ALDH1L2 regulation of formate, formyl-methionine, and ROS controls cancer cell migration and metastasis

Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes-aldehyde dehydrogenase 1 family member 2 (ALDH1L2)-produces NADPH by catabolizing 10-formyl-THF into CO2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling.

Diagnostic strategies using physical examination are minimally useful in defining carpal tunnel syndrome in population-based research studies

OBJECTIVE

We evaluated the utility of physical examination manoeuvres in the prediction of carpal tunnel syndrome (CTS) in a population-based research study.

METHODS

We studied a cohort of 1108 newly employed workers in several industries. Each worker completed a symptom questionnaire, a structured physical examination and nerve conduction study. For each hand, our CTS case definition required both median nerve conduction abnormality and symptoms classified as "classic" or "probable" on a hand diagram. We calculated the positive predictive values and likelihood ratios for physical examination manoeuvres in subjects with and without symptoms.

RESULTS

The prevalence of CTS in our cohort was 1.2% for the right hand and 1.0% for the left hand. The likelihood ratios of a positive test for physical provocative tests ranged from 2.0 to 3.3, and those of a negative test from 0.3 to 0.9. The post-test probability of positive testing was <50% for all strategies tested.

CONCLUSION

Our study found that physical examination, alone or in combination with symptoms, was not predictive of CTS in a working population. We suggest using specific symptoms as a first-level screening tool, and nerve conduction study as a confirmatory test, as a case definition strategy in research settings.

Phase II trial of DJ-927, an oral tubulin depolymerization inhibitor, in the treatment of metastatic colorectal cancer

3591

Background: DJ-927, a novel oral tubulin depolymerization inhibitor, causes apoptosis and DNA cell division arrest. It is not a substrate for the MDR and has excellent activity in preclinical colorectal cancer models. Methods: We are conducting a two-stage, multi-center, phase II trial to assess the efficacy of DJ-927 administered initially as second-line therapy following failure of irinotecan or oxaliplatin based therapy (n= 39). DJ-927 is given as a single oral dose on day 1 of a 21-day cycle at a dose range of 27 - 35 mg/m2. Results: Thirty-nine patients were enrolled, including 14 with prior irinotecan based therapy and 25 who had received prior oxaliplatin therapy. The median age was 56 years (range: 30–87) and the median ECOG PS at baseline was 1 (range: 0–2). A total of 155 courses (range: 1–24) have been administered with a median of 2 courses. Nine patients required dose reduction due to toxicity. Thirty-seven patients were evaluable for efficacy. There were 2 CRs and 2 PRs (10.3%) reported that were confirmed as per RECIST criteria. Fourteen patients (35.9%) had SD, including 6 patients (15.4%) with SD >12 weeks. The most common Grade 3 or 4 AEs were neutropenia (48.7%), fatigue (10.3%), neuropathy (7.8%), and nausea (5.0%).Six patients experienced febrile neutropenia, all requiring hospitalization but tolerated treatment with subsequent dose reduction. There were 13 episodes (33.3%) of peripheral neuropathy reported; however, only 3 (7.8%) were grade 3 or 4. Six patients withdrew due to adverse events. Conclusions: The results of this study indicate activity of DJ-927 as second line therapy in patients with metastatic colorectal cancer. Severe toxicity was generally limited to reversible neutropenia and peripheral neuropathy. This novel oral agent is well tolerated and warrants further evaluation in combination with other active agents.

[Table: see text]