Intraperitoneal Cancer Research Articles

Withaferin A ameliorates ovarian cancer-induced renal damage through the regulation of expression of inflammatory cytokines

BackgroundCachexia a multifactorial syndrome is a common sequala in patients with cancer. It varies from 42 to 80% depending upon the oncological stage and is directly responsible for 30% of deaths in these patients. Previous research from our laboratory demonstrated that peritoneal ovarian cancer generated in NSG mice resulted in skeletal and cardiac muscle atrophy - leading to loss of skeletal muscle mass and strength, and cardiac dysfunction (cachexia). Treatment of mice bearing i.p. tumors with withaferin A (WFA) showed reversal of skeletal muscle and cardiac cachexia. The present study is focused on determining effects of peritoneal ovarian tumors on kidney damage and effects of WFA treatment on ameliorating kidney damage.MethodsWe generated intraperitoneal ovarian cancer by injecting female NSG mice with ovarian cancer cell line (A2780). After one week of injecting cancer cells, mice were treated with WFA (4 mg/kg) every third day, for three weeks. After 4 weeks of injection of cancer cells, the mice were sacrificed and various tissues including kidney and blood were collected, snap-frozen in liquid nitrogen, and stored at -800C. The presence of kidney biomarker creatinine, was measured in the plasma by an ELISA. The mRNA was isolated from mouse kidneys and was used to examine the expression levels of signaling proteins, inflammatory cytokines, and genes responsible for inducing cachexia (IL-1β, IL-6, TNF-α, TGF-β, GDF-15, and MYD88).ResultsOur results showed a significant increase in levels of expression of inflammatory cytokine IL-1 β (p < 0.01), IL-6 (p < 0.001), TNF-α (p < 0.001), and other related genes including TRAF6 (p < 0.01), MYD88 (p < 0.01), and GDF-15 (p = 0.005) in tumor-bearing mice compared to controls. Treatment of mice bearing tumors with WFA attenuated the increase in expression of each gene. In addition, our results showed a significant increase in creatinine levels in circulation in tumor-bearing mice compared to control mice. Treatment of tumor-bearing mice with WFA resulted in a significant decrease in plasma creatinine levels compared to tumor-bearing mice.ConclusionsOur results conclude that ovarian tumors in NSG mice caused kidney damage and renal dysfunction, which was effectively ameliorated by WFA treatment, suggesting a protective effect of WFA on kidney injury induced by ovarian cancer.

Minimally Invasive Injectable Gel for Local Immunotherapy of Liver and Gastric Cancer.

Local immunotherapy represents a promising solution for preventing tumor recurrence and metastasis post tumor surgical resection by eliminating residue tumor cells as well as eliciting tumor-specific immune responses. Minimally invasive surgery has become a mainstream surgical method worldwide due to its advantages of aesthetics and rapid postoperative recovery. Unfortunately, the currently reported local immunotherapy strategies are mostly designed to be used after open laparotomy, which go against the current surgical philosophy of minimally invasive therapy and is not suitable for clinical translation. Aiming at this problem, a minimally invasive injectable gel (MIGel) is herein reported loaded with immunotherapeutic agents for gastric and liver cancer postoperative treatment. The MIGel is formed by crosslinking between oxidized dextran (ODEX) and 4-arm polyethylene glycol hydroxylamine (4-arm PEG-ONH2) through oxime bonds, which can be injected through a clinic-used minimally invasive drainage tube and adhered tightly to the tissue. The loaded oxaliplatin (OxP) and resiquimod (R848) can be released constantly over two weeks and resulted in over 75% cure rate in orthotopic mouse gastric and liver cancer model. Collectively, a concept of minimally invasive local immunotherapy is proposed and MIGel is designed for local intraperitoneal cancer immunotherapy through minimally invasive surgery, with good clinical translation potential.

An Acceptor-Donor-Acceptor Structured Nano-Aggregate for NIR-Triggered Interventional Photoimmunotherapy of Cervical Cancer.

Compared with conventional therapies, photoimmunotherapy offers precise targeted cancer treatment with minimal damage to healthy tissues and reduced side effects, but its efficacy may be limited by shallow light penetration and the potential for tumor resistance. Here, an acceptor-donor-acceptor (A-D-A)-structured nanoaggregate is developed with dual phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), triggered by single near-infrared (NIR) light. Benefiting from strong intramolecular charge transfer (ICT), the A-D-A-structured nanoaggregates exhibit broad absorption extending to the NIR region and effectively suppressed fluorescence, which enables deep penetration and efficient photothermal conversion (η=67.94%). A suitable HOMO-LUMO distribution facilitates sufficient intersystem crossing (ISC) to convert ground-state oxygen (3O2) to singlet oxygen (1O2) and superoxide anions (·O2 -), and catalyze hydroxyl radical (·OH) generation. The enhanced ICT and ISC effects endow the A-D-A structured nanoaggregates with efficient PTT and PDT for cervical cancer, inducing efficient immunogenic cell death. In combination with clinical aluminum adjuvant gel, a novel photoimmunotherapy strategy for cervical cancer is developed and demonstrated to significantly inhibit primary and metastatic tumors in orthotopic and intraperitoneal metastasis cervical cancer animal models. The noninvasive therapy strategy offers new insights for clinical early-stage and advanced cervical cancer treatment.

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.

Staging laparoscopy with peritoneal lavage to identify peritoneal metastases and free intraperitoneal cancer cells in the management of locally advanced gastric cancer

IntroductionGastric cancer often presents in advanced stage with a significant risk for peritoneal dissemination. Staging laparoscopy can be used to detect peritoneal carcinomatosis (PC+) and free cancer cells in peritoneal lavage cytology (CY+). The current study aimed to present the outcomes of staging laparoscopy and the prognosis of PC+ and CY+ in a Swedish high-volume center. Materials and methodsA cohort study including all consecutive patients with locally advanced gastric cancer who underwent staging laparoscopy between February 2008 and October 2022. The laparoscopy findings were categorized as PC+, PC-CY+ (positive cytology without peritoneal carcinomatosis) or negative laparoscopy (PC-CY-). The primary endpoint was overall survival (OS) stratified by laparoscopy findings. The secondary endpoint was OS within each laparoscopy finding group stratified by subsequent treatment. ResultsAmong 168 patients who underwent staging laparoscopy, 78 patients (46%) had PC-CY-, 29 patients (17%) had PC-CY+ and 61 patients (36%) had PC+. Decreased OS was observed for both PC-CY+ patients (aHR 2.14, 95% CI 1.13–4.06) and PC+ patients (aHR 5.36, 95% CI 3.21–8.93), compared to PC-CY-. Patients with PC-CY+ who converted to PC-CY- after chemotherapy and underwent tumor resection seemed to have a better prognosis compared to patients with persisting PC-CY+. ConclusionsStaging laparoscopy is an important tool in the staging of locally advanced gastric cancer. Tumor resection for patients with PC-CY+ who convert to PC-CY- may lead to improved survival for these patients.

Sufficiently activated mature natural killer cells derived from peripheral blood mononuclear cells substantially enhance antitumor activity.

Peripheral blood-derived natural killer (NK) cells spontaneously lyse tumor cells without prior sensitization. However, NK cells in peripheral blood (PBNK cells) are in a resting state and exhibit inhibitory phenotypes and impaired cytotoxicity. Thus, strengthening the cytotoxic effector function of PBNK cells and improving NK cell expansion in vitro for a convenient allogeneic therapy are essential. Pure cytokine activation and expansion of NK cells (super NK [SNK])from peripheral blood mononuclear cells were studied. Markers of activated and inhibited NK cells and cytokine secretion by NK cells were examined using flow cytometry. NK cell antitumor activity in vitro was assessed using lactate dehydrogenase (LDH) cytotoxicity assay and an Incucyte real-time imaging system. Additionally, the function of SNK cells against ascites caused by ovarian cancer in NOD-Prkdc(em26Cd52)il2rg(em26Cd22)/Nju (NCG)mice was determined. In a further investigation of the differences between PBNK and SNK, the mRNA of both cells was sequenced and analyzed. Human peripheral blood mononuclear cells showed selective NK cell expansion upon cytokine activation and culture. Both SNK and PBNK cells expressed activation markers, but at different levels, and SNK cells secreted more cytokines related to cytotoxicity than PBNK cells did. Accordingly, SNK cells exhibited strong antitumor activity ex vivo and improved NCG mice survival after intraperitoneal ovarian cancer transplantation. Mechanistically, SNK cells expressed more genes associated with nucleotide metabolism, fatty acid, and ATP metabolism than PBNK cells. SNK cells derived from peripheral blood mononuclear cells have sufficiently activated mature characteristics and high antitumor activity, rendering them a highly promising and essential therapeutic approach for cancer treatment.

Prehabilitation in an Integrative Medicine Day Clinic for Patients Undergoing Neoadjuvant Treatment: Single-Center Feasibility Pilot Study.

Patients with cancer receiving neoadjuvant treatment prior to surgery are in a very stressful situation. Chemotherapy and radiation therapy put a strain on the quality of life and the pending surgery poses a relevant burden for many patients. Preparation of these patients for the intervention in terms of prehabilitation has great potential to reduce the burden of postoperative complications and may improve the clinical outcome. A prehabilitation approach also yields the possibility to address unmet patients' needs and to help them modify their lifestyle in a maintainable way. Therefore, a multimodal approach is mandatory during this critical period. The aim of this study is to assess the feasibility of prehabilitation in an integrative medicine day clinic (PRIME-DC) prior to cancer surgery at a major university clinic. PRIME-DC is considered feasible if 80% of enrolled patients are willing and able to complete at least 6 out of the 8 weekly meetings, each lasting 6.5 hours, at such a clinic. Secondary end points aim to evaluate this multimodal program. The PRIME-DC intervention combines mind-body medicine, exercise therapy, nutrition therapy, naturopathic counseling, and the application of a yarrow liver compress. Adult patients with cancer, with a primary tumor in the abdomen (including intraperitoneal cancer, stomach cancer, and extraperitoneal cancers such as pancreatic, bladder, rectal, esophageal, endometrial, ovarian, and cervical cancer) or the breast requiring a neoadjuvant oncological treatment setting are eligible to participate. The addressed cancer entities imply either an extensive surgical intervention with an expected need for prehabilitation (eg, abdominal surgery) or a neoadjuvant treatment of several months with a high burden of treatment-associated side effects (breast cancer). Adherence to the day clinic program is the primary end point being defined as presence during the day clinic session. Secondary end points are physical assessment and quality of life, together with a structured assessment of neoadjuvant treatment-associated side effects. Furthermore, to collect qualitative data voluntary participants of the day clinic will be interviewed in a semistructured way after completion of the day clinic program on each component of the study (mind-body intervention, exercise, nutrition, naturopathic counseling, and a yarrow liver compress). The procedures used in this study adhere to the tenets of the Declaration of Helsinki. As of February 2023, we enrolled 23 patients; the dominant cancer entity is breast cancer (18 enrolled patients). The presented protocol combines prehabilitation, lifestyle modification, naturopathic counseling, dietary assistance, and naturopathic treatment in an innovative and integrative way. Deutsches Register Klinischer Studien German Clinical Trials Register DRKS00028126; https://drks.de/search/de/trial/DRKS00028126. DERR1-10.2196/46765.

Folate Receptor Targeted Photodynamic Therapy: A Novel Way to Stimulate Anti-Tumor Immune Response in Intraperitoneal Ovarian Cancer.

Photodynamic therapy (PDT) has shown improvements in cancer treatment and in the induction of a proper anti-tumor immune response. However, current photosensitizers (PS) lack tumor specificity, resulting in reduced efficacy and side effects in patients with intraperitoneal ovarian cancer (OC). In order to target peritoneal metastases of OC, which overexpress folate receptor (FRα) in 80% of cases, we proposed a targeted PDT using a PS coupled with folic acid. Herein, we applied this targeted PDT in an in vivo mouse model of peritoneal ovarian carcinomatosis. The efficacy of the treatment was evaluated in mice without and with human peripheral blood mononuclear cell (PBMC) reconstitution. When mice were reconstituted, using a fractionized PDT protocol led to a significantly higher decrease in the tumor growth than that obtained in the non-reconstituted mice (p = 0.0469). Simultaneously, an immune response was reflected by an increase in NK cells, and both CD4+ and CD8+ T cells were activated. A promotion in cytokines IFNγ and TNFα and an inhibition in cytokines TGFβ, IL-8, and IL-10 was also noticed. Our work showed that a fractionized FRα-targeted PDT protocol is effective for the treatment of OC and goes beyond local induction of tumor cell death, with the promotion of a subsequent anti-tumor response.

Effect of multi-targeting bacterial gene therapy on tumour regression and survival in mouse models of ovarian and intraperitoneal cancer.

e17550 Background: With a prevalence of more than 2 million cases, a 5-year survival below 20% in stage 3 and 4, and limited treatment options, ovarian cancer represents a significant unmet medical need. We assessed the efficacy of AUP-55, a genetically engineered Lactococcus cremoris for the treatment of ovarian cancer and peritoneal carcinomatosis. We evaluated the efficacy of two AUP-55 leads producing human therapeutic proteins in situ; namely interleukin 18 (IL-18), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-12 (IL-12) and interferon alpha (IFN-A) in syngeneic intraperitoneal ID8 ovarian cancer and B16F1 melanoma models in mice. Methods: ID8-Luc-mCherry-Puro ovarian cancer model was used for survival and tumor burden by bioluminescent imaging with post-mortem pathology for all animals, whereas the B16F1 melanoma model was used solely for survival. Animals were treated daily or every other day with i.p injections of the AUP-55 leads (1e8 CFU/dose for 12-22 times). Results: In the ID8 model treatment was started 14 days after tumor implantation. Most untreated mice were terminated due to the disease progress. Treatment with AUP-55 resulted in 91.3 % survival and lower tumor load during the study duration of 81 days compared to the 0 % survival and massively increased tumor load in untreated mice. When compared to the available data from the CRO, the survival advantage was superior to, for example anti-PD1 and cisplatin treatments in the same model. In the B16F1 model, treatment with AUP-55 led to 90 % survival in comparison to 10 % untreated mice. All AUP-55 treatments were well tolerated. In the pathology post-mortem, all untreated animals had typical findings for ovarian cancer, such as ascites and high number of tumor nodules present in abdominal cavity, liver, spleen, kidney and pancreas. In the group treated with AUP-55 there were no macroscopic tumor deposits detected. Conclusions: Cytokine armed Lactococcus cremoris AUP-55 enables multimodal action. Treatment with AUP-55 suggests anti-tumor activity as a single therapeutic entity for the treatment of ovarian cancer and peritoneal carcinomatosis.

Programmed-response cross-linked nanocarrier for multidrug-resistant ovarian cancer treatment

The application of numerous chemotherapeutic drugs has been limited due to poor solubility, adverse side effects, and even multidrug resistance in patients. Polymeric micelles with reversibly cross-linked structures provide a promising solution to these issues. Herein, we optimized and synthesized programable-released disulfide cross-linked micelle (PDCM) based on our previous well-defined dendrimers to deliver the antitumor drug betulinic acid (BA) and paclitaxel (PDCM@PTX) and evaluated the therapeutic efficacy of multidrug-resistant (MDR) simulative orthotopic intraperitoneal ovarian cancer mice models. Comprehensive results demonstrated that PDCM@PTX formed stable nanoparticles able to improve the pharmacokinetic profile and circulation time of PTX, allowing for increased tumor penetration. Furthermore, in the tumor microenvironment, the programable-switches (ester bonds and disulfide cross-linking) of PDCM@PTX were cleaved by the high concentration of glutathione (tumor microenvironment) and esterase (intracellular) present in the tumor, allowing for in situ release of PTX and BA, resulting in intensive therapeutic efficacy in MDR ovarian cancer.

Targeted PDT for intraperitoneal ovarian cancer, a novel way to stimulate anti-tumoral immune response

Targeted PDT for intraperitoneal ovarian cancer, a novel way to stimulate anti-tumoral immune response

A Photoacoustic Contrast Nanoagent with a Distinct Spectral Signature for Ovarian Cancer Management.

Photoacoustic imaging (PAI) has tremendous potential for improving ovarian cancer detection. However, the lack of effective exogenous contrast agents that can improve PAI diagnosis accuracy significantly limits this application. This study presents a novel contrast nanoagent with a specific spectral signature that can be easily distinguished from endogenous chromophores in cancer tissue, allowing for high-contrast tumor visualization. Constructed as a 40nm biocompatible polymeric nanoparticle loaded with two naphthalocyanine dyes, this agent is capable of efficient ovarian tumor accumulation after intravenous injection. The developed nanoagent displays a spectral signature with two well-separated photoacoustic peaks of comparable PA intensities in the near-infrared (NIR) region at 770 and 860nm, which remain unaffected in cancer tissue following systemic delivery. In vivo experiments in mice with subcutaneous and intraperitoneal ovarian cancer xenografts validate that this specific spectral signature allows for accurate spectral unmixing of the nanoagent signal from endogenous contrast in cancer tissue, allowing for sensitive noninvasive cancer diagnosis. In addition, this nanoagent can selectively eradicate ovarian cancer tissue with a single dose of photothermal therapy by elevating the intratumoral temperature to ≈49°C upon exposure to NIR light within the 700-900nm range.

Metastatic Colon Cancer Treatment Using S100A9-Targeted Cowpea Mosaic Virus Nanoparticles.

Peritoneal metastases (PMs) occur due to the metastasis of gynecological and gastrointestinal cancers such as ovarian, colon, pancreatic, or gastric tumors. PM outgrowth is often fatal, and patients with PMs have a median survival of 6 months. Cowpea mosaic virus (CPMV) has been shown, when injected intratumorally, to act as an immunomodulator reversing the immunosuppressive tumor microenvironment, therefore turning cold tumors hot and priming systemic antitumor immunity. However, not all tumors are injectable, and PMs especially will require targeted treatments to direct CPMV toward the disseminated tumor nodules. Toward this goal, we designed and tested a CPMV nanoparticle targeted to S100A9, a key immune mediator for many cancer types indicated in cancer growth, invasiveness, and metastasis. Here, we chose to use an intraperitoneal (IP) colon cancer model, and analysis of IP gavage fluid demonstrates that S100A9 is upregulated following IP challenge. S100A9-targeted CPMV particles displaying peptide ligands specific for S100A9 homed to IP-disseminated tumors, and treatment led to improved survival and decreased tumor burden. Targeting CPMV to S100A9 improves preclinical outcomes and harbors the potential of utilizing CPMV for the treatment of IP-disseminated diseases.

Preclinical Evaluation of 225Ac-Labeled Single-Domain Antibody for the Treatment of HER2pos Cancer.

Human epidermal growth factor receptor type 2 (HER2) is overexpressed in various cancers; thus, HER2-targeting single-domain antibodies (sdAb) could offer a useful platform for radioimmunotherapy. In this study, we optimized the labeling of an anti-HER2-sdAb with the α-particle-emitter 225Ac through a DOTA-derivative. The formed radioconjugate was tested for binding affinity, specificity and internalization properties, whereas cytotoxicity was evaluated by clonogenic and DNA double-strand-breaks assays. Biodistribution studies were performed in mice bearing subcutaneous HER2pos tumors to estimate absorbed doses delivered to organs and tissues. Therapeutic efficacy and potential toxicity were assessed in HER2pos intraperitoneal ovarian cancer model and in healthy C57Bl/6 mice. [225Ac]Ac-DOTA-2Rs15d exhibited specific cell uptake and cell-killing capacity in HER2pos cells (EC50 = 3.9 ± 1.1 kBq/mL). Uptake in HER2pos lesions peaked at 3 hours (9.64 ± 1.69% IA/g), with very low accumulation in other organs (<1% IA/g) except for kidneys (11.69 ± 1.10% IA/g). α-camera imaging presented homogeneous uptake of radioactivity in tumors, although heterogeneous in kidneys, with a higher signal density in cortex versus medulla. In mice with HER2pos disseminated tumors, repeated administration of [225Ac]Ac-DOTA-2Rs15d significantly prolonged survival (143 days) compared to control groups (56 and 61 days) and to the group treated with HER2-targeting mAb trastuzumab (100 days). Histopathologic evaluation revealed signs of kidney toxicity after repeated administration of [225Ac]Ac-DOTA-2Rs15d. [225Ac]Ac-DOTA-2Rs15d efficiently targeted HER2pos cells and was effective in treatment of intraperitoneal disseminated tumors, both alone and as an add-on combination with trastuzumab, albeit with substantial signs of inflammation in kidneys. This study warrants further development of [225Ac]Ac-DOTA-2Rs15d.

Abstract 2989: FAP facilitates ovary tumorigenesis through the NF-κB/survivin funcational axis

Abstract Ovarian cancer is the deadliest gynecologic cancer, mainly attributing to lack of early diagnosis of the diseases. Current mainstay treatment for ovarian cancer is surgical removal followed by chemotherapy. Although patients initially respond well, most of patients suffer from relapse and die from metastasis. Therefore, developing successful approaches combatting metastasis is most likely to prolong patients’ survival and improve their life quality. Toward this goal, we analyzed The Cancer Genome Atlas ovarian cancer patient dataset to reach for targetable genes preferentially elevated in advanced ovarian cancer. Among them, we found that knockdown of fibroblast activation protein alpha (FAP) led to dramatic apoptosis in mesenchymal-like ovarian cancer cells. To elucidate the underlying mechanism, we performed RNAseq and identified that TNF-alpha/NF-κB signaling pathway was impaired in FAP-knockdown cells. NF-κB signaling pathway is well characterized to promote cell survival by elevating the expression of pro-survival genes. In fact, the level of survivin was diminished upon FAP-knockdown. As forced expression of survivin almost completely abrogated apoptosis elicited by FAP-knockdown and survivin inhibitor also induced robust apoptosis in ovarian cancer cells, we reason that FAP participates in ovarian cancer development by promoting cell survival through activation of NF-κB/survivin axis. With the aid of EpCAM aptamer as delivering cargo, we demonstrated that FAP siRNA was able to suppress intraperitoneal ovarian cancer development. This study suggests that FAP is an ideal therapeutic target against mesenchymal-like ovarian cancer. Citation Format: Bin Li, Shuang Huang. FAP facilitates ovary tumorigenesis through the NF-κB/survivin funcational axis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2989.

Abstract 626: Personalized immunotherapeutic platform with evidence of clinical activity in glioblastoma (IGV-001) protects mice against other lethal solid tumor challenges

Abstract Background: IGV-001 is a novel immunotherapy that combines irradiated patient-derived glioblastoma tumor cells and an antisense oligonucleotide against insulin-like growth factor type 1 receptor (IMV-001) in biodiffusion chambers (BDC). We recently reported that IGV-001-treated newly diagnosed glioblastoma patients with methylated O6-methylguanine-DNA methyl-transferase promoter had a median progression free survival of 38.4 months compared with 8.3 months in historical standard-of-care-treated patients (P=0.0008). We have now found activity with the equivalent murine approach in multiple cancer models, highlighting the transformative potential of this immunotherapeutic platform beyond glioblastoma. Methodology: We utilized several murine models including the ID8-luciferase (-Luc) intraperitoneal ovarian cancer and Hepa1-6-Luc hepatocellular carcinoma orthotopic model. BDC containing saline or 1x106 IMV-001-treated tumor cells (hereon IOV-001 and IHV-001, respectively) were implanted in flanks of C57BL/6 mice and explanted 48 h later, as per glioblastoma clinical protocol. Tumor challenge for all models was conducted 28d after chamber implantation. Mice were monitored for survival and tumor growth, as determined by bioluminescence intensity. Cytokine assays and immunophenotyping were conducted. Results: 60% of IOV-001-treated mice were alive 58d post-tumor challenge, compared to only 19% of mice in the saline group (MST=37d, p=0.004). In the Hepa1-6 model, 50% of IHV-001-treated mice were alive by 100d post-tumor challenge (MST = 60.5d). In comparison, there were no survivors in the saline group beyond 28d (MST = 18d; p = 0.004). Most of the long-term survivors had undetectable tumor; a fraction showed some level of tumor burden which rose and fell, demonstrating immune control. Circulating IFNγ was significantly higher in IOV-001-treated mice compared to controls on 1d post-tumor challenge (p&amp;lt;0.001) and trended higher in those receiving IHV-001 14d after tumor challenge. Positive correlations were found between percentages of CD8+PD1+and CD4+TIM3+, and tumor burden in IOV-001-treated mice. On 14d, PD1+ expression in both CD4+ and CD8+ T cell subsets was significantly lower in surviving mice treated with IHV-001. Improved survival using this approach was also observed in the Pan02 orthotopic pancreatic model. Latest data will be presented. Conclusions: These data support the antitumor activity of this novel immunotherapeutic platform in multiple cancers beyond glioblastoma. Results suggest that efficacy is associated with a systemic immunological response, resulting in generation of Th1 antitumor cytotoxic T cells. Future studies are seeking to resolve the factors triggering good v. poor responses using phenotypic evaluation of T cell activation/exhaustion markers and Th1/Th2 cytokine production. Citation Format: Jenny Zilberberg, Amelia Zellander, Christopher Uhl, Christopher Cultrara, Kenneth kirby, Essam Elazaq, Charles B. Scott, David W. Andrews, Mark Exley. Personalized immunotherapeutic platform with evidence of clinical activity in glioblastoma (IGV-001) protects mice against other lethal solid tumor challenges [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 626.

Surgical and systemic therapies for addressing occult disease in advanced epithelial ovarian cancer

The incidence of peritoneal recurrence in advanced epithelial ovarian cancer (EOC) is high and could be attributed to the high prevalence of occult disease the persists despite complete cytoreductive surgery (CRS) and systemic chemotherapy. Several therapeutic approaches have been used to address such occult disease. Hyperthermic intraperitoneal chemotherapy (HIPEC) acts on microscopic disease as well as free intraperitoneal cancer cells shed during surgery, thus, reducing the risk of recurrence. Maintenance therapies like Poly ADP-Ribosyl Polymerase (PARP) inhibitors and the anti-angiogenic agent bevacizumab are used as maintenance therapies to delay recurrence. The most definitive way to eradicate such occult disease completely is resection of the peritoneum. The high preponderance of occult disease in the parietal peritoneum and some regions of the visceral peritoneum has led some surgeons to investigate the role of a total parietal peritonectomy (TPP) performed along with wide resection of the visceral peritoneum as a strategy for addressing occult disease. The mechanism of action differs from that of HIPEC and systemic therapies. It is possible that the benefit of each of these therapies is additive. EOC is a heterogeneous disease with a number of clinicopathological and molecular factors influencing the prognosis. There are likely to be different subgroups of patients that benefit from each of these 4 therapies or a combination of these. In this manuscript, we review the rationale and current evidence for the use of each of these therapies and discuss the potential role of a TPP in light of other therapies.

Plant Viral Nanoparticle Conjugated with Anti-PD-1 Peptide for Ovarian Cancer Immunotherapy.

Immunotherapy holds tremendous potential in cancer therapy, in particular, when treatment regimens are combined to achieve synergy between pathways along the cancer immunity cycle. In previous works, we demonstrated that in situ vaccination with the plant virus cowpea mosaic virus (CPMV) activates and recruits innate immune cells, therefore reprogramming the immunosuppressive tumor microenvironment toward an immune-activated state, leading to potent anti-tumor immunity in tumor mouse models and canine patients. CPMV therapy also increases the expression of checkpoint regulators on effector T cells in the tumor microenvironment, such as PD-1/PD-L1, and we demonstrated that combination with immune checkpoint therapy improves therapeutic outcomes further. In the present work, we tested the hypothesis that CPMV could be combined with anti-PD-1 peptides to replace expensive antibody therapies. Specifically, we set out to test whether a multivalent display of anti-PD-1 peptides (SNTSESF) would enhance efficacy over a combination of CPMV and soluble peptide. Efficacy of the approaches were tested using a syngeneic mouse model of intraperitoneal ovarian cancer. CPMV combination with anti-PD-1 peptides (SNTSESF) resulted in increased efficacy; however, increased potency against metastatic ovarian cancer was only observed when SNTSESF was conjugated to CPMV, and not added as a free peptide. This can be explained by the differences in the in vivo fates of the nanoparticle formulation vs. the free peptide; the larger nanoparticles are expected to exhibit prolonged tumor residence and favorable intratumoral distribution. Our study provides new design principles for plant virus-based in situ vaccination strategies.

Positron Emission Tomographic Imaging of Tumor Cell Death Using Zirconium-89-Labeled APOMAB\xae Following Cisplatin Chemotherapy in Lung and Ovarian Cancer Xenograft Models

PurposeEarly detection of tumor treatment responses represents an unmet clinical need with no approved noninvasive methods. DAB4, or its chimeric derivative, chDAB4 (APOMAB®) is an antibody that targets the Lupus associated antigen (La/SSB). La/SSB is over-expressed in malignancy and selectively targeted by chDAB4 in cancer cells dying from DNA-damaging treatment. Therefore, chDAB4 is a unique diagnostic tool that detects dead cancer cells and thus could distinguish between treatment responsive and nonresponsive patients.ProceduresIn clinically relevant tumor models, mice bearing subcutaneous xenografts of human ovarian or lung cancer cell lines or intraperitoneal ovarian cancer xenografts were untreated or given chemotherapy followed 24h later by chDAB4 radiolabeled with [89Zr]ZrIV. Tumor responses were monitored using bioluminescence imaging and caliper measurements. [89Zr]Zr-chDAB4 uptake in tumor and normal tissues was measured using an Albira SI Positron-Emission Tomography (PET) imager and its biodistribution was measured using a Hidex gamma-counter.ResultsTumor uptake of [89Zr]Zr-chDAB4 was detected in untreated mice, and uptake significantly increased in both human lung and ovarian tumors after chemotherapy, but not in normal tissues.ConclusionGiven that tumors, rather than normal tissues, were targeted after chemotherapy, these results support the clinical development of chDAB4 as a radiodiagnostic imaging agent and as a potential predictive marker of treatment response.

Ovarian cancer modulates the immunosuppressive function of CD11b+Gr1+ myeloid cells via glutamine metabolism

ObjectiveImmature CD11b + Gr1+ myeloid cells that acquire immunosuppressive capability, also known as myeloid-derived suppressor cells (MDSCs), are a heterogeneous population of cells that regulate immune responses. Our study's objective was to elucidate the role of ovarian cancer microenvironment in regulating the immunosuppressive function of CD11b+Gr1+ myeloid cells. MethodsAll studies were performed using the intraperitoneal ID8 syngeneic epithelial ovarian cancer mouse model. Myeloid cell depletion and immunotherapy were carried out using anti-Gr1 mAb, gemcitabine treatments, and/or anti-PD1 mAb. The treatment effect was assessed by a survival curve, in situ luciferase-guided imaging, and histopathologic evaluation. Adoptive transfer assays were carried out between congenic CD45.2 and CD45.1 mice. Immune surface and intracellular markers were assessed by flow cytometry. ELISA, western blot, and RT-PCR techniques were employed to assess the protein and RNA expression of various markers. Bone marrow-derived myeloid cells were used for ex-vivo studies. ResultsThe depletion of Gr1+ immunosuppressive myeloid cells alone and in combination with anti-PD1 immunotherapy inhibited ovarian cancer growth. In addition to the adoptive transfer studies, these findings validate the role of immunosuppressive CD11b+Gr1+ myeloid cells in promoting ovarian cancer. Mechanistic investigations showed that ID8 tumor cells and their microenvironments produced recruitment and regulatory factors for immunosuppressive CD11b+Gr1+ myeloid cells. CD11b+Gr1+ myeloid cells primed by ID8 tumors showed increased immunosuppressive marker expression and acquired an energetic metabolic phenotype promoted primarily by increased oxidative phosphorylation fueled by glutamine. Inhibiting the glutamine metabolic pathway reduced the increased oxidative phosphorylation and decreased immunosuppressive markers’ expression and function. Dihydrolipoamide succinyl transferase (DLST), a subunit of α-KGDC in the TCA cycle, was found to be the most significantly elevated gene in tumor-primed myeloid cells. The inhibition of DLST reduced oxidative phosphorylation, immunosuppressive marker expression and function in myeloid cells. ConclusionOur study shows that the ovarian cancer microenvironment can regulate the metabolism and function of immunosuppressive CD11b + Gr1+ myeloid cells and modulate its immune microenvironment. Targeting glutamine metabolism via DLST in immunosuppressive myeloid cells decreased their activity, leading to a reduction in the immunosuppressive tumor microenvironment. Thus, targeting glutamine metabolism has the potential to enhance the success of immunotherapy in ovarian cancer.