Cell Death In Carcinoma Research Articles

STAT3 is a potential therapeutic target in cervical cancer (257)

<b>Objectives:</b> STAT3 is known to be hyperactivated in most human cancers and is associated with poor prognoses. The STAT3 activation pathway within human papillomavirus (HPV)-positive cervical cancer cells is known to be essential for cervical cancer cell proliferation and survival. However, whether STAT3 activity is elevated in cervical cancer patient tumors remains to be determined. We sought to assess whether activated STAT3 (p-STAT3) was more highly expressed in cervical squamous cell carcinoma tissue microarrays compared to benign adjacent cervix tissue. We also assessed the ability of a small molecule inhibitor of STAT3 that has been used in the clinic to attenuate the STAT3 activation pathway and induce tumor cell death of HPV-associated human squamous cell carcinoma cells <i>in vitro</i>. <b>Methods:</b> Tumor microarrays from 12 patients with cervical squamous cell carcinoma with adjacent, benign cervix tissue were first probed with an anti-p-STAT3 antibody and detected with a fluorophore-conjugated secondary antibody for p-STAT3. Confocal imaging of immunofluorescence was performed, and fluorescence quantification was performed by ZEN 2.3 lite software and plotted in GraphPad Prism 8 software. The CaSki HPV16 infected cervical squamous cell carcinoma cell line was used for <i>in vitro</i> experiments. CaSki cells were treated with BBI608 (a small molecule inhibitor of STAT3) and assessed for changes in the STAT3 activation axis using Western Blot. Cell viability was analyzed using CellTiter-Glo® Luminescent Cell Viability Assay. <b>Results:</b> Quantification of p-STAT3 immunofluorescence from confocal imaging showed significantly higher expression of p-STAT3 in cervical squamous cell carcinoma tissue microarrays compared to adjacent, benign cervix tissue with mean expression levels of 37.7 relative units (RU) vs 29.1 RU, respectively (p=0.006). On Western Blot, BBI608 (3uM and 4uM) was found to attenuate the STAT3 activation axis in a dose-dependent fashion, including a significant decrease in p-JAK1 and p-STAT3 protein expressions. Furthermore, the protein expression of <i>HIF1A</i>, a known downstream STAT3 target gene and associated with poor survival and treatment resistance in cervical cancer, was also decreased by BBI608 (3uM and 4uM) in a similar fashion. On analysis of cell viability, BBI608 was found capable of inducing cell death in CaSki cells with an IC50 of 2.6uM after a 48-hour incubation period. <b>Conclusions:</b> The STAT3 activation pathway is a logical and promising target for therapeutic intervention in cervical cancer. On review of HPV-associated cervical cancer tumor arrays, we found a significantly higher expression of pSTAT3 in cervical tumor cells and tumor-infiltrating lymphocytes compared to adjacent, benign tissue. Furthermore, we found that BBI608 was able to attenuate the STAT3 activation axis and induce cell death in the CaSki cervical squamous cell carcinoma cell line.Fig. 1

Activation of nano-photosensitizers by Y-90 microspheres to enhance oxidative stress and cell death in hepatocellular carcinoma

While radioembolization with yttrium-90 (Y-90) microspheres is a promising treatment for hepatocellular carcinoma (HCC), lower responses in advanced and high-grade tumors present an urgent need to augment its tumoricidal efficacy. The purpose of this study was to determine whether clinically used Y-90 microspheres activate light-responsive nano-photosensitizers to enhance hepatocellular carcinoma (HCC) cell oxidative stress and cytotoxicity over Y-90 alone in vitro. Singlet oxygen and hydroxyl radical production was enhanced when Y-90 microspheres were in the presence of several nano-photosensitizers compared to either alone in cell-free conditions. Both the SNU-387 and HepG2 human HCC cells demonstrated significantly lower viability when treated with low activity Y-90 microspheres (0.1–0.2 MBq/0.2 mL) and a nano-photosensitizer consisting of both titanium dioxide (TiO2) and titanocene (TC) labelled with transferrin (TiO2-Tf-TC) compared to Y-90 microspheres alone or untreated cells. Cellular oxidative stress and cell death demonstrated a linear dependence on Y-90 at higher activities (up to 0.75 MBq/0.2 mL), but was significantly more accentuated in the presence of increasing TiO2-Tf-TC concentrations in the poorly differentiated SNU-387 HCC cell line (p < 0.0001 and p = 0.0002 respectively) but not the well-differentiated HepG2 cell line. Addition of TiO2-Tf-TC to normal human hepatocyte THLE-2 cells did not increase cellular oxidative stress or cell death in the presence of Y-90. The enhanced tumoricidal activity of nano-photosensitizers with Y-90 microspheres is a potentially promising adjunctive treatment strategy for certain patient subsets. Applications in clinically relevant in vivo HCC models are underway.

Targeting stearoyl-coa desaturase enhances radiation induced ferroptosis and immunogenic cell death in esophageal squamous cell carcinoma

ABSTRACT Overcoming resistance to radiation is a major challenge in cancer treatment. Stearoyl-coa desaturase (SCD1) is the enzyme responsible for oleic acid (OA) and palmitoleic acid (POA) formation. Here, we provided evidence that targeting SCD1 was capable of inducing ferroptosis and immunogenic cell death (ICD), thereby improving the radiation sensitivity of esophageal squamous cell carcinoma (ESCC). ESCC cell lines with high SCD1 expression were treated with MF-438 (SCD1 inhibitor) to determine cell viability. Colony formation assay was performed to evaluate the radiation sensitization of SCD1 inhibitor. Tumor cell ferroptosis and ICD was analyzed in MF-438, radiation therapy (RT) and the combination treatment group. The potential molecular mechanisms underlying MF-438 as a novel radiation sensitizer in ESCC were explored. We concluded by assessing SCD1 as a prognostic factor in ESCC. MF-438 exhibited antitumor activity in ESCC cells. Our outcomes revealed significant improvement of radiation sensitivity by MF-438. Moreover, the combination treatment enhanced tumor cell ferroptosis and ICD. Further analyses revealed SCD1 conferred radiation resistance via alleviating ferroptosis in tumor cells; targeting SCD1 inhibited the biosynthesis of OA and POA, and improved radiation induced ferroptosis in ESCC cells. Clinical analysis indicated high expression of SCD1 was associated with unfavorable survival in patients of ESCC. In summary, our results demonstrated that MF-438 acted as a ferroptosis inducer. Targeting SCD1 conferred the immunogenicity of ferroptotic cancer cells and increased the effectiveness of RT in ESCC. SCD1 could be considered as a useful prognostic indicator of survival in ESCC.

Diluted Lycopodium Induced Cell Death and Clinical Improvement in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common cancer with high incidence rate, and 5-year survival rate in HCC is less than 20%. Thus, in search of newer anticancer agents effective in HCC, we have explored possible usefulness of an alternative medicine Lycopodium against the human liver cancer cell line, HepG2 along with its clinical efficacy. The HepG2 cell line was challenged with Lycopodium 6C (diluted Lycopodium &lt;1pg /mL available as alternative medicine) along with vehicle alcohol control in 24 hours. The cytopathic effect and viability test with methylene blue stain were observed. The cells were harvested for total RNA extraction, and gene expression levels of targeted cytokines -Interferon gamma (IFN γ); Interleukins - IL-6, IL-8, IL-10, IL-1β, Transforming Growth Factor- TGF-β1, TGF-β3 and Tumor Necrosis Factor alpha (TNF-α) by RT-PCR were studied. DNA fragmentation assay and cell viability assay by MTT method were also tested. After ethical permission we applied this medicine as adjunct therapy to observe any beneficial role of the medicine. Statistically significant changes of IL-10, IL-1β and TGF-β3 were observed after challenge with Lycopodium 6C. The IL-10 gene expression in malignant cells was significantly reduced with Lycopodium 6C; however, the expression is more with vehicle alcohol compared to normal control set. Thus, the medicine could decrease the excessive IL-10 gene expression to a moderate level. IL-1β and TGF-β3 gene up-regulation by the vehicle alcohol were also mitigated by the medicine Lycopodium 6C. Mild DNA fragmentation was also seen in cancer cells after challenge with the medicine. Two cases suffering from hepatocellular carcinoma showed much clinical improvement after therapy with this medicine. Lycopodium 6C may act as a supporting alternative medication for treating HCC.

Targeted inhibition of STAT3 induces immunogenic cell death of hepatocellular carcinoma cells via glycolysis.

In hepatocellular carcinoma (HCC), the signal transducer and activator of transcription 3 (STAT3) is present in an overactive state that is closely related to tumour development and immune escape. STAT3 inhibition reshapes the tumour immune microenvironment, but the underlying mechanisms have not been fully clarified. We found that STAT3 inhibition could induce immunogenic cell death (ICD) of HCC cells via translocation of the “eat me” molecule calreticulin to the cell surface and a significant reduction in the expression of the “don’t eat me” molecule leucocyte surface antigen CD47. STAT3 inhibition promoted dendritic cell (DC) activation and enhanced the recognition and phagocytosis of HCC cells by macrophages. Furthermore, STAT3 inhibition prevented the expression of key glycolytic enzymes, facilitating the induction of ICD in HCC. Interestingly, STAT3 directly regulated the transcription of CD47 and solute carrier family 2 member 1 (SLC2A1; also known as GLUT1). In subcutaneous and orthotopic transplantation mouse tumour models, the STAT3 inhibitor napabucasin prevented tumour growth and induced the expression of calreticulin and the protein disulfide isomerase family A member 3 (PDIA3; also known as ERp57) but suppressed that of CD47 and GLUT1. Meanwhile, the amount of tumour‐infiltrated DCs and macrophages increased, along with the expression of costimulatory molecules. More CD4+ and CD8+ T cells accumulated in tumour tissues, and CD8+ T cells had lower expression of checkpoint molecules such as lymphocyte activation gene 3 protein (LAG‐3) and programmed cell death protein 1 (PD‐1). Significantly, the antitumour immune memory response was induced by treatment targeting STAT3. These findings provide a new mechanism for targeting STAT3‐induced ICD in HCC, and confirms STAT3 as a potential target for the treatment of HCC via reshaping the tumour immune microenvironment.

Blockade of interleukin 10 potentiates antitumour immune function in human colorectal cancer liver metastases

ObjectiveProgrammed cell death protein 1 (PD-1) checkpoint inhibition and adoptive cellular therapy have had limited success in patients with microsatellite stable colorectal cancer liver metastases (CRLM). We sought to evaluate...

Proteomic analysis reveals USP7 as a novel regulator of palmitic acid-induced hepatocellular carcinoma cell death

Nutrient surplus and consequent free fatty acid accumulation in the liver cause hepatosteatosis. The exposure of free fatty acids to cultured hepatocyte and hepatocellular carcinoma cell lines induces cellular stress, organelle adaptation, and subsequent cell death. Despite many studies, the mechanism associated with lipotoxicity and subsequent cell death still remains poorly understood. Here, we have used the proteomics approach to circumvent the mechanism for lipotoxicity using hepatocellular carcinoma cells as a model. Our quantitative proteomics data revealed that ectopic lipids accumulation in cells severely affects the ubiquitin-proteasomal system. The palmitic acid (PA) partially lowered the expression of deubiquitinating enzyme USP7 which subsequently destabilizes p53 and promotes mitotic entry of cells. Our global phosphoproteomics analysis also provides strong evidence of an altered cell cycle checkpoint proteins’ expression that abrogates early G2/M checkpoints recovery with damaged DNA and induced mitotic catastrophe leading to hepatocyte death. We observe that palmitic acid prefers apoptosis-inducing factor (AIF) mediated cell death by depolarizing mitochondria and translocating AIF to the nucleus. In summary, the present study provides evidence of PA-induced hepatocellular death mediated by deubiquitinase USP7 downregulation and subsequent mitotic catastrophe.

Mecheliolide elicits ROS-mediated ERS driven immunogenic cell death in hepatocellular carcinoma

The nonnegligible reason for the poor prognosis of hepatocellular carcinoma (HCC) is resistance to conventional chemotherapy. Immunogenic cell death (ICD) is a rare immunostimulatory form of cell death that can reengage the tumor-specific immune system. ICD can improve the clinical outcomes of chemotherapeutics by promoting a long-term cancer immunity. The discovery of potential ICD inducers is emerging as a promising direction. In the present study, micheliolide (MCL), a natural guaianolide sesquiterpene lactone, was screened out by the virtual screening strategies, identified as an inhibitor of thioredoxin reductase (TrxR) and was evaluated to have high potential to induce ICD. Here, we showed that MCL induced ICD-associated DAMPs (damage-associated molecular patterns, such as CRT exposure, ATP secretion and HMGB1 release). MCL significantly triggered the regression of established tumors in an immunocompetent mouse vaccine model, and induced ICD (DCs maturation, the stimulation of CD4+, and CD8+ T-cells responses) in vivo. Mechanistically, we found that the magnitude of ICD-associated effects induced upon exposure of HCC cells to MCL was dependent on the generation of reactive oxygen species (ROS)-mediated endoplasmic reticulum stress (ERS). In addition, the suppression of ROS normalized MCL-induced ERS, in contrast, the downregulation of TrxR synergized with the ERS driven by MCL. We also systematically detected the H2O2 generation using Hyper7 sensors in HCC cells exposed to MCL. Notably, MCL inhibited the development of HCC organoids. Collectively, our results reveal a potential association between the TrxR inhibitors and ICD, presenting valuable insights into the MCL-activated ICD in HCC cells.

Stable Reconstitution of Gasdermin-E in a Gasdermin-E-Deficient Head and Neck Squamous Cell Carcinoma Mouse Cell Line Enhances Pyroptosis-Mediated Release of Tumor Immunogenic Molecules

<h3>Purpose/Objective(s)</h3> Gasdermin-E (GSDME) is known to potentiate immunogenic cell death in many tumor types after exposure to anti-cancer agents in a caspase-3 dependent manner. This GSDME-mediated release of immunostimulatory proteins, such as HMGB1, has been shown to increase tumor immunogenicity in mouse model systems of melanoma and colon cancer, resulting in reduced tumor load and lower distal metastasis. We sought to evaluate the role of GSDME-mediated cell death in human papillomavirus-positive (HPV+) head and neck squamous cell carcinoma (HNSCC) mouse cell lines. <h3>Materials/Methods</h3> To test whether HNSCC exhibits a GSDME-associated anti-tumor response, two HPV+ HNSCC mouse cell lines, MTEC and TC-1, were screened for GSDME expression by Western blot and then treated with apoptotic agents (raptinal, cisplatin, etoposide, and UV). Primary outcome measures were HMGB1 release (a potent immunostimulatory factor), percent propidium iodide (%PI) uptake (an indicator of plasma membrane damage and pyroptosis) and cell morphology. Using retroviral transduction, MTEC cells were reconstituted with GSDME, and single cell clones expressing comparable levels of recombinant mouse wild type (WT) GSDME and a caspase-3-uncleavable inactive mutant (Aspartate 270/Glutamate) D270A GSDME were selected. Control MTEC transduced with empty vector (EV) were also generated. Single cell clones were tested <i>in vitro</i> with apoptotic agents and evaluated for HMGB1 release, %PI uptake, and cell morphology. <h3>Results</h3> Western blot analysis demonstrated GSDME expression in TC-1 but not MTEC cells. Following treatment with apoptotic agents, TC-1 cells demonstrated HMGB1 release and increased %PI uptake as well as a distinct secondary necrotic phenotype characterized by ballooning of the plasma membrane on morphological analysis. This was not seen in MTEC cells. To examine whether the absence of GSDME in MTEC cells correlated with reduced release of immune-stimulatory molecules, MTEC cells stably reconstituted with GSDME were treated with apoptotic agents. Unlike MTEC cells expressing the uncleavable D270A GSDME or EV control, MTEC cells expressing WT GSDME demonstrated a significant release of HMGB1 and increased %PI uptake. Morphological analysis demonstrated significant ballooning of the plasma membrane only in the WT GSDME MTEC cells. <h3>Conclusion</h3> Treatment with apoptotic agents induces a GSDME-dependent pyroptotic cell death in MTEC and TC-1 cells as evidenced by HMGB1 release, increased %PI uptake, and cell morphology. As pyroptotic cell death of cancer cells induces anti-tumor immunity through the release of HMGB1 and other immunostimulatory factors, promoting GSDME-dependent pyroptosis might be a strategy to overcome treatment resistance in some HNSCC.

Blocking Adipor1 enhances radiation sensitivity in Hepatoma Carcinoma Cells

In this study, we aimed to elucidate the roles of Adipor1 in radiation-induced cell death of Hepatocellular carcinoma (HCC). The human HCC cell line MHCC97-H and HepG2 were used to investigate the underlying mechanisms. Western blotting was used to detect protein expression, and flow cytometry was used to detect cell cycle and cell death. Orthotopic allograft HCC models were established in Rats. LV-Adipor1-RNAi virus were injected into the tumor before radiation. Such parameters as tumor diameter, blood indicators, and liver function index were detected.In vitro results indicated that Adipor1 knockdown enhanced radiation-induced cell death and DNA damage, and inhibited cell cycle arrest at the G2/M and autophagy, leading to increased apoptosis. In vivo experiments showed that Adipor1 knockdown increased radiosensitivity and significantly inhibited liver tumor growth, upregulated the number of red blood cell, platelet count and Hemoglobin content, decreased the content of ALT, AST and ALP. To sum up, Adipor1 blockade enhance therapeutic effects of radiation by inhibiting cell cycle arrest and autophagy, and promoting DNA damage and apoptosis in Hepatoma Carcinoma Cells.

Local immune checkpoint blockade therapy by an adenovirus encoding a novel PD-L1 inhibitory peptide inhibits the growth of colon carcinoma in immunocompetent mice

A novel peptide that interferes with the PD-1/PD-L1 immune checkpoint pathway, termed PD-L1 inhibitory peptide 3 (PD-L1ip3), was computationally designed, experimentally validated for its specific binding to PD-L1, and evaluated for its antitumor effects in cell culture and in a mouse colon carcinoma syngeneic murine model. In several cell culture studies, direct treatment with PD-L1ip3, but not a similar peptide with a scrambled sequence, substantially increased death of CT26 colon carcinoma cells when co-cultured with murine CD8+ T cells primed by CT26 cell antigens. In a syngeneic mouse tumor model, the growth of CT26 tumor cells transduced with the PD-L1ip3 gene by an adenovirus vector was significantly slower than that of un-transduced CT26 cells in immunocompetent mice. This tumor growth attenuation was further enhanced by the coadministration of the peptide form of PD-L1ip3 (10 mg/kg/day). The current study suggests that this peptide can stimulate host antitumor immunity via blockade of the PD-1/PD-L1 pathway, thereby increasing CD8+ T cell-induced death of colon carcinoma cells. The tumor site-specific inhibition of PD-L1 by an adenovirus carrying the PD-L1ip3 gene, together with direct peptide treatment, may be used as a local immune checkpoint blockade therapy to inhibit colon carcinoma growth.

Auranofin induces urothelial carcinoma cell death via reactive oxygen species production and synergy with cisplatin.

Urothelial carcinoma (UC) is one of the most common cancer types of the urinary tract. UC is associated with poor 5-year survival rate, and resistance to cisplatin-based therapy remains a challenge for invasive bladder cancer treatment. Therefore, there is an urgent need to develop new drugs for advanced UC therapy. Auranofin (AF) was developed over 30 years ago for the treatment of rheumatoid arthritis and has been reported to exert an antitumor effect by increasing the level of reactive oxygen species (ROS) in cancer cells. The aim of the present study was to examine the effects of AF on cancer cell proliferation, cell cycle and apoptosis, either alone or in combination with cisplatin. AF induced cell death in two separate cell lines, HT 1376 and BFTC 909, in a concentration- and time-dependent manner by inducing cell cycle arrest. However, the distribution of cells in different phases of the cell cycle differed between the two cell lines, with G0/G1 cell cycle arrest in HT 1376 cells and S phase arrest in BFTC 909 cells. In addition, AF induced apoptosis in HT 1376, as well as redox imbalance in both HT 1376 and BFTC 909 cells. Cell viability was rescued following treatment with N-acetyl-L-cysteine, a ROS scavenger. Furthermore, AF treatment synergistically increased the cytotoxicity of HT 1376 and BFTC 909 cells when combined with cisplatin treatment. These findings suggest that AF may represent a potential candidate drug against UC and increase the therapeutic effect of cisplatin.

MLH1 mediates cytoprotective nucleophagy to resist 5-Fluorouracil-induced cell death in colorectal carcinoma.

Colorectal Cancer (CRC) with Microsatellite instability (MSI) and mutLhomolog-1 (MLH1) gene deficiency are less aggressive than MLH1 proficient cancers. MLH1 is involved in several cellular processes, but its connection with the autophagy-dependent cellular response towards anticancer drugs remains unclear. In this study, we aimed to investigate the interaction between MLH1 and the autophagy marker LC3, which facilitated nucleophagy induction, and its potential role in determining sensitivity to 5-Fluorouracil (5-FU) induced cell death. To examine the role of MLH1 in DNA-damage-induced nucleophagy in CRC cells, we utilized a panel of MLH1 deficient and MLH1 proficient CRC cell lines. We included a parental HCT116 cell line (MLH1-/-) and its isogenic cell line HCT116 MLH1+/- in which a single allele of the MLH1 gene was introduced using CRISPR-Cas9 gene editing. We observed that MLH1 proficient cells were less sensitive to the 5-FU-induced cytotoxic effect. The 5-FU induced DNA damage led to LC3 up-regulation, which was dependent on MLH1 overexpression. Moreover, immunofluorescence and immunoprecipitation data showed LC3 and MLH1 were colocalized in CRC cells. Consequently, MLH1 dependent 5-FU-induced DNA damage contributed to the formation of micronuclei. These micronuclei colocalize with autolysosome, indicating a cytoprotective role of MLH1 dependent nucleophagy. Interestingly, siRNA knockdown of MLH1 in HCT116 MLH1+/- prevented LC3 upregulation and micronuclei formation. These novel data are the first to show an essential role of MLH1 in mediating the chemoresistance and survival of cancer cells by increasing the LC3 expression and inducing nucleophagy in 5-FU treated CRC cells.

Exploiting redox vulnerabilities to induce ovarian carcinoma cell death: a novel role for tocotrienols

Exploiting redox vulnerabilities to induce ovarian carcinoma cell death: a novel role for tocotrienols

Trans-arterial chemoembolization as a loco-regional inducer of immunogenic cell death in hepatocellular carcinoma: implications for immunotherapy.

BackgroundModulation of adaptive immunity may underscore the efficacy of trans-arterial chemoembolization (TACE). We evaluated the influence of TACE on T-cell function by phenotypic lymphocyte characterization in samples of patients undergoing...

MP66-07 BCG INVOKES SUPERIOR STING-MEDIATED INNATE IMMUNE RESPONSE OVER RADIOTHERAPY IN A CARCINOGEN MURINE MODEL OF UROTHELIAL CANCER

INTRODUCTION AND OBJECTIVE:Radiation-induced DNA damage is known to trigger immunogenic tumor cell death and consequent immune response in urothelial carcinoma, however the local immune cell compos...

Xanthoangelol modulates Caspase-1-dependent pyroptotic death among hepatocellular carcinoma cells with high expression of GSDMD

• XAG exhibits anti-proliferation in HuH7 and HepG2 cells. • XAG induces pyroptotic death in HuH7 cell line with concomitant activation of NLRP3/Caspase-1/GSDMD pathway. • XAG modulates caspase-1-dependent apoptosis in GSDMD-low HepG2 cells. • XAG functions as an anti-tumor agent by restraining the activation of MAPK and NF-κB signaling pathways. Xanthoangelol (XAG), a major chalcone presents in Angelica keiskei , has been employed in research to develop functional supplements or drugs due to its various pharmacological activities. Here, we investigated the underlying mechanism of XAG-induced cell death in hepatocellular carcinoma (HCC). We found that XAG inhibited the cell viability of either HepG2 or HuH7cells, and induced pyroptotic death in HuH7 cell with concomitant activation of NOD-like receptor family pyrin domain containing 3 (NLRP3)/Caspase-1/gasdermin D (GSDMD) pathway. However, in GSDMD-low HepG2 cells, Caspase-1 expression modulated the underlying XAG-induced apoptosis pathway, thereby regulating cell death. VX-765, a special inhibitor of caspase-1, attenuated XAG-induced pyroptosis and apoptosis. Additionally, mitogen-activated protein kinase (MAPK) and NF-κB signaling pathway were suppressed by XAG. These findings suggest that XAG is a promising therapeutic agent through induction of caspase-1 mediated pyroptosis and apoptosis depend on the expression of GSDMD in HCC cells.

Davidone C Induces the Death of Hepatocellular Carcinoma Cells by Promoting Apoptosis and Autophagy.

Davidone C is a newly discovered flavonoid compound purified from the ethyl acetate-soluble fraction of Sophora davidii (Franch.) Skeels. This study explored the anti-tumor activity of davidone C on hepatocellular carcinoma HepG2 and Bel-7402 cells and its mechanism through MTT method, morphological observation, flow cytometry and Western blotting. The results showed that davidone C significantly inhibited the proliferation of HepG2 and Bel-7402 cells in a time- and dose-dependent manner. The morphological changes of apoptotic cells can be observed under an inverted microscope, such as cell floating, chromosome condensation, apoptotic bodies, and other phenomena. The expressions of Bax, cleaved caspase-9, cleaved caspase-3 and cleaved PARP increased with the increase of dosage while Bcl-2 decreased, suggesting that the apoptotic mechanism might be related to the mitochondrial apoptotic pathway. Moreover, davidone C administration can down-regulate the expression of Grp78, and simultaneously up-regulate the expression of caspase-7 and caspase-12, indicating that the apoptotic mechanism might be related to the ERS pathway. In addition, davidone C can down-regulate the expression of p62, and simultaneously up-regulate the expression of LC3-I and LC3-II with a quantitative dependence, suggesting that the mechanism of apoptosis may be related to the autophagy signal pathway. All these results showed davidone C has potential effects on hepatocellular carcinoma.

Proteasome inhibitors decrease paclitaxel‑induced cell death in nasopharyngeal carcinoma with the accumulation of CDK1/cyclin B1.

Southeast Asia is a region with high incidence of nasopharyngeal carcinoma (NPC). Paclitaxel is the mainstay for the treatment of advanced nasopharyngeal cancer. The present study investigated the effect of proteasome inhibitors on the therapeutic effect of paclitaxel and its related mechanism. The present data from Cell Counting Kit-8 and flow cytometry assays demonstrated that appropriate concentrations of proteasome inhibitors (30 nM PS341 or 700 nM MG132) reduced the lethal effect of paclitaxel on the nasopharyngeal cancer cells. While 400 nM paclitaxel effectively inhibited cell division and induced cell death, proteasome inhibitors (PS341 30 nM or MG132 700 nM) could reverse these effects. Additionally, the western blotting results demonstrated accumulation of cell cycle regulation protein CDK1 and cyclin B1 in proteasome inhibitor-treated cells. In addition, proteasome inhibitors combined with paclitaxel led to decreased MCL1 apoptosis regulator, BCL2 family member/Caspase-9/poly (ADP-ribose) polymerase apoptosis signaling triggered by CDK1/cyclin B1. Therefore, dysfunction of CDK1/cyclin B1 could be defining the loss of paclitaxel lethality against cancer cells, a phenomenon affirmed by the CDK1 inhibitor Ro3306. Overall, the present results demonstrated that a combination of paclitaxel with proteasome inhibitors or CDK1 inhibitors is antagonistic to effective clinical management of NPC.

Exosome-mediated delivery of SCD-1 siRNA promoted the death of anaplastic thyroid carcinoma cells via regulating ROS level.

Anaplastic thyroid carcinoma (ATC) is one of the most aggressive cancers in the world. Stearoyl-CoA desaturase-1 (SCD-1) is one of major enzymes in the de novo synthesis of fatty acids and is related to cancer aggressiveness and poor patient prognosis. The study aimed to construct exosomes loaded SCD-1 interference, investigate its effects and mechanisms on the cell proliferation and apoptosis of ATC cells. The expressions of SCD-1 in normal thyroid cell line and ATC cell lines were determined by qRT-PCR and western blotting, respectively. Exosomes were prepared and purification then loaded with SCD-1 siRNA by electroporation and observed by transmission electron microscopy. Higher SCD-1 mRNA and protein levels were found in ATC cell lines compared than normal thyroid cell line (P < 0.05), and both Hth-7 and FRO cells could uptake PKH67-labeled exosomes. The effects of exosomes loaded SCD-1 siRNA on ATC cells were measured by CCK8 assay and apoptosis detection kit. When compared with control group, the cell viability significantly decreased in both two ATC cell lines taken up exosomes loaded SCD-1 siRNA (P < 0.001), and apoptotic and necrotic cells obviously increased (P < 0.05). In order to explore the mechanism of exosomes loaded SCD-1 on ATC, the ROS level was detected by fluorescence reagent. It was found that exosomes loaded SCD-1 siRNA significantly increased intracellular ROS level of ATC cells (P < 0.05). Exosomes loaded SCD-1 siRNA inhibited ATC cellular proliferation and promoted cellular apoptosis, and the mechanisms involved maybe the regulation of fatty acids metabolism and ROS level. Our study provides a promising therapeutic strategy for ATC.