In vivo anticancer activity of a rhodium metalloinsertor in the HCT116 xenograft tumor model

Mismatch repair (MMR) deficiencies are a hallmark of various cancers causing accumulation of DNA mutations and mismatches, which often results in chemotherapy resistance. Metalloinsertor complexes, including [Rh(chrysi)(phen)(PPO)]Cl₂ (Rh-PPO), specifically target DNA mismatches and selectively induce cytotoxicity within MMR-deficient cells. Here, we present an in vivo analysis of Rh-PPO, our most potent metalloinsertor. Studies with HCT116 xenograft tumors revealed a 25% reduction in tumor volume and 12% increase in survival with metalloinsertor treatment (1 mg/kg; nine intraperitoneal doses over 20 d). When compared to oxaliplatin, Rh-PPO displays ninefold higher potency at tumor sites. Pharmacokinetic studies revealed rapid absorption of Rh-PPO in plasma with notable accumulation in the liver compared to tumors. Additionally, intratumoral metalloinsertor administration resulted in enhanced anticancer effects, pointing to a need for more selective delivery methods. Overall, these data show that Rh-PPO inhibits xenograft tumor growth, supporting the strategy of using Rh-PPO as a chemotherapeutic targeted to MMR-deficient cancers

In vivo anticancer activity of a rhodium metalloinsertor in the HCT116 xenograft tumor model

Mismatch repair (MMR) deficiencies are a hallmark of various cancers causing accumulation of DNA mutations and mismatches, which often results in chemotherapy resistance. Metalloinsertor complexes, including [Rh(chrysi)(phen)(PPO)]Cl₂ (Rh-PPO), specifically target DNA mismatches and selectively induce cytotoxicity within MMR-deficient cells. Here, we present an in vivo analysis of Rh-PPO, our most potent metalloinsertor. Studies with HCT116 xenograft tumors revealed a 25% reduction in tumor volume and 12% increase in survival with metalloinsertor treatment (1 mg/kg; nine intraperitoneal doses over 20 d). When compared to oxaliplatin, Rh-PPO displays ninefold higher potency at tumor sites. Pharmacokinetic studies revealed rapid absorption of Rh-PPO in plasma with notable accumulation in the liver compared to tumors. Additionally, intratumoral metalloinsertor administration resulted in enhanced anticancer effects, pointing to a need for more selective delivery methods. Overall, these data show that Rh-PPO inhibits xenograft tumor growth, supporting the strategy of using Rh-PPO as a chemotherapeutic targeted to MMR-deficient cancers

Everolimus Exposure as a Predictor of Toxicity in Renal Cell Cancer Patients in the Adjuvant Setting: Results of a Pharmacokinetic Analysis for SWOG S0931 (EVEREST), a Phase III Study (NCT01120249).

BackgroundS0931 is assessing recurrence-free survival in renal cell carcinoma (RCC) patients randomized to receive everolimus (EVE) versus placebo for one year following nephrectomy. Due to a higher than expected dropout rate, we assessed EVE trough levels in the adjuvant setting to evaluate the relationship between EVE exposure and probability of toxicity.MethodsPatients received 10 mg daily EVE for nine 6-week cycles. Pre-dose whole blood samples were collected pre-cycle 2 and pre-cycle 3 and analyzed for EVE. Patients with pre-cycle 2 and/or pre-cycle 3 EVE results were used in the analysis. Patients were segregated into quartiles (Q) based on EVE levels and logistic regression was used to model the most common adverse event outcomes using EVE trough as a predictor. Hazard and odds ratios were adjusted for age, BMI and performance status.ResultsA total of 467 patients were included in this analysis. Quartiles normalized to an EVE dose of 10 mg/day were < 9.0, 9.0-12.9, 12.9-22.8, and > 22.8 ng/mL, respectively. EVE trough levels increased with increasing age (p < 0.001). Furthermore, EVE trough levels were higher in men than women (19.4 versus 15.4 ng/mL, p = 0.01). Risk of grade 2 + triglycerides was increased in Q2 and Q3 vs Q1 (OR = 2.08; p = 0.02 and OR = 2.63; p = 0.002). Risk of grade 2 + rash was increased in Q2 and Q4 vs Q1 (OR = 2.99; p = 0.01 and OR = 2.90; p = 0.02). There was also an increased risk of any grade 3 + tox in Q2 vs Q1 (OR = 1.71; p = 0.05).ConclusionsWe identified significant gender and age-related differences in EVE trough levels in patients receiving adjuvant treatment for RCC. Furthermore, our analysis identified significant associations between EVE exposure and probability of toxicity

Single-dose pharmacokinetic and toxicity analysis of pyrrole–imidazole polyamides in mice

Purpose: Pyrrole–imidazole (Py-Im) polyamides are programmable, sequence-specific DNA minor groove–binding ligands. Previous work in cell culture has shown that various polyamides can be used to modulate the transcriptional programs of oncogenic transcription factors. In this study, two hairpin polyamides with demonstrated activity against androgen receptor signaling in cell culture were administered to mice to characterize their pharmacokinetic properties. Methods: Py-Im polyamides were administered intravenously by tail vein injection. Plasma, urine, and fecal samples were collected over a 24-h period. Liver, kidney, and lung samples were collected postmortem. Concentrations of the administered polyamide in the plasma, excretion, and tissue samples were measured using LC/MS/MS. The biodistribution data were analyzed by both non-compartmental and compartmental pharmacokinetic models. Animal toxicity experiments were also performed by monitoring weight loss after a single subcutaneous (SC) injection of either polyamide. Results: The biodistribution profiles of both compounds exhibited rapid localization to the liver, kidneys, and lungs upon injection. Plasma distribution of the two compounds showed distinct differences in the rate of clearance, the volume of distribution, and the AUCs. These two compounds also have markedly different toxicities after SC injection in mice. Conclusions: The variations in pharmacokinetics and toxicity in vivo stem from a minor chemical modification that is also correlated with differing potency in cell culture. The results obtained in this study could provide a structural basis for further improvement of polyamide activity both in cell culture and in animal models

Quantitative Evaluation of Intraventricular Delivery of Therapeutic Neural Stem Cells to Orthotopic Glioma

Neural stem cells (NSCs) are inherently tumor-tropic, which allows them to migrate through normal tissue and selectively localize to invasive tumor sites in the brain. We have engineered a clonal, immortalized allogeneic NSC line (HB1.F3.CD21; CD-NSCs) that maintains its stem-like properties, a normal karyotype and is HLA Class II negative. It is genetically and functionally stable over time and multiple passages, and has demonstrated safety in phase I glioma trials. These properties enable the production of an “off-the-shelf” therapy that can be readily available for patient treatment. There are multiple factors contributing to stem cell tumor-tropism, and much remains to be elucidated. The route of NSC delivery and the distribution of NSCs at tumor sites are key factors in the development of effective cell-based therapies. Stem cells can be engineered to deliver and/or produce many different therapeutic agents, including prodrug activating enzymes (which locally convert systemically administered prodrugs to active chemotherapeutic agents); oncolytic viruses; tumor-targeted antibodies; therapeutic nanoparticles; and extracellular vesicles that contain therapeutic oligonucleotides. By targeting these therapeutics selectively to tumor foci, we aim to minimize toxicity to normal tissues and maximize therapeutic benefits. In this manuscript, we demonstrate that NSCs administered via intracerebral/ventricular (IVEN) routes can migrate efficiently toward single or multiple tumor foci. IVEN delivery will enable repeat administrations for patients through an Ommaya reservoir, potentially resulting in improved therapeutic outcomes. In our preclinical studies using various glioma lines, we have quantified NSC migration and distribution in mouse brains and have found robust migration of our clinically relevant HB1.F3.CD21 NSC line toward invasive tumor foci, irrespective of their origin. These results establish proof-of-concept and demonstrate the potential of developing a multitude of therapeutic options using modified NSCs

8-chloro-adenosine activity in FLT3-ITD acute myeloid leukemia

Nucleoside analogs represent the backbone of several distinct chemotherapy regimens for acute myeloid leukemia (AML) and combination with tyrosine kinase inhibitors has improved survival of AML patients, including those harboring the poor-risk FLT3-ITD mutation. Although these compounds are effective in killing proliferating blasts, they lack activity against quiescent leukemia stem cells (LSCs), which contributes to initial treatment refractoriness or subsequent disease relapse. The reagent 8-chloro-adenosine (8-Cl-Ado) is a ribose-containing, RNA-directed nucleoside analog that is incorporated into newly transcribed RNA rather than in DNA, causing inhibition of RNA transcription. In this report, we demonstrate antileukemic activities of 8-Cl-Ado in vitro and in vivo and provide mechanistic insight into the mode of action of 8-Cl-Ado in AML. 8-Cl-Ado markedly induced apoptosis in LSC, with negligible effects on normal stem cells. 8-Cl-Ado was particularly effective against AML cell lines and primary AML blast cells harboring the FLT3-ITD mutation. FLT3-ITD is associated with high expression of miR-155. Furthermore, we demonstrate that 8-Cl-Ado inhibits miR-155 expression levels accompanied by induction of DNA-damage and suppression of cell proliferation, through regulation of miR-155/ErbB3 binding protein 1(Ebp1)/p53/PCNA signaling. Finally, we determined that combined treatment of NSG mice engrafted with FLT3-ITD (+) MV4-11 AML cells with 8-Cl-Ado and the FLT3 inhibitor AC220 (quizartinib) synergistically enhanced survival, compared with that of mice treated with the individual drugs, suggesting a potentially effective approach for FLT3-ITD AML patients.Peer reviewe

Assessing and improving specificity of rhodium metalloinstertors in targeting MMR deficient cancer

Mismatch repair (MMR) deficiencies are a hallmark for 16% of all solid tumors and 80% of hereditary nonpolyposis colon cancers, and many patients with these types of malignancies are resistant to current oncol. treatments. Our lab. has conducted much work to develop mols. able to target the mismatches that result from MMR deficient cancers selectively. By incorporating particularly wide, arom., ancillary ligands, our Rh complexes are able to detect thermodynamically destabilized mismatch sites via a binding mode known as metalloinsertion, in which the inserting ligand binds DNA via the minor groove and results in ejection of the destabilized mismatched base pairs. We hypothesize that the complex binding site is later recognized as a lesion by the DNA repair machinery, which ultimately induces cytotoxicity. Our lab. evaluates different metalloinsertor complexes by comparing their biol. effects on mismatch repair proficient and deficient human colorectal cancer cell lines (HCT116). Currently, our most promising Rh complex [Rh(phen)(chrysi)( 2-(Pyridine-2-yl)propan-2-ol)]^(2+) (Rh-PPO) involves a unique rhodium-oxygen bond coordination with a puckered 5,6-chrysenequinone diimine inserting ligand. The complex displays submicromolar potency and can significantly differentiate the biol. activity between MMR -proficient and -deficient cell lines. Research in the lab has focused on further assessing Rh-PPO's promise as a chemotherapeutic by conducting in vivo pharmacokinetic and efficacy studies within mice. These animal studies have given insight into the best tolerated dose levels and administration routes, the impact of Rh-PPO treatment on mouse survival, and the chem. stability of Rh-PPO in vivo. These efforts have further validated the potential use of Rh-PPO as a targeted therapeutic for MMR deficient cancers

Assessing and improving specificity of rhodium metalloinstertors in targeting MMR deficient cancer

Mismatch repair (MMR) deficiencies are a hallmark for 16% of all solid tumors and 80% of hereditary nonpolyposis colon cancers, and many patients with these types of malignancies are resistant to current oncol. treatments. Our lab. has conducted much work to develop mols. able to target the mismatches that result from MMR deficient cancers selectively. By incorporating particularly wide, arom., ancillary ligands, our Rh complexes are able to detect thermodynamically destabilized mismatch sites via a binding mode known as metalloinsertion, in which the inserting ligand binds DNA via the minor groove and results in ejection of the destabilized mismatched base pairs. We hypothesize that the complex binding site is later recognized as a lesion by the DNA repair machinery, which ultimately induces cytotoxicity. Our lab. evaluates different metalloinsertor complexes by comparing their biol. effects on mismatch repair proficient and deficient human colorectal cancer cell lines (HCT116). Currently, our most promising Rh complex [Rh(phen)(chrysi)( 2-(Pyridine-2-yl)propan-2-ol)]^(2+) (Rh-PPO) involves a unique rhodium-oxygen bond coordination with a puckered 5,6-chrysenequinone diimine inserting ligand. The complex displays submicromolar potency and can significantly differentiate the biol. activity between MMR -proficient and -deficient cell lines. Research in the lab has focused on further assessing Rh-PPO's promise as a chemotherapeutic by conducting in vivo pharmacokinetic and efficacy studies within mice. These animal studies have given insight into the best tolerated dose levels and administration routes, the impact of Rh-PPO treatment on mouse survival, and the chem. stability of Rh-PPO in vivo. These efforts have further validated the potential use of Rh-PPO as a targeted therapeutic for MMR deficient cancers