Human Colon Cancer Xenograft Model Research Articles

Abstract 6727: QL335, a novel T cell engager with enhanced safety profile targeting MSS colorectal cancer

Abstract Colorectal cancer (CRC) is the fourth leading cause of death in the world with a global mortality rate of over 700,000 annually. While recent advancement in diagnosis and prevention has reduced the overall number of deaths, the lack of effective and durable treatment has not significantly improved survival rate. Emerging modalities in immunotherapy such as T cell engagers have paved new ways for disease management. However, a common challenge to advancing T cell engagers in the clinic is poor target specificity and high toxicity associated with non-specific T cell activation and cytokine release. To overcome these shortcomings, we have developed QL335, a bispecific antibody bridging LY6G6D antigen on tumor cells and CD3 on T cells. LY6G6D or Lymphocyte Antigen 6 Family Member G6D, is a GPI-anchored membrane protein that, according to TCGA RNAseq data, is highly expressed in microsatellite stable (MSS) colorectal cancer but not in normal tissues. We analyzed LY6G6D expression by IHC in over 200 CRC patient tumors and 40+ normal tissue samples from different organs, confirming its highly restricted CRC expression pattern. We constructed our bispecific antibody in a 2+1 format, comprising two high affinity LY6G6D binding domains and one reduced affinity CD3 binding domain. Such format allows for higher tumor accumulation while mitigating non-specific T cell activation in the periphery. In vitro evaluation showed that QL335 induced potent yet highly specific T cell activation and killing of only target cells expressing LY6G6D. QL335 demonstrated robust anti-tumor efficacy in vivo against human colon cancer xenograft models with human PBMC reconstitution. Importantly, QL335 was well tolerated in cynomolgus monkeys dosed up to 50 mg/kg, supporting the enhanced safety profile by design of this therapeutic candidate. QL335 is currently being evaluated in a phase 1 clinical trial. Citation Format: Shenda Gu, Guangjie Guo, Helena Yee, Hieu V. Tran, Shihao Chen, Chuanzeng Cao, Ke Liu, Chunyan Jin, Weihua Lun, Ruixue Ma, Lele Ren. QL335, a novel T cell engager with enhanced safety profile targeting MSS colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6727.

Prolyl hydroxylase 2 inhibits glycolytic activity in colorectal cancer via the NF‑κB signaling pathway.

A variety of malignancies preferentially meet energy demands through the glycolytic pathway. Hypoxia‑induced cancer cell adaptations are essential for tumor development. However, in cancerous glycolysis, the functional importance and underlying molecular mechanism of prolyl hydroxylase domain protein 2 (PHD2) have not been fully elucidated. Gain‑ and loss‑of‑function assays were conducted to evaluate PHD2 functions in colon cancer cells. Glucose uptake, lactate production and intracellular adenosine‑5'‑triphosphate/adenosine diphosphate ratio were measured to determine glycolytic activities. Protein and gene expression levels were measured by western blot analysis and reverse transcription‑quantitative PCR, respectively. The human colon cancer xenograft model was used to confirm the role of PHD2 in tumor progression invivo. Functionally, the data demonstrated that PHD2 knockdown leads to increased glycolysis, while PHD2 overexpression resulted in suppressed glycolysis in colorectal cancer cells. In addition, the glycolytic activity was enhanced without PHD2 and normalized after PHD2 reconstitution. PHD2 was shown to inhibit colorectal tumor growth, suppress cancer cell proliferation and improve tumor‑bearing mice survival invivo. Mechanically, it was found that PHD2 inhibits the expression of critical glycolytic enzymes (glucose transporter 1, hexokinase 2 and phosphoinositide‑dependent protein kinase 1). In addition, PHD2 inhibited Ikkβ‑mediated NF‑κB activation in a hypoxia‑inducible factor‑1α‑independent manner. In conclusion, the data demonstrated that PHD2/Ikkβ/NF‑κB signaling has critical roles in regulating glycolysis and suggests that PHD2 potentially suppresses colorectal cancer.

Pre-clinical safety and therapeutic efficacy of a plant-based alkaloid in a human colon cancer xenograft model

A high-throughput drug screen revealed that veratridine (VTD), a natural plant alkaloid, induces expression of the anti-cancer protein UBXN2A in colon cancer cells. UBXN2A suppresses mortalin, a heat shock protein, with dominant roles in cancer development including epithelial–mesenchymal transition (EMT), cancer cell stemness, drug resistance, and apoptosis. VTD-dependent expression of UBXN2A leads to the deactivation of mortalin in colon cancer cells, making VTD a potential targeted therapy in malignant tumors with high levels of mortalin. VTD was used clinically for the treatment of hypertension in decades past. However, the discovery of newer antihypertensive drugs and concerns over potential neuro- and cardiotoxicity ended the use of VTD for this purpose. The current study aims to determine the safety and efficacy of VTD at doses sufficient to induce UBXN2A expression in a mouse model. A set of flow-cytometry experiments confirmed that VTD induces both early and late apoptosis in a dose-dependent manner. In vivo intraperitoneal (IP) administration of VTD at 0.1 mg/kg every other day (QOD) for 4 weeks effectively induced expression of UBXN2A in the small and large intestines of mice. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) assays on tissues collected from VTD-treated animals demonstrated VTD concentrations in the low pg/mg range. To address concerns regarding neuro- and cardiotoxicity, a comprehensive set of behavioral and cardiovascular assessments performed on C57BL/6NHsd mice revealed that VTD generates no detectable neurotoxicity or cardiotoxicity in animals receiving 0.1 mg/kg VTD QOD for 30 days. Finally, mouse xenograft experiments in athymic nude mice showed that VTD can suppress tumor growth. The main causes for the failure of experimental oncologic drug candidates are lack of sufficient safety and efficacy. The results achieved in this study support the potential utility of VTD as a safe and efficacious anti-cancer molecule.

Enhanced anticancer effect of quercetin microparticles formulation obtained by spray drying

AbstractThis study unravels a formulation made of food‐based microparticles (MPs) able to control the release of quercetin, a natural anticancer compound, which activity is only limited by its poor aqueous solubility and consequent low bioavailability. To solve this issue, a spray‐dried micro delivery system was developed using a bench mini spray dryer B290 Buchi. The resulting MPs were only manufactured with food‐derived ingredients such as whey proteins and milk, avoiding the use of any other synthetic material. These microparticles were characterised with a testing campaign encompassing either the physical–chemical characterisation with SEM, DSC and DLS, or the technological and biological features with in vitro, ex vivo and in vivo studies, the latter being characterised by a human colon cancer xenograft model. These studies showed as the quercetin solubility and release rate improved when tested in condition mimicking oral administration, resulting in a general improvement of its bioavailability and the consequent anticancer activity. This study shows as the whey proteins may serves as natural adjuvant able to provide valuable technological features when used to manufactures micro carriers by spray drying.

A multicenter phase Ib/II study of DNA-PK inhibitor peposertib (M3814) in combination with capecitabine and radiotherapy in patients with locally advanced rectal cancer.

TPS144 Background: Perioperative radiotherapy and chemotherapy, followed by total mesorectal excision, is the standard of care for patients with locally advanced rectal cancer (LARC). However, 1/3 of these patients still develop distant metastases, indicating the need for more effective therapies. In addition, strategies that increase pathological complete response rates are needed to enable non-surgical management of LARC. DNA-dependent protein kinase (DNA-PK) regulates a key DNA damage repair pathway for double-strand break repair. Peposertib (M3814), a potent, selective, orally administered DNA-PK inhibitor, has been shown to potentiate the effect of ionizing radiation in a human colon cancer xenograft model and several colon cancer cell lines. Peposertib is being investigated in several different trials across multiple indications. This Phase Ib/II study (NCT03770689) aims to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of the neoadjuvant treatment combination of peposertib, capecitabine, and radiotherapy (RT) in patients with LARC. Methods: Patients aged ≥18 years with histologically confirmed and resectable Stage II/III rectal adenocarcinoma are eligible. Induction chemotherapy is permitted, but residual disease must first be documented by MRI, digital rectal examination and endoscopy. Patients who received other anticancer therapies or those with prior pelvic RT are excluded. At open-label Phase Ib (open), 18–30 patients (n = 3 per cohort) will receive peposertib + capecitabine (orally, 825 mg/m2 twice daily [BID]) + RT (45–50.4 Gy), 5 days/week. Peposertib 50 mg once daily (QD) was the starting dose. Additional dose levels will range between 100─800 mg QD. Dose escalation is determined by the safety monitoring committee and guided by a Bayesian 2-parameter logistic regression model. At Phase II (planned), 150 patients will be randomized (1:1) to receive oral capecitabine (825 mg/m2 BID) + RT (45–50 Gy), with either oral peposertib (recommended phase II dose [RP2D] or placebo, QD for 5 days/week. Primary objectives are to define a maximum tolerated dose and RP2D (Phase Ib), and to evaluate the efficacy of peposertib + capecitabine + RT in terms of pathological/clinical complete response (Phase II). Secondary objectives include assessment of antitumor activity (Phase Ib), quality of life outcomes (Phase II), and PK of peposertib, and the safety and tolerability of the combination therapy (both phases). To date, one patient has received peposertib 50 mg QD, six patients peposertib 100 mg QD, three patients peposertib 150 mg QD, and three patients peposertib 250 mg QD. Clinical trial information: NCT03770689.

ABL001, a Bispecific Antibody Targeting VEGF and DLL4, with Chemotherapy, Synergistically Inhibits Tumor Progression in Xenograft Models.

Delta-like-ligand 4 (DLL4) is a promising target to augment the effects of VEGF inhibitors. A simultaneous blockade of VEGF/VEGFR and DLL4/Notch signaling pathways leads to more potent anti-cancer effects by synergistic anti-angiogenic mechanisms in xenograft models. A bispecific antibody targeting VEGF and DLL4 (ABL001/NOV1501/TR009) demonstrates more potent in vitro and in vivo biological activity compared to VEGF or DLL4 targeting monoclonal antibodies alone and is currently being evaluated in a phase 1 clinical study of heavy chemotherapy or targeted therapy pre-treated cancer patients (ClinicalTrials.gov Identifier: NCT03292783). However, the effects of a combination of ABL001 and chemotherapy on tumor vessels and tumors are not known. Hence, the effects of ABL001, with or without paclitaxel and irinotecan were evaluated in human gastric or colon cancer xenograft models. The combination treatment synergistically inhibited tumor progression compared to each monotherapy. More tumor vessel regression and apoptotic tumor cell induction were observed in tumors treated with the combination therapy, which might be due to tumor vessel normalization. Overall, these findings suggest that the combination therapy of ABL001 with paclitaxel or irinotecan would be a better clinical strategy for the treatment of cancer patients.

Pyrido[2, 3-d]pyrimidin-7(8H)-ones as new selective orally bioavailable Threonine Tyrosine Kinase (TTK) inhibitors.

A series of pyrido [2, 3-d]pyrimidin-7(8H)-ones were designed and synthesized as new selective orally bioavailable Threonine Tyrosine Kinase (TTK) inhibitors. One of the representative compounds, 5o, exhibited strong binding affinity with a Kd value of 0.15nM, but was significantly less potent against a panel of 402 wild-type kinases at 100nM. The compound also potently inhibited the kinase activity of TTK with an IC50 value of 23nM, induced chromosome missegregation and aneuploidy, and suppressed proliferation of a panel of human cancer cell lines with low μM IC50 values. Compound 5o demonstrated good oral pharmacokinetic properties with a bioavailability value of 45.3% when administered at a dose of 25mg/kg in rats. Moreover, a combination therapy of 5o with paclitaxel displayed promising invivo efficacy against the HCT-116 human colon cancer xenograft model in nude mice with a Tumor Growth Inhibition (TGI) value of 78%. Inhibitor 5o may provide a new research tool for further validating therapeutic potential of TTK inhibition.

Abstract 1715: Anti-cancer activity of a SN-38 nanoparticle, DEP® irinotecan, in human colon cancer xenograft models

Abstract Irinotecan (Camptosar®) is a water-soluble prodrug of the potent topoisomerase I inhibitor SN-38 used clinically to treat multiple cancers. Irinotecan must be metabolized to its active metabolite SN-38 by carboxylesterases in hepatic and tumor cells. This metabolism in humans is inefficient with significant interpatient variability and leads to serious toxicities, notably diarrhea and myelosuppression. The narrow therapeutic window of irinotecan makes it an ideal candidate for improvement using dendrimer nanomedicine delivery. Starpharma's novel dendrimer nanoparticle DEP® platform has broad applicability in drug delivery, enhancing the therapeutic utility of drugs through improved solubility, efficacy and pharmacokinetics, reductions in certain toxicities (e.g. bone marrow toxicity) and providing novel intellectual property. The DEP platform has shown reproducible advantages across a wide range of drug classes including small molecule, peptides and proteins. Starpharma's DEP irinotecan is a PEGylated polylysine dendrimer with SN-38 conjugated to the surface via a hydrolytically labile linker. The incorporation of the active metabolite, SN-38 avoids the need for hepatic conversion and thereby minimizes variability in SN-38 levels. In preclinical studies, DEP irinotecan has shown to be well tolerated in animals. Efficacy assessments have been conducted, using a range of xenograft cancer models [SW620 (colon), HT-29 (colon), MDA-MB-231 (Breast) and CAPAN-1 (pancreatic)]. These studies demonstrated significant efficacy and survival benefits of DEP irinotecan compared to standard irinotecan. DEP irinotecan also showed significant benefit when dosed in combination with current standard of care therapies such as the anti-EGFR antibody, cetuximab, and the PARP inhibitor, olaparib. DEP irinotecan in combination with olaparib, significantly improved anti-tumor efficacy leading to tumor regression and extended median survival by 28 days compared to DEP irinotecan alone (P<0.0001, Mantel Cox Log rank test) whereas olaparib alone had minimal activity. This result highlights the synergistic combination benefits that can be achieved using DEP technology. DEP irinotecan is Starpharma's third internal DEP candidate to enter the clinic. The fourth DEP candidate, AZD0466 is a promising Bcl-2/Bcl-xL inhibitor and is partnered with AstraZeneca. AZD0466, is currently transitioning into clinical trials in the US. In summary, DEP irinotecan is well tolerated and allows for the delivery of SN-38 by successfully utilizing dendrimer drug delivery technology. The dendrimer nanoparticle shows significant efficacy and survival benefits compared to current standard of care therapies when used either as a monotherapy or in combination. DEP irinotecan is currently in a phase 1 / 2 adaptive trial at leading UK hospitals; The Christie, The Royal Marsden and The Newcastle Upon Tyne. Citation Format: Brian D. Kelly, Victoria McLeod, Rachael Walker, Jeannette Schreuders, Susan Jackson, Michael Giannis, Christine Dietinger, Shirley Xia, Anne Cargill, Aynaz Seta, Richard Hufton, Graham Heery, Carleen Cullinane, David J. Owen. Anti-cancer activity of a SN-38 nanoparticle, DEP® irinotecan, in human colon cancer xenograft models [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1715.

A multicenter phase Ib/II study of DNA-PK inhibitor peposertib (M3814) in combination with capecitabine and radiotherapy in patients with locally advanced rectal cancer.

TPS4117 Background: Preoperative chemo-radiotherapy with or without sequential chemotherapy, followed by surgical intervention, is standard of care for patients with locally advanced rectal cancer (LARC). However, 1/3 of these patients still develop distant metastases, indicating the need for more effective therapies. DNA-dependent protein kinase (DNA-PK) regulates a key DNA damage repair pathway for double-strand break repair. Peposertib (M3814), a potent, selective, orally administered DNA-PK inhibitor, has been shown to potentiate the effect of ionizing radiation in a human colon cancer xenograft model and several colon cancer cell lines. Peposertib is being investigated in several different trials across multiple indications. This Phase Ib/II study (NCT03770689) aims to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of the neoadjuvant treatment combination of peposertib, capecitabine, and radiotherapy (RT) in patients with LARC. Methods: Patients aged ≥18 years with histologically confirmed and resectable Stage II/III rectal adenocarcinoma are eligible. Induction chemotherapy is permitted, but residual disease must first be documented by MRI, digital rectal examination and endoscopy. Patients who received other anticancer therapies or those with prior pelvic RT are excluded. During open-label Phase Ib (open), 18–30 patients (n = 3 per cohort) are due to receive peposertib + capecitabine (orally, 825 mg/m2 twice daily [BID]) + RT (45–50 Gy), 5 days/week. Peposertib 50 mg once daily (QD) is the starting dose. Additional dose levels will be between 100─800 mg QD. Dose escalation is determined by the safety monitoring committee and guided by a Bayesian 2-parameter logistic regression model. At Phase II (planned), 150 patients will be randomized (1:1) to receive oral capecitabine (825 mg/m2 BID) + RT (45–50 Gy), with either oral peposertib (recommended phase II dose [RP2D]) or placebo, QD for 5 days/week. Primary objectives are to define a maximum tolerated dose and RP2D (Phase Ib), and to evaluate the efficacy of peposertib + capecitabine + RT in terms of pathological/clinical complete response (Phase II). Secondary objectives include assessment of antitumor activity (Phase Ib), quality of life outcomes (Phase II), and PK of peposertib, and the safety and tolerability of the combination therapy (both phases). One patient has received peposertib 50 mg QD and six patients have received peposertib 100 mg QD. Patients are currently receiving peposertib 150 mg QD. Clinical trial information: NCT03770689 .

Discovery of a Potent Anticancer Agent PVHD303 with in Vivo Activity.

As a part of our continuous structure-activity relationship (SAR) studies on 1-(quinazolin-4-yl)-1-(4-methoxyphenyl)ethan-1-ols, the synthesis of derivatives and their cytotoxicity against the human lung cancer cell line A549 were explored. This led to the discovery of 1-(2-(furan-3-yl)quinazolin-4-yl)-1-(4-methoxyphenyl)ethan-1-ol (PVHD303) with potent antiproliferative activity. PVHD303 disturbed microtubule formation at the centrosomes and inhibited the growth of tumors dose-dependently in the HCT116 human colon cancer xenograft model in vivo.

Oncolytic properties of non-vaccinia poxviruses.

Vaccinia virus, a member of the Poxviridae family, has been extensively used as an oncolytic agent and has entered late stage clinical development. In this study, we evaluated the potential oncolytic properties of other members of the Poxviridae family. Numerous tumor cell lines were infected with ten non-vaccinia poxviruses to identify which virus displayed the most potential as an oncolytic agent. Cell viability indicated that tumor cell lines were differentially susceptible to each virus. Raccoonpox virus was the most potent of the tested poxviruses and was highly effective in controlling cell growth in all tumor cell lines. To investigate further the oncolytic capacity of the Raccoonpox virus, we have generated a thymidine kinase (TK)-deleted recombinant Raccoonpox virus expressing the suicide gene FCU1. This TK-deleted Raccoonpox virus was notably attenuated in normal primary cells but replicated efficiently in numerous tumor cell lines. In human colon cancer xenograft model, a single intratumoral inoculation of the recombinant Raccoonpox virus, in combination with 5-fluorocytosine administration, produced relevant tumor growth control. The results demonstrated significant antitumoral activity of this new modified Raccoonpox virus armed with FCU1 and this virus could be considered to be included into the growing armamentarium of oncolytic virotherapy for cancer.

Abstract 5920: Antitumor efficacy of a dual stromal and tumor targeted oncolytic measles virus in breast and colon cancer models

Abstract Efficient systemic delivery of oncolytic viruses remains an unresolved issue and an obstacle to the success of oncolytic virotherapy. One of the main barriers that lead to decreased oncolytic viral delivery to tumor cells is the tumor stromal component. A potential strategy to circumvent this problem is to use a retargeted oncolytic virus that is able to target, and replicate in tumor stromal cells. The aim of this study is to evaluate the consequences of tumor stromal/vascular targeting by oncolytic measles virus via urokinase receptor (uPAR) as they relate to improved viral delivery and antitumor efficacy. We rescued and characterized a novel dual targeting MV-un-muPA, which binds human cancer cells via CD46 and murine tissues via murine uPAR. This novel virus variant was generated as a tool to investigate the ability of a virus to target tumor stromal cells, especially tumor microvasculature (via murine uPAR) and deliver the infection to tumor cells (via CD46) in vivo. In vitro, MV-un-muPA infected and induced cytotoxicity to human or murine cancer cells in a species specific manner. Efficient MV-un-muPA replication was demonstrated in multiple human and murine cancer cells as well as murine fibroblasts in vitro. MV-un-muPA mediated viral transfer was demonstrated between murine endothelial or murine fibroblast to (RFP expressing) human cancer cells. To further validate the consequences of tumor stromal/vascular targeting by oncolytic measles virus via uPAR as they relate to improved viral delivery, the effects of MV-un-muPA vs a non-targeted MV virus (MV-GFP) were assessed in human breast (MDA-MD231) and colon (HT-29) cancer xenograft models. In these models, tumor cells express human CD46 and the host stroma expresses murine uPAR. Tumor bearing mice were treated with MV-GFP (targeting tumor cells via CD46), dual targeting virus MV-un-muPA (target tumor stroma via murine uPAR, and tumor cells via CD46) by intravenous administration (3 doses). Systemic administration of MV-un-muPA resulted in a significant delay in tumor progression as well as improved survival compared to mice treated with vehicle control or MV-GFP. Tumor based studies showed increased levels of viral RNA, tumor apoptosis, resulted in a significantly reduced stroma and the reduction of cancer associated fibroblasts and endothelial cells, in tumors treated with the dual targeted virus, compared to MV-GFP. In conclusion, our results demonstrate for the first time that dual targeting of tumor stroma and tumor cells by MV-un-m-uPA enhance in vivo viral delivery and oncolytic virus antitumor efficacy in two in vivo models of cancer. This serves as clear proof that vascular/stromal targeting is an effective strategy to enhance viral delivery and antitumor effects and support future studies to further uncover the potential of stromal targeted oncolytic viruses. Citation Format: Yuqi Jing, Valery Chavez, Natasha Karishma Khatwani, Jaime Merchan. Antitumor efficacy of a dual stromal and tumor targeted oncolytic measles virus in breast and colon cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5920.

Construction and Evaluation of a Targeted Hyaluronic Acid Nanoparticle/Photosensitizer Complex for Cancer Photodynamic Therapy.

Photodynamic therapy (PDT) is a novel treatment modality that is under intensive preclinical investigations for a variety of diseases, including cancer. Despite extensive studies in this area, selective and effective photodynamic agents that can specifically accumulate in tumors to reach a therapeutic concentration are limited. Although recent attempts have produced photosensitizers (PSs) complexed with various nanomaterials, the tedious preparation steps and poor tumor efficiency of therapy hamper their utilization. Here, we developed a CD44-targeted nanophotodynamic agent by physically encapsulating a photosensitizer, Ce6, into a hyaluronic acid nanoparticle (HANP), which was hereby denoted HANP/Ce6. Its physical features and capability for photodynamic therapy were characterized in vitro and in vivo. Systemic delivery of HANP/Ce6 resulted in its accumulation in a human colon cancer xenograft model. The tumor/muscle ratio reached 3.47 ± 0.46 at 4 h post injection, as confirmed by fluorescence imaging. Tumor growth after HANP/Ce6 treatment with laser irradiation (0.15 W/cm2, 630 nm) was significantly inhibited by 9.61 ± 1.09-fold compared to that in tumor control groups, which showed no change in tumor growth. No apparent systemic and local toxic effects on the mice were observed. HANP/Ce6-mediated tumor growth inhibition was accessed and observed for the first time by 18F-fluoro-2-deoxy-d-glucose positron emission tomography as early as 1 day after treatment and persisted for 14 days within our treatment time window. In sum, our results highlight the imaging properties and therapeutic effects of the novel HANP/Ce6 theranostic nanoparticle for CD44-targeted PDT cancer therapy that may be potentially utilized in the clinic. This HANP system may also be applied for the delivery of other hydrophobic PSs, particularly those that could not be chemically modified.

Functional-segregated coumarin-containing telodendrimer nanocarriers for efficient delivery of SN-38 for colon cancer treatment

Four coumarin-containing telodendrimers (denoted as P-I, P-II, P-III and P-IV) were designed and synthesized to self-assemble into the corresponding nanoparticles. Of those, two nanoparticles (P-II and P-IV micelles) were screened and selected for targeted drug delivery of 7-ethyl-10-hydroxy camptothecin (SN-38), a prominent and efficacious anticancer agent, for the treatment of colon cancers. The nanoparticle encapsulation significantly increased the solubility of SN-38 in aqueous solution. Dynamic light scattering (DLS) showed the size of these SN-38 nanoparticles to be around 50nm, and rod-shaped micelles were observed using transmission electron microscopy (TEM). These two novel nanoformulations of SN-38/P-II and SN-38/P-IV were found to exhibit similar in vitro cytotoxic activity against colon cancer cells as the free drug (SN-38 in DMSO) and were 500-fold more potent than irinotecan (a prodrug of SN-38). In addition, near infrared fluorescent (NIRF) optical imaging was utilized to monitor the tumor targeted delivery of SN-38/NPs via co-loading a NIRF dye. It was demonstrated that these NPs preferentially accumulated in tumors when compared to healthy tissue. A pharmacokinetics study showed that SN-38 micelle formulations had a longer circulating time in blood than irinotecan. Furthermore, SN-38 loaded nanoformulations exhibit superior anti-tumor efficacy when compared with irinotecan at equivalent SN-38 dose in HT-29 human colon cancer xenograft models.

Vaccinia Virus-Mediated Expression of Transcription Factor Klf4 Enhances Oncolytic Virotherapy of Colorectal Cancer

Colorectal cancer (CRC) detected at an early stage has a good prognosis, however, recurrence of the disease is prevalent and late stage CRC (stage IIIC and IV) has observed 5-year survival rates of 28% and 6%, respectively. Oncolytic virotherapy has been explored as a potential treatment modality in cancer therapy for its safety and tumor specificity. We recently reported that oncolytic vaccinia virus GLV-1h68 efficiently infected, replicated in, and lysed different colorectal cancer cell lines derived from patients at different stages of the disease in culture and mouse xenograft models. However, the cytotoxicity of GLV-1h68 was cell line- dependent and, in particular, xenograft tumors of the colorectal cancer cell line HT-29 did not respond favorably to oncolytic treatment with GLV-1h68. Here we report on the generation of recombinant vaccinia viruses expressing the colorectal tumor suppressor Klf4. We show that a single injection of vaccinia virus expressing Klf4 led to significant tumor growth inhibition of HT-29 human colon cancer xenografts in comparison to treatment with GLV-1h68. Furthermore, virus-mediated expression of a membrane-permeable Klf4-TAT fusion protein, further improved the anti-tumoral effects. This is the first report demonstrating that arming oncolytic viruses with the colorectal tumor suppressor Klf4 led to improved therapy in a human colon cancer xenograft model.

Therapeutic potential of transgenic mesenchymal stem cells engineered to mediate anti–high mobility group box 1 activity: targeting of colon cancer

BackgroundMesenchymal stem cells (MSCs) are being developed as a new clinically relevant stem cell type to be recruited into and to repair injured tissue. A number of studies have focused on the therapeutic potential of MSCs by virtue of their immunomodulatory properties. Systemically administered MSCs can also migrate to sites of malignancies. Because of this latter phenomenon, we transfected human MSCs to secrete anti–high mobility group box (HMGB) 1 proteins. They were then injected into mice bearing human colon cancer to evaluate their efficacy as an antineoplastic agent. Materials and methodsThe ABOX gene was used in this model, which encodes part of the HMGB1 protein and acts as an HMGB1 antagonist. It was cotransduced by electroporation with a FLAG-tag to visualize the secreted ABOX protein, levels of which in supernatants from cultured transfected MSCs were quantified by immunofluorescence imaging using an anti-FLAG antibody. Antiangiogenic effects were evaluated in vitro using a novel optical assay device for the quantitative measurement of cellular chemotaxis assessing the velocity and direction of endothelial cell movement stimulated by supernatant from tumor cells. We found that ABOX proteins released from transfected MSCs suppressed migration in this assay. Finally, MSCs were injected subcutaneously into Nonobese diabetic/severe combined immunodeficiency mice bearing human colon cancer from a cell line, which secreted large amounts of HMGB1. Ten days after MSC injection, mice were sacrificed and tumors evaluated by immunohistochemistry. ResultsFrom 12 ho through 7 d after gene transfection, ABOX proteins secreted from MSCs could be detected by immunofluorescence and enzyme-linked immunosorbent assay. Quantitative measurement of cellular chemotaxis demonstrated that ABOX proteins secreted from transfected MSCs decreased the velocity and interfered with the direction of movement of vascular endothelial cells. Moreover, in an in vivo human colon cancer xenograft model, injection of anti-HMGB1–transfected MSCs resulted in a decreased tumor volume due to the antiangiogenic properties of the secreted ABOX proteins. ConclusionsMSC modified to secrete HMGB1 antagonist proteins have therapeutic antineoplastic potential. These findings may contribute to future novel targeting strategies using autologous bone marrow–derived cells as gene delivery vectors.

Characterization of oleanolic acid derivative for colon cancer targeting with positron emission tomography

Oleanolic acid (OA) is a pentacyclic triterpenoid found in various plant species. Triterpenoid compounds have been shown to inhibit tumor proliferation and to induce apoptosis in cancer cells. We synthesized an OA derivative and evaluated its inhibitory effects on cell proliferation in human colon cancer. Radioisotope-labeled OA was prepared for noninvasive monitoring of tumor progression in vitro and in vivo. The OA derivative decreased cell survival in a concentration-dependent manner and increased apoptosis in HT-29 cells. Furthermore, it induced downregulation of cyclin D1, Cox-2, Bcl-2 and Bcl-xL mRNA expression and upregulation of the mRNA expression of the anti-apoptotic Bax protein in HT29 cells. NF-κB p65 and IκB expression also decreased, whereas expression of the apoptosis marker, the cleaved form of PARP-1, significantly increased in OA derivative-treated HT-29 cells. Radioisotope-labeled OA (68Ga-NOTA-OA) showed significantly high tumor uptake, as assessed by biodistribution and positron emission tomography imaging analyses, at 1 h post-injection in the human colon cancer xenograft model. Our results demonstrate that the OA derivative has promising properties as an anticancer drug and as an imaging tool for tumor targeting.

Total alkaloids of Tripterygium hypoglaucum (levl.) Hutch inhibits tumor growth both in vitro and in vivo

Ethnopharmacological relevanceTripterygium hypoglaucum (levl.) Hutch (Celastraceae) (THH) root is a traditional Chinese medicinal herb commonly used for treating autoimmune diseases and cancer. Alkaloid is one of the most bioactive components of THH extract. To evaluate the in vitro and in vivo antitumor properties of the total alkaloids of THH (THHta). Materials and methodsTHHta was extracted in pilot-scale. HCT116 cells were chose to establish human colon cancer xenograft model. The in vitro anti-tumor activity of THHta was tested by Cell malignant transformation test, Soft agar colony formation assay and MTT assay. The in vivo anti-tumor effect of THHta was confirmed by xenograft mouse model. THHta-induced apoptosis was examined by flow cytometry. The levels of apoptosis-related proteins were investigated by Western blot. ResultsTPA-induced cell transformation was significantly inhibited by THHta in JB6 Cl41 cells. THHta inhibits the growth of colon cancer cells in vitro in a significant dose-dependent manner. Compared to the control set, i.p. administration of THHta to xenograft mice significantly reduced both tumor weight and volume. Apoptosis induction of THHta was mediated by activation of caspase-3, PARP and inhibiting of Bcl-2, Bcl-xL and XIAP. ConclusionTHHta was effective in inhibiting tumor growth both in vitro and in vivo at less toxic concentrations by inducing apoptosis which suggested it could be developed as a potential anticancer agent.

Pulsed High-Intensity Focused Ultrasound Therapy Enhances Targeted Delivery of Cetuximab to Colon Cancer Xenograft Model in Mice

Our aim was to evaluate whether pulsed high-intensity focused ultrasound (HIFU) therapy enhances the effect of an epidermal growth factor receptor–targeted chemotherapeutic drug, cetuximab, in treating human colon cancer xenografts in a mouse model. Balb/c nude mice with subcutaneous xenografts of HT-29 cells were randomly categorized into control (n = 9), pulsed HIFU alone (n = 10), cetuximab monotherapy (n = 8) or combined pulsed HIFU and cetuximab therapy (n = 9) group. Cetuximab, pulsed HIFU therapy, or both were administered three times per week starting from day 8 after tumor cell injection. Based on tumor growth curves up to 34 days, the combination therapy group showed more suppressed tumor growth than all other groups (p < 0.05). The final relative tumor volumes were 5.4 ± 2.1, 5.2 ± 1.3, 4.8 ± 1.8, and 3.1 ± 0.9 for control, pulsed HIFU alone, cetuximab monotherapy, and combination therapy groups, respectively. In conclusion, pulsed HIFU therapy appears to enhance the anti-tumor effect of epidermal growth factor receptor–targeted cetuximab on human colon cancer xenograft models in mice.

Balancing the Pharmacokinetics and Pharmacodynamics of Interferon-α2b and Human Serum Albumin Fusion Protein by Proteolytic or Reductive Cleavage Increases Its in Vivo Therapeutic Efficacy

Human serum albumin (HSA) fusion (Albufusion) technology has evolved to be a general strategy to increase the in vivo half-lives of therapeutic proteins. However, because of the steric hindrance effect of HSA, conventional Albufusion technology improves the pharmacokinetics (PK) at the cost of pharmacodynamics (PD). To achieve balanced PK and PD of interferon-α2b (IFN-α2b) and HSA fusion protein, protease cleavage sites or disulfide linkage that enabled releasing of intact IFN-α2b with full activity was introduced between these two moieties. Nonreleasable and releasable fusion proteins showed similar cell surface receptor binding affinities; however, releasable fusion proteins exhibited release efficiency proportional increase of in vitro antiviral and antiproliferative activities. The release rate also had a profound impact on the in vivo pharmaceutical properties of fusion proteins. Releasable fusion proteins with intermediate release rate had the most balanced PK and PD, which translated into improved therapeutic efficacy in the HT29 human colon cancer xenograft model. Releasable Albufusion (rAlbufusion) allows tailored design of the PK/PD profile and greatly extends the utility of conventional Albufusion technology.