Phospholipase C Isozymes Are Deregulated in Colorectal Cancer – Insights Gained from Gene Set Enrichment Analysis of the Transcriptome

Colorectal cancer (CRC) is one of the most common cancer types in developed countries. To identify molecular networks and biological processes that are deregulated in CRC compared to normal colonic mucosa, we applied Gene Set Enrichment Analysis to two independent transcriptome datasets, including a total of 137 CRC and ten normal colonic mucosa samples. Eighty-two gene sets as described by the Kyoto Encyclopedia of Genes and Genomes database had significantly altered gene expression in both datasets. These included networks associated with cell division, DNA maintenance, and metabolism. Among signaling pathways with known changes in key genes, the “Phosphatidylinositol signaling network”, comprising part of the PI3K pathway, was found deregulated. The downregulated genes in this pathway included several members of the Phospholipase C protein family, and the reduced expression of two of these, PLCD1 and PLCE1, were successfully validated in CRC biopsies (n = 70) and cell lines (n = 19) by quantitative analyses. The repression of both genes was found associated with KRAS mutations (P = 0.005 and 0.006, respectively), and we observed that microsatellite stable carcinomas with reduced PLCD1 expression more frequently had TP53 mutations (P = 0.002). Promoter methylation analyses of PLCD1 and PLCE1 performed in cell lines and tumor biopsies revealed that methylation of PLCD1 can contribute to reduced expression in 40% of the microsatellite instable carcinomas. In conclusion, we have identified significantly deregulated pathways in CRC, and validated repression of PLCD1 and PLCE1 expression. This illustrates that the GSEA approach may guide discovery of novel biomarkers in cancer

Induction of Immune Mediators in Glioma and Prostate Cancer Cells by Non-Lethal Photodynamic Therapy

BACKGROUND: Photodynamic therapy (PDT) uses the combination of photosensitizing drugs and harmless light to cause selective damage to tumor cells. PDT is therefore an option for focal therapy of localized disease or for otherwise unresectable tumors. In addition, there is increasing evidence that PDT can induce systemic anti-tumor immunity, supporting control of tumor cells, which were not eliminated by the primary treatment. However, the effect of non-lethal PDT on the behavior and malignant potential of tumor cells surviving PDT is molecularly not well defined. METHODOLOGY/PRINCIPAL FINDINGS: Here we have evaluated changes in the transcriptome of human glioblastoma (U87, U373) and human (PC-3, DU145) and murine prostate cancer cells (TRAMP-C1, TRAMP-C2) after non-lethal PDT in vitro and in vivo using oligonucleotide microarray analyses. We found that the overall response was similar between the different cell lines and photosensitizers both in vitro and in vivo. The most prominently upregulated genes encoded proteins that belong to pathways activated by cellular stress or are involved in cell cycle arrest. This response was similar to the rescue response of tumor cells following high-dose PDT. In contrast, tumor cells dealing with non-lethal PDT were found to significantly upregulate a number of immune genes, which included the chemokine genes CXCL2, CXCL3 and IL8/CXCL8 as well as the genes for IL6 and its receptor IL6R, which can stimulate proinflammatory reactions, while IL6 and IL6R can also enhance tumor growth. CONCLUSIONS: Our results indicate that PDT can support anti-tumor immune responses and is, therefore, a rational therapy even if tumor cells cannot be completely eliminated by primary phototoxic mechanisms alone. However, non-lethal PDT can also stimulate tumor growth-promoting autocrine loops, as seen by the upregulation of IL6 and its receptor. Thus the efficacy of PDT to treat tumors may be improved by controlling unwanted and potentially deleterious growth-stimulatory pathways

Vowel reduction in word-final position by early and late Spanish-English bilinguals

Vowel reduction is a prominent feature of American English, as well as other stress-timed languages. As a phonological process, vowel reduction neutralizes multiple vowel quality contrasts in unstressed syllables. For bilinguals whose native language is not characterized by large spectral and durational differences between tonic and atonic vowels, systematically reducing unstressed vowels to the central vowel space can be problematic. Failure to maintain this pattern of stressed-unstressed syllables in American English is one key element that contributes to a ?foreign accent? in second language speakers. Reduced vowels, or ?schwas,? have also been identified as particularly vulnerable to the co-articulatory effects of adjacent consonants. The current study examined the effects of adjacent sounds on the spectral and temporal qualities of schwa in word-final position. Three groups of English-speaking adults were tested: Miami-based monolingual English speakers, early Spanish-English bilinguals, and late Spanish-English bilinguals. Subjects performed a reading task to examine their schwa productions in fluent speech when schwas were preceded by consonants from various points of articulation. Results indicated that monolingual English and late Spanish-English bilingual groups produced targeted vowel qualities for schwa, whereas early Spanish-English bilinguals lacked homogeneity in their vowel productions. This extends prior claims that schwa is targetless for F2 position for native speakers to highly-proficient bilingual speakers. Though spectral qualities lacked homogeneity for early Spanish-English bilinguals, early bilinguals produced schwas with near native-like vowel duration. In contrast, late bilinguals produced schwas with significantly longer durations than English monolinguals or early Spanish-English bilinguals. Our results suggest that the temporal properties of a language are better integrated into second language phonologies than spectral qualities. Finally, we examined the role of nonstructural variables (e.g. linguistic history measures) in predicting native-like vowel duration. These factors included: Age of L2 learning, amount of L1 use, and self-reported bilingual dominance. Our results suggested that different sociolinguistic factors predicted native-like reduced vowel duration than predicted native-like vowel qualities across multiple phonetic environments

Oncogenicity of the developmental transcription factor Sox9

SOX9 [sex-determining region Y (SRY)-box 9 protein], a high mobility group box transcription factor, plays critical roles during embryogenesis and its activity is required for development, differentiation, and lineage commitment in various tissues including the intestinal epithelium. Here, we present functional and clinical data of a broadly important role for SOX9 in tumorigenesis. SOX9 was overexpressed in a wide range of human cancers, where its expression correlated with malignant character and progression. Gain of SOX9 copy number is detected in some primary colorectal cancers. SOX9 exhibited several pro-oncogenic properties, including the ability to promote proliferation, inhibit senescence, and collaborate with other oncogenes in neoplastic transformation. In primary mouse embryo fibroblasts and colorectal cancer cells, SOX9 expression facilitated tumor growth and progression whereas its inactivation reduced tumorigenicity. Mechanistically, we have found that Sox9 directly binds and activates the promoter of the polycomb Bmi1, whose upregulation represses the tumor suppressor Ink4a/Arf locus. In agreement with this, human colorectal cancers showed a positive correlation between expression levels of SOX9 and BMI1 and a negative correlation between SOX9 and ARF in clinical samples. Taken together, our findings provide direct mechanistic evidence of the involvement of SOX9 in neoplastic pathobiology, particularly, in colorectal cancer. ©2012 AACR.link_to_OA_fulltex

Impaired expression of indoleamine 2, 3-dioxygenase in monocyte-derived dendritic cells in response to Toll-like receptor-7/8 ligands

The effects of immunostimulatory RNAs (isRNAs) on the expression of immuno-suppressive factors are largely unknown. Indoleamine 2,3-dioxygenase (IDO) is a key negative regulator of immune responses and it has been implicated in hampering immunity against tumours. Here we show that the activation of Toll-like receptors (TLR)-7/8 with isRNAs or R848, a specific ligand for TLR7/8, can induce IDO expression in human monocytes, but not in monocyte-derived dendritic cells (moDC). In contrast to TLR7/8 agnosists, treatment of the same moDC with interferon-γ-induced IDO expression. Treatment of monocytes with 2′-O-methyl uridine-modified isRNAs alone does not induce IDO, but totally abrogated the effects of unmodified isRNAs. Like isRNAs, synthetic viral RNAs and cytomegalovirus (CMV) induced IDO in monocytes, whereas TLR2 ligand lipopeptide Pam3Cys exhibited no effect. Furthermore, IDO positive monocytes suppressed autologous T-cell activation. Collectively, these data indicate for first time that the potency of TLR7/8 signalling pathways to induce IDO expression in monocytes is silenced when the cells are programmed to differentiate into dendritic cells. The immunosuppressive properties of IDO might confer an advantage to CMV-infected monocytes to escape T-cell responses. The findings that 2′-O-methyl modified RNAs can block isRNA-induced IDO expression would facilitate the design of new TLR inhibitors

Forests and Water Provision - What is the relationship?

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