Efficacy Of Camptothecin Research Articles

Ultrasound-Triggered Piezocatalysis for Selectively Controlled NO Gas and Chemodrug Release to Enhance Drug Penetration in Pancreatic Cancer.

Nitric oxide (NO) is drawing widespread attention in treating pancreatic ductal adenocarcinoma (PDAC) as a safe and therapeutically efficient technique through modulating the dense fibrotic stroma in the tumor microenvironment to enhance drug penetration. Considerable NO nanogenerators and NO releasing molecules have been developed to shield the systemic toxicity caused by free diffusion of NO gas. However, on-demand controlled release of NO and chemotherapy drugs at tumor sites remains a problem limited by the complex and dynamic tumor microenvironment. Herein, we present an ultrasound-responsive nanoprodrug of CPT-t-R-PEG2000@BaTiO3 (CRB) which encapsulates piezoelectric nanomaterials barium titanate nanoparticle (BaTiO3) with amphiphilic prodrug molecules that consisted of thioketal bond (t) linked chemotherapy drug camptothecin (CPT) and NO-donor l-arginine (R). Based on ultrasound-triggered piezocatalysis, BaTiO3 can continuously generate ROS in the hypoxic tumor environment, which induces a cascade of reaction processes to break the thioketal bond to release CPT and oxidize R to release NO, simultaneously delivering CPT and NO to the tumor site. It is revealed that CRB shows a uniform size distribution, prolonged blood circulation time, and excellent tumor targeting ability. Moreover, controlled release of CPT and NO were observed both in vitro and in vivo under the stimulation of ultrasound, which is beneficial to the depletion of dense stroma and subsequently enhanced delivery and efficacy of CPT. Taken together, CRB significantly increased the antitumor efficacy against highly malignant Panc02 tumors in mice through inhibiting chemoresistance, representing a feasible approach for targeted therapies against Panc02 and other PDAC.

Transcription Factor Fli-1 Regulates T Cell Immunity and Tolerance in Gvh and GVL Responses

The E26 transformation-specific (ETS) transcription factor (TF) family member Friend Leukemia Virus Integration 1 (Fli-1) is linked to the oncogenesis of virally induced leukemia and Ewing's Sarcoma, as well as the development of autoimmune diseases including systemic lupus erythematosus and systemic sclerosis. A recent report presents compelling evidence that Fli-1 restrains CD8 effector T cell differentiation and protective immunity against cancer. How Fli-1 regulates primary T cell differentiation and function remain largely elusive. In this study, we investigated the role of Fli-1 in T-cell pathogenicity of graft-versus-host disease (GVHD) and validated Fli-1 as a therapeutic target. Using conditional knock-out models featured as homozygous (Fli-1KO) or heterozygous (Fli-1HET) deficiency of Fli-1 in T cells, we found that Fli-1 dynamically regulates different T-cell subsets in allogeneic responses and pathogenicity in the development of acute and chronic GVHD. Compared to Fli-1KO or Fli-1WT T cells, Fli-1HET T cells induced the mildest aGVHD and cGVHD supported by lowest Th1 and Th17 differentiation (Fig. 1 A-B). In addition, Fli-1HET T cells were able to maintain a strong graft-versus-leukemia (GVL) effect while inducing significantly attenuated GVHD. Fli-1-deficient CD8+ T cells expressed comparable levels of cytolytic molecules, reduced levels of exhaustion markers, and differentiated more into memory precursor effector cells compared to WT CD8 T cells after been transferred into allogeneic recipients. To further understand how Fli-1 regulates T-cell gene transcription and heterogeneity, we performed scRNA seq analysis of donor T cells, including Fli-1WT, Fli-1HET and Fli-1KO, isolated from recipient spleens. The scRNA seq analysis on the donor T cells indicated a major difference in the transcriptional regulation by Fli-1 in CD4 versus CD8 T cells and Fli-1 gene dose dependent modification in transcriptional pathways in Fli-1Het vs Fli-1KOT cells. Fli-1 deemed to play a distinct role in regulating gene transcription in CD4 versus CD8 T cells, in that more activation and less exhaustion gene pathways were enriched in CD8 Fli-1 deficient cells, while fewer genes in Th1/Th17 pathogenic pathways were enriched in CD4 Fli-1 deficient cells (Fig. 1 C-D). Overall, Fli-1 deficiency increased gene enrichment in OXPHOS pathway in both CD4 and CD8 T cells, and reduced gene enrichment in glycolysis pathway majorly in CD4 T cells (Fig. 1 E-F). Consistent with the lowest pathogenicity of Fli-1Het T cells for GVHD induction, Fli-1Het CD4 T cells had the lowest Th1/Th17 pathway gene enrichment and TCR pathway downstream gene expression. Camptothecin, topotecan or etoposide exhibited action as potent Fli-1 inhibitors at low-doses. For translational purpose, we tested these drugs and found that each of these drugs significantly attenuated GVHD severity while preserving the GVL effect. The efficacy of camptothecin or etoposide at low doses was dependent of Fli-1 expression on donor T cells. Mechanistically, blocking Fli-1 suppressed activated effector T cells while sparing Tregs and had no side effect on hematopoietic stem cells. Importantly, using the same treatment schedule as post-transplantation cyclophosphamide (PTCy), two doses of camptothecin or etoposide administered on day 3 and 4 were sufficient for the prevention of GVHD and leukemia relapse, in contrast to GVHD mortality in some of those treated with bendamustine and leukemia relapse in some of those treated with PTCy or cyclosporine (Fig. 1 G-I). In addition, the beneficial effect of camptothecin was extended in GVHD induced by human T cells in a xenograft model. In conclusion, we provide the first evidence that Fli-1 plays a crucial role in alloreactive CD4 T-cell activation and differentiation, and that targeting Fli-1 may be an attractive strategy for treating GVHD without compromising GVL effect. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Designed poly(ethylene glycol) conjugate-erbium-doped magnetic nanoparticle hybrid carrier: enhanced activity of anticancer drug

Magnetic drug carriers are aimed at transporting the loaded drugs to the target site with the application of an external field. To realize this, a clever design of magnetic nanoparticles and their surface modification have to be achieved. Herein, we report the synthesis of ErFeO3 nanoparticles and their magnetic characteristics. In addition, we report a β-cyclodextrin-polyethylene glycol-folate conjugate and utilize it for coating the magnetic nanoparticles. The crystallinity and grain size of the nanoparticles are characterized using X-ray diffraction. The elemental composition of the nanoparticles and their orbital states are determined using XPS spectroscopy. The polymer-coated nanoparticles are soft ferromagnetic. The anticancer drug, camptothecin, is loaded on the polymer-coated nanoparticles with a loading percentage of about 88%. The efficacy of camptothecin gets enhanced when loaded on the magnetic nanocarrier and released in a sustained manner. Compared to the free form, the drug loaded on the nanocarrier shows an enhanced anticancer activity.

Preclinical to clinical development of the novel camptothecin nanopharmaceutical CRLX101

Camptothecin (CPT) is a potent broad-spectrum anticancer agent that acts through inhibition of topoisomerase 1. Clinical development of CPT was unsuccessful due to poor drug solubility, insufficient in vivo stability of the active form, and toxicity. In order to address these issues, a polymeric nanoparticle comprised of cyclodextrin-poly(ethylene glycol) copolymer (CDP) conjugated to CPT (CRLX101) has been developed and Phase 2 clinical studies are ongoing. Camptothecin is conjugated to the polymer in its active form at 10–12wt.% loading. CRLX101 self-assembles in solution into nanoparticles with an apparent solubility increase of >1000-fold as compared to the parent drug camptothecin. Preclinical studies exhibited CRLX101 pharmacokinetics superior to the parent drug. Drug concentration in tumor relative to plasma and other major organs is consistent with the enhanced permeation and retention (EPR) anticipated from a nanoparticle. Significant anti-tumor activity was observed that is superior when compared to irinotecan across a broad range of xenograft models. Pharmacokinetic data are consistent with the prolonged half-life and increased AUC. The CRLX101 preclinical and clinical data confirm that CDP can address not only solubility, formulation, toxicity, and pharmacokinetic challenges associated with administration of CPT, but more importantly, can impart unique biological properties, that enhance pharmacodynamics and efficacy of camptothecin.

Genomic analyses identify gene candidates for acquired irinotecan resistance in melanoma cells

Efficacy of camptothecins (CPTs) such as irinotecan has been recognized in chemotherapy of cancers including melanoma. However, the majority of responding patients will gradually acquire drug resistance. Little is known of the genes responsible for the acquired CPT-resistance in cancer. To gain global insight into acquired CPT-resistance, we established irinotecan-resistant clones derived from melanoma cells and compared their whole genomes by high resolution array-CGH. A novel gain at 14q23.2-31.1 was revealed by alignment of whole genome profiles of parental cell line and irinotecan-resistant clones. Further analysis of this amplicon indicates that it encompassed genes involved in DNA repair (RAD51L, MLH3), reactive oxygen species (GPX2, CSTZ1, NGB, RDH11, ZADH1), and transportome (ABCD4, ATP6V1D, SLC10A6). Moreover, losses were also detected at the loci of topoisomerases (TOP1, SPO11, TOP3B) as well as at the loci of genes guarding chromosomal stability (TP53, ZW10, H2AFX, CHK1, CCDN1, MCM5, CENPB, DNMT3B), which would facilitate the development of drug resistance. Furthermore, quantitative real-time PCR demonstrated that mRNA changes of selected novel genes (CENPB, H2AFX, MCM5, ZADH1 and NGB) in irinotecan-resistant clones vs. parental clone were in agreement with array-CGH results. Taken together, our data suggest that genes involved in genome stability may greatly contribute to the development of CPTs-resistance. In addition, genes located at 14q23.3-31.1 would be promising targets to overcome acquired CPT-resistance in melanoma.

Efficacy of camptothecin and polymer-conjugated camptothecin in tumor spheroids and solid tumors

Camptothecin (CPT) is an anti-cancer drug with low solubility in aqueous solutions, which limits its efficacy during chemotherapy. To bypass this problem, CPT was conjugated to poly(ethylene glycol) (PEG) to make CPT more hydrophilic: CM-PEG-CPT (carboxylmethylpoly(ethlyene glycol)-camptothecin), CM-PEG-GLY-CPT (carboxylmethyl-poly(ethlyene glycol)-glycine-camptothecin) and CM-PEG-SAR-CPT (carboxylmethyl-poly(ethlyene glycol)-sarcosine camptothecin) were synthesized. These conjugates differed in the amino-acid linker, which altered the hydrolysis rate of CPT from CPT-PEG. We tested the hypothesis that CPT conjugates were more effective than unconjugated CPT in effectiveness upon direct delivery to solid tumors using two systems: in vitro tumor spheroids suspended in collagen gels and in vivo solid tumors in rats. CPT was effective in spheroids, but not in flank tumors. However, when CPT was conjugated, there was improvement in the treatment of spheroids and, to a lesser extent, tumors in rats. There was no difference in therapeutic effects among the various conjugates. We conclude that conjugation of CPT to PEG enhances CPT solubility and improves effectiveness of delivery to tumors.

Circadian regulation of mouse topoisomerase I gene expression by glucocorticoid hormones

Because glucocorticoid hormones modulate various biological processes, the endogenous rhythm of their secretion is thought to be an important factor affecting the efficacy and/or toxicity of many drugs. Topoisomerase I (Topo I) is a nuclear target of the anticancer drug camptothecin (CPT). In this study, we demonstrate that Topo I expression in tumor-bearing mice and the efficacy of CPT on the tumor are affected by the 24-h variation in circulating glucocorticoid levels. A single administration of corticosterone (CORT) to the tumor-bearing mice resulted in a significant increase in Topo I mRNA levels not only in the tumor masses but also in other healthy tissues such as liver and skeletal muscle. The CORT-induced increase in Topo I mRNA was suppressed by pretreating the mice with RU486, a glucocorticoid receptor antagonist. Significant 24-h oscillations in the Topo I mRNA levels were observed in the tumor and healthy liver without exogenous CORT, and were eliminated by adrenalectomy of the mice. This result suggests that endogenous glucocorticoid hormones are involved in the circadian regulation of Topo I gene expression. Furthermore, the anti-tumor efficacy of the Topo I inhibitor CPT-11 on the tumor-bearing mice was enhanced by administering the drug at the time when the Topo I activity was increased. Our present results demonstrate that glucocorticoid is involved in the 24-h oscillation mechanism of Topo I gene expression and suggest that monitoring the circadian rhythm in Topo I activity is useful for choosing the most appropriate time of day to administer of Topo I inhibitors.

Polymer delivery of camptothecin against 9L gliosarcoma: release, distribution, and efficacy.

Camptothecin is a potent antineoplastic agent that has shown efficacy against multiple tumor lines in vitro; unfortunately, systemic toxicity has limited its in vivo efficacy. This is the first study to investigate the release, biodistribution, and efficacy of camptothecin from a biodegradable polyanhydride polymer. Tritiated camptothecin was incorporated into biodegradable polymers that were implanted intracranially in 16 male Fischer 344 rats and the animals were followed up to 21 days post-implant. A concentration of 11-45 microg of camptothecin-sodium/mg brain tissue was within a 3 mm radius of the polymer disc, with levels of 0.1 microg at the outermost margin of the rat brain, 7 mm from the site of implantation. These tissue concentrations are within the therapeutic ranges for human and rat glioma lines tested against camptothecin-sodium in vitro. The in vivo efficacy of camptothecin-sodium was evaluated with male Fischer 344 rats implanted intracranially with 9L gliosarcoma and compared with the efficacy of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU). The animals were divided into four groups. Group 1 (control) had a median survival of 17 days. Group 2 (3.8% BCNU polymer) had a median survival of 23 days (P = 0.006). Group 3 (20% camptothecin polymer) had a median survival of 25 days (P = 0.023). Group 4 (50% camptothecin polymer) had a median survival of 69 days (P < 0.001). Drug loadings of 20% and 50% camptothecin released intact camptothecin for up to 1000 h in vitro. We conclude that the biodegradable polymer p(CPP: SA) releases camptothecin-sodium, produces tumoricidal tissue levels, results in little or no systemic toxicity, and prolongs survival in a rat glioma model.

Genomic analyses identify gene candidates for acquired irinotecan resistance in melanoma cells

Efficacy of camptothecins (CPTs) such as irinotecan has been recognized in chemotherapy of cancers including melanoma. However, the majority of responding patients will gradually acquire drug resistance. Little is known of the genes responsible for the acquired CPT-resistance in cancer. To gain global insight into acquired CPT-resistance, we established irinotecan-resistant clones derived from melanoma cells and compared their whole genomes by high resolution array-CGH. A novel gain at 14q23.2-31.1 was revealed by alignment of whole genome profiles of parental cell line and irinotecan-resistant clones. Further analysis of this amplicon indicates that it encompassed genes involved in DNA repair (RAD51L, MLH3), reactive oxygen species (GPX2, CSTZ1, NGB, RDH11, ZADH1), and transportome (ABCD4, ATP6V1D, SLC10A6). Moreover, losses were also detected at the loci of topoisomerases (TOP1, SPO11, TOP3B) as well as at the loci of genes guarding chromosomal stability (TP53, ZW10, H2AFX, CHK1, CCDN1, MCM5, CENPB, DNMT3B), which would facilitate the development of drug resistance. Furthermore, quantitative real-time PCR demonstrated that mRNA changes of selected novel genes (CENPB, H2AFX, MCM5, ZADH1 and NGB) in irinotecan-resistant clones vs. parental clone were in agreement with array-CGH results. Taken together, our data suggest that genes involved in genome stability may greatly contribute to the development of CPTs-resistance. In addition, genes located at 14q23.3-31.1 would be promising targets to overcome acquired CPT-resistance in melanoma.