MUC1 Expression in Pulmonary Metastatic Tumors: A Comparison of Primary Lung Cancer

The effect of Moringa oleifera leaf extracts against urethane-induced lung cancer in rat model

Lung cancer is one of the most common malignancies in the world, and chemotherapy can have unfavorable side effects. The aim of the present study is to evaluate the therapeutic anticancer role of Moringa oleifera leaf extracts (MLE) in urethane-induced lung cancer in adult male albino rats as compared to standard chemotherapy. Rats were categorized into four groups (10 rats/group), including negative control rats, urethane lung cancer model rats, MLE-treated lung cancer rats, and cisplatin-treated rats. Estimation of lung index, some biochemical markers of oxidative stress, quantitative real-time polymerase chain reaction (qRT-PCR), and histopathology and transmission electron microscopy were performed. The lung index was significantly increased about one-fold in urethane lung cancer model rats, but it decreased after MLE treatment. Also, MLE was able to improve the induced changes in glutathione, superoxide dismutase, and malondialdehyde concentration to be 3.8 ± 0.4 mg/g, 900.6 ± 58 U/g, and 172 ± 24 nmol/g, respectively. Additionally, after MLE treatment, the expression of EGFR-mRNA increased by about 50%. Our light and electron microscopic examination revealed that urethane group showed abnormally distributed excessive collagen fibers and the development of papillary adenocarcinoma from hyperplastic Clara cells in the lumen of terminal bronchiole with bronchiolar wall thickening, alveolar collapse, and inflammation. MLE group has moderate amount of collagen fiber and absence of tumor mass and provided more or less restoration of normal lung histology. Moreover, MLE was able to ameliorate the induced changes in mucin and PCNA positive cells in the lung by 10.8 ± 2.3%. Collectively, the current study showed that MLE could be used as anticancer agents alleviating changes associated with lung cancer in a urethane-induced lung cancer bearing rats thereby representing alternative options to toxic chemotherapy.

MUC1-C influences cell survival in lung adenocarcinoma Calu-3 cells after SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces coronavirus disease 2019 (COVID-19) and may increase the risk of adverse outcomes in lung cancer patients. In this study, we investigated the expression and function of mucin 1 (MUC1) after SARS-CoV-2 infection in the lung epithelial cancer cell line Calu-3. MUC1 is a major constituent of the mucus layer in the respiratory tract and contributes to pathogen defense. SARS-CoV-2 infection induced MUC1 C-terminal subunit (MUC1-C) expression in a STAT3 activation-dependent manner. Inhibition of MUC1-C signaling increased apoptosis-related protein levels and reduced proliferation-related protein levels; however, SARS-CoV-2 replication was not affected. Together, these results suggest that increased MUC1-C expression in response to SARS-CoV-2 infection may trigger the growth of lung cancer cells, and COVID-19 may be a risk factor for lung cancer patients.

The Effect of GLUT1 on Survival Rate and the Immune Cell Infiltration of Lung Adenocarcinoma and Squamous Cell Carcinoma: A Meta and Bioinformatics Analysis

BACKGROUND

Lung adenocarcinoma (LUAD) and squamous cell carcinoma (LUSC) are two major subtypes of non-small cell lung cancer (NSCLC). Studies have shown that abnormal expression of glucose transport type 1 (GLUT1) in NSCLC patients has been associated with progression, aggressiveness, and poor clinical outcome. However, the clinical effect of GLUT1 expression on LUAD and LUSC is unclear.

OBJECTIVE

This study aims to learn more about the character of GLUT1 in LUAD and LUSC.

METHODS

A meta-analysis was performed to evaluate the GLUT1 protein level, and bioinformatics analysis was used to detect the GLUT1 mRNA expression level, survival differences, and the infiltration abundance of immune cells in samples from TCGA. Meanwhile, functional and network analysis was conducted to detect important signaling pathways and key genes with the Gene Expression Omnibus (GEO) dataset.

RESULTS

Our results showed that GLUT1 was over-expressed both in LUAD and LUSC. LUAD patients with high GLUT1 expression had a poor prognosis. Additionally, GLUT1 was related to B cell and neutrophil infiltration of LUAD. In LUSC, GLUT1 was correlated with tumor purity, B cell, CD8⁺ T cell, CD4⁺ T cell, macrophage, neutrophil, and dendritic cell infiltration. The GEO dataset analysis results suggested GLUT1 potentially participated in the p53 signaling pathway and metabolism of xenobiotics by cytochrome P450 and was associated with KDR, TOX3, AGR2, FOXA1, ERBB3, ANGPT1, and COL4A3 gene in LUAD and LUSC.

CONCLUSION

GLUT1 might be a potential biomarker for aggressive progression and poor prognosis in LUAD, and a therapeutic biomarker in LUSC.

Diffuse expression of MUC6 defines a distinct clinicopathological subset of pulmonary invasive mucinous adenocarcinoma

Invasive mucinous adenocarcinoma (IMA) of the lung is a unique variant of lung adenocarcinoma. Aberrant mucin expression is associated with cancer development and metastasis. However, the clinicopathological significance of mucin expression in IMA is not fully understood. Herein, we evaluated the clinicopathological, immunohistochemical, and molecular characteristics of 70 IMA tumors. EGFR, KRAS, GNAS, and TP53 mutations were assessed by PCR-based sequencing. Next-generation sequencing was used to assess cases without EGFR/KRAS mutations. A NanoString-based screening for fusions was performed in all IMAs without mitogenic driver mutations. Expression of mucins (MUC1, MUC2, MUC4, MUC5AC, and MUC6) was evaluated by immunohistochemistry and categorized as follows: negative (<10% of tumor cells), patchy expression (<90% of tumor cells), or diffuse expression (≥90% of tumor cells). Immunohistochemical testing for transcription factors (TTF-1, CDX2, HNF1β, HNF3α, HNF3β, and HNF4α) was also performed. As expected, KRAS mutations were the most common (in 67% of cases), followed by small numbers of other alterations. Patchy or diffuse expression of MUC1, MUC2, MUC4, MUC5AC, and MUC6 was observed in 52% or 6%, 3% or 0%, 30% or 3%, 26% or 73%, and 59% or 27% of cases, respectively. Furthermore, all IMAs were generally positive for HNF1β (100%), HNF3α (100%), HNF3β (100%), and HNF4α (99%) but were positive less often for TTF-1 (6%) and CDX2 (9%). Overall, there was no significant correlation between mucin expression and transcription factor expression. Unexpectedly, diffuse expression of MUC6 was significantly associated with KRAS-wild-type tumors (p = 0.0008), smaller tumor size (p = 0.0073), and tumors in female patients (p = 0.0359) in multivariate analyses. Furthermore, patients with tumors exhibiting diffuse MUC6 expression had significantly favorable outcomes. Notably, none of these patients died of the disease. Our data suggested that diffuse expression of MUC6 defines a distinct clinicopathological subset of IMA characterized by wild-type KRAS and possibly less aggressive clinical course.

A novel Tn antigen epitope-recognizing antibody for MUC1 predicts clinical outcome in patients with primary lung adenocarcinoma

Mucin 1 (MUC1) expression is upregulated in multiple types of cancer, including lung cancer. However, the conventional anti-MUC1 antibody is not useful for the differentiation of malignant lung tumors and benign lesions due to its limited specificity. Our previous study screened a novel epitope-defined antibody against cancer-associated sugar chain structures that specifically recognizes the MUC1 Tn antigen (MUC1-Tn ED Ab). In the present study, its potential utility as a diagnostic marker and therapeutic tool for lung adenocarcinoma (ADC) was examined. Immunohistochemical analysis of a lung ADC tissue microarray was performed using the MUC1-Tn ED Ab (clone SN-102), and the results were compared with those of another clone and commercially available MUC1 antibodies. The association between positive immunoreactivity of SN-102 and clinicopathologic factors was analyzed. Furthermore, the association between MUC1-Tn expression and epithelial-mesenchymal transition markers and radiological characteristics was analyzed. Moderate or high MUC1-Tn expression (MUC1-Tn-H) was observed in 138 (78.9%) of the 175 lung ADC cases. MUC1-Tn-H was associated with male sex, cigarette smoking, tumor extension, pleural invasion, and higher preoperative serum carcinoembryonic antigen and cytokeratin 19 fragment levels. Tumors with MUC1-Tn-H had higher consolidation/tumor ratios according to computed tomography and greater uptakes of ¹⁸F-fluorodeoxyglucose. A total of 46 (26.9%) of the tumors had mesenchymal features, and MUC1-Tn positivity was higher in the mesenchymal group than in the epithelial and intermediate groups (P<0.01 and P<0.01, respectively). Patients with tumors exhibiting MUC1-Tn-H had significantly shorter 5-year overall and disease-free survival times (P=0.011 and P<0.001, respectively). Additionally, MUC1-Tn-H was identified as an independent prognostic factor in multivariate analysis (P=0.024). MUC1-Tn is specific for lung cancer cells and can improve diagnostic capabilities. Additionally, it may be a potential therapeutic target in lung ADC.

Clinical associations of mucin 1 in human lung cancer and precancerous lesions

Mucin 1 (MUC1) is a cell membrane glycoprotein overexpressed in non-small cell lung cancer (NSCLC) and has been implicated in carcinogenesis of premalignant lung lesions. Thus, MUC1 has been a target of interest for vaccine strategies for lung cancer treatment and prevention. Here, we assessed MUC1 expression by immunohistochemistry using tumor samples from patients with biopsy-proven NSCLC. Levels of expression in areas of dysplasia, metaplasia, adenocarcinoma in situ, and carcinoma within the same tissue sample were characterized independently on a scale of 0-3 for paired comparison. We also assessed clinical data for correlations with MUC1 expression. Our analysis included 16 samples from patients with squamous lesions and 19 from patients with adenocarcinoma lesions. Among squamous lesions, MUC1 expression score was significantly increased in dysplastic compared with metaplastic areas (mean difference = 0.83, 95% confidence interval [CI], 0.21-infinity; P = 0.021). MUC1 expression was also increased among areas of squamous cell carcinoma versus dysplastic areas (mean difference = 0.44, 95% CI, -0.006-infinity; P = 0.052). In the adenocarcinoma lesions, MUC1 expression was increased in adenocarcinoma versus adenocarcinoma in situ, although not significantly (mean difference = 0.20, 95% CI, -0.055-infinity; P = 0.094). The increase in MUC1 expression with the progression of premalignant lung lesions to invasive carcinoma in patients with NSCLC supports MUC1 as a possible therapeutic target for the prevention and treatment of lung cancer.

Mucins in lung cancer: diagnostic, prognostic, and therapeutic implications

Aberrant expression of mucins is associated with cancer development and metastasis. An overexpression of few mucins contributes to oncogenesis by enhancing cancer cell growth and providing constitutive survival signals. This review focuses on the importance of mucins both in the normal bronchial epithelial cells and the malignant tumors of the lung and their contribution in the diagnosis and prognosis of lung cancer patients. During lung cancer progression, mucins either alone or through their interaction with many receptor tyrosine kinases mediate cell signals for growth and survival of cancer cells. Also, stage-specific expression of certain mucins, like MUC1, is associated with poor prognosis from lung cancer. Thus, mucins are emerging as attractive targets for developing novel therapeutic approaches for lung cancer. Several strategies targeting mucin expression and function are currently being investigated to control lung cancer progression.

Significance of MUC1 expression in biopsy specimens of submucosal invasive gastric carcinoma: The association with lymph node metastasis

Mucin 1, cell surface associated (MUC1) is a tumor-associated glycoprotein that has been reported to have an important role in lymphatic invasion and metastasis. The present study aimed to investigate the significance of MUC1 expression in endoscopic biopsy specimens of submucosal invasive gastric carcinomas and the association with lymph node metastasis. The clinicopathological features of 144 cases of surgically resected submucosal invasive gastric carcinomas and their paired endoscopic biopsy specimens were reviewed. Immunohistochemical staining for MUC1 was performed for the 144 endoscopic biopsy specimens. Positive MUC1 expression was identified in 70 (49%) cases. In addition, univariate analysis revealed that MUC1 expression was significantly associated with the presence of poorly-differentiated (P=0.001) and poorly-cohesive (P=0.015) carcinoma cells, undifferentiated type by Japanese classification (P<0.001), diffuse type of Lauren classification (P<0.001) and lymph node metastasis (P=0.024). By multivariate analysis, diffuse type of Lauren classification (P<0.001) and lymph node metastasis (P=0.035) were identified as independent factors for MUC1 expression. Furthermore, MUC1 expression (P=0.007), tumor size (P=0.018) and lymphatic invasion (P<0.001) were demonstrated to be independent factors for lymph node metastasis under multivariate analysis. In conclusion, the results of the present study indicated that positive MUC1 expression in endoscopic biopsy specimens may be a predictive factor of lymph node metastasis in submucosal invasive gastric carcinoma.

MUC1 enhances hypoxia-driven angiogenesis through the regulation of multiple proangiogenic factors

Pancreatic cancer is one of the most lethal malignancies due to its aggressive growth and rapid development of distant metastases. In this context, mucin 1 (MUC1) overexpression and hypoxia are frequently observed events. However, their functional relationship remains largely unknown. This study provides evidence that MUC1 is overexpressed by hypoxia and contributes to hypoxia-driven angiogenesis. Using the conditioned medium obtained from hypoxia-stressed AsPC1 cells treated with MUC1 siRNAs, we demonstrated that MUC1 enhanced the endothelial tube formation, proliferation and migration ability, which induced by hypoxia-conditioned medium (HCM). In addition, MUC1 was significantly induced by hypoxia, especially in the pancreatic cancer cells derived from metastatic tumors (AsPC1, HPAF2 or Capan1), and MUC1-cytoplasmic tail (MUC1-CT) accumulated in the nucleus under hypoxia. As noted in a previous report, MUC1-CT was recruited to genomic regions upstream of the connective tissue growth factor (CTGF) accompanied with β-catenin and p53, resulting in the hypoxic induction of CTGF. Moreover, hypoxia-induced MUC1 partially regulated two other hypoxia-inducible proangiogenic factors including vascular endothelial growth factor-A and platelet-derived growth factor-B. The neutralization assay revealed that endothelial tube formation induced by HCM was clearly suppressed by antibodies against these three factors, suggesting the importance of these factors in hypoxia-driven angiogenesis. In summary, this is the first report demonstrating a pivotal role of MUC1 in controlling the hypoxia-driven angiogenesis through the regulation of multiple proangiogenic factors in pancreatic cancer. Our findings provide the novel insights into the understanding of complex interactions between pancreatic cancer cells and tumor microenvironments.