PhpC modulates G-quadruplex-RNA landscapes in human cells

Stabilizing DNA/RNA G-quadruplexes (G4s) using small molecules (ligands) has proven an efficient strategy to decipher G4 biology. Quite paradoxically, this search has also highlighted the need for finding molecules able to disrupt G4s to tackle G4-associated cellular dysfunctions. We report here on both qualitative and quantitative investigations that validate the G4-RNA-destabilizing properties of the leading compound PhpC in human cells.

[1,2,4]triazolo[4,3-a]quinoxaline as Novel Scaffold in the Imiqualines Family: Candidates with Cytotoxic Activities on Melanoma Cell Lines

Cutaneous melanoma is one of the most aggressive human cancers and is the deadliest form of skin cancer, essentially due to metastases. Novel therapies are always required, since cutaneous melanoma develop resistance to oncogenic pathway inhibition treatment. The Imiqualine family is composed of heterocycles diversely substituted around imidazo[1,2-a]quinoxaline, imidazo[1,2-a]pyrazine, imidazo[1,5-a]quinoxaline, and pyrazolo[1,5-a]quinoxaline scaffolds, which display interesting activities on a panel of cancer cell lines, especially melanoma cell lines. We have designed and prepared novel compounds based on the [1,2,4]triazolo[4,3-a]quinoxaline scaffold through a common synthetic route, using 1-chloro-2-hydrazinoquinoxaline and an appropriate aldehyde. Cyclization is ensured by an oxidation-reduction mechanism using chloranil. The substituents on positions 1 and 8 were chosen based on previous structure-activity relationship (SAR) studies conducted within our heterocyclic Imiqualine family. Physicochemical parameters of all compounds have also been predicted. A375 melanoma cell line viability has been evaluated for 16 compounds. Among them, three novel [1,2,4]triazolo[4,3-a]quinoxalines display cytotoxic activities. Compounds 16a and 16b demonstrate relative activities in the micromolar range (respectively, 3158 nM and 3527 nM). Compound 17a shows the best EC₅₀ of the novel series (365 nM), even if EAPB02303 remains the lead of the entire Imiqualine family (3 nM).

A remarkable presentation of a massive Budd-Chiari syndrome

A 59-year-old female presented to the emergency department with malaise, significant weight loss, abdominal discomfort, dyspnoea and severely swollen peripheral extremities. She had a past medical history of sickle cell anaemia, a latent tuberculosis infection and a chronic hepatitis B that was treated with PEG-interferon alpha-2 in 2008. Since 2018, she was lost to follow-up. The patient was critically ill, sarcopenic and lethargic. Clinical examination revealed icteric sclerae and a markedly distended and diffusely tender abdomen and peripheral oedemas. Her vital signs included a blood pressure of 105/64 mmHg, tachycardia of 130 bpm, hypothermia of 35.6°C and a SpO2 of 100% in ambient air. Laboratory workup demonstrated a total bilirubin of 12.9 mg/dL, AST 500 U/L, ALT 218 U/L, ALP 178 U/L and GGT 126 U/L, a thrombocytopenia of 34 x10E3/ μL, 16,01 x10E3/μL leukocytes, a CRP of 94.8 mg/L and a lactate of 10,12 mmol/L. The serum creatinine was 1.04 mg/dL, eGFR 54.1 ml/min. The INR was 2.77 and there was a severe hypoalbuminemia (22 g/L). D-dimers were >20 000 ng/ml. The patient presented also with spontaneous hypoglycaemia. A multiphasic contrast-enhanced thoracic and abdominal computed tomography (CT) was performed (figure 1). Given the results of the CT, a 2D echocardiogram was urgently requested (figure 2).

An unusual cause of portal hypertension

A 66-year-old male with a medical history of coronary artery disease presented with nonspecific symptoms of anorexia, lethargy and an increase in abdominal girth. He was diagnosed 3 months ago with chronic liver disease of undetermined aetiology. He did not smoke and was a social drinker till 4 months ago. He was taking tests showed progressive cholestatic liver enzymes (total bilirubin 1,09 mg/dL, AST 130 U/L, ALT 129 U/L, GGT 517 U/L and ALP 641 U/L) and a severe hypoalbuminemia. Laboratory workup made a metabolic, autoimmune, and viral aetiology of the suspected cirrhosis less probable. Urinalysis showed a rapidly progressive proteinuria in the nephrotic range accompanied by the presence of serum spike of monoclonal lambda light Furosemide, Aldactone, Pantoprazole, Acetylcysteine and Atorvastatin. He had no personal or familial history of liver diseases. Physical examination revealed a tender but distended abdomen and large ascites was present. The laboratory chain protein on electrophoresis with immunofixation. Doppler echocardiography revealed a hypertrophic cardiomyopathy based on diffuse left and right ventricular hypertrophy with relative apical sparing. A diagnostic paracentesis was undertaken and the results were consistent with portal hypertension (SAAG 1,6 g/ dL). Considering the concomitant presence of hypertrophic cardiomyopathy, nephrotic syndrome and a presentation of portal hypertension of undetermined aetiology in presence of a monoclonal IgG lambda light chain spike, a transjugular liver biopsy (figure 1 and 2) was performed with HVPG measurement consistent with significant portal hypertension (15 mmHg).