Targeting microtubules sensitizes drug resistant lung cancer cells to lysosomal pathway inhibitors

Results from a phase Ib study of telisotuzumab vedotin in combination with osimertinib in patients with c-Met protein-overexpressing, EGFR-mutated locally advanced/metastatic non-small-cell lung cancer (NSCLC) after progression on prior osimertinib

BACKGROUND

Osimertinib is the standard first-line treatment for advanced epidermal growth factor receptor (EGFR)-mutated non-small-cell lung cancer (NSCLC). However, treatment resistance is inevitable and increased c-Met protein expression correlates with resistance. Telisotuzumab vedotin (Teliso-V) is an antibody-drug conjugate that targets c-Met protein overexpression. In this article, we report the results of a phase I/Ib trial evaluating Teliso-V plus osimertinib in patients with NSCLC after progression on osimertinib.

PATIENTS AND METHODS

This multicenter, open-label study (NCT02099058) enrolled patients with advanced EGFR-mutated, c-Met protein-overexpressing, non-squamous NSCLC that had progressed on prior osimertinib. Patients received Teliso-V (intravenously, every 2 weeks) plus osimertinib (orally, 80 mg once daily). Teliso-V was evaluated at 1.6 mg/kg in a safety lead-in phase and escalated to 1.9 mg/kg. Dose expansion included both doses. Endpoints included safety and tolerability, pharmacokinetics, objective response rate (ORR), duration of response (DOR), and progression-free survival (PFS).

RESULTS

A total of 38 patients received Teliso-V (1.6 mg/kg, n = 20; 1.9 mg/kg, n = 18) plus osimertinib and were included in this analysis. No dose-limiting toxicities were observed. Most frequent any-grade treatment-emergent adverse events (TEAEs) were peripheral sensory neuropathy (50%), peripheral edema (32%), and nausea (24%). Most common grade 3/4 TEAEs were anemia (11%) and pulmonary embolism (8%). Five TEAEs led to death; none were reported as being related to Teliso-V or osimertinib. The pharmacokinetic profile of Teliso-V plus osimertinib was similar to Teliso-V monotherapy. After a median follow-up of 7.4 months, the ORR was 50.0% per independent central review (ICR) (DOR not reached), and median PFS per ICR was 7.4 months (95% confidence interval 5.4 months-not reached).

CONCLUSIONS

Teliso-V plus osimertinib had promising activity and a manageable safety profile in patients with c-Met protein-overexpressing, EGFR-mutated non-squamous NSCLC after progression on osimertinib. This combination has the potential to address an unmet medical need in this patient population.

An Agrin-YAP/TAZ Rigidity Sensing Module Drives EGFR-Addicted Lung Tumorigenesis

Despite epidermal growth factor receptor (EGFR) is a pivotal oncogene for several cancers, including lung adenocarcinoma (LUAD), how it senses extracellular matrix (ECM) rigidity remain elusive in the context of the increasing role of tissue rigidity on various hallmarks of cancer development. Here it is shown that EGFR dictates tumorigenic agrin expression in lung cancer cell lines, genetically engineered EGFR-driven mouse models, and human specimens. Agrin expression confers substrate stiffness-dependent oncogenic attributes to EGFR-reliant cancer cells. Mechanistically, agrin mechanoactivates EGFR through epidermal growth factor (EGF)-dependent and independent modes, thereby sensitizing its activity toward localized cancer cell-ECM adherence and bulk rigidity by fostering interactions with integrin β1. Notably, a feed-forward loop linking agrin-EGFR rigidity response to YAP-TEAD mechanosensing is essential for tumorigenesis. Together, the combined inhibition of EGFR-YAP/TEAD may offer a strategy to reduce lung tumorigenesis by disrupting agrin-EGFR mechanotransduction, uncovering a therapeutic vulnerability for EGFR-addicted lung cancers.

Tumor Microenvironment Landscapes Supporting EGFR-mutant NSCLC Are Modulated at the Single-cell Interaction Level by Unesbulin Treatment

Lung cancer is the leading cause of cancer deaths. Lethal pulmonary adenocarcinomas (ADC) present with frequent mutations in the EGFR. Genetically engineered murine models of lung cancer expedited comprehension of the molecular mechanisms driving tumorigenesis and drug response. Here, we systematically analyzed the evolution of tumor heterogeneity in the context of dynamic interactions occurring with the intermingled tumor microenvironment (TME) by high-resolution transcriptomics. Our effort identified vulnerable tumor-specific epithelial cells, as well as their cross-talk with niche components (endothelial cells, fibroblasts, and tumor-infiltrating immune cells), whose symbiotic interface shapes tumor aggressiveness and is almost completely abolished by treatment with Unesbulin, a tubulin binding agent that reduces B cell-specific Moloney murine leukemia virus integration site 1 (BMI-1) activity. Simultaneous magnetic resonance imaging (MRI) analysis demonstrated decreased tumor growth, setting the stage for future investigations into the potential of novel therapeutic strategies for EGFR-mutant ADCs.

SIGNIFICANCE

Targeting the TME is an attractive strategy for treatment of solid tumors. Here we revealed how EGFR-mutant landscapes are affected at the single-cell resolution level during Unesbulin treatment. This novel drug, by targeting cancer cells and their interactions with crucial TME components, could be envisioned for future therapeutic advancements.

OSGIN1 is a novel TUBB3 regulator that promotes tumor progression and gefitinib resistance in non-small cell lung cancer

BACKGROUND

Oxidative stress induced growth inhibitor 1 (OSGIN1) regulates cell death. The role and underlying molecular mechanism of OSGIN1 in non-small cell lung cancer (NSCLC) are uncharacterized.

METHODS

OSGIN1 expression in NSCLC samples was detected using immunohistochemistry and Western blotting. Growth of NSCLC cells and gefitinib-resistant cells expressing OSGIN1 or TUBB3 knockdown was determined by MTT, soft agar, and foci formation assays. The effect of OSGIN1 knockdown on in vivo tumor growth was assessed using NSCLC patient-derived xenograft models and gefitinib-resistant patient-derived xenograft models. Potentially interacting protein partners of OSGIN1 were identified using IP-MS/MS, immunoprecipitation, PLA, and Western blotting assays. Microtubule dynamics were explored by tubulin polymerization assay and immunofluorescence. Differential expression of signaling molecules in OSGIN1 knockdown cells was investigated using phospho-proteomics, KEGG analysis, and Western blotting.

RESULTS

We found that OSGIN1 is highly expressed in NSCLC tissues and is positively correlated with low survival rates and tumor size in lung cancer patients. OSGIN1 knockdown inhibited NSCLC cell growth and patient-derived NSCLC tumor growth in vivo. Knockdown of OSGIN1 strongly increased tubulin polymerization and re-established gefitinib sensitivity in vitro and in vivo. Additionally, knockdown of TUBB3 strongly inhibited NSCLC cell proliferation. Mechanistically, we found that OSGIN1 enhances DYRK1A-mediated TUBB3 phosphorylation, which is critical for inducing tubulin depolymerization. The results of phospho-proteomics and ontology analysis indicated that knockdown of OSGIN1 led to reduced propagation of the MKK3/6-p38 signaling axis.

CONCLUSIONS

We propose that OSGIN1 modulates microtubule dynamics by enhancing DYRK1A-mediated phosphorylation of TUBB3 at serine 172. Moreover, elevated OSGIN1 expression promotes NSCLC tumor growth and gefitinib resistance through the MKK3/6-p38 signaling pathway. Our findings unveil a new mechanism of OSGIN1 and provide a promising therapeutic target for NSCLC treatment in the clinic.

The uncoating of EV71 in mature late endosomes requires CD-M6PR

Enterovirus 71 (EV71) is one of the causative agents of hand-foot-and-mouth disease, which in some circumstances could lead to severe neurological diseases. Despite of its importance for human health, little is known about the early stages of EV71 infection. EV71 starts uncoating with its receptor, human scavenger receptor B2 (hSCARB2), at low pH. We show that EV71 was not targeted to lysosomes in human rhabdomyosarcoma cells overexpressing hSCARB2 and that the autophagic pathway is not essential for EV71 productive uncoating. Instead, EV71 was efficiently uncoated 30 minutes after infection in late endosomes (LEs) containing hSCARB2, mannose-6-phosphate receptor (M6PR), RAB9, bis(monoacylglycero)phosphate and lysosomal associated membrane protein 2 (LAMP2). Furthering the notion that mature LEs are crucial for EV71 uncoating, cation-dependent (CD)-M6PR knockdown impairs EV71 infection. Since hSCARB2 interacts with cation-independent (CI)-M6PR through M6P-binding sites and CD-M6PR also harbor a M6P-binding site, CD-M6PR is likely to play important roles in EV71 uncoating in LEs.

EGFR signaling pathway as therapeutic target in human cancers

Epidermal Growth Factor Receptor (EGFR) enacts major roles in the maintenance of epithelial tissues. However, when EGFR signaling is altered, it becomes the grand orchestrator of epithelial transformation, and hence one of the most world-wide studied tyrosine kinase receptors involved in neoplasia, in several tissues. In the last decades, EGFR-targeted therapies shaped the new era of precision-oncology. Despite major advances, the dream of converting solid tumors into a chronic disease is still unfulfilled, and long-term remission eludes us. Studies investigating the function of this protein in solid malignancies have revealed numerous ways how tumor cells dysregulate EGFR function. Starting from preclinical models (cell lines, organoids, murine models) and validating in clinical specimens, EGFR-related oncogenic pathways, mechanisms of resistance, and novel avenues to inhibit tumor growth and metastatic spread enriching the therapeutic portfolios, were identified. Focusing on non-small cell lung cancer (NSCLC), where EGFR mutations are major players in the adenocarcinoma subtype, we will go over the most relevant discoveries that led us to understand EGFR and beyond, and highlight how they revolutionized cancer treatment by expanding the therapeutic arsenal at our disposal.

Loss of CPAP causes sustained EGFR signaling and epithelial-mesenchymal transition in oral cancer

Higher epidermal growth factor receptor (EGFR) signaling can contribute to tumor metastasis and resistance to therapies in oral squamous cell carcinoma (OSCC). EGFR signaling can promote epithelial-mesenchymal transition (EMT) in OSCC. EMT is a process by which epithelial cells acquire invasive properties and it can contribute to tumor metastasis. Not only do the abnormal functions of microtubule and microtubule-organizing centers (MTOC) such as centrosomes lead to cancers, but also the malignant tissues are characterized by aberrant centriolar features and amplified centrosomes. Microtubule inhibition therapies increase the sensitivity to EGFR targeting drugs in various cancers. In this study, we show that the loss of expression of a microtubule/tubulin binding protein, centrosomal protein 4.1-associated protein (CPAP), which is critical for centriole biogenesis and normal functioning of the centrosome, caused an increase in the EGFR levels and its signaling and, enhanced the EMT features and invasiveness of OSCC cells. Further, depletion of CPAP enhanced the tumorigenicity of these cells in a xeno-transplant model. Importantly, CPAP loss-associated EMT features and invasiveness of multiple OSCC cells were attenuated upon depletion of EGFR in them. On the other hand, we found that CPAP protein levels were higher in EGF treated OSCC cells as well as in oral cancer tissues, suggesting that the frequently reported aberrant centriolar features of tumors are potentially a consequence, but not the cause, of tumor progression. Overall, our novel observations show that, in addition to its known indispensable role in centrosome biogenesis, CPAP also plays a vital role in suppressing tumorigenesis in OSCC by facilitating EGFR homeostasis.