Analysis of anti-tumor effect and mechanism of GLS1 inhibitor CB-839 in colorectal cancer using a stroma-abundant tumor model.

BACKGROUND: Glutaminase 1 (GLS1), a key enzyme in glutamine metabolism in cancer cells, acts as a tumor promoter and could be a potential therapeutic target. CB-839, a GLS1-specific inhibitor, was developed recently. Herein, we aimed to elucidate the anti-tumor effects and mechanism of action of CB-839 in colorectal cancer (CRC). METHODS: Using the UCSC Xena public database, we evaluated GLS1 expression in various cancers. Immunostaining for GLS1 was performed on 154 surgically resected human CRC specimens. Subsequently, we examined the GLS1 mRNA expression levels in eight CRC cell lines and evaluated the association between GLS1 expression and CB-839 efficacy. To create a reproducible CRC model with abundant stroma and an allogeneic immune response, we co-transplanted CT26 and stem cells into BALB/c mice and treated them with CB-839. Finally, RNA sequencing of mouse tumors was performed. RESULTS: Database analysis showed higher GLS1 expression in CRC tissues than in normal colon tissues. Clinical samples from 114 of the 154 patients with CRC showed positive GLS1 expression. GLS1 expression in clinical CRC tissues correlated with vascular invasion. CB-839 treatment inhibited cancer cell proliferation depending on GLS1 expression in vitro and inhibited tumor growth and metastasis in the CRC mouse model. RNA sequencing revealed that CB-839 treatment inhibited stromal activation, tumor growth, migration, and angiogenesis. These findings were validated through in vitro and in vivo experiments and clinical specimen analysis. CONCLUSIONS: GLS1 expression in CRC plays important roles in tumor progression. CB-839 has inhibitory effects on cancer proliferation and the tumor microenvironment.

Long-term prognosis after endoscopic submucosal dissection for esophageal cancer in older adult patients.

BACKGROUND: The validity of endoscopic submucosal dissection (ESD) for esophageal squamous cell carcinoma (ESCC) in older individuals with comorbidities remains unclear. Therefore, this study evaluated the safety and efficacy of ESD and additional treatment for ESCC in older adult patients. METHODS: The clinicopathological characteristics and clinical outcomes of 398 consecutive older adult patients (≥ 65 years) with 505 lesions who underwent ESD for ESCC at the Hiroshima University Hospital between September 2007 and December 2019 were retrospectively evaluated. Additionally, the prognoses of 381 patients who were followed up for > 3 years were assessed. RESULTS: The mean patient age and procedure time were 73.1 ± 5.8 years and 77.1 ± 43.5 min, respectively. The histological en bloc resection rate was 98% (496/505). Postoperative stenosis, perforation, pneumonia, and delayed bleeding were conservatively treated in 82 (16%), 19 (4%), 15 (3%), and 5 (1%) patients, respectively. The 5-year overall and disease-specific survival rates were 78.9% and 98.0%, respectively (mean follow-up time: 71.1 ± 37.3 months). Multivariate analysis showed that age and the American Society of Anesthesiologists classification of physical status class ≥III (hazard ratio: 1.27; 95% confidence interval: 1.01-1.59, p = 0.0392) were independently associated with overall survival. A significantly lower overall survival rate was observed in the high-risk follow-up group than in the low-risk follow-up and high-risk additional treatment groups (p < 0.01). However, no significant difference in disease-specific survival was observed among the three groups. CONCLUSIONS: ESD is safe for ESCC treatment in patients aged ≥ 65 years. However, additional treatments should be considered based on the patient's general condition.

Predictive factors for esophageal stenosis in patients receiving prophylactic steroid therapy after endoscopic submucosal dissection for esophageal squamous cell carcinoma.

BACKGROUND: Methods to prevent esophageal stenosis (ES) after endoscopic submucosal dissection (ESD) for superficial esophageal squamous cell carcinoma (ESCC) have received increasing attention. Although steroid administration is a prophylactic treatment, the risk factors for ES during prophylactic steroid therapy remain unknown. Therefore, this study aimed to retrospectively evaluate the risk factors for refractory ES in patients administered prophylactic steroids after ESD for ESCC. METHODS: Among 795 patients with ESCC (854 lesions), 180 patients (211 lesions) administered local triamcinolone acetonide (TrA) and/or oral prednisolone were recruited for this study. We compared the total number of endoscopic balloon dilatation (EBD) procedures performed for post-ESD ES and clinical findings (tumor size, ESD history or chemoradiation therapy [CRT], entire circumferential resection, muscle layer damage, supplemental oral prednisolone administration, EBD with TrA injection, and additional CRT) between patients with refractory and non-refractory ES. EBD was continued until dysphagia resolved. We categorized cases requiring ≥ 8 EBD procedures as refractory postoperative stenosis and divided the lesions into two groups. RESULTS: Multivariate logistic regression analysis revealed that factors such as ESD history, CRT history, tumor size, and entire circumferential resection were independently associated with the development of refractory ES. The withdrawal rates of EBD at 3 years were 96.1% (52/53) and 58.5% (39/59) in the non-refractory and refractory groups, respectively. CONCLUSIONS: Our data suggest that entire circumferential resection and CRT history are risk factors for refractory post-ESD ES in ESCC, even with prophylactic steroid administration.

Value of autotaxin for hepatocellular carcinoma risk assessment in chronic hepatitis B patients treated with nucleos(t)ide analogs.

AIM: Autotaxin (ATX) is a newly identified liver fibrosis biomarker; however, its clinical usefulness remains unclear. Therefore, we analyzed the changes in patients with chronic hepatitis B virus infection treated with nucleos(t)ide analogs (NAs) to evaluate its usefulness. We also investigated the predictors of hepatocellular carcinoma development, including ATX, in patients with chronic hepatitis B based on their clinical characteristics. METHODS: This retrospective study included 179 patients with hepatitis B virus infection treated with NAs for >2 years. First, we measured the ATX levels before and up to 10 years after initiating entecavir (therapy for 88 patients whose serial ATX levels could be measured before and during entecavir therapy. Subsequently, for 179 patients whose ATX levels could be measured at the commencement of NAs, we examined the factors involved in developing hepatocellular carcinoma, including ATX. RESULTS: The ATX levels showed a gradual and significant decrease during the observation period of up to 10 years. Multivariable analysis showed that a baseline ATX/upper limits of normal ratio ≥1.214, age, and alkaline phosphatase levels were independent risk factors for hepatocellular carcinoma development. The combination of age and ATX/upper limits of normal ratio was used to stratify the high-risk groups for liver carcinogenesis. CONCLUSIONS: A decrease in ATX levels up to 10 years after the commencement of therapy suggested that ATX is a helpful biomarker in evaluating fibrosis in patients undergoing long-term NA therapy. Furthermore, this study showed that combining age and the baseline ATX/upper limits of normal ratio may help identify high-risk carcinogenesis groups.

Pexidartinib and Immune Checkpoint Inhibitors Combine to Activate Tumor Immunity in a Murine Colorectal Cancer Model by Depleting M2 Macrophages Differentiated by Cancer-Associated Fibroblasts.

Tumor-associated macrophages (TAMs) and cancer-associated fibroblasts (CAFs) are known to play supportive roles in tumor development and progression, but their interactions in colorectal cancer (CRC) remain unclear. Here, we investigated the effects of colon-cancer-derived CAFs on TAM differentiation, migration, and tumor immunity, both in vitro and in vivo. When co-cultured with monocytes, CAFs attracted monocytes and induced their differentiation into M2 macrophages. Immunohistology of surgically resected human CRC specimens and orthotopically transplanted mouse tumors revealed a correlation between numbers of CAFs and numbers of M2 macrophages. In a mouse model of CRC orthotopic transplantation, treatment with an inhibitor of the colony-stimulating factor-1 receptor (PLX3397) depleted M2 macrophages and increased CD8-positive T cells infiltrating the tumor nest. While this treatment had a minor effect on tumor growth, combining PLX3397 with anti-PD-1 antibody significantly reduced tumor growth. RNA-seq following combination therapy showed activation of tumor immunity. In summary, CAFs are involved in the induction and mobilization of M2 macrophage differentiation in the CRC tumor immune microenvironment, and the combination of cancer immunotherapy and PLX3397 may represent a novel therapeutic option for CRC.

Pazopanib-induced enteritis in a patient with renal cell carcinoma.

A 69-year-old woman presented to our department with the chief complaint of diarrhea. She had undergone left nephrectomy for renal cancer 14 years earlier. Three years earlier, metastasis was detected in the left retroperitoneal cavity, and pazopanib administration was initiated. In the 29th month after the start of chemotherapy, the patient developed diarrhea, and on the 31st month, computed tomography showed thickening of the intestinal wall. Colonoscopy revealed white villi, intramucosal hemorrhage in the terminal ileum, and rough inflammatory mucosa with inflammatory polyps extending from the transverse to the sigmoid colon. Suspecting pazopanib-induced enteritis, we discontinued the medication, and the diarrhea resolved within 3 days. On the 21st day after discontinuation, colonoscopy revealed that the inflammatory polyps had shrunk, and the inflammatory findings had improved. Biopsy of the white villi of the ileum revealed histiocytes. The patient resumed treatment with pazopanib at 400 mg/day and developed soft stool on the 7th day after resumption. Compared with other tyrosine-kinase inhibitor-induced enteritis cases, this case showed less bleeding and more extensive inflammatory findings. There are similarities as well as differences from cases of previously reported pazopanib-induced enteritis. The mechanisms and characteristics of this disease require further investigation.

Clinicopathological and genomic features of superficial esophageal squamous cell carcinomas in nondrinker, nonsmoker females.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is sometimes detected in non-drinker and non-smoker females who are considered to have very low risk of ESCC development in daily practice. This study examined the clinicopathological and genomic characteristics of ESCCs in females with no history of drinking and smoking. METHODS: The sample comprised 118 ESCC lesions occurring in 95 female patients who underwent endoscopic submucosal dissection at our department between January 2008 and December 2019. The patients were categorized into two groups: 51 lesions in 49 patients with no history of drinking and smoking (nondrinker/nonsmoker [NDNS] group) and 69 lesions in 45 patients with a history of drinking or smoking (drinker/smoker [DS] group). We analyzed the differences in clinicopathological and cancerous genomic characteristics between the groups. Significant genomic alterations were validated using immunohistochemistry. RESULTS: Multiple logistic regression revealed that older age, fewer multiple Lugol-voiding lesions (LVLs), and reflux esophagitis (RE) were independently associated with the occurrence of ESCCs in the NDNS group. ESCC lesions in the NDNS group were predominantly located in the mid-thoracic esophagus, posterior wall side, with 0-IIa, the aspect ratio of the lesion >2 (vertical/horizontal), and endoscopic keratinization. Genetic analysis showed that CDKN2A driver alterations were significantly more frequent and KMT2D alterations were significantly less frequent in the NDNS group than in the DS group. KMT2D alterations were strongly correlated with immunostaining. CONCLUSION: Older nondrinker, nonsmoker females with RE and fewer multiple LVLs may develop longitudinal 0-IIa ESCC with keratinization of the posterior wall of the mid-thoracic esophagus. ESCCs in nondrinker, nonsmoker females had fewer KMT2D alterations and more CDKN2A alterations, which may be a biomarker for treatment.