NDRG1 enhances the sensitivity of cetuximab by modulating EGFR trafficking in colorectal cancer

N6-methyladenosine methylation analysis of long noncoding RNAs and mRNAs in 5-FU-resistant colon cancer cells

N6 methyladenosine (m6A), methylation at the sixth N atom of adenosine, is the most common and abundant modification in mammalian mRNAs and non-coding RNAs. Increasing evidence shows that the alteration of m6A modification level could regulate tumour proliferation, metastasis, self-renewal, and immune infiltration by regulating the related expression of tumour genes. However, the role of m6A modification in colorectal cancer (CRC) drug resistance is unclear. Here, MeRIP-seq and RNA-seq techniques were utilized to obtain mRNA, lncRNA expression, and their methylation profiles in 5-Fluorouracil (5-FU)-resistant colon cancer HCT-15 cells and control cells. In addition, we performed detailed bioinformatics analysis as well as in vitro experiments of lncRNA to explore the function of lncRNA with differential m6A in CRC progression and drug resistance. In this study, we obtained the m6A methylomic landscape of CRC cells and resistance group cells by MeRIP-seq and RNA-seq. We identified 3698 differential m6A peaks, of which 2224 were hypermethylated, and 1474 were hypomethylated. Among the lncRNAs, 60 were hypermethylated, and 38 were hypomethylated. GO and KEGG analysis annotations showed significant enrichment of endocytosis and MAPK signalling pathways. Moreover, knockdown of lncRNA ADIRF-AS1 and AL139035.1 promoted CRC proliferation and invasive metastasis in vitro. lncRNA- mRNA network showed that ADIRF-AS1 and AL139035.1 May play a key role in regulating drug resistance formation. We provide the first m6A methylation profile in 5-FU resistance CRC cells and analyse the functions of differential m6A-modified mRNAs and lncRNAs. Our results indicated that differential m6A RNAs were significantly associated with MAPK signalling and endocytosis after induction of 5-FU resistance. Knockdown of LncRNA ADIRF-AS1 and AL139035.1 promotes CRC progression and might be critical in regulating drug resistance formation.

SIRT6 Inhibits Anoikis of Colorectal Cancer Cells by Down-Regulating NDRG1

Anoikis, a form of apoptosis resulting from the loss of cell-extracellular matrix interaction, is a significant barrier to cancer cell metastasis. However, the epigenetic regulation of this process remains to be explored. Here, we demonstrate that the histone deacetylase sirtuin 6 (SIRT6) plays a pivotal role in conferring anoikis resistance to colorectal cancer (CRC) cells. The protein level of SIRT6 is negatively correlated with anoikis in CRC cells. The overexpression of SIRT6 decreases while the knockdown of SIRT6 increases detachment-induced anoikis. Mechanistically, SIRT6 inhibits the transcription of N-myc downstream-regulated gene 1 (NDRG1), a negative regulator of the AKT signaling pathway. We observed the up-regulation of SIRT6 in advanced-stage CRC samples. Together, our findings unveil a novel epigenetic program regulating the anoikis of CRC cells.

Protein post-translational modifications: A key factor in colorectal cancer resistance mechanisms

Colorectal cancer (CRC) is one of the leading causes of cancer-related death. Despite advances in treatment, drug resistance remains a critical impediment. Post-translational modifications (PTMs) regulate protein stability, localization, and activity, impacting vital cellular processes. Recent research has highlighted the essential role of PTMs in the development of CRC resistance. This review summarizes recent advancements in understanding PTMs' roles in CRC resistance, focusing on the latest discoveries. We discuss the functional impact of PTMs on signaling pathways and molecules involved in CRC resistance, progress in drug development, and potential therapeutic targets. We also summarize the primary enrichment methods for PTMs. Finally, we discuss current challenges and future directions, including the need for more comprehensive PTM analysis methods and PTM-targeted therapies. This review identifies potential therapeutic interventions for addressing medication resistance in CRC, proposes prospective therapeutic options, and gives an overview of the function of PTMs in CRC resistance.

Translational research of new developments in targeted therapy of colorectal cancer

A severe global health concern is the rising incidence and mortality rate of colorectal cancer (CRC). Chemotherapy, which is typically used to treat CRC, is known to have limited specificity and can have noticeable side effects. A paradigm shift in cancer treatment has been brought about by the development of targeted therapies, which has led to the appearance of pharmacological agents with improved efficacy and decreased toxicity. Epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), and BRAF are among the molecular targets covered in this review that are used in targeted therapy for CRC. The current discussion also covers advancements in targeted therapeutic approaches, such as antibody-drug conjugates, immune checkpoint inhibitors, and chimeric antigen receptor (CAR) T-cell therapy. A review of the clinical trials and application of these particular therapies in treating CRC is also done. Despite the improvements in targeted therapy for CRC, problems such as drug resistance and patient selection remain to be solved. Despite this, targeted therapies have offered fresh possibilities for identifying and treating CRC, paving the way for the development of personalized medicine and extending the life expectancy and general well-being of CRC patients.

Harnessing Ferroptosis to Overcome Drug Resistance in Colorectal Cancer: Promising Therapeutic Approaches

Drug resistance remains a significant challenge in the treatment of colorectal cancer (CRC). In recent years, the emerging field of ferroptosis, a unique form of regulated cell death characterized by iron-dependent lipid peroxidation, has offered new insights and potential therapeutic strategies for overcoming drug resistance in CRC. This review examines the role of ferroptosis in CRC and its impact on drug resistance. It highlights the distinctive features and advantages of ferroptosis compared to other cell death pathways, such as apoptosis and necrosis. Furthermore, the review discusses current research advances in the field, including novel treatment approaches that target ferroptosis. These approaches involve the use of ferroptosis inducers, interventions in iron metabolism and lipid peroxidation, and combination therapies to enhance the efficacy of ferroptosis. The review also explores the potential of immunotherapy in modulating ferroptosis as a therapeutic strategy. Additionally, it evaluates the strengths and limitations of targeting ferroptosis, such as its selectivity, low side effects, and potential to overcome resistance, as well as challenges related to treatment specificity and drug development. Looking to the future, this review discusses the prospects of ferroptosis-based therapies in CRC, emphasizing the importance of further research to elucidate the interaction between ferroptosis and drug resistance. It proposes future directions for more effective treatment strategies, including the development of new therapeutic approaches, combination therapies, and integration with emerging fields such as precision medicine. In conclusion, harnessing ferroptosis represents a promising avenue for overcoming drug resistance in CRC. Continued research efforts in this field are crucial for optimizing therapeutic outcomes and providing hope for CRC patients.

A review on the role of NDRG1 in different cancers

NDRG1 is a member of the α/β hydrolase superfamily that resides in the cytoplasm and participates in the stress responses, hormone response, cell growth, and differentiation. Several studies have pointed to the importance of NDRG1 in the carcinogenesis. This gene has been found to be up-regulated in an array of cancer types such as bladder, esophageal squamous cell carcinoma, endometrial, lung and liver cancers, but being down-regulated in other types of cancers such as colorectal, gastric and ovarian cancers. The current study summarizes the evidence on the role of NDRG1 in the carcinogenic processes in different types of tissues.

Role of KLF4/NDRG1/DRP1 axis in hypoxia-induced pulmonary hypertension

N-myc downstream regulated gene 1 (NDRG1) has recently drawn increasing attention because of its involvement in angiogenesis, cell proliferation, and differentiation. We used in vitro [human pulmonary artery smooth muscle cells (hPASMCs)] and in vivo (rat) models under hypoxic conditions and found a vital role of NDRG1 in reducing apoptosis and increasing proliferation and migration by overexpressing and knocking down NDRG1. We also proved that hypoxia induced the protein expression of dynamin-related protein 1 (DRP1) and stimulated The phosphatidylinositol-3-kinase (PI3K)/ Protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathways, and these effects were reversed by NDRG1 knockdown. The relationship between NDRG1 and DRP1 and the PI3K/Akt/mTOR pathway was further evaluated by adding mdivi-1 (DRP1 inhibitor) or LY294002 (PI3K inhibitor). NDRG1 was found to regulate the proliferation, apoptosis, and migration of hypoxia-treated hPASMCs via DRP1 and PI3K/Akt/mTOR signaling pathways. We explored the upstream regulators of NDRG1 using in vivo and in vitro hypoxia models. Hypoxia was found to upregulate and downregulate KLF transcription factor 4 (KLF4) protein expression in the cytoplasm and nucleus, respectively. Further, we showed that KLF4 regulated the proliferation and migration of hypoxia-treated hPASMCs via NDRG1. These results indicated a link between KLF4, NDRG1, and DRP1 for the first time, providing new ideas for treating hypoxic pulmonary hypertension.

USP10 Regulates ZEB1 Ubiquitination and Protein Stability to Inhibit ZEB1-Mediated Colorectal Cancer Metastasis

Zinc finger E-box-binding homeobox 1 (ZEB1) is a transcription factor that can promote tumor invasion and metastasis by inducing epithelial-to-mesenchymal transition (EMT). To date, regulation of ZEB1 by RAS/RAF signaling remains unclear, and few studies have examined posttranslation modification of ZEB1, including its ubiquitination. In human colorectal cancer cell lines with RAS/RAF/MEK/ERK activation, an interaction of ZEB1 with the deubiquitinase ubiquitin-specific protease 10 (USP10) was identified whereby USP10 modifies ZEB1 ubiquitination and promotes its proteasomal degradation. Regulation of the USP10-ZEB1 interaction by MEK-ERK signaling was shown whereby constitutive activation of ERK can phosphorylate USP10 at Ser236 to impair its interaction with ZEB1 and enable ZEB1 protein stabilization. Stabilized ZEB1 was shown to promote colorectal cancer metastatic colonization in a mouse tail vein injection model. Conversely, MEK-ERK inhibition blocked USP10 phosphorylation and enhanced the USP10-ZEB1 interaction shown to suppress ZEB1-mediated tumor cell migration and metastasis. In conclusion, we demonstrate a novel function of USP10 in the regulation of ZEB1 protein stability and its ability to mediate tumor metastasis in a preclinical model.

IMPLICATIONS

The MEK-ERK-regulated interaction of USP10 with ZEB1 can promote the proteasomal degradation of ZEB1 and thereby suppress its demonstrated ability to mediate tumor metastasis.

The SLITRK4-CNPY3 axis promotes liver metastasis of gastric cancer by enhancing the endocytosis and recycling of TrkB in tumour cells

PURPOSE

Gastric cancer (GC) is a malignant tumour with high mortality, and liver metastasis is one of the main causes of poor prognosis. SLIT- and NTRK-like family member 4 (SLITRK4) plays an important role in the nervous system, such as synapse formation. Our study aimed to explore the functional role of SLITRK4 in GC and liver metastasis.

METHODS

The mRNA level of SLITRK4 was evaluated using publicly available transcriptome GEO datasets and Renji cohort. The protein level of SLITRK4 in the tissue microarray of GC was observed using immunohistochemistry. Cell Counting Kit-8, colony formation, transwell migration assays in vitro and mouse model of liver metastasis in vivo was performed to investigate the functional roles of SLITRK4 in GC. Bioinformatics predictions and Co-IP experiments were applied to screen and identify SLITRK4-binding proteins. Western blot was performed to detect Tyrosine Kinase receptor B (TrkB)-related signaling molecules.

RESULTS

By comparing primary and liver metastases from GC, SLITRK4 was found to be upregulated in tissues of GC with liver metastasis and to be closely related to poor clinical prognosis. SLITRK4 knockdown significantly abrogated the growth, invasion, and metastasis of GC in vitro and in vivo. Further study revealed that SLITRK4 could interact with Canopy FGF Signalling Regulator 3 (CNPY3), thus enhancing TrkB- related signaling by promoting the endocytosis and recycling of the TrkB receptor.

CONCLUSION

In conclusion, the CNPY3-SLITRK4 axis contributes to liver metastasis of GC according to the TrkB-related signaling pathway. which may be a therapeutic target for the treatment of GC with liver metastasis.

MicroRNA 483-3p overexpression unleashes invasive growth of metastatic colorectal cancer via NDRG1 downregulation and ensuing activation of the ERBB3/AKT axis

In colorectal cancer, the mechanisms underlying tumor aggressiveness require further elucidation. Taking advantage of a large panel of human metastatic colorectal cancer xenografts and matched stem-like cell cultures (m-colospheres), here we show that the overexpression of microRNA 483-3p (miRNA-483-3p; also known as MIR-483-3p), encoded by a frequently amplified gene locus, confers an aggressive phenotype. In m-colospheres, endogenous or ectopic miRNA-483-3p overexpression increased proliferative response, invasiveness, stem cell frequency, and resistance to differentiation. Transcriptomic analyses and functional validation found that miRNA-483-3p directly targets NDRG1, known as a metastasis suppressor involved in EGFR family downregulation. Mechanistically, miRNA-483-3p overexpression induced the signaling pathway triggered by ERBB3, including AKT and GSK3β, and led to the activation of transcription factors regulating epithelial-mesenchymal transition (EMT). Consistently, treatment with selective anti-ERBB3 antibodies counteracted the invasive growth of miRNA-483-3p-overexpressing m-colospheres. In human colorectal tumors, miRNA-483-3p expression inversely correlated with NDRG1 and directly correlated with EMT transcription factor expression and poor prognosis. These results unveil a previously unrecognized link between miRNA-483-3p, NDRG1, and ERBB3-AKT signaling that can directly support colorectal cancer invasion and is amenable to therapeutic targeting.

Liver X receptor agonists exert antitumor effects against hepatocellular carcinoma via inducing REPS2 expression

Recent studies show that liver X receptor (LXR) agonists exert significant antitumor effects in a variety of tumor cell lines including hepatocellular carcinoma (HCC). But the molecular mechanisms underlying LXR antitumor activity are not fully understood. In this study we investigated the effect of LXR agonist T0901317 (T317) on HCC development and its relationship with RalA binding protein 1 (RALBP1)-associated EPS domain containing 2 (REPS2)/epidermal growth factor receptor (EGFR) signaling axis. We showed that T317 (0.1-0.5 μM) dose-dependently increased REPS2 expression in normal hepatocytes (BNLCL.2 and LO2) and HCC cells (HepG2 and Huh-7). Using promoter activity assay and chromatin immunoprecipitation (CHIP) assay we demonstrated that T317 enhanced REPS2 expression at the transcriptional level via promoting the binding of LXR protein to the LXR-response element (LXRE) in the REPS2 promoter region. We showed that the inhibitory effect of T317 on the proliferation and migration of HCC cells was closely related to REPS2. Moreover, we revealed that T317 (400 nM) increased expression of REPS2 in HepG2 cells, thus inhibiting epidermal growth factor (EGF)-mediated endocytosis of EGFR as well as the downstream activation of AKT/NF-κB, p38MAPK, and ERK1/2 signaling pathways. Clinical data analysis revealed that REPS2 expression levels were inversely correlated with the development of HCC and reduced REPS2 expression associated with poor prognosis, suggesting that REPS2 might be involved in the development of HCC. In conclusion, this study provides new insights into the potential mechanisms of LXR agonist-inhibited HCC.

N-myc downstream regulated gene 1 inhibition of tumor progression in Caco2 cells

BACKGROUND

Invasion and migration are the irreversible stages of colorectal cancer (CRC). The key is to find a sensitive, reliable molecular marker that can predict the migration of CRC at an early stage. N-myc downstream regulated gene 1 (NDRG1) is a multifunctional gene that has been tentatively reported to have a strong relationship with tumor invasion and migration, however the current molecular role of NDRG1 in CRC remains unknown.

AIM

To explore the role of NDRG1 in the development of CRC.

METHODS

NDRG1 stably over-expressed Caco2 cell line was established by lentiviral infection and NDRG1 knock-out Caco2 cell line was established by CRISPR/Cas9. Furthermore, the mRNA and protein levels of NDRG1 in Caco2 cells after NDRG1 over-expression and knockout were detected by real-time polymerase chain reaction and western blot. The cell proliferation rate was measured by the cell counting kit-8 method; cell cycle and apoptosis were detected by flow cytometry; invasion and migration ability were detected by the 24-transwell method.

RESULTS

NDRG1 over-expression inhibited Caco2 proliferation and the cell cycle could be arrested at the G1/S phase when NDRG1 was over-expressed, while the number of cells in the G2 phase was significantly increased when NDRG1 was knocked out. This suggests that NDRG1 inhibited the proliferation of Caco2 cells by arresting the cell cycle in the G1/S phase. Our data also demonstrated that NDRG1 promotes early cell apoptosis. Invasion and migration of cells were extensively inhibited when NDRG1 was over-expressed.

CONCLUSION

NDRG1 inhibits tumor progression in Caco2 cells which may represent a potential novel therapeutic strategy for the treatment of CRC.

Proteomic and Phosphoproteomic Analyses Reveal the Oncogenic Role of PTK7-NDRG1 Axis in Non-small-cell Lung Cancer Cell Resistance to AZD9291

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are the most important chemotherapeutics for non-small-cell lung cancer (NSCLC) therapy. The resistance to EGFR-TKIs is one of the biggest obstacles to NSCLC outcome. In this study, taking advantage of phospho- and proximal proteomic techniques, we analyzed the network rearrangement in cell lines responding to AZD9291 treatment and found that cell-cell adhesion was dramatically enhanced in AZD9291-resistant cells. Further analysis revealed that protein tyrosine kinase 7 (PTK7) expression was significantly elevated. Knockdown or overexpression assays showed that PTK7 played a critical role in improving cell adhesion, which enhanced drug resistance. Because PTK7 is a membrane-localized pseudokinase, the proximal labeling probe BirA* was fused to reveal PTK7-interacting proteins. We found that PTK7 interacted with and stabilized NDRG1, which is located predominantly adjacent to adherens junctions. Downregulation of PTK7 or NDRG1 eliminated the resistance of H1975-resistant (H1975-R) and PC9-resistant (PC9-R) cells to AZD9291, suggesting that the PTK7-NDRG1 axis might be a potential target to eliminate the EGFR-TKI resistance during NSCLC therapy.

Upregulated SPAG6 promotes acute myeloid leukemia progression through MYO1D that regulates the EGFR family expression

Chromosomal aberrations and gene mutations have been considered to be the major reasons for high recurrence rates and poor survival among acute myeloid leukemia (AML) patients. However, the underlying molecular mechanism of AML gene mutation remains largely unclear. Here, we show that SPAG6 (sperm-associated antigen 6), one of the most markedly increased SPAG genes in AML, significantly contributed to the proliferation and migration of leukemic cells. SPAG6 was highly expressed in AML, and its upregulation was negatively correlated with the prognosis of the disease. In vitro, SPAG6 promoted the proliferation and migration of leukemia cells and promoted cell cycle progression from the G1 phase to the S phase. In vivo, low expression of SPAG6 reduced the proliferation and infiltration of leukemia cells and prolonged the survival of xenograft tumor mice. Furthermore, immunoprecipitation and mass spectrometry analysis showed that SPAG6 interacts with MYO1D (myosin 1D). Specifically, overexpression of SPAG6 promoted the translocation of MYO1D into the cell membrane, thus upgrading the expression level of the EGFR family and thereby promoting the progression of AML. Overall, our study found that SPAG6 combined with MYO1D and translocated MYO1D from the cytosol to the cytomembrane, which induced the PI3K (phosphoinositide 3-kinase)/AKT (protein kinase B) signaling and ERK (extracellular signal-regulated kinase) signaling pathway to regulate the growth and prognosis of AML. SPAG6 may become a new target gene for the treatment of AML.

Novel iron chelator SK4 demonstrates cytotoxicity in a range of tumour derived cell lines

Iron is an essential micronutrient due to its involvement in many cellular processes including DNA replication and OXPHOS. Tumors overexpress iron metabolism linked proteins which allow for iron accumulation driving high levels of proliferation. Our group has designed novel iron chelator SK4 which targets cancer’s “iron addiction.” SK4 comprises of two key moieties: an iron chelation moiety responsible for cytotoxicity and an amino acid moiety which allows entry through amino acid transporter LAT1. We selected LAT1 as a route of entry as it is commonly overexpressed in malignant tumors. SK4 has previously demonstrated promising results in an in vitro model for melanoma. We hypothesized SK4 would be effective against a range of tumor types. We have screened a panel of tumor-derived cell lines from different origins including breast, prostate, ovarian and cervical cancer for SK4 sensitivity and we have found a range of differential sensitivities varying from 111.3 to >500 μM. We validated the iron chelation moiety as responsible for inducing cytotoxicity through control compounds; each lacking a key moiety. Following the screen, we conducted a series of assays to elucidate the mechanism of action behind SK4 cytotoxicity. SK4 was shown to induce apoptosis in triple negative breast cancer cell line MDA MB 231 but not ovarian cancer cell line SKOV3 suggesting SK4 may induce different modes of cell death in each cell line. As MDA MB 231 cells harbor a mutation in p53, we conclude SK4 is capable of inducing apoptosis in a p53-independent manner. SK4 upregulated NDRG1 expression in MDA MB 231 and SKOV3 cells. Interestingly, knockdown of NDRG1 antagonized SK4 in MDA MB 231 cells but not SKOV3 cells suggesting SK4’s mechanism of action may be mediated through NDRG1 in MDA MB 231 cells. In conclusion, we have shown tagging iron chelators with an amino acid moiety to allow entry through the LAT1 transporter represents a double pronged approach to cancer therapy, targeting “iron addiction” and amino acid metabolism dysregulation.

Dimeric-(-)-epigallocatechin-3-gallate inhibits the proliferation of lung cancer cells by inhibiting the EGFR signaling pathway

Non-small cell lung cancer (NSCLC) is one of the most general malignant tumors. The overexpression of epidermal growth factor receptor (EGFR) is a common marker in NSCLC, and it plays an important role in the proliferation, invasion, and metastasis of cancer cells. At present, drugs developed with EGFR as a target suffer from drug resistance, so it is necessary to study new compounds for the treatment of NSCLC. The active substance in green tea is EGCG, which has anti-cancer effects. In this study, we synthesized dimeric-(-)-epigallocatechin-3-gallate (prodelphinidin B-4-3,3‴-di-O-gallate, PBOG), and explored the effect of PBOG on lung cancer cells. PBOG can inhibit the proliferation and migration of NCI-H1975 cells, promote cell apoptosis, and inhibit cell cycle progression. In addition, PBOG can bind to the EGFR ectodomain protein and change the secondary structure of the protein. At the same time, PBOG decreases the expression of EGFR and downstream protein phosphorylation. Animal experiments confirmed that PBOG can inhibit tumor growth by inhibiting EGFR phosphorylation. Collectively, our study results show that PBOG may induce a decrease in intracellular phosphorylated EGFR expression by binding to the EGFR ectodomain protein, thereby inducing apoptosis and inhibiting cell cycle progression, thus providing a new strategy to treat lung cancer.

Noninvasive Evaluation of EGFR Expression of Digestive Tumors Using 99mTc-MAG3-Cet-F(ab ′ )2-Based SPECT/CT Imaging

Purpose. This study is aimed at investigating the feasibility of cetuximab (Cet) F(ab ${}^{\prime }$ )2 fragment- (Cet-F(ab ${}^{\prime }$ )2-) based single photon emission tomography/computed tomography (SPECT/CT) for assessing the epidermal growth factor receptor (EGFR) expression in digestive tumor mouse models. Methods. Cet-F(ab ${}^{\prime }$ )2 was synthesized using immunoglobulin G-degrading enzyme of Streptococcus pyogenes (IdeS) protease and purified with protein A beads. The product and its in vitro stability in normal saline and 1% bovine serum albumin were analyzed with sodium dodecyl sulfate–polyacrylamide gel electrophoresis. The EGFR expression in the human colon tumor cell line HT29 and the human stomach tumor cell line MGC803 were verified using western blotting and immunocytochemistry. Cet-F(ab ${}^{\prime }$ )2 was conjugated with 5(6)-carboxytetramethylrhodamine succinimidyl ester to demonstrate its binding ability to the MGC803 and HT29 cells. Cet-F(ab ${}^{\prime }$ )2 was conjugated with NHS-MAG3 for 99mTc radiolabeling. The best imaging time was determined using a biodistribution assay at 1, 4, 16, and 24 h after injection of the 99mTc-MAG3-Cet-F(ab ${}^{\prime }$ )2 tracer. Furthermore, 99mTc-MAG3-Cet-F(ab ${}^{\prime }$ )2 SPECT/CT was performed on MGC803 and HT29 tumor-bearing nude mice. Results. HT29 cells had low EGFR expression while MGC803 cell exhibited the high EGFR expression. Cet-F(ab ${}^{\prime }$ )2 and intact cetuximab showed similar high binding ability to MGC803 cells but not to HT29 cells. Cet-F(ab ${}^{\prime }$ )2 and 99mTc-MAG3-Cet-F(ab ${}^{\prime }$ )2 showed excellent in vitro stability. The biodistribution assay showed that the target to nontarget ratio was the highest at 16 h ( $17.29\pm 5.72$ , $n=4$ ) after tracer injection. The 99mTc-MAG3-Cet-F(ab ${}^{\prime }$ )2-based SPECT/CT imaging revealed rapid and sustained tracer uptake in MGC803 tumors rather than in HT29 tumors with high image contrast, which was consistent with the results in vitro. Conclusion. SPECT/CT imaging using 99mTc-MAG3-Cet-F(ab ${}^{\prime }$ )2 enables the evaluation of the EGFR expression in murine EGFR-positive tumors, indicating the potential utility for noninvasive evaluation of the EGFR expression in tumors.

Colorectal Cancer Diagnosis: The Obstacles We Face in Determining a Non-Invasive Test and Current Advances in Biomarker Detection

Simple Summary

Colorectal cancer (CRC) is one of the most common cancers in the western world. CRC originates from precursor adenomatous polyps, which may over time develop into cancer. Endoscopic evaluation remains the gold-standard investigation for the disease. In the absence of molecular tools for early detection, the removal of neoplastic adenomas via polypectomy remains an important measure to prevent dysplastic adenomas from evolving into invasive carcinoma. Colonoscopy is an intrusive procedure that provides an uncomfortable experience for patients. Kits for testing for the presence of blood hemoglobin in the stool are now widely used, and DNA methylation-based detection kits have been approved in the USA for testing the stool and plasma, but few other molecular biomarkers have found their way into medical practice. This review summarizes current trends in the detection and screening of CRC and provides a definitive review of emerging molecular biomarkers for CRC.

Abstract

Globally, colorectal cancer (CRC) is the third most common cancer, with 1.4 million new cases and over 700,000 deaths per annum. Despite being one of the most common cancers, few molecular approaches to detect CRC exist. Carcinoembryonic antigen (CEA) is a known serum biomarker that is used in CRC for monitoring disease recurrence or response to treatment. However, it can also be raised in multiple benign conditions, thus having no value in early detection or screening for CRC. Molecular biomarkers play an ever-increasing role in the diagnosis, prognosis, and outcome prediction of disease, however, only a limited number of biomarkers are available and none are suitable for early detection and screening of CRC. A PCR-based Epi proColon^® blood plasma test for the detection of methylated SEPT9 has been approved by the USFDA for CRC screening in the USA, alongside a stool test for methylated DNA from CRC cells. However, these are reserved for patients who decline traditional screening methods. There remains an urgent need for the development of non-invasive molecular biomarkers that are highly specific and sensitive to CRC and that can be used routinely for early detection and screening. A molecular approach to the discovery of CRC biomarkers focuses on the analysis of the transcriptome of cancer cells to identify differentially expressed genes and proteins. A systematic search of the literature yielded over 100 differentially expressed CRC molecular markers, of which the vast majority are overexpressed in CRC. In terms of function, they largely belong to biological pathways involved in cell division, regulation of gene expression, or cell proliferation, to name a few. This review evaluates the current methods used for CRC screening, current availability of biomarkers, and new advances within the field of biomarker detection for screening and early diagnosis of CRC.

Cyclin D1 Serves as a Poor Prognostic Biomarker in Stage I Gastric Cancer

TNM stage still serves as the best prognostic marker in gastric cancer (GC). The next step is to find prognostic biomarkers that detect subgroups with different prognoses in the same TNM stage. In this study, the expression levels of epidermal growth factor receptor (EGFR) and cyclin D1 were assessed in 96 tissue samples, including non-tumorous tissue, adenoma, and carcinoma. Then, the prognostic impact of EGFR and cyclin D1 was retrospectively investigated in 316 patients who underwent R0 resection for GC. EGFR positivity increased as gastric tissue became malignant, and cyclin D1 positivity was increased in all the tumorous tissues. However, there was no survival difference caused by the EGFR positivity, while the cyclin D1-postive group had worse overall survival (OS) than the cyclin D1-negative group in stage I GC (10-year survival rate (10-YSR): 62.8% vs. 86.5%, p = 0.010). In subgroup analyses for the propensity score-matched (PSM) cohort, there were also significant differences in the OS according to the cyclin D1 positivity in stage I GC but not in stage II and III GC. Upon multivariate analysis, cyclin D1 positivity was an independent prognostic factor in stage I GC. In conclusion, cyclin D1 may be a useful biomarker for predicting prognosis in stage I GC.

Claudin-2 promotes colorectal cancer growth and metastasis by suppressing NDRG1 transcription

Colorectal cancer (CRC) is one of the most common malignant tumours, with multiple driving factors and biological transitions involved in its development. Claudin-2 (CLDN2), a well-defined component of cellular tight junction, has been indicated to associate with CRC progression. However, the function of CLDN2 and the underlying mechanism whereby the downstream signalling transduction is regulated in CRC remains largely unclear. In this study, we demonstrated that CLDN2 is upregulated in CRC samples and associated with poor survival. And CLDN2 depletion significantly promotes N-myc downstream-regulated gene 1 (NDRG1) transcription, leading to termination of the CRC growth and metastasis in vitro and in vivo. Mechanistically, this process promotes CLDN2/ZO1/ZONAB complex dissociation and ZONAB shuttle into nucleus to enrich in the promoter of NDRG1. Thus, this study reveals a novel CLDN2/ZO1/ZONAB-NDRG1 axis in CRC by regulating the expression of EMT-related genes and CDKIs, suggesting CLDN2 may serve as a promising target for CRC treatment.