Human cytomegalovirus infection of THP-1 derived macrophages reveals strain-specific regulation of actin dynamics

Human cytomegalovirus (HCMV) remains latent in cells of the myeloid lineage after primary infection. The THP-1 monocytic cell line is conditionally permissive for infection and has been used primarily to study the process of HCMV reactivation when the cells are induced to differentiate. In the present report, we characterized lytic infection in THP-1 derived macrophages using two strains of HCMV, Towne and BAC-derived TR. Our findings indicate that these cells express viral genes of all three kinetic classes and produce extracellular virus, but that there is a delay in these processes relative to productively infected fibroblasts. Importantly, our studies in THP-1 derived macrophages revealed strain-specific differences in pp65 trafficking and actin dynamics. Based on these observations, our studies indicate that differentiated THP-1 cells can serve as a valuable model for lytic infection.

P1-07-19: Analysis of HER2−Status in Breast Cancer by Mass Spectrometry in Archival, Formalin-Fixed Tissues

HER2 (ERBB2) is overexpressed in about 25% of breast cancers and predicts clinical benefit from trastuzumab, as well as response to anthracycline-based chemotherapy. Fluorescence in situ hybridization (FISH) to detect HER2 gene copy number and immunohistochemistry (IHC) to detect HER2 protein levels are approved by the FDA to identify HER2−positive (H2) tumors. However, the 2007 ASCO/CAP report concluded that approximately 20% of HER2 testing may be inaccurate. Further, the available data did not clearly demonstrate clear superiority of either IHC or FISH as a predictor of benefit from anti-HER2 therapy. Discordance between these methods is as high as 5%. Thus, novel complementary quantitative methods for interrogating HER2 expression in tumors are needed.

Targeted protein analysis by multiple reaction monitoring mass spectrometry (MRM-MS) offers a powerful approach to configure assays for specific proteins without using antibodies. Our studies using this platform have demonstrated applicability to formalin-fixed, paraffin-embedded (FFPE) specimens. In the current studies, we used this approach to measure signals from two tryptic peptides specific to HER2, one each from the extracellular and intracellular domains, selected from among 28 candidates based on their signal intensity and sharpness of their chromatographic profiles. Preliminary studies with a HER2−overexpressing BT474 xenograft in mice demonstrated quantitation and detected previously reported HER2 ectodomain shedding. Subsequent analysis of FFPE tissue from five H2 and five triple-negative (TN) tumors yielded measurement of at least 1 femptomole of receptor for H2 tumors and less than 0.2 femptomole of receptor for TN tumors per microgram of digest analyzed. If we assume 200 picograms of protein per cell, the results suggest 110,00 to 468,000 receptors per cell in the H2 tumors and only 2,000 to 14,000 receptors per cell in the TN tumors. Despite significant biological variability in receptor levels measured among the specimens of each type, a clear separation of the H2 and TN tumors was achieved based on the peptide quantitation. This preliminary study demonstrates the potential of MRM-MS in FFPE tissue to provide an alternate approach to IHC-based protein analysis. MRM-MS offers the potential for more, accurate and robust HER2 quantification in clinical breast cancer tissues. The next phase of this work will encompass a larger sample set, including tumors with equivocal and negative FISH and/or IHC test results. Correlation with response to anti-Her2 therapy will be performed in samples with available follow-up data.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-19.

The abolishment of anesthesia-induced cognitive impairment by timely protection of mitochondria in the developing rat brain: the importance of free oxygen radicals and mitochondrial integrity

Early exposure to general anesthesia (GA) causes developmental neuroapoptosis in the mammalian brain and long-term cognitive impairment. Recent evidence suggests that GA also causes functional and morphological impairment of the immature neuronal mitochondria. Injured mitochondria could be a significant source of reactive oxygen species (ROS), which, if not scavenged in timely fashion, may cause excessive lipid peroxidation and damage of cellular membranes. We examined whether early exposure to GA results in ROS upregulation and whether mitochondrial protection and ROS scavenging prevent GA-induced pathomorphological and behavioral impairments. We exposed 7-day-old rats to GA with or without either EUK-134, a synthetic ROS scavenger, or R(+) pramipexole (PPX), a synthetic aminobenzothiazol derivative that restores mitochondrial integrity. We found that GA causes extensive ROS upregulation and lipid peroxidation, as well as mitochondrial injury and neuronal loss in the subiculum. As compared to rats given only GA, those also given PPX or EUK-134 had significantly downregulated lipid peroxidation, preserved mitochondrial integrity, and significantly less neuronal loss. The subiculum is highly intertwined with the hippocampal CA1 region, anterior thalamic nuclei, and both entorhinal and cingulate cortices; hence, it is important in cognitive development. We found that PPX or EUK-134 co-treatment completely prevented GA-induced cognitive impairment. Because mitochondria are vulnerable to GA-induced developmental neurotoxicity, they could be an important therapeutic target for adjuvant therapy aimed at improving the safety of commonly used GAs.

Abstract P6-04-05: Digital Quantification of Post-Neoadjuvant Chemotherapy Breast Tumor RNA Reveals a Basal-Derived Gene Signature Associated with Post-Treatment Ki67

Neoadjuvant chemotherapy (NAC) leads to a pathological complete response (pCR) in -20% of patients with breast cancer. The rest of the patients exhibit residual disease (RD) in the breast after NAC and are more likely to have a metastatic recurrence. Recent data show that tumor cell proliferation, as measured by Ki67 in the residual post-NAC cancer, can inform clinical outcome. We hypothesized that RD after NAC will harbor different gene expression as a function of Ki67 index. A 2nd hypothesis is that identification of key alterations in tumors with post-NAC high Ki67 will identify molecules or networks that can be therapeutically targeted in the immediate post-operative setting to eradicate clinically silent micro-metastases.

We utilized Nanostring digital RNA quantification to measure the expression of 350 genes in 49 post-NAC residual breast cancers. The cohort was enriched for triple-negative cancers (24/49). Genes were selected based on relevance to breast cancer, published prognostic signatures, and our own unsupervised class discovery approach from existing microarray data. For the selected gene sets, we included a chemo-resistance signature (CHEMO), a stroma signature (STROMA), and a WNT/metastasis signature (WNT/MET). For the unsupervised analysis, publicly available pre-treatment microarray data from chemotherapy-treated ER-breastcancers that did not achieve pCR were clustered and the two most prominent groups were used to select a 250 gene set (CLUSTER). Ki67 was assessed in the RD for the 49 tumors and correlated to absolute RNA counts of the 350 selected genes.

Ki67 was strongly associated with subtype as defined by the PAM50 classifier (P<0.0001). Basal tumors demonstrated the highest Ki67, followed by Luminal B, HER2, and Luminal A tumors (median = 63.5, 27, 22.6, and 5.5%, respectively). The CHEMO signature correlated inversely with Ki67 index (p=2.5e-8): paradoxically, genes positively associated with a higher probability of pCR correlated with a high Ki67 in the post-NAC specimens. Thus, chemotherapy-enriched tumors demonstrate distinct and unexpected gene expression patterns after treatment. The WNT/MET and STROMA gene sets showed significant trends with similar directionality to the CHEMO gene set. Our CLUSTER gene set was highly predictive of Ki67 (p=3.6e-6) and robustly associated with basal subtype (p=2.6e-13). MELK, an anti-apoptotic kinase involved in activation of Bcl-G was positively associated with a high Ki67 independently of tumor subtype (p=0.035 and p=0.045 in luminal and basal, respectively). In luminal tumors, high expression of BRCA1, BRCA2, and RRM2 was associated with high Ki67 (p=0.027, 0.016, and 7e-5, respectively), while reduced DUSP4 expression, a MAPK phosphatase, was predictive of high Ki67 in basal post-NAC tumors (p=6e-4).

Existing gene expression predictors built on pre-treatment data did not match expected patterns in chemotherapy-enriched tumors. Breast cancer subtype was strongly associated with a chemotherapy-refractory high Ki67 index in the surgically removed tumors. Further, the assessment of gene expression patterns in RD may be important in ascertaining the molecular underpinnings of aggressive disease. Thus, our defined gene signature may offer insights into molecular targets in patients who do not achieve pCR after NAC.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-04-05.

Symmetry-based scalable lossless compression of 3D medical image data

We propose a novel symmetry-based technique for scalable lossless compression of 3D medical image data. The proposed method employs the 2D integer wavelet transform to decorrelate the data and an intraband prediction method to reduce the energy of the sub-bands by exploiting the anatomical symmetries typically present in structural medical images. A modified version of the embedded block coder with optimized truncation (EBCOT), tailored according to the characteristics of the data, encodes the residual data generated after prediction to provide resolution and quality scalability. Performance evaluations on a wide range of real 3D medical images show an average improvement of 15% in lossless compression ratios when compared to other state-of-the art lossless compression methods that also provide resolution and quality scalability including 3D-JPEG2000, JPEG2000, and H.264/AVC intra-coding.

Occupational health and safety status of indigenous and Latino farmworkers in Oregon

Exposure to pesticides poses great risk to agricultural workers and their families. Of the approximately 174,000 agricultural workers in Oregon, studies estimate that up to 40% of the workers in Oregon are indigenous and may be particularly vulnerable to the health risks of working in pesticide treated areas. Surveys conducted with Oregon farmworkers suggest that Latino and indigenous farmworkers differ demographically and may have diverse occupational and health needs. All Latino workers reported Spanish as their native language, while indigenous workers spoke several different native languages. Latino workers were employed mostly in orchards (28%) and nurseries (24%), while indigenous workers were mostly pickers (40%). Indigenous farmworkers reported less frequent suitable occupational safety training, and potentially less knowledge of the health consequences of pesticides. Addressing the barriers to obtaining pesticide health and safety information is of primary importance, given the changing demographics of farmworkers in Oregon. This article concludes with a discussion of these findings and the programmatic activities that have been implemented in Oregon to improve farmworkers' understanding of hazards and rights associated with agricultural work.

Subversion of cell cycle regulatory pathways

Human cytomegalovirus (HCMV) has evolved numerous strategies to commandeer the host cell for producing viral progeny. The virus manipulates host cell cycle pathways from the early stages of infection to stimulate viral DNA replication at the expense of cellular DNA synthesis. At the same time, cell cycle checkpoints are by-passed, preventing apoptosis and allowing sufficient time for the assembly of infectious virus.

Nonlinear analyses of cell proliferation in the central nervous system reveal stochastic and deterministic components

This paper analyzes the dynamics of cell proliferation in the developing central nervous system. Three different algorithms, Fano factor, Allan factor and detrended fluctuations analysis, are used to estimate de scaling exponent of space numerical series obtained by recording the number and position of proliferating cells along the cephalic-caudal axis of the system. It can be concluded that the dynamics of proliferation involves two component: (a) a random noncorrelated stochastic component representing a basal proliferating activity uniformly distributed along the cephalic-caudal axis and (b) a deterministic nonstationary component that imposes a defined global trend to the process. The deterministic nonstationary trend can be interpreted as the effect of a controlling influence operating along the cephalic-caudal axis. This result indicates that the proliferative activity is spatially organized along the cephalic-caudal axis of the system.

3,4-Methylenedioxymethamphetamine increases pro-interleukin-1beta production and caspase-1 protease activity in frontal cortex, but not in hypothalamus, of Dark Agouti rats: role of interleukin-1beta in neurotoxicity

3,4-Methylenedioxymethamphetamine (ecstasy) increases mature interleukin-1beta production in rat brain shortly after injection. This effect is a consequence of the 3,4-methylenedioxymethamphetamine-induced hyperthermia and is reduced when rats are maintained at low ambient room temperature. Since interleukin-1beta is generated as an inactive 31-kDa precursor protein and processed into mature form by caspase-1, we have now examined the effect of 3,4-methylenedioxymethamphetamine on pro-interleukin-1beta production and caspase-1-like protease activity in the hypothalamus and frontal cortex of Dark Agouti rats. 3,4-Methylenedioxymethamphetamine increased the immunoreactivity of pro-interleukin-1beta in frontal cortex, not in hypothalamus, 3 h and 6 h after administration. Caspase-1-like protease activity was increased in frontal cortex 3 h after 3,4-methylenedioxymethamphetamine injection compared with saline-treated animals. 3,4-Methylenedioxymethamphetamine did not modify the expression of pro-caspase-1 but increased the immunoreactivity for the caspase-1 active cleavage product (p20) in frontal cortex 3 h after dosing. No change on caspase-1-like protease activity was observed in hypothalamus. The basal immunoreactivity of pro-interleukin-1beta and caspase-1-like protease activity was higher in the hypothalamus than in frontal cortex of control (saline-treated) animals. These data indicate that 3,4-methylenedioxymethamphetamine alters, in a region-specific manner, the mechanisms which regulate interleukin-1beta production in the brain of Dark Agouti rats and suggest that the release of interleukin-1beta in hypothalamus may be regulated independently of caspase-1 activation. Administration (i.c.v.) of interleukin-1beta enhanced the 3,4-methylenedioxymethamphetamine-induced long-term loss of brain 5-HT parameters and immediate hyperthermia. Neither of these effects was observed when interleukin-1beta was given into hippocampus. These results indicate that exogenous interleukin-1beta potentiates 3,4-methylenedioxymethamphetamine neurotoxicity as a consequence of its effect on body temperature and suggest that the 3,4-methylenedioxymethamphetamine-induced rise in interleukin-1beta levels could in turn contribute to the maintenance of 3,4-methylenedioxymethamphetamine-induced hyperthermia and subsequent neurotoxicity.

Diagnosis of pit and fissure caries using frequency-domain infrared photothermal radiometry and modulated laser luminescence

Non-intrusive, non-contacting frequency-domain photothermal radiometry (FD-PTR or PTR) and frequency-domain luminescence (FD-LUM or LUM) have been used with 659- and 830-nm laser sources to assess the pits and fissures on the occlusal surfaces of human teeth. Fifty-two human teeth were examined with simultaneous measurements of PTR and LUM and were compared to conventional diagnostic methods including continuous (dc) luminescence (DIAGNOdent), visual inspection and radiographs. To compare each method to the others, sensitivities and specificities were calculated by using histological observations as the gold standard. With the combined criteria of four PTR and LUM signals (two amplitudes and two phases), it was found that the sensitivity of this method was much higher than any of the other methods used in this study, whereas the specificity was comparable to that of dc luminescence diagnostics. Therefore, PTR and LUM, as a combined technique, has the potential to be a reliable tool to diagnose early pit and fissure caries and could provide detailed information about deep lesions. Using the longer wavelength (830-nm) laser source, it has been shown that detection of deeper subsurface lesions than the 659-nm probe provides is possible.