Pancreatic ductal adenocarcinoma (PDAC) is extremely stroma‐rich. Cancer‐associated fibroblasts (CAFs) secrete proteins that activate survival and promote chemoresistance of cancer cells. Our results ...demonstrate that CAF secretome‐triggered chemoresistance is abolished upon inhibition of the protein synthesis mTOR/4E‐BP1 regulatory pathway which we found highly activated in primary cultures of α‐SMA‐positive CAFs, isolated from human PDAC resections. CAFs selectively express the sst1 somatostatin receptor. The SOM230 analogue (Pasireotide) activates the sst1 receptor and inhibits the mTOR/4E‐BP1 pathway and the resultant synthesis of secreted proteins including IL‐6. Consequently, tumour growth and chemoresistance in nude mice xenografted with pancreatic cancer cells and CAFs, or with pieces of resected human PDACs, are reduced when chemotherapy (gemcitabine) is combined with SOM230 treatment. While gemcitabine alone has marginal effects, SOM230 is permissive to gemcitabine‐induced cancer cell apoptosis and acts as an antifibrotic agent. We propose that selective inhibition of CAF protein synthesis with sst1‐directed pharmacological compounds represents an anti‐stromal‐targeted therapy with promising chemosensitization potential.
Synopsis
A novel drug association combining current chemotherapies with pharmacological inhibition of the Cancer‐Associated Fibroblast secretome with the somatostatin analogue SOM230 (Pasireotide), effectively reverses chemoresistance in pancreatic cancer.
The secretome of pancreatic cancer‐associated fibroblasts critically contributes to stroma‐triggered chemoresistance.
Elevated PI3K/mTOR pathway activity in pancreatic α‐SMA‐positive cancer‐associated fibroblasts contributes to high protein synthesis/secretion rates.
Inhibition of the protein synthesis mTOR/4E‐BP1 regulatory pathway in pancreatic cancer‐associated fibroblasts, with the novel somatostatin analogue SOM230 (Pasireotide), reverses tumour chemoresistance.
SOM230 selectively targets the somatostatin receptor subtype sst1 in pancreatic α‐SMA‐positive cancer‐associated fibroblasts, which is not expressed in pancreatic non‐activated α‐SMA‐negative fibroblasts or cancer cells.
The combination of chemotherapy (gemcitabine) and pharmacological inhibition of the cancer‐associated fibroblast secretome provides synergistic chemosensitization and tumour growth breakdown.
A novel drug association combining current chemotherapies with pharmacological inhibition of the Cancer‐Associated Fibroblast secretome with the somatostatin analogue SOM230 (Pasireotide), effectively reverses chemoresistance in pancreatic cancer.
Cerebral amyloid angiopathy (CAA) is an age-related small vessel disease, characterised pathologically by progressive deposition of amyloid β in the cerebrovascular wall. The Boston criteria are used ...worldwide for the in-vivo diagnosis of CAA but have not been updated since 2010, before the emergence of additional MRI markers. We report an international collaborative study aiming to update and externally validate the Boston diagnostic criteria across the full spectrum of clinical CAA presentations.
In this multicentre, hospital-based, retrospective, MRI and neuropathology diagnostic accuracy study, we did a retrospective analysis of clinical, radiological, and histopathological data available to sites participating in the International CAA Association to formulate updated Boston criteria and establish their diagnostic accuracy across different populations and clinical presentations. Ten North American and European academic medical centres identified patients aged 50 years and older with potential CAA-related clinical presentations (ie, spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes), available brain MRI, and histopathological assessment for CAA diagnosis. MRI scans were centrally rated at Massachusetts General Hospital (Boston, MA, USA) for haemorrhagic and non-haemorrhagic CAA markers, and brain tissue samples were rated by neuropathologists at the contributing sites. We derived the Boston criteria version 2.0 (v2.0) by selecting MRI features to optimise diagnostic specificity and sensitivity in a prespecified derivation cohort (Boston cases 1994–2012, n=159), then externally validated the criteria in a prespecified temporal validation cohort (Boston cases 2012–18, n=59) and a geographical validation cohort (non-Boston cases 2004–18; n=123), comparing accuracy of the new criteria to the currently used modified Boston criteria with histopathological assessment of CAA as the diagnostic standard. We also assessed performance of the v2.0 criteria in patients across all cohorts who had the diagnostic gold standard of brain autopsy.
The study protocol was finalised on Jan 15, 2017, patient identification was completed on Dec 31, 2018, and imaging analyses were completed on Sept 30, 2019. Of 401 potentially eligible patients presenting to Massachusetts General Hospital, 218 were eligible to be included in the analysis; of 160 patient datasets from other centres, 123 were included. Using the derivation cohort, we derived provisional criteria for probable CAA requiring the presence of at least two strictly lobar haemorrhagic lesions (ie, intracerebral haemorrhages, cerebral microbleeds, or foci of cortical superficial siderosis) or at least one strictly lobar haemorrhagic lesion and at least one white matter characteristic (ie, severe visible perivascular spaces in centrum semiovale or white matter hyperintensities in a multispot pattern). The sensitivity and specificity of these criteria were 74·8% (95% CI 65·4–82·7) and 84·6% (71·9–93·1) in the derivation cohort, 92·5% (79·6–98·4) and 89·5% (66·9–98·7) in the temporal validation cohort, 80·2% (70·8–87·6) and 81·5% (61·9–93·7) in the geographical validation cohort, and 74·5% (65·4–82·4) and 95·0% (83·1–99·4) in all patients who had autopsy as the diagnostic standard. The area under the receiver operating characteristic curve (AUC) was 0·797 (0·732–0·861) in the derivation cohort, 0·910 (0·828–0·992) in the temporal validation cohort, 0·808 (0·724–0·893) in the geographical validation cohort, and 0·848 (0·794–0·901) in patients who had autopsy as the diagnostic standard. The v2.0 Boston criteria for probable CAA had superior accuracy to the current Boston criteria (sensitivity 64·5% 54·9–73·4; specificity 95·0% 83·1–99·4; AUC 0·798 0·741–0854; p=0·0005 for comparison of AUC) across all individuals who had autopsy as the diagnostic standard.
The Boston criteria v2.0 incorporate emerging MRI markers of CAA to enhance sensitivity without compromising their specificity in our cohorts of patients aged 50 years and older presenting with spontaneous intracerebral haemorrhage, cognitive impairment, or transient focal neurological episodes. Future studies will be needed to determine generalisability of the v.2.0 criteria across the full range of patients and clinical presentations.
US National Institutes of Health (R01 AG26484).
Various tumors metastasize via lymph vessels and lymph nodes to distant organs. Even though tumors are hypoxic, the mechanisms of how hypoxia regulates lymphangiogenesis remain poorly characterized. ...Here, we show that hypoxia reduced vascular endothelial growth factor C (VEGF-C) transcription and cap-dependent translation via the upregulation of hypophosphorylated 4E-binding protein 1 (4E-BP1). However, initiation of VEGF-C translation was induced by hypoxia through an internal ribosome entry site (IRES)-dependent mechanism. IRES-dependent VEGF-C translation was independent of hypoxia-inducible factor 1α (HIF-1α) signaling. Notably, the VEGF-C IRES activity was higher in metastasizing tumor cells in lymph nodes than in primary tumors, most likely because lymph vessels in these lymph nodes were severely hypoxic. Overall, this transcription-independent but translation-dependent upregulation of VEGF-C in hypoxia stimulates lymphangiogenesis in tumors and lymph nodes and may contribute to lymphatic metastasis.
Display omitted
•Hypoxia increases VEGF-C protein levels•The VEGF-C 5′ UTR contains an IRES•Hypoxia in lymph vessels upregulates VEGF-C IRES activity in vivo•Hypoxic induction of VEGF-C protein levels is independent of HIF-1α
Vascular endothelial growth factor C (VEGF-C) synthesis correlates with tumor metastasis to the lymph nodes. In this study, Garmy-Susini and colleagues show that VEGF-C upregulation is induced by hypoxia through a HIF-1α-independent mechanism. The VEGF-C mRNA 5′ untranslated region contains an internal ribosome entry site (IRES) allowing ribosome recruitment during stress to promote translation when cap-dependent translation is decreased. These findings suggest that tumor cells have adopted mechanisms to ensure spreading via lymphatics in oxygen-deprived conditions when metastasizing through hypoxic lymph vessels and lymph nodes.
Pineoblastomas (PBs) are rare, aggressive pediatric brain tumors of the pineal gland with modest overall survival despite intensive therapy. We sought to define the clinical and molecular spectra of ...PB to inform new treatment approaches for this orphan cancer. Tumor, blood, and clinical data from 91 patients with PB or supratentorial primitive neuroectodermal tumor (sPNETs/CNS-PNETs), and 2 pineal parenchymal tumors of intermediate differentiation (PPTIDs) were collected from 29 centres in the Rare Brain Tumor Consortium. We used global DNA methylation profiling to define a core group of PB from 72/93 cases, which were delineated into five molecular sub-groups. Copy number, whole exome and targeted sequencing, and miRNA expression analyses were used to evaluate the clinico-pathologic significance of each sub-group. Tumors designated as group 1 and 2 almost exclusively exhibited deleterious homozygous loss-of-function alterations in miRNA biogenesis genes (
DICER1
,
DROSHA
, and
DGCR8
) in 62 and 100% of group 1 and 2 tumors, respectively. Recurrent alterations of the oncogenic
MYC-miR-17/92-RB1
pathway were observed in the RB and MYC sub-group, respectively, characterized by
RB1
loss with gain of
miR-17/92
, and recurrent gain or amplification of
MYC
. PB sub-groups exhibited distinct clinical features: group 1–3 arose in older children (median ages 5.2–14.0 years) and had intermediate to excellent survival (5-year OS of 68.0–100%), while Group RB and MYC PB patients were much younger (median age 1.3–1.4 years) with dismal survival (5-year OS 37.5% and 28.6%, respectively). We identified age < 3 years at diagnosis, metastatic disease, omission of upfront radiation, and chr 16q loss as significant negative prognostic factors across all PBs. Our findings demonstrate that PB exhibits substantial molecular heterogeneity with sub-group-associated clinical phenotypes and survival. In addition to revealing novel biology and therapeutics, molecular sub-grouping of PB can be exploited to reduce treatment intensity for patients with favorable biology tumors.
In early embryos, the DNA damage checkpoint is silent until the midblastula transition (MBT) because of maternal limiting factors of unknown identity. Here we identify the RAD18 ubiquitin ligase as ...one such factor in Xenopus. We show, in vitro and in vivo, that inactivation of RAD18 function leads to DNA damage-dependent checkpoint activation, monitored by CHK1 phosphorylation. Moreover, we show that the abundance of both RAD18 and PCNA monoubiquitylated (mUb) are developmentally regulated. Increased DNA abundance limits the availability of RAD18 close to the MBT, thereby reducing PCNAmUb and inducing checkpoint derepression. Furthermore, we show that this embryonic-like regulation can be reactivated in somatic mammalian cells by ectopic RAD18 expression, therefore conferring resistance to DNA damage. Finally, we find high RAD18 expression in cancer stem cells highly resistant to DNA damage. Together, these data propose RAD18 as a critical embryonic checkpoint-inhibiting factor and suggest that RAD18 deregulation may have unexpected oncogenic potential.
Display omitted
•DNA damage tolerance protein RAD18 is a checkpoint-limiting factor in Xenopus embryos•At low N/C ratios, RAD18 suppresses the checkpoint and induces resistance to DNA damage•There is constitutive PCNAmUb and DNA POLη recruitment to chromatin at a low N/C ratio•RAD18 is overexpressed in glioblastoma cancer stem cells
The DNA damage checkpoint is silent in the rapidly dividing cells of early Xenopus embryos. Kermi et al. find that high levels of the maternally provided DNA-damage tolerance protein RAD18 suppress checkpoint activity in early embryos. As cells divide, DNA abundance increases relative to RAD18, allowing checkpoint activation at the midblastula transition.
Background
Mammary analog secretory carcinoma (MASC) of the salivary gland has been recently described according to morphological, immunohistochemical, and molecular (ETV6‐NTRK3 translocation) ...similarities with the mammary secretory carcinoma. The most important differential diagnostic considerations of MASC are low‐grade adenocarcinoma not otherwise specified (NOS), cystadenocarcinoma, and acinic cell carcinoma (AciCC). These tumors may share an overlapping morphology with MASC, and additional immunohistochemical studies are required to reinforce the diagnosis. Mammaglobin, GCDFP‐15, and p63 staining have been reported in MASC. Our study was designed to check the specificity of these antibodies in MASC compared to other frequent tumors of salivary glands.
Methods
A series of 62 salivary gland tumors 10 MASCs, 5 adenocarcinomas NOS and 2 cystadenocarcinomas with MASC features and without ETV6 rearrangement, one low‐grade cribriform cystadenocarcinoma (LGCCC), 9 AciCCs, 10 MECs, 10 adenoid cystic carcinomas (AdeCCs), 5 polymorphous low‐grade adenocarcinomas (PLGAs), and 10 pleomorphic adenomas (PAs) was analyzed by immunohistochemistry with mammaglobin, GCDFP‐15, and p63 antibodies.
Results
Positivity for mammaglobin was observed in all MASCs, cystadenocarcinomas, LGCCC, and PLGAs, in some adenocarcinomas NOS, PAs, and MECs, rarely in AciCCs and never in AdeCCs. Positivity for GCDFP‐15 was observed in most of the tumor types except in AdeCCs. Interestingly, cytoplasmic positivity for p63 was observed in most of MASCs and PLGAs while rarely in adenocarcinomas NOS and PAs, and never in the other tumor types.
Conclusion
Our study revealed the usefulness of mammaglobin and p63 cytoplasmic staining to define which tumors are worth to be screened for ETV6 rearrangement.
Highlights • CLIPPERS is a relapsing-remitting brainstem disease of unknown origin • Sentinel lesions of primary CNS lymphoma could fit all features of CLIPPERS • Including our patient, three cases ...of CLIPPERS progressed to CNS B-cell lymphoma • CLIPPERS and CNS lymphoma are two distinct diseases or belong to the same disorder? • Further investigations are needed to determine the pathophysiology of CLIPPERS
Aims
To improve the cytological diagnosis of retinal lymphoma on vitreous fluid using improved cell collection and systematic analyses.
Methods and results
Since October 2010, we have developed and ...optimized in our department a method with which to perform the diagnosis of retinal lymphoma. The vitreous sample was collected in a tube containing RPMI‐1640 medium, decomplemented fetal bovine serum, and gentamicin. The transport and technical steps were performed at 4°C. Systematically, cytological examination with May–Grünwald–Giemsa staining and immunocytochemistry (mainly anti‐CD3, anti‐CD20 and anti‐CD68 antibodies) were performed on cytospins. Whenever possible, determination of B‐cell clonality, flow cytometry and determination of the interleukin (IL)‐10/IL‐6 ratio were performed. From October 2010 to June 2013, with this optimized protocol, 38 vitreous cytological samples from 32 patients were analysed, and a final diagnosis was possible, avoiding a biopsy, in all cases except one.
Conclusion
The preservation of vitreous fluid cells on culture medium led to the diagnosis of retinal lymphoma in 10 of 12 cases, and exclusion of this diagnosis in 26 cases. This protocol may be applied even when the delay in shipping from the surgery to the pathology departments exceeds 1 h.
PDF
