<i>BCL9L</i> dysfunction impairs caspase-2 expression permitting aneuploidy tolerance in colorectal cancer

Chromosomal instability (CIN) contributes to cancer evolution, intratumor heterogeneity, and drug resistance. CIN is driven by chromosome segregation errors and a tolerance phenotype that permits the propagation of aneuploid genomes. Through genomic analysis of colorectal cancers and cell lines, we find frequent loss of heterozygosity and mutations in BCL9L in aneuploid tumors. BCL9L deficiency promoted tolerance of chromosome missegregation events, propagation of aneuploidy, and genetic heterogeneity in xenograft models likely through modulation of Wnt signaling. We find that BCL9L dysfunction contributes to aneuploidy tolerance in both TP53-WT and mutant cells by reducing basal caspase-2 levels and preventing cleavage of MDM2 and BID. Efforts to exploit aneuploidy tolerance mechanisms and the BCL9L/caspase-2/BID axis may limit cancer diversity and evolution

Intrinsic Resistance to MEK Inhibition in KRAS Mutant Lung and Colon Cancer through Transcriptional Induction of ERBB3

Summary There are no effective therapies for the ∼30% of human malignancies with mutant RAS oncogenes. Using a kinome-centered synthetic lethality screen, we find that suppression of the ERBB3 receptor tyrosine kinase sensitizes KRAS mutant lung and colon cancer cells to MEK inhibitors. We show that MEK inhibition results in MYC-dependent transcriptional upregulation of ERBB3, which is responsible for intrinsic drug resistance. Drugs targeting both EGFR and ERBB2, each capable of forming heterodimers with ERBB3, can reverse unresponsiveness to MEK inhibition by decreasing inhibitory phosphorylation of the proapoptotic proteins BAD and BIM. Moreover, ERBB3 protein level is a biomarker of response to combinatorial treatment. These data suggest a combination strategy for treating KRAS mutant colon and lung cancers and a way to identify the tumors that are most likely to benefit from such combinatorial treatment

Selective inhibition of cancer cell self-renewal through a Quisinostat-histone H1.0 axis

Continuous cancer growth is driven by subsets of self-renewing malignant cells. Targeting of uncontrolled self-renewal through inhibition of stem cell-related signaling pathways has proven challenging. Here, we show that cancer cells can be selectively deprived of self-renewal ability by interfering with their epigenetic state. Re-expression of histone H1.0, a tumor-suppressive factor that inhibits cancer cell self-renewal in many cancer types, can be broadly induced by the clinically well-tolerated compound Quisinostat. Through H1.0, Quisinostat inhibits cancer cell self-renewal and halts tumor maintenance without affecting normal stem cell function. Quisinostat also hinders expansion of cells surviving targeted therapy, independently of the cancer types and the resistance mechanism, and inhibits disease relapse in mouse models of lung cancer. Our results identify H1.0 as a major mediator of Quisinostat's antitumor effect and suggest that sequential administration of targeted therapy and Quisinostat may be a broadly applicable strategy to induce a prolonged response in patients

Deterministic Evolutionary Trajectories Influence Primary Tumor Growth: TRACERx Renal.

The evolutionary features of clear-cell renal cell carcinoma (ccRCC) have not been systematically studied to date. We analyzed 1,206 primary tumor regions from 101 patients recruited into the multi-center prospective study, TRACERx Renal. We observe up to 30 driver events per tumor and show that subclonal diversification is associated with known prognostic parameters. By resolving the patterns of driver event ordering, co-occurrence, and mutual exclusivity at clone level, we show the deterministic nature of clonal evolution. ccRCC can be grouped into seven evolutionary subtypes, ranging from tumors characterized by early fixation of multiple mutational and copy number drivers and rapid metastases to highly branched tumors with >10 subclonal drivers and extensive parallel evolution associated with attenuated progression. We identify genetic diversity and chromosomal complexity as determinants of patient outcome. Our insights reconcile the variable clinical behavior of ccRCC and suggest evolutionary potential as a biomarker for both intervention and surveillance

Induction of APOBEC3 exacerbates DNA replication stress and chromosomal instability in early breast and lung cancer evolution

APOBEC3 enzymes are cytosine deaminases implicated in cancer. Precisely when APOBEC3 expression is induced during cancer development remains to be defined. Here we show that specific APOBEC3 genes are upregulated in breast DCIS, and in pre-invasive lung cancer lesions coincident with cellular proliferation. We observe evidence of APOBEC3-mediated subclonal mutagenesis propagated from TRACERx pre-invasive to invasive NSCLC lesions. We find that APOBEC3B exacerbates DNA replication stress and chromosomal instability through incomplete replication of genomic DNA, manifested by accumulation of mitotic ultrafine bridges and 53BP1 nuclear bodies in the G1 phase of the cell cycle. Analysis of TRACERx NSCLC clinical samples and mouse lung cancer models, revealed APOBEC3B expression driving replication stress and chromosome missegregation. We propose that APOBEC3 is functionally implicated in the onset of chromosomal instability and somatic mutational heterogeneity in pre-invasive disease, providing fuel for selection early in cancer evolution

Kapa kazeinski gen (CSN3) pri konju

Kappa casein (K-CN) is milk protein that determines the size and specific function of the casein micelles, and its clevage by chymosine is responsible for milk coagulation. Any variation in gene promoter or coding sequence may change the expression of the gene or amino acid sequence, effecting functional properties of the protein. The mature k-cn is encoded by part of the exon 3 and the entire exon 4. Since exon 3 has 33 bp and exon 4 is 497 bp long, the major part of the protein is encoded by exon 4. In this study we identified two SNPs in exon 1 and two in exon 4 of the horse kappa casein gene(CSN3) and genotyped them in three horse breeds. The nucleotide sequence of the first exon was included in this study due to its possible role in the regulation of the CSN3 expression. Because these polymorphisms were analysed for the first time, we used a reference method (RFLP) or at least two other complementig methods (Bi-PASA/PIRA and ASA-PCR/PIRA), for molecular genetic analysis of above mentioned SNPs. The highest variation in genotype frequencies was present in Slovenian cold blood breed. SNPs in exon 4 cause amino acid (AA) change in the mature product, and may very well render chemical/functional properties of the protein. Analysis of the consequences caused bz changes in AA sequence, bz online avaible program tools, comfirmed our hypothesis.Kapa kazein (K-CN) je mlečni protein, ki določa velikost in specifično funkcijo kazeinskih micel, njegova razgradnja s kimozinom pa je odgovorna za koagulacijo mleka. Sprememba v promotorju ali kodirajoèem področju gena lahko vpliva na njegovo izražanje, oziroma spremeni aminokislinsko zaporedje, s tem pa vpliva na funkcionalnost proteina. Zrel K-CN protein je deloma kodiran z eksonom 3 in s celotnim eksonom 4. Zaporedje eksona 1 smo vključili v raziskavo, ker je moyno, da ima regulatorno vlogo. Ker je ekson 3 dolg 33 baznih parov, ekson 4 pa ima 497 baznih parov, je pretežni del proteina kodiran z eksonom 4. V tej študiji smo izvedli genetsko analizo dveh nukleotidnih zamenjav v eksonu 1 in dveh v eksonu 4 v genu za kapa kazein (CSN3) pri konju in jih genotipizirali pri treh pasmah. Ker ti polimorfizmi se nikoli niso bili analizirani, smo za genetsko molekularno analizo omenjenih polimorfizmov, uporabili referenčno metodo (RFLP) ali vsaj dve drugi dopolnjujoči metodi (Bi-PASA/PIRA in ASA-PCR/PIRA). Največja raznolikost genotipov je bila prisotna pri Slovenski hladnokrvni pasmi. Nukleotidni zamenjavi v eksonu 4 povzročita zamenjavo aminokislin v končnem produktu, kar pa lahko spremeni kemične/fukcionalne lastnosti proteina. Analiza posledic sprememb aminokislinske sekvence, s programi na internetu, je potrdila naso hipotezo

Cancer-specific loss of p53 leads to a modulation of myeloid and T cell responses

Loss of p53 function contributes to the development of many cancers. While cell-autonomous consequences of p53 mutation have been studied extensively, the role of p53 in regulating the anti-tumor immune response is still poorly understood. Here, we show that loss of p53 in cancer cells modulates the tumor-immune landscape to circumvent immune destruction. Deletion of p53 promotes the recruitment and instruction of suppressive myeloid CD11b cells, in part through increased expression of CXCR3/CCR2-associated chemokines and macrophage colony-stimulating factor (M-CSF), and attenuates the CD4 T helper 1 (Th1) and CD8 T cell responses in vivo. p53-null tumors also show an accumulation of suppressive regulatory T (Treg) cells. Finally, we show that two key drivers of tumorigenesis, activation of KRAS and deletion of p53, cooperate to promote immune tolerance. [Abstract copyright: Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.

Induction of APOBEC3 Exacerbates DNA Replication Stress and Chromosomal Instability in Early Breast and Lung Cancer Evolution

APOBEC3 enzymes are cytosine deaminases implicated in cancer. Precisely when APOBEC3 expression is induced during cancer development remains to be defined. Here we show that specific APOBEC3 genes are upregulated in breast ductal carcinoma in situ, and in preinvasive lung cancer lesions coincident with cellular proliferation. We observe evidence of APOBEC3-mediated subclonal mutagenesis propagated from TRACERx preinvasive to invasive non-small cell lung cancer (NSCLC) lesions. We find that APOBEC3B exacerbates DNA replication stress and chromosomal instability through incomplete replication of genomic DNA, manifested by accumulation of mitotic ultrafine bridges and 53BP1 nuclear bodies in the G(1) phase of the cell cycle. Analysis of TRACERx NSCLC clinical samples and mouse lung cancer models revealed APOBEC3B expression driving replication stress and chromosome missegregation. We propose that APOBEC3 is functionally implicated in the onset of chromosomal instability and somatic mutational heterogeneity in preinvasive disease, providing fuel for selection early in cancer evolution. SIGNIFICANCE : This study reveals the dynamics and drivers of APOBEC3 gene expression in preinvasive disease and the exacerbation of cellular diversity by APOBEC3B through DNA replication stress to promote chromosomal instability early in cancer evolution