Pancreatic ductal adenocarcinoma (PDA) exhibits one of the poorest prognosis of all solid tumours and poses an unsolved problem in cancer medicine. Despite the recent success of two combination ...chemotherapies for palliative patients, the modest survival benefits are often traded against significant side effects and a compromised quality of life. Although the molecular events underlying the initiation and progression of PDA have been intensively studied and are increasingly understood, the reasons for the poor therapeutic response are hardly apprehended. One leading hypothesis over the last few years has been that the pronounced tumour microenvironment in PDA not only promotes carcinogenesis and tumour progression but also mediates therapeutic resistance. To this end, targeting of various stromal components and pathways was considered a promising strategy to biochemically and biophysically enhance therapeutic response. However, none of the efforts have yet led to efficacious and approved therapies in patients. Additionally, recent data have shown that tumour-associated fibroblasts may restrain rather than promote tumour growth, reinforcing the need to critically revisit the complexity and complicity of the tumour-stroma with translational implications for future therapy and clinical trial design.
Pancreatic ductal adenocarcinoma (PDAC) belongs to the most lethal solid tumors in humans. A histological hallmark feature of PDAC is the pronounced tumor microenvironment (TME) that dynamically ...evolves during tumor progression. The TME consists of different non-neoplastic cells such as cancer-associated fibroblasts (CAFs), immune cells, endothelial cells and neurons. Furthermore, abundant extracellular matrix (ECM) components such as collagen and hyaluronic acid (HA) as well as matricellular proteins create a highly dynamic and hypovascular TME with multiple biochemical and physical interactions among the various cellular and acellular components that promote tumor progression and therapeutic resistance. In recent years, intensive research efforts have resulted in a significantly improved understanding of the biology and pathophysiology of the TME in PDAC, and novel stroma-targeted approaches are emerging that may help to improve the devastating prognosis of PDAC patients. However, none of anti-stromal therapies have been approved in patients so far, and there is still a large discrepancy between multiple successful preclinical results and subsequent failure in clinical trials. Furthermore, recent findings suggest that parts of the TME may also possess tumor-restraining properties rendering tailored therapies even more challenging.
Pancreatic cancer remains one of the most aggressive tumours with a 5-year survival rate of less than 5%. The dismal prognosis of this tumour entity that is associated with a high degree of drug ...resistance has not changed over the past decades. Since 1997, gemcitabine-based regimens have been the therapy of choice for advanced pancreatic cancer. Recently, however, new combination chemotherapy regimens achieved a significant survival benefit compared to gemcitabine-based therapies. In addition, novel approaches to improve drug delivery are currently being developed, and new drugs targeting signalling pathways both within the tumour cells and the tumour microenvironment are undergoing preclinical and clinical validation. Furthermore, efforts are being made to identify predictive markers for individualised treatment approaches based on molecular tumour characteristics. This review provides an overview on current and emerging concepts as well as novel targets for systemic treatment of advanced pancreatic cancer. Combination therapies incorporating drugs directed against these new targets may open new avenues for improving the efficacy of current treatment approaches and overcoming the devastating prognosis of pancreatic cancer patients.
Abstract
Emerging data demonstrate that the activity of immune cells can be modulated by microbial molecules. Here, we show that the short-chain fatty acids (SCFAs) pentanoate and butyrate enhance ...the anti-tumor activity of cytotoxic T lymphocytes (CTLs) and chimeric antigen receptor (CAR) T cells through metabolic and epigenetic reprograming. We show that in vitro treatment of CTLs and CAR T cells with pentanoate and butyrate increases the function of mTOR as a central cellular metabolic sensor, and inhibits class I histone deacetylase activity. This reprogramming results in elevated production of effector molecules such as CD25, IFN-γ and TNF-α, and significantly enhances the anti-tumor activity of antigen-specific CTLs and ROR1-targeting CAR T cells in syngeneic murine melanoma and pancreatic cancer models. Our data shed light onto microbial molecules that may be used for enhancing cellular anti-tumor immunity. Collectively, we identify pentanoate and butyrate as two SCFAs with therapeutic utility in the context of cellular cancer immunotherapy.
Tumour-associated macrophages play an important role in mediating tumour progression. In pancreatic cancer, infiltrating macrophages are known to mediate tumour progression and have been identified ...in invasive tumours and in early preinvasive pancreatic intraepithelial precursor lesions. We aimed to study the impact of pharmacological macrophage depletion by liposomal clodronate in a genetic mouse model of pancreatic cancer.
KPC mice (
) were treated for 12 weeks with liposomal clodronate or control liposomes. Tumour and metastasis formation as well as alterations in local and circulating immune cells and cytokines were analysed.
Treatment with liposomal clodronate effectively reduced CD11b-positive macrophages both in the pancreas and other organs such as liver, lung and spleen. While tumour incidence and growth were only slightly reduced, metastasis formation in the liver and lungs was significantly diminished after macrophage depletion. This antimetastatic effect was independent of the presence of an endogenous primary tumour, since reduced pulmonary colonisation was also detected in clodronate-pretreated mice after tail vein injection of syngeneic pancreatic cancer cell lines. Macrophage inhibition by liposomal clodronate was associated with significantly impaired angiogenesis, reduced circulating vascular endothelial growth factor levels and decreased circulating CD4+CD25+ T cells. These alterations could be confirmed in an independent macrophage depletion model using CD11b-diphtheria toxin receptor mice.
Pharmacological depletion of macrophages in a genetic mouse model of pancreatic cancer markedly reduced metastasis formation and is associated with impaired angiogenesis and reduced CD4+CD25+ T cell levels. Pharmacological targeting of infiltrating macrophages represents a promising novel tool for antimetastatic therapeutic approaches.
The Immune Microenvironment in Pancreatic Cancer Huber, Magdalena; Brehm, Corinna U; Gress, Thomas M ...
International journal of molecular sciences,
10/2020, Letnik:
21, Številka:
19
Journal Article
Recenzirano
Odprti dostop
The biology of solid tumors is strongly determined by the interactions of cancer cells with their surrounding microenvironment. In this regard, pancreatic cancer (pancreatic ductal adenocarcinoma, ...PDAC) represents a paradigmatic example for the multitude of possible tumor-stroma interactions. PDAC has proven particularly refractory to novel immunotherapies, which is a fact that is mediated by a unique assemblage of various immune cells creating a strongly immunosuppressive environment in which this cancer type thrives. In this review, we outline currently available knowledge on the cross-talk between tumor cells and the cellular immune microenvironment, highlighting the physiological and pathological cellular interactions, as well as the resulting therapeutic approaches derived thereof. Hopefully a better understanding of the complex tumor-stroma interactions will one day lead to a significant advancement in patient care.
The International Cancer of the Pancreas Screening Consortium met in 2018 to update its consensus recommendations for the management of individuals with increased risk of pancreatic cancer based on ...family history or germline mutation status (high-risk individuals).
A modified Delphi approach was employed to reach consensus among a multidisciplinary group of experts who voted on consensus statements. Consensus was considered reached if ≥75% agreed or disagreed.
Consensus was reached on 55 statements. The main goals of surveillance (to identify high-grade dysplastic precursor lesions and T1N0M0 pancreatic cancer) remained unchanged. Experts agreed that for those with familial risk, surveillance should start no earlier than age 50 or 10 years earlier than the youngest relative with pancreatic cancer, but were split on whether to start at age 50 or 55. Germline
mutation carriers with one affected first-degree relative are now considered eligible for surveillance. Experts agreed that preferred surveillance tests are endoscopic ultrasound and MRI/magnetic retrograde cholangiopancreatography, but no consensus was reached on how to alternate these modalities. Annual surveillance is recommended in the absence of concerning lesions. Main areas of disagreement included if and how surveillance should be performed for hereditary pancreatitis, and the management of indeterminate lesions.
Pancreatic surveillance is recommended for selected high-risk individuals to detect early pancreatic cancer and its high-grade precursors, but should be performed in a research setting by multidisciplinary teams in centres with appropriate expertise. Until more evidence supporting these recommendations is available, the benefits, risks and costs of surveillance of pancreatic surveillance need additional evaluation.
TGF-β/Activin induces epithelial-to-mesenchymal transition and stemness in pancreatic ductal adenocarcinoma (PDAC). However, the microRNAs (miRNAs) regulated during this response have remained yet ...undetermined. Here, we show that TGF-β transcriptionally induces MIR100HG lncRNA, containing miR-100, miR-125b and let-7a in its intron, via SMAD2/3. Interestingly, we find that although the pro-tumourigenic miR-100 and miR-125b accordingly increase, the amount of anti-tumourigenic let-7a is unchanged, as TGF-β also induces LIN28B inhibiting its maturation. Notably, we demonstrate that inactivation of miR-125b or miR-100 affects the TGF-β-mediated response indicating that these miRNAs are important TGF-β effectors. We integrate AGO2-RIP-seq with RNA-seq to identify the global regulation exerted by these miRNAs in PDAC cells. Transcripts targeted by miR-125b and miR-100 significantly overlap and mainly inhibit p53 and cell-cell junctions' pathways. Together, we uncover that TGF-β induces an lncRNA, whose encoded miRNAs, miR-100, let-7a and miR-125b play opposing roles in controlling PDAC tumourigenesis.
Somatostatin analogs have been shown to control the growth of well-differentiated metastatic neuroendocrine tumors. Their effect on overall survival is a matter of debate. We analyzed the prognostic ...significance of early treatment with octreotide LAR and of hepatic tumor load in the PROMID trial cohort.
Between 2001 and 2008, 85 treatment-naïve patients were randomly assigned to monthly octreotide LAR 30 mg or placebo until tumor progression or death. Post-study treatment was at the discretion of the investigator. Upon disease progression, 38 out of 43 placebo patients (88.4%) received octreotide LAR. For survival, patients were followed until May 2014.
Forty-eight out of 85 patients (56.5%) died. In 38 patients (79.2%), death was tumor related. The median overall survival (84.7 and 83.7 months) was only slightly different in patients assigned to octreotide and placebo HR = 0.83 (95% CI: 0.47-1.46); p = 0.51. The median overall survival was 84.7 months for all 85 patients, 107.6 months in the low-tumor-load (n = 64) and 57.5 months in the high-tumor-load (n = 21) subgroups HR = 2.49 (95% CI: 1.36-4.55); p = 0.002. There was a trend towards improved overall survival in patients with a low hepatic tumor load receiving octreotide compared to placebo 'median not reached' and 87.2 months; HR = 0.59 (95% CI: 0.29-1.2); p = 0.142.
The extent of tumor burden is a predictor for shorter survival. Overall survival was similar in patients receiving octreotide LAR or placebo treatment at randomization. Crossover of the majority of placebo patients to octreotide LAR may have confounded the data on overall survival.
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