Acta Biomaterialia

Glutamine metabolism targeting liposomes for synergistic chemosensitization and starvation therapy in ovarian cancer

Platinum-based chemotherapy is a first-line therapeutic regimen against ovarian cancer (OC); however, the therapeutic potential is always reduced by glutamine metabolism. Herein, a valid strategy of inhibiting glutamine metabolism was proposed to cause tumor starvation and chemosensitization. Specifically, reactive oxygen species-responsive liposomes were developed to co-deliver cisplatin (CDDP) and bis-2-(5-phenylacetamido-1,3,4-thiadiazol-2-yl) ethyl sulfide (BPTES) [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to CDDP by reducing glutathione generation to prevent CDDP detoxification, suppressing ATP production to avoid CDDP efflux, hindering nucleotide synthesis to aggravate DNA damage induced by CDDP, and blocking mammalian target of rapamycin (mTOR) signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs. STATEMENT OF SIGNIFICANCE: This work proposed a valid strategy of inhibiting glutamine metabolism to cause tumor starvation and chemosensitization. Specifically, ROS-responsive liposomes were developed to co-deliver cisplatin CDDP and BPTES [C@B LPs]. The C@B LPs induced effective tumor cell starvation and significantly sensitized OC cells to cisplatin by reducing glutathione generation to prevent cisplatin detoxification, suppressing ATP production to avoid cisplatin efflux, hindering nucleotide synthesis to aggravate DNA damage induced by cisplatin, and blocking mTOR signaling to promote cell apoptosis. More importantly, C@B LPs remarkably inhibited tumor growth in vivo and reduced the side effects. Taken together, this study provided a successful strategy of synergistic chemosensitization and starvation therapy escalating the rate of therapeutic success in OCs.

Collagen fiber density observed in metastatic ovarian cancer promotes tumor cell adhesion

Collagen type I, a key structural component of the extracellular matrix (ECM), is frequently altered in cancer, with altered fiber organization at the primary tumor site linked to metastasis and poor patient outcomes. Here, we demonstrate that collagen fibers are also altered in metastatic sites such as the omentum of patients with high-grade serous ovarian cancer (HGSOC). Specifically, we observed a significant increase in fiber density, alignment, and width. To determine if the increase in fiber density supports metastasis, we used a semi-interpenetrating methacrylated gelatin (gelMA) network in combination with increasing fibrillar collagen. Cancer cells had significantly increased adhesion as collagen fiber density increased. To determine the responsible mechanisms, we used orthogonal systems to examine 1) the different adhesion peptides exposed in collagen (GFOGER) and gelatin (RGD), and 2) the physical structure of fibers. Cells had minimal response to GFOGER, either alone or in combination with RGD, suggesting that increased adhesion did not result from this collagen-specific interaction. Cell adhesion was significantly higher on electrospun PCL-gelatin fibers compared to flat PCL-gelatin substrates, suggesting that increased cell adhesion resulted from fiber structure. We next investigated the cellular mechanisms involved in increased adhesion on gelMA/coll and found that actin polymerization, but not myosin II contractility, was needed. We further demonstrated that cells on fibrous gels had more robust actin polymerization, and that this resulted in greater adhesion strength. Combined, these results suggest that the increase in collagen fibers with tumor metastasis will support the development of additional metastases. STATEMENT OF SIGNIFICANCE: This work advances the evaluation of the matrisome of the omentum, the most common metastatic site in advanced ovarian cancer by characterizing how collagen fibers change with disease progression. To examine the effect of collagen fibers on metastasis, we utilized a suite of in vitro biomaterials to identify a novel role for collagen fibers in supporting cell adhesion through increased actin dynamics during nascent adhesion formation, which results in increased adhesion strength at later times.

Suicide gene delivery by morphology-adaptable enantiomeric peptide assemblies for combined ovarian cancer therapy

Suicide gene therapy is a promising therapeutic model for ovarian cancer (OC), while suffering from poor gene delivery and limited therapeutic efficacy. To address this concern, here we reported the GSH-responsive morphology-transformable enantiomeric peptide assemblies as delivering vehicles for suicide genes and co-delivery of paclitaxel (PTX). Connecting a lipid-like amphiphile and a hydrophilic arginine segment through disulfide bonds led to the enantiomeric peptides. The enantiomeric peptide assemblies are able to simultaneously uptake plasmid DNA (pDNA) and PTX based on electrostatic and hydrophobic interactions. The resulting co-assemblies underwent GSH-responsive disulfide cleavage and thereby promoting their assembly from nanoparticles to nanofibers, leading to the co-release of pDNA and PTX. Cellular and animal studies confirmed the co-delivery of pDNA and PTX into OC cells and the cell apoptosis by the enantiomeric peptides. In addition, in vitro and in vivo experiments supported the advanced uptake and cytotoxicity for L-type peptide vehicles by OC cells, and their great potential for OC-imaging, growth-inhibition and apoptosis-induction compared to D-counterpart. Our results demonstrate that the GSH-responsive morphology-transformable chiral peptide assemblies accurately and simultaneously release suicide genes and chemodrugs at tumor sites, thus providing a new strategy for the development of delivering vehicles for suicide gene and establishment of new therapeutic models for ovarian cancer. STATEMENT OF SIGNIFICANCE: Appropriate delivery carriers are essential for the clinical translation of cancer gene therapy, including the emerging suicide gene therapy. By combining the advantages of morphological transformable vehicles with the chirality peptides towards their bioactivity, we developed the GSH-responsive morphology-transformable enantiomeric peptide assemblies as delivering vehicles for suicide genes and co-delivery of paclitaxel. The GSH-responsive assembly of the enantiomeric peptides allows for precise release of plasmid DNA and paclitaxel in cancer cells, and promotes the formation of nanofibrils that facilitate gene entering nuclei for transfection. The enantiomeric peptide-based vehicles show the chirality-dependent capability for inducing cell apoptosis and inhibiting tumor growth. Our findings demonstrate a new strategy for developing therapeutic models for ovarian cancer.

α3 integrin-binding peptide-functionalized polymersomes loaded with volasertib for dually-targeted molecular therapy for ovarian cancer

Ovarian cancer (OC) is a high-mortality malignancy in women with a five-year survival rate of 30-40%. There is an urgent need to develop high-efficacy and low toxic treatments for OC. Herein, we report an appealing strategy that combines α

Folate-mediated targeted PLK1 inhibition therapy for ovarian cancer: A comparative study of molecular inhibitors and siRNA therapeutics

PLK1 is a promising target for clinical treatment of diverse malignancies including ovarian cancer (OC), in which PLK1 over-expression is often correlated with poor prognosis and short survival. PLK1 can be blocked with small molecular inhibitors like volasertib (Vol) or silenced with PLK1-specific siRNA (siPLK1), hence effectively suppressing tumor growth. Surprisingly, despite intensive work on molecular inhibitor and siRNA therapeutics, there is no direct comparison between them reported for targeted tumor therapy. Herein, we employing folate as a ligand and polymersomes as a nanovehicle performed a comparative study on Vol and siPLK1 in inhibiting OC in vitro and in vivo. Folate-targeted polymersomal Vol and siPLK1 (termed as FA-Ps-Vol and FA-Ps-siPLK1, respectively) were both nano-sized and stable, and displayed an optimal FA density of 20% for SKOV-3 cells. Notably, FA-Ps-Vol and FA-Ps-siPLK1 exhibited an IC

Two-pronged microenvironmental modulation of metal-oxidase cascade catalysis and metabolic intervention for synergistic tumor immunotherapy

Codelivery of adavosertib and olaparib by tumor-targeting nanoparticles for augmented efficacy and reduced toxicity

Ovarian cancer (OC) ranks first among gynecologic malignancies in terms of mortality. The benefits of poly (ADP-ribose) polymerase (PARP) inhibitors appear to be limited to OC with BRCA mutations. Concurrent administration of WEE1 inhibitors (eg, adavosertib (Ada)) and PARP inhibitors (eg, olaparib (Ola)) effectively suppress ovarian tumor growth regardless of BRCA mutation status, but is poorly tolerated. Henceforth, we aimed to seek a strategy to reduce the toxic effects of this combination by taking advantage of the mesoporous polydopamine (MPDA) nanoparticles with good biocompatibility and high drug loading capacity. In this work, we designed a tumor-targeting peptide TMTP1 modified MPDA-based nano-drug delivery system (TPNPs) for targeted co-delivery of Ada and Ola to treat OC. Ada and Ola could be effectively loaded into MPDA nanoplatform and showed tumor microenvironment triggered release behavior. The nanoparticles induced more apoptosis in OC cells, and significantly enhanced the synergy of combination therapy with Ada plus Ola in murine OC models. Moreover, the precise drug delivery of TPNPs towards tumor cells significantly diminished the toxic side effects caused by concurrent administration of Ada and Ola. Co-delivery of WEE1 inhibitors and PARP inhibitors via TPNPs represents a promising approach for the treatment of OC. STATEMENT OF SIGNIFICANCE: Combination therapy of WEE1 inhibitors (eg, Ada) with PARP inhibitors (eg, Ola) effectively suppress ovarian tumor growth regardless of BRCA mutation status. However, poor tolerability limits its clinical application. To address this issue, we construct a tumor-targeting nano-drug delivery system (TPNP) for co-delivery of Ada and Ola. The nanoparticles specifically target ovarian cancer and effectively enhance the antitumor effect while minimizing undesired toxic side effects. As the first nanomedicine co-loaded with a WEE1 inhibitor and a PARP inhibitor, TPNP-Ada-Ola may provide a promising and generally applicable therapeutic strategy for ovarian cancer patients.

Assessing the roles of collagen fiber morphology and matrix stiffness on ovarian cancer cell migration dynamics using multiphoton fabricated orthogonal image-based models

Ovarian cancer remains the deadliest of the gynecological cancers, where this arises from poor screening and imaging tools that can detect early disease, and also limited understanding of the structural and functional aspects of the tumor microenvironment. To gain insight into the underlying cellular dynamics, we have used multiphoton excited fabrication to create Second Harmonic Generation (SHG) image-based orthogonal models from collagen/GelMA that represent both the collagen matrix morphology and stiffness (∼2-8 kPa) of normal ovarian stroma and high grade serous ovarian cancers (HGSOC). These scaffolds are used to study migration/cytoskeletal dynamics of normal (IOSE) and ovarian cancer (OVCA433) cell lines. We found that the highly aligned fiber morphology of HGSOC promotes aspects of motility (motility coefficient, motility, and focal adhesion expression) through a contact guidance mechanism and that stiffer matrix further promotes these same processes through a mechanosensitive mechanism, where these trends were similar for both normal and cancer cells. However, cell specific differences were found on these orthogonal models relative to those providing only morphology, showing the importance of presenting both morphology and stiffness cues. Moreover, we found increased cadherin expression and decreased cell alignment only for cancer cells on scaffolds of intermediate modulus suggesting different stiffness-dependent mechanotransduction mechanisms are engaged. This overall approach affords decoupling the roles of matrix morphology, stiffness and cell genotype and affords hypothesis testing of the factors giving rise to disease progression and metastasis. Further, more established fabrication techniques cannot simultaneously reproduce both the 3D collagen fiber morphology and stiffness. STATEMENT OF SIGNIFICANCE: Ovarian cancer metastasizes when lesions are small, where cells exfoliate from the surface of the ovary and reattach at distal sites in the peritoneum. The adhesion/migration dynamics are not well understood and there is a need for new 3D in vitro models of the extracellular matrix to study the biology. Here we use multiphoton excited crosslinking to fabricate ECM orthogonal models that represent the collagen morphology and stiffness in human ovarian tissues. These are then used to study ovarian cancer cell migration dynamics and we found that contact guidance and a mechanosensitive response and cell genotype all combine to affect the behavior. These models provide insight into disease etiology and progression not readily possible by other fabrication methods.