Colorectal cancer can be categorized into two major molecular subtypes according to the status of their DNA proofreading and repair machinery. The DNA repair status of tumor cells plays a major role ...in shaping the immune landscape of tumors and in determining the clinical response of colorectal cancer patients to immune checkpoint blockade therapies. Colorectal cancers that develop in a context of DNA mismatch repair or polymerase proofreading deficiency are generally conspicuously infiltrated by effector memory T cells and are associated with an improved clinical prognosis relative to their replication repair-proficient counterpart. While mismatch repair-deficient colorectal cancers, and most likely POLE and POLD1-mutated cancers, are amenable to immune checkpoint blockade therapies, the promise of immunotherapy still remains unfulfilled for for the majority of colorectal cancer patients. This review focusses on the role of the immune system in the tumorigenesis and clinical behavior of colorectal cancer. Furthermore, we discuss how latest advances in the fields of genomics and oncoimmunology may pave the way to broaden the scope of immunotherapy for this disease.
Colorectal cancer has high incidence and associated mortality worldwide. Screening programs are recommended for men and women over 50. Intermediate screens such as fecal immunochemical testing (FIT) ...select patients for colonoscopy with suboptimal sensitivity. Additional biomarkers could improve the current scenario.
We included 2,893 individuals with a positive FIT test. They were classified as cases when a high-risk lesion for colorectal cancer was detected after colonoscopy, whereas the control group comprised individuals with low-risk or no lesions. 65 colorectal cancer risk genetic variants were genotyped. Polygenic risk score (PRS) and additive models for risk prediction incorporating sex, age, FIT value, and PRS were generated.
Risk score was higher in cases compared with controls per allele OR = 1.04; 95% confidence interval (CI), 1.02-1.06; P < 0.0001. A 2-fold increase in colorectal cancer risk was observed for subjects in the highest decile of risk alleles (≥65), compared with those in the first decile (≤54; OR = 2.22; 95% CI, 1.59-3.12; P < 0.0001). The model combining sex, age, FIT value, and PRS reached the highest accuracy for identifying patients with a high-risk lesion cross-validated area under the ROC curve (AUROC): 0.64; 95% CI, 0.62-0.66.
This is the first investigation analyzing PRS in a two-step colorectal cancer screening program. PRS could improve current colorectal cancer screening, most likely for higher at-risk subgroups. However, its capacity is limited to predict colorectal cancer risk status and should be complemented by additional biomarkers.
PRS has capacity for risk stratification of colorectal cancer suggesting its potential for optimizing screening strategies alongside with other biomarkers.
Abstract
Background
GRP94 is a glucose-regulated protein critical for survival in endoplasmic reticulum stress. Expression of GRP94 is associated with cellular transformation and increased ...tumorigenicity in breast cancer. Specifically, overexpression of GRP94 predicts brain metastasis (BM) in breast carcinoma patients with either triple negative or ErbB2 positive tumors. The aim of this study was to understand if microenvironmental regulation of GRP94 expression might be a hinge orchestrating BM progression.
Methods
GRP94 ablation was performed in a BM model BR-eGFP-CMV/Luc-V5CA1 (BRV5CA1) of breast cancer. In vitro results were validated in a dataset of 29 metastases in diverse organs from human breast carcinomas and in BM tissue from tumors of different primary origin. BM patient-derived xenografts (PDXs) were used to test sensitivity to the therapeutic approach.
Results
BMs that overexpress GRP94 as well as tumor necrosis factor receptor-associated factor 2 are more resistant to glucose deprivation by induction of anti-apoptotic proteins (B-cell lymphoma 2 and inhibitors of apoptosis proteins) and engagement of pro-survival autophagy. GRP94 ablation downregulated autophagy in tumor cells, resulting in increased BM survival in vivo. These results were validated in a metastasis dataset from human patients, suggesting that targeting autophagy might be strategic for BM prevention. Indeed, hydroxychloroquine treatment of preclinical models of BM from PDX exerts preventive inhibition of tumor growth (P < 0.001).
Conclusions
We show that GRP94 is directly implicated in BM establishment by activating pro-survival autophagy. Disruption of this compensatory fueling route might prevent metastatic growth.
In colorectal carcinogenesis, genetic alterations in RAS and BRAF oncogenes play an important role for cancer initiation and/or progression and represent a key focus in the search for targeted ...therapies. Despite many years of research and a great amount of studies, until very recently this pathway was considered extremely hard to downregulate to obtain a significant clinical impact in colorectal cancer patients. But better times are coming with the advent of new promising drugs and combinations strategies.
In this review, we go over the biological characteristics of the MAPK pathway in colorectal tumors, while illustrating the clinical correlation of RAS and BRAF mutations, particularly its prognostic and predictive value. We also present newly data about recent improvements in the treatment strategy for patients harboring these types of tumors.
With great advances in the knowledge of molecular basis of RAS and BRAF mutant colorectal cancer in conjunction with biotechnology development and the constant effort for improvement, in the near future many new therapeutic options would be available for the management of this group of patient with dismal prognosis.
Abstract The incidence of colorectal cancer (CRC) among individuals younger than age 50 (early-onset CRC EOCRC) has substantially increased, and yet the etiology and molecular mechanisms underlying ...this alarming rise remain unclear. We compared tumor-associated T-cell repertoires between EOCRC and average-onset CRC (AOCRC) to uncover potentially unique immune microenvironment-related features by age of onset. Our discovery cohort included 242 patients who underwent surgical resection at Cleveland Clinic from 2000 to 2020. EOCRC was defined as younger than age 50 years at diagnosis (N = 126) and AOCRC as 60 years of age or older (N = 116). T-cell receptor (TCR) abundance and clonality were measured by immunosequencing of tumors. Logistic regression models were used to evaluate the associations between TCR repertoire features and age of onset, adjusting for sex, race, tumor location, and stage. Findings were replicated in 152 EOCRC and 1984 AOCRC cases from the Molecular Epidemiology of Colorectal Cancer Study. EOCRC tumors had significantly higher TCR diversity compared with AOCRC tumors in the discovery cohort (odds ratio OR = 0.44, 95% confidence interval CI = 0.32 to 0.61, P < .0001). This association was also observed in the replication cohort (OR = 0.74, 95% CI = 0.62 to 0.89, P = .0013). No significant differences in TCR abundance were observed between EOCRC and AOCRC in either cohort. Higher TCR diversity, suggesting a more diverse intratumoral T-cell response, is more frequently observed in EOCRC than AOCRC. Further studies are warranted to investigate the role of T-cell diversity and the adaptive immune response more broadly in the etiology and outcomes of EOCRC.
If not properly regulated, the inflammatory immune response can promote carcinogenesis, as evident in colorectal cancer (CRC). Aiming to gain mechanistic insight into the link between inflammation ...and CRC, we perform transcriptomics analysis of human CRC, identifying a strong correlation between expression of the serine protease granzyme A (GzmA) and inflammation. In a dextran sodium sulfate and azoxymethane (DSS/AOM) mouse model, deficiency and pharmacological inhibition of extracellular GzmA both attenuate gut inflammation and prevent CRC development, including the initial steps of cell transformation and epithelial-to-mesenchymal transition. Mechanistically, extracellular GzmA induces NF-κB-dependent IL-6 production in macrophages, which in turn promotes STAT3 activation in cultured CRC cells. Accordingly, colon tissues from DSS/AOM-treated, GzmA-deficient animals present reduced levels of pSTAT3. By identifying GzmA as a proinflammatory protease that promotes CRC development, these findings provide information on mechanisms that link immune cell infiltration to cancer progression and present GzmA as a therapeutic target for CRC.
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•GZMA mRNA expression correlates with inflammation in human CRC patients•GzmA deficiency reduces gut inflammation and colorectal cancer development•Therapeutic GzmA inhibition in WT mice reduces colorectal cancer development•GzmA induces IL-6 production in macrophages activating pSTAT3 in colon cancer cells
Santiago et al. show that extracellular granzyme A (GzmA) contributes to gut inflammation and colorectal cancer (CRC) development by promoting IL-6 production in macrophages. Therapeutic inhibition of GzmA attenuates inflammation and CRC development, suggesting that GzmA could be useful to treat gut inflammation and prevent CRC.
The dysregulated immune response and inflammation resulting in severe COVID-19 are still incompletely understood. Having recently determined that aberrant death-ligand-induced cell death can cause ...lethal inflammation, we hypothesized that this process might also cause or contribute to inflammatory disease and lung failure following SARS-CoV-2 infection. To test this hypothesis, we developed a novel mouse-adapted SARS-CoV-2 model (MA20) that recapitulates key pathological features of COVID-19. Concomitantly with occurrence of cell death and inflammation, FasL expression was significantly increased on inflammatory monocytic macrophages and NK cells in the lungs of MA20-infected mice. Importantly, therapeutic FasL inhibition markedly increased survival of both, young and old MA20-infected mice coincident with substantially reduced cell death and inflammation in their lungs. Intriguingly, FasL was also increased in the bronchoalveolar lavage fluid of critically-ill COVID-19 patients. Together, these results identify FasL as a crucial host factor driving the immuno-pathology that underlies COVID-19 severity and lethality, and imply that patients with severe COVID-19 may significantly benefit from therapeutic inhibition of FasL.
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