Atanasio Pandiella

Rational payload selection enables high antitumoral efficacy of an anti-EGFR antibody-drug conjugate against ovarian tumors

The epidermal growth factor receptor (EGFR) is frequently expressed in ovarian cancer, yet its potential as a therapeutic target remains underexplored. We investigated EGFR expression and its therapeutic exploitation using antibody-drug conjugates (ADCs) based on the clinical anti-EGFR antibody cetuximab. EGFR protein and mRNA levels were evaluated in patient-derived tumors and ovarian cancer cell lines by western blotting and qPCR, and cell surface localization was analyzed by flow cytometry. Several cetuximab-based ADCs were generated using clinically validated cytotoxics: DM1, deruxtecan (DXd), and monomethyl auristatin F (MMAF), with cleavable or non-cleavable linkers. Their structural integrity, antiproliferative activity, internalization dynamics, and mechanisms of action were examined in vitro, and in vivo efficacy and pharmacokinetics were assessed in SKOV3 and OVCAR8 xenograft models. All ADCs showed successful conjugation and preserved antibody integrity. MMAF-conjugated ADCs displayed superior antiproliferative effects, particularly the cleavable cetuximab-vc-MMAF, while A2780 and PEO4, which showed low EGFR expression, were less responsive. Cetuximab alone or free MMAF were markedly less active. Mechanistic studies revealed rapid internalization and lysosomal trafficking of cetuximab-vc-MMAF, leading to G2/M arrest, increased mitotic markers, spindle defects, DNA damage, and apoptosis. In vivo, cetuximab-vc-MMAF significantly inhibited tumor growth and prolonged survival without systemic toxicity. Pharmacokinetic analyses confirmed selective intratumoral accumulation of the ADC and its payload with minimal off-target distribution. Treated tumors exhibited reduced proliferation and increased markers of mitotic arrest, DNA damage, and apoptosis. These results demonstrate that cetuximab-based EGFR-targeting ADCs exert potent and selective antitumor activity in ovarian cancer, supporting their further preclinical and clinical development.

Ocoxin Oral Solution Triggers DNA Damage and Cell Death in Ovarian Cancer

Ovarian cancer is the most fatal of all the reproductive cancers within the female population, mainly due to its late diagnosis that limits surgery and medical treatment. Classically, ovarian cancer therapy has included conventional chemotherapy, and other therapeutic approaches are now being used to treat these patients, but the outcomes of the disease are still poor. Therefore, new strategies are needed to improve life expectancy and life quality of ovarian cancer patients. Considering that, we investigated the effect of the nutritional supplement Ocoxin Oral Solution (OOS) in ovarian cancer models. OOS contains several nutritional supplements, some of them with demonstrated antitumoral action. In vitro studies showed that OOS inhibited the proliferation of several ovarian cancer cell lines, especially of those representative of the endometrioid subtype, in a time- and dose-dependent manner. A fast cell death induction after OOS treatment was observed, and when the molecular mechanisms leading to this effect were investigated, an activation of the DNA damage checkpoint was detected, as shown by activation (phosphorylation) of CHK1 and CHK2 kinases that was followed by the phosphorylation of the target protein histone H2AX. When tested in animal models of ovarian cancer, OOS reduced tumor growth without any observed secondary effects. Moreover, such reduction in tumor proliferation was caused by the induction of DNA damage as corroborated by the in vivo phosphorylation of CHK2 and Histone H2AX. Finally, OOS potentiated the action of carboplatin or olaparib, the standard of care treatments used in ovarian clinics, opening the possibility of including OOS in combination with those standard of care agents in patients with ovarian cancer.

The WNK1–ERK5 route plays a pathophysiological role in ovarian cancer and limits therapeutic efficacy of trametinib

AbstractBackgroundThe dismal prognosis of advanced ovarian cancer calls for the development of novel therapies to improve disease outcome. In this regard, we set out to discover new molecular entities and to assess the preclinical effectiveness of their targeting.MethodsCell lines, mice and human ovarian cancer samples were used. Proteome profiling of human phosphokinases, in silico genomic analyses, genetic (shRNA and CRISPR/Cas9) and pharmacological strategies as well as an ex vivo human preclinical model were performed.ResultsWe identified WNK1 as a highly phosphorylated protein in ovarian cancer and found that its activation or high expression had a negative impact on patients’ survival. Genomic analyses showed amplification of WNK1 in human ovarian tumours. Mechanistically, we demonstrate that WNK1 exerted its action through the MEK5–ERK5 signalling module in ovarian cancer. Loss of function, genetic or pharmacological experiments, demonstrated anti‐proliferative and anti‐tumoural effects of the targeting of the WNK1–MEK5–ERK5 route. Additional studies showed that this pathway modulated the anti‐tumoural properties of the MEK1/2 inhibitor trametinib. Thus, treatment with trametinib activated the WNK1–MEK5–ERK5 route, raising the possibility that this effect may limit the therapeutic benefit of ERK1/2 targeting in ovarian cancer. Moreover, in different experimental settings, including an ex vivo patient‐derived model consisting of ovarian cancer cells cultured with autologous patient sera, we show that inhibition of WNK1 or MEK5 increased the anti‐proliferative and anti‐tumour efficacy of trametinib.ConclusionsThe present study uncovers the participation of WNK1–MEK5–ERK5 axis in ovarian cancer pathophysiology, opening the possibility of acting on this pathway with therapeutic purposes. Another important finding of the present study was the activation of that signalling axis by trametinib, bypassing the anti‐tumoural efficacy of this drug. That fact should be considered in the context of the use of trametinib in ovarian cancer.