Murine Lung Carcinoma Cell Line Research Articles

7P - Immunomodulatory effects of Tumor Treating Fields (TTFields) on lung cancer models

Background: Tumor Treating Fields (TTFields) are a clinically approved anti-mitotic treatment modality delivered via noninvasive application of low intensity, intermediate frequency, alternating electric fields. In this study, we evaluated whether TTFields-induced cell death can be perceived as immunogenic. Methods: Human and murine lung carcinoma cell lines were treated with TTFields using the inovitro system. Immunogenic cell death was evaluated by changes in the levels of calreticulin (CRT) on the surface of treated cells, phosphorylation of the translation initiation factor eIF2α, and secretion of ATP and High mobility group box 1 (HMGB1). Activation of immune cells was evaluated using co-culture of bone marrow derived dendritic cells (DCs) with TTFields treated cells. For in-vivo studies, mice orthotopically implanted with lung tumors were treated with TTFields, the immune checkpoint inhibitor anti-PD-1 or a combination of the two modalities. Tumor volume was monitored and flow cytometry analysis was performed for phenotypic characterization of infiltrating immune cells. Results: We demonstrate that cancer cells that died under TTFields application exhibited release of HMGB1, ATP secretion from cells, and ER stress leading to CRT translocation to the cell surface, all of which are cardinal signs of immunogenic cell death. TTFields treated cells promoted in vitro phagocytosis by DCs and DC maturation as well as initiation of inflammation in vivo. The combined treatment of lung tumor-bearing mice with TTFields plus the immune checkpoint inhibitor anti-PD-1 led to a significant decrease in tumor volume compared to anti-PD-1 alone or to the control group. Significant increases in CD45+ tumor infiltrating cells were observed in the TTFields plus anti-PD-1 group. These infiltrating cells demonstrated upregulation of surface PD-L1 expression. Correspondingly, cytotoxic T-cells isolated from these tumors showed higher levels of IFN-γ production relative to untreated mice. Conclusions: Our results demonstrate the potential of TTFields therapy to induce immunogenic cell death and increase the efficacy of anti PD-1 therapy by further enhancing antitumor immunity. Legal entity responsible for the study: Novocure Israel. Funding: Novocure Israel. Disclosure: U. Weinberg, T. Voloshin Sela, Y. Porat, M. Munster, R.S. Schneiderman, C. Tempel Brami, S. Cahal, M. Giladi, A. Kinzel, Y. Palti: Full time employee: Novocure Israel; Stock options, stocks: Novocure. N. Kaynan, S. Davidi, A. Shteingauz, K. Gotlib, E. Zeevi: Full time employee: Novocure Israel; Stock options: Novocure. E. Kirson: Full time employee: Novocure Israe; Stock options, stocks: Novocure; Senior leadership position: Novocure.

Fine Particulate Matter (PM2.5) Promoted the Invasion of Lung Cancer Cells via an ARNT2/PP2A/STAT3/MMP2 Pathway

Accumulating evidence indicates that fine particulate matter (PM2.5) exposure is associated with many cardiopulmonary diseases, particularly lung carcinoma. Nevertheless, the underlying biological mechanisms by which PM2.5 exposure initiates and aggravates lung carcinoma remain elusive. In the present study, we collected PM2.5 in Nanjing and explored the mechanisms underlying the oncogenic roles of PM2.5 in the murine lung carcinoma cell line LLC in vitro and in vivo. PM2.5 was closely attached to and internalized by lung cancer cells. Moreover, PM2.5 increased the production of ARNT2 and the inactivation of the tumor suppressor B56γ-PP2A, which was followed by the activation of ps727STAT3 and the enhancement of invasive ability by MMP-2. Furthermore, we took advantage of an orthotopic lung carcinoma metastasis mouse model to illustrate the prometastatic effect of PM2.5 in vivo; our results suggested that the ARNT2/PP2A/STAT3/MMP-2 cascade played a key role in PM2.5-related oncogenicity. Finally, we observed that PM2.5 was deposited in human lung carcinoma tissues, indicating that this potential pathway may also be involved in human lung carcinoma. These findings demonstrated that fine particulate matter, or PM2.5, promoted the invasion of lung cancer cells via an ARNT2/PP2A/STAT3/MMP2 pathway, which may be targeted to alleviate the tumorigenic effect of PM2.5 in lung cancer.

The soft agar colony formation assay.

Anchorage-independent growth is the ability of transformed cells to grow independently of a solid surface, and is a hallmark of carcinogenesis. The soft agar colony formation assay is a well-established method for characterizing this capability in vitro and is considered to be one of the most stringent tests for malignant transformation in cells. This assay also allows for semi-quantitative evaluation of this capability in response to various treatment conditions. Here, we will demonstrate the soft agar colony formation assay using a murine lung carcinoma cell line, CMT167, to demonstrate the tumor suppressive effects of two members of the Wnt signaling pathway, Wnt7A and Frizzled-9 (Fzd-9). Concurrent overexpression of Wnt7a and Fzd-9 caused an inhibition of colony formation in CMT167 cells. This shows that expression of Wnt7a ligand and its Frizzled-9 receptor is sufficient to suppress tumor growth in a murine lung carcinoma model.

Combining the Antigen Processing Components TAP and Tapasin Elicits Enhanced Tumor-Free Survival

Tpn is a member of the MHC class I loading complex and functions to bridge the TAP peptide transporter to MHC class I molecules. Metastatic human carcinomas often express low levels of the antigen-processing components Tapasin and TAP and display few functional surface MHC class I molecules. As a result, carcinomas are unrecognizable by effector CTLs. The aim of this study is to examine if Tapasin (Tpn) plays a critical role in the escape of tumors from immunologic recognition. To test our hypothesis, a nonreplicating adenovirus vector encoding human Tpn (AdhTpn) was constructed to restore Tpn expression in vitro and in vivo in a murine lung carcinoma cell line (CMT.64) that is characterized by down-regulation of surface MHC class I due to deficiency in antigen-processing components. Ex vivo, Tpn expression increased surface MHC class I and restored susceptibility of tumor cells to antigen-specific CTL killing, and AdhTpn infection of dendritic cells also significantly increased cross-presentation and cross-priming. Furthermore, tumor-bearing animals inoculated with AdhTpn demonstrated a significant increase in CD8(+) and CD4(+) T cells and CD11c(+) dendritic cells infiltrating the tumors. Provocatively, whereas syngeneic mice bearing tumors that were inoculated with AdhTpn a significant reduction in tumor growth and increased survival compared with vector controls, combining AdhTpn inoculation with AdhTAP1 resulted in a significant augmentation of protection from tumor-induced death than either component alone. This is the first demonstration that Tpn alone can enhance survival and immunity against tumors but additionally suggests that Tpn and TAP should be used together as components of immunotherapeutic vaccine protocols to eradicate tumors.

A Folate Receptor?Targeted Lipid Nanoparticle Formulation for a Lipophilic Paclitaxel Prodrug

The anticancer drug paclitaxel has poor aqueous solubility and is difficult to formulate in a lipid-based formulation due to its limited lipid solubility. Paclitaxel-7-carbonyl-cholesterol (Tax-Chol), a prodrug of paclitaxel with increased lipophilicity, was therefore synthesized and evaluated for incorporation into a lipid nanoparticle (LN) formulation, which also contained folate-polyethylene glycolcholesterol (f-PEG-Chol) as a ligand that targets the tumor marker folate receptor (FR). This novel formulation was designed for prolonged systemic circulation and selective targeting of tumor cells with amplified FR expression. Tax-Chol was synthesized. FR-targeted LNs, composed of distearoyl phosphatidylcholine (DSPC)/triolein/Chol oleate/PEG-Chol/f-PEG-Chol (40:40:18:2.0:0.5, mole/mole), were then prepared by solvent dilution followed by diafiltration. FR-targeted LNs containing Tax-Chol were then evaluated for cytotoxicity in KB, a human oral carcinoma cell line, and M109, a murine lung carcinoma cell line, both of which are FR(+) and in FR(-) Chinese hamster ovary (CHO) cells. Furthermore, tumor growth inhibition and animal survival in response to treatment with FR-targeted LNs and control formulations were evaluated in BALB/c mice bearing subcutaneously engrafted M109 tumors. The LNs had a mean diameter of 130 nm and Tax-Chol incoporation efficiency of greater than 90% and exhibited excellent colloidal stability. FR-targeted LNs showed greater uptake and cytotoxicity in FR(+) KB and M109 cells than nontargeted LNs. Furthermore, treatment of mice bearing M109 tumors with FR-targeted LNs resulted in significantly greater tumor growth inhibition and animal survival compared to treatment with nontargeted LNs or paclitaxel formulated in Cremophor EL. FR-targeted LNs containing Tax-Chol are a promising novel formulation for the treatment of FR(+) tumors and further preclinical studies are warranted.

A rapid quantitative assay for the detection of mammalian heparanase activity.

Heparan sulphate (HS) is an important component of the extracellular matrix and the vasculature basal laminar which functions as a barrier to the extravasation of metastatic and inflammatory cells. Cleavage of HS by endoglycosidase or heparanase activity produced by invading cells may assist in the disassembly of the extracellular matrix and basal laminar, and thereby facilitate cell migration. Heparanase activity has previously been shown to be related to the metastatic potential of murine and human melanoma cell lines [Nakajima, Irimura and Nicolson (1988) J. Cell. Biochem. 36, 157-167]. To determine heparanase activity, porcine mucosal HS was partially de-N-acetylated and re-N-acetylated with [3H]acetic anhydride to yield a radiolabelled substrate. This procedure prevented the masking of, or possible formation of, new heparanase-sensitive cleavage sites as has been observed with previous methods of radiolabelling. Heparanase activity in a variety of tissues and cell homogenates including human platelets, colonic carcinoma cells, umbilical vein endothelial cells and rat mammary adenocarcinoma cells (both metastatic and non-metastatic variants) and liver homogenates all degraded the substrate in a stepwise fashion from 18.5 to approximately 13, 8 and finally to 4.5 kDa fragments, as assessed by gel-filtration analysis, confirming the substrate as suitable for the detection of heparanase activity present in a variety of cells and tissues. A rapid quantitative assay was developed with the HS substrate using a novel method for separating degradation products from the substrate by taking advantage of the decreased affinity of the heparanase-cleaved products for the HS-binding plasma protein chicken histidine-rich glycoprotein (cHRG). Incubation mixtures were applied to cHRG-Sepharose columns, with unbound material corresponding to heparanase-degradation products. Heparanase activity was determined for a variety of human, rat and murine cell and tissue homogenates. The highly metastatic rat mammary adenocarcinoma and murine lung carcinoma cell lines had four to ten times the heparanase activity of non-metastatic variants, confirming the correlation of heparanase activity with metastatic potential. Human cancer patients had twice the serum heparanase levels of normal healthy adults. The assay will be valuable for the determination of heparanase activity from a variety of tissue and cell sources, as a diagnostic tool for the determination of heparanase potential, and for the development of specific inhibitors of heparanase activity and metastasis.

Isolation of a mouse cDNA encoding MTJ1, a new murine member of the DnaJ family of proteins

We report the isolation and sequencing of MTJ1, a 1792-bp cDNA from an M27 murine lung carcinoma cell line. The largest ORF within MTJ1 encodes a 63 869-Da protein, containing a 73-amino-acid (aa) sequence (the J domain) that is conserved in proteins of the DnaJ family of chaperonins. The J domain of MTJ1 is bracketed by potential transmembrane domains in a similar configuration to the J domain of the yeast DnaJ-like protein, SEC63. Polyclonal antibodies raised against deduced aa sequences within MTJ1 recognized antigens of 62, 42 and 41 kDa that were enriched in the nuclear and heavy microsome subcellular fractions of murine tumor cells. Northern analysis detected a major 3.2-kb transcript that was present in all murine organs examined, but was relatively underexpressed in brain and heart.

Retinoic acid negatively regulates β4 integrin expression and suppresses the malignant phenotype in a Lewis lung carcinoma cell line

Retinoic acid (RA) is a potent inhibitor of the malignant phenotype and of tumour cell growth. We observed that in vitro RA treatment of a highly metastatic lung carcinoma cell line (C87) induced a marked reduction in the amount of the beta 4 integrin subunit. The downregulation of this adhesion molecule was assessed by immunofluorescence, immunoprecipitation, and northern analysis. In order to investigate the effects of RA on the malignant phenotype in C87 cells we performed morphological and functional analysis after RA treatment. We found that RA was able to produce marked changes in C87 cell shape, increasing the number of flat cells (90% of the total cell population), and significantly inhibiting the malignant and invasive phenotype of C87 cells. RA treatment suppressed their clonogenic potential in soft agar (control, 20 +/- 5; RA, 0), and strongly reduced their chemotactic and chemoinvasive capacity (chemotaxis: control, 231 +/- 5; RA, 28 +/- 0; chemoinvasion: control, 132 +/- 11; RA = 2 +/- 1). FACS analysis and cell count, however, indicated that RA reduced the growth of C87 cells only partially. After 72 h of treatment we observed only a 10% reduction in the S phase fraction of the cell population. Finally, the reduced lung colony-forming ability, observed after i.v. injection of RA-treated cells (lung foci/animal: RA-treated cells, 1 +/- 0.1; untreated, 8.5 +/- 0.8), further supports the conclusion that in this murine lung carcinoma cell line a marked reduction in the expression of the beta 4 integrin subunit is associated with a marked inhibition of the malignant phenotype.

Molecular analysis of deficient class I H-2 antigen expression by mouse lung carcinoma cells.

We have continued our investigations of line lung carcinoma cells to understand the molecular basis of decreased expression of class I H-2 Ag and class I Ag induction with DMSO. We show that line 1, a murine lung carcinoma cell line, has low levels of class I Ag (H-2K, D, and L) because it is deficient in both class I and beta 2-microglobulin (B2M) RNA, and that these mRNA can be coordinately induced with DMSO. Evidence presented herein also shows that IFN-gamma can induce surface expression of class I Ag and suggests that it may act through a different mechanism than DMSO in inducing class I Ag. To further evaluate the regulation of class I expression, H-2Dp genes were transfected into line 1 cells. The transfected H-2 genes appear to be constitutively expressed at much higher levels than are the endogenous class I genes because surface expression of the foreign Dp Ag on the transfectants is elevated relative to the endogenous H-2d haplotype class I Ag. Both Dp surface expression and Dp mRNA are induced after treatment with DMSO. In all the Dp transfectants, we observed higher constitutive levels of class I mRNA as well as increased constitutive levels of endogenous B2M mRNA when compared to control or untransfected line 1 cells, however, we could not correlate these constitutive levels with Dp copy number. These results suggest that the regulation of class I and B2M genes is linked and that expression of class I genes can affect the expression of B2M genes.