Roch-Philippe Charles

Background: Parkinson disease (PD) is a chronic progressive neurodegenerative disorder leading to motor and non-motor impairment, often resulting in severe loss of quality of life. There are symptomatic treatments without effect on the progression of PD. A disease-modifying treatment that could ideally stop the neurodegenerative process is direly needed. Monosialotetrahexosylganglioside (GM1) is a promising molecule with neuroprotective effects in preclinical models of PD and has yielded encouraging results in patients with PD in a randomized placebo-controlled trial. Talineuren (TLN) is a liposomal formulation of GM1 that has been shown to cross the blood–brain barrier in animals. We assessed the safety and pharmacokinetics (PK) of TLN in patients with PD. Methods and findings: We prospectively enrolled 12 patients with PD into a single-center, open-label phase I trial to assess the safety and tolerability of weekly infusions with TLN. The maximum suitable dose of TLN was determined by dose escalation in three patients. All three patients tolerated the predetermined maximal dose of 720 mg. Subsequently, these and nine additional patients received weekly infusions at the maximum suitable dose of 720 mg TLN over two months (1 patient stopped prematurely). PK were determined for the additional nine patients as a secondary outcome measure. C_max was reached 4 h after infusion start for all but one participant, who reached C_max after 1 h, while the median plasma half-life was reached at 12.6 h. All adverse events were continuously assessed as the primary objective and coded according to the Medical Dictionary for Regulatory Activities (MedDRA). Clinical manifestations of PD were assessed as secondary outcomes using the Movement Disorders Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), including a levodopa challenge test at baseline and end. In addition to weekly history taking, scales to measure mood, behavior, quality of life, sleepiness, non-motor symptoms of PD, and cognition were used as further secondary outcomes as well as assessing the Levodopa-Equivalent Daily Dose (LEDD). Overall, 304 adverse events (mean: 25.33; 6–75 events per patient) occurred, 267 of which were mild (mean: 22.25; 3–72 events per patient). 23 were considered related to the study treatment (0–8 events per patient). Very mild-to-severe acute infusion reactions at the second, third, or fourth administration of TLN within the first minutes of the infusion occurred in seven patients. All reported back or neck pain. Other acute infusion reactions were urticaria, plethora, nausea, and chest pain. These adverse reactions disappeared within minutes of stopping the infusion and did not recur when TLN administration was resumed at a very low rate. Beyond the fourth administration, infusions could be given at increased rates up to 370 ml/h, and no acute reaction occurred anymore. The mechanism of this acute infusion reaction remains unclear. Some patients reported mild dizziness for a few hours after TLN following many but not all administrations throughout the study. Non-motor symptoms of PD, motor parkinsonian signs off medication, and quality of life improved significantly during the treatment phase, including the MDS-UPDRS total score (mean decrease −11.09; 95% Confidence Interval [CI]; −18, −4.1; p = 0.006), the Parkinson’s disease Questionnaire-39 (PDQ-39) summary index (mean decrease −2.91; 95% CI; −4.4, −1.4; p = 0.005), and the Non-Motor Symptoms Questionnaire (NMS-Quest) (mean decrease −4.27; 95% CI; −6.5, −2.1; p = 0.009). No statistically significant improvements were seen in the Montreal Cognitive Assessment (MoCA) (mean decrease −0.73; 95% CI; −2.1, 0.62; p = 0.255), Epworth Sleepiness Scale (mean increase 0.09; 95% CI; −2.6, 2.8; p > 0.999), Beck Depression Inventory (BDI) (mean decrease −1.27; 95% CI; −3.8, 1.3; p = 0.257), and the Starkstein Apathy Scale (mean increase 0.36; 95% CI; −1.6, 2.4; p = 0.822). Dopaminergic medications remained stable during the study (LEDD mean increase 8.18; 95% CI; −7.7, 24; p = 0.423). While clinical improvements indicate a benefit associated with TLN treatment, the trial design does not allow for definite conclusions regarding efficacy. A randomized, placebo-controlled trial will be required to corroborate our exploratory findings. Conclusion: TLN is safe and well-tolerated in general. This prospective phase I trial revealed non-allergic habituating acute infusion reactions at the second, third, or fourth treatment that can be prevented by a slower rate of infusion. Importantly, the exploratory results suggest a consistent improvement of signs and symptoms of PD. Trial registration: The NEON trial is registered at the US National Institutes of Health (ClinicalTrials.gov) #NCT04976127 and in the Swiss National Clinical Trials Portal (SNCTP000004631)

Chronic proliferation is a major hallmark of tumor cells. Rapidly proliferating cancer cells are highly dependent on nutrients in order to duplicate their cell mass during each cell division. In particular, essential amino acids are indispensable for proliferating cancer cells. Their uptake across the cell membrane is tightly controlled by membrane transporters. Among those, the L-type amino acid transporter LAT1 (SLC7A5) has been repeatedly found overexpressed in a vast variety of cancers. In this review, we summarize the most recent advances in our understanding of the role of LAT1 in cancer and highlight preclinical studies and drug developments underlying the potential of LAT1 as therapeutic target.

By screening a focused library of kinase inhibitor analogues in a phenotypic co‐culture assay for angiogenesis inhibition, we identified an aminotriazine that acts as a cytostatic nanomolar inhibitor. However, this aminotriazine was found to be completely inactive in a whole‐kinome profiling assay. To decipher its mechanism of action, we used the online target prediction tool PPB2 (http://ppb2.gdb.tools), which suggested lysophosphatidic acid acyltransferase β (LPAAT‐β) as a possible target for this aminotriazine as well as several analogues identified by structure–activity relationship profiling. LPAAT‐β inhibition (IC₅₀ ≈15 nm) was confirmed in a biochemical assay and by its effects on cell proliferation in comparison with a known LPAAT‐β inhibitor. These experiments illustrate the value of target‐prediction tools to guide target identification for phenotypic screening hits and significantly expand the rather limited pharmacology of LPAAT‐β inhibitors.

Anaplastic thyroid carcinoma (ATC) is refractory to radioiodine therapy in part because of impaired iodine metabolism. We targeted the mitogen-activated protein kinase and phosphatidylinositol 3-kinase (PI3′K) pathways with the intent to induce radioiodine uptake for radioiodine treatment of ATC. Methods: Human ATC cells were used to evaluate the ability of pharmacologic inhibition of the mitogen-activated protein kinase and PI3′K pathways to induce radioiodine uptake. Thyrocyte-specific double-mutant BRAF^V600E PIK3CA^H1047R mice were treated with a MEK inhibitor followed by radioiodine treatment, and tumor burden was monitored by ultrasound imaging. Results: ATC cell lines showed an increase in sodium-iodine symporter transcription when treated with a MEK or BRAF^V600E inhibitor alone and in combination with PI3′K inhibitor. This translated into a dose-dependent elevation of iodine uptake after treatment with a MEK inhibitor alone and in combination with a PI3′K inhibitor. In vivo, MEK inhibition but not BRAF or PI3′K inhibition upregulated sodium-iodine symporter transcription. This translated into a stable reduction of tumor burden when mice were treated with a MEK inhibitor before radioiodine administration. Conclusion: This study confirms the ability of MEK inhibition to induce iodine uptake in in vitro and in vivo models of ATC. The approach of using a MEK inhibitor before radioiodine treatment could readily be translated into clinical practice and provide a much-needed therapeutic option for patients with ATC.

The L-type amino acid transporter 1 (LAT1/SLC7A5) transports essential amino acids across the plasma membrane. While LAT1 is overexpressed in a variety of human neoplasms, its expression and its role in thyroid cancer is currently unknown. Anaplastic thyroid carcinoma (ATC) is a highly aggressive malignancy for which no effective therapy exists. The purpose of this study was to explore whether the inhibition of LAT1 in ATC would affect tumor growth both in vitro and in vivo. LAT1 was pharmacologically blocked by JPH203 in human ATC and papillary thyroid cancer (PTC) cell lines. The effects on proliferation and mTORC1 activity were addressed in vitro. A genetically engineered mouse model of ATC was used to address the effect of blocking LAT1 on tumor growth in vivo. SLC7A5 transcription was measured in patient-derived ATC samples to address the clinical relevance of the findings. LAT1 block by JPH203 reduced proliferation and mTORC1 signaling in human thyroid cancer cell lines. SLC7A5 transcription was upregulated in ATC tissues derived from a genetically engineered mouse model and in ATC samples recovered from patients. JPH203 treatment induced thyroid tumor growth arrest in vivo in a fully immunocompetent mouse model of thyroid cancer. Additionally, analysis of publicly available datasets of thyroid carcinomas revealed that high LAT1 expression is associated with potentially untreatable PTC presenting reduced NIS/SLC5A5 transcription and with ATC. These preclinical results show that LAT1 inhibition is a novel therapeutic approach in the context of thyroid cancers, and more interestingly in untreatable thyroid cancers.

While the class I of PI3Ks has been deeply studied due to its clear implication in cancer development, little is known about the class II of PI3Ks. However, recent accumulation of data is now revealing that PI3KC2β, one isoform of this class of PI3Ks, may also play a role in cancer. Specifically, recent studies have suggested an implication of PI3KC2β in metastasis formation through the promotion of epithelial to mesenchymal transition (EMT). Here, we report that the overexpression of PI3KC2β in the epidermal squamous cell carcinoma (ESCC) cells A431 promotes apparent EMT transformation. We further confirm this EMT by showing modification in several biochemical markers (E-cadherin, β-catenin, Snail, Twist1 and Vimentin). Furthermore, an intracellular co-localization of E-cadherin, β-catenin and EGFR was observed. This transformation decreased EGFR signaling and the sensitivity to inhibitors targeting this receptor. To confirm our results, we have used the colon adenocarcinoma cells HT29 and induced overexpression of PI3KC2β in these cells. We could recapitulate in this model some of our major findings regarding EMT in the PI3KC2β overexpressing A431 cells. Taken together, these data support a role of PI3KC2β in promoting EMT.

PI3K signaling is frequently dysregulated in NSCLC-SQCC. In contrast to well characterized components of the PI3K signaling network contributing to the formation of SQCC, potential oncogenic effects of alterations in PIK3C2B are poorly understood. Here, a large cohort (n = 362) of NSCLC-SQCC was selectively screened for four reported somatic mutations in PIK3C2B via Sanger sequencing. In addition, two mutations leading to an amino acid exchange in the kinase domain (C1181, H1208R) were examined on a functional level. None of the mutations were identified in the cohort while well characterized hotspot PIK3CA mutations were observed at the expected frequency. Ultimately, kinase domain mutations in PI3KC2β were found to have no altering effect on downstream signaling. A set of SQCC tumors sequenced by The Cancer Genome Atlas (TCGA) equally indicates a lack of oncogenic potential of the kinase domain mutations or PIK3C2B in general. Taken together, this study suggests that PIK3C2B might only have a minor role in SQCC oncogenesis.

PIK3CA H1047R -induced paradoxical ERK activation results in resistance to BRAF V600E specific inhibitors in BRAF V600E PIK3CA H1047R double mutant thyroid tumors PIK3CAH1047R-induced paradoxical ERK activation results in resistance to BRAFV600E specific inhibitors in BRAFV600E PIK3CAH1047R double mutant thyroid tumors

Thyroid carcinomas are the most prevalent endocrine cancers. The BRAF ^V600E mutation is found in 40% of the papillary type and 25% of the anaplastic type. BRAF ^V600E inhibitors have shown great success in melanoma but, they have been, to date, less successful in thyroid cancer. About 50% of anaplastic thyroid carcinomas present mutations/amplification of the phosphatidylinositol 3’ kinase. Here we propose to investigate if the hyper activation of that pathway could influence the response to BRAF ^V600E specific inhibitors. To test this, we used two mouse models of thyroid cancer. Single mutant (BRAF ^V600E ) mice responded to BRAF ^V600E -specific inhibition (PLX-4720), while double mutant mice (BRAF ^V600E ; PIK3CA ^H1047R ) showed resistance and even signs of aggravation. This resistance was abrogated by combination with a phosphoinositide 3-kinase inhibitor. At the molecular level, we could show that this resistance was concomitant to a paradoxical activation of the MAP-Kinase pathway, which could be overturned by phosphoinositide 3-kinase inhibition in vivo in our mouse model and in vitro in human double mutant cell lines. In conclusion, we reveal a phosphoinositide 3-kinase driven, paradoxical MAP-Kinase pathway activation as mechanism for resistance to BRAF ^V600E specific inhibitors in a clinically relevant mouse model of thyroid cancer.