Chengcheng Hu

Hypoxia Triggers Hedgehog-Mediated Tumor–Stromal Interactions in Pancreatic Cancer

Pancreatic cancer is characterized by a desmoplastic reaction that creates a dense fibroinflammatory microenvironment, promoting hypoxia and limiting cancer drug delivery due to decreased blood perfusion. Here, we describe a novel tumor-stroma interaction that may help explain the prevalence of desmoplasia in this cancer. Specifically, we found that activation of hypoxia-inducible factor-1α (HIF-1α) by tumor hypoxia strongly activates secretion of the sonic hedgehog (SHH) ligand by cancer cells, which in turn causes stromal fibroblasts to increase fibrous tissue deposition. In support of this finding, elevated levels of HIF-1α and SHH in pancreatic tumors were determined to be markers of decreased patient survival. Repeated cycles of hypoxia and desmoplasia amplified each other in a feed forward loop that made tumors more aggressive and resistant to therapy. This loop could be blocked by HIF-1α inhibition, which was sufficient to block SHH production and hedgehog signaling. Taken together, our findings suggest that increased HIF-1α produced by hypoxic tumors triggers the desmoplasic reaction in pancreatic cancer, which is then amplified by a feed forward loop involving cycles of decreased blood flow and increased hypoxia. Our findings strengthen the rationale for testing HIF inhibitors and may therefore represent a novel therapeutic option for pancreatic cancer.

Atazanavir Pharmacokinetics With and Without Tenofovir during Pregnancy

Background:Few data are available describing atazanavir exposure during pregnancy, especially when used in combination with tenofovir, whose coadministration with atazanavir results in decreased atazanavir exposure. Design:International Maternal Pediatric Adolescent AIDS Clinical Trials 1026s is an ongoing, prospective, nonblinded study of antiretroviral pharmacokinetics in HIV-infected pregnant women that included 2 cohorts receiving atazanavir/ritonavir 300 mg/100 mg once daily, either with or without tenofovir. Methods:Intensive steady-state 24-hour pharmacokinetic profiles were performed during the third trimester and at 6-12 weeks postpartum. Atazanavir was measured by reverse-phase high-performance liquid chromatography (detection limit 0.047 mcg/mL). Pharmacokinetic targets were the estimated 10th percentile atazanavir area under the concentration versus time curve [(AUC): 29.4 mcg·hr·mL−1] in nonpregnant historical controls (mean AUC = 57 mcg·hr·mL−1) and a trough concentration of 0.15 mcg/mL, the concentration target used in therapeutic drug monitoring programs. Results:Median atazanavir AUC was reduced during the third trimester compared with postpartum for subjects not receiving tenofovir (41.9 vs. 57.9 mcg·hr·mL−1, P = 0.02) and for subjects receiving tenofovir (28.8 vs. 39.6 mcg·hr·mL−1, P = 0.04). During the third trimester, AUC was below the target in 33% (6 of 18) of women not receiving tenofovir and 55% (11 of 20) of women receiving tenofovir. Trough concentration was below the target in 6% (1 of 18) of women not receiving tenofovir and 15% (3 of 20) of women receiving tenofovir. The median (range) ratio of cord blood/maternal atazanavir concentration in 29-paired samples was 0.18 (0-0.45). Conclusions:Atazanavir exposure is reduced by pregnancy and by concomitant tenofovir use. A dose increase of atazanavir/ritonavir to 400 mg/100 mg may be necessary in pregnant women to ensure atazanavir exposure equivalent to that seen in nonpregnant adults.

Down-regulation of Yes Associated Protein 1 expression reduces cell proliferation and clonogenicity of pancreatic cancer cells.

Background The Hippo pathway regulates organ size by inhibiting cell proliferation and promoting cell apoptosis upon its activation. The Yes Associated Protein 1 (YAP1) is a nuclear effector of the Hippo pathway that promotes cell growth as a transcription co-activator. In human cancer, the YAP1 gene was reported as amplified and over-expressed in several tumor types. Methods Immunohistochemical staining of YAP1 protein was used to assess the expression of YAP1 in pancreatic tumor tissues. siRNA oligonucleotides were used to knockdown the expression of YAP1 and their effects on pancreatic cancer cells were investigated using cell proliferation, apoptosis, and anchorage-independent growth assays. The Wilcoxon signed-rank, Pearson correlation coefficient, Kendalls Tau, Spearmans Rho, and an independent two-sample t (two-tailed) test were used to determine the statistical significance of the data. Results Immunohistochemistry studies in pancreatic tumor tissues revealed YAP1 staining intensities were moderate to strong in the nucleus and cytoplasm of the tumor cells, whereas the adjacent normal epithelial showed negative to weak staining. In cultured cells, YAP1 expression and localization was modulated by cell density. YAP1 total protein expression increased in the nuclear fractions in BxPC-3 and PANC-1, while it declined in HPDE6 as cell density increased. Additionally, treatment of pancreatic cancer cell lines, BxPC-3 and PANC-1, with YAP1-targeting siRNA oligonucleotides significantly reduced their proliferation in vitro. Furthermore, treatment with YAP1 siRNA oligonucleotides diminished the anchorage-independent growth on soft agar of pancreatic cancer cells, suggesting a role of YAP1 in pancreatic cancer tumorigenesis. Conclusions YAP1 is overexpressed in pancreatic cancer tissues and potentially plays an important role in the clonogenicity and growth of pancreatic cancer cells.

p38 MAP kinase plays a functional role in UVB-induced mouse skin carcinogenesis.

UVB irradiation of epidermal keratinocytes results in the activation of the p38 mitogen‐activated protein kinase (MAPK) pathway and subsequently activator protein‐1 (AP‐1) transcription factor activation and cyclooxygenase‐2 (COX‐2) expression. AP‐1 and COX‐2 have been shown to play functional roles in UVB‐induced mouse skin carcinogenesis. In this study, the experimental approach was to express a dominant negative p38α MAPK (p38DN) in the epidermis of SKH‐1 hairless mice and assess UVB‐induced AP‐1 activation, COX‐2 expression, and the skin carcinogenesis response in these mice compared to wild‐type littermates. We observed a significant inhibition of UVB‐induced AP‐1 activation and COX‐2 expression in p38DN transgenic mice, leading to a significant reduction of UVB‐induced tumor number and growth compared to wild‐type littermates in a chronic UVB skin carcinogenesis model. A potential mechanism for this reduction in tumor number and growth rate is an inhibition of chronic epidermal proliferation, observed as reduced Ki‐67 staining in p38DN mice compared to wild‐type. Although we detected no difference in chronic apoptotic rates between transgenic and nontransgenic mice, analysis of acutely irradiated mice demonstrated that expression of the p38DN transgene significantly inhibited UVB‐induced apoptosis of keratinocytes. These results counter the concerns that inhibition of p38 MAPK in a chronic situation could compromise the ability of the skin to eliminate potentially tumorigenic cells. Our data indicate that p38 MAPK is a good target for pharmacological intervention for UV‐induced skin cancer in patients with sun damaged skin, and suggest that inhibition of p38 signaling reduces skin carcinogenesis by inhibiting COX‐2 expression and proliferation of UVB‐irradiated cells.

A Phase 2a Study of Topical Perillyl Alcohol Cream for Chemoprevention of Skin Cancer

The chemopreventive and antitumor properties of perillyl alcohol (POH) that were studied preclinically indicate that topical POH inhibits both UVB-induced murine skin carcinogenesis (squamous cell tumor models) and 7,12-dimethylbenz(a)anthracene–induced murine melanoma (transgenic models involving tyrosinase-driven Ras). A previous phase 1 clinical trial in participants with normal-appearing skin showed that topical POH cream was well tolerated at a dose of 0.76% (w/w). Here, we performed a 3-month, double-blind, randomized, placebo-controlled phase 2a trial of two different doses of topical POH in individuals with sun-damaged skin. Participants applied POH cream twice daily to each dorsal forearm. Baseline and end-of-study biopsies were taken from each participant to evaluate whether the topical application of POH was effective in reversing actinic damage as evidenced by normalization of quantitative skin histopathologic scores and change in nuclear chromatin pattern as measured by karyometric analysis. There was a borderline reduction in the histopathologic score of the lower-dose POH group compared with the placebo (P = 0.1), but this was not observed in the high-dose group. However, in the high-dose group, a statistically significant reduction in the proportion of nuclei deviating from normal was observed by the use of karyometric analysis (P < 0.01). There was no statistical significance shown in the lower-dose group. No changes were observed in p53 expression, cellular proliferation (by proliferating cell nuclear antigen expression), or apoptosis in either treatment group compared with the placebo group. These results suggest that whereas our karyometric analyses can detect a modest effect of POH in sun-damaged skin, improved delivery into the epidermis may be necessary. Cancer Prev Res; 3(2); 160–9

Implementation of a Regional Telephone Cardiopulmonary Resuscitation Program and Outcomes After Out-of-Hospital Cardiac Arrest

IMPORTANCE Bystander cardiopulmonary resuscitation (CPR) significantly improves survival from out-of-hospital cardiac arrest but is provided in less than half of events on average. Telephone CPR (TCPR) can significantly increase bystander CPR rates and improve clinical outcomes. OBJECTIVE To investigate the effect of a TCPR bundle of care on TCPR process measures and outcomes. DESIGN, SETTING, AND PARTICIPANTS A prospective, before-after, observational study of adult patients with out-of-hospital cardiac arrest not receiving bystander CPR before the 9-1-1 call between October 1, 2010, and September 30, 2013. INTERVENTIONS A TCPR program, including guideline-based protocols, telecommunicator training, data collection, and feedback, in 2 regional dispatch centers servicing metropolitan Phoenix, Arizona. Audio recordings of out-of-hospital cardiac arrest calls were audited and linked with emergency medical services and hospital outcome data. MAIN OUTCOMES AND MEASURES Survival to hospital discharge and functional outcome at hospital discharge. RESULTS There were 2334 out-of-hospital cardiac arrests (798 phase 1 [P1] and 1536 phase 2 [P2]) in the study group; 64% (1499) were male, and the median age was 63 years (age range, 9-101 years; interquartile range, 51-75 years). Provision of TCPR increased from 43.5% in P1 to 52.8% in P2 (P < .001), yielding an increase of 9.3% (95% CI, 4.9%-13.8%). The median time to first chest compression decreased from 256 seconds in P1 to 212 seconds in P2 (P < .001). All rhythm survival was significantly higher in P2 (184 of 1536 [12.0%]) compared with P1 (73 of 798 [9.1%]), with an adjusted odds ratio (aOR) of 1.47 (95% CI, 1.08-2.02; P = .02) in a logistic regression model and an adjusted difference in absolute survival rates (adjusted rate difference) of 3.1% (95% CI, 1.5%-4.9%). Survival for patients with a shockable initial rhythm significantly improved in P2 (107 of 306 [35.0%]) compared with P1 (42 of 170 [24.7%]), with an aOR of 1.70 (95% CI, 1.09-2.65; P = .02) and an adjusted rate difference of 9.6% (95% CI, 4.8%-14.4%). The rate of favorable functional outcome was significantly higher in P2 (127 of 1536 [8.3%]; 95% CI, 6.9%-9.8%) than in P1 (45 of 798 [5.6%]; 95% CI, 4.1%-7.5%), with an aOR of 1.68 (95% CI, 1.13-2.48; P = .01) and an adjusted rate difference of 2.7% (95% CI, 1.3%-4.4%). CONCLUSIONS AND RELEVANCE Implementation of a guideline-based TCPR bundle of care was independently associated with significant improvements in the provision and timeliness of TCPR, survival to hospital discharge, and survival with favorable functional outcome.

Polymorphic variation in the GC and CASR genes and associations with vitamin D metabolite concentration and metachronous colorectal neoplasia.

Background: Vitamin D levels and calcium intake have been associated with risk of colorectal neoplasia, and genetic variation in vitamin D pathway genes may affect circulating vitamin D metabolite concentrations and/or risk for colorectal lesions. This study evaluated associations between polymorphic variation in the Gc-globulin (GC) and calcium-sensing receptor (CASR) and odds for metachronous colorectal neoplasia and vitamin D metabolite concentrations. Methods: Participants from the Ursodeoxycholic Acid (UDCA) and Wheat Bran Fiber (WBF) trials (n = 1,439) were analyzed using a single-nucleotide polymorphism (SNP) tagging approach, with a subset (n = 404) of UDCA trial participants for whom vitamin D metabolite concentrations were also available. A total of 25 GC and 35 CASR tagSNPs were evaluated using multiple statistical methods. Results: Principal components analyses did not reveal gene-level associations between GC or CASR and colorectal neoplasia; however, a significant gene-level association between GC and 25(OH)D concentrations (P < 0.01) was observed. At the individual SNP level and following multiple comparisons adjustments, significant associations were observed between seven GC (rs7041, rs222035, rs842999, rs1155563, rs12512631, rs16846876, and rs1746825) polymorphisms and circulating measures of 25(OH)D (adjusted P < 0.01) and CASR SNP rs1042636 and proximal colorectal neoplasia (adjusted P = 0.01). Conclusions: These results show a possible association between variation in CASR and odds of colorectal neoplasia as well as the potential role of variation in GC with circulating 25(OH)D concentrations. Impact: Additional research is warranted to determine the mechanism of GC genotype in influencing 25(OH)D concentrations and to further elucidate the role of CASR in colorectal neoplasia. Cancer Epidemiol Biomarkers Prev; 21(2); 368–75. ©2011 AACR.

Association between polymorphic variation in VDR and RXRA and circulating levels of vitamin D metabolites.

The vitamin D metabolite 1,25(OH)2D is the bioactive ligand of the vitamin D receptor (VDR). VDR forms a heterodimer with the retinoid X receptors (RXRs) that when bound to ligand influences the transcriptional control of genes that regulate circulating levels of vitamin D metabolites. Whether genetic variation in VDR or RXRA affects circulating levels of 1,25(OH)2D or 25(OH)D has not been established. We used a single nucleotide polymorphism (SNP) tagging approach to evaluate the association between SNPs in VDR and RXRA and serum levels of 1,25(OH)2D and 25(OH)D. A total of 42 tagSNPs in VDR and 32 in RXRA were analyzed in a sample of 415 participants. Principal components analyses revealed a gene-level association between RXRA and serum 1,25(OH)2D concentrations (P=0.01), but not 25(OH)D. No gene-level association was found for VDR with either serum biomarker. At the single-SNP level, a significant positive trend was observed for increasing 1,25(OH)2D levels with each additional copy of the A allele for RXRA SNP rs9409929 (P-trend=0.003). After a multiple comparisons adjustment, no individual SNP in VDR or RXRA was significantly associated with either outcome. These results demonstrate an association between genetic variation in RXRA and 1,25(OH)2D serum concentrations.

Acute cardiovascular effects of firefighting and active cooling during rehabilitation.

Objectives: To determine the cardiovascular and hemostatic effects of fire suppression and postexposure active cooling. Methods: Forty-four firefighters were evaluated before and after a 12-minute live-fire drill. Next, 50 firefighters performing the same drill were randomized to undergo postfire forearm immersion in 10°C water or standard rehabilitation. Results: In the first study, heart rate and core body temperature increased and serum C-reactive protein decreased but there were no significant changes in fibrinogen, sE-selectin, or sL-selectin. The second study demonstrated an increase in blood coagulability, leukocyte count, factors VIII and X, cortisol, and glucose, and a decrease in plasminogen and sP-selectin. Active cooling reduced mean core temperature, heart rate, and leukocyte count. Conclusions: Live-fire exposure increased core temperature, heart rate, coagulability, and leukocyte count; all except coagulability were reduced by active cooling.

Plaques and tangles as well as Lewy-type alpha synucleinopathy are associated with formed visual hallucinations

OBJECTIVE Previous research has linked complex or formed visual hallucinations (VH) to Lewy-type alpha-synucleinopathy (LTS) in neocortical and limbic areas. As Alzheimers disease pathology often co-occurs with LTS, we questioned whether this pathology - amyloid plaques and neurofibrillary tangles - might also be linked to VH. METHODS We performed a semi-quantitative neuropathological study across brainstem, limbic, and cortical structures in subjects with a documented clinical history of VH and a clinicopathological diagnosis of Parkinsons disease (PD), Alzheimers disease (AD), or dementia with Lewy bodies (DLB). 173 subjects - including 50 with VH and 123 without VH - were selected from the Arizona Study of Aging and Neurodegenerative Disorders. Clinical variables examined included the Mini-mental State Exam, Hoehn & Yahr stage, and total dopaminergic medication dose. Neuropathological variables examined included total and regional LTS and plaque and tangle densities. RESULTS A significant relationship was found between the density of LTS and the presence of VH in PD, AD, and DLB. Plaque and tangle densities also were associated with VH in PD (p = .003 for plaque and p = .004 for tangles) but not in AD, where densities were high regardless of the presence of hallucinations. Furthermore, with DLB cases excluded, comorbidity of PD and AD was significantly more prevalent among subjects + VH than subjects -VH (p < .001). CONCLUSION These findings suggest that both AD and PD neuropathology contribute to the pathogenesis of VH. Incident VH could be predictive of concomitant AD/PD pathology even when criteria are not met for a second diagnosis.