Therapeutic effects of TM4SF5-targeting chimeric and humanized monoclonal antibodies in hepatocellular and colon cancer models

The transmembrane 4 L six family member 5 (TM4SF5) is aberrantly expressed in hepatocellular and colorectal cancers, and has been implicated in tumor progression, suggesting that it could serve as a novel therapeutic target. Previously, we screened a murine antibody phage-display library to generate a novel monoclonal antibody, Ab27, that is specific to the extracellular loop 2 of TM4SF5. In this study, we evaluated the effects of chimeric Ab27 using cancer cells expressing endogenous TM4SF5 or stably overexpressing TM4SF5 in vivo and in vitro. Monotherapy with Ab27 significantly decreased tumor growth in liver and colon cancer xenograft models, including a sorafenib-resistant model, and decreased the phosphorylation of focal adhesion kinase (FAK), p27^Kip1, and signal transducer and activator of transcription 3 (STAT3). No general Ab27 toxicity was observed in vivo. Combination treatment with Ab27 and sorafenib or doxorubicin exerted higher antitumor activity than monotherapy. In addition, we humanized the Ab27 sequence by the complementarity-determining region (CDR) grafting method. The humanized antibody Ab27-hz9 had reduced immunogenicity but exhibited target recognition and antitumor activity comparable with those of Ab27. Both Ab27 and Ab27-hz9 efficiently targeted tumor cells expressing TM4SF5 in vivo. These observations strongly support the further development of Ab27-hz9 as a novel therapeutic agent against liver and colorectal cancers.

TMPRSS4 promotes cancer stem-like properties in prostate cancer cells through upregulation of SOX2 by SLUG and TWIST1

Background

Transmembrane serine protease 4 (TMPRSS4) is a cell surface–anchored serine protease. Elevated expression of TMPRSS4 correlates with poor prognosis in colorectal cancer, gastric cancer, prostate cancer, non–small cell lung cancer, and other cancers. Previously, we demonstrated that TMPRSS4 promotes invasion and proliferation of prostate cancer cells. Here, we investigated whether TMPRSS4 confers cancer stem–like properties to prostate cancer cells and characterized the underlying mechanisms.

Methods

Acquisition of cancer stem–like properties by TMPRSS4 was examined by monitoring anchorage-independent growth, tumorsphere formation, aldehyde dehydrogenase (ALDH) activation, and resistance to anoikis and drugs in vitro and in an early metastasis model in vivo. The underlying molecular mechanisms were evaluated, focusing on stemness-related factors regulated by epithelial–mesenchymal transition (EMT)-inducing transcription factors. Clinical expression and significance of TMPRSS4 and stemness-associated factors were explored by analyzing datasets from The Cancer Genome Atlas (TCGA).

Results

TMPRSS4 promoted anchorage-independent growth, ALDH activation, tumorsphere formation, and therapeutic resistance of prostate cancer cells. In addition, TMPRSS4 promoted resistance to anoikis, thereby increasing survival of circulating tumor cells and promoting early metastasis. These features were accompanied by upregulation of stemness-related factors such as SOX2, BMI1, and CD133. SLUG and TWIST1, master EMT-inducing transcription factors, made essential contributions to TMPRSS4-mediated cancer stem cell (CSC) features through upregulation of SOX2. SLUG stabilized SOX2 via preventing proteasomal degradation through its interaction with SOX2, while TWIST1 upregulated transcription of SOX2 by interacting with the proximal E-box element in the SOX2 promoter. Clinical data showed that TMPRSS4 expression correlated with the levels of SOX2, PROM1, SNAI2, and TWIST1. Expression of SOX2 was positively correlated with that of TWIST1, but not with other EMT-inducing transcription factors, in various cancer cell lines.

Conclusions

Together, these findings suggest that TMPRSS4 promotes CSC features in prostate cancer through upregulation of the SLUG- and TWIST1-induced stem cell factor SOX2 beyond EMT. Thus, TMPRSS4/SLUG–TWIST1/SOX2 axis may represent a novel mechanism involved in the control of tumor progression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02147-7.

The association of stroke rate with low density lipoprotein and statin exposure in patients with atrial fibrillation (AF)

Background

There are limited data on the association between cholesterol levels and stroke risk in atrial fibrillation (AF).

Objective

To quantify the association of stroke rate in AF with low-density lipoprotein (LDL) levels and statin use.

Methods

Using linked administrative databases in Ontario, Canada, we conducted a population-based retrospective cohort study of patients aged ≥66 years, diagnosed with AF between 2009–2019. We used cause-specific hazard regression to determine the association of statin use with stroke rate. We developed a second cause-specific regression model for patients with at least one lipid profile measurement in the year before AF diagnosis to study the association of LDL levels with stroke rate, while adjusting for statin use. LDL levels were modeled using restricted cubic splines (RCS). Both models were adjusted for age, sex, heart failure, hypertension, diabetes, stroke or transient ischemic attack, and vascular disease at baseline, plus anticoagulation as a time-varying covariate.

Results

We studied 261,659 qualifying patients (median age 78 years, 49% female), of whom 3,954 (1.5%) developed a stroke during one-year follow-up. A total of 142,834 (54.6%) patients were treated with statins and 145,775 (55.7%) had lipid measurements before AF diagnosis. The adjusted RCS analyses (see Figure) indicated increasing hazard ratios (HRs) for stroke with increasing low-density lipoprotein (LDL) values above 1.5mmol/L. Statin use was associated with a lower stroke rate relative to non-users (hazard ratio 0.87, 95% confidence interval 0.81–0.93, p-value <0.0001).

Conclusion

LDL levels above 1.5mmol/L were independently associated with higher stroke rates in patients with AF, while statins were associated with lower stroke rates independent of anticoagulation. This suggests that LDL measurements may improve stroke risk stratification in AF, while statins may offer an underutilized pathway to lower stroke risk in AF.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): 1) Heart and stroke foundation of Canada HR for Stroke and LDL level

Racial/ethnic differences in cardiovascular outcomes in a universal healthcare system: insights from the CARTaGENE cohort

Background

While prior studies have shown racial/ethnic differences in cardiovascular (CV) outcomes within private or mixed health care systems, it remains uncertain whether inequalities in cardiovascular outcomes exist between different races and ethnicities in universal health care contexts. We aimed to determine whether there are racial/ethnicity disparities in long-term CV outcomes within a single-payer universal health care system.

Methods

The CARTaGENE study is a population-based prospective cohort study with enrollment of 19,996 individuals between 40–69 years in 2009, in the province of Quebec, Canada. Participants residing in four large metropolitan areas were randomly chosen from the provincial health insurance registry by strata of age, sex, and postal codes. Follow-up was available up to 2016. For this analysis, we retained only participants without prior known CV disease. The primary composite endpoint was time to the first CV event or intervention (CV death, acute coronary syndrome, heart failure, coronary revascularization, ischemic stroke, or peripheral vascular event or revascularization). We used unadjusted and adjusted Cox proportional hazard models to evaluate the association of self-defined race/ethnicity with the primary endpoint.

Results

There were 17,802 eligible participants with a mean age of 51 years (52.5% females) with 111,312 person-years of follow-up (median follow-up of 6.6 years). South Asian (SA) participants had the highest prevalence of diabetes mellitus (29%) and hypertension (32%). After adjustment for age and sex, SA ethnicity was associated with a 95% relative increase in risk for CV events, while East/Southeast Asian (ESA) ethnicity was associated with a 42% relative decrease in risk for CV events compared to White participants. After further adjustment for socioeconomic status and CV risk factors, ESA ethnicity remained associated with a similar decreased CV risk. In contrast, the association of SA ethnicity with increased CV risk was attenuated after full adjustment for baseline characteristics (Table 1).

Conclusions

Racial/ethnic disparities in long-term CV outcomes are present in a single-payer universal healthcare setting. ESA ethnicity was associated with a lower risk of long-term CV outcomes. Future studies are needed to corroborate the reduced risk of long-term major CV events associated with ESA ethnicity. Understanding the reasons related to potential CV protection with ESA ethnicity could facilitate endeavors to reduce long-term CV outcomes in other races/ethnicities.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): McGill Health University Center

Bovine Serum Albumin-Immobilized Black Phosphorus-Based γ-Fe2O3 Nanocomposites: A Promising Biocompatible Nanoplatform

The interactions between proteins and nanoparticles need to be fully characterized as the immobilization of proteins onto various nanoplatforms in the physiological system often results in the change of surface of the protein molecules to avoid any detrimental issues related to their biomedical applications. Hence, in this article, the successful low-temperature synthesis of a BP-based γ-Fe2O3 (IB) nanocomposite and its interactive behavior with bovine serum albumin (BSA)-a molecule with chemical similarity and high sequence identity to human serum albumin-are described. To confirm the formation of γ-Fe2O3 and the IB nanocomposite, X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy analyses of the materials were performed. Additionally, the physical interaction between BSA and the IB nanocomposite was confirmed via UV-Vis and photoluminescence spectral analyses. Finally, the biocompatibility of the BSA-immobilized IB nanocomposite was verified using an in vitro cytotoxicity assay with HCT-15 colon cancer cells. Our findings demonstrate that this newly developed nanocomposite has potential utility as a biocompatible nanoplatform for various biomedical applications.

TMEM52B suppression promotes cancer cell survival and invasion through modulating E-cadherin stability and EGFR activity

Background

TMEM52B is a novel gene broadly expressed in a variety of normal human tissues. However, the biological function of TMEM52B expression in cancer is largely unknown.

Methods

The effects of TMEM52B on tumor growth and metastasis were investigated in vitro and in vivo, and the underlying biological and molecular mechanisms involved in this process were evaluated. Clinical datasets from KmPlotter and The Cancer Genome Atlas (TCGA) were analyzed in relation to TMEM52B expression and function.

Results

Suppression of TMEM52B in colon cancer cells promoted cancer cell epithelial-mesenchymal transition (EMT), invasion, and survival in vitro. Similarly, in vivo studies showed increased tumor growth and circulating tumor cell survival (early metastasis). ERK1/2, JNK, and AKT signaling pathways were involved in TMEM52B suppression-induced invasiveness and cell survival. TMEM52B suppression promoted activation and internalization of epidermal growth factor receptor (EGFR) with enhanced downstream signaling activity, leading to enhanced cell survival and invasion. In addition, TMEM52B suppression reduced E-cadherin stability, likely due to a reduced association between it and E-cadherin, which led to enhanced β-catenin transcriptional activity. Concomitantly, TMEM52B suppression promoted generation of soluble E-cadherin fragments, contributing to the activation of EGFR. Clinical data showed that high TMEM52B expression correlated with increased patient survival in multiple types of cancer, including breast, lung, kidney, and rectal cancers, and suggested a correlation between TMEM52B and E-cadherin.

Conclusions

These findings suggest that TMEM52B is a novel modulator of the interplay between E-cadherin and EGFR. It is possible that TMEM52B functions as a tumor-suppressor that could potentially be used as a novel prognostic marker for cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01828-7.

Anti-cancer activity of the novel 2-hydroxydiarylamide derivatives IMD-0354 and KRT1853 through suppression of cancer cell invasion, proliferation, and survival mediated by TMPRSS4

Elevated expression of transmembrane serine protease 4 (TMPRSS4) correlates with poor prognosis in non-small cell lung cancer, gastric cancer, colorectal cancer, prostate cancer, and other cancer patients. Previously, we demonstrated that TMPRSS4 mediates tumor cell invasion, migration, proliferation, and metastasis. In addition, we reported novel 2-hydroxydiarylamide derivatives, IMD-0354 and KRT1853, as TMPRSS4 serine protease inhibitors. Here, we further evaluated the effects of the representative derivatives on TMPRSS4-mediated cellular function and signaling. IMD-0354 and KRT1853 inhibited cancer cell invasion, migration, and proliferation in TMPRSS4-expressing prostate, colon, and lung cancer cells. Both compounds suppressed TMPRSS4-mediated induction of Sp1/3, AP-1, and NF-κB transcription factors. Furthermore, TMPRSS4 promoted cancer cell survival and drug resistance, and both compounds enhanced anoikis sensitivity as well as reduced bcl-2 and survivin levels. Importantly, KRT1853 efficiently reduced tumor growth in prostate and colon cancer xenograft models. These results strongly recommend KRT1853 for further development as a novel anti-cancer agent.

Abstract 2028: ZEB2 promotes cancer cell survival and angiogenesis by cooperating with transcription factor Sp1

The metastatic cascade essential for tumor progression consists of local invasion, intravasation, extravasation, micrometastasis, cancer cell survival in the circulation, and metastatic colonization. In particular, epithelial-mesenchymal transition (EMT) has been demonstrated a critical process whereby epithelial cells undergo molecular changes to acquire mesenchymal phenotypes through upregulation of EMT-inducing transcription factors. We previously showed that ZEB2, through cooperation with the transcription factor Sp1, plays an important role in the transcriptional upregulation of mesenchymal genes such as integrin α5 and vimentin during cancer cell invasion. Here, we show that ZEB2 cooperates with Sp1 for promoting not only EMT and invasion but also diverse cellular functions during metastasis. ZEB2 induces expression of Sp1-regulated genes such as VEGF, survivin, bcl-2 and cyclin D1 in an Sp1-dependent manner. Collaboration between ZEB2 and Sp1 induces cancer cell survival and proliferation, endothelial cell activation, and tumor angiogenesis. Furthermore, Sp1 stabilizes ZEB2 protein, supporting the presence of a positive feedback loop between ZEB2 and Sp1. Clinical data show that ZEB2 expression was correlated to Sp1 expression, and that those factors were a crucial for predicting survival in cancer patients. Our findings demonstrate cooperative roles of ZEB2 and Sp1 in regulating cancer cell survival and angiogenesis beyond invasion during cancer progression.

Citation Format: Dongjoon Ko. ZEB2 promotes cancer cell survival and angiogenesis by cooperating with transcription factor Sp1 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2028.

TMPRSS4 induces invasion and proliferation of prostate cancer cells through induction of Slug and cyclin D1

TMPRSS4 is a novel type II transmembrane serine protease found at the cell surface that is highly expressed in pancreatic, colon, and other cancer tissues. Previously, we demonstrated that TMPRSS4 mediates tumor cell invasion, migration, and metastasis. We also found that TMPRSS4 activates the transcription factor activating protein-1 (AP-1) to induce cancer cell invasion. Here, we explored TMPRSS4-mediated cellular functions and the underlying mechanisms. TMPRSS4 induced Slug, an epithelial-mesenchymal transition (EMT)-inducing transcription factor, and cyclin D1 through activation of AP-1, composed of c-Jun and activating transcription factor (ATF)-2, which resulted in enhanced invasion and proliferation of PC3 prostate cancer cells. In PC3 cells, not only c-Jun but also Slug was required for TMPRSS4-mediated proliferation and invasion. Interestingly, Slug induced phosphorylation of c-Jun and ATF-2 to activate AP-1 through upregulation of Axl, establishing a positive feedback loop between Slug and AP-1, and thus induced cyclin D1, leading to enhanced proliferation. Using data from The Cancer Genome Atlas, we found that Slug expression positively correlated with that of c-Jun and cyclin D1 in human prostate cancers. Expression of Slug was positively correlated with that of cyclin D1 in various cancer cell lines, whereas expression of other EMT-inducing transcription factors was not. This study demonstrates that TMPRSS4 modulates both invasion and proliferation via Slug and cyclin D1, which is a previously unrecognized pathway that may regulate metastasis and cancer progression.

Abstract P1-10-02: A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results

Background: Metals have emerged as a viable therapeutic target for a new generation of anti-cancer and anti-metastatic agents. Copper, an essential trace element, serves as an important catalytic cofactor in several biological functions and has emerged as an essential factor in carcinogenesis. Among other elements, bone marrow derived VEGFR2+ endothelial progenitor cells (EPCs) and copper-dependent lysyl oxidase (LOX) are key elements in tumor progression. We hypothesized tetrathiomolybdate (TM)-associated copper depletion (CD) inhibits tumor metastases by reducing the number of EPCs and other copper dependent processes in the pre-metastatic niche. These results are an update of our previously reported study (Chan N, Willis A, Kornhauser N et al. Influencing the Tumor Microenvironment: Phase 2 Study of Copper Depletion with Tetrathiomolybdate in High Risk Breast Cancer and Preclinical Models of Lung Metastases. Clin Cancer Res. October 21, 2016) with longer follow-up.

Methods: A single arm phase II study of breast cancer (BC) patients (pts) at high risk for recurrence, defined as node+ triple negative (TNBC), stage 3 and 4 with no evidence of disease (NED) were enrolled on a trial of CD with TM. TM was given to maintain ceruloplasmin (Cp) levels between 8-16 mg/dl for two years with an extension phase or until relapse. The primary endpoint was a change in EPCs measured by flow cytometry before and during treatment. Secondary endpoints included tolerability, safety, PFS and LOXL-2 levels.

Results: Seventy-five pts received 2778 cycles of TM on the primary and extension study. The primary study treatment duration was 24 cycles (each cycle is 28 days) plus an extension phase. The median age is 51 years (range 29-66). Forty-five pts have stage 2/3 BC and 30 with stage 4 NED. Forty-eight percent of pts are TNBC and 40% of pts are stage 4 NED. Median Cp levels were monitored with each cycle. A decrease from 28 to 16 (p<0.0001) was seen after one cycle. Interestingly, TNBC pts seemed to have a greater decrease from 23.5 to 13 after one cycle. TM was well tolerated with grade 3/4 toxicities including: reversible neutropenia (2.3%), febrile neutropenia (0.04%), fatigue (0.2%). Five-year analysis showed a decrease in EPC's (p=0.004) and LOXL-2 (p<0.001). At a median follow-up of 7.1 years, the EFS for 75 pts is 71.4%. The EFS for 36 pts with TNBC is 71.7%. EFS for stage 2/3 TNBC is 83% and for stage IV TNBC is 59.3%.

Conclusions: TM is safe, well tolerated and appears to affect multiple components of the tumor microenvironment that have been identified in pre-clinical models as important for progression. Ongoing studies in banked specimens are underway to further delineate its effect on copper dependent processes necessary for metastases. Randomized trials are warranted, especially in patients who are at high risk for relapse such as those with TNBC.

Citation Format: Sahota S, Willis A, Kornhauser N, Ward M, Cobham M, Cigler T, Moore A, Andreopoulou E, Fitzpatrick V, Schneider S, Prima N, Wiener A, Ko D, De Laurentiis A, Warren JD, Rubinchik A, Mittal V, Vahdat LT. A phase II study of copper-depletion using tetrathiomolybdate in patients with breast cancer at high risk for recurrence: Updated results [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-02.

Cooperation between ZEB2 and Sp1 promotes cancer cell survival and angiogenesis during metastasis through induction of survivin and VEGF

Epithelial-mesenchymal transition (EMT) is a process implicated in tumor invasion and metastasis. During EMT, epithelial cells undergo molecular changes to acquire mesenchymal phenotypes, which are mediated by EMT-inducing transcription factors. Previously, we showed that ZEB2 cooperates with the transcription factor Sp1 to function as a transcriptional activator of vimentin, integrin α5, and cadherin-11, which promotes cancer cell invasion. We hypothesized that ZEB2, through cooperation with Sp1, would mediate diverse cellular functions beyond EMT and invasion during metastasis. ZEB2 upregulated the expression of Sp1-regulated genes such as survivin, bcl-2, cyclin D1, and vascular endothelial growth factor in an Sp1-dependent manner, resulting in increased cancer cell survival and proliferation and endothelial cell activation in vitro, and increased circulating tumor cell survival and tumor angiogenesis in vivo. In addition, Sp1 enhanced ZEB2 stability, suggesting the presence of a positive feedback loop between ZEB2 and Sp1. Clinical data showed that ZEB2 expression was positively associated with Sp1 expression, and that the expression of both of these factors had prognostic significance for predicting survival in cancer patients. This study suggests that invasion is linked to cancer cell survival and angiogenesis by ZEB2 during cancer progression, and increases our understanding of the pathways via which EMT-inducing transcription factors regulate the complex process of metastasis.

Anti-cancer Activity of Novel TM4SF5-Targeting Antibodies through TM4SF5 Neutralization and Immune Cell-Mediated Cytotoxicity

The transmembrane four L6 family member 5 (TM4SF5) protein is a novel molecular target for the prevention and treatment of hepatocellular carcinoma. TM4SF5 is highly expressed in liver, colon, esophageal, and pancreatic cancers and is implicated in tumor progression. Here, we screened monoclonal antibodies that specifically bound to the extracellular loop 2 (EC2) of TM4SF5 from a phage-displayed murine antibody (single-chain variable fragment; scFv) library. We constructed and characterized chimeric antibodies, Ab27 and Ab79, of scFv fused with Fc domain of human IgG1. The affinity (K_D) of Ab27 and Ab79 for soluble EC2 was approximately 9.2 nM and 16.9 nM, respectively, as determined by surface plasmon resonance analysis. Ab27 and Ab79 efficiently bound to native TM4SF5 on the cell surface were internalized into the cancer cells, leading to a decrease in cell surface TM4SF5. Ab27 and Ab79 inhibited the proliferation and invasion of TM4SF5-positive liver and colon cancer cells and reduced FAK and c-Src phosphorylation. Ab27 and Ab79 also enhanced anoikis sensitivity and reduced survivin. Ab27 mediated antibody-dependent cell-mediated cytotoxicity in vitro. Ab27 and Ab79 efficiently inhibited tumor growth in a liver cancer xenograft model. These results strongly support the further development of Ab27 as a novel anti-cancer agent in the clinic.

Laparoscopic living donor nephrectomy: is there a difference between using a left or a right kidney?

BACKGROUND

The goal of this study was to review the results of 279 laparoscopic living donor nephrectomies (LLDN) regarding outcomes of using the left or the right kidney.

METHODS

Among 279 patients who underwent LLDN between August 1998 and April 2009, 260 underwent a left (group L) and 19, a right (group R) nephrectomy. The two groups were compared regarding intra- and postoperative parameters, including pre- and postoperative renal function, length of surgery, conversion to an open approach, delayed graft function, and complications.

RESULTS

There were no significant differences between the two groups regarding preoperative glomerular filtration rate (L = 129.5 ± 32 mL/min versus group R = 127.3 ± 26 mL/min), length of surgery (group L = 228 ± 58 minutes versus group R = 226 ± 62 minutes group), postoperative donor creatinine (group L = 1.36 ± 0.9 mg/dL versus group R = 1.48 ± 0.8 mg/dL), conversion to open (group L = 6.6% versus group R = 5.3%), delayed graft function (group L = 7.2% versus group R = 6.3%) and recipient postoperative creatinine at 1 month (group L = 1.54 ± 1.4 mg/dL versus group R = 1.32 ± 1.1 mg/dL). There were three intraoperative donor complications in group L (bleeding in one donor required transfusion), and none in group R. Similarly, there was a great albeit not a significant difference in the number of major postoperative donor complications among group L (n = 16) versus group R (n = 2). The right kidney was chosen because of the number of vessels (n = 5), presence of cysts (n = 5), size and renal function (n = 6), presence of renal stones (n = 2), and tortuous ureter (n = 1). The reasons for conversion to open included bleeding, anatomic issues, and presence of adhesions. It should be noted that during the last 3 years there were no conversions to open, whereas the only conversion among group R was the first case.

CONCLUSIONS

Intra- and postoperative parameters were comparable between the groups. Considering the limitations of the small sample size of right LLDNs in this study, it appears that it is as safe and effective as a left procedure. The learning curve is extremely important, as can be seen by the lack of conversion in the last 3 years.

Perampanel: expanding therapeutic options for patients with medically refractory secondary generalized convulsive seizures

To evaluate the efficacy of adjunctive, once-daily perampanel against secondarily generalized (SG) seizures in three Phase III trials (studies 304, 305, and 306) and their extension (study 307). The Phase III studies enrolled patients (≥ 12 years) with uncontrolled partial-onset seizures despite treatment with 1-3 concomitant antiepileptic drugs. Patients completing the core Phase III studies were eligible for the extension study. Endpoints included median percent change in SG seizure frequency, 50% responder (proportion of patients achieving a ≥ 50% reduction in SG seizure frequency), 75% response, and seizure-freedom rates. In total, 1480 patients were randomized and treated in the three perampanel Phase III trials. At baseline, 71.9% of placebo-treated and 68.4% of perampanel-treated patients had a history of SG seizures. In the individual core Phase III studies, perampanel (4-12 mg) reduced seizure frequency and improved responder rates. Consistent with this, in pooled analyses of the Phase III data, the median percent change in SG seizure frequency was -48.6%, -62.9%, and -53.3% with perampanel 4, 8, and 12 mg, respectively, vs -19.4% with placebo; 50% responder rates were 49.3%, 60.5%, and 53.7% vs 37.0% with placebo. More perampanel-treated patients had ≥ 75% reductions in SG seizure frequency, and seizure-freedom rates improved, compared with placebo. Improvements in seizure frequency and responder rate were maintained during the extension study. Perampanel consistently demonstrated efficacy against SG seizures when assessed using various endpoints. Furthermore, reductions in seizure frequency and improvements in responder rate were sustained with long-term perampanel treatment.

Detection of bursts and pauses in spike trains

Midbrain dopaminergic neurons in vivo exhibit a wide range of firing patterns. They normally fire constantly at a low rate, and speed up, firing a phasic burst when reward exceeds prediction, or pause when an expected reward does not occur. Therefore, the detection of bursts and pauses from spike train data is a critical problem when studying the role of phasic dopamine (DA) in reward related learning, and other DA dependent behaviors. However, few statistical methods have been developed that can identify bursts and pauses simultaneously. We propose a new statistical method, the Robust Gaussian Surprise (RGS) method, which performs an exhaustive search of bursts and pauses in spike trains simultaneously. We found that the RGS method is adaptable to various patterns of spike trains recorded in vivo, and is not influenced by baseline firing rate, making it applicable to all in vivo spike trains where baseline firing rates vary over time. We compare the performance of the RGS method to other methods of detecting bursts, such as the Poisson Surprise (PS), Rank Surprise (RS), and Template methods. Analysis of data using the RGS method reveals potential mechanisms underlying how bursts and pauses are controlled in DA neurons.

Evaluating the antipsychotic profile of the preferential PDE10A inhibitor, papaverine

RATIONALE

Prepulse inhibition (PPI) is an operational measure of sensorimotor gating that is deficient in schizophrenia patients. In rats, PPI deficits induced by dopamine (DA) agonists are reversed by antipsychotics. Inhibition of the striatum-rich phosphodiesterase (PDE)10A may represent a novel antipsychotic mechanism. Previous studies were controversial, showing antipsychotic-like profiles in measures of PPI for the preferential PDE10A inhibitor papaverine (PAP) but not the novel PDE10A inhibitor TP-10.

OBJECTIVE

The aim of the study was to evaluate the antipsychotic profile of PAP in rats using PPI.

MATERIALS AND METHODS

PPI deficits were induced in rats by apomorphine (APO; 0.1, 0.5 mg/kg) or D: -amphetamine (AMPH; 4 mg/kg). PAP (3, 10, 30 mg/kg) or haloperidol (HAL; 0.1 mg/kg) was tested against these agonists in Sprague-Dawley (SD) or Wistar (WI) rats. Prepulse intervals ranged from 10 to 120 ms. Further tests evaluated the effects of PAP on spontaneous locomotion, AMPH (1 mg/kg)-induced hyperlocomotion, and core body temperature (T degrees ).

RESULTS

HAL reversed APO-induced PPI deficits but PAP failed to reverse APO- and AMPH-induced PPI deficits at all doses, strains, pretreatment times, and prepulse intervals. PAP (30 mg/kg) significantly reduced AMPH hyperlocomotion in SD rats, and a similar pattern was detected in WI rats. This PAP dose also strongly reduced spontaneous locomotion and T degrees in SD rats.

CONCLUSION

Our study does not support an antipsychotic-like profile of PAP in dopaminergic PPI models.

Persistence of restricted CD4 T cell expansions in SIV-infected macaques resistant to SHIV89.6P superinfection

Attempts to evaluate the protective effect of live attenuated SIV vaccine strains have yielded variable results depending on the route of immunization, the level of attenuation, the level of divergence between the vaccine candidate and the challenge. The protective mechanisms induced by these vaccines are still not well understood. In an effort to address whether the diversity of the CD4+ T cell repertoire in cynomolgus macaques plays a role in the immunological protection following SIVmacC8 infection, we have performed a longitudinal follow-up of the CD4 repertoire by heteroduplex tracking assay in macaques mock-infected or infected with either the attenuated SIVmacC8 or its homologous SIVmacJ5 and challenged with simian-human immunodeficiency virus (SHIV89.6P). Viral load and CD4 absolute counts were determined in these animals and the presence of SHIV89.6P virus in challenged animals was evaluated by PCR and serology. In all macaques that were protected against the challenging virus, we demonstrated a reduced diversity in the CD4+ TRBV repertoire and a few dominant CD4+ T cell clones during early primary infection. In contrast, CD4 TRBV repertoire in unprotected macaques remained highly diverse. Moreover, some of the CD4 T cell clones that were expanded during primary SIV infection re-emerged after challenge suggesting their role in protection against the challenging virus. These results underline the importance of maintaining the CD4 T cell repertoire developed during acute infection and point to the restriction of the CD4 response to the vaccine as a correlate of protection.

Comparison of the E3 and L3 regions for arming oncolytic adenoviruses to achieve a high level of tumor-specific transgene expression

Arming oncolytic adenoviral vectors with anticancer transgenes that can be expressed in a tumor-selective manner may enable the engineering of vectors with increased potency, while retaining their safety profile. Armed oncolytic adenoviral vectors were constructed in which transgene expression has been linked via modified splice acceptor sequences that did not necessitate the deletion of any part of the adenoviral genome. Several oncolytic adenoviral vectors were compared in which the transgene was inserted in place of either the E3 or the L3 region. While all vectors had similar viral growth and cytotoxicity characteristics, the highest level of transgene expression was observed from a vector in which the transgene had been inserted downstream of the L3 23K protease gene, the Ad-23K-GM vector. Notably, no transgene expression occurred with this vector in the absence of DNA replication either in vitro or in vivo. In contrast, viruses in which the transgene was inserted into E3 locations exhibited a low level of transgene expression even in the absence of DNA replication. In summary, by utilizing the L3 region for arming oncolytic viruses, higher levels of tumor-specific transgene expression can be obtained without the need to delete any parts of the viral genome.

The kidney transplant program at the Massachusetts general hospital

Between February 1963 and December 2000, 1,627 kidney transplants were performed at the Massachusetts General Hospital. The majority (62%) were from cadaveric donors, although in recent years (1996-2000) 52% have been allografts from living donors, with an increase in living unrelated donors. The introduction of CsA and OKT3 in 1984 was associated with a significant improvement in actuarial renal allograft survival, although a persistent late attrition of allografts continues beyond the first year after transplantation. As reported in other centers, current actuarial survival for living unrelated allografts is superior to that of cadaveric allografts, and is quite similar to that observed in recipients of non-HLA identical living-related transplants. Our preliminary laparoscopic donor nephrectomy experience is encouraging as excellent allograft survival and function has been observed, with minimal morbidity associated with the procedure and a low rate of conversion to open nephrectomy. Recent changes in immunosuppressive protocols have resulted in lower early acute rejection rates, however the incidence of delayed graft function remains unchanged in cadaveric renal transplantation. The role of humoral immunity in allograft rejection has been progressively clarified and new approaches to control donor specific alloantibody production have been shown to be effective. Current clinical studies are ongoing to determine the optimal type and dose of calcineurin inhibitors beyond the first year after transplantation and to study whether avoidance of steroids is safe and feasible. Finally, an innovative tolerance induction protocol using the mixed chimerism approach has been successfully accomplished in selected patients with end-stage renal disease secondary to multiple myeloma. These encouraging observations emphasize that major changes from current immunosuppressive regimens are likely to occur over the next few years as more approaches to tolerance induction are explored clinically.

Conversion of oxacillin-resistant staphylococci from heterotypic to homotypic resistance expression

Staphylococci that acquire the mecA gene are usually resistant to beta-lactam antibiotics (methicillin or oxacillin resistance). mecA encodes a penicillin-binding protein (PBP 2a) that has a reduced affinity for beta-lactams. In some isolates with methicillin or oxacillin resistance, only a small proportion (< or =0.1%) of the population expresses resistance to > or =10 microg of oxacillin per ml (heterotypic resistance [HeR]), while in other isolates most of the population expresses resistance (homotypic resistance [HoR]). In the present study, growth of Staphylococcus aureus or Staphylococcus epidermidis strains with HeR in concentrations of oxacillin (0.3 to 0.7 microg/ml) that produced a fall or a lag in optical density converted the strains from the HeR to the HoR phenotype. The conversion from the HeR to the HoR phenotype appeared to be due to the selection of a highly resistant mutant population, as determined by fluctuation analysis and the failure of populations with HoR to revert to HeR after 60 generations of growth in antibiotic-free media. The frequencies of conversion were as high as 10(-3) to 10(-2). Conversion to HoR required an intact mecA gene and an increase in the level of mecA transcription since no highly resistant subpopulation could be selected after growth in oxacillin when mecA transcription was constitutively repressed or when mecA had been inactivated. In addition, in both S. epidermidis and S. aureus the level of resistance to vancomycin, which also acts directly on the staphylococcal cell wall, was greater among convertants with HoR than their isogenic parents. The conversion of a population from HeR to HoR involves the selection of a mutation(s) that occurs at a high frequency and most likely requires abundant PBP 2a.

A novel human cancer culture model for the study of prostate cancer

Research into molecular and genetic mechanisms underlying prostate carcinogenesis would be greatly advanced by in vitro models of prostate tumors representing primary tumors. We have successfully established an immortalized human prostate epithelial (HPE) cell culture derived from a primary tumor with telomerase. The actively proliferating early passaged RC-58T cells were transduced through infection with a retrovirus vector expressing the human telomerase catalytic subunit (hTERT). A high level of telomerase was detected in RC-58T/hTERT cells but not RC-58T cells. RC-58T/hTERT cells are currently growing well at passage 50, whereas RC-58T cells senesced at passage 7. RC-58T/hTERT cells exhibit transformed morphology. More importantly, these immortalized cells showed anchorage-independent growth as they formed colonies in soft agar and grew above the agar layer. Expression of androgen-regulated prostate specific gene NKX3.1 and epithelial specific cytokeratin 8 (CK8) but not prostate specific antigen (PSA) and androgen receptor was detected in RC-58T/hTERT cells. Prostate stem cell antigen (PSCA) and p16 were also expressed in this cell line. RC-58T/hTERT cells showed growth inhibition when exposed to retinoic acid and transforming growth factor (TGF)-beta1 known potent inhibitors of prostate epithelial cell growth. A number of chromosome alterations were observed including the loss of chromosomes Y, 3p, 10p, 17p, 18q and the gain of chromosomes 16 and 20. These results demonstrate that this primary tumor-derived HPE cell line retained its transformed phenotypes and should allow studies to elucidate molecular and genetic alterations involved in prostate cancer. This is the first documented case of an established human prostate cancer cell line from a primary tumor of a prostate cancer patient with telomerase.

Occupational allergic contact dermatitis in Singapore

Singapore has a resident population of 3,000,000 and a workforce of 1,780,000. Most are employed in manufacturing, services and commerce (245,000). From 1996 to 1998, 3472 cases were notified to the Ministry of Manpower and confirmed as occupational diseases. Noise-induced hearing loss accounted for 82% of cases, while only 11% of cases were industrial dermatitis. Occupational allergic contact dermatitis was not common, comprising approximately one third of the 369 cases of industrial dermatitis that were notified. However, we believe that the majority of cases are not notified to the authorities. The main occupational contact allergens were chromates, nickel, rubber chemicals, cutting fluids and resins. Most affected workers were from the construction, electronics and metalworking industries. Case series of occupational dermatoses among electronics and metal workers have been published. Of the cases of occupational dermatoses among electronics workers seen at a tertiary dermatological centre, 41% of 149 had allergic contact dermatitis (ACD). The commonest allergens were nickel, resins and rubber chemicals. In another case series of 252 metalworkers seen at the same dermatological centre, 23% suffered from ACD. The common allergens were metals and cutting fluids. Besides the common causes of ACD, unusual allergens have also been described. One example is ACD to grasses, which is seen mainly among military personnel. Population studies have been conducted in several industries. A survey of 2567 electronics workers revealed a 2% point prevalence of ACD. Of the occupationally relevant cases, 46 were nickel sensitive, 7 reacted to colophony, and 1 case to epoxy resin. A study of 272 prefabrication construction workers showed a 14% prevalence rate of occupational dermatitis. Of the 38 cases, 42% were ACD to chromates and rubber chemicals. Occupational ACD in Singapore is not as uncommon as the reported statistics suggest. Population-based reports, which overcome the problem of under-notification, show that the prevalence is variable in different industries.