Tumor volume and cancer stem cell expression as prognostic markers for high-dose loco-regional failure in head and neck squamous cell carcinoma - A DAHANCA 19 study

BACKGROUND AND PURPOSE

Reliable and accessible biomarkers for patients with Head and Neck Squamous Cell Carcinoma (HNSCC) are warranted for biologically driven radiotherapy (RT). This study aimed to investigate the prognostic value of putative cancer stem cell (CSC) markers, hypoxia, and tumor volume using loco-regional high-dose failure (HDF) as endpoint.

MATERIALS AND METHODS

Tumor tissue was retrieved from patients treated with primary chemo-(C-)RT and nimorazole for HNSCC in the Danish Head and Neck Cancer Study Group (DAHANCA) 19 study. Tumor volume, hypoxic classification, and expression of CSC markers CD44, SLC3A2, and MET were analyzed. For patients with eligible data on all parameters (n = 340), the risk of HDF following primary chemo-(C-)RT were analyzed by these biomarkers as a whole and stratified for p16-positive oropharynx (p16 + OPSCC) vs p16-negative (p16-) tumors (oral cavity, p16- oropharynx, hypopharynx and larynx).

RESULTS

Higher risk of HDF was seen for patients with larger primary and nodal volume (>25 cm3, Hazard Ratio (HR): 3.00 [95 % CI: 1.73-5.18]), high SLC3A2 (HR: 2.99 [1.28-6.99]), CD44 (>30 % positive, HR: 2.29 [1.05-5.00]), and p16- tumors (HR: 2.53 [1.05-6.11]). p16- tumors had a higher CSC marker expression than p16 + OPSCC. The factors associated with the highest risk of HDF were larger volume (HR: 3.29 [1.79-6.04]) for p16- tumors (n = 178) and high SLC3A2 (HR: 6.19 [1.58-24.23]) for p16 + OPSCC (n = 162).

CONCLUSION

Tumor volume, p16, and CSC markers are potential biomarkers for HDF for patients with HNSCC treated with (C-)RT. Lower expression of CSC in p16 + OPSCC may contribute to better tumor control.

[Inhibition of GAS5 promoted invasion, migration and epithelial-mesenchymal transition of colorectal cancer cells via miR-21/PTEN/Akt axis]

Objective: To explore the effect of growth arrest-specific5 (GAS5) inhibition on the proliferation, colony formation, invasion, migration andepithelial-mesenchymal transition(EMT), cancer cell stem of HCT-116 and its mechanism. Methods: The colorectal carcinoma (CRC) cell HCT116 was divided into blank control, negative control (NC), si-GAS5 and si-GAS5+ miR-21 inhibitor groups. The quantitative real-time polymerase chain reaction (qRT-PCR) was used to test the expressions of miR-21 and GAS5 at 48 h after transfection. The binding site of GAS5 and miR-21 was determined by luciferase reporter array. Cell proliferation ability was detected by CCK-8 assay. Cell colony ability was detected by colony formation assay. Cell invasion and migration abilities were detected by Transwell assay. Cell cycle and apoptosis were examined by flow cytometer (FCM). The protein levels of EMT associated factors including Snail, N-cadherin, vimentin, E-cadherin, stem cell related factors including CD44, SOX2, Oct2, and PTEN/Akt signal pathway associated factors were examined by western blotting. Results: The expression levels of miR-21 in blank, NC, si-GAS5 group were 1.00±0.10, 1.00±0.10, 1.80±0.20, the absorbance values were 0.51±0.02, 0.50±0.01 and 0.65±0.01, the cell clones were 90±4, 91±5, 200±8, the invaded cells were 118±3, 119±3, 150±4, the migrated cells were 110±2, 108±2, 127±2, the cell ratios in G(1) phase were (49.3±2.1)%, (50.1±2.0)% and (42.2±1.1)%, the cell ratios in S phase were (19.2±1.2)%, (20.2±1.1)% and (28.3±2.2)%, the cell apoptotic ratios were (14.4±2.2)%, (14.5±2.1)% and (7.2±1.3)%. These results indicated that inhibition of GAS5 up regulated the expression level of miR-21, promoted cell proliferation, invasion and migration, decreased G(1)-phase cells and increased S-phase cells, and suppressed cell apoptosis (P<0.05). Moreover, inhibition of GAS5 up regulated the expressions of Snail, N-cadherin, vimentin, Sox2, CD44, Oct2 and p-Akt in HCT-116 cells (P<0.05), while down regulated the expressions of E-cadherin and PTEN (P<0.05). Inhibition of miR-21 reversed the impact of GAS5 knockdown on PTEN/Akt signaling pathway (P<0.05). Conclusion: GAS5 can act as a competing endogenous RNA for miR-21, and down regulation of GAS5 can promote the development of CRC by activating the miR-21/PTEN/Akt signaling pathway and promoting the acquisition of EMT and tumor cell stemness.

Ionizing Radiation Promotes Epithelial-Mesenchymal Transition Phenotype and Stem Cell Marker in The Lung adenocarcinoma: In Vitro and Bioinformatic Studiesc

OBJECTIVE

Ionizing radiation (IR) is one of the major therapeutic approaches in the non-small cell lung cancer (NSCLC); however, it can paradoxically result in cancer progression likely through promoting epithelial-mesenchymal transition (EMT) and the cancer stem cell phenotype. Therefore, we aimed to determine whether IR promote EMT/CSC and to investigate the clinical relevance of EMT/CSC hallmark genes.

MATERIALS AND METHODS

In this experimental and bioinformatic study, A549 cell line was irradiated with a high dosage (6 Gy) or a fractionated regimen (2 Gy/day for 15 fractions). The EMT-related features, including cellular morphology, migratory and invasive capacities were evaluated using scratch assay and transwell migration/invasion assays. The mRNA levels of EMT-related genes (CDH1, CDH2, SNAI1 and TWIST1), stemness-related markers (CD44, PROM1, and ALDH1A1) and the CDH2/CDH1 ratio were evaluated via real-time polymerase chain reaction (PCR). The clinical significance of these genes was assessed in the lung adenocarcinoma (LUAD) samples using online databases.

RESULTS

Irradiation resulted in a dramatic elongation of cell shape and enhanced invasion and migration capabilities. These EMT-like alterations were accompanied with enhanced levels of SNAI1, CDH2, TWIST1, CD44, PROM1, and ALDH1A1 as well as an enhanced CDH2/CDH1 ratio. TCGA analysis revealed that, TWIST1, CDH1, PROM1 and CDH2 were upregulated; whereas, CD44, SNAI1 and ALDH1A1 were downregulated. Additionally, correlations between SNAI1-TWIST1, CDH2- TWIST1, CDH2-SNAI1, and ALDH1A1-PROM1 was positive. Kaplan-Meier survival analysis identified lower expression of CDH1, PROM1 and ALDH1A1 and increased expression of CDH2, SNAI1, and TWIST1 as well as CDH2/CDH1 ratio predict overall survival. Additionally, downregulation of ALDH1A1 and upregulation of CDH2, SNAI1 and CTWIST1 could predict a shorter first progression.

CONCLUSION

Altogether, these findings demonstrated that IR promotes EMT phenotype and stem cell markers in A549 cell line and these genes could function as diagnostic or prognostic indicators in LUAD samples.

Effects of Arf6 downregulation on biological characteristics of human prostate cancer cells

Objective

To evaluate the effects of Arf6 downregulation on human prostate cancer cells.

Materials and Methods

The effects of Arf6 downregulation on cell proliferation, migration, invasion and apoptosis were assessed by MTT, BrdU, scratch, Transwell assays and flow cytometry respectively. AKT, p-AKT, ERK1/2, p-ERK1/2 and Rac1 protein expressions were detected by Western blot.

Results

Downregulating Arf6 by siRNA interference suppressed the mRNA and protein expressions of Arf6. The proliferation capacities of siRNA group at 48h, 72h, and 96h were significantly lower than those of control group (P <0.05). The migration distance of siRNA group at 18h was significantly shorter than that of control group (P <0.01). The number of cells penetrating Transwell chamber membrane significantly decreased in siRNA group compared with that of control group (P <0.01). After 24h, negative control and normal control groups had similar apoptotic rates (P >0.05) which were both significantly lower than that of siRNA group (P <0.01). After Arf6 expression was downregulated, p-ERK1/2 and Rac1 protein expressions were significantly lower than those of control group (P <0.05).

Conclusion

Downregulating Arf6 expression can inhibit the proliferation, migration and invasion of prostate cancer cells in vitro, which may be related to ERK1/2 phosphorylation and Rac1 downregulation.

Evaluation of Impacts of Cellular Metabolism on the Migration of Ovarian Cancer Cells by Two in Vitro Assays: A Method Comparison Study

BACKGROUND

Alteration of metabolic pathways in cancer cells can intensely modulate their migration as an important step in invasion and metastasis. Ketogenic diet showed some contradictory results in cancer patients. In this study the impact of metabolic reprogramming of A2780CP as a model of ovarian cancer stem-like cells on cell migration by two in vitro methods: wound healing and soft agar colony-forming assays.

MATERIALS AND METHODS

short term and long term metabolic reprogramming were done by restriction of glucose to 250mg/L with or without enrichment with beta-hydroxybutyrate (5 milimolar) for 48 hours and 30 days, respectively. Wound healing assay was done and the wound ratio was calculated for 24 and 48 hours. Soft agar colony formation assay was also done in treated and control cells. For method comparison, ten biological replicates were analyzed in triplicate.

RESULTS

Migration of A2780CP ovarian cancer stem-like cells were significantly alleviated by long term glucose restriction but no significant changes were observed in short term study. Beta-hydroxybutyrate enrichment did not produce significant impacts on glucose restriction in short or long term studies.

CONCLUSION

The results of colony formation in soft agar and wound or scratch healing assay were in good correlation and convergence which could be used interchangeably in the investigation of metabolic reprogramming in cancer cells.

A modified method by differential adhesion for enrichment of bladder cancer stem cells

Purpose:

In a previous study the vaccine was effective against bladder cancer in a mouse model. However, a small portion of tumors regrew because the vaccine could not eliminate bladder cancer stem cells (CSCs). In this study, we showed a modified method for the isolation of bladder CSCs using a combination of differential adhesion method and serum-free culture medium (SFM) method.

Materials and Methods:

Trypsin-resistant cells and trypsin-sensitive cells were isolated from MB49, EJ and 5637 cells by a combination of differential adhesion method and SFM method. The CSCs characterizations of trypsin-resistant cells were verified by the flow cytometry, the western blotting, the quantitative polymerase chain reaction, the resistance to chemotherapy assay, the transwell assay, and the tumor xenograft formation assay.

Results:

Trypsin-resistant cells were isolated and identified in CSCs characters, with high expression of CSCs markers, higher resistance to chemotherapy, greater migration in vitro, and stronger tumorigenicity in vivo.

Conclusion:

Trypsin-resistant cells displayed specific CSCs properties. Our study showed trypsin-resistant cells were isolated successfully with a modified method using a combination of differential adhesion method and SFM method.

Salinomycin reduces stemness and induces apoptosis on human ovarian cancer stem cell

Objective

Cancer stem cells (CSCs) represent a subpopulation of undifferentiated tumorigenic cells thought to be responsible for tumor initiation, maintenance, drug resistance, and metastasis. The role of CSCs in drug resistance and relapse of cancers could significantly affect outcomes of ovarian cancer patient. Therefore, therapies that target CSCs could be a promising approach for ovarian cancer treatment. The antibiotic salinomycin has recently been shown to deplete CSCs. In this study, we evaluated the effect of salinomycin on ovarian cancer stem cells (OCSCs), both alone and in combination with paclitaxel (PTX).

Methods

The CD44⁺CD117⁺CSCs were obtained from the ascitic fluid of patients with epithelial ovarian cancer by using an immune magnetic-activated cell sorting system. OCSCs were treated with PTX and salinomycin either singly or in combination. Cell viability and apoptosis assays were performed and spheroid-forming ability was measured. The expression of sex determining region Y-box 2 (SOX2) and octamer-binding transcription factor 3/4 (OCT3/4) mRNA was determined using reverse transcription polymerase chain reaction, and protein expression was observed using western blot analysis.

Results

Treatment with salinomycin alone reduced the stemness marker expression and spheroid-forming ability of OCSCs. Treatment with PTX alone did not decrease the viability of OCSCs. Treatment with a combination of salinomycin decreased the viability of OCSCs and promoted cell apoptosis. The enhancement of combination treatment was achieved through the apoptosis as determined by annexin V/propidium iodide (PI) staining, caspase-3 activity, and DNA fragmentation assay.

Conclusion

Based on our findings, combining salinomycin with other anti-cancer therapeutic agents holds promise as an ovarian cancer treatment approach that can target OCSCs.