Nonadhesive Culture System Research Articles

Gene Expression Patterns of Colorectal Cancer Stem Cells Following Ibuprofen and Hyperthermia Treatment.

Cancer stem cells (CSCs) substantially influence the development of colorectal cancer (CRC), metastasis, relapse, and resistance to therapy. Ibuprofen and hyperthermia can be effective in the treatment of cancer. Herein, we evaluated the effects of hyperthermia and ibuprofen on the isolated-CSCs of CRC. This experimental study was conducted between Sep 2020 and Jan 2022 at the Department of Pathology, School of Medicine, Shiraz University of Medical Sciences, Iran. A non-adhesive culture system was used to isolate CSCs from HT-29 cells. To confirm the stemness nature of isolated-CSCs, the expression of stemness genes and protein markers was evaluated by quantitative Real-time PCR (qRT-PCR) and flow cytometry assay. The isolated-CSCs were treated with hyperthermia and ibuprofen. The cell viability was determined by MTT assay and trypan blue staining. The expression of stemness, proliferation, Wnt signaling pathway and apoptosis genes was assessed by qRT-PCR. CSCs were isolated within 14 days. The expression of CD-133 marker and OCT3/4, C-MYC, KLF4, and NANOG genes in isolated-CSCs was higher than HT-29 cells (P<0.05). Cell viability of treated-CSCs were considerably reduced (P<0.05). Hperthermia reduced the expression of OCT3/4, NANOG, PCNA, WNT1 and CTNNB1 genes and increased the expression of P53, BAX, and KLF4 genes (P<0.05). Ibuprofen decreased the expression of OCT3/4, BCL2, NANOG, PCNA, WNT1, and CTNNB1 genes and increased the expression of P53, BAX, and KLF4 genes in treated-CSCs (P<0.05). Hyperthermia and ibuprofen treatment demonstrate an inhibitory effect on colorectal CSCs. However, using combination therapy is remaining to be tested.

The Effect of Placenta Growth Factor Knockdown on hsa-miR-22-3p, hsa-let-7b-3p, hsa-miR-451b, and hsa-mir-4290 Expressions in MKN-45- derived Gastric Cancer Stem-like Cells

Background: Placental growth factor is involved in human gastric cancer initiation and progression through stimulating the proliferation, angiogenesis, invasion and metastasis of cancerous cells. Previous studies indicate that the expression profiles of hsa-miR-22-3p, hsa-let-7b-3p, hsa-miR-451b, and hsa-mir-4290 change in MKN-45- derived gastric cancer stem-like cells. Therefore, this study aims to investigate the effect of PlGF knockdown on hsa-miR-22-3p, hsa-let-7b-3p, hsa-miR-451b, and hsa-mir-4290 expressions in MKN-45-derived gastric cancer stem-like cells.Methods: We used a non-adhesive culture system to derive the cancer stem-like cells from MKN-45 cells. PlGF gene silencing was performed by PlGF-specific siRNA. The transcript of PlGF and miRNAs were measured by real-time RT-PCR. We conducted bioinformatics analyses with the online software programs TargetScan, miRanda, miRWalk, PicTar, and the Database for Annotation, Visualization, and Integrated Discovery tools to predict miRNAs’ targets and their signaling pathways.Results: hsa-let-7b-3p had a 2.28-fold up-regulation, whereas we observed downregulation of hsa-mir-451b (25%), hsa-mir-4290 (34%), and hsa-mir-22-3p (9%). Bioinformatics analysis results indicated that the miRNA target genes TGF-β, MAPK, and Wnt, and hedgehog signaling pathways contributed to cancer initiation and progression by influencing different cellular behaviors.Conclusion: We suggest that PlGF signaling may influence miRNA expression profiles in MKN-45-derived cancer stem-like cells, which can influence the expressions of different genes and signaling pathways. However, more empirical studies should determine the exact effect of PlGF knockdown on the expression of miRNA targets in cancer stem-like cells to locate their actual gene targets.

The molecular and clinical verification of therapeutic resistance via the p38 MAPK-Hsp27 axis in lung cancer.

Treatment failure followed by relapse and metastasis in patients with non-small cell lung cancer is often the result of acquired resistance to cisplatin-based chemotherapy. A cancer stem cell (CSC)-mediated anti-apoptotic phenomenon is responsible for the development of drug resistance. The underlying molecular mechanism related to cisplatin resistance is still controversial, and a new strategy is needed to counteract cisplatin resistance. We used a nonadhesive culture system to generate drug-resistant spheres (DRSPs) derived from cisplatin-resistant H23 lung cancer cells. The expressions of drug-resistance genes, properties of CSCs, and markers of anti-apoptotic proteins were compared between control cells and DRSPs. DRSPs exhibited upregulation of cisplatin resistance-related genes. Gradual morphological alterations showing epithelial-to-mesenchymal transition phenomenon and increased invasion and migration abilities were seen during induction of DRSPs. Compared with control cells, DRSPs displayed increased CSC and anti-apoptotic properties, greater resistance to cisplatin, and overexpression of p-Hsp27 via activation of p38 MAPK signaling. Knockdown of Hsp27 or p38 decreased cisplatin resistance and increased apoptosis in DRSPs. Clinical studies confirmed that the expression of p-Hsp27 was closely associated with prognosis. Overexpression of p-Hsp27 was usually detected in advanced-stage patients with lung cancer and indicated short survival.SummaryDRSPs were useful for investigating drug resistance and may provide a practical model for studying the crucial role of p-Hsp27 in the p38 MAPK–Hsp27 axis in CSC-mediated cisplatin resistance. Targeting this axis using siRNA Hsp27 may provide a treatment strategy to improve prognosis and prolong survival in lung cancer patients.

Silencing stem cell factor attenuates stemness and inhibits migration of cancer stem cells derived from Lewis lung carcinoma cells.

Stem cell factor (SCF) plays an important role in tumor growth and metastasis. However, the function of SCF in regulating stemness and migration of cancer stem cells (CSCs) remains largely undefined. Here, we report that non-adhesive culture system can enrich and expand CSCs derived from Lewis lung carcinoma (LLC) cells and that the expression level of SCF in CSCs was higher than those in LLC cells. Silencing SCF via short hairpin (sh) RNA lentivirus transduction attenuated sphere formation and inhibited expressions of stemness genes, ALDH1, Sox2, and Oct4 of CSCs in vitro and in vivo. Moreover, SCF-silenced CSCs inhibited the migration and epithelial-mesenchymal transition, with decreased expression of N-cadherin, Vimentin, and increased expression of E-cadherin in vitro and in vivo. Finally, SCF-short hairpin RNA (shRNA) lentivirus transduction suppressed tumorigenicity of CSCs. Taken together, our findings unraveled an important role of SCF in CSCs derived from LLC cells. SCF might serve as a novel target for lung cancer therapy.

Enrichment and characterization of cancer stem cells from a human non-small cell lung cancer cell line.

Tumor cells from the same origin comprise different cell populations. Among them, cancer stem cells (CSCs) have higher tumorigenicity. It is necessary to enrich CSCs to determine an effective way to suppress and eliminate them. In the present study, using the non-adhesive culture system, tumor spheres were successfully generated from human A549 non-small cell lung cancer (NSCLC) cell line within 2 weeks. Compared to A549 adherent cells, sphere cells had a higher self-renewal ability and increased resistance to cytotoxic drugs. Sphere cells were more invasive and expressed stem cell markers including octamer‑binding transcription factor 4 (Oct4) and sex-determining region Y-box 2 (Sox2) at high levels. CD133, a disputed marker of lung CSCs, was also upregulated. Tumor sphere cells showed higher tumorigenic ability in vivo, indicating that more CSCs were enriched in the sphere cells. More blood vessels were formed in the tumor generated by sphere cells suggesting the interaction between CSCs and blood vessel. A reliable model of enriching CSCs from the human A549 NSCLC cell line was established that was simple and cost-effective compared to other methods.

Doxycycline Induces Apoptosis and Inhibits Proliferation and Invasion of Human Cervical Carcinoma Stem Cells.

BackgroundCancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in cervical carcinoma. Reagents that can suppress the proliferation and differentiation of CSCs would provide new opportunities to fight against tumor recurrence. Doxycycline has been reported as a potential anti-cancer compound. However, few studies investigated its inhibitory effect against cervical cancer stem cells.MethodsHeLa cells were cultured in cancer stem cell conditional media in a poly-hema-treated dish. In this non-adhesive culture system, HeLa cells were treated with cisplatin until some cells survived and formed spheroids, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every three days for five times. The tumor xenografts with CSC enrichment were cultured in cancer stem cell specific medium again to form tumorsphere, which we called HeLa-CSCs. Expression of cancer stem cell markers in HeLa-CSCs was measured by flow cytometry and qPCR. HeLa-CSCs were then treated with doxycycline. Proliferation and differentiation rates were determined by the size of spheres formed in vitro and tumor formed in vivo.ResultsWe developed a new strategy to selectively enrich CSCs from human cervical carcinoma cell line HeLa, and these HeLa-CSCs are CD133+/CD49f+ cell populations with significantly enhanced expression of stem cell markers. When these HeLa-CSCs were treated with doxycycline, the colony formation, proliferation, migration and invasion, and differentiation were all suppressed. Meanwhile, stem cell markers SOX-2, OCT-4, NANOG, NOTCH and BMI-1 decreased in doxycycline treated cells, so as the surface markers CD133 and CD49f. Furthermore, proliferation markers Ki67 and PCNA were also decreased by doxycycline treatment in the in vivo xenograft mouse model.ConclusionsCancer stem cells are enriched from sphere-forming and chemoresistant HeLa-derived tumor xenografts in immunodeficient mice. Doxycycline inhibits proliferation, invasion, and differentiation, and also induces apoptosis of these HeLa-CSCs in vitro and in vivo.

Morusin inhibits glioblastoma stem cell growth in vitro and in vivo through stemness attenuation, adipocyte transdifferentiation, and apoptosis induction

Glioblastoma multiforme (GBM) cancer stem cells (GSCs) are responsible for the progression and recurrence of GBM after conventional therapy. Morusin possesses anti-cancer activity in vitro. The purpose of this study is to confirm the growth inhibition effect of morusin on human GSCs growth in vitro and in vivo and to explore the possible mechanism of its activity. Human GSCs were enriched under nonadhesive culture system, and characterized through neurosphere formation, toluidine blue staining, immunofluorescence staining, Western blotting analysis of stemness markers of CD133, nestin, Sox2 and Oct4, and tumorigenecity in vivo; the growth inhibition effect of morusin on human GSCs in vitro and in vivo were tested by cell cytotoxicity, neurosphere formation inhibition, adipogenic differentiation, apoptosis induction, and tumor growth inhibition in vivo assays. The potential molecular mechanisms underlying the growth inhibition effect of morusin on GSCs in vitro and in vivo were investigated with Western blotting evaluation of stemness, adipogenic, and apoptotic proteins in morusin treated GSCs and tumor tissues. GSCs enriched under nonadhesive culture system possess stemness characterstics; Morusin inhibited GSCs growth in vitro and in vivo, it reduced stemness of GSCs, induced them adipocyte-like transdifferention and apoptosis. Morusin has the potential to inhibit human GSCs growth in vitro and in vivo through stemness attenuation, adipocyte transdifferentiation, and apoptosis induction.

Enrichment and characterization of cancer stem-like cells from a cervical cancer cell line

Cancer stem cells (CSCs) are proposed to be responsible for tumor recurrence, metastasis and the high mortality rate of cancer patients. Isolation and identification of CSCs is crucial for basic and preclinical studies. However, as there are currently no universal markers for the isolation and identification of CSCs in any type of cancer, the method for isolating CSCs from primary cancer tissues or cell lines is costly and ineffective. In order to establish a reliable model of cervical cancer stem cells for basic and preclinical studies, the present study was designed to enrich cervical cancer CSCs using a nonadhesive culture system and to characterize their partial stemness phenotypes. Human cervical cancer cells (HeLa) were cultured using a nonadhesive culture system to generate tumor spheres. Their stemness characteristics were investigated through colony formation, tumor sphere formation, self-renewal, toluidine blue staining, chemoresistance, invasion assays, reverse transcription-polymerase chain reaction, immunofluorescence staining of putative stem cell markers, including octamer-binding transcription factor 4, SRY-box 2 and aldehyde dehydrogenase 1 family, member A1, and adipogenic differentiation induction. Typical tumor spheres were formed within 5–7 days under this nonadhesive culture system. Compared with the adherent parental HeLa cells, the colony formation capacity, self-renewal potential, light cell population, cell invasion, chemoresistance and expression of putative stem cell markers of the tumor sphere cells increased significantly, and a subpopulation of tumor sphere cells were induced into adipogenic differentiation. Using the nonadhesive culture system, a reliable model of cervical cancer stem cells was established, which is inexpensive, effective and simple compared with the ultra-low attachment serum free culture method. The stemness characteristics of the tumor sphere HeLa cells mirrored the CSC phenotypes. This CSC model may be useful for basic and preclinical studies of cervical cancer and other types of cancer.

Bufalin inhibits the differentiation and proliferation of human osteosarcoma cell line hMG63-derived cancer stem cells

Cancer stem cells (CSCs) play an important role in drug resistance of tumor and are responsible for high recurrence rates. Agents that can suppress the proliferation and differentiation of CSCs would provide new opportunity to fight against tumor recurrence. In this study, we developed a new strategy to enrich CSCs in human osteosarcoma cell line hMG63. Using these CSCs as model, we tested the effect of bufalin, a traditional Chinese medicine, on the proliferation and differentiation of CSCs. hMG63 cells were cultured in poly-HEMA-treated dish and cancer stem cell-specific medium. In this nonadhesive culture system, hMG63 formed spheres, which were then collected and injected into the immunodeficient mice. Cisplatin was administered every 3 days for five times. The enriched xenograft tumors were cultured in cancer stem cell-specific medium again to form tumor spheres. Expression of cancer stem cell markers of these cells was measured by flow cytometry. These cells were then treated with bufalin, and the proliferation and differentiation ability were indicated by the expression level of molecular markers and the formation of sphere again in vitro. We obtained a low CD133+/CD44 cell population with high-level stem cell marker. When treated with bufalin, the sphere could not get attached to the flask and failed to differentiate, which was indicated by the stable expression of stem cell marker CD133 and OCT-4 in the condition permissive to differentiation. Treatment of bufalin also suppressed the single cells isolated from the sphere to form sphere again in the nonadhesive culture system, and a decreased expression of proliferation marker Ki67 was also detected in these cells. Sphere-formed and chemoresistant colon xenograft tumors in immunodeficient mice could enrich cancer stem cell population. Bufalin could inhibit proliferation and differentiation of CSCs.

Morusin inhibits human cervical cancer stem cell growth and migration through attenuation of NF-κB activity and apoptosis induction

Cancer stem cells (CSCs) are believed to be responsible for tumor metastasis, recurrence, and high mortality of cancer patients due to their high tumorigenicity resistance to chemo-radiotherapy. Morusin possesses anti-cancer activity through attenuation of NF-κB activity, which is up-regulated in cancer stem cells. The purpose of this study is to confirm the growth and migration inhibition effect of morusin on human cervical CSCs, and to clarify its partial mechanism of activity. Human cervical CSCs were enriched using non-adhesive culture system. Their stemness characteristics were identified with tumor sphere formation, self-renewal, toluidine blue staining, migration assays, RT-PCR analysis, and immunofluorescence staining of putative stem cell markers, Oct4, SOX2, and ALDH1; the epithelial-to-mesenchymal (EMT) transition markers and relevant transcription factors were evaluated with Western blotting. The growth and migration inhibition effects of morusin on human cervical CSCs were tested by cell proliferation, tumor sphere formation, and transwell assay; apoptotic death of human cervical CSCs in response to morusin was measured with DAPI staining, apoptotic DNA fragmentation; NF-κBp65, Bcl-2, Bax, and caspase-3 protein expressions were detected through Western blotting. Under this non-adhesive culture system, typical tumor spheres appeared within 5-7days, the tumor sphere formation, self-renewal, and cell migration, expressions of putative stem cell markers, EMT markers, and relevant transcription factors of the tumor sphere cells were increased significantly. After morusin treatment, the proliferation, tumor sphere formation, and migration of human cervical CSCs were decreased significantly, DAPI-stained apoptotic cells increased, apoptotic DNA fragmentations formed evidently; the expression levels of NF-κBp65 and Bcl-2 decreased significantly, Bax, and caspase-3 increased significantly in a dose-dependent manner. Using the non-adhesive culture system, human cervical CSCs were enriched and expanded. Morusin has the potential to target and kill CSCs, and can inhibit human cervical growth and migration through NF-κB attenuation mediated apoptosis induction.

Quercetin Suppresses Drug-Resistant Spheres via the p38 MAPK–Hsp27 Apoptotic Pathway in Oral Cancer Cells

BackgroundTreatment failure in oral squamous cell carcinoma (OSCC) leading to local recurrence(s) and metastases is mainly due to drug resistance. Cancer stem cells (CSCs) are thought be responsible for the development of drug resistance. However, the correlations between CSCs, drug resistance, and new strategy against drug resistance in OSCC remain elusive.MethodsA drug-resistant sphere (DRSP) model was generated by using a nonadhesive culture system to induce drug-resistant cells from SCC25 oral cancer cells. A comparative analysis was performed between the parent control cells and DRSPs with a related treatment strategy focusing on the expression of epithelial–mesenchymal transition (EMT)-associated markers, drug-resistance-related genes, and CSC properties in vitro, as well as tumorigenicity and the regimen for tumor regression in vivo.ResultsOur data show the presence of a phenomenon of EMT with gradual cellular transition from an epithelioid to mesenchymal-like spheroid morphology during induction of drug resistance. The characterization of DRSPs revealed the upregulation of the drug-resistance-related genes ABCG2 and MDR-1 and of CSC-representative markers, suggesting that DRSPs have greater resistance to cisplatin (Cis) and stronger CSC properties compared with the control. Moreover, overexpression of phosphorylated heat-shock protein 27 (p-Hsp27) via the activation of p38 MAPK signaling was observed in DRSPs. Knockdown of Hsp27 decreased Cis resistance and induced apoptosis in DRSPs. Furthermore, an inhibitor of Hsp27, quercetin (Qu), suppressed p-Hsp27 expression, with alterations of the EMT signature, leading to the promotion of apoptosis in DRSPs. A xenographic study also confirmed the increase of tumorigenicity in DRSPs. The combination of Qu and Cis can reduce tumor growth and decrease drug resistance in OSCC.ConclusionsThe p38 MAPK–Hsp27 axis plays an important role in CSCs-mediated drug resistance in OSCC. Targeting this axis using Qu combined with Cis may be a treatment strategy to improve prognosis in patients with OSCC.

Nonadhesive Culture System as a Model of Rapid Sphere Formation with Cancer Stem Cell Properties

BackgroundCancer stem cells (CSCs) play an important role in tumor initiation, progression, and metastasis and are responsible for high therapeutic failure rates. Identification and characterization of CSC are crucial for facilitating the monitoring, therapy, or prevention of cancer. Great efforts have been paid to develop a more effective methodology. Nevertheless, the ideal model for CSC research is still evolving. In this study, we created a nonadhesive culture system to enrich CSCs from human oral squamous cell carcinoma cell lines with sphere formation and to characterize their CSC properties further.MethodsA nonadhesive culture system was designed to generate spheres from the SAS and OECM-1 cell lines. A subsequent investigation of their CSC properties, including stemness, self-renewal, and chemo- and radioresistance in vitro, as well as tumor initiation capacity in vivo, was also performed.ResultsSpheres were formed cost-effectively and time-efficiently within 5 to 7 days. Moreover, we proved that these spheres expressed putative stem cell markers and exhibited chemoradiotherapeutic resistance, in addition to tumor-initiating and self-renewal capabilities.ConclusionsUsing this nonadhesive culture system, we successfully established a rapid and cost-effective model that exhibits the characteristics of CSCs and can be used in cancer research.

Monocytes secrete interleukin-6 when co-cultured in vitro with benign or malignant autologous fragment spheroids from squamous cell carcinoma patients.

Biopsies from tumour and benign mucosa were removed from patients with head and neck squamous-cell carcinoma (HNSCC), chopped into cubes and transferred to a nonadhesive culture system where in vitro fragment (F)-spheroids were established. The F-spheroids stabilized within 14 days of culture in vitro with epithelial cells and fibroblasts on the surface. F-spheroids were co-cultured with freshly isolated autologous monocytes. The monocytes of 10 of 11 patients secreted interleukin (IL)-6 at a level similar to that of the average monocyte endotoxin-stimulated response. Secreted IL-1beta or tumour necrosis factor-alpha (TNF-alpha) levels greater than 0.1 times the endotoxin-stimulated secretion were determined in one and two of the 11 co-culture experiments, respectively. This different monocyte response to F-spheroids compared with endotoxin stimulation was also present at the mRNA expression level. HNSCC monocytes secreted no IL-6 after co-culture with autologous fibroblasts. When monocytes and F-spheroids were cultured separated by a semipermeable membrane, the IL-6 supernatant level was only approximately 25% of that observed during co-culture with direct contact. F-spheroids secreted only trace amounts of IL-6. In conclusion, monocytes of HNSCC patients generally secrete IL-6, but not IL-1beta or TNF-alpha, after stimulation with epithelial-associated components of F-spheroids upon direct contact and in part by a soluble substance.