bims-instec 2023-04-09 papers

bims-instec

Biomed News

on Intestinal stem cells and chemoresistance in colon cancer and intestinal regeneration

Issue of 2023–04–09
eightteen papers selected by
Maria-Virginia Giolito, Free University of Brussels

Graded BMP signaling within intestinal crypt architecture directs self-organization of the Wnt-secreting stem cell niche.
Platform combining statistical modeling and patient-derived organoids to facilitate personalized treatment of colorectal carcinoma.
Segregation of the stemness program from the proliferation program in intestinal stem cells.
The intestinal stem cell niche flexes its muscles.
Genetic heterogeneity of colorectal cancer and the microbiome.
Oncogenic signaling is coupled to colorectal cancer cell differentiation state.
The v8-10 variant isoform of CD44 is selectively expressed in the normal human colonic stem cell niche and frequently is overexpressed in colon carcinomas during tumor development.
Mutations linked to chemotherapy resistance in colorectal cancer.
Mitophagy-related gene signature predicts prognosis, immune infiltration and chemotherapy sensitivity in colorectal cancer.
RBM47 regulates intestinal injury and tumorigenesis by modifying proliferation, oxidative response and inflammatory pathways.
Early weaning causes small intestinal atrophy by inhibiting the activity of intestinal stem cells: involvement of Wnt/β-catenin signaling.
Role of stemness-related genes TIMP1, PGF, and SNAI1 in the prognosis of colorectal cancer through single-cell RNA-seq.
DR3 regulates intestinal epithelial homeostasis and regeneration after intestinal barrier injury.
RAF1 contributes to cell proliferation and STAT3 activation in colorectal cancer independently of microsatellite and KRAS status.
Phase separation of DDX21 promotes colorectal cancer metastasis via MCM5-dependent EMT pathway.
A novel tumour enhancer function of Insulin-like growth factor II mRNA-binding protein 3 in colorectal cancer.
Sex and gender perspectives in colorectal cancer.
Maintenance of high-turnover tissues during and beyond homeostasis.

Cell Stem Cell. 2023 Apr 06. pii: S1934-5909(23)00075-9. [Epub ahead of print]30(4): 433-449.e8

Graded BMP signaling within intestinal crypt architecture directs self-organization of the Wnt-secreting stem cell niche.

Judith Kraiczy, Neil McCarthy, Ermanno Malagola, Guodong Tie, Shariq Madha, Dario Boffelli, Daniel E Wagner, Timothy C Wang, Ramesh A Shivdasani.

  Signals from the surrounding niche drive proliferation and suppress differentiation of intestinal stem cells (ISCs) at the bottom of intestinal crypts. Among sub-epithelial support cells, deep sub-cryptal CD81+ PDGFRAlo trophocytes capably sustain ISC functions ex vivo. Here, we show that mRNA and chromatin profiles of abundant CD81- PDGFRAlo mouse stromal cells resemble those of trophocytes and that both populations provide crucial canonical Wnt ligands. Mesenchymal expression of key ISC-supportive factors extends along a spatial and molecular continuum from trophocytes into peri-cryptal CD81- CD55hi cells, which mimic trophocyte activity in organoid co-cultures. Graded expression of essential niche factors is not cell-autonomous but dictated by the distance from bone morphogenetic protein (BMP)-secreting PDGFRAhi myofibroblast aggregates. BMP signaling inhibits ISC-trophic genes in PDGFRAlo cells near high crypt tiers; that suppression is relieved in stromal cells near and below the crypt base, including trophocytes. Cell distances thus underlie a self-organized and polar ISC niche.

Keywords:  PDGFRA+ mesenchymal cells; colonic crypts; intestinal Wnt source; intestinal crypt structure and function; intestinal stem cell niche; mesenchymal niche compartments; trophocytes

DOI:  https://doi.org/10.1016/j.stem.2023.03.004
J Exp Clin Cancer Res. 2023 Apr 03. 42(1): 79

Platform combining statistical modeling and patient-derived organoids to facilitate personalized treatment of colorectal carcinoma.

George M Ramzy, Maxim Norkin, Thibaud Koessler, Lionel Voirol, Mathieu Tihy, Dina Hany, Thomas McKee, Frédéric Ris, Nicolas Buchs, Mylène Docquier, Christian Toso, Laura Rubbia-Brandt, Gaetan Bakalli, Stéphane Guerrier, Joerg Huelsken, Patrycja Nowak-Sliwinska.

   BACKGROUND: We propose a new approach for designing personalized treatment for colorectal cancer (CRC) patients, by combining ex vivo organoid efficacy testing with mathematical modeling of the results.
METHODS: The validated phenotypic approach called Therapeutically Guided Multidrug Optimization (TGMO) was used to identify four low-dose synergistic optimized drug combinations (ODC) in 3D human CRC models of cells that are either sensitive or resistant to first-line CRC chemotherapy (FOLFOXIRI). Our findings were obtained using second order linear regression and adaptive lasso.
RESULTS: The activity of all ODCs was validated on patient-derived organoids (PDO) from cases with either primary or metastatic CRC. The CRC material was molecularly characterized using whole-exome sequencing and RNAseq. In PDO from patients with liver metastases (stage IV) identified as CMS4/CRIS-A, our ODCs consisting of regorafenib [1 mM], vemurafenib [11 mM], palbociclib [1 mM] and lapatinib [0.5 mM] inhibited cell viability up to 88%, which significantly outperforms FOLFOXIRI administered at clinical doses. Furthermore, we identified patient-specific TGMO-based ODCs that outperform the efficacy of the current chemotherapy standard of care, FOLFOXIRI.
CONCLUSIONS: Our approach allows the optimization of patient-tailored synergistic multi-drug combinations within a clinically relevant timeframe.

Keywords:  Drug resistance; Drug-drug interaction; Multidrug combination; Organoid; Phenotypic screen; Synergy; Targeted RNAseq

DOI:  https://doi.org/10.1186/s13046-023-02650-z
Stem Cell Reports. 2023 Mar 24. pii: S2213-6711(23)00095-4. [Epub ahead of print]

Segregation of the stemness program from the proliferation program in intestinal stem cells.

Yuan Liu, Meimei Huang, Xiaodan Wang, Zinan Liu, Siqi Li, Ye-Guang Chen.

  Stem cells can undergo continuous self-renewal and meanwhile retain the stemness capability to differentiate to mature functional cells. However, it is unclear whether the proliferation property can be segregated from the stemness in stem cells. The intestinal epithelium undergoes fast renewal, and the Lgr5+ intestinal stem cells (ISCs) are essential to maintain homeostasis. Here, we report that methyltransferase-like 3 (Mettl3), a critical enzyme for N6-methyladenosine (m6A) methylation, is required for ISCs maintenance as its deletion results in fast loss of stemness markers but has no effect on cell proliferation. We further identify four m6A-modified transcriptional factors, whose ectopic expression can restore stemness gene expression in Mettl3-/- organoids, while their silencing leads to stemness loss. In addition, transcriptomic profiling analysis discerns 23 genes that can be segregated from the genes responsible for cell proliferation. Together, these data reveal that m6A modification sustains ISC stemness, which can be uncoupled from cell proliferation.

Keywords:  Lgr5; Mettl3; intestinal stem cells; m6A modification; proliferation; stemness

DOI:  https://doi.org/10.1016/j.stemcr.2023.03.007
Nat Rev Mol Cell Biol. 2023 Apr 05.

The intestinal stem cell niche flexes its muscles.

Lisa Heinke.

DOI: https://doi.org/10.1038/s41580-023-00605-y
World J Gastrointest Oncol. 2023 Mar 15. 15(3): 443-463

Genetic heterogeneity of colorectal cancer and the microbiome.

Marina A Senchukova.

  In 2020, the International Agency for Research on Cancer and the World Health Organization's GLOBOCAN database ranked colorectal cancer (CRC) as the third most common cancer in the world. Most cases of CRC (> 95%) are sporadic and develop from colorectal polyps that can progress to intramucosal carcinoma and CRC. Increasing evidence is accumulating that the gut microbiota can play a key role in the initiation and progression of CRC, as well as in the treatment of CRC, acting as an important metabolic and immunological regulator. Factors that may determine the microbiota role in CRC carcinogenesis include inflammation, changes in intestinal stem cell function, impact of bacterial metabolites on gut mucosa, accumulation of genetic mutations and other factors. In this review, I discuss the major mechanisms of the development of sporadic CRC, provide detailed characteristics of the bacteria that are most often associated with CRC, and analyze the role of the microbiome and microbial metabolites in inflammation initiation, activation of proliferative activity in intestinal epithelial and stem cells, and the development of genetic and epigenetic changes in CRC. I consider long-term studies in this direction to be very important, as they open up new opportunities for the treatment and prevention of CRC.

Keywords:  Bacterial metabolites; Colorectal cancer; Colorectal polyp; Epigenetic changes; Gut microbiota; Stem cells

DOI:  https://doi.org/10.4251/wjgo.v15.i3.443
J Cell Biol. 2023 Jun 05. pii: e202204001. [Epub ahead of print]222(6):

Oncogenic signaling is coupled to colorectal cancer cell differentiation state.

Thomas Sell, Christian Klotz, Matthias M Fischer, Rosario Astaburuaga-García, Susanne Krug, Jarno Drost, Hans Clevers, Christine Sers, Markus Morkel, Nils Blüthgen.

Colorectal cancer progression is intrinsically linked to stepwise deregulation of the intestinal differentiation trajectory. In this process, sequential mutations of APC, KRAS, TP53, and SMAD4 enable oncogenic signaling and establish the hallmarks of cancer. Here, we use mass cytometry of isogenic human colon organoids and patient-derived cancer organoids to capture oncogenic signaling, cell phenotypes, and differentiation states in a high-dimensional single-cell map. We define a differentiation axis in all tumor progression states from normal to cancer. Our data show that colorectal cancer driver mutations shape the distribution of cells along the differentiation axis. In this regard, subsequent mutations can have stem cell promoting or restricting effects. Individual nodes of the cancer cell signaling network remain coupled to the differentiation state, regardless of the presence of driver mutations. We use single-cell RNA sequencing to link the (phospho-)protein signaling network to transcriptomic states with biological and clinical relevance. Our work highlights how oncogenes gradually shape signaling and transcriptomes during tumor progression.

DOI: https://doi.org/10.1083/jcb.202204001
Cancer Biol Ther. 2023 Dec 31. 24(1): 2195363

The v8-10 variant isoform of CD44 is selectively expressed in the normal human colonic stem cell niche and frequently is overexpressed in colon carcinomas during tumor development.

Bruce M Boman, Vignesh Viswanathan, Caroline O B Facey, Jeremy Z Fields, James W Stave.

  CD44 protein and its variant isoforms are expressed in cancer stem cells (CSCs), and various CD44 isoforms can have different functional roles in cells. Our goal was to investigate how different CD44 isoforms contribute to the emergence of stem cell (SC) overpopulation that drives colorectal cancer (CRC) development. Specific CD44 variant isoforms are selectively expressed in normal colonic SCs and become overexpressed in CRCs during tumor development. We created a unique panel of anti-CD44 rabbit genomic antibodies to 16 specific epitopes that span the entire length of the CD44 molecule. Our panel was used to comprehensively investigate the expression of different CD44 isoforms in matched pairs (n = 10) of malignant colonic tissue and adjacent normal mucosa, using two (IHC & IF) immunostaining approaches. We found that: i) CD44v8-10 is selectively expressed in the normal human colonic SC niche; ii) CD44v8-10 is co-expressed with the SC markers ALDH1 and LGR5 in normal and malignant colon tissues; iii) colon carcinoma tissues frequently (80%) stain for CD44v8-10 while staining for CD44v6 was less frequent (40%). Given that CD44v8-10 expression is restricted to cells in the normal human colonic SC niche and CD44v8-10 expression progressively increases during CRC development, CD44v8-10 expression likely contributes to the SC overpopulation that drives the development and growth of colon cancers. Since the CD44 variant v8-10 epitope is located on CD44's extracellular region, it offers great promise for targeted anti-CSC treatment approaches.

Keywords:  CD44 protein; CD44 variant isoforms; CD44v8-10; cancer stem cells; colorectal cancer

DOI:  https://doi.org/10.1080/15384047.2023.2195363
Nat Rev Gastroenterol Hepatol. 2023 Apr 03.

Mutations linked to chemotherapy resistance in colorectal cancer.

Ian Fyfe.

DOI: https://doi.org/10.1038/s41575-023-00772-5
World J Gastrointest Oncol. 2023 Mar 15. 15(3): 546-561

Mitophagy-related gene signature predicts prognosis, immune infiltration and chemotherapy sensitivity in colorectal cancer.

Jin-Sen Weng, Jie-Ping Huang, Wei Yu, Jun Xiao, Fang Lin, Kang-Ni Lin, Wei-Dong Zang, Yong Ye, Jing-Ping Lin.

   BACKGROUND: Mitophagy plays essential role in the development and progression of colorectal cancer (CRC). However, the effect of mitophagy-related genes in CRC remains largely unknown.
AIM: To develop a mitophagy-related gene signature to predict the survival, immune infiltration and chemotherapy response of CRC patients.
METHODS: Non-negative matrix factorization was used to cluster CRC patients from Gene Expression Omnibus database (GSE39582, GSE17536, and GSE37892) based on mitophagy-related gene expression. The CIBERSORT method was applied for the evaluation of the relative infiltration levels of immune cell types. The performance signature in predicting chemotherapeutic sensitivity was generated using data from the Genomics of Drug Sensitivity in Cancer database.
RESULTS: Three clusters with different clinicopathological features and prognosis were identified. Higher enrichment of activated B cells and CD4+ T cells were observed in cluster III patients with the most favorable prognosis. Next, a risk model based on mitophagy-related genes was developed. Patients in training and validation sets were categorized into low-risk and high-risk subgroups. Low risk patients showed significantly better prognosis, higher enrichment of immune activating cells and greater response to chemotherapy (oxaliplatin, irinotecan, and 5-fluorouracil) compared to high-risk patients. Further experiments identified CXCL3 as novel regulator of cell proliferation and mitophagy.
CONCLUSION: We revealed the biological roles of mitophagy-related genes in the immune infiltration, and its ability to predict patients' prognosis and response to chemotherapy in CRC. These interesting findings would provide new insight into the therapeutic management of CRC patients.

Keywords:  Colorectal cancer; Immunotherapy; Mitophagy; Prognosis; Tumor microenvironment

DOI:  https://doi.org/10.4251/wjgo.v15.i3.546
JCI Insight. 2023 Apr 04. pii: e161118. [Epub ahead of print]

RBM47 regulates intestinal injury and tumorigenesis by modifying proliferation, oxidative response and inflammatory pathways.

Saeed Soleymanjahi, Valerie Blanc, Elizabeth A Molitor, David M Alvarado, Yan Xie, Vered Gazit, Jeffrey W Brown, Kathleen Byrnes, Ta-Chiang Liu, Jason C Mills, Matthew A Ciorba, Deborah C Rubin, Nicholas O Davidson.

   RATIONALE: RNA binding protein 47 (RBM47) is required for embryonic endoderm development but a role in adult intestine is unknown.
OBJECTIVE: We studied intestine-specific Rbm47 knockout mice (Rbm47-IKO) following intestinal injury and made crosses into Apcmin/+ mice to examine alterations in intestinal proliferation, response to injury and tumorigenesis. We also interrogated human colorectal polyps and colon carcinoma tissue.
FINDINGS: Rbm47-IKO mice exhibit increased proliferation, abnormal villus morphology and cellularity, with corresponding changes in Rbm47-IKO organoids. Rbm47-IKO mice adapt to radiation injury and are protected against chemical-induced colitis, with Rbm47-IKO intestine showing upregulation of antioxidant and Wnt signaling pathways as well as stem cell and developmental genes. Furthermore, Rbm47-IKO mice are protected against colitis-associated cancer. By contrast, aged Rbm47-IKO mice develop spontaneous polyposis and Rbm47-IKO, Apcmin/+ mice manifest an increased intestinal polyp burden. RBM47 mRNA was decreased in human colorectal cancer versus paired normal tissue along with alternative splicing of TJP1 mRNA. Public databases revealed stage-specific reduction in RBM47 expression in colorectal cancer, associated independently with decreased overall survival.
CONCLUSIONS: These findings implicate RBM47 as a cell-intrinsic modifier of intestinal growth, inflammatory and tumorigenic pathways.

Keywords:  Colorectal cancer; Gastroenterology; Inflammation; RNA processing

DOI:  https://doi.org/10.1172/jci.insight.161118
Stem Cell Res Ther. 2023 Apr 05. 14(1): 65

Early weaning causes small intestinal atrophy by inhibiting the activity of intestinal stem cells: involvement of Wnt/β-catenin signaling.

Junquan Tian, Yuying Li, Xuetai Bao, Fan Yang, Xiongzhuo Tang, Qian Jiang, Yulong Yin, Kang Yao.

   BACKGROUND: Early weaning and shorter breastfeeding duration are applied by a proportion of young mothers, especially in the social spheres of poverty-stricken areas. Early childhood is a critical period for intestinal development, which is driven by intestinal stem cells (ISCs). However, how early weaning practice affects the function of ISCs to mediate intestinal development remains unclear.
METHODS: We established an excellent early weaning mice model that has significant intestinal atrophy and growth arrest symptoms to explore the responses of ISCs to early weaning. The primary and passaged intestinal organoids from the suckling or early weaning mice were cultured to explore the underlying mechanism of early weaning affecting the ISCs.
RESULTS: Early weaning depressed the self-renewal of ISCs and attenuated the activity of ISCs-driven intestinal epithelial regeneration and crypt expansion in vivo and ex-vivo. Further results showed that early weaning retarded the differentiation of ISCs into transit-amplifying cells and Paneth cells, and accelerated the apoptosis of villous epithelial cells, jointly leading to intestinal epithelial atrophy. Mechanistically, early weaning inhibited Wnt signaling in ISCs, while an exogenous Wnt amplifier restored ISCs' function in ex-vivo.
CONCLUSION: Our findings indicate that early weaning depresses the activity of ISCs via attenuating Wnt/β-catenin signaling and triggers the proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-17 in jejunum, thereby impeding ISCs-driven epithelial regeneration and intestinal growth, which may provide a basal theory for the development of infant nutrients targeting stem cells to alleviate early weaning-induced intestinal problems.

Keywords:  Early weaning; Epithelial regeneration; Intestinal growth; Intestinal stem cells; Wnt/β-catenin

DOI:  https://doi.org/10.1186/s13287-023-03293-9
Cancer Med. 2023 Apr 05.

Role of stemness-related genes TIMP1, PGF, and SNAI1 in the prognosis of colorectal cancer through single-cell RNA-seq.

Yan Shen, Siyi Ni, Si Li, Bin Lv.

   BACKGROUND: Colorectal cancer (CRC) is a fatal malignant tumor with poor prognosis. Cancer stem cells (CSCs) can cause metastasis, recurrence and drug resistance in CRC. This research aimed to analyze stemness-related prognostic genes of CRC based on single-cell RNA-sequencing (scRNA-seq) data.
METHODS: DESeq2 was applied to analyze the differentially expressed genes (DEGs). The mRNA stemness index (mRNAsi) was calculated by one-class logistic regression (OCLR). The stemness-related cells were analyzed based on scRNA-seq dataset GSE166555. Monocle 2 algorithm was used for stemness-related cells pseudotime trajectory analysis. The stemness-related prognostic genes were analyzed by clusterProfiler and survival package. The stemness of CRC cells was detected by spheroid formation assay, and the expression of stemness-related prognostic genes was verified by qRT-PCR and Western blot.
RESULTS: 7916 DEGs between the CRC and normal tissues were obtained. The mRNAsi of the CRC tissues was shown to be significantly higher than that of the normal tissues. 7 and 8 cell types were annotated respectively in the normal and CRC tissues through analysis of the scRNA-seq data. Cell-cell interactions (CCIs) in the tumor tissues were revealed to be significantly enhanced than that in the normal tissues. By calculating the 'stemness score', CSCs, epithelial cells (EPCs) and cancer-associated fibroblasts (CAFs) were defined as stemness-related cells. Through pseudotime trajectory analysis, 2111 genes were identified as state 2-specific genes. Then, 41 genes were obtained by taking intersection of the up-regulated genes with state 2-specific genes and marker genes of CSCs, EPCs and CAFs. The univariate COX regression analysis revealed 5 stemness-related prognostic genes (TIMP1, PGF, FSTL3, SNAI1 and FOXC1). Kaplan-Meier curve analysis indicated that the higher the expression of 5 genes, the lower the survival rate. In vitro cell experiment confirmed that the expression of TIMP1, PGF and SNAI1 was consistent with that revealed by bioinformatics analysis.
CONCLUSIONS: TIMP1, PGF and SNAI1 were identified as stemness-related prognostic genes of CRC, and possibly potential therapeutic targets for CRC.

Keywords:  colorectal cancer; in vitro cell experiment; pseudotime trajectories analysis; single-cell RNA-seq; stemness-related prognostic genes

DOI:  https://doi.org/10.1002/cam4.5833
Cell Mol Gastroenterol Hepatol. 2023 Apr 01. pii: S2352-345X(23)00048-6. [Epub ahead of print]

DR3 regulates intestinal epithelial homeostasis and regeneration after intestinal barrier injury.

Yosuke Shimodaira, Shyam K More, Hussein Hamade, Anna Y Blackwood, Jay P Abraham, Lisa S Thomas, Jordan H Miller, Dalton T Stamps, Sofi L Castanon, Noam Jacob, Connie W Y Ha, Suzanne Devkota, David Q Shih, Stephan R Targan, Kathrin S Michelsen.

   BACKGROUND & AIMS: TNF superfamily member TL1A has been associated with susceptibility and severity of inflammatory bowel diseases. However, the function of TL1A and its receptor DR3 in the development of intestinal inflammation is incompletely understood. We investigated the role of DR3 expressed by intestinal epithelial cells (IEC) during intestinal homeostasis, tissue injury, and regeneration.
METHODS: Clinical phenotype and histological inflammation were assessed in C57BL/6 (WT), Tl1a-/-, and Dr3-/- mice in dextran sulfate sodium (DSS)-induced colitis. We generated mice with an IEC-specific deletion of DR3 (Dr3ΔIEC) and assessed intestinal inflammation and epithelial barrier repair. In vivo intestinal permeability was assessed by Fluorescein isothiocyanate dextran uptake. Proliferation of IEC was analyzed by Bromodeoxyuridine incorporation. Expression of DR3 mRNA was assessed by fluorescent in situ hybridization. Small intestinal organoids were used to determine ex vivo regenerative potential.
RESULTS: Dr3-/- mice developed more severe colonic inflammation than WT mice in DSS-induced colitis with significantly impaired IEC regeneration. Homeostatic proliferation of IEC was increased in Dr3-/- mice but blunted during regeneration. Cellular localization and expression of the tight junction proteins Claudin-1 and zonula occudens-1 (ZO-1) was altered leading to increased homeostatic intestinal permeability. Dr3ΔIEC mice recapitulated the phenotype observed in Dr3-/- mice with increased intestinal permeability and IEC proliferation under homeostatic condition and impaired tissue repair and increased bacterial translocation during DSS-induced colitis. Impaired regenerative potential and altered ZO-1 localization was also observed in Dr3ΔIEC enteroids.
CONCLUSIONS: Our findings establish a novel function of DR3 in IEC homeostasis and post-injury regeneration independent of its established role in innate lymphoid cells and T helper cells.

Keywords:  Epithelial barrier; IEC proliferation; Intestinal Permeability; tissue regeneration

DOI:  https://doi.org/10.1016/j.jcmgh.2023.03.008
Oncogene. 2023 Apr 05.

RAF1 contributes to cell proliferation and STAT3 activation in colorectal cancer independently of microsatellite and KRAS status.

Coralie Dorard, Claire Madry, Olivier Buhard, Stefanie Toifl, Sebastian Didusch, Toky Ratovomanana, Quentin Letourneur, Helmut Dolznig, Mathew J Garnett, Alex Duval, Manuela Baccarini.

More than 30% of all human cancers are driven by RAS mutations and activating KRAS mutations are present in 40% of colorectal cancer (CRC) in the two main CRC subgroups, MSS (Microsatellite Stable) and MSI (Microsatellite Instable). Studies in RAS-driven tumors have shown essential roles of the RAS effectors RAF and specifically of RAF1, which can be dependent or independent of RAF's ability to activate the MEK/ERK module. In this study, we demonstrate that RAF1, but not its kinase activity, plays a crucial role in the proliferation of both MSI and MSS CRC cell line-derived spheroids and patient-derived organoids, and independently of KRAS mutation status. Moreover, we could define a RAF1 transcriptomic signature which includes genes that contribute to STAT3 activation, and could demonstrate that RAF1 ablation decreases STAT3 phosphorylation in all CRC spheroids tested. The genes involved in STAT3 activation as well as STAT3 targets promoting angiogenesis were also downregulated in human primary tumors expressing low levels of RAF1. These results indicate that RAF1 could be an attractive therapeutic target in both MSI and MSS CRC regardless of their KRAS status and support the development of selective RAF1 degraders rather than RAF1 inhibitors for clinical use in combination therapies.

DOI: https://doi.org/10.1038/s41388-023-02683-w
Oncogene. 2023 Apr 07.

Phase separation of DDX21 promotes colorectal cancer metastasis via MCM5-dependent EMT pathway.

Huabin Gao, Huiting Wei, Yang Yang, Hui Li, Jiangtao Liang, Jiecheng Ye, Fenfen Zhang, Liyuan Wang, Huijuan Shi, Jia Wang, Anjia Han.

RNA binding proteins (RBPs) contributes to cancer progression, but the underlying mechanism reminds unclear. Here, we find that DDX21, a representative RBP, is highly expressed in colorectal cancer (CRC), which leads to CRC cell migration and invasion in vitro, and CRC to liver metastasis and lung metastasis in vivo. This effect of DDX21 on CRC metastasis is correlated to the activation of Epithelial-mesenchymal transition (EMT) pathway. Moreover, we reveal that DDX21 protein is phase separated in vitro and in CRC cells, which controls CRC metastasis. Phase-separated DDX21 highly binds on MCM5 gene locus, which is markedly reduced when phase separation is disrupted by mutations on its intrinsically disordered region (IDR). The impaired metastatic ability of CRC upon DDX21 loss is restored by ectopic expression of MCM5, indicating MCM5 is a key downstream target of DDX21 for CRC metastasis. Furthermore, co-higher expressions of DDX21 and MCM5 is significantly correlated with poor survival outcomes of stage III and IV CRC patients, indicating the importance of this mechanism in CRC late and metastatic stage. Altogether, our results elucidate a new model of DDX21 in regulating CRC metastasis via phase separation.

DOI: https://doi.org/10.1038/s41388-023-02687-6
Cell Death Dis. 2023 Apr 06. 14(4): 243

A novel tumour enhancer function of Insulin-like growth factor II mRNA-binding protein 3 in colorectal cancer.

Davide Di Fusco, Antonio Di Grazia, Giulia Di Maggio, Maria Teresa Segreto, Andrea Iannucci, Claudia Maresca, Alessandro De Stefano, Giuseppe Sica, Carmine Stolfi, Giovanni Monteleone, Ivan Monteleone.

CRC cells evolve a variety of strategies to limit or circumvent apoptosis cell death. RNA binding proteins (RBPs) regulate many of the molecular mechanisms that underlie the development of cancer. The insulin-like growth factor II mRNA-binding proteins (IMP) family are oncofoetal RBPs, consisting of IMP1, IMP2 and IMP3, which have an important role in RNA metabolism. IMP3 is highly expressed in colorectal cancer (CRC) tissue, where its expression often correlates with poor prognosis. However, the role of IMP3 in CRC is not fully understood. IMP3 expression was analysed using a public database and by Western blotting and immunohistochemistry in human colon samples derived from patients with sporadic CRC and healthy subjects. To address whether IMP3 controls cancer cell survival, we analysed cell death pathways in in vitro and in vivo experiments after IMP3 downregulation by siRNA or an antisense oligonucleotide. IMP3 was highly expressed in CRC samples compared to normal control tissues. The knockdown of IMP3 enhanced a caspase-independent cell death in CRC cell lines. Furthermore, the treatment of CRC cells with IMP3 siRNA did not alter the expression of GSDMD, GPX-4 and the activated form of RIP3, three key molecules that govern pyroptosis, ferroptosis and necroptosis, respectively. Abrogation of IMP3 in CRC significantly reduced Bcl-2 and Bcl-xL mRNA and was associated with an altered mitochondrial membrane potential that allowed the nuclear migration of the apoptosis-inducing factor (AIF). Moreover, specific immunoprecipitation experiments on CRC human cell lines indicated that IMP3 binds Bcl-2 and Bcl-xL mRNA, suggesting that IMP3 acts as a regulator of the intrinsic apoptotic pathway through the surveillance of anti-apoptotic Bcl mRNA metabolism. Finally, we showed that IMP3 block inhibited the growth of CRC cell lines in vivo after transplantation into immunodeficient mice. Altogether, these data support a novel role for IMP3 in controlling the intrinsic caspase-independent apoptotic pathway in CRC.

DOI: https://doi.org/10.1038/s41419-023-05772-6
ESMO Open. 2023 Mar 31. pii: S2059-7029(23)00427-1. [Epub ahead of print]8(2): 101204

Sex and gender perspectives in colorectal cancer.

I Baraibar, J Ros, N Saoudi, F Salvà, A García, M R Castells, J Tabernero, E Élez.

  Historically women were frequently excluded from clinical trials and drug usage to protect unborn babies from potential harm. As a consequence, the impact of sex and gender on both tumour biology and clinical outcomes has been largely underestimated. Although interrelated and often used interchangeably, sex and gender are not equivalent concepts. Sex is a biological attribute that defines species according to their chromosomal makeup and reproductive organ, while gender refers to a chosen sexual identity. Sex dimorphisms are rarely taken into account, in either preclinical or clinical research, with inadequate analysis of differences in outcomes according to sex or gender still widespread, reflecting a gap in our knowledge for a large proportion of the target population. Underestimation of sex-based differences in study design and analyses has invariably led to 'one-drug' treatment regimens for both males and females. For patients with colorectal cancer (CRC), sex also has an impact on the disease incidence, clinicopathological features, therapeutic outcomes, and tolerability to anticancer treatments. Although the global incidence of CRC is higher in male subjects, the proportion of patients presenting right-sided tumours and BRAF mutations is higher among females. Concerning sex-related differences in treatment efficacy and toxicity, drug dosage does not take into account sex-specific differences in pharmacokinetics. Toxicity associated with fluoropyrimidines, targeted therapies, and immunotherapies has been reported to be more extensive for females with CRC than for males, although evidence about differences in efficacy is more controversial. This article aims to provide an overview of the research achieved so far into sex and gender differences in cancer and summarize the growing body of literature illustrating the sex and gender perspective in CRC and their impact in relation to tumour biology and treatment efficacy and toxicity. We propose endorsing research on how biological sex and gender influence CRC as an added value for precision oncology.

Keywords:  colorectal cancer; gender; sex; toxicity; treatment; tumour biology

DOI:  https://doi.org/10.1016/j.esmoop.2023.101204
Cell Stem Cell. 2023 Apr 06. pii: S1934-5909(23)00079-6. [Epub ahead of print]30(4): 348-361

Maintenance of high-turnover tissues during and beyond homeostasis.

Isidora Banjac, Martti Maimets, Kim B Jensen.

Tissues with a high turnover rate produce millions of cells daily and have abundant regenerative capacity. At the core of their maintenance are populations of stem cells that balance self-renewal and differentiation to produce the adequate numbers of specialized cells required for carrying out essential tissue functions. Here, we compare and contrast the intricate mechanisms and elements of homeostasis and injury-driven regeneration in the epidermis, hematopoietic system, and intestinal epithelium-the fastest renewing tissues in mammals. We highlight the functional relevance of the main mechanisms and identify open questions in the field of tissue maintenance.

DOI: https://doi.org/10.1016/j.stem.2023.03.008