Expression of the intestinal biomarkers Guanylyl cyclase C and CDX2 in poorly differentiated colorectal carcinomas

Homeobox Gene Expression Dysregulation as Potential Diagnostic and Prognostic Biomarkers in Bladder Cancer

Homeobox genes serve as master regulatory transcription factors that regulate gene expression during embryogenesis. A homeobox gene may have either tumor-promoting or tumor-suppressive properties depending on the specific organ or cell lineage where it is expressed. The dysregulation of homeobox genes has been reported in various human cancers, including bladder cancer. The dysregulated expression of homeobox genes has been associated with bladder cancer clinical outcomes. Although bladder cancer has high risk of tumor recurrence and progression, it is highly challenging for clinicians to accurately predict the risk of tumor recurrence and progression at the initial point of diagnosis. Cystoscopy is the routine surveillance method used to detect tumor recurrence. However, the procedure causes significant discomfort and pain that results in poor surveillance follow-up amongst patients. Therefore, the development of reliable non-invasive biomarkers for the early detection and monitoring of bladder cancer is crucial. This review provides a comprehensive overview of the diagnostic and prognostic potential of homeobox gene expression dysregulation in bladder cancer.

Diagnostic and Prognostic Roles of CDX2 Immunohistochemical Expression in Colorectal Cancers

The study is aimed to evaluate the diagnostic and prognostic role of the immunohistochemical expression of the Caudal-type homeobox transcription factor 2 (CDX2) in colorectal cancers (CRCs) through a meta-analysis. By searching relevant databases, 38 articles were eligible to be included in this study. We extracted the information for CDX2 expression rates and the correlation between CDX2 expression and clinicopathological characteristics. The estimated rates of CDX2 expression were 0.882 [95% confidence interval (CI) 0.774−0.861] and 0.893 (95% CI 0.820−0.938) in primary and metastatic CRCs, respectively. Furthermore, based on their histologic subtype, CDX2 expression rates of adenocarcinoma and medullary carcinoma were 0.886 (95% CI 0.837−0.923) and 0.436 (95% CI 0.269−0.618), respectively. There was a significant difference in CDX2 expression rates between adenocarcinoma and medullary carcinoma in the meta-regression test (p < 0.001). In addition, CDX2 expression was significantly lower in CRCs with the BRAFV600E mutation than in CRCs without mutation. Patients with CDX2 expression had better overall and cancer-specific survival rates than those without CDX2 expression. Thus, CDX2 is a useful diagnostic and prognostic marker CRCs.

Deep Learning Models for Poorly Differentiated Colorectal Adenocarcinoma Classification in Whole Slide Images Using Transfer Learning

Colorectal poorly differentiated adenocarcinoma (ADC) is known to have a poor prognosis as compared with well to moderately differentiated ADC. The frequency of poorly differentiated ADC is relatively low (usually less than 5% among colorectal carcinomas). Histopathological diagnosis based on endoscopic biopsy specimens is currently the most cost effective method to perform as part of colonoscopic screening in average risk patients, and it is an area that could benefit from AI-based tools to aid pathologists in their clinical workflows. In this study, we trained deep learning models to classify poorly differentiated colorectal ADC from Whole Slide Images (WSIs) using a simple transfer learning method. We evaluated the models on a combination of test sets obtained from five distinct sources, achieving receiver operating characteristic curve (ROC) area under the curves (AUCs) up to 0.95 on 1799 test cases.

Predictors of Metachronous Risk Polyps After Index Colonoscopy

INTRODUCTION

Guidelines for surveillance after polypectomy are lacking in strong evidence. Our aim was to identify some precursors of colorectal cancer lesions at 3 years after polypectomy to improve stratification and surveillance programs.

METHODS

We included patients with high-risk lesions (HRLs), defined as advanced adenoma (AA), large serrated polyps (SPs), and multiplicity (≥3 of any adenomas/SPs). Data on age, sex, cardiovascular risk factors, pharmacological treatment, and the histological characteristics in each individual, and mutations in genes involved in the most advanced index polyp, were collected. Parameters independently associated with a metachronous HRL diagnosis were evaluated through univariate and multivariate analyses. The results are reported as odds ratios and 95% confidence intervals along with P values.

RESULTS

A total of 537 cases (median age: 60.7 years; 66% male) were included. Dyslipidemia and smoking correlated with metachronous HRLs. Multivariate logistic regression analysis showed that the presence of multiplicity with ≥3 polyps on the index colonoscopy was significantly associated with metachronous HRL, AA, proximal AA, and ≥3 polyps at 3 years. In addition, independent predictors of metachronous proximal AA were increasing age, female sex, and the loss of expression of the MLH1 protein.

DISCUSSION

Multiplicity was a strong predictor of HRLs at 3 years, although the inclusion of other clinical variables (age, sex, smoking status, and dyslipidemia) improves surveillance recommendations. Without these risk factors, the surveillance could be extended to 5 years; we propose examining the somatic expression of MHL1 in all patients.

Preclinical Antitumor Activity and Biodistribution of a Novel Anti-GCC Antibody-Drug Conjugate in Patient-derived Xenografts

Guanylyl cyclase C (GCC) is a unique therapeutic target with expression restricted to the apical side of epithelial cell tight junctions thought to be only accessible by intravenously administered agents on malignant tissues where GCC expression is aberrant. In this study, we sought to evaluate the therapeutic potential of a second-generation investigational antibody-dug conjugate (ADC), TAK-164, comprised of a human anti-GCC mAb conjugated via a peptide linker to the highly cytotoxic DNA alkylator, DGN549. The in vitro binding, payload release, and in vitro activity of TAK-164 was characterized motivating in vivo evaluation. The efficacy of TAK-164 and the relationship to exposure, pharmacodynamic marker activation, and biodistribution was evaluated in xenograft models and primary human tumor xenograft (PHTX) models. We demonstrate TAK-164 selectively binds to, is internalized by, and has potent cytotoxic effects against GCC-expressing cells in vitro A single intravenous administration of TAK-164 (0.76 mg/kg) resulted in significant growth rate inhibition in PHTX models of metastatic colorectal cancer. Furthermore, imaging studies characterized TAK-164 uptake and activity and showed positive relationships between GCC expression and tumor uptake which correlated with antitumor activity. Collectively, our data suggest that TAK-164 is highly active in multiple GCC-positive tumors including those refractory to TAK-264, a GCC-targeted auristatin ADC. A strong relationship between uptake of ⁸⁹Zr-labeled TAK-164, levels of GCC expression and, most notably, response to TAK-164 therapy in GCC-expressing xenografts and PHTX models. These data supported the clinical development of TAK-164 as part of a first-in-human clinical trial (NCT03449030).

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Silencing the GUCA2A-GUCY2C tumor suppressor axis in CIN, serrated, and MSI colorectal neoplasia

Colorectal cancers (CRCs) initiate through distinct mutations, including in APC pathway components leading to tubular adenomas (TAs); in BRAF, with epigenetic silencing of CDX2, leading to serrated adenomas (SAs); and in the DNA mismatch repair machinery driving microsatellite instability (MSI). Transformation through the APC pathway involves loss of the hormone GUCA2A that silences the tumor-suppressing receptor GUCY2C. Indeed, oral hormone replacement is an emerging strategy to reactivate GUCY2C and prevent CRC initiation and progression. Moreover, retained expression by tumors arising from TAs has established GUCY2C as a diagnostic and therapeutic target to prevent and treat metastatic CRC. Here, we defined the potential role of the GUCA2A-GUCY2C axis and its suitability as a target in tumors arising through the SA and MSI pathways. GUCA2A hormone expression was eliminated in TAs, SAs, and MSI tumors compared to their corresponding normal adjacent tissues. In contrast to the hormone, the tumor-suppressing receptor GUCY2C was retained in TA and MSI tumors. Surprisingly, GUCY2C expression was nearly eliminated in SAs, reflecting loss of the transcription factor CDX2. Changes in the GUCA2A-GUCY2C axis in human SAs and MSI tumors were precisely recapitulated in genetic mouse models. These data reveal the possibility of GUCA2A loss silencing GUCY2C in the pathophysiology of, and oral hormone replacement to restore GUCY2C signaling to prevent, MSI tumors. Also, they highlight the potential for targeting GUCY2C to prevent and treat metastases arising from TA and MSI tumors. In contrast, loss of GUCY2C excludes patients with SAs as candidates for GUCY2C-based prevention and therapy.

TAK-264 (MLN0264) in Previously Treated Asian Patients with Advanced Gastrointestinal Carcinoma Expressing Guanylyl Cyclase C: Results from an Open-Label, Non-randomized Phase 1 Study

PURPOSE

This phase 1 dose-escalation portion of the study evaluated the safety, pharmacokinetics (PK), and antitumor activity of TAK-264 in Asian patients with advanced gastrointestinal (GI) carcinoma or metastatic or recurrent gastric or gastroesophageal junction adenocarcinoma expressing guanylyl cyclase C (GCC).

MATERIALS AND METHODS

Adult patients with advanced GI malignancies expressing GCC (H-score ≥ 10) received TAK-264 on day 1 of 3-week cycles as 30-minute intravenous infusions for up to 1 year or until disease progression or unacceptable toxicity. The primary objectives were to evaluate the safety profile including dose-limiting toxicities (DLTs) during cycle 1, determine the maximum tolerated dose (MTD), and characterize the PK profile of TAK-264.

RESULTS

Twelve patients were enrolled and treated with 1.2 mg/kg (n=3), 1.5 mg/kg (n=3), or 1.8 mg/kg TAK-264 (n=6). Median number of treatment cycles received was two (range, 1 to 10). None of the patients experienced a DLT and the MTD was not determined. Ten patients (83%) experienced adverse events (AEs). The most common were neutropenia, anorexia, and nausea (each reported by four patients). Five patients (42%) experienced grade ≥ 3 AEs consisting of tumor hemorrhage and hypertension, ascites, adrenal insufficiency, neutropenia and asthenia. Serum exposure to TAK-264 increased proportionally with the dose and the median half-life was approximately 5.5-6.6 days. No patients experienced an objective response.

CONCLUSION

TAK-264 demonstrated a manageable safety profile with limited antitumor activity consistent with studies conducted in Western patients with advanced GI malignancies. TAK-264 exposure increased proportionally with the dose.

A monomethyl auristatin E-conjugated antibody to guanylyl cyclase C is cytotoxic to target-expressing cells in vitro and in vivo

Guanylyl cyclase C (GCC) is a cell-surface protein that is expressed by normal intestinal epithelial cells, more than 95% of metastatic colorectal cancers (mCRC), and the majority of gastric and pancreatic cancers. Due to strict apical localization, systemically delivered GCC-targeting agents should not reach GCC in normal intestinal tissue, while accessing antigen in tumor. We generated an investigational antibody-drug conjugate (TAK-264, formerly MLN0264) comprising a fully human anti-GCC monoclonal antibody conjugated to monomethyl auristatin E via a protease-cleavable peptide linker. TAK-264 specifically bound, was internalized by, and killed GCC-expressing cells in vitro in an antigen-density-dependent manner. In GCC-expressing xenograft models with similar GCC expression levels/patterns observed in human mCRC samples, TAK-264 induced cell death, leading to tumor regressions and long-term tumor growth inhibition. TAK-264 antitumor activity was generally antigen-density-dependent, although some GCC-expressing tumors were refractory to TAK-264-targeted high local concentrations of payload. These data support further evaluation of TAK-264 in the treatment of GCC-expressing tumors.

A phase II study of antibody-drug conjugate, TAK-264 (MLN0264) in previously treated patients with advanced or metastatic pancreatic adenocarcinoma expressing guanylyl cyclase C

Background This phase II open-label, multicenter study evaluated the efficacy, safety, and tolerability of TAK-264 in previously treated patients with advanced or metastatic pancreatic adenocarcinoma expressing guanylyl cyclase C (GCC). Methods Patients with advanced or metastatic pancreatic adenocarcinoma expressing GCC (H-score ≥ 10) received TAK-264 1.8 mg/kg on day 1 of a 21-day cycle as a 30-min intravenous infusion for up to 1 year or until disease progression or unacceptable toxicity. The primary objective was overall response rate (ORR [complete response + partial response (PR)]). Secondary objectives included evaluations of the safety and pharmacokinetic profile of TAK-264 (NCT02202785). Results 43 patients were enrolled and treated with 1.8 mg/kg TAK-264: 11, 15, and 17 patients with low, intermediate, and high GCC expression, respectively. Median number of treatment cycles received was two (range 1-10). The ORR was 3%, including one patient with intermediate GCC expression who achieved a PR. All patients experienced ≥1 adverse events (AE). The majority of patients experienced grade 1/2 AEs affecting the gastrointestinal tract. Fifteen (35%) patients experienced ≥grade 3 drug-related AEs; five (12%) patients had a serious AE. The most common (≥10% of patients) all-grade drug-related AEs were nausea (33%), fatigue (28%), neutropenia (23%), decreased appetite (23%), vomiting (16%), asthenia (16%), and alopecia (14%). Conclusions TAK-264 demonstrated a manageable safety profile; however, the low efficacy of TAK-264 observed in this study did not support further clinical investigation.

CDX2: Linking Cell and Patient Fates in Colon Cancer

Administering adjuvant chemotherapy to stage II colon cancer patients is controversial due to limited benefit observed for this subpopulation. Recently, Dalerba et al. (2016) identified a subgroup of stage II patients that might benefit from adjuvant chemotherapy based on lack of CDX2 expression in their cancer stem cells.

A Pilot Study of CK19, CK20 and GCC mRNA in the Peripheral Blood as a Colorectal Cancer Biomarker Panel

Colorectal cancer remains one of the major cancer- related deaths despite progress in the treatment during past decades. Detection of disease at earlier stages reduces its mortality. The aim of current study was to investigate expression of Cytokeratin 19 (CK19), Cytokeratin 20 (CK20) and Guanylyl Cyclase C (GCC) mRNA in peripheral blood of non- metastatic colorectal cancer patients which may result into introducing of an early detection test. 25 patients with colorectal cancer and 25 healthy controls were recruited. Blood was obtained from all individuals. Expression of CK19 and CK20 and GCC mRNA and 18SrRNA (as reference gene) were determined based on real- time RT-PCR on total RNA from blood. CK19, CK20 and GCC expression had been detected in 68%, 76% & 52% of patient group, respectively, which was higher than healthy group, with 8%, 32% and 0% expression, respectively (p<0.05). CK20 was over-expressed 8- fold more in patients compared to controls. Similar result was found for CK19 with 4- fold over- expression. Sensitivity and specificity of combination of markers were 88% and 68%, respectively. Current data suggest that the detection of CK20 & CK19 as relative sensitive markers may become a valuable tool for primary diagnosis of colorectal cancer in early stages. GCC could be considered as a specific tumor marker for detection of colorectal cancer. Higher expression of these markers in patients may be considered as a relative good tool for the diagnosis of disease in non- metastatic stages.

The clinical perspectives of CDX2 expression in colorectal cancer: a qualitative systematic review

INTRODUCTION

Homeobox genes are often deregulated in cancer. They can have both oncogenic and tumor-suppressing potential. The Caudal-related homeobox transcription factor 2 (CDX2) is an intestine-specific transcription factor. It is implicated in differentiation, proliferation, cell-adhesion, and migration. CDX2 has been proposed as a tumor suppressor in colorectal cancer but its role is still controversial. This systematic review were undertaken in order to clarify CDX2s role in colorectal cancer.

METHODS

A literature search was performed in the MEDLINE database from 1966 to February 2014. Only studies in which all or a part of the experimental design were performed on human colorectal cancer tissue were included. Thus, studies solely performed in cell-lines or animal models were excluded.

RESULTS

Fifty-two articles of relevance were identified. CDX2 expression was rarely lost in colorectal cancers, however the expression pattern may often be heterogeneous within the tumor and can be selectively down regulated at the invasive front and in tumor buddings. Loss of CDX2 expression is probably correlated to tumor grade, stage, right-sided tumor location, MMR-deficiency, CIMP, and BRAF mutations. The CDX2 gene is rarely mutated but the locus harboring the gene is often amplified and may suggest CDX2 as a linage-survival oncogene. CDX2 might be implicated in cell proliferation and migration through cross-talk with the Wnt-signaling pathway, tumor-stroma proteins, and inflammatory cytokines.

CONCLUSION

A clear role for CDX2 expression in colorectal cancer remains to be elucidated, and it might differ in relation to the underlying molecular pathways leading to the cancer formation.

Current status of gene expression profiling to assist decision making in stage II colon cancer

The decision regarding adjuvant therapy for patients with stage II colon cancer remains a challenge. In contrast to stage III colon cancer, for which compelling clinical data support the use of adjuvant chemotherapy, the clinical benefit of systemic therapy in unselected patients with stage II disease is modest at best. Risk stratification based on clinicopathologic features and DNA mismatch repair status is commonly used in adjuvant therapy decisions, but these factors do not have a desired level of precision in identifying patients at high risk. Recently, gene expression platforms have been developed to further define risk and to assist in therapeutic decision making for patients with stage II disease. This review describes those platforms that are furthest along in clinical development, in an effort to place their potential clinical application in context.

The stem cell marker CD133 is highly expressed in sessile serrated adenoma and its borderline variant compared with hyperplastic polyp

Non-dysplastic serrated polyps (ND-SP) represent a heterogeneous group of colorectal lesions that comprise hyperplastic polyp (HP) and the non-dysplastic subset of sessile serrated adenoma/polyp/lesion (SSA/P/L) and its borderline variant (BSSA/P/L). Given the observer variation in their histological typing, the identification of reliable markers that assist in the characterisation is warranted. Most important is the identification of polyp qualities that may reflect the patients' risk of developing colorectal cancer. To address these issues, CD133 may represent a potential adjunct. Here we studied the discriminatory value of CD133 expression in the classification of ND-SPs and its distribution pattern in relation to synchronous colorectal carcinoma (SCRC). 39 SSA/P/Ls, 27 BSSA/P/Ls and 21 matched HPs were immunostained for CD133. The data were further correlated to the presence of SCRC and to polyp site and size. Ignoring SCRC status, CD133 was expressed more prominently in SSA/P/Ls than in HPs. The values for BSSA/P/Ls fell in between, yet closer to the SSA/P/L scorings. This observation was retained in the context of SCRC and for SSA/P/Ls not associated with SCRC. Right-sidedness and large size of the polyps more commonly associated with increased CD133 expression. CD133 expression was not a significant discriminator as to the SCRC status. BSSA/P/Ls are more closely aligned to SSA/P/L and further that SSA/P/L and BSSA/P/Ls fundamentally differ from HP by their CD133 immunoprofile, a notion that can be exploited in the diagnostic routine practice. Recorded data further indirectly support the idea that SSA/P/Ls are more prone to neoplastic progression than are HPs.

Transmembrane guanylate cyclase in intestinal pathophysiology

PURPOSE OF REVIEW

Production of cyclic guanosine monophosphate (cGMP) by guanylate cyclase is of critical importance to gastrointestinal physiology. Tight regulation of cGMP concentration is necessary for proper intestinal secretion and intestinal epithelial cell proliferative and apoptotic homeostasis. This review focuses on recent work detailing the role of a subset of transmembrane guanylate cyclases in the pathophysiology of intestinal secretory and motility disorders and intestinal epithelial cell transformation. Also considered is the potential for therapeutic manipulation of intestinal guanylate cyclase/cGMP signaling for the correction of chronic constipation and gastrointestinal cancer.

RECENT FINDINGS

Recent work in mice and humans suggests a role for transmembrane guanylate cyclases in intestinal fluid secretion as well as hormonal enteric-renal signaling which mediates postprandial natriuresis. Transmembrane guanylate cyclases are also important in gastrointestinal transit rate and motility. Ongoing clinical trials have found that guanylate cyclase activating peptides are safe and effective in the treatment of constipation-predominant irritable bowel syndrome and chronic constipation. In addition, accumulating evidence indicates that membrane-associated guanylate cyclase receptors regulate intestinal epithelial cell homeostatic proliferation and apoptosis as well as gastrointestinal malignancy. The anticancer activity of cGMP signaling in animal studies suggests additional therapeutic applications for guanylate cyclase agonists.

SUMMARY

Progress toward understanding gastrointestinal transmembrane guanylate cyclase/cGMP physiology has recently accelerated due to definitive in-vitro studies and work using gene-targeted animal models and has facilitated the development of safe and effective drugs designed to regulate cGMP production in the intestine. Current work should be directed toward a detailed understanding of cGMP effector pathways and the manner in which subcellular concentrations of cGMP regulate them to influence intestinal health and disease.

Radiometallated peptides targeting guanylate cyclase C and the urokinase-type plasminogen activator receptor

Research is currently underway worldwide into the development of receptor-specific radiopharmaceuticals for the imaging and treatment of cancer. The successful clinical development of radiolabeled somatostatin analogs for imaging and treatment of cancers overexpressing somatostatin receptors has catalyzed further preclinical investigation of other radiolabeled peptides for molecular imaging and peptide-receptor radiotherapy, including such well-studied peptide vectors as cholecystokinin, neurotensin, bombesin and RGD peptides. Within this larger context, this article will focus on the current status of two more recent additions to the list of molecular imaging targets – guanylate cyclase C, a specific marker for colorectal cancer, and the urokinase plasminogen activator receptor, a cell-surface receptor overexpressed in diverse cancer types.