Somatic activation of the K-ras oncogene causes early onset lung cancer in mice

NEMO/NF-κB signaling functions as a double-edged sword in PanIN formation versus progression to pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is marked by a dismal survival rate, lacking effective therapeutics due to its aggressive growth, late-stage diagnosis, and chemotherapy resistance. Despite debates on NF-κB targeting for PDAC treatment, no successful approach has emerged.

METHODS

To elucidate the role of NF-κB, we ablated NF-κB essential modulator (NEMO), critical for conventional NF-κB signaling, in the pancreata of mice that develop precancerous lesions (KC mouse model). Secretagogue-induced pancreatitis by cerulein injections was utilized to promote inflammation and accelerate PDAC development.

RESULTS

NEMO deletion reduced fibrosis and inflammation in young KC mice, resulting in fewer pancreatic intraepithelial neoplasias (PanINs) at later stages. Paradoxically, however, NEMO deletion accelerated the progression of these fewer PanINs to PDAC and reduced median lifespan. Further, analysis of tissue microarrays from human PDAC sections highlighted the correlation between reduced NEMO expression in neoplastic cells and poorer prognosis, supporting our observation in mice. Mechanistically, NEMO deletion impeded oncogene-induced senescence (OIS), which is normally active in low-grade PanINs. This blockage resulted in fewer senescence-associated secretory phenotype (SASP) factors, reducing inflammation. However, blocked OIS fostered replication stress and DNA damage accumulation which accelerated PanIN progression to PDAC. Finally, treatment with the DNA damage-inducing reagent etoposide resulted in elevated cell death in NEMO-ablated PDAC cells compared to their NEMO-competent counterparts, indicative of a synthetic lethality paradigm.

CONCLUSIONS

NEMO exhibited both oncogenic and tumor-suppressive properties during PDAC development. Caution is suggested in therapeutic interventions targeting NF-κB, which may be detrimental during PanIN progression but beneficial post-PDAC development.

How CRISPR Is Revolutionizing the Generation of New Models for Cancer Research

Cancers arise through acquisition of mutations in genes that regulate core biological processes like cell proliferation and cell death. Decades of cancer research have led to the identification of genes and mutations causally involved in disease development and evolution, yet defining their precise function across different cancer types and how they influence therapy responses has been challenging. Mouse models have helped define the in vivo function of cancer-associated alterations, and genome-editing approaches using CRISPR have dramatically accelerated the pace at which these models are developed and studied. Here, we highlight how CRISPR technologies have impacted the development and use of mouse models for cancer research and discuss the many ways in which these rapidly evolving platforms will continue to transform our understanding of this disease.

Simulated galactic cosmic radiation-induced cancer progression in mice

Prolonged manned space flight exposure risks to galactic comic radiation, has led to uncertainties in a variety of health risks. Our previous work, utilizing either single ion or multiple ion radiation exposure conducted at the NSRL (NASA Space Radiation Laboratory, Brookhaven, NY) demonstrated that HZE ion components of the GCR result in persistent inflammatory signaling, increased mutations, and higher rates of cancer initiation and progression. With the development of the 33-beam galactic cosmic radiation simulations (GCRsim) at the NSRL, we can more closely test on earth the radiation environment found in space. With a previously used lung cancer susceptible mouse model (K-rasLA-1), we performed acute exposure experiments lasting 1-2 h, and chronic exposure experiments lasting 2-6 weeks with a total dose of 50 cGy and 75 cGy. We obtained histological samples from a subset of mice 100 days post-irradiation, and the remaining mice were monitored for overall survival up to 1-year post-irradiation. When we compared acute exposures (1-2 hrs.) and chronic exposure (2-6 weeks), we found a trend in the increase of lung adenocarcinoma respectively for a total dose of 50 cGy and 75 cGy. Furthermore, when we added neutron exposure to the 75 cGy of GCRsim, we saw a further increase in the incidence of adenocarcinoma. We interpret these findings to suggest that the risks of carcinogenesis are heightened with doses anticipated during a round trip to Mars, and this risk is magnified when coupled with extra neutron exposure that are expected on the Martian surface. We also observed that risks are reduced when the NASA official 33-beam GCR simulations are provided at high dose rates compared to low dose rates.

Nicotinamide in Combination with EGFR-TKIs for the Treatment of Stage IV Lung Adenocarcinoma with EGFR Mutations: A Randomized Double-Blind (Phase IIb) Trial

PURPOSE

RUNX3 is a tumor suppressor gene, which is inactivated in approximately 70% of lung adenocarcinomas. Nicotinamide, a sirtuin inhibitor, has demonstrated potential in re-activating epigenetically silenced RUNX3 in cancer cells. This study assessed the therapeutic benefits of combining nicotinamide with first-generation EGFR-tyrosine kinase inhibitors (TKI) for patients with stage IV lung cancer carrying EGFR mutations.

PATIENTS AND METHODS

We assessed the impact of nicotinamide on carcinogen-induced lung adenocarcinomas in mice and observed that nicotinamide increased RUNX3 levels and inhibited lung cancer growth. Subsequently, 110 consecutive patients with stage IV lung cancer who had EGFR mutations were recruited: 70 females (63.6%) and 84 never-smokers (76.4%). The patients were randomly assigned to receive either nicotinamide (1 g/day, n = 55) or placebo (n = 55). The primary and secondary endpoints were progression-free survival (PFS) and overall survival (OS), respectively.

RESULTS

After a median follow-up of 54.3 months, the nicotinamide group exhibited a median PFS of 12.7 months [95% confidence interval (CI), 10.4-18.3], while the placebo group had a PFS of 10.9 months (9.0-13.2; P = 0.2). The median OS was similar in the two groups (31.0 months with nicotinamide vs. 29.4 months with placebo; P = 0.2). Notably, subgroup analyses revealed a significant reduction in mortality risk for females (P = 0.01) and never-smokers (P = 0.03) treated with nicotinamide.

CONCLUSIONS

The addition of nicotinamide with EGFR-TKIs demonstrated potential improvements in PFS and OS, with notable survival benefits for female patients and those who had never smoked (ClinicalTrials.gov Identifier: NCT02416739).

Emerging In Vitro and In Vivo Models: Hope for the Better Understanding of Cancer Progression and Treatment

Various cancer models have been developed to aid the understanding of the underlying mechanisms of tumor development and evaluate the effectiveness of various anticancer drugs in preclinical studies. These models accurately reproduce the critical stages of tumor initiation and development to mimic the tumor microenvironment better. Using these models for target validation, tumor response evaluation, resistance modeling, and toxicity comprehension can significantly enhance the drug development process. Herein, various in vivo or animal models are presented, typically consisting of several mice and in vitro models ranging in complexity from transwell models to spheroids and CRISPR-Cas9 technologies. While in vitro models have been used for decades and dominate the early stages of drug development, they are still limited primary to simplistic tests based on testing on a single cell type cultivated in Petri dishes. Recent advancements in developing new cancer therapies necessitate the generation of complicated animal models that accurately mimic the tumor's complexity and microenvironment. Mice make effective tumor models as they are affordable, have a short reproductive cycle, exhibit rapid tumor growth, and are simple to manipulate genetically. Human cancer mouse models are crucial to understanding the neoplastic process and basic and clinical research improvements. The following review summarizes different in vitro and in vivo metastasis models, their advantages and disadvantages, and their ability to serve as a model for cancer research.

Beyond genetics: driving cancer with the tumour microenvironment behind the wheel

Cancer has long been viewed as a genetic disease of cumulative mutations. This notion is fuelled by studies showing that ageing tissues are often riddled with clones of complex oncogenic backgrounds coexisting in seeming harmony with their normal tissue counterparts. Equally puzzling, however, is how cancer cells harbouring high mutational burden contribute to normal, tumour-free mice when allowed to develop within the confines of healthy embryos. Conversely, recent evidence suggests that adult tissue cells expressing only one or a few oncogenes can, in some contexts, generate tumours exhibiting many of the features of a malignant, invasive cancer. These disparate observations are difficult to reconcile without invoking environmental cues triggering epigenetic changes that can either dampen or drive malignant transformation. In this Review, we focus on how certain oncogenes can launch a two-way dialogue of miscommunication between a stem cell and its environment that can rewire downstream events non-genetically and skew the morphogenetic course of the tissue. We review the cells and molecules of and the physical forces acting in the resulting tumour microenvironments that can profoundly affect the behaviours of transformed cells. Finally, we discuss possible explanations for the remarkable diversity in the relative importance of mutational burden versus tumour microenvironment and its clinical relevance.

Spontaneous expression of the CIC::DUX4 fusion oncoprotein from a conditional allele potently drives sarcoma formation in genetically engineered mice

CIC::DUX4 sarcoma (CDS) is a rare but highly aggressive undifferentiated small round cell sarcoma driven by a fusion between the tumor suppressor Capicua (CIC) and DUX4. Currently, there are no effective treatments and efforts to identify and translate better therapies are limited by the scarcity of patient tumor samples and cell lines. To address this limitation, we generated three genetically engineered mouse models of CDS (Ch7CDS, Ai9CDS, and TOPCDS). Remarkably, chimeric mice from all three conditional models developed spontaneous soft tissue tumors and disseminated disease in the absence of Cre-recombinase. The penetrance of spontaneous (Cre-independent) tumor formation was complete irrespective of bi-allelic Cic function and the distance between adjacent loxP sites. Characterization of soft tissue and presumed metastatic tumors showed that they consistently expressed the CIC::DUX4 fusion protein and many downstream markers of the disease credentialing the models as CDS. In addition, tumor-derived cell lines were generated and ChIP-seq was preformed to map fusion-gene specific binding using an N-terminal HA epitope tag. These datasets, along with paired H3K27ac ChIP-sequencing maps, validate CIC::DUX4 as a neomorphic transcriptional activator. Moreover, they are consistent with a model where ETS family transcription factors are cooperative and redundant drivers of the core regulatory circuitry in CDS.

SOX17 enables immune evasion of early colorectal adenomas and cancers

A hallmark of cancer is the avoidance of immune destruction. This process has been primarily investigated in locally advanced or metastatic cancer1-3; however, much less is known about how pre-malignant or early invasive tumours evade immune detection. Here, to understand this process in early colorectal cancers (CRCs), we investigated how naive colon cancer organoids that were engineered in vitro to harbour Apc-null, KrasG12D and Trp53-null (AKP) mutations adapted to the in vivo native colonic environment. Comprehensive transcriptomic and chromatin analyses revealed that the endoderm-specifying transcription factor SOX17 became strongly upregulated in vivo. Notably, whereas SOX17 loss did not affect AKP organoid propagation in vitro, its loss markedly reduced the ability of AKP tumours to persist in vivo. The small fraction of SOX17-null tumours that grew displayed notable interferon-γ (IFNγ)-producing effector-like CD8+ T cell infiltrates in contrast to the immune-suppressive microenvironment in wild-type counterparts. Mechanistically, in both endogenous Apc-null pre-malignant adenomas and transplanted organoid-derived AKP CRCs, SOX17 suppresses the ability of tumour cells to sense and respond to IFNγ, preventing anti-tumour T cell responses. Finally, SOX17 engages a fetal intestinal programme that drives differentiation away from LGR5+ tumour cells to produce immune-evasive LGR5- tumour cells with lower expression of major histocompatibility complex class I (MHC-I). We propose that SOX17 is a transcription factor that is engaged during the early steps of colon cancer to orchestrate an immune-evasive programme that permits CRC initiation and progression.

PTEN Deficiency Induces an Extrahepatic Cholangitis-Cholangiocarcinoma Continuum via Aurora kinase A in Mice

BACKGROUND & AIMS

The PTEN-AKT pathway is frequently altered in extrahepatic cholangiocarcinoma (eCCA). We aim to evaluate the role of PTEN in the pathogenesis of eCCA and find novel therapies for this disease.

METHODS

The Pten gene in the biliary epithelial cells were genetically deleted using the Cre-loxp system. The pathologies were evaluated both macroscopically and histologically. The characteristics were further analyzed by immunohistochemistry (IHC), RT-PCR, cell culture, and RNAseq. Some features were compared to those in human eCCA samples. Further mechanistic studies utilized the conditional knockout of Trp53 and Aurora kinase A (Aurka) genes. Experimental therapy was tested using an Aurka inhibitor.

RESULTS

We observed that genetic deletion of the Pten gene in the extrahepatic biliary epithelium and peri-ductal glands initiated sclerosing cholangitis-like lesions in mice, resulting in enlarged and distorted extrahepatic bile ducts in mice as early as one month old. Histologically, these lesions exhibited increased epithelial proliferation, inflammatory cell infiltration, and fibrosis. With aging, the lesions progressed from low-grade dysplasia to invasive carcinoma. Trp53 inactivation further accelerated the disease progression, potentially through downregulating senescence. Further mechanistic studies showed that both human and mouse eCCA showed high expressions of AURKA. Notably, the genetic deletion of Aurka completely eliminated Pten deficiency-induced extrahepatic bile duct lesions. Furthermore, pharmacological inhibition of Aurka alleviated disease progression.

CONCLUSIONS

Pten deficiency in extrahepatic cholangiocytes and peribiliary glands led to a cholangitis-to-cholangiocarcinoma continuum through an Aurka-dependent manner. These findings offer new insights into preventive and therapeutic interventions for extrahepatic CCA.

IMPACT AND IMPLICATIONS

The aberrant PTEN-PI3K-AKT signaling pathway is commonly observed in human extrahepatic cholangiocarcinoma (eCCA), a disease with a poor prognosis. In our study, we developed a mouse model mimicking cholangitis to eCCA progression by conditionally deleting the Pten gene via Pdx1-Cre in epithelial cells and peribiliary glands of the extrahepatic biliary duct. The conditional Pten deletion in these cells led to cholangitis, which gradually advanced to dysplasia, ultimately resulting in eCCA. The loss of Pten heightened Akt signaling, cell proliferation, inflammation, fibrosis, DNA damage, epigenetic signaling, epithelial-mesenchymal transition (EMT), cell dysplasia, and cellular senescence. Genetic deletion or pharmacological inhibition of Aurka successfully halted the disease progression. This model shall be valuable for testing novel therapies and unraveling the mechanisms of eCCA tumorigenesis.

Oncoprotein SET-associated transcription factor ZBTB11 triggers lung cancer metastasis

Metastasis is the major cause of lung cancer-related death, but the mechanisms governing lung tumor metastasis remain incompletely elucidated. SE translocation (SET) is overexpressed in lung tumors and correlates with unfavorable prognosis. Here we uncover SET-associated transcription factor, zinc finger and BTB domain-containing protein 11 (ZBTB11), as a prometastatic regulator in lung tumors. SET interacts and collaborates with ZBTB11 to promote lung cancer cell migration and invasion, primarily through SET-ZBTB11 complex-mediated transcriptional activation of matrix metalloproteinase-9 (MMP9). Additionally, by transcriptional repression of proline-rich Gla protein 2 (PRRG2), ZBTB11 links Yes-associated protein 1 (YAP1) activation to drive lung tumor metastasis independently of SET-ZBTB11 complex. Loss of ZBTB11 suppresses distal metastasis in a lung tumor mouse model. Overexpression of ZBTB11 is recapitulated in human metastatic lung tumors and correlates with diminished survival. Our study demonstrates ZBTB11 as a key metastatic regulator and reveals diverse mechanisms by which ZBTB11 modulates lung tumor metastasis.

Applying deep learning to segmentation of murine lung tumors in pre-clinical micro-computed tomography

Lung cancer remains a leading cause of cancer-related death, but scientists have made great strides in developing new treatments recently, partly owing to the use of genetically engineered mouse models (GEMMs). GEMM tumors represent a translational model that recapitulates human disease better than implanted models because tumors develop spontaneously in the lungs. However, detection of these tumors relies on in vivo imaging tools, specifically micro-Computed Tomography (micro-CT or µCT), and image analysis can be laborious with high inter-user variability. Here we present a deep learning model trained to perform fully automated segmentation of lung tumors without the interference of other soft tissues. Trained and tested on 100 3D µCT images (18,662 slices) that were manually segmented, the model demonstrated a high correlation to manual segmentations on the testing data (r2=0.99, DSC=0.78) and on an independent dataset (n = 12 3D scans or 2328 2D slices, r2=0.97, DSC=0.73). In a comparison against manual segmentation performed by multiple analysts, the model (r2=0.98, DSC=0.78) performed within inter-reader variability (r2=0.79, DSC=0.69) and close to intra-reader variability (r2=0.99, DSC=0.82), all while completing 5+ hours of manual segmentations in 1 minute. Finally, when applied to a real-world longitudinal study (n = 55 mice), the model successfully detected tumor progression over time and the differences in tumor burden between groups induced with different virus titers, aligning well with more traditional analysis methods. In conclusion, we have developed a deep learning model which can perform fast, accurate, and fully automated segmentation of µCT scans of murine lung tumors.

Preclinical Modeling of Pathway-Targeted Therapy of Human Lung Cancer in the Mouse

Animal models, particularly genetically engineered mouse models (GEMMs), continue to have a transformative impact on our understanding of the initiation and progression of hematological malignancies and solid tumors. Furthermore, GEMMs have been employed in the design and optimization of potent anticancer therapies. Increasingly, drug responses are assessed in mouse models either prior, or in parallel, to the implementation of precision medical oncology, in which groups of patients with genetically stratified cancers are treated with drugs that target the relevant oncoprotein such that mechanisms of drug sensitivity or resistance may be identified. Subsequently, this has led to the design and preclinical testing of combination therapies designed to forestall the onset of drug resistance. Indeed, mouse models of human lung cancer represent a paradigm for how a wide variety of GEMMs, driven by a variety of oncogenic drivers, have been generated to study initiation, progression, and maintenance of this disease as well as response to drugs. These studies have now expanded beyond targeted therapy to include immunotherapy. We highlight key aspects of the relationship between mouse models and the evolution of therapeutic approaches, including oncogene-targeted therapies, immunotherapies, acquired drug resistance, and ways in which successful antitumor strategies improve on efficiently translating preclinical approaches into successful antitumor strategies in patients.

The Abundance of KRAS and RAS Gene Mutations in Cancer

Mutant forms of the RAS genes KRAS, NRAS, and HRAS are important and common drivers of cancer. Recently, two independent teams that integrated cancer genomics with cancer epidemiology estimated that approximately 15-20% of all human cancers harbor a mutation in one of these three RAS genes. These groups also estimate KRAS mutations occur in 11-14% of all human cancers. Although these estimates are lower than many commonly encountered values, these estimates continue to rank KRAS and the ensemble of RAS oncogenes among the most common genetic drivers of cancer across all forms of malignancy.

Harnessing G-quadruplex ligands for lung cancer treatment: A comprehensive overview

Lung cancer (LC) remains a leading cause of mortality worldwide, and new therapeutic strategies are urgently needed. One such approach revolves around the utilization of four-stranded nucleic acid secondary structures, known as G-quadruplexes (G4), which are formed by G-rich sequences. Ligands that bind selectively to G4 structures present a promising strategy for regulating crucial cellular processes involved in the progression of LC, rendering them potent agents for lung cancer treatment. In this review, we offer a summary of recent advancements in the development of G4 ligands capable of targeting specific genes associated with the development and progression of lung cancer.

Runx3 Restoration Regresses K-Ras-Activated Mouse Lung Cancers and Inhibits Recurrence

Oncogenic K-RAS mutations occur in approximately 25% of human lung cancers and are most frequently found in codon 12 (G12C, G12V, and G12D). Mutated K-RAS inhibitors have shown beneficial results in many patients; however, the inhibitors specifically target K-RASG12C and acquired resistance is a common occurrence. Therefore, new treatments targeting all kinds of oncogenic K-RAS mutations with a durable response are needed. RUNX3 acts as a pioneer factor of the restriction (R)-point, which is critical for the life and death of cells. RUNX3 is inactivated in most K-RAS-activated mouse and human lung cancers. Deletion of mouse lung Runx3 induces adenomas (ADs) and facilitates the development of K-Ras-activated adenocarcinomas (ADCs). In this study, conditional restoration of Runx3 in an established K-Ras-activated mouse lung cancer model regressed both ADs and ADCs and suppressed cancer recurrence, markedly increasing mouse survival. Runx3 restoration suppressed K-Ras-activated lung cancer mainly through Arf-p53 pathway-mediated apoptosis and partly through p53-independent inhibition of proliferation. This study provides in vivo evidence supporting RUNX3 as a therapeutic tool for the treatment of K-RAS-activated lung cancers with a durable response.

Acid-base homeostasis orchestrated by NHE1 defines the pancreatic stellate cell phenotype in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) progresses in an organ with a unique pH landscape, where the stroma acidifies after each meal. We hypothesized that disrupting this pH landscape during PDAC progression triggers pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) to induce PDAC fibrosis. We revealed that alkaline environmental pH was sufficient to induce PSC differentiation to a myofibroblastic phenotype. We then mechanistically dissected this finding, focusing on the involvement of the Na+/H+ exchanger NHE1. Perturbing cellular pH homeostasis by inhibiting NHE1 with cariporide partially altered the myofibroblastic PSC phenotype. To show the relevance of this finding in vivo, we targeted NHE1 in murine PDAC (KPfC). Indeed, tumor fibrosis decreased when mice received the NHE1-inhibitor cariporide in addition to gemcitabine treatment. Moreover, the tumor immune infiltrate shifted from granulocyte rich to more lymphocytic. Taken together, our study provides mechanistic evidence on how the pancreatic pH landscape shapes pancreatic cancer through tuning PSC differentiation.

Mismatch repair deficiency is not sufficient to elicit tumor immunogenicity

DNA mismatch repair deficiency (MMRd) is associated with a high tumor mutational burden (TMB) and sensitivity to immune checkpoint blockade (ICB) therapy. Nevertheless, most MMRd tumors do not durably respond to ICB and critical questions remain about immunosurveillance and TMB in these tumors. In the present study, we developed autochthonous mouse models of MMRd lung and colon cancer. Surprisingly, these models did not display increased T cell infiltration or ICB response, which we showed to be the result of substantial intratumor heterogeneity of mutations. Furthermore, we found that immunosurveillance shapes the clonal architecture but not the overall burden of neoantigens, and T cell responses against subclonal neoantigens are blunted. Finally, we showed that clonal, but not subclonal, neoantigen burden predicts ICB response in clinical trials of MMRd gastric and colorectal cancer. These results provide important context for understanding immune evasion in cancers with a high TMB and have major implications for therapies aimed at increasing TMB.

Immune Dysfunction from Radiation Exposure

The hematopoietic system is highly sensitive to ionizing radiation. Damage to the immune system may result in opportunistic infections and hemorrhage, which could lead to mortality. Inflammation triggered by tissue damage can also lead to additional local or widespread tissue damage. The immune system is responsible for tissue repair and restoration, which is made more challenging when it is in the process of self-recovery. Because of these challenges, the Radiation and Nuclear Countermeasures Program (RNCP) and the Basic Immunology Branch (BIB) under the Division of Allergy, Immunology, and Transplantation (DAIT) within the National Institute of Allergy and Infectious Diseases (NIAID), along with partners from the Biomedical Advanced Research and Development Authority (BARDA), and the Radiation Injury Treatment Network (RITN) sponsored a two-day meeting titled Immune Dysfunction from Radiation Exposure held on September 9-10, 2020. The intent was to discuss the manifestations and mechanisms of radiation-induced immune dysfunction in people and animals, identify knowledge gaps, and discuss possible treatments to restore immune function and enhance tissue repair after irradiation.

Critical requirement of SOS1 for tumor development and microenvironment modulation in KRASG12D-driven lung adenocarcinoma

The impact of genetic ablation of SOS1 or SOS2 is evaluated in a murine model of KRASG12D-driven lung adenocarcinoma (LUAD). SOS2 ablation shows some protection during early stages but only SOS1 ablation causes significant, specific long term increase of survival/lifespan of the KRASG12D mice associated to markedly reduced tumor burden and reduced populations of cancer-associated fibroblasts, macrophages and T-lymphocytes in the lung tumor microenvironment (TME). SOS1 ablation also causes specific shrinkage and regression of LUAD tumoral masses and components of the TME in pre-established KRASG12D LUAD tumors. The critical requirement of SOS1 for KRASG12D-driven LUAD is further confirmed by means of intravenous tail injection of KRASG12D tumor cells into SOS1KO/KRASWT mice, or of SOS1-less, KRASG12D tumor cells into wildtype mice. In silico analyses of human lung cancer databases support also the dominant role of SOS1 regarding tumor development and survival in LUAD patients. Our data indicate that SOS1 is critically required for development of KRASG12D-driven LUAD and confirm the validity of this RAS-GEF activator as an actionable therapeutic target in KRAS mutant LUAD.

A novel onco-cardiological mouse model of lung cancer-induced cardiac dysfunction and its application in identifying potential roles of tRNA-derived small RNAs

An increasing body of research suggests cancer-induced cardiovascular diseases, leading to the appearance of an interdisciplinary study known as onco-cardiology. Lung cancer has the highest incidence and mortality. Cardiac dysfunction constitutes a major cause of death in lung cancer patients. However, its mechanism has not been elucidated because suitable animal models that adequately mimic clinical features are lacking. Here, we established a novel chemically induced lung cancer mouse model using benzo[a]pyrene and urethane to recapitulate the general characteristics of cardiac dysfunction caused by lung cancer, the cardiac disorders in the context of the progression of lung cancer were evaluated using echocardiographic and histological approaches. The pathological changes included myocardial ischaemia, pericarditis, cardiac pre-cachexia, and pulmonary artery hypertension. We performed sequencing to detect the tRNA-derived fragments and tRNA-derived stress-induced RNAs (tRFs/tiRNAs) expressions in mouse heart tissue. 22 upregulated and 16 downregulated tRFs/tiRNAs were identified. Subsequently, the top 10 significant results of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were presented. The in vitro model was established by exposing neonatal rat cardiomyocytes and myocardial fibroblasts to lung tumour cell-conditioned medium, respectively. Western blotting revealed significant changes in cardiac failure markers (atrial natriuretic peptide and α-myosin heavy chain) and cardiac fibrosis markers (Collagen-1 and Collagen-3). Our model adequately reflects the pathological features of lung cancer-induced cardiac dysfunction. Furthermore, the altered tRF/tiRNA profiles showed great promise as novel targets for therapies. These results might pave the way for research on therapeutic targets in onco-cardiology.

Small molecular inhibitors for KRAS-mutant cancers

Three rat sarcoma (RAS) gene isoforms, KRAS, NRAS, and HRAS, constitute the most mutated family of small GTPases in cancer. While the development of targeted immunotherapies has led to a substantial improvement in the overall survival of patients with non-KRAS-mutant cancer, patients with RAS-mutant cancers have an overall poorer prognosis owing to the high aggressiveness of RAS-mutant tumors. KRAS mutations are strongly implicated in lung, pancreatic, and colorectal cancers. However, RAS mutations exhibit diverse patterns of isoforms, substitutions, and positions in different types of cancers. Despite being considered "undruggable", recent advances in the use of allele-specific covalent inhibitors against the most common mutant form of RAS in non-small-cell lung cancer have led to the development of effective pharmacological interventions against RAS-mutant cancer. Sotorasib (AMG510) has been approved by the FDA as a second-line treatment for patients with KRAS-G12C mutant NSCLC who have received at least one prior systemic therapy. Other KRAS inhibitors are on the way to block KRAS-mutant cancers. In this review, we summarize the progress and promise of small-molecule inhibitors in clinical trials, including direct inhibitors of KRAS, pan-RAS inhibitors, inhibitors of RAS effector signaling, and immune checkpoint inhibitors or combinations with RAS inhibitors, to improve the prognosis of tumors with RAS mutations.

Phosphorylated nuclear DICER1 promotes open chromatin state and lineage plasticity of AT2 tumor cells in lung adenocarcinomas

KRAS/ERK pathway phosphorylates DICER1, causing its nuclear translocation, and phosphomimetic Dicer1 contributes to tumorigenesis in mice. Mechanisms through which phospho-DICER1 regulates tumor progression remain undefined. While DICER1 canonically regulates microRNAs (miRNA) and epithelial-to-mesenchymal transition (EMT), we found that phosphorylated nuclear DICER1 (phospho-nuclear DICER1) promotes late-stage tumor progression in mice with oncogenic Kras, independent of miRNAs and EMT. Instead, we observe that the murine AT2 tumor cells exhibit altered chromatin compaction, and cells from disorganized advanced tumors, but not localized tumors, express gastric genes. Collectively, this results in subpopulations of tumor cells transitioning from a restricted alveolar to a broader endodermal lineage state. In human LUADs, we observed expression of phospho-nuclear DICER1 in advanced tumors together with the expression of gastric genes. We define a multimeric chromatin-DICER1 complex composed of the Mediator complex subunit 12, CBX1, MACROH2A.1, and transcriptional regulators supporting the model that phospho-nuclear DICER1 leads to lineage reprogramming of AT2 tumor cells to mediate lung cancer progression.

Oncogenic K-Ras suppresses global miRNA function

K-Ras frequently acquires gain-of-function mutations (K-RasG12D being the most common) that trigger significant transcriptomic and proteomic changes to drive tumorigenesis. Nevertheless, oncogenic K-Ras-induced dysregulation of post-transcriptional regulators such as microRNAs (miRNAs) during oncogenesis is poorly understood. Here, we report that K-RasG12D promotes global suppression of miRNA activity, resulting in the upregulation of hundreds of targets. We constructed a comprehensive profile of physiological miRNA targets in mouse colonic epithelium and tumors expressing K-RasG12D using Halo-enhanced Argonaute pull-down. Combining this with parallel datasets of chromatin accessibility, transcriptome, and proteome, we uncovered that K-RasG12D suppressed the expression of Csnk1a1 and Csnk2a1, subsequently decreasing Ago2 phosphorylation at Ser825/829/832/835. Hypo-phosphorylated Ago2 increased binding to mRNAs while reducing its activity to repress miRNA targets. Our findings connect a potent regulatory mechanism of global miRNA activity to K-Ras in a pathophysiological context and provide a mechanistic link between oncogenic K-Ras and the post-transcriptional upregulation of miRNA targets.

Grading of lung adenocarcinomas with simultaneous segmentation by artificial intelligence (GLASS-AI)

Preclinical genetically engineered mouse models (GEMMs) of lung adenocarcinoma are invaluable for investigating molecular drivers of tumor formation, progression, and therapeutic resistance. However, histological analysis of these GEMMs requires significant time and training to ensure accuracy and consistency. To achieve a more objective and standardized analysis, we used machine learning to create GLASS-AI, a histological image analysis tool that the broader cancer research community can utilize to grade, segment, and analyze tumors in preclinical models of lung adenocarcinoma. GLASS-AI demonstrates strong agreement with expert human raters while uncovering a significant degree of unreported intratumor heterogeneity. Integrating immunohistochemical staining with high-resolution grade analysis by GLASS-AI identified dysregulation of Mapk/Erk signaling in high-grade lung adenocarcinomas and locally advanced tumor regions. Our work demonstrates the benefit of employing GLASS-AI in preclinical lung adenocarcinoma models and the power of integrating machine learning and molecular biology techniques for studying the molecular pathways that underlie cancer progression.

The HDAC2-SP1 Axis Orchestrates Protumor Macrophage Polarization

Tumor-associated macrophages (TAM), including antitumor M1-like TAMs and protumor M2-like TAMs, are transcriptionally dynamic innate immune cells with diverse roles in lung cancer development. Epigenetic regulators are key in controlling macrophage fate in the heterogeneous tumor microenvironment. Here, we demonstrate that the spatial proximity of HDAC2-overexpressing M2-like TAMs to tumor cells significantly correlates with poor overall survival of lung cancer patients. Suppression of HDAC2 in TAMs altered macrophage phenotype, migration, and signaling pathways related to interleukins, chemokines, cytokines, and T-cell activation. In coculture systems of TAMs and cancer cells, suppressing HDAC2 in TAMs resulted in reduced proliferation and migration, increased apoptosis of cancer cell lines and primary lung cancer cells, and attenuated endothelial cell tube formation. HDAC2 regulated the M2-like TAM phenotype via acetylation of histone H3 and transcription factor SP1. Myeloid cell-specific deletion of Hdac2 and pharmacologic inhibition of class I HDACs in four different murine lung cancer models induced the switch from M2-like to M1-like TAMs, altered infiltration of CD4+ and CD8+ T cells, and reduced tumor growth and angiogenesis. TAM-specific HDAC2 expression may provide a biomarker for lung cancer stratification and a target for developing improved therapeutic approaches.

SIGNIFICANCE

HDAC2 inhibition reverses the protumor phenotype of macrophages mediated by epigenetic modulation induced by the HDAC2-SP1 axis, indicating a therapeutic option to modify the immunosuppressive tumor microenvironment.

Immunosurveillance shapes the emergence of neo-epitope landscapes of sarcomas, revealing prime targets for immunotherapy

T cells recognize tumor-derived mutated peptides presented on MHC by tumors. The recognition of these neo-epitopes leads to rejection of tumors, an event that is critical for successful cancer immunosurveillance. Determination of tumor-rejecting neo-epitopes in human tumors has proved difficult, though recently developed systems approaches are becoming increasingly useful at evaluating their immunogenicity. We have used the differential aggretope index to determine the neo-epitope burden of sarcomas and observed a conspicuously titrated antigenic landscape, ranging from the highly antigenic osteosarcomas to the low antigenic leiomyosarcomas and liposarcomas. We showed that the antigenic landscape of the tumors inversely reflected the historical T cell responses in the tumor-bearing patients. We predicted that highly antigenic tumors with poor antitumor T cell responses, such as osteosarcomas, would be responsive to T cell-based immunotherapy regimens and demonstrated this in a murine osteosarcoma model. Our study presents a potentially novel pipeline for determining antigenicity of human tumors, provides an accurate predictor of potential neo-epitopes, and will be an important indicator of which cancers to target with T cell-enhancing immunotherapy.

Senescent alveolar macrophages promote early-stage lung tumorigenesis

Senescent cells play relevant but context-dependent roles during tumorigenesis. Here, in an oncogenic Kras-driven lung cancer mouse model, we found that senescent cells, specifically alveolar macrophages, accumulate early in neoplasia. These macrophages have upregulated expression of p16INK4a and Cxcr1, are distinct from previously defined subsets and are sensitive to senolytic interventions, and suppress cytotoxic T cell responses. Their removal attenuates adenoma development and progression in mice, indicating their tumorigenesis-promoting role. Importantly, we found that alveolar macrophages with these properties increase with normal aging in mouse lung and in human lung adenocarcinoma in situ. Collectively, our study indicates that a subset of tissue-resident macrophages can support neoplastic transformation through altering their local microenvironment, suggesting that therapeutic interventions targeting senescent macrophages may attenuate lung cancer progression during early stages of disease.

Early-Life Exposure to Lipopolysaccharide Induces Persistent Changes in Gene Expression Profiles in the Liver and Spleen of Female FVB/N Mice

The objective of this study was to investigate how subcutaneous (sc) lipopolysaccharide (LPS) administration affects the gene expression profiles of insulin signaling as well as innate and adaptive immunity genes in mouse livers and spleens. FVB/N female mice were randomly assigned to one of two treatment groups at 5 weeks of age: (1) a six-week subcutaneous injection of saline at 11 μL/h (control-CON), or (2) a six-week subcutaneous injection of LPS from Escherichia coli 0111:B4 at 0.1 μg/g body weight at 11 μL/h. At 106 weeks (i.e., 742 days) after the last treatment, mice were euthanized. Following euthanasia, liver and spleen samples were collected, snap frozen, and stored at -80 °C until gene expression profiling. LPS upregulated nine genes in the liver, according to the findings (Pparg, Frs3, Kras, Raf1, Gsk3b, Rras2, Hk2, Pik3r2, and Myd88). With a 4.18-fold increase over the CON group, Pparg was the most up-regulated gene in the liver. Based on the annotation cluster analysis, LPS treatment upregulated liver genes which are involved in pathways associated with hepatic steatosis, B- and T-cell receptor signaling, chemokine signaling, as well as other types of cancers such as endometrial cancer, prostate cancer, and colorectal cancer. LPS increased the spleen expression of Ccl11, Ccl25, Il6, Cxcl5, Pparg, Tlr4, Nos2, Cxcl11, Il1a, Ccl17, and Fcgr3, all of which are involved in innate and adaptive immune responses and the regulation of cytokine production. Furthermore, functional analysis revealed that cytokine-cytokine receptor interaction and chemokine signaling pathways were the most enriched in LPS-treated mice spleen tissue. Our findings support the notion that early-life LPS exposure can result in long-term changes in gene expression profiling in the liver and spleen tissues of FVB/N female mice.

p53 governs an AT1 differentiation programme in lung cancer suppression

Lung cancer is the leading cause of cancer deaths worldwide1. Mutations in the tumour suppressor gene TP53 occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis1-4, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, specifically by promoting alveolar type 1 (AT1) differentiation. Using mice that express oncogenic Kras and null, wild-type or hypermorphic Trp53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA sequencing and ATAC sequencing of LUAD cells uncovered a p53-induced AT1 differentiation programme during tumour suppression in vivo through direct DNA binding, chromatin remodelling and induction of genes characteristic of AT1 cells. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 cell differentiation in alveolar injury repair. Notably, p53 inactivation results in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signalling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of Trp53 wild-type and Trp53-null mice showed that p53 also directs alveolar regeneration after injury by regulating AT2 cell self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumour suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.

Lymphocyte networks are dynamic cellular communities in the immunoregulatory landscape of lung adenocarcinoma

Lymphocytes are key for immune surveillance of tumors, but our understanding of the spatial organization and physical interactions that facilitate lymphocyte anti-cancer functions is limited. We used multiplexed imaging, quantitative spatial analysis, and machine learning to create high-definition maps of lung tumors from a Kras/Trp53-mutant mouse model and human resections. Networks of interacting lymphocytes ("lymphonets") emerged as a distinctive feature of the anti-cancer immune response. Lymphonets nucleated from small T cell clusters and incorporated B cells with increasing size. CXCR3-mediated trafficking modulated lymphonet size and number, but T cell antigen expression directed intratumoral localization. Lymphonets preferentially harbored TCF1+ PD-1+ progenitor CD8+ T cells involved in responses to immune checkpoint blockade (ICB) therapy. Upon treatment of mice with ICB or an antigen-targeted vaccine, lymphonets retained progenitor and gained cytotoxic CD8+ T cell populations, likely via progenitor differentiation. These data show that lymphonets create a spatial environment supportive of CD8+ T cell anti-tumor responses.

Lysine 2-hydroxyisobutyrylation of NAT10 promotes cancer metastasis in an ac4C-dependent manner

Posttranslational modifications add tremendous complexity to proteomes; however, gaps remain in knowledge regarding the function and regulatory mechanism of newly discovered lysine acylation modifications. Here, we compared a panel of non-histone lysine acylation patterns in metastasis models and clinical samples, and focused on 2-hydroxyisobutyrylation (Khib) due to its significant upregulation in cancer metastases. By the integration of systemic Khib proteome profiling in 20 paired primary esophageal tumor and metastatic tumor tissues with CRISPR/Cas9 functional screening, we identified N-acetyltransferase 10 (NAT10) as a substrate for Khib modification. We further showed that Khib modification at lysine 823 in NAT10 functionally contribute to metastasis. Mechanistically, NAT10 Khib modification enhances its interaction with deubiquitinase USP39, resulting in increased NAT10 protein stability. NAT10 in turn promotes metastasis by increasing NOTCH3 mRNA stability in an N4-acetylcytidine-dependent manner. Furthermore, we discovered a lead compound #7586-3507 that inhibited NAT10 Khib modification and showed efficacy in tumor models in vivo at a low concentration. Together, our findings bridge newly identified lysine acylation modifications with RNA modifications, thus providing novel insights into epigenetic regulation in human cancer. We propose that pharmacological inhibition of NAT10 K823 Khib modification constitutes a potential anti-metastasis strategy.

Identification of novel peptide inhibitors for oncogenic KRAS G12D as therapeutic options using mutagenesis-based remodeling and MD simulations

The Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) serves as a molecular switch, cycling between guanosine triphosphate (GTP)-bound and inactive guanosine diphosphate (GDP)-bound states. KRAS modulates numerous signal transduction pathways including the conventional RAF-MEK-ERK pathway. Mutations in the RAS genes have been linked to the formation of malignant tumors. Human malignancies typically show mutations in the Ras gene including HRAS, KRAS, and NRAS. Among all the mutations in exon 12 and exon 13 of the KRAS gene, the G12D mutation is more prevalent in pancreatic and lung cancer and accounts for around 41% of all G12 mutations, making them potential anticancer therapeutic targets. The present study is aimed at repurposing the peptide inhibitor KD2 of the KRAS G12D mutant. We employed an in-silico mutagenesis approach to design novel peptide inhibitors from the experimentally reported peptide inhibitor, and it was found that substitutions (N8W, N8I, and N8Y) might enhance the peptide's binding affinity toward the KRAS. Molecular dynamics simulations and binding energy calculations confirmed that the newly designed peptide inhibitors are stable and that their binding affinities are stronger as compared to the wild-type peptide. The detailed analysis revealed that newly designed peptides have the potential to inhibit KRAS/Raf interaction and the oncogenic signal of the KRAS G12D mutant. Our findings strongly suggest that these peptides should be tested and clinically validated to combat the oncogenic activity of KRAS.Communicated by Ramaswamy H. Sarma.

Experimental mouse models for translational human cancer research

The development and growth of tumors remains an important and ongoing threat to human life around the world. While advanced therapeutic strategies such as immune checkpoint therapy and CAR-T have achieved astonishing progress in the treatment of both solid and hematological malignancies, the malignant initiation and progression of cancer remains a controversial issue, and further research is urgently required. The experimental animal model not only has great advantages in simulating the occurrence, development, and malignant transformation mechanisms of tumors, but also can be used to evaluate the therapeutic effects of a diverse array of clinical interventions, gradually becoming an indispensable method for cancer research. In this paper, we have reviewed recent research progress in relation to mouse and rat models, focusing on spontaneous, induced, transgenic, and transplantable tumor models, to help guide the future study of malignant mechanisms and tumor prevention.

Role of RUNX3 in Restriction Point Regulation

A cell cycle is a series of events that takes place in a cell as it grows and divides. At the G₁ phase of cell cycle, cells monitor their cumulative exposure to specific signals and make the critical decision to pass through the restriction (R)-point. The R-point decision-making machinery is fundamental to normal differentiation, apoptosis, and G₁-S transition. Deregulation of this machinery is markedly associated with tumorigenesis. Therefore, identification of the molecular mechanisms that govern the R-point decision is one of the fundamental issues in tumor biology. RUNX3 is one of the genes frequently inactivated in tumors by epigenetic alterations. In particular, RUNX3 is downregulated in most K-RAS-activated human and mouse lung adenocarcinomas (ADCs). Targeted inactivation of Runx3 in the mouse lung induces adenomas (ADs), and markedly shortens the latency of ADC formation induced by oncogenic K-Ras. RUNX3 participates in the transient formation of R-point-associated activator (RPA-RX3-AC) complexes, which measure the duration of RAS signals and thereby protect cells against oncogenic RAS. This review focuses on the molecular mechanism by which the R-point participates in oncogenic surveillance.

Oncogenic KRAS signaling drives evasion of innate immune surveillance in lung adenocarcinoma by activating CD47

KRAS is one of the most frequently activated oncogenes in human cancers. Although the role of KRAS mutation in tumorigenesis and tumor maintenance has been extensively studied, the relationship between KRAS and the tumor immune microenvironment is not fully understood. Here, we identified a role of KRAS in driving tumor evasion from innate immune surveillance. In samples of lung adenocarcinoma from patients and Kras-driven genetic mouse models of lung cancer, mutant KRAS activated the expression of cluster of differentiation 47 (CD47), an antiphagocytic signal in cancer cells, leading to decreased phagocytosis of cancer cells by macrophages. Mechanistically, mutant KRAS activated PI3K/STAT3 signaling, which restrained miR-34a expression and relieved the posttranscriptional repression of miR-34a on CD47. In 3 independent cohorts of patients with lung cancer, the KRAS mutation status positively correlated with CD47 expression. Therapeutically, disruption of the KRAS/CD47 signaling axis with KRAS siRNA, the KRASG12C inhibitor AMG 510, or a miR-34a mimic suppressed CD47 expression, enhanced the phagocytic capacity of macrophages, and restored innate immune surveillance. Our results reveal a direct mechanistic link between active KRAS and innate immune evasion and identify CD47 as a major effector underlying the KRAS-mediated immunosuppressive tumor microenvironment.

Characterization of mutant versions of the R-RAS2/TC21 GTPase found in tumors

The R-RAS2 GTP hydrolase (GTPase) (also known as TC21) has been traditionally considered quite similar to classical RAS proteins at the regulatory and signaling levels. Recently, a long-tail hotspot mutation targeting the R-RAS2/TC21 Gln⁷² residue (Q72L) was identified as a potent oncogenic driver. Additional point mutations were also found in other tumors at low frequencies. Despite this, little information is available regarding the transforming role of these mutant versions and their relevance for the tumorigenic properties of already-transformed cancer cells. Here, we report that many of the RRAS2 mutations found in human cancers are highly transforming when expressed in immortalized cell lines. Moreover, the expression of endogenous R-RAS2^Q72L is important for maintaining optimal levels of PI3K and ERK activities as well as for the adhesion, invasiveness, proliferation, and mitochondrial respiration of ovarian and breast cancer cell lines. Endogenous R-RAS2^Q72L also regulates gene expression programs linked to both cell adhesion and inflammatory/immune-related responses. Endogenous R-RAS2^Q72L is also quite relevant for the in vivo tumorigenic activity of these cells. This dependency is observed even though these cancer cell lines bear concurrent gain-of-function mutations in genes encoding RAS signaling elements. Finally, we show that endogenous R-RAS2, unlike the case of classical RAS proteins, specifically localizes in focal adhesions. Collectively, these results indicate that gain-of-function mutations of R-RAS2/TC21 play roles in tumor initiation and maintenance that are not fully redundant with those regulated by classical RAS oncoproteins.

Double knock-in pig models with elements of binary Tet-On and phiC31 integrase systems for controllable and switchable gene expression

Inducible expression systems are indispensable for precise regulation and in-depth analysis of biological process. Binary Tet-On system has been widely employed to regulate transgenic expression by doxycycline. Previous pig models with tetracycline regulatory elements were generated through random integration. This process often resulted in uncertain expression and unpredictable phenotypes, thus hindering their applications. Here, by precise knock-in of binary Tet-On 3G elements into Rosa26 and Hipp11 locus, respectively, a double knock-in reporter pig model was generated. We characterized excellent properties of this system for controllable transgenic expression both in vitro and in vivo. Two attP sites were arranged to flank the tdTomato to switch reporter gene. Single or multiple gene replacement was efficiently and faithfully achieved in fetal fibroblasts and nuclear transfer embryos. To display the flexible application of this system, we generated a pig strain with Dox-inducing hKRAS^G12D expression through phiC31 integrase-mediated cassette exchange. After eight months of Dox administration, squamous cell carcinoma developed in the nose, mouth, and scrotum, which indicated this pig strain could serve as an ideal large animal model to study tumorigenesis. Overall, the established pig models with controllable and switchable transgene expression system will provide a facilitating platform for transgenic and biomedical research.

Fibrocytes boost tumor-supportive phenotypic switches in the lung cancer niche via the endothelin system

Fibrocytes are bone marrow-derived monocytic cells implicated in wound healing. Here, we identify their role in lung cancer progression/ metastasis. Selective manipulation of fibrocytes in mouse lung tumor models documents the central role of fibrocytes in boosting niche features and enhancing metastasis. Importantly, lung cancer patients show increased number of circulating fibrocytes and marked fibrocyte accumulation in the cancer niche. Using double and triple co-culture systems with human lung cancer cells, fibrocytes, macrophages and endothelial cells, we substantiate the central features of cancer-supporting niche: enhanced cancer cell proliferation and migration, macrophage activation, augmented endothelial cell sprouting and fibrocyte maturation. Upregulation of endothelin and its receptors are noted, and dual endothelin receptor blockade suppresses all cancer-supportive phenotypic alterations via acting on fibrocyte interaction with the cancer niche. We thus provide evidence for a crucial role of fibrocytes in lung cancer progression and metastasis, suggesting targets for treatment strategies.

Constructed the ceRNA network and predicted a FEZF1-AS1/miR-92b-3p/ZIC5 axis in colon cancer

The purpose of this study was to identify the role of FEZF1-AS1 in colon cancer and predicted the underlying mechanism. We extracted sequencing data of colon cancer patients from The Cancer Genome Atlas database, identified the differential expression of long noncoding RNA, microRNA, and messenger RNA, constructed a competitive endogenous RNA network, and then analyzed prognosis. Then, we used the enrichment analysis databases for functional analysis. Finally, we studied the FEZF1-AS1/miR-92b-3p/ZIC5 axis. We detected the expression of FEZF1-AS1, miR-92b-3p, and ZIC5 via quantitative reverse transcription-PCR, transfected colon cancer cell RKO with lentivirus and conducted FEZF1-AS1 knockdown, and performed cancer-related functional assays. It indicated that many RNA in the competitive endogenous RNA network, such as ZIC5, were predicted to be related to overall survival of colon cancer patients, and enrichment analysis showed cancer-related signaling pathways, such as PI3K/AKT signaling pathway. The expression of FEZF1-AS1 and ZIC5 was significantly higher and that of miR-92b-3p was lower in the colon cancer than in the normal colon tissues. FEZF1-AS1 promoted the migration, proliferation, as well as invasion of RKO. According to the prediction, FEZF1-AS1 and ZIC5 might competitively bind to miR-92b-3p, leading to the weakening of the inhibitory impact of miR-92b-3p on ZIC5 and increasing expression of ZIC5, thus further activating the PI3K/AKT signaling pathway, which led to the occurrence and development of colon cancer. The study suggested that FEZF1-AS1 might be an effective diagnosis biomarker for colon cancer.

Exogenous detection of 13C-glucose metabolism in tumor and diet-induced obesity models

Metabolic rewiring is a hallmark feature prevalent in cancer cells as well as insulin resistance (IR) associated with diet-induced obesity (DIO). For instance, tumor metabolism shifts towards an enhanced glycolytic state even under aerobic conditions. In contrast, DIO triggers lipid-induced IR by impairing insulin signaling and reducing insulin-stimulated glucose uptake. Based on physiological differences in systemic metabolism, we used a breath analysis approach to discriminate between different pathological states using glucose oxidation as a readout. We assessed glucose utilization in lung cancer-induced cachexia and DIO mouse models using a U-13C glucose tracer and stable isotope sensors integrated into an indirect calorimetry system. Our data showed increased 13CO2 expired by tumor-bearing (TB) mice and a reduction in exhaled 13CO2 in the DIO model. Taken together, our findings illustrate high glucose uptake and consumption in TB animals and decreased glucose uptake and oxidation in obese mice with an IR phenotype. Our work has important translational implications for the utility of stable isotopes in breath-based detection of glucose homeostasis in models of lung cancer progression and DIO.

The comparison of cancer gene mutation frequencies in Chinese and U.S. patient populations

Knowing the mutation frequency of cancer genes in China is crucial for reducing the global health burden. We integrate the tumor epidemiological statistics with cancer gene mutation rates identified in 11,948 cancer patients to determine their weighted proportions within a Chinese cancer patient cohort. TP53 (51.4%), LRP1B (13.4%), PIK3CA (11.6%), KRAS (11.1%), EGFR (10.6%), and APC (10.5%) are identified as the top mutated cancer genes in China. Additionally, 18 common cancer types from both China and U.S. cohorts are analyzed and classified into three patterns principally based upon TP53 mutation rates: TP53-Top, TP53-Plus, and Non-TP53. Next, corresponding similarities and prominent differences are identified upon comparing the mutational profiles from both cohorts. Finally, the potential population-specific and environmental risk factors underlying the disparities in cancer gene mutation rates between the U.S. and China are analyzed. Here, we show and compare the mutation rates of cancer genes in Chinese and U.S. population cohorts, for a better understanding of the associated etiological and epidemiological factors, which are important for cancer prevention and therapy.

Aberrant activation of KRAS in mouse theca-interstitial cells results in female infertility

KRAS plays critical roles in regulating a range of normal cellular events as well as pathological processes in many tissues mediated through a variety of signaling pathways, including ERK1/2 and AKT signaling, in a cell-, context- and development-dependent manner. The in vivo function of KRAS and its downstream targets in gonadal steroidogenic cells for the development and homeostasis of reproductive functions remain to be determined. To understand the functions of KRAS signaling in gonadal theca and interstitial cells, we generated a Kras mutant (tKrasMT) mouse line that selectively expressed a constitutively active KrasG12D in these cells. KrasG12D expression in ovarian theca cells did not block follicle development to the preovulatory stage. However, tKrasMT females failed to ovulate and thus were infertile. The phosphorylated ERK1/2 and forkhead box O1 (FOXO1) and total FOXO1 protein levels were markedly reduced in tKrasMT theca cells. KrasG12D expression in theca cells also curtailed the phosphorylation of ERK1/2 and altered the expression of several ovulation-related genes in gonadotropin-primed granulosa cells. To uncover downstream targets of KRAS/FOXO1 signaling in theca cells, we found that the expression of bone morphogenic protein 7 (Bmp7), a theca-specific factor involved in ovulation, was significantly elevated in tKrasMT theca cells. Chromosome immunoprecipitation assays demonstrated that FOXO1 interacted with the Bmp7 promoter containing forkhead response elements and that the binding activity was attenuated in tKrasMT theca cells. Moreover, Foxo1 knockdown caused an elevation, whereas Foxo1 overexpression resulted in an inhibition of Bmp7 expression, suggesting that KRAS signaling regulates FOXO1 protein levels to control Bmp7 expression in theca cells. Thus, the anovulation phenotype observed in tKrasMT mice may be attributed to aberrant KRAS/FOXO1/BMP7 signaling in theca cells. Our work provides the first in vivo evidence that maintaining normal KRAS activity in ovarian theca cells is crucial for ovulation and female fertility.

Delivery of Therapeutic miR-148b Mimic via Poly(β Amino Ester) Polyplexes for Post-transcriptional Gene Regulation and Apoptosis of A549 Cells

In this study, we utilized selectively modified, biodegradable polymer-based polyplexes to deliver custom, exogenous miR-148b mimics to induce apoptosis in human lung cancer (A549) cells. The gene regulatory effects of the payload miRNA mimics (miR-148b-3p) were first evaluated through bioinformatic analyses to uncover specific gene targets involved in critical carcinogenic pathways. Hyperbranched poly(β amino ester) polyplexes (hPBAE) loaded with custom miR-148b mimics were then developed for targeted therapy. When evaluated in vitro, these hPBAE-based polyplexes sustained high intracellular uptake, low cytotoxicity, and efficient escape from endosomes to deliver functionally intact miRNA mimics to the cytosol. High-resolution confocal microscopy revealed successful intracellular uptake, cell viability was assessed through qualitative fluorescence microscopy and fluorescence-based DNA quantification, and successful cytosolic delivery of intact miRNA mimics was evaluated using real-time polymerase chain reaction (RT-PCR) to demonstrate target gene knockdown. The hPBAE-miRNA mimic polyplexes were shown to induce apoptosis among A549 cells through direct modulation of intracellular protein expression, targeting multiple potential carcinogenic pathways at the gene level. These results indicated that spatially controlled miR-148b mimic delivery can promote efficient cancer cell death in vitro and may lead to an enhanced therapeutic design for in vivo application.

Targeting RAS in neuroblastoma: Is it possible?

Neuroblastoma is a common solid tumor in children and a leading cause of cancer death in children. Neuroblastoma exhibits genetic, morphological, and clinical heterogeneity that limits the efficacy of current monotherapies. With further research on neuroblastoma, the pathogenesis of neuroblastoma is found to be complex, and more and more treatment therapies are needed. The importance of personalized therapy is growing. Currently, various molecular features, including RAS mutations, are being used as targets for the development of new therapies for patients with neuroblastoma. A recent study found that RAS mutations are frequently present in recurrent neuroblastoma. RAS mutations have been shown to activate the MAPK pathway and play an important role in neuroblastoma. Treating RAS mutated neuroblastoma is a difficult challenge, but many preclinical studies have yielded effective results. At the same time, many of the therapies used to treat RAS mutated tumors also have good reference values for treating RAS mutated neuroblastoma. The success of KRAS-G12C inhibitors has greatly stimulated confidence in the direct suppression of RAS. This review describes the biological role of RAS and the frequency of RAS mutations in neuroblastoma. This paper focuses on the strategies, preclinical, and clinical progress of targeting carcinogenic RAS in neuroblastoma, and proposes possible prospects and challenges in the future.

Thymic Stromal Lymphopoietin Induction Suppresses Lung Cancer Development

Simple Summary

The recurrence rate for lung cancer is high after the removal of the primary tumor. Herein, we demonstrate the potential of immunotherapy against lung cancer by examining the impact of Thymic Stromal Lymphopoietin (TSLP) cytokine induction on early lung cancer development. TSLP induction suppresses the development of invasive lung tumors in a mouse model of spontaneous lung cancer. This cancer suppression is dependent on CD4⁺ T cells, which highlights the role of adaptive immune response in protection against lung cancer progression.

Abstract

Lung cancer is the leading cause of cancer deaths in the United States and across the world. Immunotherapies, which activate tumor-infiltrating cytotoxic T lymphocytes, have demonstrated efficacy for the treatment of advanced-stage lung cancer. However, the potential for harnessing the immune system against the early stages of lung carcinogenesis to prevent cancer development and recurrence remains unexplored. Using a mouse model of lung adenocarcinoma, we investigated the effects of thymic stromal lymphopoietin (TSLP) induction on early cancer development in the lungs. Herein, we demonstrate that systemic TSLP induction suppressed spontaneous lung cancer development in Kras^G12D mice. TSLP drove a significant CD4⁺ T cell response to block lung cancer progression from atypical alveolar hyperplasia to adenocarcinoma. Our findings suggest that TSLP can be used in the early stages of lung cancer development to trigger a lasting immunity in the tissue and prevent the development of advanced disease.

Air pollution particles hijack peroxidasin to disrupt immunosurveillance and promote lung cancer

Although fine particulate matter (FPM) in air pollutants and tobacco smoke is recognized as a strong carcinogen and global threat to public health, its biological mechanism for inducing lung cancer remains unclear. Here, by investigating FPM's bioactivities in lung carcinoma mice models, we discover that these particles promote lung tumor progression by inducing aberrant thickening of tissue matrix and hampering migration of antitumor immunocytes. Upon inhalation into lung tissue, these FPM particles abundantly adsorb peroxidasin (PXDN) - an enzyme mediating type IV collagen (Col IV) crosslinking - onto their surface. The adsorbed PXDN exerts abnormally high activity to crosslink Col IV via increasing the formation of sulfilimine bonds at the NC1 domain, leading to an overly dense matrix in the lung tissue. This disordered structure decreases the mobility of cytotoxic CD8+ T lymphocytes into the lung and consequently impairs the local immune surveillance, enabling the flourishing of nascent tumor cells. Meanwhile, inhibiting the activity of PXDN abolishes the tumor-promoting effect of FPM, indicating the key impact of aberrant PXDN activity on the tumorigenic process. In summary, our finding elucidates a new mechanism for FPM-induced lung tumorigenesis and identifies PXDN as a potential target for treatment or prevention of the FPM-relevant biological risks.

Ninjurin1 drives lung tumor formation and progression by potentiating Wnt/β-Catenin signaling through Frizzled2-LRP6 assembly

BACKGROUND

Cancer stem-like cells (CSCs) play a pivotal role in lung tumor formation and progression. Nerve injury-induced protein 1 (Ninjurin1, Ninj1) has been implicated in lung cancer; however, the pathological role of Ninj1 in the context of lung tumorigenesis remains largely unknown.

METHODS

The role of Ninj1 in the survival of non-small cell lung cancer (NSCLC) CSCs within microenvironments exhibiting hazardous conditions was assessed by utilizing patient tissues and transgenic mouse models where Ninj1 repression and oncogenic Kras^G12D/+ or carcinogen-induced genetic changes were induced in putative pulmonary stem cells (SCs). Additionally, NSCLC cell lines and primary cultures of patient-derived tumors, particularly Ninj1^high and Ninj1^low subpopulations and those with gain- or loss-of-Ninj1 expression, and also publicly available data were all used to assess the role of Ninj1 in lung tumorigenesis.

RESULTS

Ninj1 expression is elevated in various human NSCLC cell lines and tumors, and elevated expression of this protein can serve as a biomarker for poor prognosis in patients with NSCLC. Elevated Ninj1 expression in pulmonary SCs with oncogenic changes promotes lung tumor growth in mice. Ninj1^high subpopulations within NSCLC cell lines, patient-derived tumors, and NSCLC cells with gain-of-Ninj1 expression exhibited CSC-associated phenotypes and significantly enhanced survival capacities in vitro and in vivo in the presence of various cell death inducers. Mechanistically, Ninj1 forms an assembly with lipoprotein receptor-related protein 6 (LRP6) through its extracellular N-terminal domain and recruits Frizzled2 (FZD2) and various downstream signaling mediators, ultimately resulting in transcriptional upregulation of target genes of the LRP6/β-catenin signaling pathway.

CONCLUSIONS

Ninj1 may act as a driver of lung tumor formation and progression by protecting NSCLC CSCs from hostile microenvironments through ligand-independent activation of LRP6/β-catenin signaling.

Engineered mesenchymal stem cell-derived exosomes with high CXCR4 levels for targeted siRNA gene therapy against cancer

Gene therapy has been used in a variety of diseases and shows brilliant anticancer or cancer suppression effects. Gene therapy is gradually evolving as the most compelling frontier hotspot in the field of cancer therapy. The current vehicles used in gene therapy have poor safety and low delivery efficiency, and thus, it is urgent to develop novel delivery vehicles for gene therapy. Due to the excellent stability and biosafety of exosomes, their use as drug carriers for novel nucleic acid therapy is in full swing, revealing huge prospects for clinical application. Mesenchymal stem cells (MSCs) have a natural homing property and can spontaneously accumulate at injury sites, inflammation sites, and even tumour sites. This feature is attributed to a variety of tropism factors expressed on their surface; for example, CXC chemokine receptor type 4 (CXCR4) can specifically bind to the highly expressed stromal cell derived factor-1 (SDF-1) on the tumour surface, which is essential for accumulation of MSCs at the tumour site. The mesenchymal stem cells used in this study were genetically engineered to obtain exosomes with high CXCR4 expression as carriers for targeted gene-drug delivery, and then, the Survivin gene was loaded via electrotransformation to construct a brand-new gene-drug delivery system (CXCR4^high Exo/si-Survivin). Finally, related in vivo and in vitro experiments were conducted. We observed that the new delivery system can efficiently aggregate at the tumour site and release siRNA into tumour cells, knocking down the Survivin gene in tumour cells in vivo and thereby inhibiting tumour growth. This new gene-drug delivery system has tremendous clinical transformation value and provides a new strategy for clinical treatment of tumours.