Nanoluciferase-based complementation assays to monitor activation, modulation and signaling of receptor tyrosine kinases (RTKs)

Receptor tyrosine kinases (RTKs) are transmembrane receptors activated by a wide diversity of growth factors, cytokines or hormones. They ensure multiple roles in cellular processes, including proliferation, differentiation and survival. They are also crucial drivers of development and progression of multiple cancer types, and represent important drug targets. Generally, ligand binding induces dimerization of RTK monomers, which induces auto-/transphosphorylation of tyrosine residues on the intracellular tails leading to the recruitment of adaptor proteins and modifying enzymes to promote and modulate various downstream signaling pathways. This chapter details easy, rapid, sensitive and versatile methods based on split Nanoluciferase complementation technology (NanoBiT) to monitor activation and modulation of two models of RTKs (EGFR and AXL) through the measurement of their dimerization and the recruitment of the adaptor protein Grb2 (SH2 domain-containing growth factor receptor-bound protein 2) and the receptor-modifying enzyme, the ubiquitin ligase Cbl.

Nanoluciferase-based methods to monitor activation, modulation and trafficking of atypical chemokine receptors

Chemokines regulate directed cell migration, proliferation and survival and are key components in various physiological and pathological processes. They exert their functions by interacting with seven-transmembrane domain receptors that signal through G proteins (GPCRs). Atypical chemokine receptors (ACKRs) play important roles in the chemokine-receptor network by regulating chemokine bioavailability for the classical receptors through chemokine sequestration, scavenging or transport. Currently, this subfamily of receptors comprises four members: ACKR1, ACKR2, ACKR3 and ACKR4. They differ notably from the classical chemokine receptors by their inability to elicit G protein-mediated signaling, which precludes the use of classical assays relying on the activation of G proteins and related downstream secondary messengers to investigate ACKRs. There is therefore a need for alternative approaches to monitor ACKR activation, modulation and trafficking. This chapter details sensitive and versatile methods based on Nanoluciferase Binary Technology (NanoBiT) and Nanoluciferase Bioluminescence Resonance Energy Transfer (NanoBRET) to monitor ACKR2 and ACKR3 activity through the measurement of β-arrestin and GRK recruitment, and receptor trafficking, including internalization and delivery to early endosomes.

Protocol for derivation of organoids and patient-derived orthotopic xenografts from glioma patient tumors

Tumor organoids and patient-derived orthotopic xenografts (PDOXs) are some of the most valuable pre-clinical tools in cancer research. In this protocol, we describe efficient derivation of organoids and PDOX models from glioma patient tumors. We provide detailed steps for organoid culture, intracranial implantation, and detection of tumors in the brain. We further present technical adjustments for standardized functional assays and drug testing.

For complete details on the use and execution of this protocol, please refer to Golebiewska et al. (2020).

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Organoids can be generated from diverse glioma patient tumors

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High-grade glioma organoids give rise to patient-derived orthotopic xenografts

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Serial transplantation in vivo allows for consistent expansion of human tumor cells

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The adapted protocol for reconstitution of uniform organoids for functional assays

Patient-derived organoids and orthotopic xenografts of primary and recurrent gliomas represent relevant patient avatars for precision oncology

Patient-based cancer models are essential tools for studying tumor biology and for the assessment of drug responses in a translational context. We report the establishment a large cohort of unique organoids and patient-derived orthotopic xenografts (PDOX) of various glioma subtypes, including gliomas with mutations in IDH1, and paired longitudinal PDOX from primary and recurrent tumors of the same patient. We show that glioma PDOXs enable long-term propagation of patient tumors and represent clinically relevant patient avatars that retain histopathological, genetic, epigenetic, and transcriptomic features of parental tumors. We find no evidence of mouse-specific clonal evolution in glioma PDOXs. Our cohort captures individual molecular genotypes for precision medicine including mutations in IDH1, ATRX, TP53, MDM2/4, amplification of EGFR, PDGFRA, MET, CDK4/6, MDM2/4, and deletion of CDKN2A/B, PTCH, and PTEN. Matched longitudinal PDOX recapitulate the limited genetic evolution of gliomas observed in patients following treatment. At the histological level, we observe increased vascularization in the rat host as compared to mice. PDOX-derived standardized glioma organoids are amenable to high-throughput drug screens that can be validated in mice. We show clinically relevant responses to temozolomide (TMZ) and to targeted treatments, such as EGFR and CDK4/6 inhibitors in (epi)genetically defined subgroups, according to MGMT promoter and EGFR/CDK status, respectively. Dianhydrogalactitol (VAL-083), a promising bifunctional alkylating agent in the current clinical trial, displayed high therapeutic efficacy, and was able to overcome TMZ resistance in glioblastoma. Our work underscores the clinical relevance of glioma organoids and PDOX models for translational research and personalized treatment studies and represents a unique publicly available resource for precision oncology.

Liposomes as tunable platform to decipher the antitumor immune response triggered by TLR and NLR agonists

Liposomes are powerful tools for the optimization of peptides and adjuvant composition in cancer vaccines. Here, we take advantage of a liposomal platform versatility to develop three vaccine candidates associating a peptide from HA influenza virus protein as CD4 epitope, a peptide from HPV16 E7 oncoprotein as CD8 epitope and TLR4, TLR2/6 or NOD1 agonists as adjuvant. Liposomal vaccine containing MPLA (TLR4 liposomes), are the most effective treatment against the HPV-transformed orthotopic lung tumor mouse model, TC-1. This vaccine induces a potent Th1-oriented antitumor immunity, which leads to a significant reduction in tumor growth and a prolonged survival of mice, even when injected after tumor appearance. This efficacy is dependent on CD8⁺ T cells. Subcutaneous injection of this treatment induces the migration of skin DCs to draining lymph nodes. Interestingly, TLR2/6 liposomes trigger a weaker Th1-immune response which is not sufficient for the induction of a prolonged antitumor activity. Although NOD1 liposome treatment results in the control of early tumor growth, it does not extend mice survival. Surprisingly, the antitumor activity of NOD1 vaccine is not associated with a specific adaptive immune response. This study shows that our modulable platform can be used for the strategical development of vaccines.

N-Heterocyclic Carbene-Polyethylenimine Platinum Complexes with Potent in Vitro and in Vivo Antitumor Efficacy

The current interest for platinum N-heterocyclic carbene complexes in cancer research stems from their impressive toxicity reported against a range of different human cancer cells. To date, the demonstration of their in vivo efficacy relative to that of established platinum-based drugs has not been specifically addressed. Here, we introduce an innovative approach to increase the NHC-Pt complex potency whereby multiple NHC-Pt(II) complexes are coordinated along a polyethylenimine polymer (PEI) chain. We show that such NHC-Pt(II)-PEI conjugates induce human cancer cell death in vitro and in vivo in a xenograft mouse model with no observable side effects in contrast to oxaliplatin. Additional studies indicate nucleus and mitochondria targeting and suggest various mechanisms of action compared to classical platinum-based anticancer drugs.

Platinum(iv) N-heterocyclic carbene complexes: their synthesis, characterisation and cytotoxic activity

Platinum(ii) N-heterocyclic carbene complexes have been oxidized by bromine or iodobenzene dichloride to provide the fully characterised corresponding platinum(iv) NHC complexes. Antiproliferative activities of Pt(iv) NHC complexes were assayed against several cancer cell lines and the results were correlated with respect to their stability. Mechanistic investigations revealed that mitochondrial dysfunction and ROS production were associated with the cytotoxic process induced by these compounds.

[Vemurafenib-induced toxic epidermal necrolysis]

BACKGROUND

Herein we report the first case of toxic epidermal necrolysis (TEN) occurring with use of vemurafenib.

PATIENTS AND METHODS

A 75-year-old female patient was being treated with vemurafenib for stage IV melanoma with BRAF V600E mutation. She suddenly presented fever, diffuse pruriginous maculopapular erythema, palpebral edema, palmar bulla, conjunctivitis, cheilitis and mucosal ulceration. The condition progressed towards detachment affecting 50% of the skin area. Cutaneous biopsy revealed lichenoid dermatosis, chiefly vesicular with numerous eosinophils. Direct immunofluorescence (IFD) was negative. Vemurafenib was the only drug to which the reaction was ascribable and we concluded on vemurafenib-induced TEN.

DISCUSSION

To our knowledge, this is the first reported case of vemurafenib-induced TEN, but this adverse effect, although already described in the BRIM-3 study, appears rare in clinical practice. Other severe skin reactions have been described in the literature. These include a case of Stevens-Johnson syndrome in a female patient treated with vemurafenib and previously receiving ipilimumab. A more common occurrence is cutaneous reactions involving efflorescence of benign hyperkeratotic lesions, occasionally accompanied by authentic epidermal carcinoma or keratoacanthoma, and requiring regular dermatological monitoring of patients treated with vemurafenib.

CONCLUSION

If maculopapular exanthema occurs under vemurafenib, continuation of this treatment should be reassessed since the risk of progression to a more serious condition such as TEN, as seen in the present case, cannot be ruled out.