine.

Expression of IZUMO2 in colorectal cancer in association with clinicopathological features.

IZUMO2 belongs to the testis-expressed IZUMO family of proteins, which are characterized by an N-terminal IZUMO domain. Based on integrated analysis of expression profiles and matched DNA methylation data from a public database, IZUMO2 represents a prognosis-related methylation-driven gene in colorectal cancer. However, it remains unclear whether IZUMO2 protein expression is suppressed or overexpressed in colorectal cancer cells. In this study, we aimed to elucidate the expression of the IZUMO2 protein in colorectal cancer, with a focus on the clinicopathological features. Sixty-four colorectal cancer tissue specimens were immunohistochemically stained using specific antibodies against IZUMO2. IZUMO2 immunoreactivity was detected at the invasion front in 30 of the 64 colorectal cancer samples. Kaplan-Meier analysis demonstrated that patients with IZUMO2 immunoreactivity had a relatively shorter overall and progression-free survival (log-rank test, P = 0.046 and 0.019, respectively). IZUMO2 immunoreactivity served as an independent factor predictive of poor progression-free survival in colorectal cancer (P = 0.025) as determined via the Cox proportional hazard regression model. Moreover, IZUMO2 immunoreactivity represented an independent factor for poor overall survival (P = 0.035) and progression-free survival (P = 0.013) in patients with colon cancer. The present findings suggest that IZUMO2 is expressed in many colorectal cancers, especially at the cancer invasion front, and may represent an indicator of poor prognosis in colorectal cancer.

Implication of IZUMO2 in the cell-in-cell phenomenon: A potential therapeutic target for triple-negative breast cancer.

BACKGROUND: Triple-negative breast cancer (TNBC) is characterized by the loss of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The aggressive clinicopathological features and resistance to currently available therapeutics of the disease warrant an urgent need for the development of novel alternate therapeutic options. We have previously reported adiponectin-expressing regulatory T cells (A-Tregs), which can induce apoptosis in TNBC through the cell-in-cell phenomenon. In this study, we aimed to elucidate the molecule that allows TNBC cells to engulf A-Tregs. METHODS: A monoclonal antibody, which repressed the engulfment of A-Tregs by TNBC cells, was developed. Immunoprecipitation followed by mass spectrometry and small interfering RNAs-mediated gene silencing was performed to characterize the antigen. RESULTS: We successfully generated a monoclonal antibody, designated G1D7, which abrogated the engulfment of A-Tregs by TNBC and subsequent A-Treg-mediated apoptosis. G1D7 detected the immunoglobulin-like type I membrane protein IZUMO2, a molecule related to IZUMO1 that is essential for cell-cell membrane binding and fusion of sperm to oocyte. CONCLUSION: The findings highlight the importance of IZUMO2 on TNBC cells in facilitating the cell-in-cell phenomenon by A-Tregs.

Discrepancy in the Location of Prostate Cancer Indicated on Biparametric Magnetic Resonance Imaging and Pathologically Diagnosed Using Surgical Specimens.

Accurate diagnosis of the localization of prostate cancer (PCa) on magnetic resonance imaging (MRI) remains a challenge. We aimed to assess discrepancy between the location of PCa pathologically diagnosed using surgical specimens and lesions indicated as possible PCa by the Prostate Imaging Reporting and Data System on MRI. The primary endpoint was the concordance rate between the site of probable clinically significant PCa (csPCa) identified using biparametric MRI (bpMRI) and location of PCa in the surgical specimen obtained using robot-assisted total prostatectomy. Among 85 lesions identified in 30 patients; 42 (49.4%) were identified as possible PCa on MRI. The 85 PCa lesions were divided into positive and negative groups based on the bpMRI results. None of the patients had missed csPCa. Although the diagnostic accuracy of bpMRI was relatively high for PCas located in the middle of the prostate (p = 0.029), it was relatively low for PCa located at the base of the prostate, all of which were csPCas. Although current modalities can accurately diagnose PCa, the possibility that PCa is present with multiple lesions in the prostate should be considered, even if MRI does not detect PCa.

Imatinib mesylate inhibits cell growth of malignant peripheral nerve sheath tumors in vitro and in vivo through suppression of PDGFR-ß.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive and associated with poor prognosis. Basic research to develop new treatment regimens is critically needed. METHODS: The effects of imatinib mesylate on MPNSTs were examined in six human MPNST cell lines and in a xenograft mouse model. RESULTS: The results showed expression of platelet-derived growth factor receptor-ß and suppression of its phosphorylation by imatinib mesylate in all six cell lines. Imatinib mesylate effectively suppressed MPNST cell growth in vitro at concentrations similar to those used clinically (1.46 - 4.6 µM) in three of six cell lines. Knockdown of PDGFR-ß by transfection with a specific siRNA also caused significant reduction in cell proliferation in the sensitive cell lines, but not in the resistant cell lines. Furthermore, imatinib mesylate also significantly suppressed colony formation within soft agar and tumor growth in xenograft models using two of the three sensitive MPNST cell lines. There was excellent agreement between in vitro and in vivo sensitivity to imatinib mesylate, suggesting possible selection of imatinib-sensitive tumors by in vitro analysis. CONCLUSIONS: The results suggest that imatinib mesylate may be useful in the treatment of MPNST patients and in vitro studies may help select cells that are sensitive to imatinib mesylate in vivo.

Experimental model of micronodular thymic neoplasm with lymphoid stroma.

BACKGROUND: Micronodular thymic neoplasm with lymphoid stroma (MNT), a subtype of thymic tumor, is histopathologically characterized by micronodular thymic epithelial cell nests with lymphoid stroma. Despite the distinct histopathology of MNT, its pathogenesis remains unclear. METHODS: In this study, we aimed to examine a thymic tumor harboring thymic epithelial and lymphoid cells in a nonobese diabetic/severe combined immunodeficiency mouse. RESULTS: The excised tumor cells were cultured in vitro and comprised epithelial tumor cells and lymphoid cells. During a three-dimensional cell culture, the epithelial tumor cells formed micronodular cell nests surrounded by lymphoid stroma. Notably, the lymphoid cells underwent apoptosis when they were separated from the epithelial tumor cells. Cutaneous transplantation of the cultured epithelial cells with splenocytes from BALB/c mice led to tumor formation, and these cells demonstrated a histopathology similar to that of human MNT in a nonobese diabetic/severe combined immunodeficiency mouse. CONCLUSION: Given its overlapping features with human MNT, the transplanted tumor could serve as an experimental model of this disease.

Adiponectin-expressing Treg-containing T cell fraction inhibits tumor growth in orthotopically implanted triple-negative breast cancer.

BACKGROUND: In our previous study, we identified a population of adiponectin expressing regulatory T cells (Tregs) residing within thymic nurse cell complexes, which were capable of inhibiting the development of breast cancer in vitro. Triple-negative breast cancer (TNBC) with no proper treatment at present is characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2. In this study, we aimed to investigate the potential of a cultured T cell fraction comprising adiponectin-expressing Tregs, referred to as A-TregTF (adiponectin-expressing Treg-containing T cell fraction), in inhibiting the progression of TNBC in vivo. METHODS: The efficacy of a spontaneously expanding T cell fraction comprising adiponectin-expressing Treg in inhibiting tumor growth was analyzed in a murine orthotopic 4 T1-Luc TNBC model. RESULTS: The treatment with T cell fraction containing adiponectin-expressing Tregs significantly inhibited the growth and metastasis of orthotopically transplanted 4 T1-Luc tumor cells. Histopathological examination further revealed that the adiponectin-expressing Tregs infiltrated the tumor tissue via a cell-in-cell mechanism and were found to be specifically localized around the necrotic areas. CONCLUSIONS: Based on our findings, the T cell fraction comprising adiponectin-expressing Tregs, represents a potential candidate for adoptive cell therapy against TNBC.