Targeting Tn-Antigen-Positive Human Tumors with a Recombinant Human Macrophage Galactose C-Type Lectin.

Alterations in glycosylation cause the emergence of tumor-associated carbohydrate antigens (TACAs) during tumorigenesis. Truncation of O-glycans reveals the Thomsen nouveau (Tn) antigen, an N-acetylgalactosamine (GalNAc) frequently attached to serine or threonine amino acids, that is accessible on the surface of cancer cells but not on healthy cells. Interestingly, GalNac can be recognized by macrophage galactose lectin (MGL), a type C lectin receptor expressed in immune cells. In this study, recombinant MGL fragments were tested in vitro for their cancer cell-targeting efficiency by flow cytometry and confocal microscopy and in vivo after administration of fluorescent MGL to tumor-bearing mice. Our results demonstrate the ability of MGL to target Tn-positive human tumors without inducing toxicity. This outcome makes MGL, a fragment of a normal human protein, the first vector candidate for in vivo diagnosis and imaging of human tumors and, possibly, for therapeutic applications.

Stapled peptide targeting the CDK4/Cyclin D interface combined with Abemaciclib inhibits KRAS mutant lung cancer growth.

CDK4/cyclin D kinase constitutes an attractive pharmacological target for development of anticancer therapeutics, in particular in KRAS-mutant lung cancer patients, who have a poor prognosis and no targeted therapy available yet. Although several ATP-competitive inhibitors of CDK4 have been developed for anticancer therapeutics, they suffer from limited specificity and efficacy. Methods: As an alternative to ATP-competitive inhibitors we have designed a stapled peptide to target the main interface between CDK4 and cyclin D, and have characterized its physico-chemical properties and affinity to bind cyclin D1. Results: We have validated a positive correlation between CDK4/cyclin D level and KRAS mutation in lung cancer patients. The stapled peptide enters cells rapidly and efficiently, and inhibits CDK4 kinase activity and proliferation in lung cancer cells. Its intrapulmonary administration in mice enables its retention in orthotopic lung tumours and complete inhibition of their growth when co-administered with Abemaciclib. Conclusion: The stapled peptide targeting the main interface between CDK4 and cyclin D provides promising therapeutic perspectives for patients with lung cancer.

Verteporfin-Loaded Lipid Nanoparticles Improve Ovarian Cancer Photodynamic Therapy In Vitro and In Vivo.

Advanced ovarian cancer is the most lethal gynecological cancer, with a high rate of chemoresistance and relapse. Photodynamic therapy offers new prospects for ovarian cancer treatment, but current photosensitizers lack tumor specificity, resulting in low efficacy and significant side-effects. In the present work, the clinically approved photosensitizer verteporfin was encapsulated within nanostructured lipid carriers (NLC) for targeted photodynamic therapy of ovarian cancer. Cellular uptake and phototoxicity of free verteporfin and NLC-verteporfin were studied in vitro in human ovarian cancer cell lines cultured in 2D and 3D-spheroids, and biodistribution and photodynamic therapy were evaluated in vivo in mice. Both molecules were internalized in ovarian cancer cells and strongly inhibited tumor cells viability when exposed to laser light only. In vivo biodistribution and pharmacokinetic studies evidenced a long circulation time of NLC associated with efficient tumor uptake. Administration of 2 mg.kg-1 free verteporfin induced severe phototoxic adverse effects leading to the death of 5 out of 8 mice. In contrast, laser light exposure of tumors after intravenous administration of NLC-verteporfin (8 mg.kg-1) significantly inhibited tumor growth without visible toxicity. NLC-verteporfin thus led to efficient verteporfin vectorization to the tumor site and protection from side-effects, providing promising therapeutic prospects for photodynamic therapy of cancer.

A large scale proteome analysis of the gefitinib primary resistance overcome by KDAC inhibition in KRAS mutated adenocarcinoma cells overexpressing amphiregulin.

KDAC inhibitors (KDACi) overcome gefitinib primary resistance in non-small cell lung cancer (NSCLC) including mutant-KRAS lung adenocarcinoma. To identify which proteins are involved in the restoration of this sensitivity and to provide new therapeutic targets for mutant-KRAS lung adenocarcinoma, we performed an iTRAQ quantitative proteomic analysis after subcellular fractionation of H358-NSCLC treated with gefitinib and KDACi (TSA/NAM) versus gefitinib alone. The 86 proteins found to have been significantly dysregulated between the two conditions, were mainly involved in cellular metabolism and cell transcription processes. As expected, the pathway related to histone modifications was affected by the KDACi. Pathways known for controlling tumor development and (chemo)-resistance (miRNA biogenesis/glutathione metabolism) were affected by the KDACi/gefitinib treatment. Moreover, 57 dysregulated proteins were upstream of apoptosis (such as eEF1A2 and STAT1) and hence provide potential therapeutic targets. The inhibition by siRNA of eEF1A2 expression resulted in a slight decrease in H358-NSCLC viability. In addition, eEF1A2 and STAT1 siRNA transfections suggested that both STAT1 and eEF1A2 prevent AKT phosphorylation known for enhancing gefitinib resistance in NSCLC. Therefore, altogether our data provide new insights into proteome regulations in the context of overcoming the NSCLC resistance to gefitinib through KDACi in H358 KRAS mutated and amphiregulin-overexpressing NSCLC cells.

The pyrrolopyrimidine colchicine-binding site agent PP-13 reduces the metastatic dissemination of invasive cancer cells in vitro and in vivo.

Standard chemotherapies that interfere with microtubule dynamics are a chemotherapeutic option used for the patients with advanced malignancies that invariably relapse after targeted therapies. However, major efforts are needed to reduce their toxicity, optimize their efficacy, and reduce cancer chemoresistance to these agents. We previously identified a pyrrolo[2,3d]pyrimidine-based microtubule-depolymerizing agent (PP-13) that binds to the colchicine site of ß-tubulin and exhibits anticancer properties in solid human cancer cells, including chemoresistant subtypes. Here, we investigated the therapeutic potential of PP-13 in vitro and in vivo. PP-13 induced a mitotic blockade and apoptosis in several cancer cells cultured in two-dimensions or three-dimensions spheroids, in conjunction with reduced cell proliferation. Capillary-like tube formation assays using HUVECs showed that PP-13 displayed antiangiogenic properties. It also inhibited cancer cell motility and invasion, in in vitro wound-healing and transwell migration assays. Low concentration PP-13 (130 nmol.L-1) treatment significantly reduced the metastatic invasiveness of human cancer cells engrafts on chicken chorioallantoic membrane. In nude mice, 0.5 or 1 mg.kg-1 PP-13 intraperitoneally administered three-times a week reduced the sizes of paclitaxel-refractory orthotopic breast tumors, delayed the progression of metastasis, and decreased the global metastatic load compared to 0.5 mg.kg-1 paclitaxel or vehicle alone. PP-13 did not show any apparent early adverse effect in vivo. These data suggest that PP-13 is a promising alternative to standard chemotherapy in antimitotic drug-refractory tumors, especially through its impact on metastasis.

Design of RGD-ATWLPPR peptide conjugates for the dual targeting of αVß3 integrin and neuropilin-1.

Targeting the tumour microenvironment is a promising strategy to detect and/or treat cancer. The design of selective compounds that co-target several receptors frequently overexpressed in solid tumours may allow a reliable and selective detection of tumours. Here we report the modular synthesis of compounds encompassing ligands of αVß3 integrin and neuropilin-1 that are overexpressed in the tumour microenvironment. These compounds were then evaluated through cellular experiments and imaging of tumours in mice. We observed that the peptide that displays both ligands is more specifically accumulating in the tumours than in controls. Simultaneous interaction with αVß3 integrin and NRP1 induces NRP1 stabilization at the cell membrane surface which is not observed with the co-injection of the controls.

Anti-tumor efficacy of hyaluronan-based nanoparticles for the co-delivery of drugs in lung cancer.

Combinations of therapeutic agents could synergistically enhance the response of lung cancer cells. Co-delivery systems capable of transporting chemotherapeutics with different physicochemical properties and with the simultaneous release of drugs remain elusive. Here, we assess the ability of nanoparticles of 30-nm diameter obtained from the self-assembly of hyaluronan-based copolymer targeting CD44 receptors to encapsulate both gefitinib and vorinostat for effective combinational lung cancer treatment. Drug loading was performed by nanoprecipitation. Drug release experiments showed a slow release of both drugs after 5 days. Using two- and three-dimensional lung adenocarcinoma cell cultures, we observed that the nanoparticles were mostly found at the periphery of the CD44-expressing spheroids. These drug-loaded nanoparticles were as cytotoxic as free drugs in the two- and three-dimensional systems and toxicity was due to apoptosis induction. In mouse models, intravenous injection of hyaluronan-based nanoparticles showed a selective delivery to subcutaneous CD44-overexpressing tumors, despite a significant liver capture. In addition, the systemic toxicity of the free drugs was reduced by their co-delivery using the nanoparticles. Finally, intrapulmonary administration of drug-loaded nanoparticles, to avoid a possible hepatic toxicity due to their accumulation in the liver, showed a stronger inhibition of orthotopic lung tumor growth compared to free drugs. In conclusion, hyaluronan-based nanoparticles provide active targeting partially mediated by CD44, less-toxic drug release and improved antitumor efficiency.

Nuclear translocation of IGF1R by intracellular amphiregulin contributes to the resistance of lung tumour cells to EGFR-TKI.

Many Receptor Tyrosine Kinases translocate from the cell surface to the nucleus in normal and pathological conditions, including cancer. Here we report the nuclear expression of insulin-like growth factor-1 receptor (IGF1R) in primary human lung tumours. Using lung cancer cell lines and lung tumour xenografts, we demonstrate that the epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) gefitinib induces the nuclear accumulation of IGF1R in mucinous lung adenocarcinoma by a mechanism involving the intracellular re-localization of the growth factor amphiregulin. Amphiregulin allows the binding of IGF1R to importin-ß1 and promotes its nuclear transport. The nuclear accumulation of IGF1R by amphiregulin induces cell cycle arrest through p21WAF1/CIP1 upregulation, and prevents the induction of apoptosis in response to gefitinib. These results identify amphiregulin as the first nuclear localization signal-containing protein that interacts with IGF1R and allows its nuclear translocation. Furthermore they indicate that nuclear expression of IGF1R contributes to EGFR-TKI resistance in lung cancer.

Identification of pyrrolopyrimidine derivative PP-13 as a novel microtubule-destabilizing agent with promising anticancer properties.

Despite the emergence of targeted therapies and immunotherapy, chemotherapy remains the gold-standard for the treatment of most patients with solid malignancies. Spindle poisons that interfere with microtubule dynamics are commonly used in chemotherapy drug combinations. However, their troublesome side effects and the emergence of chemoresistance highlight the need for identifying alternative agents. We performed a high throughput cell-based screening and selected a pyrrolopyrimidine molecule (named PP-13). In the present study, we evaluated its anticancer properties in vitro and in vivo. We showed that PP-13 exerted cytotoxic effects on various cancer cells, including those resistant to current targeted therapies and chemotherapies. PP-13 induced a transient mitotic blockade by interfering with both mitotic spindle organization and microtubule dynamics and finally led to mitotic slippage, aneuploidy and direct apoptotic death. PP-13 was identified as a microtubule-targeting agent that binds directly to the colchicine site in ß-tubulin. Interestingly, PP-13 overcame the multidrug-resistant cancer cell phenotype and significantly reduced tumour growth and metastatic invasiveness without any noticeable toxicity for the chicken embryo in vivo. Overall, PP-13 appears to be a novel synthetic microtubule inhibitor with interesting anticancer properties and could be further investigated as a potent alternative for the management of malignancies including chemoresistant ones.

Synergistic activity of vorinostat combined with gefitinib but not with sorafenib in mutant KRAS human non-small cell lung cancers and hepatocarcinoma.

Development of drug resistance limits the efficacy of targeted therapies. Alternative approaches using different combinations of therapeutic agents to inhibit several pathways could be a more effective strategy for treating cancer. The effects of the approved epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (gefitinib) or a multi-targeted kinase inhibitor (sorafenib) in combination with a histone deacetylase inhibitor (vorinostat) on cell proliferation, cell cycle distribution, apoptosis, and signaling pathway activation in human lung adenocarcinoma and hepatocarcinoma cells with wild-type EGFR and mutant KRAS were investigated. The effects of the synergistic drug combinations were also studied in human lung adenocarcinoma and hepatocarcinoma cells in vivo. The combination of gefitinib and vorinostat synergistically reduced cell growth and strongly induced apoptosis through inhibition of the insulin-like growth factor-1 receptor/protein kinase B (IGF-1R/AKT)-dependent signaling pathway. Moreover, the gefitinib and vorinostat combination strongly inhibited tumor growth in mice with lung adenocarcinoma or hepatocarcinoma tumor xenografts. In contrast, the combination of sorafenib and vorinostat did not inhibit cell proliferation compared to a single treatment and induced G2/M cell cycle arrest without apoptosis. The sorafenib and vorinostat combination sustained the IGF-1R-, AKT-, and mitogen-activated protein kinase-dependent signaling pathways. These results showed that there was synergistic cytotoxicity when vorinostat was combined with gefitinib for both lung adenocarcinoma and hepatocarcinoma with mutant KRAS in vitro and in vivo but that the combination of vorinostat with sorafenib did not show any benefit. These findings highlight the important role of the IGF-1R/AKT pathway in the resistance to targeted therapies and support the use of histone deacetylase inhibitors in combination with EGFR-tyrosine kinase inhibitors, especially for treating patients with mutant KRAS resistant to other treatments.

Targeting CD44 receptor-positive lung tumors using polysaccharide-based nanocarriers: Influence of nanoparticle size and administration route.

New approaches that are more efficient and able to specifically reach lung tumors are needed. We developed new hyaluronan-based nanoparticles targeting CD44 receptors of two different sizes and compared their lung cancer cells targeting efficacy in vitro and in vivo. The nanoparticles' cellular uptake was dose-dependent, and specific to hyaluronan receptors, particularly CD44. The binding and internalization differed according to nanoparticle size. In vivo biodistribution studies in two orthotopic lung tumor models showed that intrapulmonary nebulized nanoparticles accumulated in lungs, but not in the tumor nodules. In contrast, despite a significant liver capture, intravenous injection led to a better accumulation of the nanoparticles in the lung tumors compared with the surrounding healthy lung tissues. We demonstrated that the hyaluronan-based nanoparticles size plays significant role in cellular uptake and biodistribution. Small nanoparticles showed active targeting of CD44-overexpressing tumors, suggesting that they could be used as drug-delivery system. FROM THE CLINICAL EDITOR: Combating cancers remains an important goal in clinical medicine. In this study, the authors investigated the ability of two hyaluronan-based nanoparticles targeting CD44 receptors to home in on lung cancer cells in an in-vivo orthotropic model. The preferential uptake of smaller sized nanoparticles via intravenous route has further enhanced the existing knowledge of future drug designs.