Genes tested in molecular analysis and references

Supplementary Figure Legends 1-2 from Somatostatin Receptor sst2 Decreases Cell Viability and Hormonal Hypersecretion and Reverses Octreotide Resistance of Human Pituitary Adenomas

Supplementary Figure 2 from Somatostatin Receptor sst2 Decreases Cell Viability and Hormonal Hypersecretion and Reverses Octreotide Resistance of Human Pituitary Adenomas

PFS6 and PFS12 depending of the in intention-to-treat or per protocole analyses as investigator or central review analyses.

Meningioma genes analyses The coding exons and exon-intron boundaries of 13 genes (NF2, AKT1, SMO, KLF4, TRAF7, PIK3CA, SUFU, SMARCB1, SMARCE1, CDKN2A, CDKN2B, PTEN and TERT was sequenced using the Custom QIAseq targeted DNA Panel (Qiagen, Germany) following the manufacturer's instructions. These genes were chosen according the most recent publication on whole genome sequencing or exome sequencing of meningiomas5. TheQIAseq targeted DNA panel utilizes Unique Molecular Indices (UMI)

Recurrent or high-grade meningiomas are an unmet medical need. Recently, we demonstrated that targeting mTOR by everolimus was relevant both in vitro and in humans. However, everolimus induces an AKT activation that may impact the anti-proliferative effect of the drug. Moreover, the MAP kinase pathway was shown to be involved in meningioma tumorigenesis. We therefore targeted both the Pi3k-AKT-mTOR and MAP kinase pathways by using combinations of the Pi3k inhibitor alpelisib and the MEK inhibitor trametinib. Our study was performed in vitro on the human meningioma cell lines and on a large series of primary cultures providing from 63 freshly operated meningiomas including 35 WHO grade 1, 23 grade 2, and five grade 3, half of which presented a NF2 genomic alteration. Alpelisib induced a higher inhibitory effect on cell viability and proliferation than everolimus in all cell lines and 32 randomly selected tumors no matter the genomic status, the histological subtype or grade. Trametinib also strongly inhibited cell proliferation and induced AKT activation. Combined treatment with alpelisib plus trametinib reversed the AKT activation induced by trametinib and induced an additive inhibitory effect irrespective of the cell lines or tumor features. Co-targeting pathways seems promising and may be considered particularly for aggressive meningioma.

Forty percent of somatotroph tumors harbor recurrent activating GNAS mutations, historically called the gsp oncogene. In gsp-negative somatotroph tumors, GNAS expression itself is highly variable; those with GNAS overexpression most resemble phenotypically those carrying the gsp oncogene. GNAS is monoallelically expressed in the normal pituitary due to methylation-based imprinting. We hypothesize that changes in GNAS imprinting of gsp-negative tumors affect GNAS expression levels and tumorigenesis. We characterized the GNAS locus in two independent somatotroph tumor cohorts: one of 23 tumors previously published (PMID: 31883967) and classified by pan-genomic analysis, and a second with 82 tumors. Multi-omics analysis of the first cohort identified a significant difference between gsp-negative and gsp-positive tumors in the methylation index at the known differentially methylated region (DMR) of the GNAS A/B transcript promoter, which was confirmed in the larger series of 82 tumors. GNAS allelic expression was analyzed using a polymorphic Fok1 cleavage site in 32 heterozygous gsp-negative tumors. GNAS expression was significantly reduced in the 14 tumors with relaxed GNAS imprinting and biallelic expression, compared to 18 tumors with monoallelic expression. Tumors with relaxed GNAS imprinting showed significantly lower SSTR2 and AIP expression levels. Altered A/B DMR methylation was found exclusively in gsp-negative somatotroph tumors. 43% of gsp-negative tumors showed GNAS imprinting relaxation, which correlated with lower GNAS, SSTR2 and AIP expression, indicating lower sensitivity to somatostatin analogues and potentially aggressive behavior.

Abstract Purpose: Aggressive meningiomas that progress after surgery/radiotherapy represent an unmet medical need. Strong and constant expression of SSTR2A receptors and activation of the Pi3K/Akt/mTOR pathway have been demonstrated in meningiomas. The combination of everolimus, an mTOR inhibitor, and octreotide, a somatostatin agonist, has shown additive antitumor effect in vitro. The phase II CEVOREM trial investigated the efficacy of this combination on recurrent meningiomas. Patients and Methods: Patients with documented recurrent tumor progression ineligible for further surgery/radiotherapy were eligible to receive octreotide (30 mg/d, day 1) and everolimus (10 mg/d, days 1–28). The primary endpoint was the 6-month progression-free survival rate (PFS6). The secondary endpoints were overall survival, response rate, tumor growth rate according to central review, and safety. Results: A total of 20 patients were enrolled, including 2 with World Health Organization (WHO) grade I tumors, 10 with WHO grade II tumors, and 8 with WHO grade III tumors; furthermore, 4 patients harbored NF2 germline mutation. The overall PFS6 was 55% [95% confidence interval (CI), 31.3%–73.5%], and overall 6- and 12-month survival rates were 90% (95% CI, 65.6%–97.4%) and 75% (95% CI, 50.0%–88.7%), respectively. A major decrease (>50%) was observed in the growth rate at 3 months in 78% of tumors. The median tumor growth rate decreased from 16.6%/3 months before inclusion to 0.02%/3 months at 3 months (P < 0.0002) and 0.48%/3 months at 6 months after treatment (P < 0.0003). Conclusions: The combination of everolimus and octreotide was associated with clinical and radiological activity in aggressive meningiomas and warrants further studies. Decrease in the tumor volume growth rate should be considered a complementary and sensitive endpoint to select potentially effective drugs for recurrent meningiomas.

Recent discoveries of multiple driver mutations open promising perspectives for targeted therapies in meningioma. Nevertheless, iterative recurrences of most aggressive meningiomas as extended skull base meningiomas are not systematically operated and histologically documented. This suggests the interest and the relevance of liquid biopsy in meningiomas. In a proof-of-concept study, we detected the NF2 mutation in 2 of 6 cell-free plasma DNAs and 1 of 1 cerebrospinal fluid (CSF) from high-grade recurrent cases, suggesting that identification of the driver mutation in blood and CSF is today feasible. Liquid biopsy could be an interesting tool to adapt the targeted therapy in meningiomas in the near future.

Although there is evidence of a significant rise of neuroendocrine neoplasms (NENs) incidence, current treatments are largely insufficient due to somewhat poor knowledge of these tumours. Despite showing differentiated features, NENs exhibit therapeutic resistance to most common treatments, similar to other cancers in many instances. Molecular mechanisms responsible for this resistance phenomenon are badly understood. We aimed at identifying signalling partners responsible of acquired resistance to treatments in order to develop novel therapeutic strategies. We engineered QGP-1 cells resistant to current leading treatments, the chemotherapeutic agent oxaliplatin and the mTor inhibitor everolimus. Cells were chronically exposed to the drugs and assessed for acquired resistance by viability assay. We used microarray-based kinomics to obtain highthroughput kinase activity profiles from drug sensitive vs resistant cells and identified 'hit' kinases hyperactivated in drug-resistant cells, including kinases from FGFR family, cyclin-dependant kinases and PKCs in oxaliplatin-resistant (R-Ox) QGP-1 cells. We then validated these 'hit' kinases and observed that ERK signalling is specifically enhanced in QGP-1 R-Ox cells. Finally, we assessed drug-resistant cells sensitivity to pharmacological inhibition of 'hit' kinases or their signalling partners. We found that FGFR inhibition markedly decreased ERK signalling and cell viability in QGP-1 R-Ox cells. These results suggest that the FGFR/ERK axis is hyperactivated in response to oxaliplatin-based chemotherapeutic strategy. Thus, this sensitive approach, based on the study of kinome activity, allows identifying potential candidates involved in drug resistance in NENs and may be used to broadly investigate markers of NENs therapeutic response.

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Dihydropryimidine dehydrogenase (DPD) deficiency is a pharmacogenetic syndrome associated with severe or lethal toxicities with oral capecitabine. Usually, patients with history of 5-FU-based therapy with no signs for life-threatening toxicities are considered as not DPD-deficient individuals who can be safely treated next with capecitabine if required. Here we describe the case of a woman originally treated with standard FEC100 protocol for metastatic breast cancer with little severe toxicities but grade-3 mucosities that were quickly resolved by symptomatic treatment. When switched to capecitabine + vinorelbine combo, extremely severe toxicities with fatal outcome were unexpectedly observed. Pharmacogenetic investigations were performed on cytidine deaminase and DPYD, and showed that this patient was heterozygous for the 2846A>T mutation on the DPYD gene. DPD phenotyping (i.e., uracil plasma levels >250 ng/ml, dihydrouracil/uracil ratio <0.5) confirmed that this patient was profoundly DPD deficient. Differences in fluoropyrimidine dosing between FEC100 (i.e., 500 mg/m(2) 5-FU) and capecitabine (i.e., 2250 mg daily) could explain why initial 5-FU-based protocol did not lead to life-threatening toxicities, whereas capecitabine rapidly triggered toxic death. Overall, this case report suggests that any toxicity, even when not life threatening, should be considered as a warning signal for possible underlying profound DPD deficiency syndrome, especially with low-dose protocols.

Abstract Cytarabine (Ara-C) is the backbone for treating accute myeloid leukemia (AML). As most nucleoside analogs, Ara-C is metabolized in the liver by an exclusive enzymatic step driven by cytidine deaminase (CDA). CDA is a ubiquitous enzyme that proved to be highly polymorphic, with activities in patients ranging from poor metabolizer (PM) to ultra metabolizer (UM). To date, deregulated CDA has been evidenced as a culprit for life-threatening toxicities with gemcitabine. Little evidences have been collected thus far about the possible role erratic CDA could further play with Ara-C. Here, we investigated whether deregulations affecting CDA could be at the origin of unexpectedly severe, and sometimes lethal, toxicities with Ara-C in patients with AML. In this clinical observational study we determined CDA activity levels and searched for CDA genetic polymorphisms in 58 adult patients (25F, 33M, mean age 63 ±15 years) hospitalized for AML and scheduled for induction therapy. All patients were treated following current standard care by Ara-C-containing regimen (i.e., 7+3 protocol) and monitored for toxicity (CTCAEv4 grading) and response. Efficacy was evaluated one-month after starting the induction protocol. Mean CDA activity in the studied population was 3.14 ± 3 U/mg. No relationship was found between CDA phenotype and genotype (i.e., 79A>C polymorphism). A total of 20 patients (43%) displayed severe toxicities (i.e. grade-3 and above) upon administration, including 3 unrecoverable grade-5 toxicities (5%). Relationship between CDA activity and severe toxicity was investigated using ROC analysis. We observed that the incidence of CDA deficiency was much higher in AML patients (40%) than what we previously observed in patients with solid tumors. A cut-off value in CDA ≤ 2 U/mg was associated with increased risk of experiencing severe/lethal toxicities with 74% sensitivity and 65% specificity. Among the 20 patients with severe toxicities, 14 (72 %) were categorized as PM. Importantly, patients who experienced lethal toxicities were all profoundly PM patients. CR was achieved in 35 patients (60%), CRI achieved in 4 patients (7%) whereas 16 patients (27%) failed to respond (PD). No relationship was evidenced between CDA status and response, however regardless of the karyotype we observed that PM patients tended to have longer PFS (278 vs. 517 days) and OS (570 days vs. not reached) as compared with EM patients. Overall this proof-of-concept study strongly suggests that CDA status could be a relevant marker for predicting clinical outcome in patients treated with Ara-C, especially treatment-induced toxicities. A prospective study including full PK and pharmacogenetics support is currently ongoing in our institute to confirm these observations. Should the role CDA plays be confirmed, this marker could be used as a covariate to customize Ara-C dosing in AML patients. Citation Format: Raphaelle Fanciullino, Laure Farnault, Mélanie Donnette, Vadim Ivanov, Geoffroy Venton, Joseph Ciccolini, Yael Berda-Haddad, Catherine Roche, L'Houcine Ouafik, Bruno Lacarelle, Regis Costello. CDA predicts life-threatening toxicities in AML patients treated with cytarabine [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3898.

The GNAS postzygotic mosaic activating mutations involved in fibrous dysplasia and McCune-Albright syndrome (MAS) are not detectable in leukocytes by Sanger sequencing. Digital droplet polymerase chain reaction detects GNAS mutations in 7 of 12 patients (58.3%) suspected to have fibrous dysplasia/MAS from whole blood DNA, and in 4 of 5 patients (80%) from circulating cell-free DNA.

Therapeutic management of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is challenging. The mammalian target of rapamycin (mTOR) inhibitor everolimus recently obtained approval from the Food and Drug Administration for the treatment of patients with advanced pancreatic neuroendocrine tumors (pNETs). Despite its promising antitumor efficacy observed in cell lines, clinical benefit for patients is unsatisfactory. The limited therapeutic potential of everolimus in cancer cells has been attributed to Akt activation due to feedback loops relief following mTOR inhibition. Combined inhibition of Akt might then improve everolimus antitumoral effect. In this regard, the somatostatin analog (SSA) octreotide has been shown to repress the PI3K/Akt pathway in some tumor cell lines. Moreover, SSAs are well tolerated and routinely used to reduce symptoms caused by peptide release in patients carrying functional GEP-NETs. We have recently established and characterized primary cultures of human pNETs and demonstrated the anti-proliferative effects of both octreotide and pasireotide. In this study, we aim at determining the antitumor efficacy of everolimus alone or in combination with the SSAs octreotide and pasireotide in primary cultures of pNETs. Everolimus reduced both Chromogranin A secretion and cell viability and upregulated Akt activity in single treatment. Its anti-proliferative and anti-secretory efficacy was not improved combined with the SSAs. Both SSAs did not overcome everolimus-induced Akt upregulation. Furthermore, caspase-dependent apoptosis induced by SSAs was lost in combined treatments. These molecular events provide the first evidence supporting the lack of marked benefit in patients co-treated with everolimus and SSA.

Pegvisomant (PEG), an antagonist of growth hormone (GH)-receptor (GHR), normalizes insulin-like growth factor 1 (IGF1) oversecretion in most acromegalic patients unresponsive to somatostatin analogs (SSAs) and/or uncontrolled by transsphenoidal surgery. The residual GH-secreting tumor is therefore exposed to the action of circulating PEG. However, the biological effect of PEG at the pituitary level remains unknown. To assess the impact of PEG in vitro on the hormonal secretion (GH and prolactin (PRL)), proliferation and cellular viability of eight human GH-secreting tumors in primary cultures and of the rat somatolactotroph cell line GH4C1. We found that the mRNA expression levels of GHR were characterized in 31 human GH-secreting adenomas (0.086 copy/copy β-Gus) and the GHR was identified by immunocytochemistry staining. In 5/8 adenomas, a dose-dependent inhibition of GH secretion was observed under PEG with a maximum of 38.2±17% at 1μg/mL (P<0.0001 vs control). A dose-dependent inhibition of PRL secretion occurred in three mixed GH/PRL adenomas under PEG with a maximum of 52.8±11.5% at 10μg/mL (P<0.0001 vs control). No impact on proliferation of either human primary tumors or GH4C1 cell line was observed. We conclude that PEG inhibits the secretion of GH and PRL in primary cultures of human GH(/PRL)-secreting pituitary adenomas without effect on cell viability or cell proliferation.

BACKGROUND & AIMS:The KRAS gene is mutated in most pancreatic ductal adenocarcinomas (PDAC). Expression of this KRAS oncoprotein in mice is sufficient to initiate carcinogenesis but not progression to cancer. Activation of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K) is required for KRAS for induction and maintenance of PDAC in mice. The somatostatin receptor subtype 2 (sst2) inhibits PI3K, but sst2 expression is lost during the development of human PDAC. We investigated the effects of sst2 loss during KRAS-induced PDAC development in mice. METHODS:We analyzed tumor growth in mice that expressed the oncogenic form of KRAS (KRAS(G12D)) in pancreatic precursor cells, as well as sst2+/- and sst2-/-, and in crossed KRAS(G12D);sst2+/- and KRAS(G12D);sst2-/- mice. Pancreatic tissues and acini were collected and assessed by histologic, immunoblot, immunohistochemical, and reverse-transcription polymerase chain reaction analyses. We also compared protein levels in paraffin-embedded PDAC samples from patients vs heathy pancreatic tissues from individuals without pancreatic cancer. RESULTS:In sst2+/- mice, PI3K was activated and signaled via AKT (PKB; protein kinase B); when these mice were crossed with KRAS(G12D) mice, premalignant lesions, tumors, and lymph node metastases developed more rapidly than in KRAS(G12D) mice. In crossed KRAS(G12D);sst2+/- mice, activation of PI3K signaling via AKT resulted in activation of nuclear factor-κB (NF-κB), which increased KRAS activity and its downstream pathways, promoting initiation and progression of neoplastic lesions. We found this activation loop to be mediated by PI3K-induced production of the chemokine CXCL16. Administration of a CXCL16-neutralizing antibody to KRAS(G12D) mice reduced activation of PI3K signaling to AKT and NF-κB, blocking carcinogenesis. Levels of CXCL16 and its receptor CXCR6 were significantly higher in PDAC tissues and surrounding acini than in healthy pancreatic tissues from mice or human beings. In addition, expression of sst2 was progressively lost, involving increased PI3K activity, in mouse lesions that expressed KRAS(G12D) and progressed to PDAC. CONCLUSIONS:Based on analyses of mice, loss of sst2 from pancreatic tissues activates PI3K signaling via AKT, leading to activation of NF-κB, amplification of oncogenic KRAS signaling, increased expression of CXCL16, and pancreatic tumor formation. CXCL16 might be a therapeutic target for PDAC.

To test the role of wtPIT-1 (PITWT) or PIT-1 (R271W) (PIT271) in somatolactotroph cells, we established, using inducible lentiviral vectors, sublines of GH4C1 somatotroph cells that allow the blockade of the expression of endogenous PIT-1 and/or the expression of PITWT or PIT271, a dominant negative mutant of PIT-1 responsible for Combined Pituitary Hormone Deficiency in patients. Blocking expression of endogenous PIT-1 induced a marked decrease of cell proliferation. Overexpressing PITWT twofold led also to a dose-dependent decrease of cell proliferation that was accompanied by cell death. Expression of PIT271 induced a strong dose-dependent decrease of cell proliferation accompanied by a very pronounced cell death. These actions of PIT271 are independent of its interaction/competition with endogenous PIT-1, as they were unchanged when expression of endogenous PIT-1 was blocked. All these actions are specific for somatolactotroph cells, and could not be observed in heterologous cells. Cell death induced by PITWT or by PIT271 was accompanied by DNA fragmentation, but was not inhibited by inhibitors of caspases, autophagy or necrosis, suggesting that this cell death is a caspase-independent apoptosis. Altogether, our results indicate that under normal conditions PIT-1 is important for the maintenance of cell proliferation, while when expressed at supra-normal levels it induces cell death. Through this dual action, PIT-1 may play a role in the expansion/regression cycles of pituitary lactotroph population during and after lactation. Our results also demonstrate that the so-called "dominant-negative" action of PIT271 is independent of its competition with PIT-1 or a blockade of the actions of the latter, and are actions specific to this mutant variant of PIT-1.

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