Aberrant Glycosylation in Pancreatic Ductal Adenocarcinoma 3D Organoids Is Mediated by KRAS Mutations.

Aberrant glycosylation in tumor cells is a hallmark during carcinogenesis. KRAS gene mutations are the most well-known oncogenic abnormalities but their association with glycan alterations in pancreatic ductal adenocarcinoma (PDAC) is largely unknown. We employed patient-derived 3D organoids to culture pure live PDAC cells, excluding contamination by fibroblasts and immune cells, to gasp the comprehensive cancer cell surface glycan expression profile using lectin microarray and transcriptomic analyses. Surgical specimens from 24 PDAC patients were digested and embedded into a 3D culture system. Surface-bound glycans of 3D organoids were analyzed by high-density, 96-lectin microarrays. KRAS mutation status and expression of various glycosyltransferases were analyzed by RNA-seq. We successfully established 16 3D organoids: 14 PDAC, 1 intraductal papillary mucinous neoplasm (IPMN), and 1 normal pancreatic duct. KRAS was mutated in 13 (7 G12V, 5 G12D, 1 Q61L) and wild in 3 organoids (1 normal duct, 1 IPMN, 1 PDAC). Lectin reactivity of AAL (Aleuria aurantia) and AOL (Aspergillus oryzae) with binding activity to α1-3 fucose was higher in organoids with KRAS mutants than those with KRAS wild-type. FUT6 (α1-3fucosyltransferase 6) and FUT3 (α1-3/4 fucosyltransferase 3) expression was also higher in KRAS mutants than wild-type. Meanwhile, mannose-binding lectin (rRSL [Ralstonia solanacearum] and rBC2LA [Burkholderia cenocepacia]) signals were higher while those of galactose-binding lectins (rGal3C and rCGL2) were lower in the KRAS mutants. We demonstrated here that PDAC 3D-cultured organoids with KRAS mutations were dominantly covered in increased fucosylated glycans, pointing towards novel treatment targets and/or tumor markers.

Lectin-based phototherapy targeting cell surface glycans for pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is resistant to current treatments but lectin-based therapy targeting cell surface glycans could be a promising new horizon. Here, we report a novel lectin-based phototherapy (Lec-PT) that combines the PDAC targeting ability of rBC2LCN lectin to a photoabsorber, IRDye700DX (rBC2-IR700), resulting in a novel and highly specific near-infrared, light-activated, anti-PDAC therapy. Lec-PT cytotoxicity was first verified in vitro with a human PDAC cell line, Capan-1, indicating that rBC2-IR700 is only cytotoxic upon cellular binding and exposure to near-infrared light. The therapeutic efficacy of Lec-PT was subsequently verified in vivo using cell lines and patient-derived, subcutaneous xenografting into nude mice. Significant accumulation of rBC2-IR700 occurs as early as 2 hours postintravenous administration while cytotoxicity is only achieved upon exposure to near-infrared light. Repeated treatments further slowed tumor growth. Lec-PT was also assessed for off-target toxicity in the orthotopic xenograft model. Shielding of intraperitoneal organs from near-infrared light minimized off-target toxicity. Using readily available components, Lec-PT specifically targeted pancreatic cancer with high reproducibility and on-target, inducible toxicity. Rapid clinical development of this method is promising as a new modality for treatment of pancreatic cancer.

Survival impact on triple-modal strategy comprising hyperthermia, external radiation, and chemotherapy for unresectable locally advanced (UR-LA) pancreatic ductal adenocarcinoma.

BACKGROUND: Present treatment strategy for unresectable locally advanced (UR-LA) pancreatic ductal adenocarcinoma (PDAC) patients is controversial. Hence, a triple-modal therapy, which is a multidisciplinary strategy, was designed for patients with UR-LA PDAC by adding hyperthermia to conventional chemoradiotherapy at our institution. In this study we aimed to evaluate the effectiveness of this strategy. METHODS: Data of 21 UR-LA PDAC patients who underwent the triple-modal treatment were retrospectively analyzed for evaluating the safety and oncological effect of the treatment. The treatment schedule included, five concurrent infusions of gemcitabine (800 mg/m2) followed by hyperthermia (1 h) and X-ray (2 Gy) or proton beam radiation (2.7 Gy) on days 1, 8, 15, 29, and 36. Additional radiotherapies applied a total dose of 50 Gy/25 fr for X-ray radiation or 67.5 Gy/25 fr for proton beam radiation. RESULTS: Median overall survival (OS) was 23.6 months. Conversion surgery was performed in 5 patients (23.8%), and a R0 margin could be achieved in 4 of them; however, their median OS (16.3 months) tended to be shorter than that of the patients who did not undergo resection (23.6 months, p = 0.562). Further, the median OS of patients who underwent proton beam radiation (28.0 months) was significantly longer than that of patients who underwent X-ray radiation (13.9 months, p = 0.045). Most adverse events were manageable, except for one grade 3 gastric ulcer. The median tumor size and marker reduction rates were -17% and -91%, respectively. The tumor responses were partial response, stable disease, and progressive disease in 3, 15, and 3 patients, respectively. CONCLUSION: Triple-modal strategy, especially when combined with proton beam radiation, is feasible and results in favorable survival outcomes in patients with UR-LA PDAC.

Exploring optimal examination to detect occult anastomotic leakage after rectal resection in patients with diverting stoma.

BACKGROUND: When considering "early stoma closure", both standardized inclusion/exclusion criteria and standardized methods to assess anastomosis are necessary to reduce the risk of occult anastomotic leakage (AL). However, in the immediate postoperative period, neither have the incidence and risk factors of occult AL in patients with diverting stoma (DS) been clarified nor have methods to assess anastomosis been standardized. The aim of this study was to elucidate the incidence and risk factors of occult AL in patients who had undergone rectal resection with DS and to evaluate the significance of computed tomography (CT) following water-soluble contrast enema (CE) to detect occult anastomotic leakage. METHODS: This was a single institutional prospective observational study of patients who had undergone rectal resection with the selective use of DS between May and October 2019. Fifteen patients had undergone CE and CT to assess for AL on postoperative day (POD) 7, and CT was performed just after CE. Univariate analysis was performed to assess the relationship between preoperative variables and the incidence of occult AL on POD 7. RESULTS: The incidence of occult AL on postoperative day 7 was 6 of 15 (40%). Hand-sewn anastomosis, compared with stapled anastomosis, was a significant risk factor. Five more cases with occult AL that could not be detected with CE could be detected on CT following CE; CE alone had a 33% false-negative radiological result rate. CONCLUSIONS: Hand-sewn anastomosis appeared to be a risk factor for occult AL, and CE alone had a high false-negative radiological result rate. When considering the introduction of early stoma closure, stapled anastomosis and CT following CE could be an appropriate inclusion criterion and preoperative examination, respectively.

Cetuximab delivery and antitumor effects are enhanced by mild hyperthermia in a xenograft mouse model of pancreatic cancer.

Even with current promising antitumor antibodies, their antitumor effects on stroma-rich solid cancers have been insufficient. We used mild hyperthermia with the intent of improving drug delivery by breaking the stromal barrier. Here, we provide preclinical evidence of cetuximab + mild hyperthermia therapy. We used four in vivo pancreatic cancer xenograft mouse models with different stroma amounts (scarce, MIAPaCa-2; moderate, BxPC-3; and abundant, Capan-1 and Ope-xeno). Cetuximab (1 mg/kg) was given systemically, and the mouse leg tumors were concurrently heated using a water bath method for 30 min at three different temperatures, 25°C (control), 37°C (intra-abdominal organ level), or 41°C (mild hyperthermia) (n = 4, each group). The evaluated variables were the antitumor effects, represented by tumor volume, and in vivo cetuximab accumulation, indirectly quantified by the immunohistochemical fluorescence intensity value/cell using antibodies against human IgG Fc. At 25°C, the antitumor effects were sufficient, with a cetuximab accumulation value (florescence intensity/cell) of 1632, in the MIAPaCa-2 model, moderate (1063) in the BxPC-3 model, and negative in the Capan-1 and Ope-xeno models (760, 461). By applying 37°C or 41°C heat, antitumor effects were enhanced shown in decreased tumor volumes. These enhanced effects were accompanied by boosted cetuximab accumulation, which increased by 2.8-fold (2980, 3015) in the BxPC-3 model, 2.5- or 4.8-fold (1881, 3615) in the Capan-1 model, and 3.2- or 4.2-fold (1469, 1922) in the Ope-xeno model, respectively. Cetuximab was effective in treating even stroma-rich and k-ras mutant pancreatic cancer mouse models when the drug delivery was improved by combination with mild hyperthermia.