Organoid models of the tumor microenvironment and their applications.

A small percentage of data obtained from animal/2D culture models can be translated to humans. Therefore, there is a need to using native tumour microenvironment mimicking models to improve preclinical screening and reduce this attrition rate. For this purpose, currently, the utilization of organoids is expanding. Tumour organoids can recapitulate tumour microenvironment that is including cancer cells and non-neoplastic host components. Indeed, tumour organoids, both phenotypically and genetically, resemble the tumour tissue that originated from it. The unique properties of the tumour microenvironment can significantly affect drug response and cancer progression. In this review, we will discuss about various organoid culture strategies for modelling the tumour immune microenvironment, their applications and advantages in cancer research such as testing cancer immunotherapeutics, developing novel approaches for personalized medicine, testing drug toxicity, drug screening, study cancer initiation and progression, and we will also review the limitations of organoid culture systems.

Development of humanized mouse with patient-derived xenografts for cancer immunotherapy studies: A comprehensive review.

Immunotherapy has revolutionized cancer treatment, however, not all tumor types and patients are completely responsive to this approach. Establishing predictive pre-clinical models would allow for more accurate and practical immunotherapeutic drug development. Mouse models are extensively used as in vivo system for biomedical research. However, due to the significant differences between rodents and human, it is impossible to translate most of the findings from mouse models to human. Pharmacological development and advancing personalized medicine using patient-derived xenografts relies on producing mouse models in which murine cells and genes are substituted with their human equivalent. Humanized mice (HM) provide a suitable platform to evaluate xenograft growth in the context of a human immune system. In this review, we discussed recent advances in the generation and application of HM models. We also reviewed new insights into the basic mechanisms, pre-clinical evaluation of onco-immunotherapies, current limitations in the application of these models as well as available improvement strategies. Finally, we pointed out some issues for future studies.

The roles of tumor-associated macrophages in tumor angiogenesis and metastasis.

Tumor associated macrophages (TAMs) are the most frequent immune cells within tumor microenvironment (TME). There is growing evidence that TAMs are involved in tumor progression via multiple mechanisms. TAMs create an immunosuppressive TME by producing growth factors, chemokines, and cytokines which modulate recruitment of immune cells and inhibit anti-tumor responses. They also serve as angiogenesis promoting cells by production of pro-angiogenic factors and matrix metalloproteinases (MMPs) and vascular constructing which guarantee supplying oxygen and nutrients to solid tumor cells. Furthermore, TAMs play important functions in tumor metastasis through contributing to invasion, extravasation, survival, intravasation, and colonization of tumor cells. In this review, we summarized macrophage classification, TAMs polarization, and mechanisms underlying TAM-promoting angiogenesis and metastasis.

Pregnant woman with non-comatose autoimmune acute liver failure in the second trimester rescued using medical therapy: A case report.

We present the case of a 25-year-old woman at 16 weeks of gestation who presented with non-comatose autoimmune acute liver failure and was at high risk of developing fulminant hepatitis. Predictive formulas indicated a high probability of developing fulminant hepatitis. Unenhanced computed tomography showed marked hepatic atrophy and broadly heterogeneous hypoattenuating areas. The course of her illness was subacute, and the etiology of liver injury was unclear. Considering all of the above, we predicted a poor prognosis. Plasma exchange (PE) and continuous hemodiafiltration (CHDF) therapy were initiated just after admission. A few days after admission, a high titer (×80) of antinuclear antibody was noted. Because autoimmune hepatitis (AIH) was considered a cause of liver failure, treatment with moderate prednisolone (30 mg/day) doses was administrated, with careful consideration of her pregnancy. Thereafter, her laboratory findings and clinical course gradually improved without the need for liver transplantation. A liver biopsy at 18 days after admission indicated a diagnosis of AIH. She continued the pregnancy and delivered a healthy baby without any complications. Eventually, prednisolone doses were decreased to 10 mg, after which her liver function worsened. The second liver biopsy also indicated a diagnosis of AIH. Accordingly, low-dose prednisolone and azathioprine doses (50 mg/day) were administrated to recover her liver function, after which her liver function regained normalcy. This case illustrates that a pregnant woman with non-comatose autoimmune acute liver failure in the first or second trimester of pregnancy and her fetus can be rescued by PE/CHDF therapy and safe moderate doses of prednisolone.

In situ one step growth of amorphous tin oxide electron transport layer for high-performance perovskite solar cells.

Tin oxide used in electron transport layer (ETL) exhibits key role in transmitting electrons and blocking holes in perovskite solar cells (PSCs) device. However, crystal tin oxide nanoparticles (NPs) become necessary to form SnO2 film by method of spin-coating, resulting in possible surface defect and cracks among SnO2 NPs, corresponding to unsatisfied performance PSCs. Herein, an amorphous tin oxide thin film is creatively in situ grew onto Fluorine-doped Tin Oxide (FTO) substrate as ETL. The designed solar cell device with structure of FTO/SnO2/MAPbI3/Sprio-OMeTAD/Ag owns a champion photoelectric conversion efficiency (PCE) up to 17.64%, 76.20% of filling coefficient (FF), and 1.09 V of open-circuit voltage (Voc), in comparing with 16.43%, 64.35% and 1.05 V for control group (crystal tin oxide as ETL), respectively. Besides, the champion device keeps 83.33% of initial PCE under nitrogen (N2) condition for one month, in comparison with 76.09% for control group. This work provides a viable strategy for facile preparing amorphous tin oxide film based ETL in perovskite solar cells.

Acoustic radiation force impulse imaging for assessing graft fibrosis after pediatric living donor liver transplantation: a pilot study.

Graft fibrosis is a common finding during protocol biopsy examinations after pediatric liver transplantation. We evaluated the clinical utility of liver stiffness measurements by acoustic radiation force impulse (ARFI) imaging, a novel ultrasound-based elastography method, for assessing graft fibrosis after pediatric living donor liver transplantation (LDLT). We performed 73 liver stiffness measurements by ARFI imaging in 65 pediatric LDLT recipients through the upper midline of the abdomen (midline value) and the right intercostal space (intercostal value) around the time of protocol biopsy examinations. Fifty-nine of these liver stiffness measurements could be compared with histopathological findings. Graft fibrosis was assessed according to the degrees of portal and pericellular fibrosis. Significant fibrosis, which was defined as F2 or worse portal fibrosis and/or moderate or worse pericellular fibrosis, was observed in 14 examinations, which had significantly higher midline (P = 0.005) and intercostal values (P < 0.001) than the others. Liver stiffness measurements by ARFI imaging significantly increased with increases in the portal and pericellular fibrosis grades. For the diagnosis of significant fibrosis, the areas under the receiver operating characteristic curve (AUROCs) were 0.760 (P = 0.005) and 0.849 (P < 0.001) for the midline and intercostal values, respectively. The optimal cutoff values were 1.30 and 1.39 m/second for midline and intercostal values, respectively. Slight but significant elevations were noted in the results of biochemical liver tests: serum levels of γ-glutamyltransferase showed the highest AUROC (0.809, P = 0.001) with an optimal cutoff value of 20 IU/L. In conclusion, liver stiffness measurements by ARFI imaging had good accuracy for diagnosing graft fibrosis after pediatric LDLT. The pericellular pattern of fibrosis was frequently observed after pediatric LDLT, and moderate pericellular fibrosis was detectable by ARFI imaging.

Neutrophil elastase inhibitor improves survival rate after ischemia reperfusion injury caused by supravisceral aortic clamping in rats.

BACKGROUND: Sivelestat sodium hydrate is a specific neutrophil elastase inhibitor effective in acute lung injury (ALI) associated with systemic inflammatory response syndrome. Bowel ischemia reperfusion injury (IRI) induced by supravisceral aortic clamping is associated with an excessive systemic inflammatory response, resulting in remote organ damage, including ALI. In this study, we investigated whether sivelestat can attenuate neutrophil sequestration in the lung, alleviate ALI, and improve survival in a rat bowel IRI model. METHODS: Adult male Sprague-Dawley rats underwent bowel IRI induced by supravisceral aortic clamping and were randomly assigned to receive sivelestat or saline (control) and monitored for survival. We randomly assigned other rats to undergo laparotomy alone (sham operation), IRI alone, or IRI and sivelestat treatment. We evaluated blood samples for organ function, cytokine levels, and neutrophil elastase activity after reperfusion. Organs were analyzed histologically. We also determined lung injury in another set of rats. RESULTS: Bowel IRI induced a significant increase in serum variables indicative of organ function, cytokine concentrations, neutrophil elastase activity, and lung permeability and edema, which reflected the presence of both systemic inflammatory response syndrome and compensatory anti-inflammatory response syndrome. Treatment with sivelestat significantly improved survival rate, lung permeability and edema, and significantly decreased levels of creatinine, interleukin 6, interleukin 10, and neutrophil elastase activity. Histological studies showed that sivelestat-treated rats had less bowel IRI-induced damage to lung and liver tissue than controls. CONCLUSION: In a rat model, administration of sivelestat attenuated the effects of bowel IRI induced by supravisceral aortic clamping, and improved the survival rate.

Suppressive effects of interleukin-18 on liver function in rat liver allografts.

BACKGROUND: Interleukin-18 (IL-18) is a potent proinflammatory cytokine that augments both innate and acquired immune responses. It is also a crucial regulator of lymphocyte production of interferon-γ (IFN-γ), which can promote acute cellular rejection of transplanted solid organs. METHODS: To evaluate the role of IL-18 in liver transplantation, we constructed an adenoviral vector encoding IL-18 binding protein (Adex-IL18bp), which specifically suppressed the biologic activity of IL-18, and examined the effect of this suppression on liver allografts by using a high-responder rat model (ACI to Lewis) of orthotopic liver transplantation (OLTx). Donor rats were given one intravenous injection of Adex-IL18bp or Adex-LacZ (control vector) 2 d before OLTx. RESULTS: Seven days after OLTx, overexpression of IL-18bp resulting from the adenovirus gene transfer was associated with significantly decreased serum alanine aminotransferase levels and less histologic hepatic injury in recipient rats with Adex-IL18bp-pretreated donors compared with Adex-LacZ controls. Adex-IL18bp pretreatment also significantly prolonged rat/allograft survival, inhibited expression of IFN-γ, and reduced levels (versus control values) of both CXCL10 and CX3CL1, which can be induced by IFN-γ. CONCLUSION: These results suggest that IL-18 has an important role in liver allograft rejection through IFN-γ and chemokines and that specific suppression of IL-18 may improve liver function early after transplantation.

Carbohydrates based stimulus responsive nanocarriers for cancer-targeted chemotherapy: a review of current practices.

INTRODUCTION: Many nanocarriers have been developed to react physicochemically to exterior stimuli like ultrasonic, light, heat, and magnetic fields, along with various internal stimuli including pH, hypoxia, enzyme, and redox potential. Nanocarriers are capable to respond various stimuli within the cancer cells to enable on-demand drug delivery, activation of bioactive compounds, controlled drug release, and targeting ligands, as well as size, charge, and conformation conversion, enabling sensing and signaling, overcoming multidrug resistance, accurate diagnosis, and precision therapy. AREAS COVERED: Carbohydrates are ubiquitous biomolecules with a high proclivity for supramolecular network formation. Numerous carbohydrate-based nanomaterials have been used in biological solicitations and stimuli-based responses. Particular emphasis has been placed on the utilization of carbohydrate-based NPs and nanogels in various fields including imaging, drug administration, and tissue engineering. Because the assembly process is irreversible, carbohydrate-based systems are excellent ingredients for the development of stimulus-responsive nanocarriers for cancer-targeted chemotherapy. This review aims to summarise current research on carbohydrate-based nanomaterials, with an emphasis on stimuli-sensitive nanocarriers for cancer-targeted chemotherapy. EXPERT OPINION: Carbohydrates-based stimulus-responsive nanomaterials have been proved highly efficient for targeted delivery of anticancer drugs, thus leading to effective chemotherapy with minimum off-target effects.

Identification by differential tissue proteome analysis of talin-1 as a novel molecular marker of progression of hepatocellular carcinoma.

OBJECTIVE: Hepatocellular carcinoma (HCC) is characterized by a multistage process of tumor progression. This study addressed its molecular features to identify novel protein candidates involved in HCC progression. METHODS: Using liquid chromatography-tandem mass spectrometry, proteomes of 4 early HCCs and 4 non-HCC tissues derived from 2 cases of liver transplant surgery were compared with respect to the separation profiles of their tryptic peptides. Immunohistochemistry was performed on 106 HCC nodules to confirm the results of the proteomic analysis. RESULTS: Statistical analysis of the profiles selected the peptide peaks differentiating HCC from non-HCC. A database search of the tandem mass spectrometry data from those peptide peaks identified 61 proteins, including a cytoskeletal protein, talin-1, as upregulated in HCC. Talin-1 expression levels in HCC nodules were significantly associated with the dedifferentiation of HCC (p = 0.001). A follow-up survey of the examined clinical cases revealed a correlation between talin-1 upregulation and a shorter time to recurrence after resection (p = 0.039), which may be related to the higher rate of portal vein invasion in HCCs with talin-1 up-regulation (p = 0.029). CONCLUSIONS: Proteomic analysis led to identification of talin-1 as a promising HCC marker. Talin-1 upregulation is associated with HCC progression and may serve as a prognostic marker.

A male case of an undifferentiated carcinoma with osteoclast-like giant cells originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. A case report and review of the literature.

We report a rare male case of an undifferentiated carcinoma with osteoclast-like giant cells originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. A 59-year-old Japanese man with diabetes visited our hospital, complaining of fullness in the upper abdomen. A laboratory analysis revealed anemia (Hemoglobin; 9.7 g/dl) and elevated C-reactive protein (3.01 mg/dl). Carbohydrate antigen 19-9 was 274 U/ml and Carcinoembryonic antigen was 29.6 ng/ml. A computed tomography scan of the abdomen revealed a 14-cm cystic mass in the upper left quadrant of the abdomen that appeared to originate from the pancreatic tail. The patient underwent distal pancreatectomy/splenectomy/total gastrectomy/cholecystectomy. The mass consisted of a multilocular cystic lesion. Microscopically, the cyst was lined by cuboidal or columnar epithelium, including mucinous epithelium. Sarcomatous mononuclear cells and multinucleated osteoclast-like giant cells were found in the stroma. Ovarian-type stroma was not seen. We made a diagnosis of osteoclast-like giant cell tumor originating in an indeterminate mucin-producing cystic neoplasm of the pancreas. All surgical margins were negative, however, two peripancreatic lymph nodes were positive. The patient recovered uneventfully. Two months after the operation, multiple metastases occurred in the liver. He died 4 months after the operation.

Role of immune regulatory cells in breast cancer: Foe or friend?

Breast cancer (BC) is the most common cancer among women between the ages of 20 and 50, affecting more than 2.1 million people and causing the annual death of more than 627,000 women worldwide. Based on the available knowledge, the immune system and its components are involved in the pathogenesis of several malignancies, including BC. Cancer immunobiology suggests that immune cells can play a dual role and induce anti-tumor or immunosuppressive responses, depending on the tumor microenvironment (TME) signals. The most important effector immune cells with anti-tumor properties are natural killer (NK) cells, B, and T lymphocytes. On the other hand, immune and non-immune cells with regulatory/inhibitory phenotype, including regulatory T cells (Tregs), regulatory B cells (Bregs), tolerogenic dendritic cells (tDCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), myeloid-derived suppressor cells (MDSCs), mesenchymal stem cells (MSCs), and regulatory natural killer cells (NKregs), can promote the growth and development of tumor cells by inhibiting anti-tumor responses, inducing angiogenesis and metastasis, as well as the expression of inhibitory molecules and suppressor mediators of the immune system. However, due to the complexity of the interaction and the modification in the immune cells' phenotype and the networking of the immune responses, the exact mechanism of action of the immunosuppressive and regulatory cells is not yet fully understood. This review article reviews the immune responses involved in BC as well as the role of regulatory and inhibitory cells in the pathogenesis of the disease. Finally, therapeutic approaches based on inhibition of immunosuppressive responses derived from regulatory cells are discussed.

Oncolytic Virotherapy in Solid Tumors: The Challenges and Achievements.

Oncolytic virotherapy (OVT) is a promising approach in cancer immunotherapy. Oncolytic viruses (OVs) could be applied in cancer immunotherapy without in-depth knowledge of tumor antigens. The capability of genetic modification makes OVs exciting therapeutic tools with a high potential for manipulation. Improving efficacy, employing immunostimulatory elements, changing the immunosuppressive tumor microenvironment (TME) to inflammatory TME, optimizing their delivery system, and increasing the safety are the main areas of OVs manipulations. Recently, the reciprocal interaction of OVs and TME has become a hot topic for investigators to enhance the efficacy of OVT with less off-target adverse events. Current investigations suggest that the main application of OVT is to provoke the antitumor immune response in the TME, which synergize the effects of other immunotherapies such as immune-checkpoint blockers and adoptive cell therapy. In this review, we focused on the effects of OVs on the TME and antitumor immune responses. Furthermore, OVT challenges, including its moderate efficiency, safety concerns, and delivery strategies, along with recent achievements to overcome challenges, are thoroughly discussed.

Design and Development of Hybrid Hydrogels for Biomedical Applications: Recent Trends in Anticancer Drug Delivery and Tissue Engineering.

The applications of hydrogels in biomedical field has been since multiple decades. Discoveries in biology and chemistry render this platform endowed with much engineering potentials and growing continuously. Novel approaches in constructing these materials have led to the production of complex hybrid hydrogels systems that can incorporate both natural and synthetic polymers and other functional moieties for mediated cell response, tunable release kinetic profiles, thus they are used and research for diverse biomedical applications. Recent advancement in this field has established promising techniques for the development of biorelevant materials for construction of hybrid hydrogels with potential applications in the delivery of cancer therapeutics, drug discovery, and re-generative medicines. In this review, recent trends in advanced hybrid hydrogels systems incorporating nano/microstructures, their synthesis, and their potential applications in tissue engineering and anticancer drug delivery has been discussed. Examples of some new approaches including click reactions implementation, 3D printing, and photopatterning for the development of these materials has been briefly discussed. In addition, the application of biomolecules and motifs for desired outcomes, and tailoring of their transport and kinetic behavior for achieving desired outcomes in hybrid nanogels has also been reviewed.

Reduced transforming growth factor-beta receptor II expression in hepatocellular carcinoma correlates with intrahepatic metastasis.

Hepatocellular carcinoma (HCC) occurs mainly in the liver associated with chronic hepatitis and hepatic cirrhosis as a result of prolonged viral infection. Transforming growth factor-beta (TGF-beta) induces the fibrosis in hepatic cirrhosis, although it is also an inhibitor of hepatocyte proliferation. To understand the role of TGF-beta signaling in HCC progression, we analyzed gene expression in HCC cells in relation to TGF-beta signaling using a two-way clustering algorithm. By the analysis, five HCC cell lines were classified into two groups according to their metastatic capacity. TGF-beta receptor II (TGFBR2) was downregulated in metastatic cells, which did not show a response to TGF-beta. Immunohistochemistry demonstrated clear membrane distribution of TGFBR2 in noncancerous hepatocytes, whereas reduced TGFBR2 expression was observed in 34 of 136 HCCs. In clinical cases, reduced TGFBR2 expression correlated with larger tumor size (P<0.001), poor differentiation (P<0.001), portal vein invasion (P=0.002), intrahepatic metastasis (IM) (P<0.001), and shorter recurrence-free survival (P=0.022). In conclusion, reduced TGFBR2 expression was associated with aggressive features of HCC such as IM, and may represent an immunohistochemical biomarker to detect aggressive HCC.

Bmi-1 gene is upregulated in early-stage hepatocellular carcinoma and correlates with ATP-binding cassette transporter B1 expression.

Overexpression of "stemness gene"Bmi-1 has been identified in some solid tumors. We investigated Bmi-1 expression in hepatocellular carcinoma (HCC) and ATP-binding cassette transporter B1 (ABCB1) as a new potential target for Bmi-1. Bmi-1 was highly expressed in HCC cell lines and the most well differentiated cell line, KIM-1, showed the highest expression. Immunohistochemical, immunocytochemical, and immunoelectron microscopic analysis showed the Bmi-1 protein as having a high intensity of small dots within the nucleus which reflected concentrated sites of Bmi-1 repressive activity. Clear "dot-pattern" staining was observed in 24 of 37 (65%) well differentiated HCC (including 13 of 21 early nodules [62%]), in 32 of 71 (45%) moderately differentiated HCC, and 7 of 14 (50%) poorly differentiated HCC. A similar expression was not observed in non-cancerous background regions. High Bmi-1 expression was observed in the early and well differentiated HCC. Furthermore, overexpression and suppression of Bmi-1 was followed by a respective increase and decrease in ABCB1 expression. As with Bmi-1, high ABCB1 expression was also observed in the early and well differentiated HCC. A strong correlation between ABCB1 and Bmi-1 mRNA expression was seen in HCC cell lines and clinical samples (Pearson's correlation coefficient 0.95 and 0.90, respectively). The Bmi-1 gene is upregulated in HCC, and in particular is highly expressed in early and well differentiated HCC. The fact that this expression correlated with that of ABCB1 suggests a new regulation target for Bmi-1, and gives new insight into early hepatocarcinogenesis mechanisms and potential targets for future HCC treatment.

Adenylate cyclase-associated protein 1 overexpressed in pancreatic cancers is involved in cancer cell motility.

Pancreatic cancer has the worst prognosis among cancers due to the difficulty of early diagnosis and its aggressive behavior. To characterize the aggressiveness of pancreatic cancers on gene expression, pancreatic cancer xenografts transplanted into severe combined immunodeficient mice served as a panel for gene-expression profiling. As a result of profiling, the adenylate cyclase-associated protein 1 (CAP1) gene was shown to be overexpressed in all of the xenografts. The expression of CAP1 protein in all 73 cases of pancreatic cancer was recognized by immunohistochemical analyses. The ratio of CAP1-positive tumor cells in clinical specimens was correlated with the presence of lymph node metastasis and neural invasion, and also with the poor prognosis of patients. Immunocytochemical analyses in pancreatic cancer cells demonstrated that CAP1 colocalized to the leading edge of lamellipodia with actin. Knockdown of CAP1 by RNA interference resulted in the reduction of lamellipodium formation, motility, and invasion of pancreatic cancer cells. This is the first report demonstrating the overexpression of CAP1 in pancreatic cancers and suggesting the involvement of CAP1 in the aggressive behavior of pancreatic cancer cells.

Reconstitution of Schwannian stroma in neuroblastomas using human bone marrow stromal cells.

The Schwannian stroma in neuroblastomas is related to patient prognosis. There is debate surrounding the origin of Schwannian stroma in neuroblastomas: one theory is that the Schwann cells are derived from neoplastic cells, and the other is that they arise from normal cells surrounding the neuroblastoma. We examined whether human bone marrow stromal cells (hBMSCs) or human mesenchymal stem cells (hMSCs) could differentiate into Schwann cells in neuroblastomas. hBMSCs or hMSCs along with enhanced green fluorescent protein (EGFP) were injected into xenotransplanted neuroblastomas in nonobese diabetic mice with severe combined immunodeficiency and the resulting tumors were analyzed using immunohistochemistry. HBMSCs and hMSCs were co-cultured with neuroblastoma cells, and the induction of Schwann cell-specific molecules, S100beta and Egr-2, was monitored. S100beta-positive Schwannian stroma was observed only in neuroblastomas containing either hBMSCs or hMSCs, but not in neuroblastomas lacking these cells. Double staining with anti-S100 and anti-EGFP antibodies showed that S100-positive cells in neuroblastomas were also EGFP-positive. By contrast, hBMSCs did not develop into Schwann cells in Ewing's sarcoma, demonstrating that differentiation of transplanted hBMSCs or hMSCs into Schwann cells occurs specifically in neuroblastomas. Both S100beta and Egr-2 were expressed in hBMSCs or hMSCs co-cultured with neuroblastoma cells. HBMSCs or hMSCs may contribute to the formation of human tumor stroma. The Schwannian stroma of neuroblastomas appears to be derived from nonneoplastic stromal cells rather than neuroblastoma cells, further clarifying its developmental origins.

Localization of CD26/DPPIV in nucleus and its nuclear translocation enhanced by anti-CD26 monoclonal antibody with anti-tumor effect.

BACKGROUND: CD26 is a type II, cell surface glycoprotein known as dipeptidyl peptidase (DPP) IV. Previous studies have revealed CD26 expression in T cell leukemia/lymphoma and malignant mesothelioma, and an inhibitory effect of anti-CD26 monoclonal antibody (mAb) against the growth of CD26+ cancer cells in vitro and in vivo. The function of CD26 in tumor development is unknown and the machinery with which the CD26 mAb induces its anti-tumor effect remains uncharacterized. RESULTS: The localization of CD26 in the nucleus of T cell leukemia/lymphoma cells and mesothelioma cells was shown by biochemical and immuno-electron microscopic analysis. The DPPIV enzyme activity was revealed in the nuclear fraction of T cell leukemia/lymphoma cells. These expressions of intra-nuclear CD26 were augmented by treatment with the CD26 mAb, 1F7, with anti-tumor effect against the CD26+ T cell leukemia/lymphoma cells. In contrast, the CD26 mAb, 5F8, without anti-tumor effect, did not augment CD26 expressions in the nucleus. Biotin-labeled, cell surface CD26 translocated into the nucleus constantly, and this translocation was enhanced with 1F7 treatment but not with 5F8. CONCLUSION: These results indicate that the intra-nuclear CD26 which moves from plasma membrane may play certain roles in cell growth of human cancer cells.

Mutated D4-guanine diphosphate-dissociation inhibitor is found in human leukemic cells and promotes leukemic cell invasion.

OBJECTIVE: Rho GTPase may be involved in human cancer invasion via the augmentation of cell motility and adhesion. We report on two point mutations of the D4-guanine diphosphate (GDP)-dissociation inhibitor (GDI) gene, one of the Rho-GDIs, which were found in a human leukemic cell line, Reh, and the mutated D4-GDI functions as an accelerator of leukemic cell invasion. MATERIAL AND METHODS: We investigated the altered activity of GDP dissociation by mutated (mt) D4-GDI and the functions of this mt and wild-type (wt) D4-GDI in invasion. The mice inoculated with wt or mt D4-GDI vector-transfected Raji cells were observed and examined pathologically. Adhesiveness and cell motility of wt or mt D4-GDI vector-transfected Raji cells were examined. Finally, it was examined whether Rho activation was changed by mutation of D4-GDI under the condition of Rho-GDI knockdown. RESULTS: Two point mutations of the D4-GDI gene were found in Reh cells. The region of mutations is conserved among members of the Rho-GDI family at the amino acid level. D4-GDI with two mutations (V68L and V69A) functioned in a dominant negative manner in the inhibition of GDP dissociation from Rho. Severe combined immune-deficient mice inoculated with Raji cells developed hemiparalysis. The Raji cells were present in bone marrow and peripheral blood, and hepatic invasion was observed in 20% of the mice. Mice inoculated with wt D4-GDI vector-transfected Raji cells (wt D4) showed later paralysis and none developed hepatic invasion. Mice inoculated with mt D4-GDI-transfected Raji cells (mt D4) showed a 5-day reduction in the time to paraplegia and death. In addition, hepatic invasion was evident in 80% of mice transplanted with mt D4 cells. There were no differences in growth rates and amounts of guanine triphosphate (GTP)-bound Rho, cdc42, or Rac among all clones, however, GTP-bound Rho in mt D4 clone with short hairpin RNA (shRNA) vector for Rho-GDI knockdown was increased compared with wt D4 clone with shRNA vector for Rho-GDI knockdown. The mt D4 cells showed an augmentation of adhesiveness and cell motility. On the other hand, wt D4 cells showed a decreased ability of cell motility. CONCLUSION: These results suggest the mutated D4-GDI functions as a dominant negative molecule against the wt D4-GDI and accelerates invasion via regulation of cytoskeletal machinery.