salinomycin and Carcinoma--Squamous-Cell

The antibiotic drug salinomycin has been reported to mediate cancer cell-specific cytotoxicity, especially regarding cancer stem cells. Since salinomycin has also been reported to arrest cancer cells in the G2 phase, it may have possible radiosensitizing effects. Radiotherapy is a common therapeutic strategy for head and neck squamous cell carcinoma (HNSCC). The aim of the present study was to evaluate a possible influence of salinomycin on the radiosensitivity of the HNSCC cell line HLaC-78 in vitro. HLaC-78 cells were incubated with 5 µM salinomycin or control medium for 24 h and then received 5-Gy irradiation. Subsequently, analysis of cell viability, apoptosis, necrosis and motility through an MTT and a colony formation assay, as well as an Annexin V/propidium-iodide test, a consecutive cell count for four days and a scratch assay were conducted. Additionally, interleukin-8 secretion was assessed using ELISA, due to its role in tumor progression and angiogenesis. Combined treatment with salinomycin and radiation revealed a significantly higher reduction of tumor cell viability, proliferation, motility and secretory capacity compared to cells receiving only one of the treatments alone. Therefore, it is postulated that radiation and salinomycin are an effective combination therapy against HNSCC, a hypothesis which warrants further investigation in cell lines, as well as in an animal model.

Topics: Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Combined Modality Therapy; Head and Neck Neoplasms; Humans; Neoplastic Stem Cells; Pyrans; Radiation Tolerance; Squamous Cell Carcinoma of Head and Neck

To target both head and neck squamous cell carcinoma (HNSCC) cells and cancer stem cells (CSCs) by salinomycin-loaded DSPE-PEG-MTX (synthesized using DSPE-PEG2000-NH2 and methotrexate) nanomicelles (M-SAL-MTX).. The characterization, antitumor activity and mechanism of M-SAL-MTX were evaluated.. M-SAL-MTX showed enhanced inhibitory effect toward both HNSCC CSCs and non-CSCs compared with a single treatment of methotrexate and salinomycin. In nude mice-bearing HNSCC xenografts, M-SAL-MTX suppressed tumor growth more effectively than other controls including combination of methotrexate and salinomycin. Therefore, M-SAL-MTX may provide a strategy for treating HNSCC by targeting both HNSCC CSCs and HNSCC cells.

Topics: Animals; Anti-Bacterial Agents; Antimetabolites, Antineoplastic; Carcinoma, Squamous Cell; Cell Line, Tumor; Drug Carriers; Drug Delivery Systems; Head and Neck Neoplasms; Humans; Male; Methotrexate; Mice, Inbred BALB C; Mice, Nude; Micelles; Neoplastic Stem Cells; Phosphatidylethanolamines; Polyethylene Glycols; Pyrans; Squamous Cell Carcinoma of Head and Neck

Surgery, radiation, chemotherapy or a combinations of these are all accepted modalities for the treatment of head and neck squamous cell carcinoma (HNSCC). Despite this, 40‑60% of patients suffering from HNSCC develop loco‑regional failure and/or distant metastases. Salinomycin has been demonstrated to be >100‑fold more effective than paclitaxel at causing cancer stem cell death, therefore, it may offer an important improvement in cancer therapy. However, the toxicity of salinomycin is of concern. A possible solution may be the administration of additive drugs, which reduce the toxicity. By inhibiting the mitochondrial Na+/Ca2+ exchanger using the benzodiazepine derivate, CGP37157 (CGP), a significant reduction in salinomycin neuronal toxicity has been observed. This raises the question of whether CGP also inhibits the tumor toxicity of salinomycin. In the present study, the FaDu and HLaC79 C1 HNSCC cell lines were treated with salinomycin with or without CGP. Comparative viability assessments were performed using microscopy, a fluorescein diacetate assay, an MTT assay, a clonogenic assay and annexin V‑propidium iodide staining. The expression levels of MDR‑1 were monitored using reverse transcription‑quantitative polymerase chain reaction. Salinomycin alone, and in combination with CGP, achieved a significant attenuation of cell viability and increased apoptosis in a dose‑dependent manner. However, the tumor toxicity of salinomycin was not inhibited by CGP. The HLaC79 C1 cells were more sensitive to salinomycin, compared with the FaDu cells, with this sensitivity being due to high expression levels of MDR‑1 by the HLaC79 C1 cells. In conclusion, CGP did not counteract the tumor toxicity of salinomycin in vitro and may be a promising drug in future anticancer therapy. The results of the present study encourages further investigation of the toxicological aspects of salinomycin, particularly in human cells and animal models.

Topics: Antineoplastic Agents; Apoptosis; ATP Binding Cassette Transporter, Subfamily B; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Shape; Clonazepam; Drug Screening Assays, Antitumor; Gene Expression; Head and Neck Neoplasms; Humans; Pyrans; Thiazepines

Cancer stem cells (CSC) are believed to play a crucial role in cancer recurrence due to their resistance to conventional chemotherapy and capacity for self-renewal. Recent studies have reported that salinomycin, a livestock antibiotic, selectively targets breast cancer stem cells 100-fold more effectively than paclitaxel. In our study we sought to determine the effects of salinomycin on head and neck squamous cell carcinoma (HNSCC) stem cells.. MTS and TUNEL assays were used to study cell proliferation and apoptosis as a function of salinomycin exposure in JLO-1, a putative HNSCC stem cell culture. MTS and trypan blue dye exclusion assays were performed to investigate potential drug interactions between salinomycin and cisplatin or paclitaxel. Stem cell-like phenotype was measured by mRNA expression of stem cell markers, sphere-forming capacity, and matrigel invasion assays. Immunoblotting was also used to determine expression of epithelial-mesenchymal transition (EMT) markers and Akt phosphorylation. Arrays by Illumina, Inc. were used to profile microRNA expression as a function of salinomycin dose.. In putative HNSCC stem cells, salinomycin was found to significantly inhibit cell viability, induce a 71.5% increase in levels of apoptosis, elevate the Bax/Bcl-2 ratio, and work synergistically with cisplatin and paclitaxel in inducing cell death. It was observed that salinomycin significantly inhibited sphere forming-capability and repressed the expression of CD44 and BMI-1 by 3.2-fold and 6.2-fold, respectively. Furthermore, salinomycin reduced invasion of HNSCC stem cells by 2.1 fold. Contrary to expectations, salinomycin induced the expression of EMT markers Snail, vimentin, and Zeb-1, decreased expression of E-cadherin, and also induced phosphorylation of Akt and its downstream targets GSK3-β and mTOR.. These results demonstrate that in HNSCC cancer stem cells, salinomycin can cause cell death and decrease stem cell properties despite activation of both EMT and Akt.

Topics: Apoptosis; bcl-2-Associated X Protein; Carcinoma, Squamous Cell; Cell Death; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cisplatin; Drug Interactions; Enzyme Activation; Epithelial-Mesenchymal Transition; Head and Neck Neoplasms; Humans; Hyaluronan Receptors; MicroRNAs; Mitogen-Activated Protein Kinase 7; Neoplastic Stem Cells; Paclitaxel; Phosphorylation; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; Pyrans; RNA, Messenger; Squamous Cell Carcinoma of Head and Neck

Curative eradication of all cells within carcinomas is seldom achievable with chemotherapy alone. This limitation may be partially attributable to tumor cell subpopulations with intrinsic resistance to current drugs. Within squamous cell carcinoma (SCC) cell lines, we previously characterized a subpopulation of mesenchymal-like cells displaying phenotypic plasticity and increased resistance to both cytotoxic and targeted agents. These mesenchymal-like (Ecad-lo) cells are separable from epithelial-like (Ecad-hi) cells based on loss of surface E-cadherin and expression of vimentin. Despite their long-term plasticity, both Ecad-lo and Ecad-hi subsets in short-term culture maintained nearly uniform phenotypes after purification. This stability allowed testing of segregated subpopulations for relative sensitivity to the cytotoxic agent cisplatin in comparison to salinomycin, a compound with reported activity against CD44(+)CD24(-) stem-like cells in breast carcinomas. Salinomycin showed comparable efficacy against both Ecad-hi and Ecad-lo cells in contrast to cisplatin, which selectively depleted Ecad-hi cells. An in vivo correlate of these mesenchymal-like Ecad-lo cells was identified by immunohistochemical detection of vimentin-positive malignant subsets across a part of direct tumor xenografts (DTXs) of advanced stage SCC patient samples. Cisplatin treatment of mice with established DTXs caused enrichment of vimentin-positive malignant cells in residual tumors, but salinomycin depleted the same subpopulation. These results demonstrate that mesenchymal-like SCC cells, which resist current chemotherapies, respond to a treatment strategy developed against a stem-like subset in breast carcinoma. Further, they provide evidence of mesenchymal-like subsets being well-represented across advanced stage SCCs, suggesting that intrinsic drug resistance in this subpopulation has high clinical relevance.

Topics: Animals; Breast Neoplasms; Carcinoma, Squamous Cell; Cell Culture Techniques; Cell Line, Tumor; Cisplatin; Drug Resistance, Neoplasm; Humans; Mesenchymal Stem Cells; Mice; Pyrans; Transplantation, Heterologous