Endoscopic ultrasound-guided inoculation of transmissible venereal tumor in the colon: A large animal model for colon neoplasia.

BACKGROUND: To develop and evaluate the feasibility of emerging interventions, animal models with accurate anatomical environment are required. OBJECTIVES: We aimed to establish a clinically relevant colorectal tumor model with canine transmissible venereal tumor (CTVT) utilizing endoscopic ultrasound (EUS) imaging guidance. DESIGN: Survival study using a canine model. SETTING: Endoscopic animal research laboratory at a tertiary cancer center. MATERIALS AND METHODS: This study involved five canines. INTERVENTIONS: A colorectal tumor model was established and evaluated in five canines under cyclosporine immune suppression. Under endoscopic imaging guidance, saline was injected into the submucosal layer forming a bleb. Subsequently, CTVT was inoculated into the bleb under EUS guidance. Endoscopy was the primary method of assessing tumor growth. Tumors developed in 60-130 days. Upon detection of lesions >1 cm, the animals were euthanized and the tumors were harvested for histopathological characterization. MAIN OUTCOME MEASUREMENTS: Success rate of tumor growth. The presence or absence of vasculature inside tumors. RESULTS: Colorectal tumor successfully developed in three out of the five animals (60%). Among the ones with tumor growth, average inoculated CTVT volume, incubation time, and tumor size was 1.8 cc, 65.7 days, and 2.0 cm, respectively. The two animals without tumor growth were observed for >100 days. In all the tumors, vascular structure was characterized with CD31 imunohistochemical stain. LIMITATIONS: Small number of animals. CONCLUSION: We succeeded in creating a new colorectal tumor canine model with CTVT utilizing EUS.

Requirement for ssbp2 in hematopoietic stem cell maintenance and stress response.

Transcriptional mechanisms governing hematopoietic stem cell (HSC) quiescence, self-renewal, and differentiation are not fully understood. Sequence-specific ssDNA-binding protein 2 (SSBP2) is a candidate acute myelogenous leukemia (AML) suppressor gene located at chromosome 5q14. SSBP2 binds the transcriptional adaptor protein Lim domain-binding protein 1 (LDB1) and enhances LDB1 stability to regulate gene expression. Notably, Ldb1 is essential for HSC specification during early development and maintenance in adults. We previously reported shortened lifespan and greater susceptibility to B cell lymphomas and carcinomas in Ssbp2(-/-) mice. However, whether Ssbp2 plays a regulatory role in normal HSC function and leukemogenesis is unknown. In this study, we provide several lines of evidence to demonstrate a requirement for Ssbp2 in the function and transcriptional program of hematopoietic stem and progenitor cells (HSPCs) in vivo. We found that hematopoietic tissues were hypoplastic in Ssbp2(-/-) mice, and the frequency of lymphoid-primed multipotent progenitor cells in bone marrow was reduced. Other significant features of these mice were delayed recovery from 5-fluorouracil treatment and diminished multilineage reconstitution in lethally irradiated bone marrow recipients. Dramatic reduction of Notch1 transcripts and increased expression of transcripts encoding the transcription factor E2a and its downstream target Cdkn1a also distinguished Ssbp2(-/-) HSPCs from wild-type HSPCs. Finally, a tendency toward coordinated expression of SSBP2 and the AML suppressor NOTCH1 in a subset of the Cancer Genome Atlas AML cases suggested a role for SSBP2 in AML pathogenesis. Collectively, our results uncovered a critical regulatory function for SSBP2 in HSPC gene expression and function.

Inactivation of CBF/NF-Y in postnatal liver causes hepatocellular degeneration, lipid deposition, and endoplasmic reticulum stress.

We previously demonstrated that CBF activity is needed for cell proliferation and early embryonic development. To examine the in vivo function of CBF in differentiated hepatocytes, we conditionally deleted CBF-B in hepatocytes after birth. Deletion of CBF-B resulted in progressive liver injury and severe hepatocellular degeneration 4 weeks after birth. Electron microscopic examination demonstrated pleiotropic changes of hepatocytes including enlarged cell and nuclear size, intracellular lipid deposition, disorganized endoplasmic reticulum, and mitochondrial abnormalities. Gene expression analyses showed that deletion of CBF-B activated expression of specific endoplasmic reticulum (ER) stress-regulated genes. Inactivation of CBF-B also inhibited expression of C/EBP alpha, an important transcription factor controlling various metabolic processes in adult hepatocytes. Altogether, our study reveals for the first time that CBF is a key transcription factor controlling ER function and metabolic processes in mature hepatocytes.

Magnetic resonance guided, focal laser induced interstitial thermal therapy in a canine prostate model.

PURPOSE: We evaluated a newly Food and Drug Administration cleared, closed loop, magnetic resonance guided laser induced interstitial thermal therapy system for targeted ablation of prostate tissue to assess the feasibility of targeting, real-time monitoring and predicting lesion generation in the magnetic resonance environment. MATERIALS AND METHODS: Seven mongrel dogs (University of Texas Health Science Center, Houston, Texas) with (2) and without (5) canine transmissible venereal tumors in the prostate were imaged with a 1.5 T magnetic resonance imaging scanner. Real-time 3-dimensional magnetic resonance imaging was used to accurately position water cooled, 980 nm laser applicators to predetermined targets in the canine prostate. Destruction of targeted tissue was guided by real-time magnetic resonance temperature imaging to precisely control thermal ablation. Magnetic resonance predictions of thermal damage were correlated with posttreatment imaging results and compared to histopathology findings. RESULTS: Template based targeting using magnetic resonance guidance allowed the laser applicator to be placed within a mean ± SD of 1.1 ± 0.7 mm of the target site. Mean width and length of the ablation zone on magnetic resonance imaging were 13.7 ± 1.3 and 19.0 ± 4.2 mm, respectively, using single and compound exposures. The damage predicted by magnetic resonance based thermal damage calculations correlated with the damage on posttreatment imaging with a slope near unity and excellent correlation (r(2) = 0.94). CONCLUSIONS: This laser induced interstitial thermal therapy system provided rapid, localized tissue heating under magnetic resonance temperature imaging control. Combined with real-time monitoring and template based planning, magnetic resonance guided, laser induced interstitial thermal therapy is an attractive modality for prostate cancer focal therapy.

Ability of herpes simplex virus vectors to boost immune responses to DNA vectors and to protect against challenge by simian immunodeficiency virus.

The immunogenicity and protective capacity of replication-defective herpes simplex virus (HSV) vector-based vaccines were examined in rhesus macaques. Three macaques were inoculated with recombinant HSV vectors expressing Gag, Env, and a Tat-Rev-Nef fusion protein of simian immunodeficiency virus (SIV). Three other macaques were primed with recombinant DNA vectors expressing Gag, Env, and a Pol-Tat-Nef-Vif fusion protein prior to boosting with the HSV vectors. Robust anti-Gag and anti-Env cellular responses were detected in all six macaques. Following intravenous challenge with wild-type, cloned SIV239, peak and 12-week plasma viremia levels were significantly lower in vaccinated compared to control macaques. Plasma SIV RNA in vaccinated macaques was inversely correlated with anti-Rev ELISPOT responses on the day of challenge (P value<0.05), anti-Tat ELISPOT responses at 2 weeks post challenge (P value <0.05) and peak neutralizing antibody titers pre-challenge (P value 0.06). These findings support continued study of recombinant herpesviruses as a vaccine approach for AIDS.

Limited contribution of humoral immunity to the clearance of measles viremia in rhesus monkeys.

The development of an improved vaccine for controlling measles virus (MV) infections in the developing world will require an understanding of the immune mechanisms responsible for the clearance of this virus. To evaluate the role of humoral immunity in the containment of MV, rhesus monkeys were treated at the time of MV challenge with either anti-CD20 monoclonal antibody (MAb) infusion, to deplete B lymphocytes, or both anti-CD20 and anti-CD8 MAb, to deplete both B lymphocytes and CD8+ effector T lymphocytes. Although the MV-specific antibody response in CD20+ lymphocyte-depleted monkeys was delayed by >1 week, the kinetics of MV clearance did not differ from those for monkeys that received control MAb. Furthermore, unusual clinical sequelae of MV infection were not observed in these monkeys. In contrast, MV-infected rhesus monkeys depleted of both CD20+ and CD8+ lymphocytes had a prolonged duration of viremia and developed a desquamating skin rash. These findings indicate that humoral immunity plays a limited role in the control of MV replication in an MV-naive individual and suggest that new measles vaccination strategies should focus on the elicitation of cell-mediated immune responses, in addition to neutralizing antibodies, to facilitate rapid elimination of locally replicating virus.

Role of CD8(+) lymphocytes in control and clearance of measles virus infection of rhesus monkeys.

The creation of an improved vaccine for global measles control will require an understanding of the immune mechanisms of measles virus containment. To assess the role of CD8(+) cytotoxic T lymphocytes in measles virus clearance, rhesus monkeys were depleted of CD8(+) lymphocytes by monoclonal anti-CD8 antibody infusion and challenged with wild-type measles virus. The CD8(+) lymphocyte-depleted animals exhibited a more extensive rash, higher viral loads at the peak of virus replication, and a longer duration of viremia than did the control antibody-treated animals. These findings indicate a central role for CD8(+) lymphocytes in the control of measles virus infections and the importance of eliciting a cell-mediated immune response in new measles vaccine strategies.