Targeting cancer-associated fibroblast autophagy renders pancreatic cancer eradicable with immunochemotherapy by inhibiting adaptive immune resistance.

Accumulating evidence suggests that cancer-associated fibroblast (CAF) macroautophagy/autophagy is crucial in tumor development and may be a therapeutic target for pancreatic ductal adenocarcinoma (PDAC). However, the role of CAF autophagy during immune surveillance and cancer immunotherapy is unclear. The present study revealed that the inhibition of CAF autophagy suppresses in vivo tumor development in immune-deficient xenografts. This deletion compromises anti-tumor immunity and anti-tumor efficacy both in vitro and in vivo by upregulating CD274/PDL1 levels in an immune-competent mouse model. A block in CAF autophagy reduced the production of IL6 (interleukin 6), disrupting high desmoplastic TME and decreasing USP14 expression at the transcription level in pancreatic cancer cells. We further identify USP14 as the post-translational factor responsible for downregulating CD274 expression by removing K63 linked-ubiquitination at the K280 residue. Finally, chloroquine diphosphate-loaded mesenchymal stem cell (MSC)-liposomes, by accurately targeting CAFs, inhibited CAF autophagy, improving the efficacy of immunochemotherapy to combat pancreatic cancer.Abbreviation: AIR: adaptive immune resistance; ATRA: all-trans-retinoicacid; CAF: cancer-associated fibroblast; CD274/PDL1: CD274 molecule; CM: conditioned medium; CQ: chloroquine diphosphate; CyTOF: Mass cytometry; FGF2/bFGF: fibroblast growth factor 2; ICB: immune checkpoint blockade; IF: immunofluorescence; IHC: immunohistochemistry; IP: immunoprecipitation; MS: mass spectrometer; MSC: mesenchymal stem cell; PDAC: pancreatic ductal adenocarcinoma; TEM: transmission electron microscopy; TILs: tumor infiltrating lymphocytes; TME: tumor microenvironment; USP14: ubiquitin specific peptidase 14.

Targeting MFAP5 in cancer-associated fibroblasts sensitizes pancreatic cancer to PD-L1-based immunochemotherapy via remodeling the matrix.

Highly desmoplastic and immunosuppressive tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) contributes to tumor progression and resistance to current therapies. Clues targeting the notorious stromal environment have offered hope for improving therapeutic response whereas the underlying mechanism remains unclear. Here, we find that prognostic microfibril associated protein 5 (MFAP5) is involved in activation of cancer-associated fibroblasts (CAFs). Inhibition of MFAP5highCAFs shows synergistic effect with gemcitabine-based chemotherapy and PD-L1-based immunotherapy. Mechanistically, MFAP5 deficiency in CAFs downregulates HAS2 and CXCL10 via MFAP5/RCN2/ERK/STAT1 axis, leading to angiogenesis, hyaluronic acid (HA) and collagens deposition reduction, cytotoxic T cells infiltration, and tumor cells apoptosis. Additionally, in vivo blockade of CXCL10 with AMG487 could partially reverse the pro-tumor effect from MFAP5 overexpression in CAFs and synergize with anti-PD-L1 antibody to enhance the immunotherapeutic effect. Therefore, targeting MFAP5highCAFs might be a potential adjuvant therapy to enhance the immunochemotherapy effect in PDAC via remodeling the desmoplastic and immunosuppressive microenvironment.

Targeting ubiquitin-specific protease 8 sensitizes anti-programmed death-ligand 1 immunotherapy of pancreatic cancer.

Programmed death-1 (PD-1) and its ligand programmed death-ligand 1 (PD-L1) help tumor cells evade immune surveillance, and are regarded as important targets of anti-tumor immunotherapy. Post-translational modification of PD-L1 has potential value in immunosuppression. Here, we identified that ubiquitin-specific protease 8 (USP8) deubiquitinates PD-L1. Pancreatic cancer tissues exhibited significantly increased USP8 levels compared with those in normal tissues. Clinically, the expression of USP8 showed a significant association with the tumor-node-metastasis stage in multiple patient-derived cohorts of pancreatic cancer. Meanwhile, USP8 deficiency could reduce tumor invasion and migration and tumor size in an immunity-dependent manner, and improve anti-tumor immunogenicity. USP8 inhibitor pretreatment led to reduced tumorigenesis and immunocompetent mice with Usp8 knockdown tumors exhibited extended survival. Moreover, USP8 interacted positively with PD-L1 and upregulated its expression by inhibiting the ubiquitination-regulated proteasome degradation pathway in pancreatic cancer. Combination therapy with a USP8 inhibitor and anti-PD-L1 effectively suppressed pancreatic tumor growth by activation of cytotoxic T-cells and the anti-tumor immunity was mainly dependent on the PD-L1 pathway and CD8 + T cells. Our findings highlight the importance of targeting USP8, which can sensitize PD-L1-targeted pancreatic cancer to immunotherapy and might represent a novel therapeutic strategy to treat patients with pancreatic tumors in the future.

Olfactory sensory experience regulates gliomagenesis via neuronal IGF1.

Animals constantly receive various sensory stimuli, such as odours, sounds, light and touch, from the surrounding environment. These sensory inputs are essential for animals to search for food and avoid predators, but they also affect their physiological status, and may cause diseases such as cancer. Malignant gliomas-the most lethal form of brain tumour1-are known to intimately communicate with neurons at the cellular level2,3. However, it remains unclear whether external sensory stimuli can directly affect the development of malignant glioma under normal living conditions. Here we show that olfaction can directly regulate gliomagenesis. In an autochthonous mouse model that recapitulates adult gliomagenesis4-6 originating in oligodendrocyte precursor cells (OPCs), gliomas preferentially emerge in the olfactory bulb-the first relay of brain olfactory circuitry. Manipulating the activity of olfactory receptor neurons (ORNs) affects the development of glioma. Mechanistically, olfaction excites mitral and tufted (M/T) cells, which receive sensory information from ORNs and release insulin-like growth factor 1 (IGF1) in an activity-dependent manner. Specific knockout of Igf1 in M/T cells suppresses gliomagenesis. In addition, knocking out the IGF1 receptor in pre-cancerous mutant OPCs abolishes the ORN-activity-dependent mitogenic effects. Our findings establish a link between sensory experience and gliomagenesis through their corresponding sensory neuronal circuits.

Human endogenous retrovirus-H long terminal repeat-associating 2: The next immune checkpoint for antitumour therapy.

Human endogenous retrovirus-H long terminal repeat-associating 2 (HHLA2) is a newly emerging immune checkpoint that belongs to B7 family. HHLA2 has a co-stimulatory receptor transmembrane and immunoglobulin domain containing 2 (TMIGD2) and a newly discovered co-inhibitory receptor killer cell Ig-like receptor, three Ig domains, and long cytoplasmic tail (KIR3DL3), which endows it with both immunostimulant and immunosuppression functions in cancer development. In this review, we summarize the HHLA2 expression profile in human cancers, its association with cancer prognosis and clinical features, and its dual roles in regulating cancer immune response through up-to-date literatures. Furthermore, we highlight that precision cancer immunotherapy through manipulating HHLA2-KIR3DL3/TMIGD2 interaction is a promising antitumour strategy.

Combination cancer immunotherapy targeting TNFR2 and PD-1/PD-L1 signaling reduces immunosuppressive effects in the microenvironment of pancreatic tumors.

BACKGROUNDS: In advanced pancreatic ductal adenocarcinoma (PDAC), immune therapy, including immune checkpoint inhibitors, has limited efficacy, encouraging the study of combination therapy. METHODS: Tumor necrosis factor receptor 2 (TNFR2) was analyzed via immunohistochemistry, immunofluorescence, western blotting, and ELISAs. The in vitro mechanism that TNFR2 regulates programmed cell death 1 ligand 1 (PD-L1) was investigated using immunofluorescence, immunohistochemistry, flow cytometry, western blotting, and chromatin immunoprecipitation (ChIP). In vivo efficacy and mechanistic studies, using C57BL/6 mice and nude mice with KPC cell-derived subcutaneous and orthotopic tumors, employed antibodies against TNFR2 and PD-L1. Survival curves were constructed for the orthotopic model and a genetically engineered PDAC model (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre). Mass cytometry, immunohistochemistry, and flow cytometry analyzed local and systemic alterations in the immunophenotype. RESULTS: TNFR2 showed high expression and is a prognostic factor in CD8+ T cell-enriched pancreatic cancer. TNFR2 promotes tumorigenesis and progression of pancreatic cancer via dual effect: suppressing cancer immunogenicity and partially accelerating tumor growth. TNFR2 positivity correlated with PD-L1, and in vitro and in vivo, it could regulate the expression of PDL1 at the transcription level via the p65 NF-κB pathway. Combining anti-TNFR2 and PD-L1 antibodies eradicated tumors, prolonged overall survival in pancreatic cancer, and induced strong antitumor immune memory and secondary prevention by reducing the infiltration of Tregs and tumor-associated macrophages and inducing CD8+ T cell activation in the PDAC microenvironment. Finally, the antitumor immune response derived from combination therapy is mainly dependent on CD8+ T cells, partially dependent on CD4+ T cells, and independent of natural killer cells. CONCLUSIONS: Anti-TNFR2 and anti-PD-L1 combination therapy eradicated tumors by inhibiting their growth, relieving tumor immunosuppression, and generating robust memory recall.

Non-cytomembrane PD-L1: An atypical target for cancer.

Programmed death ligand 1 (PD-L1) has conventionally been considered as a type I transmembrane protein that can interact with its receptor, programmed cell death 1 (PD-1), thus inducing T cell deactivation and immune escape. However, targeting the PD-1/PD-L1 axis has achieved adequate clinical responses in very few specific malignancies. Recent studies have explored the extracellularly and subcellularly located PD-L1, namely, nuclear PD-L1 (nPD-L1), cytoplasmic PD-L1 (cPD-L1), soluble PD-L1 (sPD-L1), and extracellular vesicle PD-L1 (EV PD-L1), which might shed light on the resistance to anti-PD1/PDL1 therapy. In this review, we summarize the four atypical localizations of PD-L1 with a focus on their novel functions, such as gene transcription regulation, therapeutic efficacy prediction, and resistance to various cancer therapies. Additionally, we highlight that non-cytomembrane PD-L1s are of significant cancer diagnostic value and are promising therapeutic targets to treat cancer.

Regulator of calcineurin 1 gene isoform 4 in pancreatic ductal adenocarcinoma regulates the progression of tumor cells.

Therapeutic strategies to treat pancreatic ductal adenocarcinoma (PDAC) remain unsatisfying and limited. Therefore, it is imperative to fully determine the mechanisms underlying PDAC progression. In the present study, we report a novel role of regulator of calcineurin 1, isoform 4 (RCAN1.4) in regulating PDAC progression. We demonstrated that RCAN1.4 expression was decreased significantly in PDAC tissues compared with that in para-cancerous tissues, and correlated with poor prognosis of patients with pancreatic cancer. In vitro, stable high expression of RCAN1.4 could suppress the metastasis and proliferation and angiogenesis of pancreatic tumor cells. In addition, interferon alpha inducible protein 27 (IFI27) was identified as having a functional role in RCAN1.4-mediated PDAC migration and invasion, while VEGFA play a vital role in RCAN1.4-mediated PDAC angiogenesis. Analysis of mice with subcutaneously/orthotopic implanted xenograft tumors and liver metastasis model confirmed that RCAN1.4 could modulate the growth, metastasis, and angiogenesis of tumors via IFI27/VEGFA in vivo. In conclusion, our results suggested that RCAN1.4 suppresses the growth, metastasis, and angiogenesis of PDAC, functioning partly via IFI27 and VEGFA. Importantly, our results provided possible diagnostic criteria and therapeutic targets for PDAC.

[Expression of cyclooxygenase-2 mRNA and identification of its spliceriant in human myometrium obtained from women in labor].

OBJECTIVE: To investigate the expression of cyclooxygenase-2 (COX-2) in human lower segments of myometrium obtained from women in labor and those not in labor and identify the splice variant of COX-2. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used for investigating the expression of COX-2. According to the sequence of rat COX-2 splice variant, the primers were designed and synthesized, then the splice variant of COX-2 in human myometrium from woman in labor was identified, cloned into vector and sequenced. RESULTS: The results showed that (1) The Expression of COX-2 mRNA was lower in human myometrium obtained from women who were not in labor than those in labor. (2) A new band of COX-2 was obtained in myometrium from a woman in labor. The fragment includes an unspliced intron, which locates between exons 7 and 8. CONCLUSION: COX-2 gene is not only expressed highly in human myometrium from women in labor, but also produced splicing variant by alternative splicing.