scholarly journals CRISPR/Cas9-Mediated TERT Disruption in Cancer Cells

2020 ◽  
Vol 21 (2) ◽  
pp. 653 ◽  
Author(s):  
Luan Wen ◽  
Changzhi Zhao ◽  
Jun Song ◽  
Linyuan Ma ◽  
Jinxue Ruan ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Tumor Cells ◽  
Gene Editing ◽  
Therapeutic Option ◽  
Telomerase Activity ◽  
Telomere Attrition ◽  
Tert Gene ◽  
Cancer Cell Survival

Mammalian telomere lengths are primarily regulated by telomerase, a ribonucleoprotein consisting of a reverse transcriptase (TERT) and an RNA subunit (TERC). TERC is constitutively expressed in all cells, whereas TERT expression is temporally and spatially regulated, such that in most adult somatic cells, TERT is inactivated and telomerase activity is undetectable. Most tumor cells activate TERT as a mechanism for preventing progressive telomere attrition to achieve proliferative immortality. Therefore, inactivating TERT has been considered to be a promising means of cancer therapy. Here we applied the CRISPR/Cas9 gene editing system to target the TERT gene in cancer cells. We report that disruption of TERT severely compromises cancer cell survival in vitro and in vivo. Haploinsufficiency of TERT in tumor cells is sufficient to result in telomere attrition and growth retardation in vitro. In vivo, TERT haploinsufficient tumor cells failed to form xenograft after transplantation to nude mice. Our work demonstrates that gene editing-mediated TERT knockout is a potential therapeutic option for treating cancer.

scholarly journals Osteoblast-Derived Paracrine and Juxtacrine Signals Protect Disseminated Breast Cancer Cells from Stress

Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1366
Author(s):  
Russell Hughes ◽  
Xinyue Chen ◽  
Natasha Cowley ◽  
Penelope D. Ottewell ◽  
Rhoda J. Hawkins ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Survival ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cells ◽  
Metastatic Breast ◽  
Accessory Cell ◽  
Cancer Cell Survival

Metastatic breast cancer in bone is incurable and there is an urgent need to develop new therapeutic approaches to improve survival. Key to this is understanding the mechanisms governing cancer cell survival and growth in bone, which involves interplay between malignant and accessory cell types. Here, we performed a cellular and molecular comparison of the bone microenvironment in mouse models representing either metastatic indolence or growth, to identify mechanisms regulating cancer cell survival and fate. In vivo, we show that regardless of their fate, breast cancer cells in bone occupy niches rich in osteoblastic cells. As the number of osteoblasts in bone declines, so does the ability to sustain large numbers of breast cancer cells and support metastatic outgrowth. In vitro, osteoblasts protected breast cancer cells from death induced by cell stress and signaling via gap junctions was found to provide important juxtacrine protective mechanisms between osteoblasts and both MDA-MB-231 (TNBC) and MCF7 (ER+) breast cancer cells. Combined with mathematical modelling, these findings indicate that the fate of DTCs is not controlled through the association with specific vessel subtypes. Instead, numbers of osteoblasts dictate availability of protective niches which breast cancer cells can colonize prior to stimulation of metastatic outgrowth.

Synergy of nanodiamond-doxorubicin conjugates and PD-L1 blockade effectively turns tumor associated macrophages against tumor cells

2021 ◽  
Author(s):  
Huazhen Xu ◽  
Tongfei Li ◽  
Chao Wang ◽  
Yan Ma ◽  
Yan Liu ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Tumor Cell ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Lung Cancer Cells ◽  
Dependent Manner ◽  
Tumor Associated Macrophages ◽  
M1 Type

Abstract Background: Tumor-associated macrophages (TAM) are the most abundant stromal cells in the tumor microenvironment. Turning the TAM against their host tumor cells is an intriguing therapeutic strategy particularly attractive for patients with immunologically “cold” tumors. This concept was mechanistically demonstrated on in vitro human and murine lung cancer cells and their corresponding TAM models through combinatorial use of nanodiamond-doxorubicin conjugates (Nano-DOX) and a PD-L1 blocking agent BMS-1. Nano-DOX are an agent previously proved to be able to stimulate tumor cells’ immunogenicity and thereby reactivate the TAM into the anti-tumor M1 phenotype. Results: Nano-DOX were first shown to stimulate the tumor cells and the TAM to release the cytokine HMGB1 which, regardless of its source, acted through the RAGE/NF-κB pathway to induce PD-L1 in the tumor cells and PD-L1/PD-1 in the TAM. Interestingly, Nano-DOX also induced NF-κB-dependent RAGE expression in the tumor cells and thus reinforced HMGB1’s action thereon. Then, BMS-1 was shown to enhance Nano-DOX-stimulated M1-type activation of TAM both by blocking Nano-DOX-induced PD-L1 in the TAM and by blocking tumor cell PD-L1 ligation with TAM PD-1. The TAM with enhanced M1-type repolarization both killed the tumor cells and suppressed their growth. BMS-1 could also potentiate Nano-DOX’s action to suppress tumor cell growth via blocking of Nano-DOX-induced PD-L1 therein. Finally, Nano-DOX and BMS-1 achieved synergistic therapeutic efficacy against in vivo tumor grafts in a TAM-dependent manner. Conclusions: PD-L1/PD-1 upregulation mediated by autocrine and paracrine activation of the HMGB1/RAGE/NF-κB signaling is a key response of lung cancer cells and their TAM to stress, which can be induced by Nano-DOX. Blockade of Nano-DOX-induced PD-L1, both in the cancer cells and the TAM, achieves enhanced activation of TAM-mediated anti-tumor response.

Mouse prostate tumor inhibition via disruption of murine telomerase: In vivo and in vitro data for a new preclinical cancer model

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. e14631-e14631
Author(s):  
T. Xu ◽  
Y. Xu ◽  
R. Lao ◽  
K. He ◽  
L. Xue ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Dna Damage ◽  
Cancer Cells ◽  
Cancer Cell Line ◽  
Telomerase Activity ◽  
Telomerase Rna ◽  
Prostate Cancer Cells ◽  
Mouse Prostate

e14631 Background: Telomerase-interference (TI), a novel therapeutic strategy, exploits the high telomerase activity in prostate cancer by introducing a mutated telomerase RNA (MT-Ter) that encodes toxic telomeres. Until now, TI has been tested by targeting human telomerase in tumor cells xenografted into immuno-deficient mice, an inadequate model for predicting efficacy and toxicity. We designed and validated 2 new TI gene constructs that specifically target murine telomerase RNA (mTER), enabling the study of TI in preclinical mouse models that are immuno-competent and that develop endogenous prostate tumors. Methods: We designed 2 constructs and cloned them into a lentiviral delivery system: MT-mTER and siRNA against wild type mTer (α-mTer-siRNA). Using a mouse prostate cancer cell line, E4, we tested the 2 constructs for expression (RT-PCR), telomerase activity (TRAP), and biologic activity (53bp1 DNA damage staining, MTS growth assay, TUNEL and caspase apoptosis assays), as well as in vivo efficacy (NOD-SCID allografts). Results: We confirmed MT-mTER expression (∼50-fold) and showed that α-mTer-siRNA specifically depleted WT-mTER (80% reduction) but not MT-mTER when the 2 constructs are co-expressed; thus, the 2 constructs in combination effectively substituted MT-mTer for WT-mTer in the mouse prostate cancer cells. MT-mTER caused mutant telomeric repeats (TTTGGG instead of TTAGGG) to be added to the ends of telomeres, resulting in rapid telomeric uncapping marked by 53bp1 DNA damage foci (an average 7.5 foci/cell vs. 1.4 foci/cell in vector control). This, in turn, led to rapid and significant apoptosis (>90% TUNEL and caspase +) and growth inhibition in vitro (90% reduction by MTS) and in vivo (75% reduction in tumor allograft size). Conclusions: We successfully designed and validated MT-mTer and α-mTer-siRNA, 2 novel gene constructs that specifically target and co-opt murine telomerase activity within mouse prostate cancer cells. These constructs offer a significant advantage, as they can be used to investigate TI in immuno-competent mice that develop prostate cancer, thereby modeling actual human disease and testing TI-based therapies in a much more informative and authentic manner. No significant financial relationships to disclose.

scholarly journals Distribution and vulnerability of transcriptional outputs across the genome in Myc-amplified medulloblastoma cells

2021 ◽  
Author(s):  
Rui Yang ◽  
Wenzhe Wang ◽  
Meichen Dong ◽  
Kristen Roso ◽  
Paula Greer ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Tumor Cells ◽  
Target Genes ◽  
De Novo ◽  
Inhibitory Effect ◽  
Nucleotide Synthesis ◽  
High Level ◽  
The Impact

Myc plays a central role in tumorigenesis by orchestrating the expression of genes essential to numerous cellular processes1-4. While it is well established that Myc functions by binding to its target genes to regulate their transcription5, the distribution of the transcriptional output across the human genome in Myc-amplified cancer cells, and the susceptibility of such transcriptional outputs to therapeutic interferences remain to be fully elucidated. Here, we analyze the distribution of transcriptional outputs in Myc-amplified medulloblastoma (MB) cells by profiling nascent total RNAs within a temporal context. This profiling reveals that a major portion of transcriptional action in these cells was directed at the genes fundamental to cellular infrastructure, including rRNAs and particularly those in the mitochondrial genome (mtDNA). Notably, even when Myc protein was depleted by as much as 80%, the impact on transcriptional outputs across the genome was limited, with notable reduction mostly only in genes involved in ribosomal biosynthesis, genes residing in mtDNA or encoding mitochondria-localized proteins, and those encoding histones. In contrast to the limited direct impact of Myc depletion, we found that the global transcriptional outputs were highly dependent on the activity of Inosine Monophosphate Dehydrogenases (IMPDHs), rate limiting enzymes for de novo guanine nucleotide synthesis and whose expression in tumor cells was positively correlated with Myc expression. Blockage of IMPDHs attenuated the global transcriptional outputs with a particularly strong inhibitory effect on infrastructure genes, which was accompanied by the abrogation of MB cells proliferation in vitro and in vivo. Together, our findings reveal a real time action of Myc as a transcriptional factor in tumor cells, provide new insight into the pathogenic mechanism underlying Myc-driven tumorigenesis, and support IMPDHs as a therapeutic vulnerability in cancer cells empowered by a high level of Myc oncoprotein.

scholarly journals Repression of LKB1 by miR-17∼92 sensitizes MYC-dependent lymphoma to biguanide treatment

2019 ◽  
Author(s):  
Said Izreig ◽  
Alexandra Gariepy ◽  
Ariel O. Donayo ◽  
Gaëlle Bridon ◽  
Daina Avizonis ◽  
...  
Keyword(s):  
Cancer Cells ◽  
Tumor Cells ◽  
Human Cancer ◽  
Tca Cycle ◽  
Mirna Cluster ◽  
Lymphoma Cells ◽  
Ampk Signaling ◽  
Potential Biomarker

AbstractCancer cells display metabolic plasticity to survive metabolic and energetic stresses in the tumor microenvironment, prompting the need for tools to target tumor metabolism. Cellular adaptation to energetic stress is coordinated in part by signaling through the Liver Kinase B1 (LKB1)-AMP-activated protein kinase (AMPK) pathway. Reducing LKB1-AMPK signaling exposes metabolic vulnerabilities in tumor cells with potential for therapeutic targeting. Here we describe that miRNA-mediated silencing of LKB1 (mediated by the oncogenic miRNA cluster miR-17∼92) confers sensitivity of lymphoma cells to mitochondrial inhibition by biguanides. Using both classic (phenformin) and novel (IM156) biguanides, we demonstrate that Myc+ lymphoma cells with elevated miR-17∼92 expression display increased sensitivity to biguanide treatment both in cell viability assays in vitro and tumor growth assays in vivo. This increased biguanide sensitivity is driven by miR-17-dependent silencing of LKB1, which results in reduced AMPK activation in response to bioenergetic stress. Mechanistically, biguanide treatment inhibits TCA cycle metabolism and mitochondrial respiration in miR-17∼92-expressing tumor cells, targeting their metabolic vulnerability. Finally, we demonstrate a direct correlation between miR-17∼92 expression and biguanide sensitivity in human cancer cells. Our results identify miR-17∼92 expression as a potential biomarker for biguanide sensitivity in hematological malignancies and solid tumors.One Sentence SummarymiR-17∼92 expression in Myc+ tumors sensitizes cancer cells to biguanide treatment by disrupting bioenergetic stability in lymphoma cells.

scholarly journals Dual-Function Anti-CD47mAbs Induce Tumor Cell Death and Promote Phagocytosis Resulting in Enhanced in Vivo Efficacy

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 991-991
Author(s):  
Pamela T. Manning ◽  
Benjamin J. Capoccia ◽  
Michael P. Rettig ◽  
Ronald R. Hiebsch ◽  
Robert W. Karr ◽  
...  
Keyword(s):  
Cell Death ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Tumor Burden ◽  
Dual Function ◽  
Employment Equity ◽  
Hematologic Cancer ◽  
Equity Ownership

Abstract Recent success in immunomodulation of cancer has targeted immune checkpoints such as CTLA-4, PD-1 and PDL-1 to enhance adaptive immunity by stimulating production of tumor-selective, cytotoxic T cells. Anti-CD47mAbs enhance innate immunity by increasing the phagocytosis of tumor cells by macrophages leading to processing and presentation of tumor antigens to prime the adaptive T cell response. Many cancers, including hematologic cancers, up-regulate the expression of CD47 presumably to avoid immune destruction. Increased CD47 expression protects cancer cells from phagocytosis by sending a “don't eat me” signal to macrophages via SIRPalpha, an inhibitory receptor that prevents phagocytosis of CD47-bearing cells. CD47mAbs that block the CD47/SIRPalpha interaction (“blocking-only” mAbs) enhance phagocytosis of cancer cells in vitro. We have identified two CD47mAbs, Vx-1000 and Vx-1004, both of which block the CD47/SIRPalpha interaction and promote phagocytosis of tumor cells by macrophages equally well. However, Vx-1004 also has the unique property of killing cancer cells, but not normal blood cells, via a direct, cell-autonomous, cytotoxic mechanism. Therefore, Vx-1004 is a dual-function antibody. Vx-1004 selectively kills a variety of hematologic cancer cells in vitro, while Vx-1000, the blocking-only mAb, does not as assessed by annexin V staining and flow cytometry (Figure 1). In dose-response studies, cell death in leukemia cells was induced in 2 hrs by <1 ug="" vx-1004="" whereas="" normal="" peripheral="" blood="" mononuclear="" cells="" are="" resistant="" to="" the="" induction="" of="" cell="" death="" by="" following="" incubation="" with="" 10="" for="" 24="" hrs="" both="" these="" cd47mabs="" bind="" many="" species="" cd47="" including="" mouse="" and="" human="" p=""> To determine if the tumor-toxic activity of Vx-1004 confers enhanced efficacy in vivo compared to Vx-1000, we compared them in two mouse hematologic cancer models: murine acute promyelocytic leukemia (APL) and B cell lymphoma (BCL). Briefly, 1x106 GFP-labeled C57BL/6 APL cells were injected IV into wild-type C57BL/6 mice that were then treated IP with 0.4 mg/kg of either Vx-1000 or Vx-1004 on the day of tumor injection and on days 3 and 6 following tumor injection, a very low dose and limited dosing regimen. On day 25, the blood of these mice was analyzed for the number of circulating APL cells. As shown in Figure 2, Vx-1000 did not significantly reduce tumor burden compared to the control group. In contrast, Vx-1004 significantly reduced tumor burden compared to controls, demonstrating greater efficacy of the dual-function CD47mAb. In addition, enhanced efficacy of Vx-1004 compared to Vx-1000 was demonstrated in BCL (Figure 3). In this model, NSG mice were injected with 1x106 murine A20 lymphoma cells subcutaneously and then treated with 0.4mg/kg/day of the CD47mAbs IP for the first five days following tumor injection. In this model, Vx-1000 also failed to inhibit tumor growth compared to controls while Vx-1004 significantly reduced tumor burden at 35 days compared to both the control and Vx-1000 groups, nearly four weeks after treatment was stopped. These data demonstrate increased anti-cancer efficacy with a dual-function CD47mAb that not only blocks the CD47/SIRPalpha interaction to increase phagocytosis of cancer cells, but also selectively kills cancer cells. These studies indicate that dual-function CD47mAbs may have better anti-tumor activity in vivo and support their use in human clinical trials. Figure 1 Figure 1. Disclosures Manning: Corvus Pharmaceutical: Employment, Equity Ownership. Capoccia:Corvus Pharmaceutical: Employment, Equity Ownership. Hiebsch:Corvus Pharmaceutical: Employment, Equity Ownership. Karr:Corvus Pharmaceutical: Employment, Equity Ownership. Frazier:Corvus Pharmaceutical: Consultancy, Equity Ownership.

scholarly journals Enhanced Antisense Oligonucleotide Delivery Using Cationic Liposomes Grafted with Trastuzumab: A Proof-of-Concept Study in Prostate Cancer

Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1166
Author(s):  
Guillaume Sicard ◽  
Clément Paris ◽  
Sarah Giacometti ◽  
Anne Rodallec ◽  
Joseph Ciccolini ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Antisense Oligonucleotide ◽  
Therapeutic Option ◽  
Short Exposure ◽  
Castration Resistance ◽  
Prostate Cancer Cells ◽  
Model Free

Prostate cancer (PCa) is the second most common cancer in men worldwide and the fifth leading cause of death by cancer. The overexpression of TCTP protein plays an important role in castration resistance. Over the last decade, antisense technology has emerged as a rising strategy in oncology. Using antisense oligonucleotide (ASO) to silence TCTP protein is a promising therapeutic option—however, the pharmacokinetics of ASO does not always meet the requirements of proper delivery to the tumor site. In this context, developing drug delivery systems is an attractive strategy for improving the efficacy of ASO directed against TCTP. The liposome should protect and deliver ASO at the intracellular level in order to be effective. In addition, because prostate cancer cells express Her2, using an anti-Her2 targeting antibody will increase the affinity of the liposome for the cell and optimize the intratumoral penetration of the ASO, thus improving efficacy. Here, we have designed and developed pegylated liposomes and Her2-targeting immunoliposomes. Mean diameter was below 200 nm, thus ensuring proper enhanced permeation and retention (EPR) effect. Encapsulation rate for ASO was about 40%. Using human PC-3 prostate cancer cells as a canonical model, free ASO and ASO encapsulated into either liposomes or anti-Her2 immunoliposomes were tested for efficacy in vitro using 2D and 3D spheroid models. While the encapsulated forms of ASO were always more effective than free ASO, we observed differences in efficacy of encapsulated ASO. For short exposure times (i.e., 4 h) ASO liposomes (ASO-Li) were more effective than ASO-immunoliposomes (ASO-iLi). Conversely, for longer exposure times, ASO-iLi performed better than ASO-Li. This pilot study demonstrates that it is possible to encapsulate ASO into liposomes and to yield antiproliferative efficacy against PCa. Importantly, despite mild Her2 expression in this PC-3 model, using a surface mAb as targeting agent provides further efficacy, especially when exposure is longer. Overall, the development of third-generation ASO-iLi should help to take advantage of the expression of Her2 by prostate cancer cells in order to allow greater specificity of action in vivo and thus a gain in efficacy.

A CD19/CD3 Bispecific Tandab, AFM11, Recruits T Cells To Potently and Safely Kill CD19+ Tumor Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4405-4405
Author(s):  
Eugene Zhukovsky ◽  
Uwe Reusch ◽  
Carmen Burkhardt ◽  
Stefan Knackmuss ◽  
Ivica Fucek ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Cd8 T Cells ◽  
Cross Reactivity ◽  
Equity Ownership

Abstract To harness the potent tumor-killing capacity of T cells for the treatment of CD19+ malignancies, we developed a humanized bispecific tetravalent antibody, with two binding sites for CD3 and CD19, the CD19/CD3 RECRUIT-TandAb AFM11. CD19 is expressed from early B cell development through differentiation into plasma cells, and is an attractive alternative to CD20 as a target for the development of therapeutic antibodies to treat B cell malignancies such as Non Hodgkin Lymphoma. Since native antibodies cannot recruit T cells, we engineered a bispecific anti-CD19/anti-CD3 TandAb. The tumor-specific CD19 antigen module targets the TandAb to cancer cells, while simultaneously, the CD3 effector module recruits and activates T cells, leading to cancer cell lysis. The advantages of the TandAb technology, relative to other bi-functional fragment antibody scaffolds, include: improved pharmacokinetics (PK) enabling intravenous dosing, more drug-like properties, and avidity-enhanced efficacy for the targeting and killing of tumor cells. We evaluated in vitro efficacy and safety using CD19+ cell lines, and in vivo efficacy in a murine NOD/scid xenograft model reconstituted with human PBMC. Further, we used standard preclinical IND enabling assays to evaluate tissue cross reactivity, PK, and toxicological profile (local tolerance, hematocompatibility, effects on hematopoesis, etc). In vitro assays demonstrated the higher potency and efficacy of target cell lysis by AFM11 relative to a bispecific tandem scFv (that is currently in clinical evaluation). CD8+ T cells dominate early AFM11-mediated cytotoxicity (4 hrs) while after 24 hrs both CD4+ and CD8+ T cells equally contribute to tumor lysis with EC50 between 0.5 – 5 pM; cytotoxicity was independent of CD19 cell-surface density. AFM11 exhibited similar cytotoxicity over effector:target ratios ranging from 5:1 to 1:5, and facilitated serial T cell-killing of its targets. The advantage of AFM11 over the bispecific tandem scFv was most pronounced at lower effector:target ratios. AFM11 activated T cells only in the presence of CD19+ cells. In PBMC cultures, AFM11 induced CD69 and CD25 expression, T cell proliferation, and production of IFN-γ, TNF-α, IL-2, IL-6, and IL-10. Depletion of CD19+ cells from PBMC abrogated these effects, demonstrating that the T cell activation is strictly CD19+ target-dependent. Thus, AFM11 should not elicit the devastating cytokine release observed when full-length antibodies bind CD3. Up to one week co-incubation with AFM11 did not inhibit T cell cytotoxicity, suggesting that the TandAb does not induce anergy. In vivo, AFM11 induced dose-dependent growth inhibition of Raji tumors; a single 0.5 mg/kg dose exhibited efficacy similar to 5 daily injections. In the tissue cross reactivity study, only tissues containing CD19+ and CD3+ cells were stained by AFM11; all other tissues, including vital organs, displayed no cross reactivity. Similarly, no local intolerance was observed in rabbits, and no effect on myeloid and erythroid progenitors was observed in a colony-forming assay. Strong accumulation of 125I-labeled AFM11 was observed in the tumors of mice engrafted with CD19+ cancer cells, and no unspecific organ accumulation was observed. Finally, evaluated on the basis of Cmax and the area under the curve (AUC), AFM11 exhibited dose linearity (20 – 500 mg AFM11 dose range) upon single i.v. bolus administration in mice; half-life (T1/2) ranged from 18.4 to 22.9 hr. In summary, AFM11 is a highly efficacious novel drug candidate for the treatment of CD19+ malignancies with an advantageous safety profile and anticipated dosing regimen. Disclosures: Zhukovsky: Affimed Therapeutics AG: Employment, Equity Ownership. Reusch:Affimed Therapeutics AG: Employment. Burkhardt:Affimed Therapeutics AG: Employment. Knackmuss:Affimed Therapeutics AG: Employment. Fucek:Affimed Therapeutics AG: Employment. Eser:Affimed Therapeutics AG: Employment. McAleese:Affimed Therapeutics AG: Employment. Ellwanger:Affimed Therapeutics AG: Employment. Little:Affimed Therapeutics AG: Consultancy, Equity Ownership.

BMP4 signaling induces senescence and modulates the oncogenic phenotype of A549 lung adenocarcinoma cells

2004 ◽  
Vol 286 (1) ◽  
pp. L81-L86 ◽  
Author(s):  
S. Buckley ◽  
W. Shi ◽  
B. Driscoll ◽  
A. Ferrario ◽  
K. Anderson ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cancer Cells ◽  
Transforming Growth Factor ◽  
A549 Cells ◽  
Telomerase Activity ◽  
Lung Cancer Cells ◽  
Senescent Phenotype ◽  
A549 Lung

Lung cancer is the most common visceral malignancy in males, with rapidly increasing incidence in females, and a devastatingly poor prognosis. Transforming growth factor (TGF)-β has been shown to induce senescence in A549 lung cancer cells, and both TGF-β and bone morphogenetic protein (BMP) 2 can suppress the transformed phenotype of A549 cells in vitro. We examined the effects of BMP4, another member of the TGF-β superfamily, on specific oncogenic properties of A549 cancer cells. When A549 cancer cells were treated continuously with 100 ng/ml of BMP4, a senescent phenotype was observed after 2 wk of treatment. The BMP-treated cells appeared larger than untreated cells, grew more slowly, had more senescence-associated β-galactosidase activity, and had less telomerase activity, as measured by the telomeric repeat amplification protocol assay. Invasion through Engelbreth Holm-Swarm matrix was inhibited in the senescent cell population. Senescent BMP4-treated cells had lower ERK activation, VEGF expression, and Bcl2 expression than wild-type cells, consistent with a less proliferative, less angiogenic phenotype with increased susceptibility to death by apoptosis. BMP4 treatment also resulted in sustained elevation of Smad1. In vivo xenograft studies in the flanks of nude mice confirmed that the BMP-treated cells were significantly less tumorigenic than untreated cells. Direct overexpression of Smad1 using adenoviral constructs resulted in cell death within 5 days. These studies suggest that BMP4 pathway signaling can induce senescence and thus negatively regulate the growth of A549 lung cancer cells.

scholarly journals IMMU-55. GD2 IS A MACROPHAGE CHECKPOINT MOLECULE AND COMBINED GD2/CD47 BLOCKADE RESULTS IN SYNERGISTIC EFFECTS AGAINST GD2 POSITIVE MALIGNANCIES

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii116-ii116
Author(s):  
Johanna Theruvath ◽  
Christopher Mount ◽  
Michelle Monje ◽  
Crystal Mackall ◽  
Robbie Majzner
Keyword(s):  
Cancer Cells ◽  
Tumor Cells ◽  
Murine Model ◽  
Synergistic Effects ◽  
Preclinical Models ◽  
Metastatic Burden ◽  
Checkpoint Molecule ◽  
Biologic Basis

Abstract GD2 is a disialoganglioside expressed on a variety of tumors including DIPG, neuroblastoma and osteosarcoma. Anti-GD2 antibodies have demonstrated some success in neuroblastoma and they have either not proven to be effective or have not been evaluated in other GD2 positive malignancies. CD47 is the dominant “Don’t Eat Me” signal expressed by cancer cells to inhibit macrophages and blocking CD47 leads to phagocytosis of tumor cells. We hypothesized that CD47 blockade synergizes with anti-GD2. We measured in vitro phagocytosis of DIPG and NBL cells and observed a synergy of anti-GD2/CD47 compared to the single agents. In vivo, this combination led to the complete clearance of both orthotopic and metastatic models of NBL. Additionally, the combination significantly enhanced survival of OS xenografts. Finally, in a murine model of metastatic pulmonary OS, the combination led to a near elimination of all metastatic burden. To understand the underlying biologic basis, we studied the effects of GD2 crosslinking on tumor cells and the effects of GD2 blockade on macrophages. A portion of DIPG or NBL cells die when treated with dinutuximab, and those that survive upregulate surface calreticulin, an important pro-phagocytic (“Eat Me”) signal. Additionally, we have identified the ligand for GD2, a molecule expressed on macrophages known to inhibit phagocytosis. In summary, we have identified a novel combination of anti-GD2 and anti-CD47 antibodies that is highly effective in preclinical models and will soon be tested in children. Furthermore, we have shown that GD2 itself is a macrophage checkpoint or “Don’t Eat Me” signal.

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