Quantitative Live Imaging Reveals Phase Dependency of PDAC Patient-Derived Organoids on ERK and AMPK Activity.

Patient-derived organoids represent a novel platform to recapitulate the cancer cells in the patient tissue. While cancer heterogeneity has been extensively studied by a number of omics approaches, little is known about the spatiotemporal kinase activity dynamics. Here we applied a live imaging approach to organoids derived from 10 pancreatic ductal adenocarcinoma (PDAC) patients to comprehensively understand their heterogeneous growth potential and drug responses.

Wnt-deficient and hypoxic environment orchestrates squamous reprogramming of human pancreatic ductal adenocarcinoma.

Human pancreatic cancer is characterized by the molecular diversity encompassing native duct-like and squamous cell-like identities, but mechanisms underlying squamous transdifferentiation have remained elusive. To comprehensively capture the molecular diversity of human pancreatic cancer, we here profiled 65 patient-derived pancreatic cancer organoid lines, including six adenosquamous carcinoma lines. H3K27me3-mediated erasure of the ductal lineage specifiers and hijacking of the TP63-driven squamous-cell programme drove squamous-cell commitment, providing survival benefit in a Wnt-deficient environment and hypoxic conditions.

Delivery of a BET protein degrader via a CEACAM6-targeted antibody-drug conjugate inhibits tumour growth in pancreatic cancer models.

Pancreatic ductal adenocarcinoma (PDAC) has the worst prognosis of all cancers. To improve PDAC therapy, we establish screening systems based on organoid and co-culture technologies and find a payload of antibody-drug conjugate (ADC), a bromodomain and extra-terminal (BET) protein degrader named EBET. We select CEACAM6/CD66c as an ADC target and developed an antibody, #84.

Blockage of retinoic acid signaling via RARγ suppressed the proliferation of pancreatic cancer cells by arresting the cell cycle progression of the G1-S phase.

Background: Our study and several studies have reported that in some cancers, including pancreatic ductal adenocarcinoma (PDAC), the expression of squamous lineage markers, such as esophagus-tissue-specific genes, correlated with a poor prognosis. However, the mechanism by which the acquisition of squamous lineage phenotypes leads to a poor prognosis remains unclear. We previously reported that retinoic acid signaling via retinoic acid receptor γ (RARγ signaling) determines the differentiation lineage into the esophageal squamous epithelium.

Cell-matrix interface regulates dormancy in human colon cancer stem cells.

Cancer relapse after chemotherapy remains a main cause of cancer-related death. Although the relapse is thought to result from the propagation of resident cancer stem cells, a lack of experimental platforms that enable the prospective analysis of cancer stem cell dynamics with sufficient spatiotemporal resolution has hindered the testing of this hypothesis. Here we develop a live genetic lineage-tracing system that allows the longitudinal tracking of individual cells in xenotransplanted human colorectal cancer organoids, and identify LGR5 cancer stem cells that exhibit a dormant behaviour in a chemo-naive state.

Xenografts Derived From Patients' Ascites Recapitulate the Gemcitabine Resistance Observed in Pancreatic Cancer Patients.

Objectives: Most patient-derived pancreatic ductal adenocarcinoma (PDAC) xenografts have been established from surgical specimens of patients who have not received chemotherapy. However, xenografts have rarely been established from chemotherapy-resistant, advanced PDACs, because such cases are usually inoperable. The purpose of this study is to establish patient-derived xenografts using PDAC cells refractory to chemotherapy.

Splicing of Friend Murine Leukemia Virus env-mRNA Enhances Its Ability to Form Polysomes.

Friend murine leukemia virus (MLV) belongs to the gamma retroviruses of the Retroviridae family. The positive-sense RNA of its genome contains a 5' long terminal repeat (LTR), 5' leader sequence, gag, pol, env, and 3' LTR. Transcription from proviral DNA begins from the R region of the 5' LTR and ends at the polyadenylation signal located at the R region of the other end of the 3' LTR.

Polyadenylation of Friend murine leukemia virus env-mRNA is affected by its splicing.

As splicing was previously found to be important for increasing Friend murine leukemia virus env-mRNA stability and translation, we investigated whether splicing of env-mRNA affected the poly(A) tail length using env expression vectors that yielded unspliced or spliced env-mRNA. Incomplete polyadenylation was detected in a fraction of the unspliced env-mRNA products in an env gene-dependent manner, showing that splicing of Friend murine leukemia virus plays an important role in the efficiency of complete polyadenylation of env-mRNA. These results suggested that the promotion of complete polyadenylation of env-mRNA by splicing might partially explain up-regulation of Env protein expression as a result of splicing.

A 38 nt region and its flanking sequences within gag of Friend murine leukemia virus are crucial for splicing at the correct 5' and 3' splice sites.

The genome of the Friend murine leukemia virus (Fr-MLV) contains a 5' splice site (5'ss) located at 205 nt and a 3'ss located at 5489 nt. In our previous studies, it was shown that if the HindIII-BglII (879-1904 bp) fragment within gag is deleted from the proA8m1 vector, which carries the entire Fr-MLV sequence, then cryptic splicing of env-mRNA occurs. Here, attempts were made to identify the genomic segment(s) in this region that is/are essential to correct splicing.

The 0.3-kb fragment containing the R-U5-5'leader sequence of Friend murine leukemia virus influences the level of protein expression from spliced mRNA.

Background: A neuropathogenic variant of Friend murine leukemia virus (Fr-MLV) clone A8 induces spongiform neurodegeneration when infected into neonatal rats. Studies with chimeras constructed from the A8 virus and the non-neuropathogenic Fr-MLV clone 57 identified a 0.3-kb KpnI-AatII fragment containing a R-U5-5'leader sequence as an important determinant for inducing spongiosis, in addition to the env gene of A8 as the primary determinant.