Ultra-sensitive CTC-based liquid biopsy for pancreatic cancer enabled by large blood volume analysis.

The limited sensitivity of circulating tumor cell (CTC) detection in pancreatic adenocarcinoma (PDAC) stems from their extremely low concentration in the whole circulating blood, necessitating enhanced detection methodologies. This study sought to amplify assay-sensitivity by employing diagnostic leukapheresis (DLA) to screen large blood volumes. Sixty patients were subjected to DLA, with a median processed blood volume of ~ 2.8 L and approximately 5% of the resulting DLA-product analyzed using CellSearch (CS). Notably, DLA significantly increased CS-CTC detection to 44% in M0-patients and 74% in M1-patients, yielding a 60-fold increase in CS-CTC enumeration. DLA also provided sufficient CS-CTCs for genomic profiling, thereby delivering additional genomic information compared to tissue biopsy samples. DLA CS-CTCs exhibited a pronounced negative prognostic impact on overall survival (OS), evidenced by a reduction in OS from 28.6 to 8.5 months (univariate: p = 0.002; multivariable: p = 0.043). Additionally, a marked enhancement in sensitivity was achieved (by around 3-4-times) compared to peripheral blood (PB) samples, with positive predictive values for OS being preserved at around 90%. Prognostic relevance of CS-CTCs in PDAC was further validated in PB-samples from 228 PDAC patients, consolidating the established association between CTC-presence and reduced OS (8.5 vs. 19.0 months, p < 0.001). In conclusion, DLA-derived CS-CTCs may serve as a viable tool for identifying high-risk PDAC-patients and aiding the optimization of multimodal treatment strategies. Moreover, DLA enables comprehensive diagnostic profiling by providing ample CTC material, reinforcing its utility as a reliable liquid-biopsy approach. This high-volume liquid-biopsy strategy presents a potential pathway for enhancing clinical management in this malignancy.

BRAFV600E mutation: A promising target in colorectal neuroendocrine carcinoma.

To determine the role of BRAFV600E mutation and MAPK signaling as well as the effects of BRAF and MEK directed therapy in gastroenteropancreatic neuroendocrine neoplasia (GEP-NEN), with a focus on highly aggressive gastroenteropancreatic neuroendocrine carcinoma (GEP-NEC). Using Sanger sequencing of BRAF exon 15 we determined the frequency of BRAFV600E mutations in 71 primary GEP-NENs. MEK phosphorylation was examined by immunohistochemistry in corresponding tissue samples. To evaluate the biological relevance of BRAFV600E mutation and MAPK signaling in GEP-NECs, effects of a pharmacological BRAF and MEK inhibition were analyzed in NEC cell lines both in vitro and in vivo. BRAFV600E mutation was detected in 9.9% of all GEP-NENs. Interestingly, only NECs of the colon harbored BRAFV600E mutations, leading to a mutation frequency of 46.7% in this subgroup of patients. In addition, a BRAFV600E mutation was significantly associated with high levels of MEK phosphorylation (pMEK) and advanced tumor stages. Pharmacological inhibition of BRAF and MEK abrogated NEC cell growth, inducing G1 cell cycle arrest and apoptosis only in BRAFV600E mutated cells. BRAF inhibitor dabrafenib and MEK inhibitor trametinib prevented growth of BRAFV600E positive NEC xenografts. High frequencies of BRAFV600E mutation and elevated expression levels of pMEK were detected in biologically aggressive and highly proliferative colorectal NECs. We provide evidence that targeting BRAF oncogene may represent a therapeutic strategy for patients with BRAF mutant colorectal NECs.

Adhesion protein VSIG1 is required for the proper differentiation of glandular gastric epithelia.

VSIG1, a cell adhesion protein of the immunoglobulin superfamily, is preferentially expressed in stomach, testis, and certain gastric, esophageal and ovarian cancers. Here, we describe the expression patterns of three alternatively spliced isoforms of mouse Vsig1 during pre- and postnatal development of stomach and potential function of Vsig1 in differentiation of gastric epithelia. We show that isoforms Vsig1A and Vsig1B, which differ in the 3'untranslated region, are expressed in the early stages of stomach development. Immunohistochemical analysis revealed that VSIG1 is restricted to the adherens junction of the glandular epithelium. The shorter transcript Vsig1C is restricted to the testis, encodes an N-terminal truncated protein and is presumably regulated by an internal promoter, which is located upstream of exon 1b. To determine whether the 5' flanking region of exon 1a specifically targets the expression of Vsig1 to stomach epithelia, we generated and analyzed transgenic mice. The 4.8-kb fragment located upstream of exon 1a was sufficient to direct the expression of the reporter gene to the glandular epithelia of transgenic stomach. To determine the role of VSIG1 during the development of stomach epithelia, an X-linked Vsig1 was inactivated in embryonic stem cells (ESCs). Although Vsig1(-/Y) ESCs were only able to generate low coat color chimeric mice, no male chimeras transmitted the targeted allele to their progeny suggesting that the high contribution of Vsig1(-/Y) cells leads to the lethality of chimeric embryos. Analysis of chimeric stomachs revealed the differentiation of VSIG1-null cells into squamous epithelia inside the glandular region. These results suggest that VSIG1 is required for the establishment of glandular versus squamous epithelia in the stomach.

Sox15 is required for skeletal muscle regeneration.

The Sox genes define a family of transcription factors that play a key role in the determination of cell fate during development. The preferential expression of the Sox15 in the myogenic precursor cells led us to suggest that the Sox15 is involved in the specification of myogenic cell lineages or in the regulation of the fusion of myoblasts to form myotubes during the development and regeneration of skeletal muscle. To identify the physiological function of Sox15 in mice, we disrupted the Sox15 by homologous recombination in mice. Sox15-deficient mice were born at expected ratios, were healthy and fertile, and displayed normal long-term survival rates. Histological analysis revealed the normal ultrastructure of myofibers and the presence of comparable amounts of satellite cells in the skeletal muscles of Sox15(-/-) animals compared to wild-type animals. These results exclude the role of Sox15 in the development of satellite cells. However, cultured Sox15(-/-) myoblasts displayed a marked delay in differentiation potential in vitro. Moreover, skeletal muscle regeneration in Sox15(-/-) mice was attenuated after application of a crush injury. These results suggest a requirement for Sox15 in the myogenic program. Expression analyses of the early myogenic regulated factors MyoD and Myf5 showed the downregulation of the MyoD and upregulation of the Myf5 in Sox15(-/-) myoblasts. These results show an increased proportion of the Myf5-positive cells and suggest a role for Sox15 in determining the early myogenic cell lineages during skeletal muscle development.