Mouse Model Of Peritoneal Carcinomatosis Research Articles

Enhanced anti-tumor efficacy with multi-transgene armed mesenchymal stem cells for treating peritoneal carcinomatosis

BackgroundMesenchymal stem cells (MSCs) have garnered significant interest for their tumor-tropic property, making them potential therapeutic delivery vehicles for cancer treatment. We have previously shown the significant anti-tumour activity in mice preclinical models and companion animals with naturally occurring cancers using non-virally engineered MSCs with a therapeutic transgene encoding cytosine deaminase and uracil phosphoribosyl transferase (CDUPRT) and green fluorescent protein (GFP). Clinical studies have shown improved response rate with combinatorial treatment of 5-fluorouracil and Interferon-beta (IFNb) in peritoneal carcinomatosis (PC). However, high systemic toxicities have limited the clinical use of such a regime.MethodsIn this study, we evaluated the feasibility of intraperitoneal administration of non-virally engineered MSCs to co-deliver CDUPRT/5-Flucytosine prodrug system and IFNb to potentially enhance the cGAS-STING signalling axis. Here, MSCs were engineered to express CDUPRT or CDUPRT-IFNb. Expression of CDUPRT and IFNb was confirmed by flow cytometry and ELISA, respectively. The anti-cancer efficacy of the engineered MSCs was evaluated in both in vitro and in vivo model. ES2, HT-29 and Colo-205 were cocultured with engineered MSCs at various ratio. The cell viability with or without 5-flucytosine was measured with MTS assay. To further compare the anti-cancer efficacy of the engineered MSCs, peritoneal carcinomatosis mouse model was established by intraperitoneal injection of luciferase expressing ES2 stable cells. The tumour burden was measured through bioluminescence tracking.ResultsFirstly, there was no changes in phenotypes of MSCs despite high expression of the transgene encoding CDUPRT and IFNb (CDUPRT-IFNb). Transwell migration assays and in-vivo tracking suggested the co-expression of multiple transgenes did not impact migratory capability of the MSCs. The superiority of CDUPRT-IFNb over CDUPRT expressing MSCs was demonstrated in ES2, HT-29 and Colo-205 in-vitro. Similar observations were observed in an intraperitoneal ES2 ovarian cancer xenograft model. The growth of tumor mass was inhibited by ~ 90% and 46% in the mice treated with MSCs expressing CDUPRT-IFNb or CDUPRT, respectively.ConclusionsTaken together, these results established the effectiveness of MSCs co-expressing CDUPRT and IFNb in controlling and targeting PC growth. This study lay the foundation for the development of clinical trial using multigene-armed MSCs for PC.

Pathological and Biological Significance of the Specific Glycan, TRA-1-60, on Aggressive Gastric Adenocarcinoma

The glycans form a unique complex on the surface of cancer cells and play a pivotal role in tumor progression, impacting proliferation, invasion, and metastasis. TRA-1-60 is a glycan that was identified as a critical marker for the establishment of fully reprogrammed inducible pluripotent stem cells. Its expression has been detected in multiple cancer tissues, including embryonal carcinoma, prostate cancer, and pancreatic cancer, but the biological and pathological characterization of TRA-1-60-expressing tumor cells remains unclear within various types of malignancies. Here, we report the biological characteristics of TRA-1-60-expressing gastric cancer cells, especially those with its cell surface expression, and the therapeutic significance of targeting TRA-1-60. The cells with cell membrane expression of TRA-1-60 were mainly observed in the invasive area of patient gastric cancer tissues and correlated with advanced stages of the disease based on histopathological and clinicopathological analyses. In vitro analysis using a scirrhous gastric adenocarcinoma line, HSC-58, which highly expresses TRA-1-60 on its plasma membrane, revealed increased stress-resistant mechanisms, supported by the upregulation of glutathione synthetase and NCF-1 (p47phox) via lipid–ROS regulatory pathways, as detected by RNA-seq analysis followed by oxidative stress gene profiling. Our in vivo therapeutic study using the TRA-1-60-targeting antibody–drug conjugate, namely, Bstrongomab-conjugated monomethyl auristatin E, showed robust efficacy in a mouse model of peritoneal carcinomatosis induced by intraperitoneal xenograft of HSC-58, by markedly reducing massive tumor ascites. Thus, targeting the specific cell surface glycan, TRA-1-60, shows a significant therapeutic impact in advanced-stage gastric cancers.

Phonozen-mediated photodynamic therapy comparing two wavelengths in a mouse model of peritoneal carcinomatosis.

This study assessed the therapeutic efficacy of intraperitoneal photodynamic therapy (PDT) using photosensitizer activation at two different wavelengths, 405 and 664nm, in a mouse model of peritoneal carcinomatosis. The dark and light cytotoxicity of chlorin e6-polyvinylpyrrolidone (Phonozen) were measured in vitro under 402 ± 14 and 670 ± 18nm LED activation in bioluminescent human gastric cancer cells, MKN45-luc. Cell viability was measured at 6h after irradiation using the PrestoBlue assay. Corresponding in vivo studies were performed in athymic nude mice by intraperitoneal injection of 1 × 106 MKN45-luc cells. PDT was performed 10 d after tumor induction and comprised intraperitoneal injection of Phonozen followed by light irradiation at 3h, delivered by a diffusing-tip optical fiber placed in the peritoneal cavity and coupled to a 405 or 664nm diode laser to deliver a total energy of 50J (20 mice per cohort). Whole-body bioluminescence imaging was used to track the tumor burden after PDT out to 130days, and 5 mice in each cohort were sacrificed at 4h post treatment to measure the acute tumor necrosis. Photosensitizer dose-dependent photocytotoxicity was higher in vitro at 405 than 664nm. In vivo, PDT reduced the tumor growth rate at both wavelengths, with no statistically significant difference. There was substantial necrosis, and median survival was significantly prolonged at both wavelengths compared with controls (46 and 46 vs. 34 days). Phonozen-mediated PDT results in significant cytotoxicity in vitro as well as tumor necrosis and prolonged survival in vivo following intraperitoneal light irradiation. Blue light was more photocytotoxic than red in vitro and had marginally higher efficacy in vivo.

Efficacy evaluation of chimeric antigen receptor-modified human peritoneal macrophages in the treatment of gastric cancer

BackgroundGastric cancer is one of the most common cancers. Peritoneal carcinomatosis (PC) appears to be the most common pattern of recurrence, and more than half of the GC patients eventually die from PC. Novel strategies for the management of patients with PC are urgently needed. Recently, rapid progress has been made in adoptive transfer therapy by using macrophages as the effector cells due to their capabilities of phagocytosis, antigen presentation, and high penetration. Here, we generated a novel macrophage-based therapy and investigated anti-tumoral effects on GC and potential toxicity.MethodsWe developed a novel Chimeric Antigen Receptor-Macrophage (CAR-M) based on genetically modifying human peritoneal macrophages (PMs), expressing a HER2-FcεR1γ-CAR (HF-CAR). We tested HF-CAR macrophages in a variety of GC models in vitro and in vivo.ResultsHF-CAR-PMs specifically targeted HER2-expressed GC, and harboured the FcεR1γ moieties to trigger engulfment. Intraperitoneal administration of HF-CAR-PMs significantly facilitated the HER2-positive tumour regression in PC mouse model and prolonged the overall survival rate. In addition, the combined use of oxaliplatin and HF-CAR-PMs exhibited significantly augment anti-tumour activity and survival benefit.ConclusionsHF-CAR-PMs could represent an exciting therapeutic option for patients with HER2-positive GC cancer, which should be tested in carefully designed clinical trials.

Gas plasma-oxidized sodium chloride acts via hydrogen peroxide in a model of peritoneal carcinomatosis.

Gas plasma technology generates reactive oxygen and nitrogen species (ROS/RNS), inducing lethal oxidative damage in tumor cells. The transfer of gas plasma-derived ROS/RNS into liquids has been proposed as an innovative anti-cancer strategy targeting peritoneal carcinomatosis (PC). However, the mechanism of action is under debate. To this end, we compared gas plasma-oxidized medical-grade sodium chloride (oxNaCl) with a concentration-matched control (cmc) of NaCl enriched with equivalent concentrations of H2O2 and NO3- in several cell lines and models of PC. Strikingly, oxNaCl and cmc performed equally well in oxidation and cytotoxic activity in tumor cells in two-dimensional cultures, three-dimensional (3D) tumor spheroids, vascularized 3D tumors grown on chicken-embryo chorioallantoic membranes, and a syngeneic PC mouse model invivo. Given the importance of immunotherapies in oncology today, we focused on immunological consequences of the treatment. Again, to a similar extent, oxNaCl and cmc increased tumor cell immunogenicity and enhanced uptake by and maturation of peripheral blood monocyte-derived dendritic cells together with an inflammatory secretion profile. Furthermore, NanoString gene expression profiling revealed immune system processes and unfolded protein response-related pathways as being linked to the observed anti-tumor effects for both oxNaCl and cmc. In conclusion, gas plasma-generated oxNaCl and cmc showed equal therapeutic efficacy in our PC-related models. In light of the many promising anti-cancer studies of gas plasma-oxidized liquids and the convenient production of corresponding cmcs in large quantities as needed in clinics, our findings may spur research lines based on low-dose oxidants in peritoneal cancer therapy.

Ligand-mediated PAI-1 inhibition in a mouse model of peritoneal carcinomatosis

SummaryPeritoneal carcinomatosis (PC) present a ubiquitous clinical conundrum in all intra-abdominal malignancies. Via functional and transcriptomic experiments of ascites-treated PC cells, we identify STAT3 as a key signaling pathway. Integrative analysis of publicly available databases and correlation with clinical cohorts (n = 7,359) reveal putative clinically significant activating ligands of STAT3 signaling. We further validate a 3-biomarker prognostic panel in ascites independent of clinical covariates in a prospective study (n = 149). Via single-cell sequencing experiments, we uncover that PAI-1, a key component of the prognostic biomarker panel, is largely secreted by fibroblasts and mesothelial cells. Molecular stratification of ascites using PAI-1 levels and STAT3 activation in ascites-treated cells highlight a therapeutic opportunity based on a phenomenon of paracrine addiction. These results are recapitulated in patient-derived ascites-dependent xenografts. Here, we demonstrate therapeutic proof of concept of direct ligand inhibition of a prognostic target within an enclosed biological space.

Abstract P044: Real-time visualization of tumor cell phenotype and microenvironmental heterogeneity enabled by a hyperspectral fluorescence microendoscope

Abstract Tumor microenvironmental heterogeneity is a major driver of treatment resistance and variability in clinical response to therapy. This heterogeneity arises from variations in cellular phenotypes populating the tumor microenvironment (TME), their spatio-temporal localization and expression of surface markers, often associated with specific biological function – stemness, metabolism, proliferation, immune activation and others. Such features are usually studied through ex vivo immunofluorescence and cytometry to identify cellular phenotypes in TME; however, they cannot be applied in vivo for real time TME analysis. Moreover, current in vivo imaging techniques fail to provide real-time high-resolution visualization of the TME. Routinely employed biopsy tissue sampling through fine needle aspirates is limited by its invasive nature and inability to provide a global and dynamic overview of the TME, thus limiting our ability to study spatiotemporal TME dynamics and identify possible features leading to potentially resistant tumor phenotypes. In this study, we demonstrate the use of a hyperspectral fluorescence microendoscope (HFME) to monitor cellular phenotypes in TME with real-time visualization and high video imaging capability (~17 fps). Current fluorescence video microscopy is limited to simultaneous imaging of no more than 2 molecular markers with potential to be expanded to ~4 markers using dichroic mirrors and point detectors; the HFME demonstrated in this study can currently resolve 6 different molecular markers, simultaneously, using a multichannel linear array detector with potential to expand to 10 or more markers. Using a cocktail of near infra-red fluorophore-antibody conjugates targeted against key molecular (surface) markers of different cells in the TME, we are able to capture real-time TME dynamics at cellular resolution in two pre-clinical models; 1) a xenograft orthotopic mouse model of peritoneal carcinomatosis (disseminated metastases within the abdominal cavity) and imaging epidermal growth factor receptor (EGFR), CD44, CA125 (MUC16), transferrin receptor, Thomsen-Friedenreich carbohydrate antigen (T antigen), and CD45, 2) A syngeneic immunocompetent KPC cell line implanted mouse model of pancreatic ductal adenocarcinoma and imaging CD3, CD4, CD8a and CD45. Imaging on these tumor models was performed pre- and post-sub-therapeutic verteporfin (benzoporphyrin derivative monoacid A) photodynamic therapy (PDT, a cytotoxic light-based therapy). PDT treatment resulted in reduction of cancer cell burden, immune cell infiltration and alterations in their relative spatial localization. The results were confirmed by histopathological validation and ex vivo immunofluorescence staining of tumor tissue sections. Collectively, these results demonstrate the capability of HFME to image cancer cell phenotypes and the tumor microenvironment, in real time in live mice. With the ability to monitor cancer growth and treatment effects at a cellular level, HFME can potentially assist in customizing therapies in a patient-specific manner. Citation Format: Mohammad A. Saad, Bryan Q. Spring, Akilan Palanisami, Eric M. Kercher, Ryan T. Lang, Jason Sutin, Zhiming Mai, Tayyaba Hasan. Real-time visualization of tumor cell phenotype and microenvironmental heterogeneity enabled by a hyperspectral fluorescence microendoscope [abstract]. In: Abstracts: AACR Virtual Special Conference: Tumor Immunology and Immunotherapy; 2021 Oct 5-6. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(1 Suppl):Abstract nr P044.

Patient-derived cell lines and orthotopic mouse model of peritoneal carcinomatosis recapitulate molecular and phenotypic features of human gastric adenocarcinoma

BackgroundGastric adenocarcinoma with peritoneal carcinomatosis (PC) is therapy resistant and leads to poor survival. To study PC in depth, there is an urgent need to develop representative PC-derived cell lines and metastatic models to study molecular mechanisms of PC and for preclinical screening of new therapies.MethodsPC cell lines were developed from patient-derived PC cells. The tumorigenicity and metastatic potential were investigated by subcutaneously (PDXs) and orthotopically. Karyotyping, whole-exome sequencing, RNA-sequencing, and functional studies were performed to molecularly define the cell lines and compare genomic and phenotypic features of PDX and donor PC cells.ResultsWe established three PC cell lines (GA0518, GA0804, and GA0825) and characterized them in vitro. The doubling times were 22, 39, and 37 h for GA0518, GA0804, and GA0825, respectively. Expression of cancer stem cell markers (CD44, ALDH1, CD133 and YAP1) and activation of oncogenes varied among the cell lines. All three PC cell lines formed PDXs. Interestingly, all three PC cell lines formed tumors in the patient derived orthotopic (PDO) model and GA0518 cell line consistently produced PC in mice. Moreover, PDXs recapitulated transcriptomic and phenotypic features of the donor PC cells. Finally, these cell lines were suitable for preclinical testing of chemotherapy and target agents in vitro and in vivo.ConclusionWe successfully established three patient-derived PC cell lines and an improved PDO model with high incidence of PC associated with malignant ascites. Thus, these cell lines and metastatic PDO model represent excellent resources for exploring metastatic mechanisms of PC in depth and for target drug screening and validation by interrogating GAC for translational studies.

Adenovirus-Mediated Inducible Expression of a PD-L1 Blocking Antibody in Combination with Macrophage Depletion Improves Survival in a Mouse Model of Peritoneal Carcinomatosis.

Immune checkpoint inhibitors (ICIs) have demonstrated remarkable efficacy in a growing number of malignancies. However, overcoming primary or secondary resistances is difficult due to pharmacokinetics issues and side effects associated with high systemic exposure. Local or regional expression of monoclonal antibodies (mAbs) using gene therapy vectors can alleviate this problem. In this work, we describe a high-capacity adenoviral vector (HCA-EFZP-aPDL1) equipped with a mifepristone-inducible system for the controlled expression of an anti-programmed death ligand 1 (PD-L1) blocking antibody. The vector was tested in an immune-competent mouse model of colorectal cancer based on implantation of MC38 cells. A single local administration of HCA-EFZP-aPDL1 in subcutaneous lesions led to a significant reduction in tumor growth with minimal release of the antibody in the circulation. When the vector was tested in a more stringent setting (rapidly progressing peritoneal carcinomatosis), the antitumor effect was marginal even in combination with other immune-stimulatory agents such as polyinosinic-polycytidylic acid (pI:C), blocking mAbs for T cell immunoglobulin, mucin-domain containing-3 (TIM-3) or agonistic mAbs for 4-1BB (CD137). In contrast, macrophage depletion by clodronate liposomes enhanced the efficacy of HCA-EFZP-aPDL1. These results highlight the importance of addressing macrophage-associated immunoregulatory mechanisms to overcome resistance to ICIs in the context of colorectal cancer.

Development of a near infrared protein nanoprobe targeting Thomsen-Friedenreich antigen for intraoperative detection of submillimeter nodules in an ovarian peritoneal carcinomatosis mouse model

The epithelial ovarian cancer is one of the most lethal gynecological malignancy due to its late diagnostic and many relapses observed after first line of treatment. Once diagnose, the most important prognostic factor is the completeness of cytoreductive surgery. To achieve this goal, surgeons have to pinpoint and remove nodules, especially the smallest nodules. Recent advances in fluorescence-guided surgery led us to develop a recombinant lectin as a nanoprobe for the microscopic detection of nodules in the peritoneal cavity of tumor-bearing mice. This lectin has an intrinsic specificity for a carcinoma-associated glycan biomarker, the Thomsen-Friedenreich antigen. In this study, after its labelling by a near infrared dye, we first demonstrated that this nanoprobe allowed indirect detection of nodules already implanted in the peritoneal cavity, through tumor microenvironment targeting. Secondly, in a protocol mimicking the scattering of cells during surgery, we obtained a direct and long-lasting detection of tumor cells in vivo. This lectin as already been described as a nanocontainer able to do targeted delivery of a therapeutic compound to carcinoma cells. Future developments will focus on the combination of the nanoprobe and nanocontainer aspects in an intraperitoneal nanotheranostic approach.

Abstract 3273: CMP-001, a virus-like particle containing immunostimulatory CpG-A, for treatment of peritoneal carcinomatosis of gastrointestinal and pancreatic cancers

Abstract Peritoneal carcinomatosis is a common form of metastasis occurring in approximately 10% of gastrointestinal and pancreatic cancers with life expectancy often less than 6-12 months. Due to the limited options for treatment of peritoneal carcinomatosis, there is a significant need for novel therapeutic strategies. We explored the therapeutic potential of CMP-001, a novel virus-like particle composed of the Qβ bacteriophage capsid protein encapsulating an immunostimulatory CpG-A oligodeoxynucleotide (CpG-A ODN) in this cancer. CpG-A ODN is a known activator of toll-like receptor 9 (TLR9), which is expressed by human and murine plasmacytoid dendritic cells (pDCs). Initial studies evaluated the effect of CMP-001 in vitro on cells obtained from the ascitic fluid of patients with peritoneal carcinomatosis. These studies demonstrated that pDCs are present in the ascitic fluid and produce IFN-α in response to CMP-001 stimulation. A mouse model of peritoneal carcinomatosis was used to further explore the therapeutic potential of CMP-001. C57BL/6 mice were challenged intraperitoneally (i.p.) with Panc02 mouse pancreatic cancer cells. On days 5, 9, and 13 post-tumor challenge mice were treated i.p. with either saline or 100 μg CMP-001. Mice treated with CMP-001 had a median survival of 35 days compared to mice treated with saline alone with a median survival of 28 days (n = 10 per group, p = 0.028). Examination of the immune response demonstrated CMP-001 induced an influx of dendritic cells (CMP- 001 8.99% ± 0.95 vs saline 4.57% ± 0.7, p = 0.0015), NK cells (CMP-001 0.26% ± 0.052 vs saline 0.087% ± 0.0085, p = 0.006), and CD4+ T cells (CMP-001 3.29% ± 0.85 vs saline 0.95% ± 0.097, p = 0.0168) into the ascitic fluid. In addition, CMP-001 induced a significant increase in antigen-experienced, effector and memory, CD11ahiCD44hi CD4+ T cells (CMP-001 54.55% ± 6.52 vs saline 28.12% ± 3.68, p = 0.0028) and CD11ahiCD8αlo CD8+ T cells (CMP-001 58.49% ± 4.47 vs saline 23.04% ± 2.86, p < 0.0001) in the ascites. These data demonstrate that CMP-001 treatment activates pDCs in the peritoneal fluid of patients with carcinomatosis. In addition, CMP-001 stimulates a robust immune response in the peritoneal cavity of mice with peritoneal carcinomatosis. This robust immune response likely contributes to the enhanced survival and decreased disease progression in these mice. Collectively, these promising preclinical results suggest that CMP-001 may have potential as an immunotherapy for the treatment of patients with peritoneal carcinomatosis and is worthy of further evaluation. Citation Format: Ann M. Miller, Caitlin Lemke-Miltner, Sue Blackwell, Ann Tomanek-Chalkley, Kristen Coleman, George Weiner, Carlos Chan. CMP-001, a virus-like particle containing immunostimulatory CpG-A, for treatment of peritoneal carcinomatosis of gastrointestinal and pancreatic cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3273.

Murine Models of Intraperitoneal Perfusion for Disseminated Colorectal Cancer

BackgroundReproduction of the perfusion used in therapy (hyperthermic intraperitoneal chemotherapy) procedures preclinically represents a valuable asset for investigating new therapeutic agents that may improve patient outcomes. This article provides technical descriptions of our execution of closed and open “coliseum” abdominal perfusion techniques in a mouse model of peritoneal carcinomatosis of colorectal cancer. Materials and MethodsBALB/c mice presenting with disseminated colorectal cancer (CT26-luciferin cells) underwent 30-min perfusions mimicking either the closed perfusion or the coliseum perfusion technique. Disease burden was monitored by bioluminescence signaling using an in vivo imaging system. Perfusion circuits consisted of single inflow lines with either a single or dual outflow line. ResultsTwelve mice presenting with disseminated disease underwent the closed perfusion technique. Surgical complications included perfusate leakage and organ constriction/suction into the outflow line(s). Nine mice underwent the coliseum perfusion technique with surgical debulking, using bipolar cauterization to remove tumors attached to the peritoneum. All mice survived the coliseum perfusion with limited intraoperative complications. ConclusionsFewer intraoperative complications were experienced with our coliseum perfusion technique than the closed perfusion. The methods described here can be used as a guideline for developing future perfusion murine models for investigating perfusion models useful for delivery of chemotherapy or other tumor-sensitization agents, including selective targeted agents, nanoparticles, and heat.

Mechanism-informed Repurposing of Minocycline Overcomes Resistance to Topoisomerase Inhibition for Peritoneal Carcinomatosis.

Mechanism-inspired drug repurposing that augments standard treatments offers a cost-effective and rapid route toward addressing the burgeoning problem of plateauing of effective therapeutics for drug-resistant micrometastases. We show that the antibiotic minocycline, by its ability to minimize DNA repair via reduced expression of tyrosyl-DNA phosphodiesterase-1 (Tdp1), removes a key process attenuating the efficacy of irinotecan, a frequently used chemotherapeutic against metastatic disease. Moreover, minocycline and irinotecan cooperatively mitigate each other's undesired cytokine inductions of VEGF and IL8, respectively, thereby reinforcing the benefits of each modality. These mechanistic interactions result in synergistic enhancement of irinotecan-induced platinum-resistant epithelial ovarian cancer cell death, reduced micrometastases in the omenta and mesentery by >75%, and an extended overall survival by 50% in a late-stage peritoneal carcinomatosis mouse model. Economic incentives and easy translatability make the repurposing of minocycline as a reinforcer of the topoisomerase class of chemotherapeutics extremely valuable and merits further investigations. Mol Cancer Ther; 17(2); 508-20. ©2017 AACR.

Hyaluronan-binding peptide for targeting peritoneal carcinomatosis.

Peritoneal carcinomatosis results from dissemination of solid tumors in the peritoneal cavity, and is a common site of metastasis in patients with carcinomas of gastrointestinal or gynecological origin. Peritoneal carcinomatosis treatment is challenging as poorly vascularized, disseminated peritoneal micro-tumors are shielded from systemic anticancer drugs and drive tumor regrowth. Here, we describe the identification and validation of a tumor homing peptide CKRDLSRRC (IP3), which upon intraperitoneal administration delivers payloads to peritoneal metastases. IP3 peptide was identified by in vivo phage display on a mouse model of peritoneal carcinomatosis of gastric origin (MKN-45P), using high-throughput sequencing of the peptide-encoding region of phage genome as a readout. The IP3 peptide contains a hyaluronan-binding motif, and fluorescein-labeled IP3 peptide bound to immobilized hyaluronan in vitro. After intraperitoneal administration in mice bearing peritoneal metastases of gastric and colon origin, IP3 peptide homed robustly to macrophage-rich regions in peritoneal tumors, including poorly vascularized micro-tumors. Finally, we show that IP3 functionalization conferred silver nanoparticles the ability to home to peritoneal tumors of gastric and colonic origin, suggesting that it could facilitate targeted delivery of nanoscale payloads to peritoneal tumors. Collectively, our study suggests that the IP3 peptide has potential applications for targeting drugs, nanoparticles, and imaging agents to peritoneal tumors.

Telomerase-specific oncolytic adenovirus expressing TRAIL suppresses peritoneal dissemination of gastric cancer.

Peritoneal dissemination is the most common condition of metastasis in gastric cancer. The survival duration of a patient with advanced stage gastric cancer, may be improved by gene therapy. In this study, we used an oncolytic adenovirus vector (Ad/TRAIL-E1) that expresses both the TRAIL and E1A genes under the control of a tumor-specific promoter. We evaluated the anti-tumor effect of Ad/TRAIL-E1 on gastric cancer cells in vitro, as well as in vivo in a xenograft peritoneal carcinomatosis mouse model. Our data showed that Ad/TRAIL-E1 induced TRAIL-mediated apoptosis in gastric cancer cell lines, but not in the normal cell lines. In addition, Ad/TRAIL-E1 significantly inhibited peritoneal metastasis and prolonged the survival of mice without treatment-related toxicity. Therefore, tumor-specific TRAIL expression from an oncolytic adenovirus vector may provide a novel therapeutic approach for the treatment of advance stage gastric cancer with peritoneal dissemination.

Gene therapy with SOCS1 for gastric cancer induces G2/M arrest and has an antitumour effect on peritoneal carcinomatosis.

Background:Suppressor of cytokine signaling1 (SOCS1) is a negative regulator of various cytokines. Recently, it was investigated as a therapeutic target in various cancers. However, the observed antitumour effects of SOCS1 cannot not be fully explained without taking inhibition of proliferation signalling into account. Our aim was to discover a new mechanism of antitumour effects of SOCS1 for gastric cancer (GC).Methods:We analysed the mechanism of antitumour effect of SOCS1 in vitro. In addition, we evaluated antitumour effect for GC using a xenograft peritoneal carcinomatosis mouse model in preclinical setting.Results:We confirmed that SOCS1 suppressed proliferation in four out of five GC cell lines. SOCS1 appeared to block proliferation by a new mechanism that involves cell cycle regulation at the G2/M checkpoint. We showed that SOCS1 influenced cell cycle-associated molecules through its interaction with ataxia telangiectasia and Rad3-related protein. The significant difference in therapeutic effects was noted in terms of the post-treatment weight and total photon count of the intra-abdominal tumours.Conclusion:Forced expression of SOCS1 revealed a heretofore-unknown mechanism for regulating the cell cycle and may represent a novel therapeutic approach for the treatment of peritoneal carcinomatosis of GC.

Improving Anti-Tumor Activity of Curcumin by Polymeric Micelles in Thermosensitive Hydrogel System in Colorectal Peritoneal Carcinomatosis Model.

In this work, we prepared an in situ gel-forming composite drug delivery system (DDS) to treat colorectal peritoneal carcinomatosis. The composite DDS was based on curcumin loaded polymeric micelles (Cur-M) and thermosensitive hydrogel. Cur-M had a particle size of 27.1 ± 1.3 nm with polydisperse index of 0.149 ± 0.017, and the drug loading and encapsulation efficiency of Cur-M were 14.82 ± 0.07 and 98.83 ± 0.45%, respectively. The prepared Cur-M in thermosensitive hydrogel system (Cur-H) was a free-flowing sol at ambient temperature, and converted into non-flowing gel at body temperature, serving as a drug depot. In vitro drug release behavior suggested that Cur-H and Cur-M could release Cur in an extent period, and Cur-H showed a slower cumulative release rate. In addition, compared with free Cur, Cur-M showed higher cytotoxicity and apoptotic induction efficiency. Furthermore, colorectal peritoneal carcinomatosis mouse model was used to evaluate the anti-tumor activity of Cur-H, and the results suggested that Cur-H could inhibit tumor growth and metastasis, and prolonged survival of tumor-bearing mice. Immunohistochemical and immunofluorescent staining of tumor tissues in each group were conducted. The results demonstrated that tumors in Cur-H group showed lower proliferation activity, more apoptotic cells, and fewer microvessels. Besides, pharmacokinetic studies of Cur-H and Cur-M by intraperitoneal administration were performed. Compared with Cur-M, Cur-H showed a higher AUC and longer t½. Thus, the above results suggested that Cur-H may have potential applications in colorectal peritoneal carcinomatosis.

Microscale receiver operating characteristic analysis of micrometastasis recognition using activatable fluorescent probes indicates leukocyte imaging as a critical factor to enhance accuracy.

Molecular-targeted probes are emerging with applications for optical biopsy of cancer. An underexplored potential clinical use of these probes is to monitor residual cancer micrometastases that escape cytoreductive surgery and chemotherapy. Here, we show that leukocytes, or white blood cells, residing in nontumor tissues--as well as those infiltrating micrometastatic lesions--uptake cancer cell-targeted, activatable immunoconjugates nonspecifically, which limits the accuracy and resolution of micrometastasis recognition using these probes. Receiver operating characteristic analysis of freshly excised tissues from a mouse model of peritoneal carcinomatosis suggests that dual-color imaging, adding an immunostain for leukocytes, offers promise for enabling accurate recognition of single cancer cells. Our results indicate that leukocyte identification improves micrometastasis recognition sensitivity and specificity from 92 to 93%--for multicellular metastases >20 to 30 μm in size--to 98 to 99.9% for resolving metastases as small as a single cell.

A novel drug delivery system of intraperitoneal chemotherapy for peritoneal carcinomatosis using gelatin microspheres incorporating cisplatin

Peritoneal carcinomatosis is a poor prognostic factor for patients with gastrointestinal, gynecologic, and pancreatic cancer. Cisplatin (CDDP) is among the most effective anti-cancer agents, although its adverse effects remain unresolved. For the treatment of peritoneal carcinomatosis with high-dose CDDP, it is necessary to design a new delivery system of CDDP that can decrease systemic toxicity and achieve a better targeted, high-dose chemotherapy. Microspheres were prepared from gelatin of a nontoxic, biodegradable material for the sustained release of CDDP. The gelatin microspheres incorporating CDDP (GM-CDDP) were injected intraperitoneally into a mouse model of peritoneal carcinomatosis; their therapeutic efficacy and adverse effects were evaluated in comparison with intraperitoneal administration of free CDDP. GM-CDDP released CDDP in the peritoneal cavity as a result of gelatin biodegradation. Mice treated with microspheres in the peritoneal cavity lived longer than mice treated with free CDDP (74 ± 23 vs 40 ± 23 days; P < .05). The mice treated with GM-CDDP also lost no weight, whereas the free CDDP group lost approximately 20% body weight (106 ± 5% vs 80 ± 7%; P < .001; body weight on day 1 = 100%). GM-CDDP significantly decreased the nephrotoxicity and hematotoxicity of CDDP. GM decreased the adverse effects of CDDP and allowed high-dose intraperitoneal chemotherapy with the control of CDDP. This technique of gradual local release may allow us to provide a high-dose, targeted, intraperitoneal chemotherapy with CDDP, resulting in enhanced anti-cancer effects. These gelatin microspheres may be useful as a drug carrier for the treatment of peritoneal carcinomatosis.

Therapeutic efficacy and toxicity of 225Ac-labelled vs. 213Bi-labelled tumour-homing peptides in a preclinical mouse model of peritoneal carcinomatosis

Targeted delivery of alpha-particle-emitting radionuclides is a promising novel option in cancer therapy. We generated stable conjugates of the vascular tumour-homing peptide F3 both with (225)Ac and (213)Bi that specifically bind to nucleolin on the surface of proliferating tumour cells. The aim of our study was to determine the therapeutic efficacy of (225)Ac-DOTA-F3 in comparison with that of (213)Bi-DTPA-F3. ID(50) values of (213)Bi-DTPA-F3 and (225)Ac-DOTA-F3 were determined via clonogenic assays. The therapeutic efficacy of both constructs was assayed by repeated treatment of mice bearing intraperitoneal MDA-MB-435 xenograft tumours. Therapy was monitored by bioluminescence imaging. Nephrotoxic effects were analysed by histology. ID(50) values of (213)Bi-DTPA-F3 and (225)Ac-DOTA-F3 were 53 kBq/ml and 67 Bq/ml, respectively. The median survival of control mice treated with phosphate-buffered saline was 60 days after intraperitoneal inoculation of 1 × 10(7) MDA-MB-435 cells. Therapy with 6 × 1.85 kBq of (225)Ac-DOTA-F3 or 6 × 1.85 MBq of (213)Bi-DTPA-F3 prolonged median survival to 95 days and 97 days, respectively. While F3 labelled with short-lived (213)Bi (t (1/2) 46 min) reduced the tumour mass at early time-points up to 30 days after treatment, the antitumour effect of (225)Ac-DOTA-F3 (t (1/2) 10 days) increased at later time-points. The difference in the fraction of necrotic cells after treatment with (225)Ac-DOTA-F3 (43%) and with (213)Bi-DTPA-F3 (36%) was not significant. Though histological analysis of kidney samples revealed acute tubular necrosis and tubular oedema in 10-30% of animals after treatment with (225)Ac-DOTA-F3 or (213)Bi-DTPA-F3, protein casts were negligible (2%), indicating only minor damage to the kidney. Therapy with both (225)Ac-DOTA-F3 and (213)Bi-DTPA-F3 increased survival of mice with peritoneal carcinomatosis. Mild renal toxicity of both constructs favours future therapeutic application.