ISL2 is a putative tumor suppressor whose epigenetic silencing reprograms the metabolism of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDA) cells reprogram their transcriptional and metabolic programs to survive the nutrient-poor tumor microenvironment. Through in vivo CRISPR screening, we discovered islet-2 (ISL2) as a candidate tumor suppressor that modulates aggressive PDA growth. Notably, ISL2, a nuclear and chromatin-associated transcription factor, is epigenetically silenced in PDA tumors and high promoter DNA methylation or its reduced expression correlates with poor patient survival. The exogenous ISL2 expression or CRISPR-mediated upregulation of the endogenous loci reduces cell proliferation. Mechanistically, ISL2 regulates the expression of metabolic genes, and its depletion increases oxidative phosphorylation (OXPHOS). As such, ISL2-depleted human PDA cells are sensitive to the inhibitors of mitochondrial complex I in vitro and in vivo. Spatial transcriptomic analysis shows heterogeneous intratumoral ISL2 expression, which correlates with the expression of critical metabolic genes. These findings nominate ISL2 as a putative tumor suppressor whose inactivation leads to increased mitochondrial metabolism that may be exploitable therapeutically.

The sister-chromatid exchange and acetylcholine esterase enzyme levels among patients with insecticide intoxication in the Cukurova region, Turkey.

This study included 45 patients with intentional insecticide intoxication and 21 with accidental intoxication who were treated at the First-Aid and Emergency Department of Balcali Hospital at the Faculty of Medicine in the Cukurova University, Adana, Turkey, while the control group consisted of 25 people selected from university personnel known to be healthy. Patients with a history of X-ray exposure in the last 6 months or of any virus disease as well as continuous drug users and smokers were excluded, leaving a total of 49 patients. Acetylcholine esterase (Pseudocholinesterase) enzyme (AchE), sister-chromatid exchanges (SCE), the mitotic index (MI), and the replication index (RI) were evaluated. Blood samples were cultured for SCE evaluation and sera separated for AchE levels. Insecticide exposure was generally intentional for suicide in adolescents and at older ages, but accidental for children. AchE levels were found to be significantly lower in organophosphorus (OP) and carbamated (CB) insecticide poisoning groups in comparison with the control group (p<0.001), while the pyrethroid (PY) group was not statistically different for the AchE effect (p>0.05). SCE was found to be significantly higher in OP and CB groups (p<0.001), while the PY and control groups were statistically similar for SCE levels (p>0.05). This study showed an increase in SCE in response to orally ingested insecticides. These findings indicate that insecticide exposure results in cell abnormalities, with resulting impediments to the division and replication of cells, as suggested by MI decreases and RI increases, while the speed of the division cycles of stimulated cells increases.