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

Clinical outcomes and molecular characteristics of lung-only and liver-only metastatic pancreatic cancer: results from a real-world evidence database

BACKGROUND

Previous research demonstrates longer survival for patients with lung-only metastatic pancreatic adenocarcinoma (mPDAC) compared to liver-only mPDAC. The objective of this study is to understand the survival differences, impact of chemotherapy, and associated genomic features of mPDAC that is isolated to either the liver or lung.

PATIENTS AND METHODS

Longitudinal clinical outcomes and molecular sequencing data were retrospectively analyzed across 831 patients with PDAC across all stages whose tumors first metastasized to the liver or lung. Survival differences were evaluated using Cox regression. Mutational frequency differences were evaluated using Fisher's exact test.

RESULTS

Median overall survival (mOS) was shorter in patients with liver-only metastasis (1.3y [1.2-1.4], n = 689) compared to lung-only metastasis (2.1y [1.9-2.5], n = 142) (P = .000000588, HR = 2.00 [1.53-2.63]. Survival differences were observed regardless of choice of 1st-line standard-of-care therapy. For 5-fluorouracil-based therapies, mOS for liver-only mPDAC was 1.4y [1.3-1.6] (n = 211) compared to 2.1y [1.8-3.3] for lung-only mPDAC (n = 175) (P = .008113, HR = 1.75 [1.16-2.65]). For gemcitabine/nab-paclitaxel therapy, mOS for liver-only mPDAC was 1.2y [1.1-1.5] (n = 175) compared to 2.1y [1.6-3.4] for lung-only disease (n = 32) (P = .01863, HR = 1.84 [1.11-3.06]). PDAC tumors with liver-only metastases were modestly enriched (unadjustable P < .05) for: TP53 mutations, MYC amplifications, inactivating CDK2NA alterations, inactivating SMAD alterations, and SWI/SWF pathway mutations. PDAC tumors with lung-only metastases were enriched for: STK11 mutations, CCND1 amplifications, and GNAS alterations.

CONCLUSION

Patients with lung-only mPDAC demonstrate an improved prognosis relative to those with liver-only mPDAC. Responses to chemotherapy do not explain these differences. Organotropic metastatic tumor diversity is mirrored at the molecular level in PDAC.

Contract to kill: GNAS mutation

The mutation in Gsα-coding GNAS exons, popular as gsp oncogene, is the most frequent mutation across all heterotrimeric G proteins involved in oncogenesis. GNAS R201, the most frequently mutated, followed by Q227, are found predominantly across various neoplasms and cancers such as IPMN, pituitary, thyroid, appendiceal, colorectal, etc. This review emphasizes the pivotal significance of the gsp oncogene and its ramifications underpinning the sustained addiction to GNAS mutation. Recent studies delineating the mechanistic intricacies that provide solid evidence of the profound impact of oncogenic GNAS on tumor formation, progression, and maintenance are highlighted. We have leveraged the discoveries of Gsα as an ideal neoantigen candidate for vaccine therapy, allele-specific inhibitors, and cyclic peptide-based small molecular inhibitors for G proteins and explored the therapeutic potential to target oncogenic GNAS directly. Alternative therapeutic modalities and patient-centric studies to mitigate the impact of GNAS mutations are also discussed. The exposition of novel studies and strategies designed to address the potential challenges inherent in these approaches of targeting the activating mutations of GNAS, along with probable avenues for further investigation, are highlighted. This review aims to reverberate the current understanding of the oncogenic potential of GNAS, the genomic and biological landscape of GNAS-driven neoplasms and cancers, and potential therapeutic strategies against them.

Whole-exome Sequence Analysis of Gastric-type Adenocarcinoma of the Uterine Cervix and Adjacent Lobular Endocervical Glandular Hyperplasia in the Same Case

Lobular endocervical glandular hyperplasia (LEGH) may be a precursor lesion of gastric-type adenocarcinoma of the uterine cervix (GAS). However, the genetic mechanisms underlying its carcinogenesis remain unclear. To elucidate the oncogenic process from LEGH to GAS, we compared gene mutations in early-stage GAS and adjacent LEGH in the same case. Fresh-frozen tissue sections were obtained from a patient with Stage IB3 GAS and adjacent LEGH who had undergone hysterectomy. Using laser microdissection, we harvested the LEGH and GAS portions separately from these sections and extracted the genomic DNA. Somatic variant analysis using whole-exome sequencing used DNA from the normal myometrium as a reference sequence. Somatic variants involving amino acid substitutions were detected in 61 and 125 locations in LEGH and GAS, respectively. Seven variants were common in both lesions, of which the pathogenic variant was GNAS only (c.2531G>A, p.R844H), a mutation frequently reported in pancreatic and colorectal cancers. LEGH had no other pathogenic variants; another pathogenic variant in GAS was found only at the same amino acid site as GNAS (c.2530C>T, p.R844C). In the present case, LEGH and GAS shared the same pathogenic variant of GNAS , indicating that both lesions had a common origin. Furthermore, the current results showed that the second GNAS variant is associated with the progression of LEGH to GAS. Further studies are required to elucidate GAS's pathogenesis and biological characteristics.

Endocrine dysregulation in COVID-19: molecular mechanisms and insights

This review describes the impact of COVID-19 on the endocrine system, focusing on cortisol signaling and growth factor-induced endocrine resistance. As expected, SARS-CoV-2 infection induces systemic inflammation, resulting in stimulation of the adrenal glands leading to elevated cortisol levels with normal adrenocorticotropic hormone (ACTH) levels. The cytokine storm could also stimulate cortisol production. However, in some instances, cortisol levels rise independently of ACTH due to a phenomenon known as "pseudo-Cushing's syndrome," where adrenal glands become less responsive to ACTH. Plasma proteomic analyses showed that this pattern was variably observed among COVID-19 patients, potentially involving calcium dysregulation and GNAS-regulated activities, ultimately impacting the regulation of microvascular permeability. COVID-19 also exhibited a syndrome resembling endocrine resistance, governed by receptor tyrosine kinase signaling pathways. Mild cases displayed elevated activity of EGFR and MMP9, along with increased expression of survival factors like Bax and Bcl2. In contrast, more severe cases involved IGFR-I and enhanced NOTCH signaling, with altered expression of Bcl2, AKT1, and MAPK8. In summary, these findings describe the complex interplay between COVID-19 and endocrine pathology, particularly endocrine resistance. These insights suggest potential endocrine targets for therapeutic interventions to improve short- and long-term outcomes for COVID-19 patients.

Methylation alterations of imprinted genes in different placental diseases

BACKGROUND

Imprinted genes play important functions in placentation and pregnancy; however, research on their roles in different placental diseases is limited. It is believed that epigenetic alterations, such as DNA methylation, of placental imprinting genes may contribute to the different pathological features of severe placental diseases, such as pre-eclampsia (PE) and placenta accreta spectrum disorders (PAS).

RESULTS

In this study, we conducted a comparative analysis of the methylation and expression of placental imprinted genes between PE and PAS using bisulfite sequencing polymerase chain reaction (PCR) and quantitative PCR, respectively. Additionally, we assessed oxidative damage of placental DNA by determining 8-hydroxy-2'-deoxyguanosine levels and fetal growth by determining insulin-like growth factor 2 (IGF2) and cortisol levels in the umbilical cord blood using enzyme-linked immunosorbent assay. Our results indicated that methylation and expression of potassium voltage-gated channel subfamily Q member 1, GNAS complex locus, mesoderm specific transcript, and IGF2 were significantly altered in both PE and PAS placentas. Additionally, our results revealed that the maternal imprinted genes were significantly over-expressed in PE and significantly under-expressed in PAS compared with a normal pregnancy. Moreover, DNA oxidative damage was elevated and positively correlated with IGF2 DNA methylation in both PE and PAS placentas, and cortisol and IGF2 levels were significantly decreased in PE and PAS.

CONCLUSIONS

This study suggested that DNA methylation and expression of imprinted genes are aberrant in both PE and PAS placentas and that PE and PAS have different methylation profiles, which may be linked to their unique pathogenesis.

Generation of Comprehensive GPCR-Transducer-Deficient Cell Lines to Dissect the Complexity of GPCR Signaling

G-protein-coupled receptors (GPCRs) compose the largest family of transmembrane receptors and are targets of approximately one-third of Food and Drug Administration-approved drugs owing to their involvement in almost all physiologic processes. GPCR signaling occurs through the activation of heterotrimeric G-protein complexes and β-arrestins, both of which serve as transducers, resulting in distinct cellular responses. Despite seeming simple at first glance, accumulating evidence indicates that activation of either transducer is not a straightforward process as a stimulation of a single molecule has the potential to activate multiple signaling branches. The complexity of GPCR signaling arises from the aspects of G-protein-coupling selectivity, biased signaling, interpathway crosstalk, and variable molecular modifications generating these diverse signaling patterns. Numerous questions relative to these aspects of signaling remained unanswered until the recent development of CRISPR genome-editing technology. Such genome editing technology presents opportunities to chronically eliminate the expression of G-protein subunits, β-arrestins, G-protein-coupled receptor kinases (GRKs), and many other signaling nodes in the GPCR pathways at one's convenience. Here, we review the practicality of using CRISPR-derived knockout (KO) cells in the experimental contexts of unraveling the molecular details of GPCR signaling mechanisms. To mention a few, KO cells have revealed the contribution of β-arrestins in ERK activation, Gα protein selectivity, GRK-based regulation of GPCRs, and many more, hence validating its broad applicability in GPCR studies. SIGNIFICANCE STATEMENT: This review emphasizes the practical application of G-protein-coupled receptor (GPCR) transducer knockout (KO) cells in dissecting the intricate regulatory mechanisms of the GPCR signaling network. Currently available cell lines, along with accumulating KO cell lines in diverse cell types, offer valuable resources for systematically elucidating GPCR signaling regulation. Given the association of GPCR signaling with numerous diseases, uncovering the system-based signaling map is crucial for advancing the development of novel drugs targeting specific diseases.

GNAS mutation inhibits growth and induces phosphodiesterase 4D expression in colorectal cancer cell lines

Approximately 5% of colorectal cancers (CRCs) have a gain-of-function mutation in the GNAS gene, which leads to the activation of cAMP-dependent signaling pathways and associates with poor prognosis. We investigated the effect of an activating GNAS mutation in CRC cell lines on gene expression and cell proliferation in vitro, and tumor growth in vivo. GNAS-mutated (GNASmt) HCT116 cells showed stimulated synthesis of cAMP as compared to parental (Par) cells. The most upregulated gene in the GNASmt cells was cAMP-hydrolyzing phosphodiesterase 4D (PDE4D) as detected by RNA sequencing. To further validate our finding, we analyzed PDE4D expression in a set of human CRC tumors (n = 35) and demonstrated overexpression in GNAS mutant CRC tumors as compared to GNAS wild-type tumors. The GNASmt HCT116 cells proliferated more slowly than the Par cells. PDE4 inhibitor Ro 20-1724 and PDE4D subtype selective inhibitor GEBR-7b further suppressed the proliferation of GNASmt cells without an effect on Par cells. The growth inhibitory effect of these inhibitors was also seen in the intrinsically GNAS-mutated SK-CO-1 CRC cell line having high levels of cAMP synthesis and PDE4D expression. In vivo, GNASmt HCT116 cells formed smaller tumors than the Par cells in nude mice. In conclusion, our findings demonstrate that GNAS mutation results in the growth suppression of CRC cells. Moreover, the GNAS mutation-induced overexpression of PDE4D provides a potential avenue to impede the proliferation of CRC cells through the use of PDE4 inhibitors.

Genome-Wide Analysis of DNA Methylation in Pseudomyxoma Peritonei Originated from Appendiceal Neoplasms

INTRODUCTION

Pseudomyxoma peritonei (PMP) is a disease characterized by progressive accumulation of intraperitoneal mucinous ascites produced by neoplasms in the abdominal cavity. Since the prognosis of patients with PMP remains unsatisfactory, the development of effective therapeutic drug(s) is a matter of pressing concern. Genetic analyses of PMP have clarified the frequent activation of GNAS and/or KRAS. However, the involvement of global epigenetic alterations in PMPs has not been reported.

METHODS

To clarify the genetic background of the 15 PMP tumors, we performed genetic analysis using AmpliSeq Cancer HotSpot Panel v2. We further investigated global DNA methylation in the 15 tumors and eight noncancerous colonic epithelial tissues using MethylationEPIC array BeadChip (Infinium 850k) containing a total of 865,918 probes.

RESULTS

This is the first report of comprehensive DNA methylation profiles of PMPs in the world. We clarified that the 15 PMPs could be classified into at least two epigenotypes, unique methylation epigenotype (UME) and normal-like methylation epigenotype (NLME), and that genes associated with neuronal development and synaptic signaling may be involved in the development of PMPs. In addition, we identified a set of hypermethylation marker genes such as HOXD1 and TSPYL5 in the 15 PMPs.

CONCLUSIONS

These findings may help the understanding of the molecular mechanism(s) of PMP and contribute to the development of therapeutic strategies for this life-threatening disease.

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.

Urinary insulin signaling pathway related proteins may serve as potential biomarkers for monitoring diabetes mellitus without hypertension and hyperlipidemia

The insulin signaling pathway plays an important role in the development of diabetes mellitus. The expression of insulin signaling pathway related proteins in the urine of diabetic patients has not been reported. The aim of this study was to analyze and verify the expression of insulin signaling pathway related proteins in the urine of diabetic patients without hypertension and hyperlipidemia, and to explore their clinical application value. Based on data-independent acquisition proteomics technology and bioinformatics, the urinary protein expression profile of diabetic patients without hypertension and hyperlipidemia was established. Western blot and enzyme-linked immunoassay were performed to verify the expression of insulin signaling pathway related proteins in the urine of diabetic patients. Sixteen proteins related to the insulin signaling pathway were screened in urine, and 7 of them were differentially expressed in the urine of diabetic patients without hypertension and hyperlipidemia. Further quantitative analysis showed that the downregulation of protein kinase CAMP-dependent type II regulatory subunit α, growth factor receptor bound protein 2, and guanine nucleotide-binding protein G(s) in the urine of diabetic patients without hyperlipidemia and hypertension was consistent with the preliminary screening results. In this exploratory study, we detected the expression of insulin signaling pathway related proteins in the urine of diabetic patients without hypertension and hyperlipidemia. protein kinase CAMP-dependent type II regulatory subunit α, growth factor receptor bound protein 2, and guanine nucleotide-binding protein G(s) in the urine of diabetic patients were downregulated, which was associated with diabetes. They may be promising noninvasive biomarkers for monitoring diabetes.