Girdin Knockdown Increases Gemcitabine Chemosensitivity to Pancreatic Cancer by Modulating Autophagy

Iridium(III) carbene complexes as potent girdin inhibitors against metastatic cancers

Many cancer-driving protein targets remain undruggable due to a lack of binding molecular scaffolds. In this regard, octahedral metal complexes with unique and versatile three-dimensional structures have rarely been explored as inhibitors of undruggable protein targets. Here, we describe antitumor iridium(III) pyridinium-N-heterocyclic carbene complex 1a, which profoundly reduces the viability of lung and breast cancer cells as well as cancer patient-derived organoids at low micromolar concentrations. Compound 1a effectively inhibits the growth of non-small-cell lung cancer and triple-negative breast cancer xenograft tumors, impedes the metastatic spread of breast cancer cells, and can be modified into an antibody-drug conjugate payload to achieve precise tumor delivery in mice. Identified by thermal proteome profiling, an important molecular target of 1a in cellulo is Girdin, a multifunctional adaptor protein that is overexpressed in cancer cells and unequivocally serves as a signaling hub for multiple pivotal oncogenic pathways. However, specific small-molecule inhibitors of Girdin have not yet been developed. Notably, 1a exhibits high binding affinity to Girdin with a Kd of 1.3 μM and targets the Girdin-linked EGFR/AKT/mTOR/STAT3 cancer-driving pathway, inhibiting cancer cell proliferation and metastatic activity. Our study reveals a potent Girdin-targeting anticancer compound and demonstrates that octahedral metal complexes constitute an untapped library of small-molecule inhibitors that can fit into the ligand-binding pockets of key oncoproteins.

Nanoparticle-Mediated Therapy with miR-198 Sensitizes Pancreatic Cancer to Gemcitabine Treatment through Downregulation of VCP-Mediated Autophagy

Pancreatic ductal adenocarcinoma (PDAC) remains an extremely aggressive disease characterized by rapidly acquired multi-drug resistance, including to first-line chemotherapeutic agent gemcitabine. Autophagy is a process that is often exploited by cancer and is one of several intrinsic factors associated with resistance to gemcitabine. We have previously found that miR-198 acts as a tumor suppressor in PDAC through the targeting of factors including Valosin-containing protein (VCP). VCP has been reported to play an important role in autophagic flux. In this study, we investigated whether the repression of VCP through miR-198 administration disrupts the autophagy process and sensitizes PDAC cells to gemcitabine treatment in vitro. Moreover, we used LGA-PEI (LPNP) nanoparticles to effectively administer miR-198 to tumors in vivo, inducing tumor sensitization to gemcitabine and leading to a significant reduction in tumor burden and metastases and a concomitant downregulation of VCP expression and autophagy maturation. Our results indicate a potential therapeutic strategy for targeting gemcitabine resistant PDAC and establishes the use of LPNPs for effective therapeutic delivery of nucleic acids in vitro and in vivo.

Girdin Promotes Tumorigenesis and Chemoresistance in Lung Adenocarcinoma by Interacting with PKM2

Girdin, an Akt substrate, has been reported to promote tumorigenesis in various tumors. However, the role of Girdin in a spontaneous tumor model has not yet been explored. Here, we studied the role of Girdin in lung adenocarcinoma (LUAD) using the autochthonous mouse model and found that Girdin led to LUAD progression and chemoresistance by enhancing the Warburg effect. Mechanistically, Girdin interacted with pyruvate kinase M2 (PKM2), which played a vital role in aerobic glycolysis. Furthermore, Girdin impaired Platelet Derived Growth Factor Receptor Beta (PDGFRβ) degradation, which in turn, promoted PKM2 tyrosine residue 105 (Y105) phosphorylation and inhibited PKM2 activity, subsequently promoting aerobic glycolysis in cancer cells. Taken together, our study demonstrates that Girdin is a crucial regulator of tumor growth and may be a potential therapeutic target for overcoming the resistance of LUAD cells to chemotherapy.

Prognosis of gastric adenocarcinoma associated with girdin, Akt, and cortactin

BACKGROUND

The actin-binding protein girdin regulates tumor cell migration and invasion by maintaining actin structure. PI3K/Akt signaling is an important actin-remodeling pathway. The protein cortactin acts directly on microfilaments and promotes tumor invasion and metastasis by rearranging the cytoskeleton. However, there are few reports on the co-expression of girdin, Akt, and cortactin in gastric adenocarcinoma (GAC).

OBJECTIVES

Evaluate girdin, Akt, and cortactin expression in GAC tissues and assess their relationship to the prognosis of GAC patients.

DESIGN

Survival analysis SETTING: Medical college in China PATIENTS AND METHODS: We compared survival in 110 paraffin-preserved GAC with corresponding normal gastric mucosa tissues in relationship to girdin, Akt, and cortactin expression levels.

MAIN OUTCOME MEASURE

Expression levels of the proteins.

SAMPLE SIZE

110 RESULTS: The expression of girdin, Akt, and cortactin were all upregulated in GAC tissues compared with corresponding normal tissues (66.4% vs 36.3%, 57.3% vs 28.2% and 69.1% vs 22.7%, respectively; P<.05) and expression was mutually positive (all P<.05). Overall survival in the girdin, Akt, and cortactin high expression groups was reduced. Multivariate analysis showed that girdin, Akt, cortactin, lymph node metastasis (LNM) and TNM stages were independent factors affecting GAC patients prognosis (P<.05).

CONCLUSIONS

Girdin and cortactin may promote GAC invasion and metastasis via the PI3-K/Akt signaling pathway. Girdin, Akt, and cortactin co-expression might serve as a novel molecular target for GAC therapy and improve the prognosis of patients with this disease.

LIMITATIONS

A small sample size and lack of related research on molecular mechanisms.

CONFLICT OF INTEREST

None.