In vitro establishment of cis-diammine-dichloroplatinum(II) resistant lung cancer cell line and modulation of apoptotic gene expression as a mechanism of resistant phenotype

Expression profile-based screening for critical genes reveals S100A4, ACKR3 and CDH1 in docetaxel-resistant prostate cancer cells

Docetaxel is a first-line anticancer drug widely used in the treatment of advanced prostate cancer. However, its therapeutic efficacy is limited by its side effects and the development of chemoresistance by the tumor. Using a gene differential expression microarray, we identified 449 genes differentially expressed in docetaxel-resistant DU145 and PC3 cell lines as compared to docetaxel-sensitive controls. Moreover, western blotting and immunohistochemistry revealed altered expression of S100A4, ACKR3 and CDH1in clinical tumor samples. Cytoscape software was used to investigate the relationship between critical proteins and their signaling transduction networks. Functional and pathway enrichment analyses revealed that these signaling pathways were closely related to cellular proliferation, cell adhesion, cell migration and metastasis. In addition, ACKR3 knockout using the crispr/cas9 method andS100A4knockdownusing targeted shRNA exerted additive effects suppressing cancer cell proliferation and migration. This exploratory analysis provides information about potential candidate genes. It also provides new insight into the molecular mechanism underlying docetaxel-resistance in androgen-independent prostate cancer and highlights potential targets to improve therapeutic outcomes.

Inhibitor of DNA binding 3 reverses cisplatin resistance in human lung adenocarcinoma cells by regulating the PI3K/Akt pathway

Inhibitor of DNA-binding 3 (ID3) is a helix-loop-helix transcription factor that is associated with cell proliferation, differentiation and drug resistance in human cancer, and with anticancer effects in certain types of cancer cells. The present study investigated whether and how ID3 was involved in multidrug resistance (MDR) in human cisplatin (DDP)-resistant A549/DDP lung adenocarcinoma cells. The underlying mechanism of action was investigated in vitro. Cell Counting Kit-8 (CCK-8) and flow cytometry assays demonstrated that overexpression of ID3 enhanced chemosensitivity and decreased drug efflux in A549/DDP cells. Reverse transcription-quantitative polymerase chain reaction revealed that the expression of anti-apoptotic gene B-cell lymphoma-2 was significantly downregulated in cells expressing exogenous ID3 (P<0.05). These results indicated that ID3 may synergize with DDP to increase apoptosis in A549/DDP cells. ID3 overexpression modulated the activity of phosphoinositide 3-kinase/RAC serine/threonine-protein kinase signaling and downregulated the expression of multi-drug resistance protein-1, indicating that ID3 expression can reverse multi-drug resistance in A549/DDP cells. Collectively, these results indicate that ID3 is a potential effective chemotherapeutic target for the treatment of human DDP-resistant A549 lung adenocarcinoma therapy.

Reversal of Cisplatin resistance by epigallocatechin gallate is mediated by downregulation of axl and tyro 3 expression in human lung cancer cells

Lung cancer is still the number one cause of death from cancer worldwide. The clinical effect of platinum-based chemotherapy for non-small cell lung cancer is constrained by the resistance to drug. To overcome chemo-resistance, various modified treatment including combination therapy has been used, but overall survival has not been improved yet. In this study, chemo-resistant lung cancer cells, A549/Cis and H460/Cis, were developed by long-term exposure of cells to cisplatin and the proliferative capability of these resistant cells was verified to be reduced. We found cytotoxic effect of epigallocatechin gallate (EGCG), a major catechin derived from green tea, on both the parental lung cancer cells, A549 and H460, and their cisplatin resistant cells, A549/Cis and H460/Cis. ELISA and Western blot analysis revealed that EGCG was able to increase interlukine-6 (IL-6) production per cell, whereas its downstream effector Signal transducers and activators of transcription 3 (STAT3) phosphorylation was not changed by EGCG, indicating that IL-6/STAT3 axis is not the critical signaling to be inhibited by EGCG. We next found that EGCG suppresses the expression of both Axl and Tyro 3 receptor tyrosine kinases at mRNA and protein level, explaining the cytotoxic effect of EGCG on lung cancer cells, especially, regardless of cisplatin resistance. Taken together, these data suggest that EGCG impedes proliferation of lung cancer cells including their chemo-resistant variants through downregulation of Axl and Tyro 3 expression.

Long-term cisplatin exposure impairs autophagy and causes cisplatin resistance in human lung cancer cells

Cisplatin-based chemotherapy frequently resulted in acquired resistance of cancer cells. The underlying mechanism of such resistance is not fully understood especially the involvement of autophagy and autophagic cell death. This study thus investigated whether an alteration in autophagy could be responsible for cisplatin resistance in the long-term exposure lung carcinoma cells. The cisplatin resistant clone (H460/cis) of H460 cells was established by exposing the cells with gradually increasing concentrations of cisplatin until chemoresistance acquisition was elucidated by MTT, Hoechst 33342 staining and comet assays. Degree of autophagosome formation and level of LC3 marker were evaluated by acridine orange and western blot analysis, respectively. H460/cis cells exhibited irregular shape with ~3-fold resistant to cisplatin-induced apoptosis compared with H460 cells. Proteins analysis for LC3 indicated that the levels of LC3 in resistant cells were significantly lower than those in H460 cells. Moreover, autophagosome formation detected by acridine orange staining was dramatically reduced in the resistant cells, suggesting the role of autophagy in attenuating of cisplatin-induced cell death. Further, co-treatment of cisplatin with autophagy inducer, trifluorperazine, could resensitize H460/cis cells to cisplatin-induced cell death. Our findings reveal the novel mechanisms causing cisplatin resistance in lung carcinoma cells after long-term drug exposure regarding autophagy.

Pentoxifylline sensitizes human cervical tumor cells to cisplatin-induced apoptosis by suppressing NF-kappa B and decreased cell senescence

BACKGROUND

Worldwide, cervical cancer is the second most common causes of cancer in women and represents an important mortality rate. Cisplatin (CIS) is a very important antitumoral agent and can lead tumor cells toward two important cellular states: apoptosis and senescence. In some types of cancers pentoxifylline (PTX) sensitizes these cells to the toxic action of chemotherapeutics drugs such as adriamycin, inducing apoptosis. In the present work, we studied in vitro whether PTX alone or in combination with CIS induces apoptosis and/or senescence in cervix cancer HeLa and SiHa cell lines infected with HPV types 16 and 18, respectively, as well as in immortalized keratinocytyes HaCaT cells.

METHODS

HeLa (HPV 18+), SiHa (HPV 16+) cervix cancer cells and non-tumorigenic immortalized HaCaT cells (control) were treated with PTX, CIS or both. The cellular toxicity and survival fraction of PTX and CIS were determinate by WST-1 and clonogenic assays respectively. Apoptosis, caspase activation and phosphorylation of ERK1/2, p38, p65 (NF-κB), Bcl-2 and Bcl-XL anti-apoptotic proteins were determinated by flow cytometry. Senescence by microscopy. Phosphorylation of IκBα and IκB total were measured by ELISA. Pro-apoptotic, anti-apoptotic and senescence genes, as well as HPV-E6/7 mRNA expression, were detected by RT-PCR.

RESULTS

Our results show that after 24 hours of incubation PTX per se is toxic for cancer cells affecting cell viability and inducing apoptosis. The toxicity in HaCaT cells was minimal. CIS induces apoptosis in HeLa and SiHa cells and its effect was significantly increases when the cells were treated with PTX + CIS. In all studies there was a direct correlation with levels of caspases (-3, -6, -7, -9 and -8) activity and apoptosis. CIS induces important levels of senescence and phosphorylation of ERK1/2, p38, p65/RELA, and IκBα, and decreased the expression of anti-apoptotic protein Bcl-XL. Surprisingly these levels were significantly reduced by PTX in tumor cells, and at the same time, increases the expression of pro-apoptotic genes.

CONCLUSION

PTX sensitizes cervical cancer cells to CIS-induced apoptosis and decreases the CIS-induced senescence in these cells via inhibition of NF-κB signaling pathway; diminishes expression of antiapoptotic proteins and the activation of caspases.

Establishment and characterization of a new drug surviving cell line Am1010, derived directly from muscle metastases of a human lung adenocarcinoma patient with multi-drug-resistance to cisplatin, taxol, and gefitinib

AIM

To Characterize a new human lung cancer cell line Am1010, derived from drug-surviving cells (DSCs).

METHODS

The Am1010 cell line was established after 4 cycles of chemotherapy from an arm muscle metastatic tumor of a patient diagnosed with lung adenocarcinoma. The cell line has been remained in continuous culture for more than one year during this study.

RESULTS

The Am1010 cell line demonstrated in vitro multi-drug-resistance to cisplatin, taxol, and gefitinib. The Am1010 cell doubling time without drug treatment was 42.395 h. The IC(50) value of cisplatin was 4.299 micromol/L and >10 micromol/L for the Am1010 and P0318 (a cell line derived from non-DSCs) cells, respectively. The IC(50) value of taxol was 0.067 micromol/L and >1 micromol/L for the Am1010 and P0318 cells, respectively. The IC(50) value of gefitinib was 15.233 micromol/L and >70 micromol/L for Am1010 and P0318 cells, respectively. 11 genes involved in the focal adhesion and cell adhesion pathways were found to be differentially expressed. The cells of Am1010 have a significantly larger chromosome number than most lung cancer cell lines.

CONCLUSION

This novel DSCs derived lung cancer cell line will be a valuable in vitro tool for the investigation of lung cancer drug resistance and metastasis.

Establishment of in-vitro models of chemotherapy resistance

Chemotherapy resistance is one of the most prevalent obstacles to the treatment of cancer, resulting in increased mortality and prolonged exposure to cytotoxic agents with no treatment benefit. One of the tools utilized in the study of mechanisms of chemotherapy resistance are established cell lines derived from human neoplasms. These cell lines can be challenged in vitro with controlled chemotherapy doses to produce chemotherapy-resistant variants. Analysis of these novel chemotherapy-resistant cell lines may then identify genetic and proteomic changes which are associated with the resistant phenotype. Two very important mediators of chemotherapy resistance (P-glycoprotein and multidrug resistance protein-1) were initially identified in chemotherapy-resistant cell lines. To make these in-vitro studies clinically relevant it is, however, necessary to duplicate as far as possible the treatment conditions used in vivo. Considerations should include clinically relevant drug concentrations, such as those derived from peak plasma values, and the type of treatment schedule to be employed.

Microenvironment effects on promoting upregulation of matrix metalloproteinases in Bcl-2-overexpressing renal cell carcinoma as a response to doxorubicin treatment inducing the production of metastasis

Dysfunction in apoptosis has been suggested to play an important role in the development of a distant metastasis. The Bcl-2 gene plays a key role in the response to chemotherapeutic agents, and its upregulation protects the cells from apoptosis by inactivating the Bax proteins through heterodimerization of Bcl-2/Bax. However, there is no direct evidence showing that the upregulation of Bcl-2 increases the antiapoptotic effects against chemotherapeutic agents and is associated with the production of a distant metastasis. In this study, the role of Bcl-2 in the production of distant metastasis was investigated by examining the activity of caspase-3 and the expression of matrix metalloproteinases (MMPs) after transfecting the Bcl-2 gene into human renal cell carcinoma cells (SN12C). In addition, the production of a distant metastasis was examined in an orthotopic animal model. In vitro, the SN12C/smb2 cells were more resistant to doxorubicin (DXR) than the untreated parental cells. The IC50 of the SN12C/smb2 was 50% higher than that of the parental cells. In addition, the caspase-3 activity of the SN12C/smb2 cells was lower than that of the parental cells after the DXR treatment. On the other hand, there was no difference in the expression of MMP-2 and MMP-9 between the SN12C and SN12C/smb2 cell lines. However, the SN12C/smb2 cells had a higher metastatic potential than the parental cells in the orthotopic animal model. Unlike the results from the in vitro analysis, the expression of MMP-2 and MMP-9 in the kidney tumors produced by the SN12C/smb2 cells was higher than in the kidney tumors produced by the SN12C/vector. These results show that the upregulation of Bcl-2 in human renal cell carcinoma cells induces drug resistance to DXR. Moreover, Bcl-2 induced the expression of MMP in tumors grown in the orthotopic sites even though no appreciable effects were observed in the in vitro condition. When the in vitro and in vivo data were combined, it appears that the Bcl-2 gene initially affects the response to DXR. The cells that survive the DXR treatment then have a chance to become metastatic by increasing the levels of MMP in an orthotopic environment.

Action of solamargine on human lung cancer cells--enhancement of the susceptibility of cancer cells to TNFs

Solamargine (SM), isolated from Solanum incanum herb, displayed a superior cytotoxicity in four human lung cancer cell lines. The half-inhibitory concentrations (IC50), of the cell viability assay for H441, H520, H661 and H69 cells were 3, 6.7, 7.2 and 5.8 microM, respectively. SM-induced apoptosis of these cells by PS externalization in a dose-dependent manner and increased sub-G1 fraction were observed. Quenching of the expression of tumor necrosis factor receptors (TNFRs) during the progress of human lung carcinogenesis has been previously reported. SM may induce cell apoptosis via modulating the expression of TNFRs and their subsequent TRADD/FADD signal cascades. Subsequently, SM treatment increased the binding activities of TNF-alpha and TNF-beta to the lung cancers, and the intrinsic TNFs-resistant cancer cells became susceptible to TNF-alpha and -beta. In addition, SM caused release of cytochrome c, downregulation of anti-apoptotic Bcl-2 and Bcl-xL, increase of caspase-3 activity, and DNA fragmentation. Thus, SM could modulate the expressions of TNFRs and Bcl-2, and might be a potential anticancer agent for TNFs and Bcl-2 related resistance of human lung cancer cells.

Intrapleural hyperthermic perfusion with chemotherapy increases apoptosis in malignant pleuritis

BACKGROUND

Previously, we reported on the effectiveness of intrapleural hyperthermic perfusion with chemotherapy, a new treatment we developed for patients with malignant pleuritis. The present study analyzes the mechanism of the effectiveness of this therapy by examining the induction ratio of apoptosis among tumor cells following the perfusion treatment.

METHODS

This study included 11 consecutive patients with primary pulmonary adenocarcinoma and accompanying pleural seedlings and pleural effusions containing tumor cells but without distant metastasis. All patients underwent surgical resection of the primary lesion and then received sequential perfusion treatment. Tumor cells collected from the effusion both before and again at 24 hours following the perfusion treatment were subsequently examined using an immunocytochemical stain to determine apoptosis among tumor cells. The percentage of positively stained cells was expressed as the apoptotic index. We compared the survival rate of these 11 patients with the survival rate of a second group of 11 patients with malignant pleuritis who underwent surgical resection of the primary lesion but who did not receive the perfusion treatment (control group).

RESULTS

The ratio of spontaneous apoptosis of untreated tumor cells was 2.8% +/- 2.0%. Following the perfusion, apoptosis among tumor cells was 25.2% +/- 4.6%, clearly a significant increase. While the median survival time for patients receiving the perfusion treatment was 20 months, the median survival time for the control group was 6 months.

CONCLUSIONS

In patients with malignant pleuritis, intrapleural hyperthermic perfusion with chemotherapy induced potent apoptosis of tumor cells in the pleural cavity and also improved the survival rate of these patients as compared with patients who did not receive the perfusion treatment.

Action of solamargine on TNFs and cisplatin-resistant human lung cancer cells

A loss of TNF receptors expression has been found in advanced lung cancers, and human A549 lung adenocarcinoma cells are resistant to the cytotoxic effects of TNF-alpha and cisplatin. Here, the mechanisms of the drug resistance of A549 were extensively studied by gene modulation of the cells by solamargine (SM) which was isolated from Solanum incanum herb. SM induced morphological changes of chromatin condensation, DNA fragmentation, and sub-G(1) peak in a DNA histogram of A549 cells, indicating cell death by apoptosis. SM elevated the expressions of TNF-R1 and -R2 and overcame the resistance of A549 cells to TNF-alpha and -beta. The recruitment of TRADD, FADD, and activation of caspase-8 and -3 in SM-treated A549 cells evidenced the activation of TNFRs signal transduction. In addition, release of cytochrome c from mitochondria, down-expression of Bcl-2 and Bcl-x(L), up-regulation of Bax, and caspase-9 activities were observed in SM-treated A549 cells. Combinational treatment of SM and cisplatin synergistically enhanced caspase-8, -9, and -3 activities in A549 cells. Thus, SM sensitizes A549 cells through TNFRs and mitochondria-mediated pathways and may have anticancer potential against TNFs- and cisplatin-resistance lung cancer cells.

Pharmacogenetics of anticancer drug sensitivity in non-small cell lung cancer

In mammalian cells, the process of malignant transformation is characterized by the loss or down-regulation of tumor-suppressor genes and/or the mutation or overexpression of proto-oncogenes, whose products promote dysregulated proliferation of cells and extend their life span. Deregulation in intracellular transduction pathways generates mitogenic signals that promote abnormal cell growth and the acquisition of an undifferentiated phenotype. Genetic abnormalities in cancer have been widely studied to identify those factors predictive of tumor progression, survival, and response to chemotherapeutic agents. Pharmacogenetics has been founded as a science to examine the genetic basis of interindividual variation in drug metabolism, drug targets, and transporters, which result in differences in the efficacy and safety of many therapeutic agents. The traditional pharmacogenetic approach relies on studying sequence variations in candidate genes suspected of affecting drug response. However, these studies have yielded contradictory results because of the small number of molecular determinants of drug response examined, and in several cases this approach was revealed to be reductionistic. This limitation is now being overcome by the use of novel techniques, i.e., high-density DNA and protein arrays, which allow genome- and proteome-wide tumor profiling. Pharmacogenomics represents the natural evolution of pharmacogenetics since it addresses, on a genome-wide basis, the effect of the sum of genetic variants on drug responses of individuals. Development of pharmacogenomics as a new field has accelerated the progress in drug discovery by the identification of novel therapeutic targets by expression profiling at the genomic or proteomic levels. In addition to this, pharmacogenetics and pharmacogenomics provide an important opportunity to select patients who may benefit from the administration of specific agents that best match the genetic profile of the disease, thus allowing maximum activity.