The non-essential amino acids serine and glycine are used in multiple anabolic processes that support cancer cell growth and proliferation (reviewed in ref. 1). While some cancer cells upregulate de ...novo serine synthesis, many others rely on exogenous serine for optimal growth. Restriction of dietary serine and glycine can reduce tumour growth in xenograft and allograft models. Here we show that this observation translates into more clinically relevant autochthonous tumours in genetically engineered mouse models of intestinal cancer (driven by Apc inactivation) or lymphoma (driven by Myc activation). The increased survival following dietary restriction of serine and glycine in these models was further improved by antagonizing the anti-oxidant response. Disruption of mitochondrial oxidative phosphorylation (using biguanides) led to a complex response that could improve or impede the anti-tumour effect of serine and glycine starvation. Notably, Kras-driven mouse models of pancreatic and intestinal cancers were less responsive to depletion of serine and glycine, reflecting an ability of activated Kras to increase the expression of enzymes that are part of the serine synthesis pathway and thus promote de novo serine synthesis.
High mucosal and fecal concentrations of the antimicrobial siderophore-binding peptide Lipocalin-2 (Lcn2) are observed in inflammatory bowel disease. However, Lcn2 function in chronic intestinal ...inflammation remains unclear. Here, we demonstrate that Lcn2 protects from early-onset colitis and spontaneous emergence of right-sided colonic tumors resulting from IL-10 deficiency. Exacerbated inflammation in Lcn2–/–/Il10–/– mice is driven by IL-6, which also controls tumorigenesis. Lcn2–/–/Il10–/– mice exhibit profound alterations in gut microbial composition, which contributes to inflammation and tumorigenesis, as demonstrated by the transmissibility of the phenotype and protection conferred by antibiotics. Specifically, facultative pathogenic Alistipes spp. utilize enterobactin as iron source, bloom in Lcn2–/–/Il10–/– mice, and are sufficient to induce colitis and right-sided tumors when transferred into Il10–/– mice. Our results demonstrate that Lcn2 protects against intestinal inflammation and tumorigenesis associated with alterations in the microbiota.
Display omitted
•Antimicrobial peptide Lipocalin-2 (Lcn2) is strongly induced in Il10–/– colitic mice•Lcn2 deficiency exacerbates Il10–/– colitis and causes spontaneous right-sided tumors•Inflammation and tumorigenesis are due to altered gut microbiota and are transmissible•Alistipes spp. is sufficient to induce colitis and site-specific tumors in Il10–/– mice
Lipocalin-2 is a host defense protein that is upregulated during inflammation. Moschen et al. demonstrate that Lipocalin-2 protects from intestinal inflammation and spontaneous tumor formation in experimental colitis through its impact on microbial composition, specifically Alistipes spp., which induces colitis and tumors when transferred to Il10–/– mice.
Gastroenteropancreatic Neuroendocrine Tumors Cives, Mauro; Strosberg, Jonathan R.
CA: a cancer journal for clinicians,
November/December 2018, Volume:
68, Issue:
6
Journal Article
Peer reviewed
Open access
Neuroendocrine tumors (NETs) are heterogeneous malignancies arising from the diffuse neuroendocrine system. They frequently originate in the gastroenteropancreatic (GEP) tract and the ...bronchopulmonary tree, and their incidence has steadily increased in the last 3 decades. Fundamental biologic and genomic differences underlie the clinical heterogeneity of NETs, and distinct molecular features characterize NETs of different grades and different primary sites. Although surgery remains the cornerstone of treatment for localized tumors, systemic treatment options for patients with metastatic NETs have expanded considerably. Somatostatin analogs have demonstrated both antisecretory and antitumor efficacy. Peptide receptor radionuclide therapy with lutetium‐177 dotatate (177Lu‐DOTATATE) has been approved for advanced GEP‐NETs. The antitumor activity of everolimus has been demonstrated across a wide spectrum of NETs, and the antiangiogenic agent sunitinib has been approved for pancreatic NETs (pNETs). Chemotherapy with temozolomide and capecitabine has recently demonstrated an unprecedented prolongation of progression‐free survival in a randomized trial of pNETs. Multiple retrospective series have reported the efficacy of liver‐directed therapies both for palliating symptoms of hormone excess and for controlling tumor growth. Telotristat, an oral inhibitor of tryptophan hydroxylase, has been shown to reduce diarrhea in patients with carcinoid syndrome. Defining the therapeutic algorithm and identifying biomarkers predictive of response to treatments are among the main priorities for the next decade of research in the NET field.
Neuroendocrine neoplasms (NENs) arise from the diffuse neuroendocrine cell system and may occur at many different disease sites. Most frequently, these neoplasms occur in the digestive system, ...followed by the lung. The term NEN encompasses well-differentiated neuroendocrine tumours (NETs) and poorly differentiated neuroendocrine carcinomas (NECs). NECs represent only 10%–20% of all NENs. The main focus of these guidelines is on sporadic small intestinal (SI)-NENs and pancreatic NENs (Pan-NENs) since these are the most prevalent NENs at advanced disease stages. In general, the management of other gastrointestinal NENs follows the same principles as in SI- or Pan-NENs taking into consideration key features of NENs such as proliferative activity, somatostatin receptor (SSTR) expression, tumour growth rate and extent of the disease.
Abstract
GMrepo (data repository for Gut Microbiota) is a database of curated and consistently annotated human gut metagenomes. Its main purposes are to increase the reusability and accessibility of ...human gut metagenomic data, and enable cross-project and phenotype comparisons. To achieve these goals, we performed manual curation on the meta-data and organized the datasets in a phenotype-centric manner. GMrepo v2 contains 353 projects and 71,642 runs/samples, which are significantly increased from the previous version. Among these runs/samples, 45,111 and 26,531 were obtained by 16S rRNA amplicon and whole-genome metagenomics sequencing, respectively. We also increased the number of phenotypes from 92 to 133. In addition, we introduced disease-marker identification and cross-project/phenotype comparison. We first identified disease markers between two phenotypes (e.g. health versus diseases) on a per-project basis for selected projects. We then compared the identified markers for each phenotype pair across datasets to facilitate the identification of consistent microbial markers across datasets. Finally, we provided a marker-centric view to allow users to check if a marker has different trends in different diseases. So far, GMrepo includes 592 marker taxa (350 species and 242 genera) for 47 phenotype pairs, identified from 83 selected projects. GMrepo v2 is freely available at: https://gmrepo.humangut.info.
Inflammatory bowel diseases (IBD) affect over 5 million individuals in the industrialized world, with an increasing incidence rate worldwide. IBD also predisposes affected individuals to development ...of colorectal cancer, which is a leading cause of cancer-related deaths in adults. Mutations in genes encoding molecules in the IL-33 signaling pathway are associated with colitis and colitis-associated cancer (CAC), but how IL-33 modulates gut homeostasis is unclear. Here, we have shown that Il33-deficient mice are highly susceptible to colitis and CAC. Mechanistically, we observed that IL-33 promoted IgA production from B cells, which is important for maintaining microbial homeostasis in the intestine. Il33-deficient mice developed a dysbiotic microbiota that was characterized by increased levels of mucolytic and colitogenic bacteria. In response to chemically induced colitis, this microbial landscape promoted the release of IL-1α, which acted as a critical driver of colitis and CAC. Consequently, reconstitution of symbiotic microbiota or IL-1α ablation markedly ameliorated colitis susceptibility in Il33-deficient animals. Our results demonstrate that IL-33 promotes IgA production to maintain gut microbial homoeostasis and restrain IL-1α-dependent colitis and CAC. This study therefore highlights modulation of IL-33, IgA, IL-1α, and the microbiota as a potential therapeutic approach in the treatment of IBD and CAC.
Inflammation is increasingly recognized as an important component of tumorigenesis, although the mechanisms and pathways involved are not well understood. Tumor development is regulated by products ...of several modifier genes, but instructions for their tumor-specific expression are currently unknown. We show that the signaling through the adaptor protein MyD88 has a critical role in spontaneous tumor development in mice with heterozygous mutation in the adenomatous polyposis coli (APC) gene. We found that MyD88-dependent signaling controls the expression of several key modifier genes of intestinal tumorigenesis and has a critical role in both spontaneous and carcinogen-induced tumor development. This study thus reveals the important role of an innate immune signaling pathway in intestinal tumorigenesis.
Peptide receptor radionuclide therapy (PRRT) is an established treatment of metastatic neuroendocrine tumors grade 1-2 (G1-G2). However, its possible benefit in high-grade gastroenteropancreatic ...(GEP) neuroendocrine neoplasms (NEN G3) is largely unknown. We therefore aimed to assess the benefits and side effects of PRRT in patients with GEP NEN G3. We performed a retrospective cohort study at 12 centers to assess the efficacy and toxicity of PRRT in patients with GEP NEN G3. Outcomes were response rate, disease control rate, progression-free survival (PFS), overall survival (OS) and toxicity. We included 149 patients (primary tumor: pancreatic n = 89, gastrointestinal n = 34, unknown n = 26). PRRT was first-line (n = 30), second-line (n = 62) or later-line treatment (n = 57). Of 114 patients evaluated, 1% had complete response, 41% partial response, 38% stable disease and 20% progressive disease. Of 104 patients with documented progressive disease before PRRT, disease control rate was 69%. The total cohort had median PFS of 14 months and OS of 29 months. Ki-67 21-54% (n = 125) vs Ki-67 ≥55% (n = 23): PFS 16 vs 6 months (P < 0.001) and OS 31 vs 9 months (P < 0.001). Well (n = 60) vs poorly differentiated NEN (n = 62): PFS 19 vs 8 months (P < 0.001) and OS 44 vs 19 months (P < 0.001). Grade 3-4 hematological or renal toxicity occurred in 17% of patients. This large multicenter cohort of patients with GEP NEN G3 treated with PRRT demonstrates promising response rates, disease control rates, PFS and OS as well as toxicity in patients with mainly progressive disease. Based on these results, PRRT may be considered for patients with GEP NEN G3.
The traditionally promulgated perspectives of neuroendocrine neoplasms (NEN) as rare, indolent tumours are blunt and have been outdated for the last 2 decades. Clear increments in their incidence ...over the past decades render them increasingly clinically relevant, and at initial diagnosis many present with nodal and/or distant metastases (notably hepatic). The molecular pathogenesis of these tumours is increasingly yet incompletely understood. Those arising from the small bowel (SB) or pancreas typically occur sporadically; the latter may occur within the context of hereditary tumour predisposition syndromes. NENs can also be associated with endocrinopathy of hormonal hypersecretion. Tangible advances in the development of novel biomarkers, functional imaging modalities and therapy are especially applicable to this sub-set of tumours. The management of SB and pancreatic neuroendocrine tumours (NET) may be challenging, and often comprises a multidisciplinary approach wherein surgical, medical, interventional radiological and radiotherapeutic modalities are implemented. This review provides a comprehensive overview of the epidemiology, pathophysiology, diagnosis and treatment of SB and pancreatic NETs. Moreover, we provide an outlook of the future in these tumour types which will include the development of precision oncology frameworks for individualised therapy, multi-analyte predictive biomarkers, artificial intelligence-derived clinical decision support tools and elucidation of the role of the microbiome in NEN development and clinical behaviour.
PDF
