MicroRNA-33b inhibits tumor cell growth and is associated with prognosis in colorectal cancer patients

Purpose

To explore the role of miR-33b in colorectal cancer (CRC) and the correlation between its expression and prognosis.

Methods

The expressions of miR-33b between CRC tissues and normal tissues were measured by real-time PCR. The effects of miR-33b on cell proliferation and cell cycle progression were detected by MTT assay, colony formation assay and flow cytometry. The potential regulations of miR-33b on multiple genes expression were verified by Western blot. Furthermore, the association of miR-33b with CRC clinicopathologic features and prognosis was analyzed by Chi-squared test and Kaplan–Meier tests.

Results

MiR-33b was downregulated in CRC compared with normal colorectal samples and miR-33b inhibited tumor cell growth and induced cell cycle arrest. Western blot assays and correlation analysis showed that miR-33b could regulate multiple growth-related genes. Moreover, the expression of miR-33b was associated with TNM stage and tumor size, and CRC patients with high miR-33b expression had a better prognosis.

Conclusion

Our data suggest that miR-33b functions as a tumor suppressor gene in CRC through regulating cell proliferation and cell cycle.

     

Single-Cell RNA-Sequencing in Glioma

Purpose of Review

In this review, we seek to summarize the literature concerning the use of single-cell RNA-sequencing for CNS gliomas.

Recent Findings

Single-cell analysis has revealed complex tumor heterogeneity, subpopulations of proliferating stem-like cells and expanded our view of tumor microenvironment influence in the disease process.

Summary

Although bulk RNA-sequencing has guided our initial understanding of glioma genetics, this method does not accurately define the heterogeneous subpopulations found within these tumors. Single-cell techniques have appealing applications in cancer research, as diverse cell types and the tumor microenvironment have important implications in therapy. High cost and difficult protocols prevent widespread use of single-cell RNA-sequencing; however, continued innovation will improve accessibility and expand our of knowledge gliomas.

     

Stromal markers AKR1C1 and AKR1C2 are prognostic factors in primary human breast cancer

Background

Stromal fibroblasts influence tumor growth and progression. We evaluated two aldo–keto reductases, AKR1C1 and AKR1C2, in stromal fibroblasts and carcinoma cells as prognostic factors in primary human breast cancer. They are involved in intratumoral progesterone metabolism.

Methods

Immunohistochemistry was performed on tissue microarrays from 504 core biopsies from breast cancer patients. Primary endpoints were disease-free (DFS) and overall (OS) survival.

Results

AKR1C1 and AKR1C2 expression in fibroblasts and tumor cells correlated with favorable tumor characteristics, such as small tumor size and negative nodal status. In univariate analysis, AKR1C1 expression in carcinoma cells correlated positively with DFS und OS; AKR1C2 expression in both fibroblasts and tumor cells also showed a positive correlation with DFS and OS. In multivariate analysis, AKR1C1 expression in carcinoma cells was an independent prognostic marker.

Conclusion

It can be assumed that our observations are due to the independent regulatory function of AKR1C1/2 in progesterone metabolism and therefore provide a basis for new hormone-based therapy options for breast cancer patients, independent of classic hormone receptor status.

     

What Is the Future of Circulating Tumor Cells in Colorectal Cancer?

Purpose of Review

To introduce recent progress on circulating tumor cell (CTC) research in colorectal cancer (CRC) and to highlight clinical application of CTCs from detection to assessment of treatment response.

Recent Findings

CTC biological characteristics in CRC play an important role in the detection of CTCs. The in vitro culture of CTCs from CRC patients (cell lines and organoids) can potentially facilitate rapid drug testing and treatment prediction. CTC detection should be standardized with improved detection rate in CRC; further, clinical investigation is still needed to clarify its potential as a tool for early CRC detection, a predictive and prognostic marker to ultimately guide treatment.

Summary

Gaining an improved understanding of CTCs characteristics and ultimately, integration of CTC detection and utilization of CTCs may lead to optimized tumor treatment and facilitate precision medicine.

     

The glycosyltransferase ST6Gal-I is enriched in cancer stem-like cells in colorectal carcinoma and contributes to their chemo-resistance

Purpose

Presence of cancer stem cells (CSCs) contributes to tumor outgrowth, chemo-resistance and relapse in some cancers including colorectal carcinoma (CRC). The current characterization methods of CSCs in CRC only allows enrichment of CSCs but not their purification. Recent reports showed that ST6 beta-galactoside alpha-2,6-sialyltransferase 1 (ST6Gal-I) plays an essential role in protecting tumor cells against harsh environment like oxidative stress and nutrient deprivation. Therefore, whether ST6Gal-I may be highly expressed in CSCs or whether it may enhance resistance of tumor cells to chemotherapy deserves exploration.

Method

ST6Gal-I levels were determined in CRC specimens, compared to paired normal colorectal tissue, and examined in CD133+ vs CD133? CRC cells, and CD44+ vs CD44? CRC cells. ST6Gal-I levels and their association with patient survival were examined. In vivo, 2 CRC cell lines Caco-2 and SW48 were transduced with two lentiviruses, one lentivirus carrying a green fluorescent protein reporter and a luciferase reporter under a cytomegalovirus promoter to allow tracing tumor cells by both fluorescence and luciferase activity, and one lentivirus carrying a nuclear red fluorescent protein under the control of ST6Gal-I promoter to allow separation of ST6Gal-I+ vs ST6Gal-I? CRC cells. Tumor sphere formation, resistance to fluorouracil-induced apoptosis, and frequency of tumor formation after serial adoptive transplantation were done on ST6Gal-I+ vs ST6Gal-I? CRC cells.

Result

ST6Gal-I levels were significantly upregulated in clinically obtained CRC specimens, compared to paired normal colorectal tissue. Poorer patient survival was detected in ST6Gal-I-high CRC, compared to ST6Gal-I-low subjects. Higher levels of ST6Gal-I were detected in CD133+ CRC cells than CD133? CRC cells, and in CD44+ CRC cells than in CD44? CRC cells. Compared to ST6Gal-I? CRC cells, ST6Gal-I+ CRC cells generated significantly more tumor spheres in culture, were more resistant to fluorouracil-induced apoptosis likely through upregulating cell autophagy, and generated tumor more frequently after serial adoptive transplantation.

Conclusion

ST6Gal-I may be highly expressed in the cancer stem-like cells in CRC and enhances cancer cell resistance to chemotherapy.

     

Clinicopathologic parameters associated with postoperative complications and risk factors for tumor recurrence and mortality after tumor resection of patients with colorectal cancer

Objective

To delineate the association of postoperative complications with clinicopathologic factors and to identify risk factors for tumor recurrence and mortality after tumor resection in patients with colorectal cancer (CRC).

Methods

The clinical data of 1144 patients with CRC who underwent surgical intervention between 2003 and 2013 were retrieved. Correlations of postoperative complications with clinicopathologic factors were examined using univariate analysis. Risk factors for tumor recurrence and mortality of the patients after tumor resection were identified using multivariate Cox proportional hazards models. Time to relapse and overall survival were analyzed using log-rank test of Kaplan–Meier analysis.

Results

Blood carcinoembryonic antigen (CEA) significantly correlated with early symptoms, preoperative manifestations, and tumor pathology. Low differentiation grade of tumor increased the risk of recurrence after surgery in all patients with CRC. In the same cohort of patients, elevated blood CEA, low differentiation grade of tumor, laparotomy, smoking history, and TNM stage IV and III increased the mortality risk after tumor resection. In patients with advanced colon cancer, risk for postoperative mortality was increased by blood CEA, advanced tumor stage, and low tumor differentiation grade; while in those with advanced rectal cancer, blood CEA, pathologic type other than mucinous/adenocarcinoma, and laparotomy were identified as significant risk factors. In both groups of patients, postoperative chemotherapy significantly reduced the risk of mortality.

Conclusions

The present work has identified clinical factors increasing the risk of recurrence as well as mortality after surgery in more than 1,000 patients with CRC. Postoperative chemotherapy is associated with a significant reduction in the risk of mortality. All of these findings should provide insights into the better management of critically ill patients with CRC.

     

Magnetic resonance imaging identifies early effects of sunitinib treatment in human melanoma xenografts

Background

Antiangiogenic treatment may change the tumor microenvironment and hence influence the effect of conventional therapies. The potential of diffusion weighted magnetic resonance imaging (DW-MRI) and dynamic contrast enhanced MRI (DCE-MRI) in assessing microenvironmental effects of sunitinib treatment was investigated in this preclinical study.

Methods

Sunitinib-treated and untreated A-07 tumors were subjected to DW-MRI and DCE-MRI, and parametric images of ADC and K^trans were produced. Microvascular density, hypoxic fraction, and necrotic fraction were assessed from immunohistochemical preparations, and tumor interstitial fluid pressure (IFP) was assessed with probe measurement.

Results

Sunitinib-treated tumors showed reduced microvascular density, increased hypoxic fraction, increased necrotic fraction, increased ADC, and reduced K^trans, but did not differ from untreated tumors in growth rate and IFP.

Conclusions

Sunitinib treatment affected the tumor microenvironment without affecting tumor size. DW-MRI and DCE-MRI were sensitive to the sunitinib-induced changes in the tumor microenvironment.

     

Cancer–adipose tissue interaction and fluid flow synergistically modulate cell kinetics,HER2 expression,and trastuzumab efficacy in gastric cancer

Background

Early local tumor invasion in gastric cancer results in likely encounters between cancer cells and submucosal and subserosal adipose tissue, but these interactions remain to be clarified. Microenvironmental mechanical forces, such as fluid flow, are known to modulate normal cell kinetics, but the effects of fluid flow on gastric cancer cells are poorly understood. We analyzed the cell kinetics and chemosensitivity in gastric cancer using a simple in vitro model that simultaneously replicated the cancer–adipocyte interaction and physical microenvironment.

Methods

Gastric cancer cells (MKN7 and MKN74) were seeded on rat adipose tissue fragment-embedded discs or collagen discs alone. To generate fluid flow, samples were placed on a rotatory shaker in a CO₂ incubator. Proliferation, apoptosis, invasion, and motility-related molecules were analyzed by morphometry and immunostaining. Proteins were evaluated by western blot analysis. Chemosensitivity was investigated by trastuzumab treatment.

Results

Adipose tissue and fluid flow had a positive synergistic effect on the proliferative potential and invasive capacity of gastric cancer cells, and adipose tissue inhibited apoptosis in these cells. Adipose tissue upregulated ERK1/2 signaling in gastric cancer cells, but downregulated p38 signaling. Notably, adipose tissue and fluid flow promoted membranous and cytoplasmic HER2 expression and modulated chemosensitivity to trastuzumab in gastric cancer cells.

Conclusion

We have demonstrated that cancer–adipocyte interaction and physical microenvironment mutually modulate gastric cancer cell kinetics. Further elucidation of the microenvironmental regulation in gastric cancer will be very important for the development of strategies involving molecular targeted therapy.

     

miR-328 mediates a metabolic shift in colon cancer cells by targeting SLC2A1/GLUT1

Purpose

Increasing evidence shows that altered metabolism is a critical hallmark in colon cancer. There is a strong need to explore the molecular mechanisms underlying cancer metabolism. Whether the aberrant expression of microRNAs contributes to cancer metabolism is not fully understood. miR-328 is a putative potential target of SLC2A1, but the regulating mechanism between them remains unknown. We have examined whether miR-328 directly regulates SLC2A1/GLUT1 expression in colon cancer cells.

Methods

We performed in silico bioinformatic analyses to identify miR-328-mediated molecular pathways and targets. We also performed luciferase assays and western blot analyses in LOVO and SW480 colon cancer cell lines. In addition, we assessed miR-328 expression in 47 paired tumor and normal tissue specimens from resected colon cancer patients.

Results

Luciferase reporter assays showed that miR-328 directly targeted SLC2A1 3′-untranslated region (UTR), with a significant decrease in luciferase activity in both LOVO and SW480 cell lines. These results were validated by western blot. miR-328 expression was significantly downregulated in tumor tissue compared with paired normal tissue.

Conclusions

Our results show that miR-328 targets SLC2A1/GLUT1. We suggest that miR-328 may be involved in the orchestration of the Warburg effect in colon cancer cells. Furthermore, miR‐328 expression is reduced in colon cancer patients and thus inversely correlates with the classically reported upregulated SLC2A1/GLUT1 expression in tumors.

     

Alteration of tumor suppressor BMP5 in sporadic colorectal cancer: a genomic and transcriptomic profiling based study

Background

Although the genetic spectrum of human colorectal cancer (CRC) is mainly characterized by APC, KRAS and TP53 mutations, driver genes in tumor initiation have not been conclusively demonstrated. In this study, we aimed to identify novel markers for CRC.

Methods

We performed exome analysis of sporadic colorectal cancer (sCRC) coding regions to screen loss of function (LoF) mutation genes, and carried out systems-level approaches to confirm top rank gene in this study.

Results

We identified loss of BMP5 is an early event in CRC. Deep sequencing identified BMP5 was mutated in 7.7% (8/104) of sCRC samples, with 37.5% truncating mutation frequency. Notably, BMP5 negative expression and its prognostic value is uniquely significant in sCRC but not in other tumor types. Furthermore, BMP5 expression was positively correlated with E-cadherin in CRC patients and its dysregulation play a vital role in epithelial-mesenchymal transition (EMT), thus triggering tumor initiation and development. RNA sequencing identified, independent of BMP/Smads pathway, BMP5 signaled though Jak-Stat pathways to inhibit the activation of oncogene EPSTI1.

Conclusions

Our result support a novel concept that the importance of BMP5 in sCRC. The tumor suppressor role of BMP5 highlights its crucial role in CRC initiation and development.

     

Knockdown of ST6Gal-I increases cisplatin sensitivity in cervical cancer cells

Background

Sialyltransferase I (ST6Gal-I) is an enzyme involved in tumor metastasis that processes sialic acid precursors into their mature form, enabling them to regulate gene expression. However, the effect of ST6Gal-I on the biological behavior of cancer cells remain unclear. This study was the first to demonstrate the influence of ST6Gal-I on cisplatin sensitivity in cervical cancer cells.

Methods

Knockdown of ST6Gal-I was performed by shRNA and HeLa cells combination with cisplatin were tested.

Results

We showed that down-regulation of ST6Gal-I promoted cell apoptosis and inhibited proliferation and invasion in cervical cancer cells. Knockdown of ST6Gal-I by RNA interference increased the sensitivity of HeLa cells to cisplatin in vitro, and reduced tumor volume and suppressed subcutaneous tumor growth in response to cisplatin treatment in a xenograft mouse model in vivo.

Conclusions

The results provide new information that ST6Gal-I plays an important role in several biological or pathological processes including drug resistance in cervical cancer and may be a potential therapeutic target to improve the response to chemotherapy in cervical cancer patients.

     

Obesity,Dietary Factors,Nutrition, and Breast Cancer Risk

Purpose of Review

To synthesize the critical role of obesity-associated inflammation, dietary factors, and nutrition in determining breast cancer risk.

Recent Findings

Obesity-associated inflammation is strongly linked to breast cancer risk and progression, largely via two processes: inflammatory pathways and dysregulated metabolism. Cytokine production in excess adipose tissues creates a chronic inflammatory microenvironment, which favors tumor development. Lifestyle factors, including diet, have long been recognized as important determinants of breast cancer risk and mortality.

Summary

Obesity increases the risk of developing breast cancer in both pre- and postmenopausal women and also negatively affects breast cancer recurrence and survival. Poor dietary habits characterized by the high intake of refined starches, sugar, and both saturated and trans-saturated fats, as well as the low intake of omega-3 fatty acids, natural antioxidants, and fiber, modulate inflammation and, thereby, appear to be linked to increased risk of breast cancer and mortality.

     

Are disseminated tumor cells in bone marrow and tumor-stroma ratio clinically applicable for patients undergoing surgical resection of primary colorectal cancer? The Leiden MRD study

Purpose

Current TNM staging does not appropriately identify high-risk colorectal cancer (CRC) patients. The aim of this study was to evaluate whether the presence of disseminated tumor cells (DTCs) in the bone marrow (BM) and the presence of stroma in the primary tumor, i.e., the tumor-stroma ratio (TSR), in patients undergoing surgical resection of primary CRC provides information relevant for disease outcome.

Methods

Patients with primary CRC (n?=?125), consecutively admitted for curative resection between 2001 and 2007, were included in the study. All patients underwent BM aspiration before surgery. Detection of tumor cells was performed using immunocytochemical staining for cytokeratin (CK-ICC). The TSR was determined on diagnostic H&E stained sections of primary tumors.

Results

DTCs were detected in the BM of 23/125 patients (18 %). No association was found between BM status and overall survival (HR 0.97 (95 % CI 0.45–2.09), p?=?0.93). Also, no significant difference was found in their 5-year survival rate (resp. 72 % and 68 % for BM-positive versus BM-negative patients). The TSR was found to be associated with a worse overall survival (HR 2.16, 95 % CI 1.02–4.57, p?=?0.04) with 5-year survival rates of 84 % versus 62 % for stroma-low and stroma-high patients, respectively. No relation was found between the presence of DTCs and TSR.

Conclusions

Our data indicate that the presence of DTCs in the BM of CRC patients is not associated with disease outcome. The TSR was, however, found to be associated with a worse overall survival, which indicates that for CRC the tumor microenvironment plays an important role in its behavior and prognosis.

     

Overexpression of forkhead box protein M1 (FOXM1) plays a critical role in colorectal cancer

Background

The forkhead box M1 (FOXM1), an important regulator of cell differentiation and proliferation, is overexpressed in a number of aggressive human carcinomas. However, the clinical significance of FOXM1 signaling in human colorectal cancer (CRC) pathogenesis remains unknown. The aim of this study was to evaluate the role of FOXM1 in CRC tumorigenesis.

Methods

We investigated FOXM1 expression in 103 cases of primary CRC and matched normal tissue specimens and explored the underlying mechanisms of altered FOXM1 expression and the impact of this altered expression on CRC proliferation and metastasis using in vitro models of CRC.

Results

The results showed that high expression of FOXM1 staining was 85.44 % (88/103) in 103 cases of CRC and 20.39 % (21/103) in 103 cases of adjacent non-cancerous tissue samples; the difference of FOXM1 expression between two groups was statistically significant (P < 0.001). Silencing of FOXM1 inhibited the proliferation of CRC cells, and the invasion and migration of CRC cells were distinctly suppressed. Furthermore, FOXM1 knockdown led to substantial reductions in VEGF-A levels in CRC cell lines.

Conclusions

Our data suggest that the pathogenesis of CRC maybe mediated by FOXM1, and FOXM1 could represent selective targets for the molecularly targeted treatments of CRC.

     

Inflammation and Colorectal Cancer

Purpose of Review

Colorectal cancer (CRC) is the fourth most common cancer in both men and women in the USA, resulting in over 55,000 deaths annually. Environmental and genetic factors influence the development of CRC, and inflammation is a critical hallmark of cancer that may arise from a variety of factors. While patients with inflammatory bowel disease (IBD) have a higher risk of developing CRC, sporadic CRCs may engender or be potentiated by inflammation as well. In this review, we focus on recent advances in basic and translational research utilizing murine models to understand the contribution of inflammatory signaling pathways to CRC.

Recent Findings

We discuss advances in the utility of three-dimensional enteroid/colonoid/tumoroid cultures to understand immune-epithelial interactions in CRC, as well as the potential for utilizing patient-derived tumoroids for personalized therapies.

Summary

This review underscores the importance of understanding the complex molecular mechanisms underlying inflammation in sporadic CRC and highlights up-and-coming or new avenues for CRC biomarkers or therapies.