Streptococcus anginosus promotes gastric inflammation, atrophy, and tumorigenesis in mice.

Streptococcus anginosus (S. anginosus) was enriched in the gastric mucosa of patients with gastric cancer (GC). Here, we show that S. anginosus colonized the mouse stomach and induced acute gastritis. S. anginosus infection spontaneously induced progressive chronic gastritis, parietal cell atrophy, mucinous metaplasia, and dysplasia in conventional mice, and the findings were confirmed in germ-free mice. In addition, S. anginosus accelerated GC progression in carcinogen-induced gastric tumorigenesis and YTN16 GC cell allografts. Consistently, S. anginosus disrupted gastric barrier function, promoted cell proliferation, and inhibited apoptosis. Mechanistically, we identified an S. anginosus surface protein, TMPC, that interacts with Annexin A2 (ANXA2) receptor on gastric epithelial cells. Interaction of TMPC with ANXA2 mediated attachment and colonization of S. anginosus and induced mitogen-activated protein kinase (MAPK) activation. ANXA2 knockout abrogated the induction of MAPK by S. anginosus. Thus, this study reveals S. anginosus as a pathogen that promotes gastric tumorigenesis via direct interactions with gastric epithelial cells in the TMPC-ANXA2-MAPK axis.

Targeting squalene epoxidase restores anti-PD-1 efficacy in metabolic dysfunction-associated steatohepatitis-induced hepatocellular carcinoma.

OBJECTIVE: Squalene epoxidase (SQLE) promotes metabolic dysfunction-associated steatohepatitis-associated hepatocellular carcinoma (MASH-HCC), but its role in modulating the tumour immune microenvironment in MASH-HCC remains unclear. DESIGN: We established hepatocyte-specific Sqle transgenic (tg) and knockout mice, which were subjected to a choline-deficient high-fat diet plus diethylnitrosamine to induce MASH-HCC. SQLE function was also determined in orthotopic and humanised mice. Immune landscape alterations of MASH-HCC mediated by SQLE were profiled by single-cell RNA sequencing and flow cytometry. RESULTS: Hepatocyte-specific Sqle tg mice exhibited a marked increase in MASH-HCC burden compared with wild-type littermates, together with decreased tumour-infiltrating functional IFN-γ+ and Granzyme B+ CD8+ T cells while enriching Arg-1+ myeloid-derived suppressor cells (MDSCs). Conversely, hepatocyte-specific Sqle knockout suppressed tumour growth with increased cytotoxic CD8+ T cells and reduced Arg-1+ MDSCs, inferring that SQLE promotes immunosuppression in MASH-HCC. Mechanistically, SQLE-driven cholesterol accumulation in tumour microenvironment underlies its effect on CD8+ T cells and MDSCs. SQLE and its metabolite, cholesterol, impaired CD8+ T cell activity by inducing mitochondrial dysfunction. Cholesterol depletion in vitro abolished the effect of SQLE-overexpressing MASH-HCC cell supernatant on CD8+ T cell suppression and MDSC activation, whereas cholesterol supplementation had contrasting functions on CD8+ T cells and MDSCs treated with SQLE-knockout supernatant. Targeting SQLE with genetic ablation or pharmacological inhibitor, terbinafine, rescued the efficacy of anti-PD-1 treatment in MASH-HCC models. CONCLUSION: SQLE induces an impaired antitumour response in MASH-HCC via attenuating CD8+ T cell function and augmenting immunosuppressive MDSCs. SQLE is a promising target in boosting anti-PD-1 immunotherapy for MASH-HCC.

Lactococcus lactis HkyuLL 10 suppresses colorectal tumourigenesis and restores gut microbiota through its generated alpha-mannosidase.

OBJECTIVE: Probiotic Lactococcus lactis is known to confer health benefits to humans. Here, we aimed to investigate the role of L. lactis in colorectal cancer (CRC). DESIGN: L. lactis abundance was evaluated in patients with CRC (n=489) and healthy individuals (n=536). L. lactis was isolated from healthy human stools with verification by whole genome sequencing. The effect of L. lactis on CRC tumourigenesis was assessed in transgenic Apc Min/+ mice and carcinogen-induced CRC mice. Faecal microbiota was profiled by metagenomic sequencing. Candidate proteins were characterised by nano liquid chromatography-mass spectrometry. Biological function of L. lactis conditioned medium (HkyuLL 10-CM) and functional protein was studied in human CRC cells, patient-derived organoids and xenograft mice. RESULTS: Faecal L. lactis was depleted in patients with CRC. A new L. lactis strain was isolated from human stools and nomenclated as HkyuLL 10. HkyuLL 10 supplementation suppressed CRC tumourigenesis in Apc Min/+ mice, and this tumour-suppressing effect was confirmed in mice with carcinogen-induced CRC. Microbiota profiling revealed probiotic enrichment including Lactobacillus johnsonii in HkyuLL 10-treated mice. HkyuLL 10-CM significantly abrogated the growth of human CRC cells and patient-derived organoids. Such protective effect was attributed to HkyuLL 10-secreted proteins, and we identified that α-mannosidase was the functional protein. The antitumourigenic effect of α-mannosidase was demonstrated in human CRC cells and organoids, and its supplementation significantly reduced tumour growth in xenograft mice. CONCLUSION: HkyuLL 10 suppresses CRC tumourigenesis in mice through restoring gut microbiota and secreting functional protein α-mannosidase. HkyuLL 10 administration may serve as a prophylactic measure against CRC.

Out of the cycle: Impact of cell cycle aberrations on cancer metabolism and metastasis.

The use of cell cycle inhibitors has necessitated a better understanding of the cell cycle in tumor biology to optimize the therapeutic approach. Cell cycle aberrations are common in cancers, and it is increasingly acknowledged that these aberrations exert oncogenic effects beyond the cell cycle. Multiple facets such as cancer metabolism, immunity and metastasis are also affected, all of which are beyond the effect of cell proliferation alone. This review comprehensively summarized the important recent findings and advances in these interrelated processes. In cancer metabolism, cell cycle regulators can modulate various pathways in aerobic glycolysis, glucose uptake and gluconeogenesis, mainly through transcriptional regulation and kinase activities. Amino acid metabolism is also regulated through cell cycle progression. On cancer metastasis, metabolic plasticity, immune evasion, tumor microenvironment adaptation and metastatic site colonization are intricately related to the cell cycle, with distinct regulatory mechanisms at each step of invasion and dissemination. Throughout the synthesis of current understanding, knowledge gaps and limitations in the literature are also highlighted, as are new therapeutic approaches such as combinational therapy and challenges in tackling emerging targeted therapy resistance. A greater understanding of how the cell cycle modulates diverse aspects of cancer biology can hopefully shed light on identifying new molecular targets by harnessing the vast potential of the cell cycle.

Targeting YAP1/TAZ in nonsmall-cell lung carcinoma: From molecular mechanisms to precision medicine.

Accumulating evidence has underscored the importance of the Hippo-YAP1 signaling in lung tissue homeostasis, whereas its deregulation induces tumorigenesis. YAP1 and its paralog TAZ are the key downstream effectors tightly controlled by the Hippo pathway. YAP1/TAZ exerts oncogenic activities by transcriptional regulation via physical interaction with TEAD transcription factors. In solid tumors, Hippo-YAP1 crosstalks with other signaling pathways such as Wnt/ß-catenin, receptor tyrosine kinase cascade, Notch and TGF-ß to synergistically drive tumorigenesis. As YAP1/TAZ expression is significantly correlated with unfavorable outcomes for the patients, small molecules have been developed for targeting YAP1/TAZ to get a therapeutic effect. In this review, we summarize the recent findings on the deregulation of Hippo-YAP1 pathway in nonsmall cell lung carcinoma, discuss the molecular mechanisms of its dysregulation in leading to tumorigenesis, explore the therapeutic strategies for targeting YAP1/TAZ, and provide the research directions for deep investigation. We believe that detailed delineation of Hippo-YAP1 regulation in tumorigenesis provides novel insight for accurate therapeutic intervention.

Cancer-associated fibroblasts in nonsmall cell lung cancer: From molecular mechanisms to clinical implications.

Lung cancer is the common and leading cause of cancer death worldwide. The tumor microenvironment has been recognized to be instrumental in tumorigenesis. To have a deep understanding of the molecular mechanism of nonsmall cell lung carcinoma (NSCLC), cancer-associated fibroblasts (CAFs) have gained increasing research interests. CAFs belong to the crucial and dominant cell population in the tumor microenvironment to support the cancer cells. The interplay and partnership between cancer cells and CAFs contribute to each stage of tumorigenesis. CAFs exhibit prominent heterogeneity and secrete different kinds of cytokines and chemokines, growth factors and extracellular matrix proteins involved in cancer cell proliferation, invasion, metastasis and chemoresistance. Many studies focused on the protumorigenic functions of CAFs, yet many challenges about the heterogeneity of CAFS remain unresolved. This review comprehensively summarized the tumor-promoting role and molecular mechanisms of CAFs in NSCLC, including their origin, phenotypic changes and heterogeneity and their functional roles in carcinogenesis. Meanwhile, we also highlighted the updated molecular classifications based on the molecular features and functional roles of CAFs. With the development of cutting-edge platforms and further investigations of CAFs, novel therapeutic strategies for accurately targeting CAFs in NSCLC may be developed based on the increased understanding of the relevant molecular mechanisms.

Specific targeting of point mutations in EGFR L858R-positive lung cancer by CRISPR/Cas9.

Cancer cells are defined genetically by the mutations they harbor, commonly single nucleotide substitutions. Therapeutic approaches which specifically target cancer cells by recognizing these defining genetic aberrations are expected to exhibit minimal side-effects. However, current protein-based targeted therapy is greatly limited by the range of genes that can be targeted, as well as by acquired resistance. We hypothesized that a therapeutic oligonucleotide-based strategy may address this need of specific cancer targeting. We used CRISPR/Cas9 system to target a commonly occurring EGFR point mutation, L858R, with an oligonucleotide guide that recognizes L858R as the suitable protospacer-adjacent motif (PAM) sequence for DNA cleavage. We found that this strategy, which utilized PAM to differentiate cancer mutation from normal, afforded high specificity to the extent of a single nucleotide substitution. The anti-L858R vehicle resulted in selective genome cleavage only in L858R mutant cells, as detected by Sanger sequencing and T7 Endonuclease I assay. Wild-type cells were unaffected by the same treatment. Digital PCR revealed 37.9 ± 8.57% of L858R gene copies were targeted in mutant. Only treated mutant cells, but not wild-type cells, showed reduction in EGFR expression and decreased cell proliferation. Treated mutant cells also formed smaller tumor load in vivo. This targeting approach is expected to be able to target a significant subset of the 15-35% cancer mutations with C > G, A > G, and T > G point mutations. Thus, this strategy may serve as a useful approach to target cancer-defining mutations with specificity, to the extent of differentiating the change of a single nucleotide.

Emergence of CD26+ Cancer Stem Cells with Metastatic Properties in Colorectal Carcinogenesis.

Colorectal cancer results from genetic aberrations which accumulate over a long period of time, with malignant and metastatic properties acquired at a relatively late stage. A subpopulation of CD26+ colorectal cancer stem cells are known to be implicated in metastasis. We quantified CD26+ cancer cells in 11 primary tumor samples by flow cytometry, and showed that tumors having confirmed or suspected metastases harbored a relatively high CD26+ level in these samples. We hypothesized that this subpopulation of cancer stem cells arises in the late stage of carcinogenesis from the bulk of tumor daughter cells which are CD26-. The manipulation of PIK3CA and TP53, two genes commonly deregulated in the late stage, had an effect on the maintenance of the CD26+ cell population. When CD26- tumor daughter cells were sorted and cultured, the emergence of tumor spheres containing CD26+ cells occurred. These findings shed light to the origin of colorectal cancer stem cells with metastatic properties, which has an implication on conventional treatments by surgery or adjuvant chemotherapy for tumor debulking.

Nine-year experience of doxorubicin-eluting beads chemoembolization for hepatocellular carcinoma.

BACKGROUND: Chemoembolization with doxorubucin-eluting beads (DEB) has been used to treat hepatocellular carcinoma (HCC) since 2007. This study compared the efficacy and survival between transarterial chemoembolization (TACE) with DEB and conventional approach (cTACE) in HCC treatment. METHODS: This retrospective case-control study compared the overall survival and tumor response of HCC patients to cTACE (n=190) and DEB (n=143) by the reassessment of computed tomography and serum alpha-fetoprotein (AFP). Multivariate analysis was used to determine the factors affecting tumor response. RESULTS: The median post-treatment to pre-treatment AFP level was 0.8 for a DEB session (n=258) and 1.0 for a cTACE session (n=452), showing a significantly greater decrease in AFP after DEB (P<0.05). More patients in the DEB group achieved objective response (complete and partial) compared with those in the cTACE group (P<0.05). Objective tumor response after DEB vs cTACE was 34.8% vs 15.4% in 0-3 months (P=0.001), 37.1% vs 20.0% in 3-6 months (P<0.05), and 50.0% vs 30.0% in 6-12 months (P=0.093). DEB predicted a 3.604 times odds of achieving at least one objective tumor response in a patient when compared to cTACE (P<0.0001). The median survival from first transcatheter therapy of patients having undergone at least once DEB was 12.53 months, while those having received cTACE only was 10.53 months (P=0.086). A tendency of improved survival appeared to maintain until >80 months after the first TACE session in the DEB group. CONCLUSION: DEB is a safe alternative to cTACE in HCC patients with better therapeutic efficacy.

Peptostreptococcus anaerobius mediates anti-PD1 therapy resistance and exacerbates colorectal cancer via myeloid-derived suppressor cells in mice.

Bacteria such as the oral microbiome member Peptostreptococcus anaerobius can exacerbate colorectal cancer (CRC) development. Little is known regarding whether these immunomodulatory bacteria also affect antitumour immune checkpoint blockade therapy. Here we show that administration of P. anaerobius abolished the efficacy of anti-PD1 therapy in mouse models of CRC. P. anaerobius both induced intratumoral myeloid-derived suppressor cells (MDSCs) and stimulated their immunosuppressive activities to impair effective T cell responses. Mechanistically, P. anaerobius administration activated integrin α2ß1-NF-κB signalling in CRC cells to induce secretion of CXCL1 and recruit CXCR2+ MDSCs into tumours. The bacterium also directly activated immunosuppressive activity of intratumoral MDSCs by secreting lytC_22, a protein that bound to the Slamf4 receptor on MDSCs and promoted ARG1 and iNOS expression. Finally, therapeutic targeting of either integrin α2ß1 or the Slamf4 receptor were revealed as promising strategies to overcome P. anaerobius-mediated resistance to anti-PD1 therapy in CRC.

RUVBL1/2 Blockade Targets YTHDF1 Activity to Suppress m6A-Dependent Oncogenic Translation and Colorectal Tumorigenesis.

The N6-methyladenosine (m6A) RNA binding protein YTHDF1 is frequently overexpressed in colorectal cancer (CRC) and drives chemotherapeutic resistance. To systematically identify druggable targets in CRC with high expression of YTHDF1, we employed a CRISPR/Cas9 screening strategy that revealed RUVBL1 and RUVBL2 as putative targets.RUVBL1/2 were overexpressed in primary CRC samples and represented independent predictors of poor patient prognosis. Functionally, loss of RUVBL1/2 preferentially impaired the growth ofYTHDF1-high CRC cells, patient-derived primary CRC organoids, and subcutaneous xenografts. Mechanistically, YTHFD1 and RUVBL1/2 formed a positive feed-forward circuit to accelerate oncogenic translation. YTHDF1 bound to m6A-modified RUVBL1/2 mRNA to promote translation initiation and protein expression. Co-IP and mass spectrometry identified that RUVBL1/2 reciprocally interacted with YTHDF1 at 40S translation initiation complexes. Consequently, RUVBL1/2 depletion stalled YTHDF1-driven oncogenic translation and nascent protein biosynthesis, leading to proliferative arrest and apoptosis. Ribo-seq revealed that RUVBL1/2 loss impaired the activation of MAPK, RAS and PI3K-AKT signaling induced by YTHDF1. Finally, blockade of RUVBL1/2 by the pharmacological inhibitor CB6644 or vesicle-like nanoparticle-encapsulated siRNAs preferentially arrested the growth of YTHDF1-expressing CRC in vitro and in vivo. Together, this study uncovered that RUVBL1/2 are potential prognostic markers and druggable targets that regulate protein translation in YTHDF1-high CRC.

Peptostreptococcus stomatis promotes colonic tumorigenesis and receptor tyrosine kinase inhibitor resistance by activating ERBB2-MAPK.

Peptostreptococcus stomatis (P. stomatis) is enriched in colorectal cancer (CRC), but its causality and translational implications in CRC are unknown. Here, we show that P. stomatis accelerates colonic tumorigenesis in ApcMin/+ and azoxymethane/dextran sodium sulfate (AOM-DSS) models by inducing cell proliferation, suppressing apoptosis, and impairing gut barrier function. P. stomatis adheres to CRC cells through its surface protein fructose-1,6-bisphosphate aldolase (FBA) that binds to the integrin α6/ß4 receptor on CRC cells, leading to the activation of ERBB2 and the downstream MEK-ERK-p90 cascade. Blockade of the FBA-integrin α6/ß4 abolishes ERBB2-mitogen-activated protein kinase (MAPK) activation and the protumorigenic effect of P. stomatis. P. stomatis-driven ERBB2 activation bypasses receptor tyrosine kinase (RTK) blockade by EGFR inhibitors (cetuximab, erlotinib), leading to drug resistance in xenograft and spontaneous CRC models of KRAS-wild-type CRC. P. stomatis also abrogates BRAF inhibitor (vemurafenib) efficacy in BRAFV600E-mutant CRC xenografts. Thus, we identify P. stomatis as an oncogenic bacterium and a contributory factor for non-responsiveness to RTK inhibitors in CRC.

SMARCA4 deficiency and mutations are frequent in large cell lung carcinoma and are prognostically significant.

SMARCA4 mutation has emerged as a marker of poor prognosis in lung cancer and has potential predictive value in cancer treatment, but recommendations for which patients require its investigation are lacking. We comprehensively studied SMARCA4 alterations and the clinicopathological significance in a large cohort of immunohistochemically-subtyped non-small cell lung cancer (NSCLC). A total of 1416 patients was studied for the presence of SMARCA4 deficiency by immunohistochemistry (IHC). Thereafter, comprehensive sequencing of tumours was performed for 397 of these patients to study the mutational spectrum of SWI/SNF and SMARCA4 aberrations. IHC evidence of SMARCA4 deficiency was found in 2.9% of NSCLC. Of the sequenced tumours, 38.3% showed aberration in SWI/SNF complex, and 9.3% had SMARCA4 mutations. Strikingly, SMARCA4 aberrations were much more prevalent in large cell carcinoma (LCC) than other histological tumour subtypes. SMARCA4-deficient and SMARCA4-mutated tumours accounted for 40.5% and 51.4% of all LCC, respectively. Multivariable analyses confirmed SMARCA4 mutation was an independent prognostic factor in lung cancer. The immunophenotype of a subset of these tumours frequently showed TTF1 negativity and HepPAR1 positivity. SMARCA4 mutation or its deficiency was associated with positive smoking history and poor prognosis. It also demonstrated mutual exclusion with EGFR mutation. Taken together, the high incidence of SMARCA4 aberrations in LCC may indicate its diagnostic and prognostic value. Our study established the necessity of SMARCA4 IHC in the identification of SMARCA4-aberrant tumours, and this may be of particular importance in LCC and tumours without known driver events.

The artificial intelligence-based model ANORAK improves histopathological grading of lung adenocarcinoma.

The introduction of the International Association for the Study of Lung Cancer grading system has furthered interest in histopathological grading for risk stratification in lung adenocarcinoma. Complex morphology and high intratumoral heterogeneity present challenges to pathologists, prompting the development of artificial intelligence (AI) methods. Here we developed ANORAK (pyrAmid pooliNg crOss stReam Attention networK), encoding multiresolution inputs with an attention mechanism, to delineate growth patterns from hematoxylin and eosin-stained slides. In 1,372 lung adenocarcinomas across four independent cohorts, AI-based grading was prognostic of disease-free survival, and further assisted pathologists by consistently improving prognostication in stage I tumors. Tumors with discrepant patterns between AI and pathologists had notably higher intratumoral heterogeneity. Furthermore, ANORAK facilitates the morphological and spatial assessment of the acinar pattern, capturing acinus variations with pattern transition. Collectively, our AI method enabled the precision quantification and morphology investigation of growth patterns, reflecting intratumoral histological transitions in lung adenocarcinoma.

FOXP4 is a Direct YAP1 Target that Promotes Gastric Cancer Stemness and Drives Metastasis.

The Hippo-YAP1 pathway is an evolutionally conserved signaling cascade that controls organ size and tissue regeneration. Dysregulation of Hippo-YAP1 signaling promotes initiation and progression of several types of cancer, including gastric cancer (GC). As the Hippo-YAP1 pathway regulates expression of thousands of genes, it is important to establish which target genes contribute to the oncogenic program driven by YAP1 to identify strategies to circumvent it. Here, we identified a vital role of FOXP4 in YAP1-driven gastric carcinogenesis by maintaining stemness and promoting peritoneal metastasis. Loss of FOXP4 impaired GC spheroid formation and reduced stemness marker expression, while FOXP4 upregulation potentiated cancer cell stemness. RNA-seq analysis revealed SOX12 as downstream target of FOXP4, and functional studies established that SOX12 supports stemness in YAP1-induced carcinogenesis. A small molecule screen identified 42-(2-Tetrazolyl)rapamycin as a FOXP4 inhibitor, and targeting FOXP4 suppressed GC tumor growth and enhanced the efficacy of 5-FU chemotherapy in vivo. Collectively, these findings revealed that FOXP4 upregulation by YAP1 in GC regulates stemness and tumorigenesis by upregulating SOX12. Targeting the YAP1-FOXP4-SOX12 axis represents a potential therapeutic strategy for GC.

Interpretation of Lung Cancer Plasma EGFR Mutation Tests in the Clinical Setting.

OBJECTIVES: Comprehensive data synthesis of the clinical parameters that affect plasma EGFR mutation test results in non-small cell lung carcinoma is lacking. Although individual studies have suggested a variety of patient characteristics that can affect diagnostic accuracy, no unified conclusion has been reached. METHODS: We analyzed 170 plasma EGFR mutation tests performed between 2015 and 2021 at our institution and carried out a systematic review and meta-analysis to identify clinical and imaging features that correlate with plasma EGFR mutation test sensitivity. RESULTS: Data synthesis from 14 studies of 2,576 patients revealed that patients with stage IV disease had a significantly lower false-negative rate than those with stage I through III disease. For our institutional cohort, which consisted of 75 paired plasma and tissue tests that were assessable for diagnostic accuracy, the overall sensitivity was 70.59% (95% confidence interval, 56.17%-82.51%). Patients who had distant metastases and more suspicious lymph nodes on imaging findings correlated with a low false-negative rate. CONCLUSIONS: While interpreting plasma EGFR mutation results, extra caution should be exercised for patients with early-stage, localized disease to accommodate the possibility of false-negative results. These meta-analyses and clinical data may enable clinicians to make evidence-based judgments for individual patients.

METTL3 drives NAFLD-related hepatocellular carcinoma and is a therapeutic target for boosting immunotherapy.

Non-alcoholic fatty liver disease (NAFLD) is an emerging risk factor of hepatocellular carcinoma (HCC). However, the mechanism and target therapy of NAFLD-HCC are still unclear. Here, we identify that the N6-methyladenosine (m6A) methyltransferase METTL3 promotes NAFLD-HCC. Hepatocyte-specific Mettl3 knockin exacerbated NAFLD-HCC formation, while Mettl3 knockout exerted the opposite effect in mice. Single-cell RNA sequencing revealed that METTL3 suppressed antitumor immune response by reducing granzyme B (GZMB+) and interferon gamma-positive (IFN-γ+) CD8+ T cell infiltration, thereby facilitating immune escape. Mechanistically, METTL3 mediates sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP) mRNA m6A to promote its translation, leading to the activation of cholesterol biosynthesis. This enhanced secretion of cholesterol and cholesteryl esters that impair CD8+ T cell function in the tumor microenvironment. Targeting METTL3 by single-guide RNA, nanoparticle small interfering RNA (siRNA), or pharmacological inhibitor (STM2457) in combination with anti-programmed cell death protein 1 (PD-1) synergized to reinvigorate cytotoxic CD8+ T cells and mediate tumor regression. Together, METTL3 is a therapeutic target in NAFLD-HCC, especially in conjunction with immune checkpoint blockade (ICB) therapy.

MLK4 promotes glucose metabolism in lung adenocarcinoma through CREB-mediated activation of phosphoenolpyruvate carboxykinase and is regulated by KLF5.

MLK4, a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family, has been implicated in cancer progression. However, its role in lung adenocarcinoma has not been characterized. Here, we showed that MLK4 was overexpressed in a significant subset of lung adenocarcinoma, associated with a worse prognosis, and exerted an oncogenic function in vitro and in vivo. Bioinformatics analyses of clinical datasets identified phosphoenolpyruvate carboxykinase 1 (PCK1) as a novel target of MLK4. We validated that MLK4 regulated PCK1 expression at transcriptional level, by phosphorylating the transcription factor CREB, which in turn mediated PCK1 expression. We further demonstrated that PCK1 is an oncogenic factor in lung adenocarcinoma. Given the importance of PCK1 in the regulation of cellular metabolism, we next deciphered the metabolic effects of MLK4. Metabolic and mass spectrometry analyses showed that MLK4 knockdown led to significant reduction of glycolysis and decreased levels of glycolytic pathway metabolites including phosphoenolpyruvate and lactate. Finally, the promoter analysis of MLK4 unravelled a binding site of transcription factor KLF5, which in turn, positively regulated MLK4 expression in lung adenocarcinoma. In summary, we have revealed a KLF5-MLK4-PCK1 signalling pathway involved in lung tumorigenesis and established an unusual link between MAP3K signalling and cancer metabolism.

Parvimonas micra promotes colorectal tumorigenesis and is associated with prognosis of colorectal cancer patients.

Large-scale fecal shotgun metagenomic sequencing revealed the high abundance of Parvimonas micra in colorectal cancer (CRC) patients. We investigated the role and clinical significance of P. micra in colorectal tumorigenesis. The abundance of P. micra was examined in 309 fecal samples and 165 colon biopsy tissues of CRC patients and healthy subjects. P. micra was significantly enriched in fecal samples from 128 CRC patients compared to 181 healthy subjects (P < 0.0001); and in colon tissue biopsies from 52 CRC patients compared to 61 healthy subjects (P < 0.0001). Multivariate analysis showed that P. micra is an independent risk factor of poor survival in CRC patients (Hazard Ratio: 1.93). P. micra strain was isolated from feces of a CRC patient. Apcmin/+ mice gavaged with P. micra showed significantly higher tumor burden and tumor load (both P < 0.01). Consistently, gavage of P. micra significantly promoted colonocyte proliferation in conventional mice, which was further confirmed by germ-free mice. P. micra colonization up-regulated genes involved in cell proliferation, stemness, angiogenesis and invasiveness/metastasis; and enhanced Th17 cells infiltration and expression of Th17 cells-secreted cytokines (Il-17, Il-22, and Il-23) in the colon of Apcmin/+, conventional and germ-free mice. P. micra-conditioned medium significantly promoted the differentiation of CD4+ T cells to Th17 cells (IL-17+CD4+ phenotype) and enhanced the oncogenic Wnt signaling pathway. In conclusion, P. micra promoted colorectal tumorigenesis in mice by inducing colonocyte proliferation and altering Th17 immune response. P. micra may act as a prognostic biomarker for poor survival of CRC patients.

The cholesterol uptake regulator PCSK9 promotes and is a therapeutic target in APC/KRAS-mutant colorectal cancer.

Therapeutic targeting of KRAS-mutant colorectal cancer (CRC) is an unmet need. Here, we show that Proprotein Convertase Subtilisin/Kexin type 9 (PSCK9) promotes APC/KRAS-mutant CRC and is a therapeutic target. Using CRC patient cohorts, isogenic cell lines and transgenic mice, we identify that de novo cholesterol biosynthesis is induced in APC/KRAS mutant CRC, accompanied by increased geranylgeranyl diphosphate (GGPP)─a metabolite necessary for KRAS activation. PCSK9 is the top up-regulated cholesterol-related gene. PCSK9 depletion represses APC/KRAS-mutant CRC cell growth in vitro and in vivo, whereas PCSK9 overexpression induces oncogenesis. Mechanistically, PCSK9 reduces cholesterol uptake but induces cholesterol de novo biosynthesis and GGPP accumulation. GGPP is a pivotal metabolite downstream of PCSK9 by activating KRAS/MEK/ERK signaling. PCSK9 inhibitors suppress growth of APC/KRAS-mutant CRC cells, organoids and xenografts, especially in combination with simvastatin. PCSK9 overexpression predicts poor survival of APC/KRAS-mutant CRC patients. Together, cholesterol homeostasis regulator PCSK9 promotes APC/KRAS-mutant CRC via GGPP-KRAS/MEK/ERK axis and is a therapeutic target.