Akira Inoue

In pancreatic cancer, cancer stem-like cells (CSCs) contribute to tumor initiation, reduced drug sensitivity, and recurrence. Limited strategies are currently available to target this cell population. Here we used a proteasome-low CSC enrichment system to identify microRNAs that negatively regulate CSC-like properties. From PANC-1 cells expressing a ZsGreen–ODC degron reporter, a proteasome-low population was isolated through sequential fluorescence-activated cell sorting of ZsGreen-positive cells. Molecular and functional analyses confirmed the CSC-like phenotype of this cell population. Integrated in silico analysis was used to select 31 microRNAs predicted to target CSC-related molecules, which were then evaluated by in vitro viability-based screening to identify candidates that selectively suppressed the viability of CSC-like cells, relative to non-CSCs. Moreover, comprehensive miRNA expression profiling revealed that miR-136-5p was downregulated in the CSC-like population and was therefore selected for further analysis. Mechanistically, miR-136-5p directly targets the 3′ untranslated region of DCLK1 and reduces its expression, with a greater reduction in the short isoform. Finally, in a CSC-derived xenograft mouse model, systemic delivery of miR-136-5p using super carbonate apatite nanoparticles significantly suppressed tumor growth. Taken together, these findings suggest that miR-136-5p restoration may provide a therapeutic approach for targeting CSC-driven tumor growth in pancreatic cancer.

Background/Aim: Pancreatic cancer remains one of the most lethal malignancies, with limited therapeutic options and an extremely poor prognosis. MicroRNAs (miRNAs), which regulate gene expression at the post-transcriptional level, have emerged as promising candidates for next-generation cancer therapeutics. The purpose of this study is to clarify the feasibility of miR-4711 as a potential therapeutic option against pancreatic cancer. Materials and Methods: The effects of miR-4711-5p were examined in pancreatic cancer cell lines with respect to cell proliferation, apoptosis, cancer stemness, cell cycle progression, and invasive capacity. RNA sequencing and in silico analyses were performed to identify potential target genes of miR-4711-5p. For in vivo safety evaluation, miR-4711-5p was formulated with super carbonate apatite, a delivery vehicle that is already amenable to large-scale production, and administered to cynomolgus monkeys. A nucleic acid dose equivalent to 10 times the effective dose observed in prior mouse efficacy studies was used. General clinical conditions, body weight, food consumption, ophthalmologic findings, electrocardiography, blood pressure, hematological and biochemical parameters, and histopathological changes were systematically assessed. Results: miR-4711-5p significantly suppressed cancer stemness, cell proliferation, and invasion, while inducing apoptosis and delaying cell cycle progression in pancreatic cancer cells. RNA sequencing and bioinformatic analyses identified MET, CTSA, and ANO1 as potential target genes of miR-4711-5p. In the cynomolgus monkey study, administration of miR-4711-5p formulated with super carbonate apatite resulted in no apparent differences compared with the control group in body weight, clinical observations, laboratory parameters, or histopathological findings, indicating the absence of treatment-related adverse effects even at a supra-therapeutic dose. Conclusions: These findings demonstrate that miR-4711-5p exerts potent antitumor effects against pancreatic cancer cells while exhibiting a favorable safety profile in a non-human primate model. Collectively, this study provides strong preclinical evidence supporting miR-4711-5p as a novel and safe therapeutic strategy for pancreatic cancer and represents an important step toward clinical application.

Background: High microsatellite instability (MSI-H) is an established prognostic marker in various cancers, including colorectal, gastric, and endometrial cancers. However, comprehensive real-world data from universal screening in Asian populations remain limited. We aimed to evaluate the clinicopathological and prognostic impact of MSI-H status in Japanese patients with colorectal cancer (CRC). Methods: This retrospective cohort study was conducted at Osaka General Medical Center, Japan. A total of 346 consecutive patients with CRC who underwent MSI testing between January 2021 and December 2022 were retrospectively analyzed. MSI status and associated clinicopathological features were assessed. Overall survival (OS) and recurrence-free survival (RFS) were analyzed using Kaplan–Meier survival curves and Cox regression models. Results: Among the 346 patients, 29 (8.4%) had MSI-H tumors, which were more frequently right-sided ( p p RAS mutations ( p = 0.024) and more BRAF mutations ( p p = 0.40) or OS (HR, 0.64; 95% CI, 0.30–1.58; p = 0.78) between patients with MSI-H and non–MSI-H tumors. Multivariate analysis identified MSI-H as a potential independent predictor of favorable OS (HR, 0.07; 95% CI, 0.005–0.90; p = 0.04), whereas BRAF mutations were associated with poor OS (HR, 7.39; 95% CI, 1.32–41.50; p = 0.02). Conclusions: This real-world study suggests that MSI-H status is associated with distinct clinicopathological characteristics and may be associated with improved overall survival in Japanese patients with CRC undergoing universal MSI screening. These findings support the clinical relevance of MSI testing in routine clinical practice and highlight the need for further validation in a larger cohort.

Aim: Clinical benefits of robot‐assisted colectomy over laparoscopic colectomy for colon cancer remain uncertain, and real‐world data are limited. We evaluated the short‐term outcomes of robot‐assisted colectomy versus laparoscopic colectomy in patients with colon cancer. Methods: This single‐center, retrospective cohort study evaluated patients who underwent minimally invasive colectomies for colon cancer at Osaka General Medical Center from January 2014 to November 2024. Short‐term outcomes were compared after 1:1 propensity score matching to minimize confounding by indication. Results: In total, 480 patients underwent laparoscopic colectomies and 282 underwent robot‐assisted colectomies, with 218 matched pairs. Baseline characteristics were well‐balanced. Surgical procedure distribution was similar between the groups ( P = 0.897). Mean operative times were significantly longer (212 vs. 200 min, P = 0.040), mean intraoperative blood loss was significantly lower (22.8 vs. 37.5 mL, P < 0.001), rates of conversion to open surgery were significantly lower (0.0% vs. 2.3%, P = 0.026), and mean hospital stays were significantly shorter (7.0 vs. 11.3 d, P < 0.001) in the robot‐assisted colectomy group. The number of lymph node dissections ( P = 0.27) and local R0 resection rates ( P = 0.34) were comparable. Overall complication rates were significantly lower in the robot‐assisted colectomies (11.0% vs. 17.9%, P = 0.007), whereas clinically meaningful complication rates (Clavien–Dindo grades ≥ II) were comparable ( P = 0.150). Conclusions: These findings provide real‐world data supporting the feasibility of robot‐assisted colectomy for colon cancer treatment. Further research should evaluate the long‐term oncologic outcomes and cost‐effectiveness.

Background/Aim: Pancreatic cancer has a poor prognosis, with a 5-year survival rate of only 9%. Thus, there is an urgent need to develop effective cancer therapeutics for this disease. It is expected that nucleic acid therapeutics will be a next-generation cancer treatment. We previously reported that MIRTX – a complementary strand of miR-29b-1-5p (the passenger sequence of miR-29b) – exerts strong anti-tumor effects in colorectal cancer cells. Here we investigated the anti-tumor effects of MIRTX, compared to those of the guide sequence of miR-29b (miR-29b-3p), in pancreatic cancer cells. Materials and Methods: We evaluated how treatment with MIRTX and miR-29b-3p affected cell proliferation, cell cycle, apoptosis, and invasion in pancreatic cancer cell lines (Panc-1, SUIT-2, and BxPC-3). We also performed RNA-seq and in silico analyses to explore novel target genes of MIRTX. Results: Compared to miR-29b-3p, MIRTX strongly suppressed cell proliferation and invasion, delayed cell cycle progression, and induced apoptosis in pancreatic cancer cells. RNA-seq and in silico prediction identified the genes encoding cyclin A2, cyclin B2, and NCAPD3 as potential candidate targets of MIRTX. Conclusion: MIRTX is a potential therapeutic miRNA in pancreatic cancer cells.

Colorectal cancer (CRC) with liver-only metastases remains a significant clinical challenge owing to its high recurrence rate, even after curative hepatectomy. Despite advancements in surgical techniques and systemic therapies, identifying patients at elevated risk of recurrence is crucial for optimizing long-term outcomes. Circulating tumor DNA (ctDNA) is a biomarker for minimal residual disease and recurrence risk assessment. We hypothesize that plasma-only ctDNA assays using the Plasma-Safe-SeqS platform can enable early recurrence detection and guide postoperative management, including adjuvant chemotherapy. This single-center, prospective observational study will enroll 10 patients with histologically confirmed CRC and liver-only metastases undergoing curative hepatectomy. Plasma samples are collected preoperatively and at predefined intervals postoperatively (4, 12, 24, 36, and 48 weeks) to monitor ctDNA levels using a highly sensitive 14-gene panel designed to detect tumor-specific mutations. Mutant allele frequencies as low as 0.1% are detected using the Plasma-Safe-SeqS platform. The primary endpoint is the interval between ctDNA detection and clinically confirmed recurrence. The secondary endpoints include mutation concordance between pre- and postoperative samples, 3-year disease-free survival, 5-year overall survival, and correlations with clinicopathological features. Kaplan–Meier estimates and Cox proportional hazards models are used for statistical analyses. To our knowledge, this is the first study to utilize a 14-gene panel with Plasma-Safe-SeqS technology for ctDNA analysis in patients with CRC liver metastases following curative hepatectomy. By eliminating the need for tumor tissue, this plasma-only approach simplifies diagnostics and mitigates logistical barriers, including prolonged turnaround times associated with tumor-informed assays. We aim to validate ctDNA as a reliable biomarker for early recurrence detection. Furthermore, we may provide valuable insights into optimizing adjuvant chemotherapy strategies by identifying high-risk patients who may benefit from treatment while sparing low-risk patients from unnecessary toxicity. These findings may advance personalized postoperative care and enhance long-term outcomes in this patient population. Trial registration The study is registered in accordance with the International Committee of Medical Journal Editors (ICMJE) guidelines under the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR). The registry name is UMIN-CTR. The registration number is UMIN000057128. Trial details are available upon request.

Background The survival benefit of adjuvant chemotherapy after curative hepatectomy for colorectal cancer (CRC) liver metastases remains controversial. This retrospective study aimed to evaluate the efficacy of adjuvant chemotherapy in improving recurrence-free survival (RFS) and overall survival (OS) in patients who underwent curative hepatectomy for CRC liver metastases at a tertiary medical center. Methods We retrospectively analyzed clinicopathological factors in 89 patients (surgery alone, n = 63; adjuvant chemotherapy, n = 26) who underwent curative hepatectomy for CRC liver metastases from January 2010 to December 2022. Patients who received neoadjuvant therapy or prior hepatectomy were excluded to minimize patient heterogeneity. Multivariate analysis using Cox proportional hazards regression was conducted to assess the independent effect of adjuvant therapy on RFS and OS. Results The 3-year RFS rates were 22.6% in the surgery alone group and 29.6% in the adjuvant chemotherapy group (hazard ratio, 0.71; 95% confidence interval, 0.43-1.21; p = 0.102). The 3-year OS rates were 72.3% in the surgery alone group and 88.5% in the adjuvant chemotherapy group (hazard ratio, 0.59; 95% confidence interval, 0.29-1.25; p = 0.17). Univariate analyses showed that the number of liver metastases (> 2) was significantly associated with poorer OS (hazard ratio, 2.44; 95% confidence interval, 1.11-5.37; p = 0.027). Additionally, multivariate analyses showed that the addition of adjuvant chemotherapy was significantly associated with improved OS (hazard ratio, 0.23; 95% confidence interval, 0.07-0.81; p = 0.021). Conclusions Adjuvant chemotherapy may improve OS after curative hepatectomy for CRC liver metastases, though it did not significantly impact RFS. Larger-scale multicenter prospective studies with stratified analyses are needed to confirm these findings.

Background: The short-term outcomes of chemoradiotherapy (CRT) with S-1 (a combination of tegafur, gimeracil, and oteracil) following limited surgery for patients with T1 or T2 lower rectal cancer have shown encouraging results. Objectives: This study was designed to delve deeper into the long-term outcomes of CRT with S-1 after limited surgery, with the goal of evaluating both the long-term efficacy and potential risks associated with this treatment approach in patients diagnosed with T1 or T2 lower rectal cancer. Methods: This was conducted as a multicenter, single-arm, prospective phase II trial. The patient population consisted of individuals clinically diagnosed with either T1 or T2 lower rectal or anal canal cancer, with a maximum tumor diameter of 30 mm and classified as N0 or M0. Patients underwent local excision or endoscopic resection. After surgery, CRT with S-1 was administered to patients meeting several criteria, including the confirmation of well-differentiated or moderately differentiated adenocarcinoma, negative surgical margins, submucosal invasion depth of ≥1000 µm, and high tumor-budding grade (2/3). The primary endpoint of this study was relapse-free survival, while secondary endpoints included local recurrence-free survival, overall survival, anal sphincter preservation rate, and safety. Results: A total of 52 patients were included, with pathological diagnoses revealing T1 in 36 patients and T2 in 16 patients. The 3-year and 5-year relapse-free survival rates were 90.17% and 85.87%, respectively. The 3-year and 5-year local recurrence-free survival rates were 90.17% and 88.07%, respectively, while the 3-year and 5-year overall survival rates were 94.03% and 91.94%, respectively. Conclusions: CRT with S-1 after limited surgery for T1 lower rectal cancer demonstrated favorable outcomes in terms of recurrence, survival, and local control rates while effectively maintaining anal function in patients. However, further treatment approaches may be necessary to improve outcomes for patients diagnosed with stage T2 lower rectal cancer

Background: APC and MUTYH are both well-known colorectal polyposis causative genes. However, 30–50% of colorectal adenomatous polyposis cases are classified as colonic adenomatous polyposis of unknown etiology and lack identifiable pathogenic variants. Although guidelines recommend total proctocolectomy for colonic adenomatous polyposis of unknown etiology with over 100 adenomas, evidence is lacking. This study presents a unique case of localized colonic adenomatous polyposis of unknown etiology with multiple adenocarcinomas, treated with hemicolectomy and regional lymph node dissection. Case presentation: The patient was a 72-year-old woman whose colonoscopy revealed numerous polyps and two adenocarcinomas localized in the right side of the colon, with no lesions in the left side. The patient had no family history of polyposis or colorectal cancer. No extracolonic lesions, enlarged lymph nodes, or distant metastases were found. Considering the patient’s age and lesion localization, laparoscopic right hemicolectomy with regional lymph node dissection was performed. Histopathological diagnosis revealed three adenocarcinoma lesions with no lymph node metastasis. The most advanced pathological stage was T2N0M0 Stage I (UICC 8th edition). The patient was alive 5 years postoperatively, without recurrence of cancer or polyposis in the remaining colon and rectum. To diagnose hereditary colorectal cancer/polyposis, a germline multigene panel testing for APC, EPCAM, MBD4, MLH1, MLH3, MSH2, MSH3, MSH6, MUTYH, NTHL1, PMS2, POLD1, POLE, and TP53 was performed using DNA extracted from blood samples: however, no pathogenic variant was detected. Therefore, the patient was diagnosed with colonic adenomatous polyposis of unknown etiology. Conclusions: In this rare case, colonic adenomatous polyposis of unknown etiology, with numerous adenomatous polyps and multiple adenocarcinomas localized in the right side of the colon, was successfully treated with right hemicolectomy and regional lymph node dissection. Despite genetic analysis, no causative germline variants were identified. Segmental colectomy according to the distribution of polyps might be a curative approach.