bims-myxlip 2021-05-09 papers

Issue of 2021–05–09
five papers selected by
Laura Mannarino, Humanitas Research

Endocrinology. 2021 May 08. pii: bqab096. [Epub ahead of print]

An RNAi screening of clinically relevant transcription factors regulating human adipogenesis and adipocyte metabolism.

Christel Björk, Narmadha Subramanian, Jianping Liu, Juan Ramon Acosta, Beatriz Tavira, Anders B Eriksson, Peter Arner, Jurga Laurencikiene.

OBJECTIVE: Healthy hyperplasic (many but smaller fat cells) white adipose tissue (WAT) expansion is mediated by recruitment, proliferation and/or differentiation of new fat cells. This process (adipogenesis) is controlled by transcriptional programs mostly identified in rodents. A systemic investigation of adipogenic human transcription factors (TFs) that are relevant for metabolic conditions has not been revealed previously.
METHODS: TFs regulated in WAT by obesity, adipose morphology, cancer cachexia and insulin resistance were selected from microarrays. Their role in differentiation of human adipose tissue-derived stem cells (hASC) was investigated by RNA interference (RNAi) screen. Lipid accumulation, cell number and lipolysis were measured for all screened factors (148 TFs). RNA (RNAseq), protein (western blot) expression, insulin and catecholamine responsiveness were examined in hASC following siRNA treatment of selected target TFs.
RESULTS: Analysis of TFs regulated by metabolic conditions in human WAT revealed that many of them belong to adipogenesis-regulating pathways. The RNAi screen identified 39 genes that affected fat cell differentiation in vitro, where 11 genes were novel. Of the latter JARID2 stood out as being necessary for formation of healthy fat cell metabolic phenotype by regulating expression of multiple fat-cell phenotype-specific genes.
CONCLUSIONS: This comprehensive RNAi screening in hASC suggests that a large proportion of WAT TFs that are impacted by metabolic conditions might be important for hyperplastic adipose tissue expansion. The screen also identified JARID2 as a novel TF essential for the development of functional adipocytes.

Keywords: JARID2; RNAi; RNAseq; adipogenesis; human adipose-derived stem cells; insulin resistance; obesity

DOI: https://doi.org/10.1210/endocr/bqab096

Nucleic Acids Res. 2021 May 03. pii: gkab293. [Epub ahead of print]

The multi-functionality of UHRF1: epigenome maintenance and preservation of genome integrity.

Monica Mancini, Elena Magnani, Filippo Macchi, Ian Marc Bonapace.

During S phase, the cooperation between the macromolecular complexes regulating DNA synthesis, epigenetic information maintenance and DNA repair is advantageous for cells, as they can rapidly detect DNA damage and initiate the DNA damage response (DDR). UHRF1 is a fundamental epigenetic regulator; its ability to coordinate DNA methylation and histone code is unique across proteomes of different species. Recently, UHRF1's role in DNA damage repair has been explored and recognized to be as important as its role in maintaining the epigenome. UHRF1 is a sensor for interstrand crosslinks and a determinant for the switch towards homologous recombination in the repair of double-strand breaks; its loss results in enhanced sensitivity to DNA damage. These functions are finely regulated by specific post-translational modifications and are mediated by the SRA domain, which binds to damaged DNA, and the RING domain. Here, we review recent studies on the role of UHRF1 in DDR focusing on how it recognizes DNA damage and cooperates with other proteins in its repair. We then discuss how UHRF1's epigenetic abilities in reading and writing histone modifications, or its interactions with ncRNAs, could interlace with its role in DDR.

DOI: https://doi.org/10.1093/nar/gkab293

Aging (Albany NY). 2021 May 04. 13

Gene expression profiles for an immunoscore model in bone and soft tissue sarcoma.

Jingyuan Fan, Xinyi Qin, Rongquan He, Jie Ma, Qingjun Wei.

BACKGROUND: Immune infiltration is a prognostic marker to clinical outcomes in various solid tumors. However, reports that focus on bone and soft tissue sarcoma are rare. The study aimed to analyze and identify how immune components influence prognosis and develop a novel prognostic system for sarcomas.
METHODS: We retrieved the gene expression data from 3 online databases (GEO, TCGA, and TARGET). The immune fraction was estimated using the CIBERSORT algorithm. After that, we re-clustered samples by K-means and constructed immunoscore by the least absolute shrinkage and selection operator (LASSO) Cox regression model. Next, to confirm the prognostic value, nomograms were constructed.
RESULTS: 334 samples diagnosed with 8 tumor types (including osteosarcoma) were involved in our analysis. Patients were next re-clustered into three subgroups (OS, SAR1, and SAR2) through immune composition. Survival analysis showed a significant difference between the two soft tissue groups: patients with a higher proportion of CD8+ T cells, macrophages M1, and mast cells had favorable outcomes (p=0.0018). Immunoscore models were successfully established in OS and SAR2 groups consisting of 12 and 9 cell fractions, respectively. We found immunosocre was an independent factor for overall survival time. Patients with higher immunoscore had poor prognosis (p<0.0001). Patients with metastatic lesions scored higher than those counterparts with localized tumors (p<0.05).
CONCLUSIONS: Immune fractions could be a useful tool for the classification and prognosis of bone and soft tissue sarcoma patients. This proposed immunoscore showed a promising impact on survival prediction.

Keywords: CIBERSORT; K-means; immune infiltrating; lasso regression; sarcoma

DOI: https://doi.org/10.18632/aging.202956

Cancers (Basel). 2021 Apr 29. pii: 2153. [Epub ahead of print]13(9):

PPARs and Tumor Microenvironment: The Emerging Roles of the Metabolic Master Regulators in Tumor Stromal-Epithelial Crosstalk and Carcinogenesis.

Hong Sheng Cheng, Yun Sheng Yip, Eldeen Kai Yi Lim, Walter Wahli, Nguan Soon Tan.

Peroxisome proliferator-activated receptors (PPARs) have been extensively studied for more than three decades. Consisting of three isotypes, PPARα, γ, and β/δ, these nuclear receptors are regarded as the master metabolic regulators which govern many aspects of the body energy homeostasis and cell fate. Their roles in malignancy are also increasingly recognized. With the growing interest in crosstalk between tumor stroma and epithelium, this review aims to highlight the current knowledge on the implications of PPARs in the tumor microenvironment. PPARγ plays a crucial role in the metabolic reprogramming of cancer-associated fibroblasts and adipocytes, coercing the two stromal cells to become substrate donors for cancer growth. Fibroblast PPARβ/δ can modify the risk of tumor initiation and cancer susceptibility. In endothelial cells, PPARβ/δ and PPARα are pro- and anti-angiogenic, respectively. Although the angiogenic role of PPARγ remains ambiguous, it is a crucial regulator in autocrine and paracrine signaling of cancer-associated fibroblasts and tumor-associated macrophages/immune cells. Of note, angiopoietin-like 4 (ANGPTL4), a secretory protein encoded by a target gene of PPARs, triggers critical oncogenic processes such as inflammatory signaling, extracellular matrix derangement, anoikis resistance and metastasis, making it a potential drug target for cancer treatment. To conclude, PPARs in the tumor microenvironment exhibit oncogenic activities which are highly controversial and dependent on many factors such as stromal cell types, cancer types, and oncogenesis stages. Thus, the success of PPAR-based anticancer treatment potentially relies on innovative strategies to modulate PPAR activity in a cell type-specific manner.

Keywords: cancer-associated adipocyte; cancer-associated fibroblast; metabolic reprogramming; peroxisome proliferation-activated receptor; tumor-associated macrophage

DOI: https://doi.org/10.3390/cancers13092153

Cancer Med. 2021 May 07.

Cardiac safety of trabectedin monotherapy or in combination with pegylated liposomal doxorubicin in patients with sarcomas and ovarian cancer.

Robin L Jones, Thomas J Herzog, Shreyaskumar R Patel, Margaret von Mehren, Scott M Schuetze, Brian A Van Tine, Robert L Coleman, Roland Knoblauch, Spyros Triantos, Peter Hu, Waleed Shalaby, Tracy McGowan, Bradley J Monk, George D Demetri.

BACKGROUND: As with other alkylating agents, cardiac dysfunction can occur with trabectedin therapy for advanced soft tissue sarcomas (STS) or recurrent ovarian cancer (ROC) where treatment options for advanced disease are still limited. Cardiac safety for trabectedin monotherapy (T) for STS or in combination with pegylated liposomal doxorubicin (T+PLD) for ROC was evaluated in this retrospective postmarketing regulatory commitment.
METHODS: Patient data for multiple cardiac-related treatment-emergent adverse events (cTEAEs) were evaluated in pooled analyses of ten phase 2 trials, one phase 3 trial in STS (n = 982), and two phase 3 trials in ROC (n = 1231).
RESULTS: Multivariate analyses on pooled trabectedin data revealed that cardiovascular medical history (risk ratio [RR (95% CI)]: 1.90 [1.24-2.91]; p = 0.003) and age ≥65 years (RR [95% CI]: 1.78 [1.12-2.83]; p = 0.014) were associated with increased risk for cTEAEs. Multivariate analyses showed increased risk of experiencing cTEAEs with T+PLD compared to PLD monotherapy (RR [95% CI]: 2.70 [1.75-4.17]; p < 0.0001) and with history of prior cardiac medication (RR [95% CI]: 1.88 [1.16-3.05]; p = 0.010).
CONCLUSIONS: For patients with STS or ROC who still have limited treatment options, trabectedin may be initiated after carefully considering benefit versus risk. Trial Registration (ClinicalTrials.gov): NCT01343277; NCT00113607; NCT01846611.

Keywords: anthracycline; cardiac toxicity; chemotherapy; patient outcomes; soft tissue sarcomas

DOI: https://doi.org/10.1002/cam4.3903