A novel GNAS-mutated human induced pluripotent stem cell model for understanding GNAS-mutated tumors

A Rare Skeletal Disorder, Fibrous Dysplasia: A Review of Its Pathogenesis and Therapeutic Prospects

Fibrous dysplasia (FD) is a rare, non-hereditary skeletal disorder characterized by its chronic course of non-neoplastic fibrous tissue buildup in place of healthy bone. A myriad of factors have been associated with its onset and progression. Perturbation of cell-cell signaling networks and response outputs leading to disrupted building blocks, incoherent multi-level organization, and loss of rigid structural motifs in mineralized tissues are factors that have been identified to participate in FD induction. In more recent years, novel insights into the unique biology of FD are transforming our understandings of its pathology, natural discourse of the disease, and treatment prospects. Herein, we built upon existing knowledge with recent findings to review clinical, etiologic, and histological features of FD and discussed known and potential mechanisms underlying FD manifestations. Subsequently, we ended on a note of optimism by highlighting emerging therapeutic approaches aimed at either halting or ameliorating disease progression.

Current status of molecular diagnostic approaches using liquid biopsy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers, and developing an efficient and reliable approach for its early-stage diagnosis is urgently needed. Precancerous lesions of PDAC, such as pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMN), arise through multiple steps of driver gene alterations in KRAS, TP53, CDKN2A, SMAD4, or GNAS. Hallmark mutations play a role in tumor initiation and progression, and their detection in bodily fluids is crucial for diagnosis. Recently, liquid biopsy has gained attention as an approach to complement pathological diagnosis, and in addition to mutation signatures in cell-free DNA, cell-free RNA, and extracellular vesicles have been investigated as potential diagnostic and prognostic markers. Integrating such molecular information to revise the diagnostic criteria for pancreatic cancer can enable a better understanding of the pathogenesis underlying inter-patient heterogeneity, such as sensitivity to chemotherapy and disease outcomes. This review discusses the current diagnostic approaches and clinical applications of genetic analysis in pancreatic cancer and diagnostic attempts by liquid biopsy and molecular analyses using pancreatic juice, duodenal fluid, and blood samples. Emerging knowledge in the rapidly advancing liquid biopsy field is promising for molecular profiling and diagnosing pancreatic diseases with significant diversity.

Research and Therapeutic Approaches in Stem Cell Genome Editing by CRISPR Toolkit

The most widely used genome editing toolkit is CRISPR (clustered regularly interspaced short palindromic repeats). It provides the possibility of replacing and modifying DNA and RNA nucleotides. Furthermore, with advancements in biological technology, inhibition and activation of the transcription of specific gene(s) has become possible. Bioinformatics tools that target the evolution of CRISPR-associated protein 9 (Cas9) turn this protein into a vehicle that is specific for a DNA or RNA region with single guide RNA (sgRNA). This toolkit could be used by researchers to investigate the function of stem cell gene(s). Here, in this review article, we cover recent developments and applications of this technique in stem cells for research and clinical purposes and discuss different CRISPR/Cas technologies for knock-out, knock-in, activation, or inhibition of gene expression. Additionally, a comparison of several deliveries and off-target detecting strategies is discussed.

Intraductal oncocytic papillary neoplasm arising in Peutz-Jeghers Syndrome bile duct: a unique case report

BACKGROUND

Peutz-Jeghers syndrome (PJS) is a rare, autosomal dominant disorder caused by germline mutations of STK11/LKB1, with an increased risk of tumors at multiple sites. Intraductal oncocytic papillary neoplasm (IOPN) is a unique subtype of intraductal papillary neoplasm of the bile duct (IPNB) defined by a premalignant neoplasm with intraductal papillary or villous growth of biliary-type epithelium. IOPN has a distinct mutation profile compared with both IPNB and intraductal papillary mucinous neoplasm (IPMN).

CASE PRESENTATION

We herein describe the case of a 44-year-old woman who presented as polyps in the intestinal lumen of sigmoid colon and a 3.1 × 2.1 cm mass in the left lobe of liver. Gross feature revealed a cystic papillary mass and the neoplasm had a clear boundary with the surrounding liver tissue. Histology revealed complex papillary structures, a small amount of fine fibrovascular cores and immunohistochemistry showed extensive positive for MUC5AC, MUC6, CD117. Therefore, histological and immunohistochemical examination of the liver tumor suggested the diagnosis of IOPN. Next-generation sequencing (NGS) revealed other than STK11 germline mutation, the tumor also harbors GNAS somatic mutation at codon 478 and EGFR amplification.

CONCLUSION

To our knowledge, this is the first report of IOPN arising in PJS. This case enlarges the spectrum of PJS related tumors and genetic rearrangements in IOPN.

Melanin interference toxicity or transgenerational toxicity of organic UV filter ethylhexyl salicylate on zebrafish

With the improvement of human health awareness, the production and usage of sunscreens have increased dramatically, and their active ingredients, organic ultraviolet (UV) filters (OUVFs), have the potential to induce melanin abnormalities in aquatic organisms due to their UV-absorbing properties as they enter the aquatic environment directly with the washing of skin during water activities. In this paper, the melanin interference toxicity or transgenerational toxicity effects of typical OUVFs ethylhexyl salicylate (EHS) on zebrafish (Danio rerio) were investigated based on transcriptomic sequencing technology. Results showed that EHS induced significant enrichment of the melanin-related pathway cAMP signaling pathway in parental skin tissue through UV absorption, with sensitive genes identified as melanocortin 1 receptor, protein kinase A catalytic subunit beta a, calcium/calmodulin-dependent protein kinase II delta 2, adenylate cyclase 1 and G protein subunit alpha I a. qRT-PCR verification results showed that EHS may inhibit the expression of the melanin master regulator microphthalmia-associated transcription factor a (mitfa) and its induced signaling cascade mitf-tyrosinase (tyr)-dopachrome tautomerase (dct)-tyrosinase related protein 1 (tyrp1) by inducing abnormal expression of the above sensitive genes, thereby reducing melanogenesis. After reproduction, the melanin interference effect of EHS on the parents can be carried over to offsprings through maternal inheritance of abnormally expressed mitfa and parental transfer of pollutants, as evidenced by significant enrichment of melanogenesis pathway, abnormal expression of sensitive genes mitfa, tyr, dct and tyrp1b and significant decreases in melanin content and spinal melanin area. These findings revealed the specific melanin interference toxicity of OUVFs with UV-absorbing properties, facilitating a comprehensive ecological risk assessment of OUVFs and providing scientific support for the management of new pollutants.

Mutant GNAS limits tumor aggressiveness in established pancreatic cancer via antagonizing the KRAS-pathway

BACKGROUND

Mutations in GNAS drive pancreatic tumorigenesis and frequently occur in intraductal papillary mucinous neoplasm (IPMN); however, their value as a therapeutic target is yet to be determined. This study aimed at evaluating the involvement of mutant GNAS in tumor aggressiveness in established pancreatic cancer.

METHODS

CRISPR/Cas9-mediated GNAS R201H silencing was performed using human primary IPMN-associated pancreatic cancer cells. The role of oncogenic GNAS in tumor maintenance was evaluated by conducting cell culture and xenograft experiments, and western blotting and transcriptome analyses were performed to uncover GNAS-driven signatures.

RESULTS

Xenografts of GNAS wild-type cells were characterized by a higher Ki-67 labeling index relative to GNAS-mutant cells. Phenotypic alterations in the GNAS wild-type tumors resulted in a significant reduction in mucin production accompanied by solid with massive stromal components. Transcriptional profiling suggested an apparent conflict of mutant GNAS with KRAS signaling. A significantly higher Notch intercellular domain (NICD) was observed in the nuclear fraction of GNAS wild-type cells. Meanwhile, inhibition of protein kinase A (PKA) induced NICD in GNAS-mutant IPMN cells, suggesting that NOTCH signaling is negatively regulated by the GNAS-PKA pathway. GNAS wild-type cells were characterized by a significant invasive property relative to GNAS-mutant cells, which was mediated through the NOTCH regulatory pathway.

CONCLUSIONS

Oncogenic GNAS induces mucin production, not only via MUC2 but also via MUC5AC/B, which may enlarge cystic lesions in the pancreas. The mutation may also limit tumor aggressiveness by attenuating NOTCH signaling; therefore, such tumor-suppressing effects must be considered when therapeutically inhibiting the GNAS pathway.