Comparison of chemosensitivity tests: clonogenic assay versus MTT assay

Inhibition of IκB Kinase Is a Potential Therapeutic Strategy to Circumvent Resistance to Epidermal Growth Factor Receptor Inhibition in Triple-Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) remains as an intractable malignancy with limited therapeutic targets. High expression of epidermal growth factor receptor (EGFR) has been associated with a poor prognosis of TNBC; however, EGFR targeting has failed with unfavorable clinical outcomes. Here, we performed a combinatorial screening of fifty-five protein kinase inhibitors with the EGFR inhibitor gefitinib in the TNBC cell line MDA-MB-231 and identified the IκB kinase (IKK) inhibitor IKK16 as a sensitizer of gefitinib. Cell viability and clonogenic survival assays were performed to evaluate the antiproliferative effects of the gefitinib and IKK16 (Gefitinib + IKK16) combination in TNBC cell lines. Western blot analyses were also performed to reveal the potential mode of action of this combination. In addition, next-generation sequencing (NGS) analysis was performed in Gefitinib+IKK16-treated cells. The Gefitinib+IKK16 treatment synergistically reduced cell viability and colony formation of TNBC cell lines such as HS578T, MDA-MB-231, and MDA-MB-468. This combination downregulated p-STAT3, p-AKT, p-mTOR, p-GSK3β, and p-RPS6. In addition, p-NF-κB and the total NF-κB were also regulated by this combination. Furthermore, NGS analysis revealed that NF-κB/RELA targets including CCL2, CXCL8, EDN1, IL-1β, IL-6, and SERPINE1 were further reduced and several potential tumor suppressors, such as FABP3, FADS2, FDFT1, SEMA6A, and PCK2, were synergistically induced by the Gefitinib-+IKK16 treatment. Taken together, we identified the IKK/NF-κB pathway as a potential target in combination of EGFR inhibition for treating TNBC.

CeCILE - An Artificial Intelligence Based Cell-Detection for the Evaluation of Radiation Effects in Eucaryotic Cells

The fundamental basis in the development of novel radiotherapy methods is in-vitro cellular studies. To assess different endpoints of cellular reactions to irradiation like proliferation, cell cycle arrest, and cell death, several assays are used in radiobiological research as standard methods. For example, colony forming assay investigates cell survival and Caspase3/7-Sytox assay cell death. The major limitation of these assays is the analysis at a fixed timepoint after irradiation. Thus, not much is known about the reactions before or after the assay is performed. Additionally, these assays need special treatments, which influence cell behavior and health. In this study, a completely new method is proposed to tackle these challenges: A deep-learning algorithm called CeCILE (Cell Classification and In-vitro Lifecycle Evaluation), which is used to detect and analyze cells on videos obtained from phase-contrast microscopy. With this method, we can observe and analyze the behavior and the health conditions of single cells over several days after treatment, up to a sample size of 100 cells per image frame. To train CeCILE, we built a dataset by labeling cells on microscopic images and assign class labels to each cell, which define the cell states in the cell cycle. After successful training of CeCILE, we irradiated CHO-K1 cells with 4 Gy protons, imaged them for 2 days by a microscope equipped with a live-cell-imaging set-up, and analyzed the videos by CeCILE and by hand. From analysis, we gained information about cell numbers, cell divisions, and cell deaths over time. We could show that similar results were achieved in the first proof of principle compared with colony forming and Caspase3/7-Sytox assays in this experiment. Therefore, CeCILE has the potential to assess the same endpoints as state-of-the-art assays but gives extra information about the evolution of cell numbers, cell state, and cell cycle. Additionally, CeCILE will be extended to track individual cells and their descendants throughout the whole video to follow the behavior of each cell and the progeny after irradiation. This tracking method is capable to put radiobiologic research to the next level to obtain a better understanding of the cellular reactions to radiation.

Fluoxetine as an antidepressant medicine improves the effects of ionizing radiation for the treatment of glioma

Radiotherapy is a cancer treatment protocol which delivers high dose of ionizing radiation (IR) to tumor. Tumor resistance and side effects induced by IR still are the major challenges in radiotherapy. The purpose of this study was to evaluate the synergistic killing effect of fluoxetine (FL) with IR on glioma cancer cell (U-87 MG), as well as radioprotective effect of FL against cellular toxicity induced by IR on non-malignant human fibroblast cell (HFFF2). Firstly, the inhibitory effects of FL on cell proliferations were evaluated in U-87 MG and HFFF2 cells. The clonogenic and MTT assays were used to evaluate the radiosensitivity and radioprotective effects of FL on cancer and non-malignant cells. The frequencies of apoptotic cells were evaluated by flow cytometry on both cancer and normal cells. Results showed that FL exhibited anti-cancer effect on glioma cells, while cellular toxicity was low in HFFF2 cells treated with FL. FL decreased the viable colonies and enhanced apoptotic cells when U-87 cells were treated with FL prior irradiation. For comparison, FL exhibited radioprotective effect through increasing cellular proliferation rate and reducing apoptosis in HFFF2 cells against IR. The results showed that FL enhanced the IR-induced glioma cancer cell death and apoptosis, whereas it exhibited a radioprotective effect on normal fibroblast cells suggesting that FL administration may improve glioma radiotherapy.

Induction of apoptosis in human cervical carcinoma HeLa cells by active compounds from Hypericum ascyron L

Hypericum ascyron L. (Great St. Johnswort), which belongs to the Hypericaceae family, has been used for the treatment of hematemesis, metrorrhagia, rheumatism, swelling, stomach ache, abscesses, dysentery and irregular menstruation for >2,000 years in China. The aim of the present study was to clarify the anticancer activity compounds from H. ascyron L. and the underlying molecular mechanism. Anticancer activity of H. ascyron L. extract was evaluated using an MTT assay. To confirm the anticancer mechanism of activity compounds, Hoechst 33258, Annexin V-fluorescein isothiocyanate/propidium iodide, 2',7'-dichlorodihydrofluorescein diacetate, rhodamine 123 staining and caspase-3 activity analysis were performed. The results demonstrated that the anti-proliferative action of the mixture of kaempferol 3-O-β-(2″-acetyl) galactopyranoside (K) and quercetin (Q) (molar ratio, 1:1) was significantly increased compared with either of these two compounds separately, and the active fraction of the H. ascyron L. extract |(HALE). HALE, indicating that the anti-proliferative function of H. ascyron L. may be a synergic effect of K and Q. Furthermore, the inhibitory effect of KQ on the growth of HeLa cells was mediated by the induction of apoptosis. To the best of our knowledge, the present study is the first to identify that KQ exhibits significant anti-proliferation activity on HeLa cells via the apoptotic pathway, and is also the first to evaluate the anticancer potential of H. ascyron L. The results of the present study may provide a rational base for the use of H. ascyron L. in the clinic, and shed light on the development of novel anticancer drugs.

PLGA nanoparticle encapsulation reduces toxicity while retaining the therapeutic efficacy of EtNBS-PDT in vitro

Photodynamic therapy regimens, which use light-activated molecules known as photosensitizers, are highly selective against many malignancies and can bypass certain challenging therapeutic resistance mechanisms. Photosensitizers such as the small cationic molecule EtNBS (5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride) have proven potent against cancer cells that reside within acidic and hypoxic tumour microenvironments. At higher doses, however, these photosensitizers induce "dark toxicity" through light-independent mechanisms. In this study, we evaluated the use of nanoparticle encapsulation to overcome this limitation. Interestingly, encapsulation of the compound within poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA-EtNBS) was found to significantly reduce EtNBS dark toxicity while completely retaining the molecule's cytotoxicity in both normoxic and hypoxic conditions. This dual effect can be attributed to the mechanism of release: EtNBS remains encapsulated until external light irradiation, which stimulates an oxygen-independent, radical-mediated process that degrades the PLGA nanoparticles and releases the molecule. As these PLGA-encapsulated EtNBS nanoparticles are capable of penetrating deeply into the hypoxic and acidic cores of 3D spheroid cultures, they may enable the safe and efficacious treatment of otherwise unresponsive tumour regions.

p38δ MAPK phenotype: an indicator of chemotherapeutic response in oesophageal squamous cell carcinoma

We recently documented p38δ differential expression and function in oesophageal squamous cell carcinoma (OESCC). This study expands upon these findings and investigates whether p38δ status in OESCC can influence response(s) to cytotoxic drugs. The antiproliferative effect of conventional cisplatin and 5-fluorouracil (CF) treatment was compared with the recently reviewed triple regime of cisplatin, 5-fluorouracil and doxorubicin (ACF). p38δ-positive and p38δ-negative cell lines were employed using cell-growth and clonogenic assays. Key regulators of intrinsic and extrinsic apoptotic pathways were measured. Wound-healing assays and a Boyden chamber were used to investigate the effect of drug treatments on cell migration. Functional networks were analysed in terms of changes in MAPK expression. p38δ-negative OESCC is less sensitive to standard CF chemotherapy compared with p38δ-positive cells. However, following ACF treatment p38δ-negative cells showed markedly decreased proliferation and cell migration, and increased apoptosis. ACF induced apoptosis through the extrinsic pathway involving Fas activation, caspase-8 and caspase-3 cleavage and degradation of PARP. Loss of mitochondrial membrane potential (ΔΨm) was observed but downregulation of multidomain proapoptotic proteins, as well as BH3-only proteins, suggests involvement of pathways other than the mitochondrial pathway. Interestingly, induction of p38 and ERK1/2, but not JNK1/2, was observed following ACF treatment. p38δ-negative OESCC is more resistant to traditional CF treatment compared with p38δ-positive OESCC. In light of these results, p38δ phenotyping of tumour tissue may be of considerable value in deciding on an optimal therapeutic strategy for patients with p38δ-negative OESCC.

Upregulation of glycolytic enzymes, mitochondrial dysfunction and increased cytotoxicity in glial cells treated with Alzheimer's disease plasma

Alzheimer's disease (AD) is a neurodegenerative disorder associated with increased oxidative stress and neuroinflammation. Markers of increased protein, lipid and nucleic acid oxidation and reduced activities of antioxidant enzymes have been reported in AD plasma. Amyloid plaques in the AD brain elicit a range of reactive inflammatory responses including complement activation and acute phase reactions, which may also be reflected in plasma. Previous studies have shown that human AD plasma may be cytotoxic to cultured cells. We investigated the effect of pooled plasma (n = 20 each) from healthy controls, individuals with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD) on cultured microglial cells. AD plasma and was found to significantly decrease cell viability and increase glycolytic flux in microglia compared to plasma from healthy controls. This effect was prevented by the heat inactivation of complement. Proteomic methods and isobaric tags (iTRAQ) found the expression level of complement and other acute phase proteins to be altered in MCI and AD plasma and an upregulation of key enzymes involved in the glycolysis pathway in cells exposed to AD plasma. Altered expression levels of acute phase reactants in AD plasma may alter the energy metabolism of glia.

The effect of Msh2 knockdown on toxicity induced by tert-butyl-hydroperoxide, potassium bromate, and hydrogen peroxide in base excision repair proficient and deficient cells

The DNA mismatch repair (MMR) and base excision repair (BER) systems are important determinants of cellular toxicity following exposure to agents that cause oxidative DNA damage. To examine the interactions between these different repair systems, we examined whether toxicity, induced by t-BOOH and KBrO₃, differs in BER proficient (Mpg^+/+, Nth1^+/+) and deficient (Mpg^−/−, Nth1^−/−) mouse embryonic fibroblasts (MEFs) following Msh2 knockdown of between 79 and 88% using an shRNA expression vector. Msh2 knockdown in Nth1^+/+ cells had no effect on t-BOOH and KBrO₃ induced toxicity as assessed by an MTT assay; knockdown in Nth1^−/− cells resulted in increased resistance to t-BOOH and KBrO₃, a result consistent with Nth1 removing oxidised pyrimidines. Msh2 knockdown in Mpg^+/+ cells had no effect on t-BOOH toxicity but increased resistance to KBrO₃; in Mpg^−/− cells, Msh2 knockdown increased cellular sensitivity to KBrO₃ but increased resistance to t-BOOH, suggesting a role for Mpg in removing DNA damage induced by these agents. MSH2 dependent and independent pathways then determine cellular toxicity induced by oxidising agents. A complex interaction between MMR and BER repair systems, that is, exposure dependent, also exists to determine cellular toxicity.

In vitro optimization of EtNBS-PDT against hypoxic tumor environments with a tiered, high-content, 3D model optical screening platform

Hypoxia and acidosis are widely recognized as major contributors to the development of treatment resistant cancer. For patients with disseminated metastatic lesions, such as most women with ovarian cancer (OvCa), the progression to treatment resistant disease is almost always fatal. Numerous therapeutic approaches have been developed to eliminate treatment resistant carcinoma, including novel biologic, chemo, radiation, and photodynamic therapy (PDT) regimens. Recently, PDT using the cationic photosensitizer EtNBS was found to be highly effective against therapeutically unresponsive hypoxic and acidic OvCa cellular populations in vitro. To optimize this treatment regimen, we developed a tiered, high-content, image-based screening approach utilizing a biologically relevant OvCa 3D culture model to investigate a small library of side-chain modified EtNBS derivatives. The uptake, localization, and photocytotoxicity of these compounds on both the cellular and nodular levels were observed to be largely mediated by their respective ethyl side chain chemical alterations. In particular, EtNBS and its hydroxyl-terminated derivative (EtNBS-OH) were found to have similar pharmacological parameters, such as their nodular localization patterns and uptake kinetics. Interestingly, these two molecules were found to induce dramatically different therapeutic outcomes: EtNBS was found to be more effective in killing the hypoxic, nodule core cells with superior selectivity, while EtNBS-OH was observed to trigger widespread structural degradation of nodules. This breakdown of the tumor architecture can improve the therapeutic outcome and is known to synergistically enhance the antitumor effects of front-line chemotherapeutic regimens. These results, which would not have been predicted or observed using traditional monolayer or in vivo animal screening techniques, demonstrate the powerful capabilities of 3D in vitro screening approaches for the selection and optimization of therapeutic agents for the targeted destruction of specific cellular subpopulations.

Quercetin enhances the effects of 5-fluorouracil-mediated growth inhibition and apoptosis of esophageal cancer cells by inhibiting NF-κB

Despite its limited success, 5-fluorouracil (5-FU) remains the primary chemotherapy agent for the treatment of esophageal cancer. Quercetin has been demonstrated to inhibit the growth of transformed cells. The present study was conducted to examine whether quercetin combined with conventional chemotherapeutic agents would improve the therapeutic strategy for esophageal cancer. In this study, an MTT assay was used to determine the effects of quercetin on the proliferation of EC9706 and Eca109 cells. Annexin V-FITC/propidium iodide (PI)-stained fluorescence-activated cell sorter (FACS) analysis was used to detect the apoptotic fraction of treated cells, and western blot analysis was used to examine the protein levels. The results of our study demonstrated that quercetin in combination with 5-FU significantly inhibited growth (P<0.05) and stimulated apoptosis (P<0.005) in EC9706 and Eca109 esophageal cancer cells compared with quercetin or 5-FU alone. These changes were associated with the decreased expression of a phosphorylated inhibitory molecule of NF-κB (pIκBα), which was activated by exposure to 5-FU alone. We suggest that inclusion of quercetin to the conventional chemotherapeutic agent 5-FU may be an effective therapeutic strategy for esophageal cancer.

FSH stimulates lipid biosynthesis in chicken adipose tissue by upregulating the expression of its receptor FSHR

Transcripts and protein for follicle-stimulating hormone receptor (FSHR) were demonstrated in abdominal adipose tissue of female chickens. There was no expression of the Fsh gene, but FSH and FSHR colocalized, suggesting that FSH was receptor bound. Partial correlations indicted that changes in abdominal fat (AF) content were most directly correlated with Fshr mRNA expression, and the latter was directly correlated with tissue FSH content. These relationships were consistent with FSH inducing Fshr mRNA expression and with the finding that FSH influenced the accumulation of AF in chickens, a novel role for the hormone. Chicken preadipocytes responded linearly to doubling concentrations of FSH in Fshr mRNA expression and quantities of FSHR and lipid, without discernable effect on proliferation. Cells exposed to FSH more rapidly acquired adipocyte morphology. Treatment of young chickens with chicken FSH (4 mIU/day, subcutaneous, days 7-13) did not significantly decrease live weight but increased AF weight by 54.61%, AF as a percentage of live weight by 55.45%, and FSHR transcripts in AF by 222.15% (2 h after injection). In cells stimulated by FSH, genes related to lipid metabolism, including Rdh10, Dci, RarB, Lpl, Acsl3, and Dgat2, were expressed differentially, compared with no FSH. Several pathways of retinal and fatty acid metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling changed. In conclusion, FSH stimulates lipid biosynthesis by upregulating Fshr mRNA expression in abdominal adipose tissue of chickens. Several genes involved in fatty acid and retinal metabolism and the PPAR signaling pathway mediate this novel function of FSH.

Synthesis, photophysical, electrochemical, tumor-imaging, and phototherapeutic properties of purpurinimide-N-substituted cyanine dyes joined with variable lengths of linkers

Purpurinimide methyl esters, bearing variable lengths of N-substitutions, were conjugated individually to a cyanine dye with a carboxylic acid functionality. The results obtained from in vitro and in vivo studies showed a significant impact of the linkers joining the phototherapeutic and fluorescence imaging moieties. The photosensitizer-fluorophore conjugate with a PEG linker showed the highest uptake in the liver, whereas the conjugate linked with two carbon units showed excellent tumor-imaging and PDT efficacy at 24 h postinjection. Whole body imaging and biodistribution studies at variable time points portrayed enhanced fluorescent uptake of the conjugates in the tumor compared to that in the skin. Interestingly, the conjugate with the shortest linker and the one joining with two carbon units showed faster clearance from normal organs, e.g., the liver, kidney, spleen, and lung, compared to that in tumors. Both imaging and PDT efficacy of the conjugates were performed in BALB/c mice bearing Colon26 tumors. Compared to the others, the short linker conjugate showed poor tumor fluorescent properties and as a corollary does not exhibit the dual functionality of the photosensitizer-fluorophore conjugate. For this reason, it was not evaluated for in vivo PDT efficacy. However, in Colon26 tumor cells (in vitro), the short linker was highly effective. Among the conjugates with variable linkers, the rate of energy transfer from the purpurinimide moiety to the cyanine moiety increased with deceasing linker length, as examined by femtosecond laser flash photolysis measurements. No electron transfer from the purpurinimide moiety to the singlet excited state of the cyanine moiety or from the singlet excited state of the cyanine moiety to the purpurinimide moiety occurred as indicated by a comparison of transient absorption spectra with spectra of the one-electron oxidized and one-electron reduced species of the conjugate obtained by spectroelectrochemical measurements.

Differences in estimates of cisplatin-induced cell kill in vitro between colorimetric and cell count/colony assays

The aim of this study was to evaluate some bioassays that are different in principle: cell counting, colony forming assay, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT), sulforhodamine B (SRB), crystal violet, and alamarBlue, with respect to their ability to measure cisplatin-induced cell death of in vitro-cultivated squamous cell carcinoma of the head and neck (SCCHN). Cisplatin was applied in concentrations of 1.0, 5.0, 10.0, 50.0, and 100 microM. The cells were incubated for 1 h, and the cell survival was measured 5 d after treatment. We found the colorimetric assays and cell counting to be comparable. The colony forming assay indicated a higher degree of cell kill compared with the other techniques. Measurement of cell survival after treatment with cisplatin can be done by use of any of the above tested assays. However, the majority of SCCHN cell lines available do not form colonies easily, or at all. Therefore, comparing the chemosensitivity between such cell lines is limited to alternative assays. In this respect, any of the tested colorimetric assays can be used. However, they seem to underestimate cell kill. Cell counting is also an alternative. This technique, however, is time consuming and operator dependent, as in the case of manual counting, or relatively expensive when counting is performed electronically, compared with the colorimetric assays.

Naturally occurring resistance of bone marrow mononuclear and metastatic cancer cells to anticancer agents

Numerous cancer patients fail standard chemotherapy or develop resistance to chemotherapy during the course of treatment. The purpose of this study is to elucidate the overall response of cells obtained from cancer patients and from normal individuals to chemotherapeutic agents. We analysed the chemosensitivity of cancer cells derived from bone marrow and from pleural effusions or ascites fluids from patients with different cancers. Chemosensitivity to doxorubicin, cisplatin and paclitaxel was determined using the MTT assay. We also determined the response of bone marrow mononuclear (BMMN) cells. There was a wide range of responses to chemotherapy drugs in samples from different individuals. This was observed in cells derived from bone marrow and from ascites or pleural fluids. Large variations were also observed among morphologically normal BMMN cells and metastatic cancer cells from chemo-naïve patients. Cancer cells can easily be collected from ascites or pleural fluids and reliably assayed for chemosensitivity. We describe here that inherent chemoresistance may be a reason for the lack of response to chemotherapy in some patients. We discuss the potential of using the determination of natural resistance to dictate the drugs to be employed for treatment.