Ligand-Independent Epidermal Growth Factor Receptor Overexpression Correlates with Poor Prognosis in Colorectal Cancer

Systematic literature review and meta-analysis of HER2 amplification, overexpression, and positivity in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer death globally. Recent clinical trials suggest an emerging role for HER2 as a potential clinically relevant biomarker in CRC. Testing for HER2 in CRC is not standard practice; consequently, the prevalence of HER2 positivity (HER2+) in patients with CRC remains uncertain.

METHODS

A systematic literature review and meta-analysis were conducted to generate estimates of proportions of patients with CRC with HER2 overexpression or HER2 amplification and HER2+ (either overexpression or amplification), overall and in patients with rat sarcoma virus (RAS) wild-type cancer. HER2+ was defined as 1) immunohistochemistry with a score of 3+, 2) immunohistochemistry with a score of 2+ and in situ hybridization+, or 3) next-generation sequencing positive.

RESULTS

Of 224 studies identified with information on HER2 in CRC, 52 studies used a US Food and Drug Administration-approved assay and were selected for further analysis. Estimated HER2+ rate was 4.1% (95% confidence interval [CI] = 3.4% to 5.0%) overall (n = 17 589). HER2+ rates were statistically higher in RAS wild-type (6.1%, 95% CI = 5.4% to 6.9%) vs RAS mutant CRC (1.1%, 95% CI = 0.3% to 4.4%; P < .0001). Despite limited clinical information, we confirmed enrichment of HER2+ CRC in patients with microsatellite stable and left-sided CRC.

CONCLUSION

This meta-analysis provides an estimate of HER2+ CRC and confirms enrichment of HER2 in microsatellite stable, left-sided, RAS wild-type CRC tumors. Our work is important given the recently described clinical efficacy of HER2-targeted therapies in HER2+ CRC and informs strategies for incorporation of HER2 testing into standard of care.

Molecular characterization of colorectal mucinous adenocarcinoma and adenocarcinoma, not otherwise specified, identified by multiomic data analysis

Adenocarcinoma not otherwise specified (AC) and mucinous adenocarcinoma (MC) have different biological behaviors and clinical features. We utilized our previous proteomic data and public transcriptome, single-cell transcriptome, and spatial transcriptome databases to profile the molecular atlas of the tumor microenvironments of MC, AC, and normal colon tissues. By exploring the general and specific molecular features of AC and MC, we found that AC was immune-active but exposed to a hypoxic microenvironment. MC cells could protect against DNA damage, and the microenvironment was unfavorable to leukocyte transendothelial migration. We identified several potential molecular and cellular targets of AC and MC for future research. We also highlighted that the major difference between AC and MC was not the variety of cell types and functions but possibly cell interactions. Stromal and epithelial cell interactions play important roles in both MC and AC, but different regulatory pathways were involved.

Growth Factors, PI3K/AKT/mTOR and MAPK Signaling Pathways in Colorectal Cancer Pathogenesis: Where Are We Now?

Colorectal cancer (CRC) is a predominant malignancy worldwide, being the fourth most common cause of mortality and morbidity. The CRC incidence in adolescents, young adults, and adult populations is increasing every year. In the pathogenesis of CRC, various factors are involved including diet, sedentary life, smoking, excessive alcohol consumption, obesity, gut microbiota, diabetes, and genetic mutations. The CRC tumor microenvironment (TME) involves the complex cooperation between tumoral cells with stroma, immune, and endothelial cells. Cytokines and several growth factors (GFs) will sustain CRC cell proliferation, survival, motility, and invasion. Epidermal growth factor receptor (EGFR), Insulin-like growth factor -1 receptor (IGF-1R), and Vascular Endothelial Growth Factor -A (VEGF-A) are overexpressed in various human cancers including CRC. The phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) and all the three major subfamilies of the mitogen-activated protein kinase (MAPK) signaling pathways may be activated by GFs and will further play key roles in CRC development. The main aim of this review is to present the CRC incidence, risk factors, pathogenesis, and the impact of GFs during its development. Moreover, the article describes the relationship between EGF, IGF, VEGF, GFs inhibitors, PI3K/AKT/mTOR-MAPK signaling pathways, and CRC.

Research on Anti-Tumor Nano-Particle with New Type 5-Fluorouracil on the Peritoneal Metastasis of Breast Cancer

The 5-fluorouracil (5-FU) was a classical chemotherapy drug. The administrational carrier of nano-particle provides enhancement effect prior to target and reduce side effect. But the specific function of nano-particle on the peritoneal metastasis of breast cancer was poorly understood. Our study was designed to discover the biological function of anti-tumor nano-particle with new type 5-FU on breast cancer. The nano-particle of 5-fluorouracil (5-FU-NPs) was prepared by multiple emulsion method. The distribution of particle size was analyzed by electron microscope. The proliferation and apoptosis of cell in breast cancer was interfered by 5-FU solution (control group) or 5-FU-NPs. Cell cycle was assessed by flow cytometry and proliferation was detected by MTT and cell clone technology. The rat was injected with 5-FU solution (control group) or 5-FU-NPs intraperitoneally followed by analysis of tumor volume and size. The average tumor diameter was 200±10.84 nm. The encapsulation rate and loading rate was 81.6±5.7% and 7.29±0.14% respectively. The apoptosis of MCF-7 cell treated by 5-FU-NPs was increased significantly with abundant rounded and floating apoptotic cellular morphology as well as reduced quantity of surviving cells. The number of bacterial colony induced by 5-FU-NPs, which could interdict cell cycle. The 5-FU-NPs could restrain tumor cell growth in peritoneal metastasis of breast cancer. The new-type nano-particle of 5-FU loaded with PEG-PLGA could retard breast cancer cell proliferation and peritoneal metastasis of breast cancer in rats.

Epidermal Growth Factor Receptor: Key to Selective Intracellular Delivery

Epidermal growth factor receptor (EGFR) is an integral surface protein mediating cellular response to a number of growth factors. Its overexpression and increased activation due to mutations is one of the most common traits of many types of cancer. Development and clinical use of the agents, which block EGFR activation, became a prime example of the personalized targeted medicine. However, despite the obvious success in this area, cancer cure remains unattainable in most cases. Because of that, as well as the result of the search for possible ways to overcome the difficulties of treatment, a huge number of new treatment methods relying on the use of EGFR overexpression and its changes to destroy cancer cells. Modern data on the structure, functioning, and intracellular transport of EGFR, its natural ligands, as well as signaling cascades triggered by the EGFR activation, peculiarities of the EGFR expression and activation in oncological disorders, as well as applied therapeutic approaches aimed at blocking EGFR signaling pathway are summarized and analyzed in this review. Approaches to the targeted delivery of various chemotherapeutic agents, radionuclides, immunotoxins, photosensitizers, as well as the prospects for gene therapy aimed at cancer cells with EGFR overexpression are reviewed in detail. It should be noted that increasing attention is being paid nowadays to the development of multifunctional systems, either carrying several different active agents, or possessing several environment-dependent transport functions. Potentials of the systems based on receptor-mediated endocytosis of EGFR and their possible advantages and limitations are discussed.

Enhanced antitumor efficacy in colon cancer using EGF functionalized PLGA nanoparticles loaded with 5-Fluorouracil and perfluorocarbon

Background

Tumor recurrence and metastasis occur at a high rate in patients with colon cancer. Identification of effective strategies for the treatment of colon cancer is critical. Recently, poly (lactic-co-glycolic acid) (PLGA) has been shown to have potential as a broad therapeutic drug delivery system. We designed a dual-loaded nanoparticle drug delivery system to overcome the limitations of chemotherapeutic drugs used to treat colon cancer.

Methods

We developed epidermal growth factor (EGF) functionalized PLGA nanoparticles (NPs) co-loaded with 5-fluorouracil (5Fu) and perfluorocarbon (PFC) (EGF-PLGA@5Fu/PFC) for targeted treatment of colon cancer. CCK-8 assay, Hoechst33342 staining and flow cytometry were performed to investigate the functions of EGF-PLGA@5Fu/PFC NPs in SW620 cells. Beside, animal experiment, histological analysis and immunofluorescence staining were adopted to further confirm the role of EGF-PLGA@5Fu/PFC NPs in vivo.

Results

The findings showed that EGF-PLGA@5Fu /PFC NPs had an average size 200 nm and a 5Fu-loading efficiency of 7.29%. Furthermore, in vitro release was pH-sensitive. Targeted EGF-PLGA@5Fu/PFC NPs exhibited higher cellular uptake than non-targeted NPs into colon cancer cells. In addition, EGF-PLGA@5Fu/PFC NPs suppressed cell viability and induced apoptosis in SW620 cells to a greater extent than non-targeted NPs. In tumor xenografted mice, EGF-PLGA@5Fu/PFC NPs suppressed tumor growth more effectively than 5Fu, PLGA@5Fu or PLGA@5Fu/PFC NPs. Histopathological analysis further demonstrated that EGF-targeted NPs inhibited tumor growth to a greater extent than non-targeted or non-NP treatments. The improved therapeutic outcomes observed in this study were due to relief of tumor hypoxia by transport of oxygen by PFC to the tumors.

Conclusion

We constructed a biocompatible nanodrug delivery system based on functionalized nanoparticles that provided a novel strategy for selective delivery of chemotherapy drugs to tumors.

Combined Therapeutic Effects of 131I-Labeled and 5Fu-Loaded Multifunctional Nanoparticles in Colorectal Cancer

Background

Owing to its combined effects, the co-delivery of different therapeutics is a promising option for the treatment of cancer. In the present study, tumor-targeting poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) nanoparticles were developed for the transportation of two molecules, namely chemotherapeutic drug 5-fluorouracil (5Fu) and radionuclide iodine-131 (¹³¹I), in a single platform.

Methods

The obtained nanoparticles (Cetuximab [Cet]-PEG-PLA-5Fu-¹³¹I) were spherical (diameter approximately 110 nm) and pH-sensitive. The targeting effect of nanoparticles via Cet was confirmed in colorectal cancer cells using a fluorescent assay. The combined effects of Cet-PEG-PLA-5Fu-¹³¹I on cell viability and apoptosis were evaluated in colorectal cancer cells by Cell Counting Kit-8 and flow cytometry assays.

Results

Blank nanoparticles (Cet-PEG-PLA) showed good biocompatibility, and Cet-PEG-PLA-5Fu-¹³¹I nanoparticles were the most effective in terms of inhibition of cell viability and induction of apoptosis compared with monotherapy using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-¹³¹I. In the xenograft mouse model, compared with using Cet-PEG-PLA-5Fu or Cet-PEG-PLA-¹³¹I alone, Cet-PEG-PLA-5Fu-¹³¹I nanoparticles exhibited prolonged circulation in the blood and accumulation in the tumor, thus resulting in enhanced antitumor efficacy. Additionally, combined radio-chemotherapy with Cet-PEG-PLA-5Fu-¹³¹I nanoparticles was associated with smaller tumor sizes than monotherapy, revealing the superior antitumor effects of Cet-PEG-PLA-5Fu-¹³¹I nanoparticles. These effects were further evidenced by histological and immunohistochemical analyses.

Conclusion

The multifunctional Cet-PEG-PLA-5Fu-¹³¹I nanoparticles are promising candidates for the co-delivery of 5Fu-mediated chemotherapy and ¹³¹I-mediated radiotherapy.

SOX2 Promotes Brain Metastasis of Breast Cancer by Upregulating the Expression of FSCN1 and HBEGF

The prognosis of breast cancer brain metastasis (BCBM) is extremely poor due to its resistance to conventional therapy. Elucidation of the molecular mechanisms of BCBM could contribute to the development of new therapeutic targets. In this study, we isolated RNA samples from primary breast cancer or BCBM, and then performed mRNA profiling. We determined that SOX2 is associated with the occurrence of BCBM and could be a predictor of BCBM. High levels of SOX2 were significantly associated with decreasing BCBM-free survival in patients. Overexpression of SOX2 in breast cancer cells enhanced cancer cell adhesion to brain microvascular endothelial cells, transendothelial migration, and in vitro blood-brain barrier (BBB) migration, whereas silencing SOX2 inhibited these events. SOX2 can increase cancer cell migration and BBB permeability by upregulating FSCN1 and HBEGF, thereby promoting BBB migration of breast cancer cells. Moreover, high levels of FSCN1 and HBEGF were significantly associated with reducing BCBM-free survival in breast cancer patients. Further study indicated that SOX2 mediates the expression of HBEGF and FSCN1 by activating AKT and β-catenin signaling pathways. Additionally, in vivo experiments showed that SOX2 promotes the development of BCBM. This study demonstrated that SOX2 promotes BCBM by upregulating the expression of FSCN1 and HBEGF.

HER4 promotes the progression of colorectal cancer by promoting epithelial‑mesenchymal transition

Colorectal cancer (CRC) remains one of the most common cancer types worldwide. A few previous studies have examined whether HER4 may promote the progression of CRC. The present study examined the associations among the expression levels of members of the HER family, and investigated the potential mechanism underlying the function of HER4 in CRC cells. Immunohistochemistry analysis was conducted to detect the expression levels of HER family members in patients with CRC. HER4 expression was knocked down using short hairpin RNA in HCT116 cells, and confirmed by quantitative PCR and western blotting. The proliferation and adhesion of CRC cells were analyzed by CCK-8 assays and adhesive assays, respectively. Flow cytometry was used to measure cell apoptosis. Western blotting and immunofluorescence staining in CRC cells were performed to identify proteins related to epithelial-mesenchymal transition. The proportion of patients with CRC presenting positive expression of the HER family members epidermal growth factor receptor (EGFR), HER2, HER3 and HER4 were 72.1, 45.2, 43.8 and 34.2%, respectively. No relationship was found between HER4 and EGFR, HER2 or HER3 expression. Higher expression of HER4 was positively associated with lymph node metastasis (P=0.039). In the present study, HER4 expression was found to be associated with an unfavorable clinical outcome in patients with CRC (P_logrank=0.020). Cell proliferation was inhibited, and apoptosis was increased following HER4 knockdown. Furthermore, HER4 knockdown increased the expression of E-cadherin and decreased the expressions of N-cadherin and vimentin (P<0.05). HER4 expression was found to be unrelated to other HER family members. In the present study, positive expression of HER4 promoted the progression of CRC through epithelial-mesenchymal transition.

Co-expression and prognostic significance of putative CSC markers CD44, CD133, wild-type EGFR and EGFRvIII in metastatic colorectal cancer

The presence of colorectal cancer stem cells (CSCs) have been associated with tumour initiation and resistance to therapy. This study investigated the co-expression and prognostic significance of the CSCs biomarkers CD44 and CD133 with wild-type EGFR (wtEGFR) and EGFRvIII in colorectal cancer (CRC). The expression of these biomarkers were determined in tumours from 70 patients with metastatic CRC by immunohistochemistry, and in a panel of human CRC cell lines, and their variants with acquired-resistance to EGFR inhibitors, by flow cytometry. The expression of CD44, CD133, wtEGFR and EGFRvIII were present in 17%, 23%, 26% and 13% of cases and the co-expression of CD44/CD133 with wtEGFR and EGFRvIII were present in 9% and 3% of the cases respectively. Only co-expression of CSCs/EGFRvIII (P = 0.037), and amphiregulin (P = 0.017) were associated with worse overall survival. Interestingly, disease-free survival was improved in BTC expressing patients (P = 0.025). In vitro CD133 expression and its co-expression with CD44 were associated with primary-resistance to irinotecan and acquired-resistance to anti-EGFR inhibitors respectively. Our results suggest co-expression of CSCs and EGFRvIII could be potential biomarkers of worse overall survival and resistance to therapy in patients with mCRC and warrants further validation in a larger cohort.