Growth Of Cancer Cells In Mice Research Articles

A novel CD47-blocking peptide fused to pro-apoptotic KLA repeat inhibits lung cancer growth in mice.

CD47 is highly expressed in many tumor tissues and induces immune evasion by interaction with SIRP-alpha (signal regulatory protein-alpha) expressed on tumor-associated macrophages. In this study, we identified a novel CD47-blocking peptide VK17 by phage display technique. A pro-apoptotic VK30 peptide was obtained after VK17 was fused to KLA amino acid repeat at C-termini. The VK30 was specifically bound to CD47 on lung cancer cells, and subsequently inducing lung cancer cell apoptosis. Meanwhile, the expression of Bax was increased, whereas the expression of Bcl-2 and Ki-67 were reduced in the VK30-treated lung cancer cells. In addition, VK30 effectively improved the phagocytic activity of macrophages against VK30-pretreated lung cancer cells. Combinational treatment of lung cancer cells with blocking antibody anti-CD47 and VK30 additively enhanced VK30 binding to CD47, subsequently increasing lung cancer cell apoptosis and macrophage phagocytosis. Intraperitoneal administration of 2mg/kg VK30 induced effective trafficking of VK30 into tumor tissues, and suppressing lung cancer cell growth in mice, associated with increased tumor cell apoptosis, macrophage activation and phagocytosis in vivo. The expression of CD47 was reduced in the VK30-treated tumor tissues and the expression level was positively correlated to tumor size. In addition, VK30 reduced the infiltration of CD11b+Ly6G+ neutrophils and CD11b+Ly6C+Ly6G+ granulocytic myeloid-derived suppressor cells (Gr-MDSCs) in tumor tissues, associated with suppressed expression of tumorigenic IL-6 and TNF-alpha from these cell types. Thereby, VK30 exerted anti-tumor effects in mice through inducing tumor cell apoptosis and macrophage phagocytosis. VK30 would be a novel therapeutic peptide in lung cancer immunotherapy.

Lack of SIRP-alpha reduces lung cancer growth in mice by promoting anti-tumour ability of macrophages and neutrophils.

Signal regulatory protein-alpha (SIRPα) is a transmembrane glycoprotein specifically expressed on myeloid cells. Blockade of SIRPα/CD47 interaction is effective in combinational therapy of some cancers. This study aimed to explore into the role and underlying molecular mechanisms of SIRPα in lung cancer growth. A mouse model with lung cancer in wild-type (WT) and SIRPα-knockout mouse (KO) mice was established by subcutaneous injection of Lewis murine lung cancer cells (LLC). Circulating monocytes and neutrophils were depleted in mice by intraperitoneal administration of clodronate liposomes and anti-Ly6G antibody, respectively. Phenotypes and phagocytosis of macrophages and neutrophils were analysed by flow cytometry. Transwell assay was used to analyse LLC cells migration and invasion. Lack of SIRPα inhibited LLC cells growth in KO mice, associated with reduced infiltrating PD-1+ CD8+ T cells and production of IL-6 from infiltrating macrophages and neutrophils in tumour tissues. Depletion of circulating monocytes and neutrophils reduced LLC cells growth in WT mice, which was abolished in KO mice. Studies in vitro showed that lack of SIRPα increased M1/M2 ratio, and reduced LLC cell migration and invasion via attenuated IL-6 secretion. Lack of SIRPα expression in neutrophils effectively increased the cytotoxic activity to LLC cells in vitro. Lack of SIRPα suppressed lung cancer cell growth in mice, dependent on circulating macrophages and neutrophils, in association with improved phagocytosis and reduced IL-6 expression.

Rutaecarpine administration inhibits cancer cell growth in allogenic TRAMP-C1 prostate cancer mice correlating with immune balance in vivo

BackgroundRutaecarpine (Rut) is a plant alkaloid abundant in Euodia ruticarpa which is a Chinese herbal medicine used for treating various cancers. However, the Rut administration effect on prostate cancer in vivo remains unclear. AimIn the present study we established an allogenic TRAMP-C1 prostate cancer mouse model to evaluate the Rut administration effect and mechanism in vivo. MethodsTo unravel the Rut administration effect on prostate cancer in vivo, C57BL/6J male mice (8 weeks old) were randomly grouped (n = 9), subcutaneously loaded with TRAMP-C1 prostate cancer cells and immediately given daily by gavage with Rut dissolved in soybean oil at 7 mg (low dose), 35 mg (medium dose), and 70 mg/kg b.w./day (high dose) for successive 39 days. ResultsRut administration significantly and dose-dependently reduced both tumor volume and solid prostate cancer weight in allogenic TRAMP-C1 male mice. Rut administration markedly increased (TNF-α+IFN-γ) (Th1-)/IL-10 (Th2-) cytokine secretion ratios by splenocytes and TNF-α (M1-)/IL-10 (M2-) cytokine secretion ratios by macrophages as compared to those of dietary control group, suggesting that Rut administration in vivo regulates the immune balance toward Th1- and M1-polarized characteristics. Decreased CD19+, CD4+ and CD8+ lymphocytes in the peripheral blood of allogenic TRAMP-C1 mice were significantly elevated by Rut administration. Tumor weights positively correlated with TNF-α secretions by splenocytes, suggesting that there is a tumor cachexia in the tumor-bearing mice. Tumor weights negatively correlated with IgG (Th1-antibody) levels in the sera, suggesting that Th1-polarized immune balance may inhibit prostate cancer cell growth. ConclusionsOur results evidenced that Rut administration suppresses prostate cancer cell growth in mice subcutaneously loaded with TRAMP-C1 cells and correlated the anti-cancer effects with Th1-polarized immune balance in vivo.

Treatment with a New Barbituric Acid Derivative Exerts Antiproliferative and Antimigratory Effects against Sorafenib Resistance in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a common cause of cancer death worldwide. Sorafenib, a multikinase inhibitor, is the first-line drug approved by the Food and Drug Administration (FDA) for the treatment of patients with advanced HCC. However, most patients who continuously receive sorafenib may acquire resistance to this drug. Therefore, it is important to develop a new compound to treat liver cancer and sorafenib-resistant liver cancer. Barbituric acid derivatives have been used as antiasthmatic drugs in the clinic. We previously reported that a novel barbituric acid derivative inhibited carbon tetrachloride-induced liver fibrosis in mice, but its effects on liver cancer remain unknown. Thus, the purpose of this study was to investigate the antitumor effect of barbituric acid derivatives on HCC cells and sorafenib-resistant HCC cells (HCC-SRs). Our findings reveal that one of the barbituric acid derivatives, BA-5, significantly inhibited HCC and HCC-SR cell viability in a dose- and time-dependent manner. Therefore, compound BA-5 was selected for further experiments. Western blot data revealed that BA-5 treatment decreased the phosphorylation of AKT/p70s6k without affecting the MAPK pathway and increased cleaved PARP and cleaved caspase-7 in both HCC and HCC-SR cells. Since epithelial-mesenchymal transition plays a significant role in regulating cancer invasion and migration, we used the wound healing assay to evaluate the antimigratory effect of compound BA-5. The results showed that BA-5 treatment inhibited HCC and HCC-SR cell migration and reduced Vimentin protein expression. These results were confirmed by microarray analysis showing that BA-5 treatment influenced cancer cell motility and growth-related pathways. In the xenograft mouse model experiment, BA-5 administration significantly inhibited HCC cancer cell growth in mice. Furthermore, the combination of BA-5 with a low dose of regorafenib synergistically inhibited HCC-SR cell proliferation. In conclusion, our study showed that the barbituric acid derivative BA-5 is a new candidate for HCC and sorafenib-resistant HCC therapy.

IL33 activates CD8+T and NK cells through MyD88 pathway to suppress the lung cancer cell growth in mice.

In this study, we observed the effects of IL-33 on tumor immune response in lung cancer-bearing mice using wild type and MyD88-/- mice respectively. Wild C57BL/6 (C57BL/6WT), MyD88 knockout C57BL/6 mice (C57BL/6 MyD88-/-) and Lewis cells were used in this study. Cell proliferation, cytokine release and cytotoxicity were detected. IL-33 could significantly up-regulate specific cellular immunity, inhibit tumor growth and improve survival time in wild type mice group, and it had dose dependent effect. However, IL-33 had no effect on cell immunity and tumor growth in MyD88-/- mice group. Compared with MyD88-/- mice, IL-33 could significantly increase the ratio of CD8+T cells to neutrophils in wild type mice, while the percentage of tumor infiltrating CD11b+ cells, Mo-MDSC, F4/80+ macrophages and mDC cells decreased significantly in wild type mice group. IL-33 could upregulate the expression of CD107a and IFN-γ in CD8+T cells and NK cells of wild type mice, while IL-33 could not upregulate them in MyD88-/- mice. IL-33 could upregulate the expression of CD40, CD80, CD86 and CD205 in DC cells in wild type mice, induce T cells to differentiate into Th1 cells and enhance tumor cell immunity. IL-33 could promote differentiation and maturation of DC cells through MyD88 pathway, up-regulate the tumor immunity of CD8+T cells and NK cells, and inhibit the proliferation of lung cancer cells.

HMGCS2 Mediates Ketone Production and Regulates the Proliferation and Metastasis of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the most common primary malignant tumor worldwide; however, the traditional therapeutic approaches and survival rates are still limited. To improve current therapies, it is necessary to investigate the molecular mechanisms underlying liver cancer and to identify potential therapeutic targets. The aims of this study were to verify the mechanisms and therapeutic potential of the ketogenesis rate-limiting enzyme 3-Hydroxymethylglutaryl-CoA synthase 2 (HMGCS2) in HCC. Immunohistochemical staining of human liver disease tissue arrays showed that HMGCS2 is abundantly expressed in normal liver tissues but is downregulated in cirrhosis and HCC tissues. In HCC patients, lower HMGCS2 expression was correlated with higher pathological grades and clinical stages. In our investigation of the molecular mechanisms of HMGCS2 in HCC, we showed that knockdown of HMGCS2 decreased ketone production, which promoted cell proliferation, cell migration, and xenograft tumorigenesis by enhancing c-Myc/cyclinD1 and EMT signaling and by suppressing the caspase-dependent apoptosis pathway. Ketone body treatment reduced the proliferation- and migration-promoting effects of HMGCS2 knockdown in cells. In contrast, HMGCS2 overexpression increased the intracellular ketone level and inhibited cell proliferation, cell migration, and xenograft tumorigenesis. Finally, ketogenic diet administration significantly inhibited liver cancer cell growth in mice. Our studies highlight the potential therapeutic strategy of targeting HMGCS2-mediated ketogenesis in liver cancer.

Transcription Factor MafB Promotes Hepatocellular Carcinoma Cell Proliferation through Up-Regulation of Cyclin D1

Background/Aims: MafB, a member of the Maf transcription factor family, plays a key role in the regulation of pancreatic alpha and beta cell differentiation. However, its function in the control of cancer cell proliferation remains unknown. Methods: The mRNA and protein expression levels of MafB in hepatocellular carcinoma tissues and adjacent non-tumor normal specimens were determined by real-time RT-PCR and Western blot, respectively. Report assay was performed to determine whether the regulation of Cyclin D1 by MafB is at the transcriptional level. The binding of MafB to the Cyclin D1 promoter was determined by Chromatin Immunoprecipitation (ChIP) assays. To determine the potential oncogenic effects of MafB in vivo, HepG2 cells transfected with adenovirus containing empty vector or MafB were injected subcutaneously to the skin under the front legs of the nude mice. Results: In the current study, we showed that MafB was markedly up-regulated in hepatocellular carcinoma (HCC) tissues and cells. Enforced overexpression of MafB enhanced, while its deficiency inhibited HCC cell proliferation. Mechanistically, Cyclin D1, an important regulator of cell cycle progression, was identified as a direct transcriptional target of MafB. Consistently, knockdown of Cyclin D1 largely attenuated the proliferative roles of MafB in HCC cells. Importantly, MafB overexpression significantly promoted cancer cell growth in mice. Conclusions: Collectively, our results identified a novel HCC regulatory pathway involving MafB and Cyclin D1, the dysfunction of which drives proliferative character in HCC.

Myxomaviral Anti-Inflammatory Serpin Reduces Myeloid-Derived Suppressor Cells and Human Pancreatic Cancer Cell Growth in Mice.

Modification of the tumor microenvironment by inflammatory cells represents a newly recognized driving force in cancer with critical roles in tumor invasion, growth, angiogenesis, and metastasis. Increased thrombolytic cascade serine proteases, specifically urokinase-type plasminogen activator and its receptor, correlate with inflammatory cell migration, pancreatic cancer growth, invasion and unfavorable outcomes. Inflammation in pancreatic cancer is linked with myeloid-derived suppressor cell (MDSC) activity and cancer progression. Myxomavirus is a complex DNA virus encoding highly potent immune modulators. Serp-1 and M-T7 are two such secreted anti-inflammatory myxomaviral proteins. Serp-1 inhibits uPA, plasmin and coagulation factor X while M-T7 inhibits C, CC, and CXC chemokines. We have explored the potential use of these viral proteins for treatment of a range of human cancer isolates engrafted in severe combined immunodeficient (SCID) mice. Engrafted tumors were treated with either Serp-1, neuroserpin, a related mammalian serpin that inhibits thrombolytic proteases, or M-T7. Serp-1 and neuroserpin inhibited growth of the pancreatic cancer cell line Hs766t (P=0.03 and P=0.01, respectively) at 4 weeks after implantation. Serp-1 also inhibited growth of a second pancreatic cancer cell line MIA PaCa-2 in mice (P=0.02). Growth of the human breast cancer line MDA231 was not inhibited by Serp-1. M-T7, in contrast, did not alter growth of any of the cancer cell lines tested after implant into SCID mice. Serpin inhibition of pancreatic tumor growth was associated with a significant decrease in splenocyte MDSC counts by flow cytometry (P=0.009), without detected change in other splenocyte subpopulations. Serp-1 and NSP treatment also significantly reduced macrophage infiltration in tumors (P=0.001). In summary two anti-inflammatory serpins reduced inflammatory macrophage invasion and pancreatic tumor cell growth, suggesting potential therapeutic efficacy.

Reprogramming Murine Telomerase Rapidly Inhibits the Growth of Mouse Cancer Cells In vitro and In vivo

Telomerase plays a critical role in cancer, prompting the pursuit of various telomerase-based therapeutic strategies. One such strategy, telomerase interference, exploits the high telomerase activity in cancer cells and reprograms telomerase to encode "toxic" telomeres. To date, telomerase interference has been tested in human cancer cells xenografted into mice, an approach that does not recapitulate spontaneous malignancy and offers few insights about host toxicities, because human telomerase is targeted in a mouse host. To address these limitations, we designed and validated two new gene constructs specifically targeting mouse telomerase: mutant template mouse telomerase RNA (MT-mTer) and small interfering RNA against wild-type mouse telomerase RNA (α-mTer-siRNA). Using lentiviral delivery in mouse prostate cancer cells, we achieved α-mTer-siRNA-mediated knockdown of wild-type mTer (80% depletion) and concurrent overexpression of MT-mTer (50-fold). We showed that the two constructs effectively synergize to reprogram murine telomerase to add mutant instead of wild-type telomeric repeats, resulting in rapid telomeric uncapping (5-fold increase in DNA damage foci). This, in turn, led to rapid and significant apoptosis (>90% of cells) and growth inhibition in vitro (90% reduction in viable cell mass) and in vivo (75% reduction in tumor allograft wet weight). In summary, we have shown that mouse cancer cells are vulnerable to direct telomerase interference using novel murine telomerase-targeting constructs; this approach can now be used to study the true therapeutic potential of telomerase interference in mouse spontaneous cancer models.

Pharmacogenomics and analogues of the antitumour agent N6‐isopentenyladenosine

N(6)-isopentenyladenosine (i(6)A), a member of the cytokinin family of plant hormones, has potent in vitro antitumour activity in different types of human epithelial cancer cell lines. Gene expression profile analysis of i(6)A-treated cells revealed induction of genes (e.g., PPP1R15A, DNAJB9, DDIT3, and HBP1) involved in the negative regulation of cell cycle progression and reportedly up-regulated during cell cycle arrest in stress conditions. Of 6 i(6)A analogues synthesized, only the 1 with a saturated double bond of the isopentenyl side chain had in vitro antitumour activity, although weaker than that of i(6)A, suggesting that i(6)A biological activity is highly linked to its structure. In vivo analysis of i(6)A and the active analogue revealed no significant inhibition of cancer cell growth in mice by either reagent. Thus, although i(6)A may inhibit cell proliferation by regulating the cell cycle, further studies are needed to identify active analogues potentially useful in vivo.