Abstract 841: Therapeutic targeting of cancer cells in the hypoxic microenvironment using an orally bioavailable small molecule inhibitor of carbonic anhydrase IX
Bibliographic record
Abstract
Abstract Carbonic anhydrase IX (CAIX) is a membrane-bound, hypoxia-inducible enzyme that is highly expressed in many types of solid tumors, is an independent marker of poor prognosis and functions as a critical component of the pH regulatory machinery required by hypoxic cancer cells for survival, invasion and metastasis. These attributes make CAIX an attractive therapeutic target for cancer therapy. The development of pharmacologic inhibitors that selectively target tumor-associated, extracellular carbonic anhydrases (CAs) without “off-target” inhibition of cytosolic isoforms is critical for their use as cancer therapeutics. Here, we characterize an orally bioavailable, highly selective small molecule inhibitor of CAIX and CAXII, SLC-0111, and investigate its efficacy when used as a monotherapy and in combination with conventional chemotherapy in vivo. SLC-0111 exhibited a favorable in vitro ADME profile, including IC50 values of >100 mM against most CYP isoforms, an IC50 for hERG inhibition of >30 mM and absence of mutagenic properties. Incubation of the compound with 67NR cells constitutively expressing human CAIX significantly suppressed, in a dose-dependent fashion, a drop in extracellular pH in a cell-based CAIX activity assay. The active compound was formulated as a self-emulsifying liquid for oral administration in vivo and evaluation of plasma levels showed good oral bioavailability of 40%. Toxicity studies involving repeat dosing by oral gavage for 7 days established maximum-tolerated doses in excess of 1,000 and 750 mg/kg for rats and dogs, respectively. Daily oral administration of SLC-0111 to mice harboring established MDA-MB-231 LM2-4 orthotopic human breast tumors, a model of hypoxic, CAIX-positive triple negative metastatic breast cancer, resulted in a significant, dose-dependent reduction in tumor growth, with 30% inhibition at a dose of 50 mg/kg, no toxicity and a 10-fold therapeutic window. Treatment also reduced viable tumor volume as determined by 18F-deoxyglucose uptake detected by positron emission tomography. Furthermore, treatment of mice with SLC-0111 in combination with paclitaxel resulted in significantly reduced tumor growth compared to either treatment administered alone, with no additional toxicity and plasma levels of SLC-0111 similar to those observed with its use as a monotherapy. Plasma levels of SLC-0111 showed dose proportionality and analysis of tumor levels demonstrated a greater than proportional relationship, with a 4-fold increase in dose (25-100 mg/kg) resulting in more than a 13-fold increase in tumor levels of the compound. Collectively, these data demonstrate the potential utility of SLC-0111 as a safe, target-specific inhibitor of CAIX for the treatment of cancer, particularly in combination with conventional chemotherapy. Citation Format: Paul C. McDonald, Jasbinder Sanghera, Madhu Singh, Yuanmei Lou, Marylou Vallejo, Claudiu T. Supuran, Shoukat Dedhar. Therapeutic targeting of cancer cells in the hypoxic microenvironment using an orally bioavailable small molecule inhibitor of carbonic anhydrase IX. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 841. doi:10.1158/1538-7445.AM2014-841
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".