Keratin 7 expression in colorectal cancer--freak of nature or significant finding?

Fusobacterium nucleatum and its metabolite hydrogen sulfide alter gut microbiota composition and autophagy process and promote colorectal cancer progression

IMPORTANCE

Colorectal cancer (CRC) is the second most common cancer in the world; the main treatment for CRC is immunosuppressive therapy, but this therapy is only effective for a small percentage of CRC patients, so there is an urgent need for a treatment with fewer side effects and higher efficacy. This study demonstrated that Fusobacterium nucleatum with increased abundance in CRC can regulate the autophagy process and disrupt normal intestinal microbiota by producing hydrogen sulfide, factors that may be involved in the development and progression of CRC. This study may provide a reference for future CRC treatment options that are efficient and have fewer side effects.

Identifying endoplasmic reticulum stress-related molecular subtypes and prognostic model for predicting the immune landscape and therapy response in pancreatic cancer

Endoplasmic reticulum stress (ERS) is caused by the accumulation of intracellular misfolded or unfolded proteins and is associated with cancer development. In this study, pan-cancer analysis revealed complex genetic variations, including copy number variation, methylation, and somatic mutations for ERS-related genes (ERGs) in 33 kinds of cancer. Consensus clustering divided pancreatic cancer (PC) patients from TCGA and GEO databases into two ERS-related subtypes: ERGcluster A and B. Compared with ERGcluster A, ERGcluster B had a more active ERS state and worse prognosis. Subsequently, the ERS-related prognostic model was established to quantify the ERS score for a single sample. The patient with a low ERS score had remarkably longer survival times. ssGSEA and CIBERSORT algorithms revealed that activated B cells and CD8+ T cells had higher infiltration in the low ERS score group, but higher infiltration of activated CD4+ T cells, activated dendritic cells, macrophages, and neutrophils in the high ERS score group. Drug sensitivity analysis indicated the low ERS score group had a better response to gemcitabine, paclitaxel, 5-fluorouracil, oxaliplatin, and irinotecan. RT-qPCR validated that MET, MUC16, and KRT7 in the model had higher expression levels in pancreatic tumour tissues. Single-cell analysis further revealed that MET, MUC16, and KRT7 were mainly expressed in cancer cells in PC tumour microenvironment. In all, we first constructed the ERS-related molecular subtypes and prognostic model in PC. Our research highlighted the vital role of ERS in PC and contributed to further research on molecular mechanisms and novel therapeutic strategies for PC in the future.

Colonocyte keratin 7 is expressed de novo in inflammatory bowel diseases and associated with pathological changes and drug-resistance

The clinical course of IBD, characterized by relapses and remissions, is difficult to predict. Initial diagnosis can be challenging, and novel disease markers are needed. Keratin 7 (K7) is a cytoskeletal intermediate filament protein not expressed in the colonic epithelium but has been reported in IBD-associated colorectal tumors. Our aim was to analyze whether K7 is expressed in chronic colonic inflammatory diseases and evaluate its potential as a novel biomarker. K7 was analyzed in two patient cohorts using immunohistochemistry-stained colon samples and single-cell quantitative digital pathology methods. K7 was correlated to pathological changes and clinical patient characteristics. Our data shows that K7 is expressed de novo in the colonic epithelium of ulcerative colitis and Crohn's disease IBD patients, but not in collagenous or lymphocytic colitis. K7 mRNA expression was significantly increased in colons of IBD patients compared to controls when assessed in publicly available datasets. While K7 increased in areas with inflammatory activity, it was not expressed in specific crypt compartments and did not correlate with neutrophils or stool calprotectin. K7 was increased in areas proximal to pathological alterations and was most pronounced in drug-resistant ulcerative colitis. In conclusion, colonic epithelial K7 is neo-expressed selectively in IBD patients and could be investigated for its potential as a disease biomarker.

Loss of SATB2 expression correlates with cytokeratin 7 and PD-L1 tumor cell positivity and aggressiveness in colorectal cancer

Colorectal carcinoma (CRC) is a disease that causes significant morbidity and mortality worldwide. To improve treatment, new biomarkers are needed to allow better patient risk stratification in terms of prognosis. This study aimed to clarify the prognostic significance of colonic-specific transcription factor special AT-rich sequence-binding protein 2 (SATB2), cytoskeletal protein cytokeratin 7 (CK7), and immune checkpoint molecule programmed death-ligand 1 (PD-L1). We analyzed a cohort of 285 patients with surgically treated CRC for quantitative associations among the three markers and five traditional prognostic indicators (i.e., tumor stage, histological grade, variant morphology, laterality, and mismatch-repair/MMR status). The results showed that loss of SATB2 expression had significant negative prognostic implications relative to overall survival (OS) and cancer-specific survival (CSS), significantly shortened 5 years OS and CSS and 10 years CSS in patients with CRC expressing CK7, and borderline insignificantly shortened OS in patients with PD-L1 + CRC. PD-L1 showed a significant negative impact in cases with strong expression (membranous staining in 50-100% of tumor cells). Loss of SATB2 was associated with CK7 expression, advanced tumor stage, mucinous or signet ring cell morphology, high grade, right-sided localization but was borderline insignificant relative to PD-L1 expression. CK7 expression was associated with high grade and SATB2 loss. Additionally, a separate analysis of 248 neoadjuvant therapy-naïve cases was performed with mostly similar results. The loss of SATB2 and CK7 expression were significant negative predictors in the multivariate analysis adjusted for associated parameters and patient age. In summary, loss of SATB2 expression and gain of CK7 and strong PD-L1 expression characterize an aggressive phenotype of CRC.

Roles of Keratins in Intestine

Keratins make up a major portion of epithelial intermediate filament proteins. The widely diverse keratins are found in both the small and large intestines. The human intestine mainly expresses keratins 8, 18, 19, and 20. Many of the common roles of keratins are for the integrity and stability of the epithelial cells. The keratins also protect the cells and tissue from stress and are biomarkers for some diseases in the organs. Although an increasing number of studies have been performed regarding keratins, the roles of keratin in the intestine have not yet been fully understood. This review focuses on discussing the roles of keratins in the intestine. Diverse studies utilizing mouse models and samples from patients with intestinal diseases in the search for the association of keratin in intestinal diseases have been summarized.

Cytokeratin 7 and cytokeratin 20 expression in cancer: A tissue microarray study on 15,424 cancers

Combined analysis of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) is often used for assessing the origin of metastatic cancer. To evaluate the diagnostic utility of CK7 and CK20, tissue microarrays containing 15,424 samples from 120 different tumor types and subtypes and 608 samples of 76 different normal tissue types were analyzed by immunohistochemistry. CK7 positivity was seen in 52% (8.7% weak, 5.9% moderate, 37% strong) and CK20 positivity in 23% (5.1% weak, 3.4% moderate, 15% strong) of interpretable tumors. Of 8390 positive tumors, 1181 (14%) showed positivity for CK7 and CK20, 5380 (64%) showed positivity for CK7 alone, and 1829 (22%) showed positivity for CK20 alone. CK20 predominated in gastrointestinal tract, urothelial and Merkel cell carcinomas. CK7 was usually negative in prostate cancer and colorectal cancer. Combined evaluation of CK7/CK20 revealed the best diagnostic utility in CK20 positive tumors, where CK7 negativity is often linked to colorectal origin while CK7 positivity argues for urothelial origin or mucinous ovarian cancer. Associations with unfavorable tumor features were found for cytokeratin 7 loss in breast cancer of no special type, urothelial and renal cell carcinomas, for CK7 overexpression in high-grade serous ovarian and gastric cancer, and for CK20 overexpression in urothelial carcinoma. CK20 loss was linked to MSI in gastric (p = 0.0291) and colorectal adenocarcinoma (p < 0.0001). These analyses provide comprehensive data on the frequency of CK7 and CK20 immunostaining - alone or in combination - in human cancers. These data facilitate interpretation of CK7/CK20 immunostaining in cancers.

BRAF-mutated colorectal adenocarcinomas: pathological heterogeneity and clinical implications

Advances in molecular biology have markedly increased our understanding of the heterogeneous molecular landscape of colorectal cancer (CRC). Up to 15% of CRCs harbor the BRAF p.V600E somatic mutation (BRAFmt), a well-established negative prognostic marker in patients with metastatic CRC (mCRC). The BEACON CRC trial set a new standard of care in patients with progressive BRAFmt cancers, consisting of the combination of encorafenib and cetuximab. On these bases, BRAF mutational testing is now recommended in patients with mCRC. However, efforts are needed to further stratify patients carrying this mutation. Here, we discuss the heterogeneous pathologic and molecular landscape of BRAFmt CRCs, focusing on the promises and pitfalls of molecular diagnostics, on novel biomarkers to improve patients' stratification and on the current diagnostic scenario for CRC. We believe that a better stratification based on histopathological features and novel molecular biomarkers should be performed to optimize patient management and therapeutic decision-making.

Novel Diagnostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is still a leading cause of cancer death worldwide. Less than half of cases are diagnosed when the cancer is locally advanced. CRC is a heterogenous disease associated with a number of genetic or somatic mutations. Diagnostic markers are used for risk stratification and early detection, which might prolong overall survival. Nowadays, the widespread use of semi-invasive endoscopic methods and feacal blood tests characterised by suboptimal accuracy of diagnostic results has led to the detection of cases at later stages. New molecular noninvasive tests based on the detection of CRC alterations seem to be more sensitive and specific then the current methods. Therefore, research aiming at identifying molecular markers, such as DNA, RNA and proteins, would improve survival rates and contribute to the development of personalized medicine. The identification of “ideal” diagnostic biomarkers, having high sensitivity and specificity, being safe, cheap and easy to measure, remains a challenge. The purpose of this review is to discuss recent advances in novel diagnostic biomarkers for tumor tissue, blood and stool samples in CRC patients.

Cytokeratin 7 expression as a predictor of an unfavorable prognosis in colorectal carcinoma

Colorectal carcinoma (CRC) is associated with significant morbidity and mortality worldwide. Cytokeratins (CKs) are widely expressed in various types of carcinomas, whereas in CRC it is usually CK7 − and CK20 + . A subset of CRCs is CK7 + . This study aims to determine the prevalence of CK7 expression in CRC and its impact on overall survival. We analyzed 300 randomly selected surgically treated CRC cases using paraffin embedded tumor tissue samples and evaluated CK7 and CK20 expression using the tissue microarray method. Tumors with positivity > 10% and > 25% of tumor cells were considered CK7 and CK20 positive, respectively. Expression of both CKs and several clinical-pathological variables (stage, grade, laterality, mismatch-repair/MMR status) were evaluated using patient follow up data (Kaplan–Meier analysis of cancer-specific survival (CSS)). Significant results include shorter CSS (restricted mean 4.98 vs. 7.74 years, P = 0.007) and 5-year survival (29.4% vs. 64.6%, P = 0.0221) in CK7 + tumors compared to CK7 − tumors, respectively; without significant association with grade, stage or right-sided location. These results were significant in a multivariate analysis. CK20 + tumors are more frequently MMR-proficient and left-sided. MMR-deficient tumors are more frequently right-sided and had longer survival. CK7 expression, right-sided location (rmean CSS 6.83 vs. 8.0 years, P = 0.043), MMR-proficiency (rmean CSS 7.41 vs. 9.32 years, P = 0.012), and UICC stages III + IV (rmean CSS 6.03 vs. 8.92 years, P < 0.001) of the tumor correlated with negative prognostic outcomes, whereas the most significant results concern stage and CK7 positivity. The result concerning negative prognostic role of CK7 differs from those obtained by several previous studies focused on this topic.

Robust Prognostic Subtyping of Muscle-Invasive Bladder Cancer Revealed by Deep Learning-Based Multi-Omics Data Integration

Muscle-invasive bladder cancer (MIBC) is the most common urinary system carcinoma associated with poor outcomes. It is necessary to develop a robust classification system for prognostic prediction of MIBC. Recently, increasing omics data at different levels of MIBC were produced, but few integration methods were used to classify MIBC that reflects the patient’s prognosis. In this study, we constructed an autoencoder based deep learning framework to integrate multi-omics data of MIBC and clustered samples into two different subgroups with significant overall survival difference (P = 8.11 × 10^-5). As an independent prognostic factor relative to clinical information, these two subtypes have some significant genomic differences. Remarkably, the subtype of poor prognosis had significant higher frequency of chromosome 3p deletion. Immune decomposition analysis results showed that these two MIBC subtypes had different immune components including macrophages M1, resting NK cells, regulatory T cells, plasma cells, and naïve B cells. Hallmark gene set enrichment analysis was performed to investigate the functional character difference between these two MIBC subtypes, which revealed that activated IL-6/JAK/STAT3 signaling, interferon-alpha response, reactive oxygen species pathway, and unfolded protein response were significantly enriched in upregulated genes of high-risk subtype. We constructed MIBC subtyping models based on multi-omics data and single omics data, respectively, and internal and external validation datasets showed the robustness of the prediction model as well as its ability of prognosis (P < 0.05 in all datasets). Finally, through bioinformatics analysis and immunohistochemistry experiments, we found that KRT7 can be used as a biomarker reflecting MIBC risk.

RNA sequencing of long-term label-retaining colon cancer stem cells identifies novel regulators of quiescence

Recent data suggest that therapy-resistant quiescent cancer stem cells (qCSCs) are the source of relapse in colon cancer. Here, using colon cancer patient-derived organoids and xenografts, we identify rare long-term label-retaining qCSCs that can re-enter the cell cycle to generate new tumors. RNA sequencing analyses demonstrated that these cells display the molecular hallmarks of quiescent tissue stem cells, including expression of p53 signaling genes, and are enriched for transcripts common to damage-induced quiescent revival stem cells of the regenerating intestine. In addition, we identify negative regulators of cell cycle, downstream of p53, that we show are indicators of poor prognosis and may be targeted for qCSC abolition in both p53 wild-type and mutant tumors. These data support the temporal inhibition of downstream targets of p53 signaling, in combination with standard-of-care treatments, for the elimination of qCSCs and prevention of relapse in colon cancer.

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Colon tumors contain therapy-resistant quiescent cancer stem cells (qCSCs)

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qCSC gene expression mirrors that of quiescent stem cells of the regenerating gut

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qCSCs are enriched for p53 signaling genes

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qCSC elimination may be achieved by inhibiting downstream targets of p53 signaling

Prognostic relevance and putative histogenetic role of cytokeratin 7 and MUC5AC expression in Crohn's disease-associated small bowel carcinoma

Most Crohn’s disease-associated small bowel carcinomas (CrD-SBCs) are diagnosed in advanced stage and have poor prognosis. To improve diagnosis and therapy, a better knowledge of tumour precancerous lesions, histotypes and prognostic factors is needed. We investigated histologically and immunohistochemically 52 CrD-SBCs and 51 small bowel carcinomas unrelated to inflammatory disease, together with their tumour-associated mucosa, looking for Crohn-selective changes. Histologic patterns and phenotypic markers potentially predictive of CrD-SBC histogenesis and prognosis were analysed. Cytokeratin 7 or MUC5AC-positive metaplastic changes were found in about half of investigated CrD-SBCs, significantly more frequently than in CrD-unrelated SBCs. They correlated with metaplastic changes of their associated mucosa, while being absent in normal ileal mucosa. Histologic patterns suggestive for progression of some cytokeratin 7 and/or MUC5AC-positive metaplastic lesions into cancer of the same phenotype were also observed. Patient survival analyses showed that tumour cytokeratin 7 or MUC5AC expression and non-cohesive histotype were adverse prognostic factors at univariable analysis, while cytokeratin 7 and non-cohesive histotype were also found to predict worse survival in stage- and age-inclusive multivariable analyses. Besides conventional dysplasia, hyperplasia-like non-conventional lesions were observed in CrD-SBC-associated mucosa, with patterns suggestive for a histogenetic link with adjacent cancer. In conclusion the cytokeratin 7 and/or MUC5AC-positive metaplastic foci and the non-conventional growths may have a role in cancer histogenesis, while tumour cytokeratin 7 and non-cohesive histotype may also predict poor patient survival. Present findings are worth being considered in future prospective histogenetic and clinical studies.

Role of Epithelial-Mesenchymal Plasticity in Pseudomyxoma Peritonei: Implications for Locoregional Treatments

The mechanisms by which neoplastic cells disseminate from the primary tumor to metastatic sites, so-called metastatic organotropism, remain poorly understood. Epithelial-mesenchymal transition (EMT) plays a role in cancer development and progression by converting static epithelial cells into the migratory and microenvironment-interacting mesenchymal cells, and by the modulation of chemoresistance and stemness of tumor cells. Several findings highlight that pathways involved in EMT and its reverse process (mesenchymal-epithelial transition, MET), now collectively called epithelial-mesenchymal plasticity (EMP), play a role in peritoneal metastases. So far, the relevance of factors linked to EMP in a unique peritoneal malignancy such as pseudomyxoma peritonei (PMP) has not been fully elucidated. In this review, we focus on the role of epithelial-mesenchymal dynamics in the metastatic process involving mucinous neoplastic dissemination in the peritoneum. In particular, we discuss the role of expression profiles and phenotypic transitions found in PMP in light of the recent concept of EMP. A better understanding of EMP-associated mechanisms driving peritoneal metastasis will help to provide a more targeted approach for PMP patients selected for locoregional interventions involving cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

Keratin intermediate filaments in the colon: guardians of epithelial homeostasis

Keratin intermediate filament proteins are major cytoskeletal components of the mammalian simple layered columnar epithelium in the gastrointestinal tract. Human colon crypt epithelial cells express keratins 18, 19 and 20 as the major type I keratins, and keratin 8 as the type II keratin. Keratin expression patterns vary between species, and mouse colonocytes express keratin 7 as a second type II keratin. Colonic keratin patterns change during cell differentiation, such that K20 increases in the more differentiated crypt cells closer to the central lumen. Keratins provide a structural and mechanical scaffold to support cellular stability, integrity and stress protection in this rapidly regenerating tissue. They participate in central colonocyte processes including barrier function, ion transport, differentiation, proliferation and inflammatory signaling. The cell-specific keratin compositions in different epithelial tissues has allowed for the utilization of keratin-based diagnostic methods. Since the keratin expression pattern in tumors often resembles that in the primary tissue, it can be used to recognize metastases of colonic origin. This review focuses on recent findings on the biological functions of mammalian colon epithelial keratins obtained from pivotal in vivo models. We also discuss the diagnostic value of keratins in chronic colonic disease and known keratin alterations in colon pathologies. This review describes the biochemical properties of keratins and their molecular actions in colonic epithelial cells and highlights diagnostic data in colorectal cancer and inflammatory bowel disease patients, which may facilitate the recognition of disease subtypes and the establishment of personal therapies in the future.

Fusobacterium nucleatum host-cell binding and invasion induces IL-8 and CXCL1 secretion that drives colorectal cancer cell migration

Fusobacterium nucleatum is implicated in accelerating colorectal cancer (CRC) and is found within metastatic CRC cells in patient biopsies. Here, we found that bacterial invasion of CRC cells and cocultured immune cells induced a differential cytokine secretion that may contribute to CRC metastasis. We used a modified galactose kinase markerless gene deletion approach and found that F. nucleatum invaded cultured HCT116 CRC cells through the bacterial surface adhesin Fap2. In turn, Fap2-dependent invasion induced the secretion of the proinflammatory cytokines IL-8 and CXCL1, which are associated with CRC progression and promoted HCT116 cell migration. Conditioned medium from F. nucleatum-infected HCT116 cells caused naïve cells to migrate, which was blocked by depleting CXCL1 and IL-8 from the conditioned medium. Cytokine secretion from HCT116 cells and cellular migration were attenuated by inhibiting F. nucleatum host-cell binding and entry using galactose sugars, l-arginine, neutralizing membrane protein antibodies, or fap2 deletion. F. nucleatum also induces the mobilization of immune cells in the tumor microenvironment. However, in neutrophils and macrophages, the bacterial-induced secretion of cytokines was Fap2 independent. Thus, our findings show that F. nucleatum both directly and indirectly modulates immune and cancer cell signaling and migration. Because increased IL-8 and CXCL1 production in tumors is associated with increased metastatic potential and cell seeding, poor prognosis, and enhanced recruitment of tumor-associated macrophages and fibroblasts, we propose that inhibition of host-cell binding and invasion, potentially through vaccination or novel galactoside compounds, could be an effective strategy for reducing F. nucleatum-associated CRC metastasis.

Fusobacterium nucleatum promotes colorectal cancer metastasis by modulating KRT7-AS/KRT7

The enrichment of Fusobacterium nucleatum (Fn) has been identified in CRC patients and associated with worse outcomes. However, whether Fn was involved in the metastasis of CRC was not well determined. Here, we found that the abundance of Fn was significantly increased in CRC patients with lymph nodes metastasis. To further clarify the role of Fn in CRC metastasis, we performed transwell and wound healing assays after incubating CRC cell lines with or without Fn and injected Fn-treated or untreated CRC cells into nude mice via tail vein. The results indicated that Fn infection promoted CRC cells migration in vitro, as well as lung metastasis in vivo. Interestingly, colonization of Fn was detected in metastatic lung lesions of nude mice by fluorescence in situ hybridization. Mechanistically, RNA sequencing and validation study revealed that Fn significantly upregulated the expression of long non-coding RNA Keratin7-antisense (KRT7-AS) and Keratin7 (KRT7) in CRC cells. Importantly, Fn-induced CRC lung metastasis was attenuated by the depletion of KRT7-AS. In addition, KRT7-AS facilitated CRC cells migration by upregulating KRT7. Subsequently, we found that NF-κB signaling pathway was involved in the upregulation of KRT7-AS upon Fn infection. In conclusion, Fn infection upregulated KRT7-AS/KRT7 by activating NF-κB pathway, which promoted CRC cell migration in vitro and metastasis in vivo.

The heterogeneous clinical and pathological landscapes of metastatic Braf-mutated colorectal cancer

Colorectal cancer (CRC) is a complex and molecularly heterogeneous disease representing one of the most frequent causes of cancer-related death worldwide. About 8–15% of CRCs harbor a mutation in BRAF gene, a proto-oncogene involved in cell proliferation, differentiation and survival through the MAPK signaling cascade. The acquisition of BRAF mutation is an early event in the “serrated” CRC carcinogenetic pathway and is associated with specific and aggressive clinico-pathological and molecular features. Despite that the presence of BRAF mutation is a well-recognized negative prognostic biomarker in metastatic CRC (mCRC), a great heterogeneity in survival outcome characterizes these patients, due to the complex, and still not completely fully elucidated, interactions between the clinical, genetic and epigenetic landscape of BRAF mutations. Because of the great aggressiveness of BRAF-mutated mCRCs, only 60% of patients can receive a second-line chemotherapy; so intensive combined and tailored first-line approach could be a potentially effective strategy, but to minimize the selective pressure of resistant clones and to reduce side effects, a better stratification of patients bearing BRAF mutations is needed.

Targeted multiplex proteomics for molecular prescreening and biomarker discovery in metastatic colorectal cancer

Protein biomarkers are widely used in cancer diagnosis, prognosis, and prediction of treatment response. Here we introduce the use of targeted multiplex proteomics (TMP) as a tool to simultaneously measure a panel of 54 proteins involved in oncogenic, tumour suppression, drug metabolism and resistance, in patients with metastatic colorectal cancer (mCRC). TMP provided valuable diagnostic information by unmasking an occult neuroendocrine differentiation and identifying a misclassified case based on abnormal proteins phenotype. No significant differences in protein levels between unpaired primary and metastatic samples were observed. Four proteins were found differentially expressed in KRAS-mutant as compared to wild-type tumours (overexpressed in mutant: KRAS, EGFR; overexpressed in wild-type: TOPO1, TOP2A). Survival analyses revealed the association between mesothelin expression and poor overall survival, whereas lack of PTEN protein expression associated with lower progression-free survival with anti-EGFR-based therapy in the first-line setting for patients with RAS wild-type tumour. Finally, outlier analysis identified putative targetable proteins in 65% of patients lacking a targetable genomic alteration. Our data show that TMP constitutes a promising, novel molecular prescreening tool in mCRC to identify protein expression alterations that may impact on patient outcomes and more precisely guide patient eligibility to clinical trials with novel targeted experimental therapies.

CK7 and consensus molecular subtypes as major prognosticators in V600EBRAF mutated metastatic colorectal cancer

BACKGROUND

^V600EBRAF mutated metastatic colorectal cancer (mCRC) is a subtype (10%) with overall poor prognosis, but the clinical experience suggests a great heterogeneity in survival. It is still unexplored the real distribution of traditional and innovative biomarkers among ^V600EBRAF mutated mCRC and which is their role in the improvement of clinical prediction of survival outcomes.

METHODS

Data and tissue specimens from 155 ^V600EBRAF mutated mCRC patients treated at eight Italian Units of Oncology were collected. Specimens were analysed by means of immunohistochemistry profiling performed on tissue microarrays. Primary endpoint was overall survival (OS).

RESULTS

CDX2 loss conferred worse OS (HR = 1.72, 95%CI 1.03-2.86, p = 0.036), as well as high CK7 expression (HR = 2.17, 95%CI 1.10-4.29, p = 0.026). According to Consensus Molecular Subtypes (CMS), CMS1 patients had better OS compared to CMS2-3/CMS4 (HR = 0.37, 95%CI 0.19-0.71, p = 0.003). Samples showing less TILs had worse OS (HR = 1.72, 95%CI 1.16-2.56, p = 0.007). Progression-free survival analyses led to similar results. At multivariate analysis, CK7 and CMS subgrouping retained their significant correlation with OS.

CONCLUSION

The present study provides new evidence on how several well-established biomarkers perform in a homogenous^V600EBRAF mutated mCRC population, with important and independent information added to standard clinical prognosticators. These data could be useful to inform further translational research, for patients' stratification in clinical trials and in routine clinical practice to better estimate patients' prognosis.

CK7 expression associates with the location, differentiation, lymph node metastasis, and the Dukes' stage of primary colorectal cancers

Purpose: Most colorectal cancers (CRCs) show positive immunohistochemical (IHC) staining for CK20 and negative staining for CK7. However, in clinical settings, some CRCs show positive IHC staining for CK7, and the clinicopathological significance of this needs to be studied. This study investigated the clinicopathological significance of CK7 positivity in CRCs.

Materials and Methods: A total of 178 patients with CRC were used to study the clinicopathological significance of CK7 positivity. Western blotting and immunocytochemical (ICC) staining were used to compare the expression levels of CK7 before and after CoCl₂ treatment.

Results: CK7 expression was associated with the location, differentiation, lymph node metastasis, and the Dukes' stage of CRCs. CK7 positive cells were mainly distributed at the edge of cancer nests, at the invasion front, as single stromal polyploid giant cancer cells (PGCCs), in tumor buds, in intravascular tumor emboli, and in a micropapillary pattern. Results of ICC staining showed that CK7 expression was almost negative in LoVo and HCT116 before CoCl₂ treatment. After CoCl₂ treatment, the PGCCs and their daughter cells of LoVo and HCT116 yielded positive results in CK7 ICC staining. Results of western blotting also confirmed that there was higher CK7 expression in LoVo and HCT116 after CoCl₂ treatment than in the control.

Conclusion: CRC cells expressing CK7 may have strong invasive and metastatic abilities. Some metastasis-related morphological characteristics in CRCs including the invasion front, micropapillary pattern, tumor emboli, and single stromal PGCCs associated with CK7 positive expression.

How the BRAF V600E Mutation Defines a Distinct Subgroup of Colorectal Cancer: Molecular and Clinical Implications

The BRAF oncogene is an integral component of the MAP kinase pathway, and an activating V600E mutation occurs in 15% of sporadic colorectal cancer. This is an early event in serrated pathway tumourigenesis, and the BRAF V600E has been commonly associated with the CpG island methylator phenotype, microsatellite instability (MSI), and a consistent clinical presentation including a proximal location and predilection for elderly females. A proportion of the BRAF mutant lesions remain as microsatellite stable (MSS), and in contrast to the MSI cancers, they have an aggressive phenotype and correlate with poor patient outcomes. Recent studies have found that they have clinical and molecular features of both the BRAF mutant/MSI and the conventional BRAF wild-type cancers and comprise a distinct colorectal cancer subgroup. This review highlights the importance of the BRAF mutation occurring in colorectal cancer stratified for molecular background and discusses its prognostic and clinical significance.

Discovery of Novel and Clinically Relevant Markers in Formalin-Fixed Paraffin-Embedded Esophageal Cancer Specimen

Due to the ineffectiveness of chemoradiation and targeted therapy in esophageal anticancer care and the subsequent low survival rates, we constructed a high throughput method to discover and investigate new markers with prognostic, diagnostic, and therapeutic clinical utility. This was accomplished by developing a quick, inexpensive, and dependable platform to simultaneously quantify thousands of proteins which subsequently revealed novel markers involved in the pathogenesis of esophageal adenocarcinoma (EAC) via discovery mass spectrometry paired with conservative biostatistics. Our method uncovered a perfect storm of tumor suppressors being downregulated, proliferation markers ramped up, and chemoresistance markers overexpressed—many of which could serve as new therapy targets for EAC. The 12 markers discovered by this method are novel regarding their involvement in the pathogenesis of EAC. The molecular oncology arena now has a dozen new proteomic targets suitable for validation and elucidation of their clinical utility via gene knockdown in cellular and animal models. This new method can be replicated and applied to other cancers or disease states for research and development and discovery-based investigations. Our findings, which serve as a proof of concept, will hopefully motivate research groups to further expound on the molecular processes involved in the aggressiveness of EAC and other solid tumor diseases, ultimately leading to improved patient management strategies.

Resveratrol interrupts the pro-invasive communication between cancer associated fibroblasts and cholangiocarcinoma cells

Cholangiocarcinoma (CCA), the cancer arising from the epithelial cells of bile ducts, is a prototype of inflammatory-driven cancer. Cytokines released by cancer associated fibroblasts (CAFs) play a pivotal role in CCA progression, driving the epigenetic Epithelial-to-Mesenchymal transition and the growth and metastasization of CCA cells. Consistently, the conditioned medium from CCA-derived CAFs further stimulated the secretion of IL-6, and to a lesser extent of IL-8, by CCA cells. CCA has a poor prognosis, because of late diagnosis and of high resistance to radio- and chemo-therapy of CCA cells. Targeting the CAFs and their secretion could be an alternative option. We found that while IL-6 indeed promoted the cell migration of invasive CCA cells, the nutraceutical Resveratrol strongly counteracted this effect both in CCA cells and in immortalized cholangiocytes. More importantly, here we show that Resveratrol has the potential to abrogate the secretion of IL-6 by CAFs. While the conditioned medium from CAFs strongly induced IL-6 mediated motility of CCA cells, the conditioned medium from CAFs pre-treated with Resveratrol completely halted cancer cell motility and reverted the N-to E-cadherin switch in migrating cells. This effect was associated with stimulation of autophagy in the cancer cells. This is the first demonstration that CAFs secretory products directly affect the regulation of autophagy and consequently the behavior of CCA cells, and that a nutraceutical may revert the malignant phenotype of cancer cells by acting on CAFs metabolism and secretion.

Altered expression of cytokeratin 7 and CD117 in transitional mucosa adjacent to human colorectal cancer

The multi-step progression of colorectal cancer through precancerous lesions (adenoma and dysplasia) is associated with cumulative molecular alterations, a number of which have also been demonstrated to be present in morphologically normal transitional mucosa adjacent to colorectal cancer. The cytoskeletal protein cytokeratin 7 (CK7) and the receptor tyrosine kinase, KIT proto-oncogene receptor tyrosine kinase (CD117), encoded by the proto-oncogene c-Kit, are lacking in normal colorectal crypt epithelium and are aberrantly expressed in a subset of colorectal cancer. The aim of the present study was to evaluate the expression of CK7 and CD117 in morphologically normal transitional mucosa adjacent to colorectal cancer. Immunohistochemical staining for CK7 and CD117 was performed in the mucosa adjacent to five groups of surgically resected colorectal tumors [low-grade adenoma, high-grade adenoma, mucosal adenocarcinoma, small-sized invasive adenocarcinoma (≤2 cm) and large-sized invasive adenocarcinoma (>2 cm)]. CK7 was expressed in the mucosa adjacent to a subset of colorectal tumors, and the positivity ratio increased according to tumor grade from low-grade adenoma up to small-sized invasive adenocarcinoma (61.2%). However, the positivity ratio of CK7 in the mucosa adjacent to the large-sized invasive adenocarcinoma (25.0%) was significantly lower compared with that of the next lower grade. CD117 was also expressed in the mucosa adjacent to a subset of colorectal tumors. In contrast to CK7, the positivity ratio of CD117 increased according to tumor grade from low-grade adenoma all the way through to the large-sized invasive adenocarcinoma (45.0%). Based on these results, the mechanism of CK7 and CD117 expression in the transitional mucosa adjacent to colorectal cancer may be different, and analysis of their individual expression may provide novel insights into the development and progression of colorectal cancer.

MUC1, MUC2, MUC5AC, and MUC6 in colorectal cancer: expression profiles and clinical significance

Mucin glycoprotein expression can be altered during the carcinogenic process. The impact on the prognosis of patients with colorectal cancer (CRC) is controversial. We analyzed tumors from 381 patients for MUC1, MUC2, MUC5AC, and MUC6 expression by immunohistochemical staining, using tissue microarrays. Progression-free and cancer-specific survival were determined using the Kaplan-Meier method. Expression of intestinal mucin MUC2 was lost in 85 (23 %) CRCs, and patients with MUC6-negative tumors showed shorter progression-free survival (PFS, p = 0.043). Gastric mucins MUC5AC and MUC6 showed high (>50 %) aberrant expression in 28 (8 %) and 9 (2 %) cases, respectively. High expression of MUC5AC was associated with longer PFS (p = 0.055). High expression of MUC6 was associated with 100 % PFS (p = 0.024) and longer cancer-specific survival (CSS, p = 0.043). MUC1 was expressed in 238 (64 %) tumors and had no impact on outcome. When analysis was restricted to stages II and III, loss of MUC2 was associated with adverse outcome. Overexpression of both MUC5AC and MUC6 significantly predicted favorable PFS and CSS. In conclusion, loss of MUC2 expression proved to be a predictor of adverse outcome, while the gain of aberrant expression of MUC5AC and particularly of MUC6 was associated with favorable outcome in CRC, notably in intermediate stages II and III.

Lymph node retrieval in colorectal cancer: determining factors and prognostic significance

PURPOSE

The study aimed to analyze clinicopathological factors that determine the extent of lymph node retrieval and to evaluate its prognostic impact in patients with colorectal cancer (CRC).

METHODS

The number of retrieved lymph nodes was analyzed in 381 CRC specimens. Lymph node count was related to different clinicopathological variables by binary logistic regression. Progression-free survival (PFS) and cancer-specific survival (CSS) were determined using the Kaplan-Meier method and Cox regression models.

RESULTS

The median number of retrieved lymph nodes was 20 (mean 21 ± 10, range 1-65) in right-sided, 13 (16 ± 10, 1-66) in left-sided, and 15 (18 ± 11, 3-64) in rectal tumors. The number of retrieved lymph nodes was independently associated with T-classification (p < 0.001), N-classification (p = 0.014), and tumor size (p = 0.005) as well as right-sided tumor location (p = 0.012). There was no association with age, sex, tumor grade, mismatch-repair status, and lymph or blood vessel invasion. The longer the surgical specimen, the higher were the numbers of retrieved and positive lymph nodes (p < 0.001, respectively). In patients with locally advanced (T3/T4) tumors (n = 283), analysis of more than 12 lymph nodes was independently associated with PFS (HR = 0.63, p = 0.025) and CSS (HR = 0.54, p = 0.004). In the subset of T3/T4 N0 patients (n = 130), analysis of more than 12 lymph nodes similarly proved to be an independent predictor of outcome (PFS, HR = 0.48, p = 0.046; OS, HR = 0.41, p = 0.026).

CONCLUSION

The number of retrieved lymph nodes is associated with higher tumor stage, tumor size, and right-sided location. Low lymph node count indicates adverse outcome in patients with locally advanced (T3/T4) disease.

Long non-coding antisense RNA KRT7-AS is activated in gastric cancers and supports cancer cell progression by increasing KRT7 expression

Alterations in long non-coding RNAs (lncRNAs) are associated with human carcinogenesis. One group of lncRNAs, which are antisense in orientation to coding mRNAs (ASs), have been recently described in cancers but are poorly understood. We sought to identify ASs involved in human gastric cancer (GC) and to elucidate their mechanisms of action in carcinogenesis. We performed massively parallel RNA sequencing in GCs and matched normal tissues, as well as in GC-derived and normal gastric epithelial cell lines. One AS, designated Homo sapiens keratin 7 (KRT7-AS), was selected due to its marked upregulation and concordant expression with its cognate sense counterpart, KRT7, in GC tissues and cell lines. KRT7-AS formed an RNA-RNA hybrid with KRT7 and controlled KRT7 expression at both the mRNA and the post-transcriptional levels. Moreover, forced overexpression of the KRT7-overlapping region (OL) of KRT7-AS (but not its non-KRT7-OL portions) increased keratin 7 protein levels in cells. Finally, forced overexpression of full-length KRT7-AS or OL KRT7-AS (but not its non-KRT7-OL regions) promoted GC cell proliferation and migration. We conclude that lncRNA KRT7-AS promotes GC, at least in part, by increasing KRT7 expression.

Molecular and pathogenetic aspects of tumor budding in colorectal cancer

In recent years, tumor budding in colorectal cancer has gained much attention as an indicator of lymph node metastasis, distant metastatic disease, local recurrence, worse overall and disease-free survival, and as an independent prognostic factor. Tumor buds, defined as the presence of single tumor cells or small clusters of up to five tumor cells at the peritumoral invasive front (peritumoral buds) or within the main tumor body (intratumoral buds), are thought to represent the morphological correlate of cancer cells having undergone epithelial–mesenchymal transition (EMT), an important mechanism for the progression of epithelial cancers. In contrast to their undisputed prognostic power and potential to influence clinical management, our current understanding of the biological background of tumor buds is less established. Most studies examining tumor buds have attempted to recapitulate findings of mechanistic EMT studies using immunohistochemical markers. The aim of this review is to provide a comprehensive summary of studies examining protein expression profiles of tumor buds and to illustrate the molecular pathways and crosstalk involved in their formation and maintenance.

Characterization of protein marker expression, tumorigenicity, and doxorubicin chemoresistance in two new canine mammary tumor cell lines

Background

Canine mammary tumors (CMTs) are the most common type of cancer found in female dogs. Establishment and evaluation of tumor cell lines can facilitate investigations of the biological mechanisms of cancer. Different cell models are used to investigate genetic, epigenetic, and cellular pathways, cancer progression, and cancer therapeutics. Establishment of new cell models will greatly facilitate research in this field. In the present study, we established and characterized two new CMT cell lines derived from a single CMT.

Results

We established two cell lines from a single malignant CMT specimen: DTK-E and DTK-SME. Morphologically, the DTK-E cells were large, flat, and epithelial-like, whereas DTK-SME cells were round and epithelial-like. Doubling times were 24 h for DTK-E and 18 h for DTK-SME. On western blots, both cell lines expressed cytokeratin AE1, vimentin, cytokeratin 7 (CK7), and heat shock protein 27 (HSP27). Moreover, investigation of chemoresistance revealed that DTK-SME was more resistant to doxorubicin-induced apoptosis than DTK-E was. After xenotransplantation, both DTK-E and DTK-SME tumors appeared within 14 days, but the average size of DTK-SME tumors was greater than that of DTK-E tumors after 56 days.

Conclusion

We established two new cell lines from a single CMT, which exhibit significant diversity in cell morphology, protein marker expression, tumorigenicity, and chemoresistance. The results of this study revealed that the DTK-SME cell line was more resistant to doxorubicin-induced apoptosis and exhibited higher tumorigenicity in vivo than the DTK-E cell line. We anticipate that the two novel CMT cell lines established in this study will be useful for investigating the tumorigenesis of mammary carcinomas and for screening anticancer drugs.

Prognostic stratification of colorectal cancer patients: current perspectives

Tumor staging according to the American Joint Committee on Cancer/Union for International Cancer Control tumor, node, metastasis (TNM) system is currently regarded as the standard for staging of patients with colorectal cancer. This system provides the strongest prognostic information for patients with early stage disease and those with advanced disease. For patients with intermediate levels of disease, it is less able to predict disease outcome. Therefore, additional prognostic markers are needed to improve the management of affected patients. Ideal markers are readily assessable on hematoxylin and eosin-stained tumor slides, and in this way are easily applicable worldwide. This review summarizes the histological features of colorectal cancer that can be used for prognostic stratification. Specifically, we refer to the different histological variants of colorectal cancer that have been identified, each of these variants carrying distinct prognostic significance. Established markers of adverse outcomes are lymphatic and venous invasion, as well as perineural invasion, but underreporting still occurs in the routine setting. Tumor budding and tumor necrosis are recent advances that may help to identify patients at high risk for recurrence. The prognostic significance of the antitumor inflammatory response has been known for quite a long time, but a lack of standardization prevented its application in routine pathology. However, scales to assess intra- and peritumoral inflammation have recently emerged, and can be expected to strengthen the prognostic significance of the pathology report.

BRAF-mutated microsatellite stable colorectal carcinoma: an aggressive adenocarcinoma with reduced CDX2 and increased cytokeratin 7 immunohistochemical expression

Reduced CDX2 and cytokeratin 20 (CK20) expression in colorectal carcinoma with BRAF mutation and high-level microsatellite instability (MSI-H) has been well documented. The immunophenotype of BRAF-mutated microsatellite stable (MSS) colorectal carcinoma has not been reported. We analyzed 205 colorectal carcinomas including 28 BRAF-mutated MSS, 53 BRAF-mutated MSI-H, and 124 BRAF wild-type MSS tumors for CDX2, cytokeratin 7 (CK7), and CK20 immunohistochemical expression. CDX2 was scored semiquantitatively for both staining intensity and percent of tumor cells staining and a modified CDX2 H-score was calculated. Patients with BRAF-mutated MSS colorectal carcinomas were more frequently stage IV at presentation compared to patients with BRAF-mutated MSI-H colorectal carcinomas and BRAF wild-type MSS colorectal carcinomas (32% versus 8% versus 15%, P < .001). BRAF-mutated MSS colorectal carcinoma displayed reduced CDX2 expression compared to BRAF wild-type MSS colorectal carcinoma (75% versus 94%; mean CDX2 H-score 98 versus 150, P < .001). CK7 expression was more often identified in BRAF-mutated MSS colorectal carcinoma compared to both BRAF-mutated MSI-H colorectal carcinoma and BRAF wild-type MSS colorectal carcinoma (39% versus 6% versus 6%, P = .0001). BRAF-mutated MSI-H colorectal carcinomas were less often CK20 positive compared to BRAF-mutated MSS and BRAF wild-type MSS tumors (70% versus 93% versus 90%, P = 0.001). In summary, BRAF-mutated MSS colorectal carcinoma often displays reduced CDX2 and increased CK7 expression. Knowledge of this altered immunophenotype is important as patients with BRAF-mutated MSS colorectal carcinoma often present with metastatic disease and the altered tumor immunophenotype may lead to the erroneous assumption that origin from the colon/rectum is unlikely.

Keloid-derived keratinocytes exhibit an abnormal gene expression profile consistent with a distinct causal role in keloid pathology

Keloids are disfiguring scars that extend beyond the original wound borders and resist treatment. Keloids exhibit excessive extracellular matrix deposition, although the underlying mechanisms remain unclear. To better understand the molecular basis of keloid scarring, here we define the genomic profiles of keloid fibroblasts and keratinocytes. In both cell types, keloid-derived cells exhibit differential expression of genes encompassing a diverse set of functional categories. Strikingly, keloid keratinocytes exhibited decreased expression of a set of transcription factor, cell adhesion, and intermediate filament genes essential for normal epidermal morphology. Conversely, they exhibit elevated expression of genes associated with wound healing, cellular motility, and vascular development. A substantial number of genes involved in epithelial-mesenchymal transition were also up-regulated in keloid keratinocytes, implicating this process in keloid pathology. Furthermore, keloid keratinocytes displayed significantly higher migration rates than normal keratinocytes in vitro and reduced expression of desmosomal proteins in vivo. Previous studies suggested that keratinocytes contribute to keloid scarring by regulating extracellular matrix production in fibroblasts. Our current results show fundamental abnormalities in keloid keratinocytes, suggesting they have a profoundly more direct role in keloid scarring than previously appreciated. Therefore, development of novel therapies should target both fibroblast and keratinocyte populations for increased efficacy.