title: Class III β-tubulin and the cytoskeletal gateway for drug resistance in ovarian cancer.
abstract: The Class III β-tubulin isotype (βIII-tubulin) is a predictive biomarker in ovarian cancer and other solid tumor malignancies. We discovered that βIII-tubulin function is linked to two GTPases: guanylate-binding protein 1 (GBP1), which activates its function, and GNAI1, which inhibits it. This finding was demonstrated in a panel of ovarian cancer cells resistant to several chemotherapeutic agents. Using a protein microarray, we identified PIM1 as the downstream partner of GBP1, recruited into the cytoskeleton under hypoxic conditions. The clinical value of these observations was tested by performing an archive study of 98 ovarian cancer patients, which demonstrated that the βIII-tubulin -/PIM1- cohort responded to treatment, exhibiting long overall survival (OS), while βIII-tubulin +/PIM+ patients experienced poor outcomes and OS times similar to patients receiving palliation alone. βIII-tubulin expression is commonly believed responsible for paclitaxel resistance due to its enhancement of the dynamic instability of microtubules, which counteracts the activity of taxanes. In contrast, our research reveals that βIII-tubulin behaves as a gateway for prosurvival signals, such as PIM1, to move into the cytoskeleton. When cells are exposed to microenvironmental stressors, they activate this pathway by telling the cytoskeleton to incorporate PIM1 through GBP1 and βIII-tubulin, which ultimately leads to drug resistance. This discovery reveals that βIII-tubulin does not act alone but requires partners to play its role. The discovery of such protein:protein interactions underlying this prosurvival cascade makes feasible the development of therapeutic approaches using novel compounds that are capable of inhibiting the transmission of prosurvival signals into the cytoskeleton.
authors.affiliation: Laboratory of Antineoplastic Pharmacology, Department of Obstetrics and Gynecology, Catholic University of the Sacred Heart, Rome, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: De Donato
authors.forename: Marisa
authors.initials: M
authors.lastname: Mariani
authors.forename: Lella
authors.initials: L
authors.lastname: Petrella
authors.forename: Enrica
authors.initials: E
authors.lastname: Martinelli
authors.forename: Gian Franco
authors.initials: GF
authors.lastname: Zannoni
authors.forename: Valerio
authors.initials: V
authors.lastname: Vellone
authors.forename: Gabriella
authors.initials: G
authors.lastname: Ferrandina
authors.forename: Shohreh
authors.initials: S
authors.lastname: Shahabi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Scambia
authors.forename: Cristiano
authors.initials: C
authors.lastname: Ferlini
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D000970:Antineoplastic Agents / Q000494:pharmacology / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism / Q000502:physiology; D015687:Cell Hypoxia / Q000502:physiology; D045744:Cell Line, Tumor; D003599:Cytoskeleton / Q000378:metabolism / Q000502:physiology; D019008:Drug Resistance, Neoplasm / Q000502:physiology*; D005260:Female; D006801:Humans; D010051:Ovarian Neoplasms / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D011237:Predictive Value of Tests; D011379:Prognosis; D051573:Proto-Oncogene Proteins c-pim-1 / Q000502:physiology / Q000627:therapeutic use; D012189:Retrospective Studies; D014404:Tubulin / Q000502:physiology* / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D014408:Biomarkers, Tumor; D014404:Tubulin; C496634:PIM1 protein, human; D051573:Proto-Oncogene Proteins c-pim-1