KDM5D Histone Demethylase Identifies Platinum-Tolerant Head and Neck Cancer Cells Vulnerable to Mitotic Catastrophe.

Head and neck squamous cell carcinoma (HNSCC) is a major contributor to cancer incidence globally and is currently managed by surgical resection followed by adjuvant chemoradiotherapy. However, local recurrence is the major cause of mortality, indicating the emergence of drug-tolerant persister cells. A specific histone demethylase, namely lysine-specific demethylase 5D (KDM5D), is overexpressed in diverse types of cancers and involved in cancer cell cycle regulation. However, the role of KDM5D in the development of cisplatin-tolerant persister cells remains unexplored. Here, we demonstrated that KDM5D contributes to the development of persister cells. Aurora Kinase B (AURKB) disruption affected the vulnerability of persister cells in a mitotic catastrophe-dependent manner. Comprehensive in silico, in vitro, and in vivo experiments were performed. KDM5D expression was upregulated in HNSCC tumor cells, cancer stem cells, and cisplatin-resistant cells with biologically distinct signaling alterations. In an HNSCC cohort, high KDM5D expression was associated with a poor response to platinum treatment and early disease recurrence. KDM5D knockdown reduced the tolerance of persister cells to platinum agents and caused marked cell cycle deregulation, including the loss of DNA damage prevention, and abnormal mitosis-enhanced cell cycle arrest. By modulating mRNA levels of AURKB, KDM5D promoted the generation of platinum-tolerant persister cells in vitro, leading to the identification of the KDM5D/AURKB axis, which regulates cancer stemness and drug tolerance of HNSCC. Treatment with an AURKB inhibitor, namely barasertib, resulted in a lethal consequence of mitotic catastrophe in HNSCC persister cells. The cotreatment of cisplatin and barasertib suppressed tumor growth in the tumor mouse model. Thus, KDM5D might be involved in the development of persister cells, and AURKB disruption can overcome tolerance to platinum treatment in HNSCC.

Obstructive jaundice alters LFA-1alpha expression in rat small intestine.

Translocation of bacteria and endotoxtin has long been documented in obstructive jaundice, and altered intestinal barrier function is considered to be one of the important mechanisms for this phenomenon. The regulation of gastrointestinal mucosal response to injury is thus of important clinical as well as biological relevance. Integrins play a critical role in enterocyte migration, which is essential to mucosal healing. This study is designed to evaluate the integrins status in obstructive jaundice. Male Sprague-Dawley rats (N = 37) were randomized to three groups. Group 1 (N = 12) underwent common bile duct ligation (CBDL), group 2 (N = 12) underwent common bile duct ligation with oral glutamine administration (CBDL + G), and group 3 (N = 13) underwent a sham operation (sham control). After seven days, segments of proximal jejunum and distal ileum were harvested, and cell surface immunohistochemical expression of LFA-1alpha and VLA-6 were evaluated and recorded. The staining intensities were graded on a scale of 0-4. Comparisons among the three groups were performed. There was no significant difference in VLA-6 staining on small intestine among the three groups (P > 0.05). There was also no significant difference in LFA-1alpha staining the on jejunum between group 1 (CBDL) and group 3 (sham control) (P > 0.05). However, the LFA-1alpha staining on the ileum in group 1 (CBDL) significantly decreased when compared with group 3 (sham control) (P = 0.008). With oral glutamine administration (0.2 g/kg body weight, once daily), LFA-1alpha staining on the ileum was significantly restored in group 2 (CBDL + G). In conclusion, obstructive jaundice for one week down-regulates LFA-1alpha expression on rat ileum. With oral glutamine administration, such down-regulation of LFA-1alpha expression on rat ileum can be restored. Such a phenomenon is intriguing and deserves further evaluation and elucidation.

Effect of bile acid replacement on endotoxin-induced tumor necrosis factor-alpha production in obstructive jaundice.

There is a high incidence of perioperative morbidity and mortality in patients with obstructive jaundice due to sepsis. Tumor necrosis factor-a (TNF-alpha) is considered a crucial mediator in inducing and processing the inflammatory cascade. We hypothesize that obstructive jaundice leads to an increased endotoxin-induced TNF-alpha production and that intestinal bile acid replacement can prevent this phenomenon. Sprague-Dawley rats were randomized to three groups of 12 animals each. Group 1 underwent common bile duct ligation (CBDL) with oral intestinal bile acid (deoxycholic acid 5 mg/100 g body weight/3 times daily) replacement (CBDL + bile acid); group 2 underwent common bile duct ligation with the same amount of normal saline replacement orally (CBDL + saline); and group 3 underwent a sham operation (sham control). After 2 days, endotoxin was given to the animals, and after 90 minutes, tissues (liver and lung) and blood were collected for checking the TNF-alpha levels and biochemical analyses. Comparisons among these three groups were performed and recorded. While serum and tissue (liver and lung) TNF-alpha levels of group 2 (CBDL + saline) were significantly increased after endotoxin challenge, these elevations were reduced to control levels (sham control) following oral replacement of intestinal bile acid (CBDL + bile acid). Obstructive jaundice leads to an increased endotoxin-induced TNF-alpha production and intestinal bile acid replacement can inhibit this phenomenon.