Intraoperative hyperthermic intraperitoneal chemotherapy after cytoreductive surgery for peritoneal carcinomatosis in an experimental model

An Organoid Model for the Therapeutic Effect of Hyperthermic Intraperitoneal Chemotherapy for Colorectal Cancer

BACKGROUND

Consensus regarding the hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal cancer (CRC) regimen remains elusive. In this study, patient-derived tumor organoids from CRC were utilized as a preclinical model for in vitro drug testing of HIPEC regimens commonly used in clinical practice. This approach was used to facilitate the clinical formulation of HIPEC.

METHOD

Tumor tissues and corresponding clinical data were obtained from patients diagnosed with CRC at the Sixth Affiliated Hospital of Sun Yat-Sen University. Qualified samples were cultured and passaged. We aimed to assess the sensitivity of in vitro hyperthermic perfusion using five different regimens, i.e. mitomycin C, mitomycin C combined with cisplatin, mitomycin C combined with 5-fluorouracil, oxaliplatin, and oxaliplatin combined with 5-fluorouracil.

RESULTS

Tumor organoids obtained from 46 patients with CRC were cultured, and in vitro hyperthermic perfusion experiments were conducted on 42 organoids using five different regimens. The average inhibition rate of mitomycin C was 85.2% (95% confidence interval [CI] 80.4-89.9%), mitomycin C combined with cisplatin was 85.5% (95% CI 80.2-90.7%), mitomycin C combined with 5-fluorouracil was 65.6% (95% CI 59.6-71.6%), oxaliplatin was 37.9% (95% CI 31.5-44.3%), and oxaliplatin combined with 5-fluorouracil was 40.7% (95% CI 33.9-47.5%).

CONCLUSION

In vitro hyperthermic perfusion demonstrates that the inhibition rate of mitomycin C, both alone and in combination with cisplatin, surpasses that of the combination of mitomycin C with 5-fluorouracil and oxaliplatin. In clinical practice, the combination of mitomycin C and cisplatin can be regarded as the optimal choice for HIPEC in CRC.

Effect of Intraperitoneal Chemotherapy with Regorafenib on IL-6 and TNF-α Levels and Peritoneal Cytology: Experimental Study in Rats with Colorectal Peritoneal Carcinomatosis

Cytoreductive surgery (CRS), combined with hyperthermic intraperitoneal chemotherapy, has significantly improved survival outcomes in patients with peritoneal carcinomatosis from colorectal cancer (CRC). Regorafenib is an oral agent administered in patients with refractory metastatic CRC. Our aim was to investigate the outcomes of intraperitoneal administration of regorafenib for intraperitoneal chemotherapy (IPEC) or/and CRS in a rat model of colorectal peritoneal metastases regarding immunology and peritoneal cytology. A total of 24 rats were included. Twenty-eight days after carcinogenesis induction, rats were randomized into following groups: group A: control group; group B: CRS only; group C: IPEC only; and group D: CRS + IPEC. On day 56 after carcinogenesis, euthanasia and laparotomy were performed. Serum levels of interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α) as well as peritoneal cytology were investigated. Groups B and D had statistically significant lower mean levels of IL-6 and TNF-α compared to groups A and C, but there was no significant difference between them. Both B and D groups presented a statistically significant difference regarding the rate of negative peritoneal cytology, when compared to the control group, but not to group C. In conclusion, regorafenib-based IPEC, combined with CRS, may constitute a promising tool against peritoneal carcinomatosis by altering the tumor microenvironment.

Treating colorectal peritoneal metastases with an injectable cytostatic loaded supramolecular hydrogel in a rodent animal model

Patients with peritoneal metastases (PM) of colorectal cancer have a very poor outcome. Intraperitoneal delivery of chemotherapy is the preferred route for PM treatment. The main limitation of the treatment options is the short residence time of the cytostatic, with subsequent short exposure of the cancer cells. To address this, a supramolecular hydrogel has been developed that allows both local and slow release of its encapsulated drug, mitomycin C (MMC) or cholesterol-conjugated MMC (cMMC), respectively. This experimental study investigates if drug delivery using this hydrogel improves the therapeutic efficacy against PM. PM was induced in WAG/Rij rats (n = 72) by intraperitoneally injecting syngeneic colon carcinoma cells (CC531) expressing luciferase. After seven days, animals received a single intraperitoneal injection with saline (n = 8), unloaded hydrogel (n = 12), free MMC (n = 13), free cMMC (n = 13), MMC-loaded hydrogel (n = 13), or cMMC-loaded hydrogel (n = 13). Primary outcome was overall survival with a maximum follow-up of 120 days. Intraperitoneal tumor development was non-invasive monitored via bioluminescence imaging. Sixty-one rats successfully underwent all study procedures and were included to assess therapeutic efficacy. After 120 days, the overall survival in the MMC-loaded hydrogel and free MMC group was 78% and 38%, respectively. A trend toward significance was found when comparing the survival curves of the MMC-loaded hydrogel and free MMC (p = 0.087). No survival benefit was found for the cMMC-loaded hydrogel compared to free cMMC. Treating PM with our MMC-loaded hydrogel, exhibiting prolonged MMC exposure, seems effective in improving survival compared to treatment with free MMC.

Hyperthermic Intraperitoneal Chemotherapy and Recirculation with CO2: A Safe Technique

Introduction: Hyperthermic IntraPEritoneal Chemotherapy (HIPEC) has evolved as a treatment for peritoneal carcinomatosis in various tumors after a careful and complete cytoreductive surgery, and it demonstrated much better and longer survival than more traditional therapeutic schemas. Our objective has been to examine the safety, efficacy and survival achieved with closed technique with CO₂-agitation system Combat PRS^® (Peritoneal Recirculation System: PRS). To achieve this, we compared the appearance of adverse events, mortality and survival with the described using classic techniques (open, closed without CO₂-agitation) for the treatment of selected patients with peritoneal carcinomatosis; Materials and methods: We studied overall survival, disease-free survival and safety (morbidity and mortality) of the administration of HIPEC through a closed method technique with CO₂ recirculation (Combat PRS^®) in 482 patients from 11 Spanish hospitals; Results: The mortality of our technique (1.66%) was similar to other published techniques (open, closed). Morbidity exhibited a 9.96% rate of Clavien-Dindo (CD) III/IV complications in 482 patients, which was lower than in other series. Survival (overall survival (OS) and disease-free survival (DFS)) was similar to previously published results: 86% 1y-OS, 54% 3y-OS, 77% 1y-DFS and 31% 3y-DFS; Conclusion: The procedure with closed PRS with CO₂ agitation is as safe as standard open and closed procedures for the administration of HIPEC after complete cytoreductive surgery, with similar and very low mortality (1.66%) and lower morbidity (9.96% CD III and IV in our series vs range of 20–40% in the majority of different series); only Kusamura had similar results, with 12% in 205 patients, using the closed technique without CO₂ agitation).

Generating patient-derived ascites-dependent xenograft mouse models of peritoneal carcinomatosis

Clinically relevant animal models are crucial for effective development of therapeutics for peritoneal carcinomatosis (PC). This protocol describes the generation of patient-derived ascites-dependent xenograft (PDADX) models from the cellular component of ascites. The use of routine intraperitoneal injection of the fluid component of ascites is analogous to the biological events occurring intra-abdominally in patients with PC. By serving as a proxy, PDADX models represent a valuable tool for preclinical testing of new therapeutics for PC.

For complete details on the use and execution of this protocol, please refer to Hendrikson et al. (2022).

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Generation of patient-derived ascites-dependent xenograft (PDADX) models

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Serial passages of PDADX tumors in mice

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Evaluation of patient-specific drug efficacy utilizing PDADX models

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Inhibition of LPS-mediated TLR4 activation abrogates gastric adenocarcinoma-associated peritoneal metastasis

Surgical resection, the cornerstone of curative intent treatment for gastric adenocarcinoma, is associated with a high rate of infection-related post-operative complications, leading to an increased incidence of metastasis to the peritoneum. However, the mechanisms underlying this process are poorly understood. Lipopolysaccharide (LPS), an antigen from Gram-negative bacteria, represents a potential mechanism via induction of local and systemic inflammation through activation of Toll-like receptor (TLR). Here, we use both a novel ex vivo model of peritoneal metastasis and in vivo animal models to assess gastric cancer cell adhesion to peritoneum both before and after inhibition of the TLR4 pathway. We demonstrate that activation of TLR4 by either LPS or Gram-negative bacteria (E. coli) significantly increases the adherence of gastric cancer cells to human peritoneal mesothelial cells, and that this increased adherence is abrogated by inhibition of the TLR4 signal cascade and downstream TAK1 and MEK1/2 pathways. We also demonstrate that the influence of LPS on adherence extends to peritoneal tissue and metastatic spread. Furthermore, we show that loss of TLR4 at the site of metastasis reduces tumor cell adhesion, implicating the TLR4 signaling cascade in potentiating metastatic adhesion and peritoneal spread. These results identify potential therapeutic targets for the clinical management of patients undergoing resection for gastric cancer.

Magnetic Compression of Tumor Spheroids Increases Cell Proliferation In Vitro and Cancer Progression In Vivo

A growing tumor is submitted to ever-evolving mechanical stress. Endoscopic procedures add additional constraints. However, the impact of mechanical forces on cancer progression is still debated. Herein, a set of magnetic methods is proposed to form tumor spheroids and to subject them to remote deformation, mimicking stent-imposed compression. Upon application of a permanent magnet, the magnetic tumor spheroids (formed from colon cancer cells or from glioblastoma cells) are compressed by 50% of their initial diameters. Such significant deformation triggers an increase in the spheroid proliferation for both cell lines, correlated with an increase in the number of proliferating cells toward its center and associated with an overexpression of the matrix metalloproteinase-9 (MMP-9). In vivo peritoneal injection of the spheroids made from colon cancer cells confirmed the increased aggressiveness of the compressed spheroids, with almost a doubling of the peritoneal cancer index (PCI), as compared with non-stimulated spheroids. Moreover, liver metastasis of labeled cells was observed only in animals grafted with stimulated spheroids. Altogether, these results demonstrate that a large compression of tumor spheroids enhances cancer proliferation and metastatic process and could have implications in clinical procedures where tumor compression plays a role.

Establishment of an Experimental System for Intraperitoneal Chemotherapy in a Rat Model

AIM

To establish an experimental system for comparing different methods of intraperitoneal chemotherapy in a rat model.

MATERIALS AND METHODS

We used six-week-old Sprague-Dawley rats, and created an early postoperative intraperitoneal chemotherapy (EPIC) system using 18-gauge syringes and evacuators, and a hyperthermic intraperitoneal chemotherapy (HIPEC) system using two peristaltic pumps which controlled the flow rate and temperature. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) was achieved using a nozzle for dispersing aerosols at a flow rate up to 41.5 ml/min. The distribution and intensity of 0.2% trypan blue dye was compared among three methods.

RESULTS

The distribution was limited and the intensity was weak after EPIC, and the dye stained moderately in gravity-dependent regions after HIPEC. On the other hand, the distribution was the most comprehensive, and the intensity was the greatest after PIPAC.

CONCLUSION

This experimental system in a rat model may reflect the comparative effect among EPIC, HIPEC and PIPAC in humans.

Preclinical In Vivo-Models to Investigate HIPEC; Current Methodologies and Challenges

Simple Summary

Efficacy of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) depends on patient selection, tumor type, delivery technique, and treatment parameters such as temperature, carrier solution, type of drug, dosage, volume, and treatment duration. Preclinical research offers a powerful tool to investigate the impact of these parameters and to assists in designing potentially more effective treatment protocols and clinical trials. This study aims to review the objectives, methods, and clinical relevance of in vivo preclinical HIPEC studies found in the literature. In total, 60 articles were included in this study. The selected articles were screened on the HIPEC parameters. Recommendations are provided and possible pitfalls are discussed on the choice of type of animal and tumor model per stratified parameters and study goal. The guidelines presented in this paper can improve the clinical relevance and impact of future in vivo HIPEC experiments.

Abstract

Hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment modality for patients with peritoneal metastasis (PM) of various origins which aims for cure in combination with cytoreductive surgery (CRS). Efficacy of CRS-HIPEC depends on patient selection, tumor type, delivery technique, and treatment parameters such as temperature, carrier solution, type of drug, dosage, volume, and treatment duration. Preclinical research offers a powerful tool to investigate the impact of these parameters and to assist in designing potentially more effective treatment protocols and clinical trials. The different methodologies for peritoneal disease and HIPEC are variable. This study aims to review the objectives, methods, and clinical relevance of in vivo preclinical HIPEC studies found in the literature. In this review, recommendations are provided and possible pitfalls are discussed on the choice of type of animal and tumor model per stratified parameters and study goal. The guidelines presented in this paper can improve the clinical relevance and impact of future in vivo HIPEC experiments.

Injured tissues favor cancer cell implantation via fibrin deposits on scar zones

AIM

Evaluation of fibrin role on cancer cells implantation in injured tissues and studying the molecular mechanism of cancer cell interaction with the peritoneal damage.

MATERIAL AND METHODS

Mouse colon cancer (CT26) and human mesothelial cells (HMCs) were used. CT26 cells were implanted on injured peritoneal zones. Icodextrin was used as a lubricant. For in vitro studies, fibrin clots from human plasma were used. The cell-fibrin interaction was observed by optical, electronic, and confocal microscopies. Aprotinin was used as a plasmin inhibitor. Hemostasis impact quantified by (1) the fibrin degradation product D-Dimer and PAR expression in HMCs; (2) the expression of plasminogen activator (PA) and its inhibitor (PAI-1) in cancer cells by qPCR and in supernatants through ELISA after in vitro HMC incubation with 2U of thrombin for 24 h.

RESULTS

(i) Cancer cell lines were adhered and implanted into the wound area in vivo in both the incision and peeling zones of the peritoneum and on the fibrin network in vitro. (ii) Icodextrin significantly inhibited cancer nodule formation in the scar and the incision or peritoneal damaged zones after surgery. (iii) In in vitro studies, cancer cell interaction with the fibrin clot generated a lysed area, causing an increase in plasmin-dependent fibrinolysis measured by D-dimer levels in the supernatants that was inhibited by aprotinin. (iv) Aprotinin inhibited cell-fibrin interaction and invasion. (v) Thrombin upregulates PAI-1 and downregulates PA expression in HMC.

CONCLUSION

Injured tissues favor cancer cell implantation through generated fibrin. Fibrin-cancer cells adhesion can be inhibited by icodextrin.

Preclinical evaluation of local prolonged release of paclitaxel from gelatin microspheres for the prevention of recurrence of peritoneal carcinomatosis in advanced ovarian cancer

Patients with advanced ovarian cancer develop recurrence despite initial treatment response to standard treatment of surgery and intravenous/intraperitoneal (IP) chemotherapy, partly due to a limited peritoneal exposure time of chemotherapeutics. Paclitaxel-loaded genipin-crosslinked gelatin microspheres (PTX-GP-MS) are evaluated for the treatment of microscopic peritoneal carcinomatosis and prevention of recurrent disease. The highest drug load (39.2 µg PTX/mg MS) was obtained by immersion of GP-MS in aqueous PTX nanosuspension (PTXnano-GP-MS) instead of ethanolic PTX solution (PTXEtOH-GP-MS). PTX release from PTX-GP-MS was prolonged. PTXnano-GP-MS displayed a more controlled release compared to a biphasic release from PTXEtOH-GP-MS. Anticancer efficacy of IP PTX-GP-MS (PTXEtOH-GP-MS, D = 7.5 mg PTX/kg; PTXnano-GP-MS D = 7.5 and 35 mg PTX/kg), IP nanoparticular albumin-bound PTX (D = 35 mg PTX/kg) and controls (0.9% NaCl, blank GP-MS) was evaluated in a microscopic peritoneal carcinomatosis xenograft mouse model. PTXnano-GP-MS showed superior anticancer efficacy with significant increased survival time, decreased peritoneal carcinomatosis index score and ascites incidence. However, prolonged PTX release over 14 days from PTXnano-GP-MS caused drug-related toxicity in 27% of high-dosed PTXnano-GP-MS-treated mice. Dose simulations for PTXnano-GP-MS demonstrated an optimal survival without drug-induced toxicity in a range of 7.5-15 mg PTX/kg. Low-dosed PTXnano-GP-MS can be a promising IP drug delivery system to prevent recurrent ovarian cancer.

Intraperitoneal mitomycin C improves survival compared to cytoreductive surgery alone in an experimental model of high-grade pseudomyxoma peritonei

Pseudomyxoma peritonei (PMP) is a rare cancer commonly originating from appendiceal neoplasms that presents with mucinous tumor spread in the peritoneal cavity. Patients with PMP are treated with curative intent by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The value of adding HIPEC to CRS has not been proven in randomized trials, and the objective of this study was to investigate the efficacy of intraperitoneal mitomycin C (MMC) and regional hyperthermia as components of this complex treatment. Xenograft tissue established from a patient with histologically high-grade PMP with signet ring cell differentiation was implanted intraperitoneally in 65 athymic nude male rats and the animals were stratified into three treatment groups; the cytoreductive surgery group (CRSG, CRS only), the normothermic group (NG, CRS and intraperitoneal chemotherapy perfusion (IPEC) with MMC at 35 ºC), and the hyperthermic group (HG, CRS and IPEC at 41 ºC). The main endpoints were survival and tumor weight at autopsy. Adequate imitation of the clinical setting and treatment approach was achieved. The median survival was 31 days in the CRSG, 60 days in NG and 67 days in HG. The median tumor weights at autopsy were 34 g in CRSG, 23 g NG and 20 g in HG. In conclusion, the addition of IPEC with MMC after CRS doubled the survival time and reduced tumor growth compared to CRS alone. Adding regional hyperthermia resulted in a modest improvement of treatment outcome.

Pretargeted radioimmunotherapy and SPECT imaging of peritoneal carcinomatosis using bioorthogonal click chemistry: probe selection and first proof-of-concept

Rationale: Pretargeted radioimmunotherapy (PRIT) based upon bioorthogonal click chemistry has been investigated for the first time in the context of peritoneal carcinomatosis using a CEA-targeting 35A7 mAb bearing trans-cyclooctene (TCO) moieties and several ¹⁷⁷Lu-labeled tetrazine (Tz) radioligands. Starting from three Tz probes containing PEG linkers of varying lengths between the DOTA and Tz groups (i.e. PEG_n = 3, 7, or 11, respectively, for Tz-1, Tz-2, and Tz-3), we selected [¹⁷⁷Lu]Lu-Tz-2 as the most appropriate for pretargeted SPECT imaging and demonstrated its efficacy in tumor growth control. Methods: An orthotopic model of peritoneal carcinomatosis (PC) was obtained following the intraperitoneal (i.p.) injection of A431-CEA-Luc cells in nude mice. Tumor growth was assessed using bioluminescence imaging. Anti-CEA 35A7 mAb was grafted with 2-3 TCO per immunoglobulin. Pretargeted SPECT imaging and biodistribution experiments were performed to quantify the activity concentrations of [¹⁷⁷Lu]Lu-Tz-1-3 in tumors and non-target organs to determine the optimal Tz probe for the PRIT of PC. Results: The pharmacokinetic profiles of [¹⁷⁷Lu]Lu-Tz-1-3 alone were determined using both SPECT imaging and biodistribution experiments. These data revealed that [¹⁷⁷Lu]Lu-Tz-1 was cleared via both the renal and hepatic systems, while [¹⁷⁷Lu]Lu-Tz-2 and [¹⁷⁷Lu]Lu-Tz-3 were predominantly excreted via the renal system. In addition, these results illuminated that the longer the PEG linker, the more rapidly the Tz radioligand was cleared from the peritoneal cavity. The absorbed radiation dose corresponding to pretargeting with 35A7-TCO followed 24 h later by [¹⁷⁷Lu]Lu-Tz-1-4 was higher for tumors following the administration of [¹⁷⁷Lu]Lu-Tz-2 (i.e. 0.59 Gy/MBq) compared to either [¹⁷⁷Lu]Lu-Tz-1 (i.e. 0.25 Gy/MBq) and [¹⁷⁷Lu]Lu-Tz-3 (i.e. 0.18 Gy/MBq). In a longitudinal PRIT study, we showed that the i.p. injection of 40 MBq of [¹⁷⁷Lu]Lu-Tz-2 24 hours after the systemic administration of 35A7-TCO significantly slowed tumor growth compared to control mice receiving only saline or 40 MBq of [¹⁷⁷Lu]Lu-Tz-2 alone. Ex vivo measurement of the peritoneal carcinomatosis index (PCI) confirmed that PRIT significantly reduced tumor growth (PCI = 15.5 ± 2.3 after PRIT vs 30.0 ± 2.3 and 30.8 ± 1.4 for the NaCl and [¹⁷⁷Lu]Lu-Tz-2 alone groups, respectively). Conclusion: Our results clearly demonstrate the impact of the length of PEG linkers upon the biodistribution profiles of ¹⁷⁷Lu-labeled Tz radioligands. Furthermore, we demonstrated for the first time the possibility of using bioorthogonal chemistry for both the pretargeted SPECT and PRIT of peritoneal carcinomatosis.

Comparison of implantation sites for the development of peritoneal metastasis in a colorectal cancer mouse model using non-invasive bioluminescence imaging

The development of cancer mouse models is still needed for the identification and preclinical validation of novel therapeutic targets in colorectal cancer, which is the third leading cause of cancer-related deaths in Europe. The purpose of this study was to determine the most accurate tumour cell injection method to obtain suitable peritoneal metastasis (PM) for subsequent therapeutic treatments. Here, we grafted murine colon carcinoma CT-26 cells expressing luciferase into immunocompetent BALB-c mice by intravenous injection (IV group), subcutaneous injection (SC group), intraperitoneal injection after peritoneal scratching (A group) or intraperitoneal injection alone (IP group). Tumour growth was monitored by bioluminescence during the first 15 days post-grafting. The peritoneal carcinomatosis index was evaluated macroscopically, histology, immunohistochemistry and multiphoton microscopy were performed in peritoneal tumour tissue. Upon implantation, no tumour growth was observed in the IV group, similar to the non-injected group. Both the IP and SC groups showed intermediate growth rates, but the SC group produced only a single subcutaneous nodule. The A group exhibited the highest tumour growth at 15 days post-surgery. Anatomic and histologic analyses corroborated the existence of various tumour nodules, and multiphoton microscopy was used to evaluate tumour fibrosis-infiltrating cells in a non-pathologic peritoneum. In conclusion, limited PM was obtained by IP injection, whereas IP injection after peritoneal scratching led to an extensive PM murine model for evaluating new therapeutics.

Body surface area-based versus concentration-based intraperitoneal perioperative chemotherapy in a rat model of colorectal peritoneal surface malignancy: pharmacologic guidance towards standardization

Worldwide, cytoreductive surgery (CRS) and hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) are used in current clinical practice for colorectal peritoneal surface malignancy (PSM) treatment. Although, there is an acknowledged standardization regarding the CRS, we are still lacking a much-needed standardization amongst the various intraperitoneal (IP) chemotherapy protocols, including the HIPEC dosing regimen. We should rely on pharmacologic evidence building towards such a standardization. The current IP chemotherapy dosing regimens can be divided into body surface area (BSA)-based and concentration-based protocols. A preclinical animal study was designed to evaluate pharmacologic advantage (PA), efficacy and survival. WAG/Rij rats were IP injected with the rat colonic carcinoma cell line CC-531. Animals were randomized into three groups: CRS alone or CRS combined with oxaliplatin-based HIPEC (either BSA- or concentration-based). There was no difference in PA between the two groups (p=0.283). Platinum concentration in the tumor nodule was significantly higher in the concentration-based group (p<0.001). Median survival did not differ between the treatment groups (p<0.250). This preclinical study, in contrast to previous thinking, clearly demonstrates that the PA does not provide any information about the true efficacy of the drug and emphasizes the importance of the tumor nodule as pharmacologic endpoint.

Antibody PEGylation in bioorthogonal pretargeting with trans-cyclooctene/tetrazine cycloaddition: in vitro and in vivo evaluation in colorectal cancer models

Bioorthogonal chemistry represents a challenging approach in pretargeted radioimmunotherapy (PRIT). We focus here on mAb modifications by grafting an increase amount of trans-cyclooctene (TCO) derivatives (0 to 30 equivalents with respect to mAb) bearing different polyethylene glycol (PEG) linkers between mAb and TCO (i.e. PEG₀ (1), PEG₄ (2) and PEG₁₂ (3)) and assessing their functionality. We used colorectal xenograft (HT29/Ts29.2) and peritoneal carcinomatosis (A431-CEA-Luc/35A7) as tumor cells/mAbs models and fluorescent tetrazines (TZ). MALDI-TOF MS shows that grafting with 2,3 increases significantly the number of TCO per mAb compared with no PEG. In vitro immunofluorescence showed that Ts29.2 and 35A7 labeling intensity is correlated with the number of TCO when using 1,3 while signals reach a maximum at 10 equivalents when using 2. Under 10 equivalents conditions, the capacity of resulting mAbs-1–3 for antigen recognition is similar when reported per grafted TCO and comparable to mAbs without TCO. In vivo, on both models, pretargeting with mAbs-2,3 followed by TZ injection induced a fluorescent signal two times lower than with mAbs-1. These findings suggest that while PEG linkers allow a better accessibility for TCO grafting, it might decrease the number of reactive TCO. In conclusion, mAb-1 represents the best candidate for PRIT.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for peritoneal metastases of colorectal origin

Weak evidence base for clinical trials

Pretreatment with VEGF(R)-inhibitors reduces interstitial fluid pressure, increases intraperitoneal chemotherapy drug penetration, and impedes tumor growth in a mouse colorectal carcinomatosis model

Cytoreductive surgery combined with intraperitoneal chemotherapy (IPC) is currently the standard treatment for selected patients with peritoneal carcinomatosis of colorectal cancer. However, especially after incomplete cytoreduction, disease progression is common and this is likely due to limited tissue penetration and efficacy of intraperitoneal cytotoxic drugs. Tumor microenvironment-targeting drugs, such as VEGF(R) and PDGFR inhibitors, can lower the heightened interstitial fluid pressure in tumors, a barrier to drug delivery. Here, we investigated whether tumor microenvironment-targeting drugs enhance the effectiveness of intraperitoneal chemotherapy. A mouse xenograft model with two large peritoneal implants of colorectal cancer cells was developed to study drug distribution and tumor physiology during intraperitoneal Oxaliplatin perfusion. Mice were treated for six days with either Placebo, Imatinib (anti-PDGFR, daily), Bevacizumab (anti-VEGF, twice) or Pazopanib (anti-PDGFR, -VEGFR; daily) followed by intraperitoneal oxaliplatin chemotherapy. Bevacizumab and Pazopanib significantly lowered interstitial fluid pressure, increased Oxaliplatin penetration (assessed by laser ablation inductively coupled plasma mass spectrometry) and delayed tumor growth of peritoneal implants (assessed by MRI). Our findings suggest that VEGF(R)-inhibition may improve the efficacy of IPC, particularly for patients for whom a complete cytoreduction might not be feasible.

Animal models of colorectal peritoneal metastasis

Colorectal cancer remains an important cause of mortality worldwide. The presence of peritoneal carcinomatosis (PC) causes significant symptoms and is notoriously difficult to treat. Therefore, informative preclinical research into the mechanisms and possible novel treatment options of colorectal PC is essential in order to improve the prognostic outlook in these patients. Several syngeneic and xenograft animal models of colorectal PC were established, studying a wide range of experimental procedures and substances. Regrettably, more sophisticated models such as those giving rise to spontaneous PC or involving genetically engineered mice are lacking. Here, we provide an overview of all reported colorectal PC animal models and briefly discuss their use, strengths, and limitations.

Therapeutic Efficacy of Alpha-RIT Using a (213)Bi-Anti-hCD138 Antibody in a Mouse Model of Ovarian Peritoneal Carcinomatosis

Purpose

Ovarian peritoneal carcinomatosis is a pathology for which effective cures are currently lacking. New research protocols seek to eradicate residual micrometastases following cytoreductive surgery by using hyperthermic intraperitoneal chemotherapy (HIPEC) or radioimmunotherapy (RIT). This study aims to first develop alpha-RIT using an anti-CD138 mAb radiolabeled with an alpha-emitter, bismuth-213 (²¹³Bi-B-B4) and HIPEC in a nude mouse model and second to compare and combine these techniques.

Material and methods

A murine model of postoperative ovarian peritoneal carcinomatosis was established. A pilot group of six mice received an intraperitoneal injection of luciferase-tagged SHIN-3 cells and bioluminescence was measured every day. Cytoreductive surgery was performed at day 14 (n = 4) and 29 (n = 2). Because the residual bioluminescence signal measured after surgery was equivalent to that obtained 3 days after the graft, HIPEC or alpha-RIT treatments were applied 3 days after the graft. Ten mice were treated by HIPEC with cisplatine (37.5 mg/mL), 11 with 7.4 MBq of ²¹³Bi-B-B4, seven with 11.1 MBq of ²¹³Bi-B-B4, and 10 mice were treated with the combined therapy (HIPEC + 7.4 MBq of ²¹³Bi-B-B4). Eleven mice received no treatment. Bioluminescence imaging and survival were assessed.

Results

Alpha-RIT 7.4 MBq and 11.1 MBq significantly improved survival (p = 0.0303 and p = 0.0070, respectively), whereas HIPEC and HIPEC + alpha-RIT treatments did not significantly ameliorate survival as compared to the control group.

Conclusion

Survival was significantly increased by alpha-RIT treatment in mice with peritoneal carcinomatosis of ovarian origin; however, HIPEC alone or in combination with alpha-RIT had no significant effect.

Hyperthermic intra-peritoneal chemotherapy and anticancer immune response

Peritoneal carcinomatosis (PC) is a metastatic disease of primary tumors localized in the abdomen. Although this disease is considered a terminal condition, recent treatments combining surgery with heated intra-peritoneal chemotherapy (HIPEC) significantly increase patient survival. We have determined that the protective effect of HIPEC is partially linked to the induction of an efficient anticancer immune response.

Hyperthermic intraperitoneal chemotherapy leads to an anticancer immune response via exposure of cell surface heat shock protein 90

The occurrence of peritoneal carcinomatosis is a major cause of treatment failure in colorectal cancer and is considered incurable. However, new therapeutic approaches have been proposed, including cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC). Although HIPEC has been effective in selected patients, it is not known how HIPEC prolongs a patient's lifespan. Here, we have demonstrated that HIPEC-treated tumor cells induce the activation of tumor-specific T cells and lead to vaccination against tumor cells in mice. We have established that this effect results from the HIPEC-mediated exposure of heat shock protein (HSP) 90 at the plasma membrane. Inhibition or blocking of HSP90, but not HSP70, prevented the HIPEC-mediated antitumoral vaccination. Our work raises the possibility that the HIPEC procedure not only kills tumor cells but also induces an efficient anticancer immune response, therefore opening new opportunities for cancer treatment.

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy improves survival of patients with peritoneal carcinomatosis from colorectal cancer: a case-control study from a Chinese center

Background

Advanced colorectal cancer (CRC) is prone to developing peritoneal carcinomatosis (PC). This case-control study was to compare the efficacy and safety of cytoreductive surgery (CRS) versus CRS plus hyperthermic intraperitoneal chemotherapy (HIPEC) in Chinese patients with CRC PC.

Methods

The 62 consecutive PC patients were treated with CRS (Control group, n = 29) or CRS + HIPEC (Study group, n = 33). The primary end point was overall survival (OS), the secondary end points were perioperative safety profiles.

Results

For the comparison of Control versus Study groups, the peritoneal cancer index (PCI) ≤20 was 13 (44.8%) versus 16 (48.5%) patients (P = 0.78), complete cytoreduction (CC0-1) was achieved in 9 (31.0%) versus 14 (42.4%) cases (P = 0.36). At the median OS was 8.5 (95% confidence interval [CI] 4.7–12.4) versus 13.7 (95% CI 10.0–16.5) months (P = 0.02), the 1-, 2-, and 3-year survival rates were 27.5% versus 63.6%, 12.0% versus 20.0%, and 0.0% versus 16.0%, respectively. Serious adverse events in postoperative 30 days were 9.4% versus 28.6% (P = 0.11). Multivariate analysis revealed that CRS + HIPEC, CC0-1, adjuvant chemotherapy ≥6 cycles were independent factors for OS benefit.

Conclusion

CRS + HIPEC could improve OS for CRC PC patients, with acceptable perioperative safety. J. Surg. Oncol 2014; 109:730–739.

Treatment of surgically resectable colorectal peritoneal metastases

Need for centres and training standards

Intraperitoneal chemotherapy (IPC) for peritoneal carcinomatosis: review of animal models

The development of suitable animal models is essential to experimental research on intraperitoneal chemotherapy (IPC). This review of the English literature (MEDLINE) presents a detailed analysis of current animal models and gives recommendations for future experimental research. Special consideration should be given to cytotoxic drug dose and concentration, tumor models, and outcome parameters.

Peritoneal metastases from colorectal cancer: patient selection for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Cytoreductive surgery (CRS) in combination with hyperthermic intraperitoneal chemotherapy (HIPEC) is an established treatment modality for patients with pseudomyxoma peritonei. The majority of patients with pseudomyxoma who have complete tumour removal and HIPEC are cured. Over the last decade CRS for peritoneal metastasis of colorectal origin has emerged as an effective treatment strategy in carefully selected patients. Although convincing evidence is limited, available data shows promising results. The key to a successful outcome is appropriate selection of patients. In patients with extensive peritoneal disease, where complete cytoreduction is not achieved, surgical treatment may not be beneficial and might impair quality of life. In this paper we discuss the challenges of selecting patients with colorectal peritoneal metastases who are likely to benefit from CRS with HIPEC.

Effect of alginate-chitosan sustained release microcapsules for transhepatic arterial embolization in VX2 rabbit liver cancer model

Two lipid-solid dispersion loading Norcantharidin sustained-released microspheres of alginate-chitosan (NCTD/LSD-ACMs) were prepared via the emulsification-gelation method. The effects of microspheres for transarterial hepatic chemoembolization were evaluated in VX2 rabbit liver cancer model. The VX2 animal model was established by biopsy needle, divided randomly into four groups, and disposed with three preparations including NCTD/LSD-ACMs (60-120 μm), NCTD/LSD-ACMs(120-200 μm), and NCTD solution through the hepatic arteries compared with the untreated group (control group). The serum of all rabbits before and at 3, 7, and 14 days after embolization was collected to determine the level of aspartate aminotransferase (AST). The AST level increased in the three treated groups on the first day compared with the control group (p < 0.05), and was higher in the two embolization groups (with no significant difference, p >0.05) than that in the NCTD group (p < 0.05). The tumor growth rates, which were significantly decreased in the two embolization groups compared with that in the control group, and the degree of liver cell necrosis assessed by the histopathological specimens, were used to evaluate the embolization effect. Liquefactive necrosis and coagulative necrosis were observed in the two embolization groups. The results showed that NCTD/LSD-ACMs are a potential candidate for embolization of liver cancer.

Outcome of surgery for colorectal cancer in the presence of peritoneal carcinomatosis

AIM

The detection of peritoneal carcinomatosis (PC) in colorectal cancer patients frequently results in a dilemma with regard to the optimal treatment strategy, especially when PC is encountered unexpectedly during surgery. The aim of this study was to evaluate outcomes of patients undergoing surgery for colorectal carcinoma in the presence of synchronous PC.

METHODS

Patients diagnosed with primary colorectal cancer and synchronous PC in three community hospitals were selected from the Eindhoven Cancer Registry database. Outcomes of postoperative complications, in-hospital mortality and overall survival were collected and analyzed according to the type of intervention performed.

RESULTS

Between 1995 and 2009, 169 colorectal cancer patients were diagnosed with synchronous PC, most of them unexpectedly during surgery (n = 130). 142 patients underwent surgery: primary tumor resection (n = 91), palliative procedure (n = 46) or exploration only (n = 5). In-hospital mortality was 41% after palliative surgery and 14% after primary tumor resection. Median survival was 12 weeks after palliative surgery or exploration as opposed to 55 weeks after primary tumor resection.

CONCLUSION

PC is most often encountered unexpectedly during surgery for colorectal cancer. Results of palliative procedures are very poor with a high in-hospital mortality rate and short survival. Resection of the primary tumor can be performed safely with relatively good outcomes but some patients could have benefited from an even more radical approach when the presence of PC would have been diagnosed at an earlier stage. Improvement of imaging techniques to detect PC prior to surgery is therefore urgently needed. Until this is the case, a high index of suspicion is required when subtle signs of PC are encountered.

Hyperthermic intraperitoneal chemotherapy in patients with peritoneal carcinomatosis: role of heat shock proteins and dissecting effects of hyperthermia

BACKGROUND

In patients with isolated peritoneal carcinomatosis (PC) of gastrointestinal cancer, hyperthermic intraperitoneal chemotherapy (HIPEC) represents a promising treatment option integrated into multimodal concepts. Heat shock proteins (HSP) seem to play a major role in cellular stress during HIPEC therapy. We analyzed differentially hyperthermic conditions and HSPs responsible for cell stress-mediated repair mechanisms in tumor tissues from patients who underwent HIPEC therapy and in an in vitro hyperthermic model.

METHODS

Tumor tissues from our patient cohort with isolated PC were selected for further analysis when representative material was available before and after HIPEC therapy. To further dissect the role of HSPs under conditions of hyperthermia, gene and protein expression was additionally determined, together with cellular apoptosis and proliferation in human HT-29 colon cancer cells.

RESULTS

Differently up-regulated HSP70/72 and HSP90 gene and protein expression was found in all investigated patient tumors. In vitro studies confirmed observations from clinical tumor analysis as underlying HSP-mediated cell stress mechanisms. Moreover, results from proliferation and apoptosis assays combined with differentiated HSP expression analysis demonstrated the relevance of preselecting specific target temperatures to achieve optimal toxic effects on remaining tumor cells in vivo.

CONCLUSIONS

Therapeutic approaches like HIPEC to achieve antiproliferative and apoptosis-inducing cellular effects in patients with PC are negatively influenced by highly conserved HSP mechanisms in tumor cells. This study shows for the first time that specific hyperthermic conditions are necessary to be established to achieve optimal toxic effects on tumor cells during HIPEC therapy, a finding that opens potentially new therapeutic strategies.

Peritoneal carcinomatosis of colorectal origin: Incidence, prognosis and treatment options

Peritoneal carcinomatosis (PC) is one manifestation of metastatic colorectal cancer (CRC). Tumor growth on intestinal surfaces and associated fluid accumulation eventually result in bowel obstruction and incapacitating levels of ascites, which profoundly affect the quality of life for affected patients. PC appears resistant to traditional 5-fluorouracil-based chemotherapy, and surgery was formerly reserved for palliative purposes only. In the absence of effective treatment, the historical prognosis for these patients was extremely poor, with an invariably fatal outcome. These poor outcomes likely explain why PC secondary to CRC has received little attention from oncologic researchers. Thus, data are lacking regarding incidence, clinical disease course, and accurate treatment evaluation for patients with PC. Recently, population-based studies have revealed that PC occurs relatively frequently among patients with CRC. Risk factors for developing PC have been identified: right-sided tumor, advanced T-stage, advanced N-stage, poor differentiation grade, and younger age at diagnosis. During the past decade, both chemotherapeutical and surgical treatments have achieved promising results in these patients. A chance for long-term survival or even cure may now be offered to selected patients by combining radical surgical resection with intraperitoneal instillation of heated chemotherapy. This combined procedure has become known as hyperthermic intraperitoneal chemotherapy. This editorial outlines recent advancements in the medical and surgical treatment of PC and reviews the most recent information on incidence and prognosis of this disease. Given recent progress, treatment should now be considered in every patient presenting with PC.

Hyperthermia and intraperitoneal chemotherapy for the treatment of peritoneal carcinomatosis: an experimental study

OBJECTIVE

Hyperthermic intraperitoneal chemotherapy (HIPEC) with mitomycin C can improve survival if used as an adjunct to cytoreductive surgery (CS) for treatment of peritoneal carcinomatosis (PC). It remains unclear if both hyperthermia and chemotherapy are essential for the reported survival benefit.

METHODS

Eighty WAG/Rij rats were inoculated intraperitoneally with the rat colon carcinoma cell line CC-531. Animals were randomly assigned to 1 of the 4 treatment groups (n = 20): CS only, CS followed by HIPEC (mitomycin 35 mg/m(2) at 41°C), CS followed by intraperitoneal mitomycin perfusion at 37°C, CS followed by intraperitoneal saline perfusion at 41°C. Survival was the primary outcome with a maximum follow up of 126 days.

RESULTS

Median survival was 62 days in rats treated with CS only and 57 days in rats treated with CS followed by hyperthermic saline perfusion. Rats receiving HIPEC had a median survival of 121 days (P = 0.022 when compared with CS only). In the group treated with chemotherapy at 37°C, 13 of 20 animals were still alive at the end of the experiment so median survival was not reached. (CS vs. IPEC: P = 0.002, hazard ratio 0.36, 95% CI 0.19-0.69) Rats treated with hyperthermic saline perfusion did not have an increased survival as compared with CS only.

CONCLUSIONS

The effectiveness of intraoperative intraperitoneal perfusion after CS is highly dependent on the presence of chemotherapeutic agents in the perfusate but not on hyperthermia. The need to include hyperthermia in the adjuvant intraoperative treatment after CS for PC should be further investigated.

Intraoperative versus early postoperative intraperitoneal chemotherapy after cytoreduction for colorectal peritoneal carcinomatosis: an experimental study

BACKGROUND

Perioperative intraperitoneal chemotherapy is used as an adjunct to cytoreductive surgery (CS) for peritoneal carcinomatosis (PC) in order to prolong survival. Worldwide, hyperthermic intraperitoneal chemotherapy (HIPEC), early postoperative intraperitoneal chemotherapy (EPIC), and combinations of the two are used. It remains unclear which regimen is most beneficial.

METHODS

The rat colon carcinoma cell line CC-531 was injected into the peritoneal cavity of 80 WAG/Rij rats to induce PC. Animals were randomized into four treatment groups (n = 20): CS only, CS followed by HIPEC (mitomycin 35 mg/m(2) at 41.5°C), CS followed by EPIC during 5 days (i.p. injection of mitomycin on day 1 and 5-fluorouracil on days 2-5), and CS followed by HIPEC plus EPIC. Primary outcome was survival.

RESULTS

In rats treated with CS only, median survival was 53 days (95% confidence interval (CI) 49-57 days). In rats treated with CS followed by HIPEC, survival was significantly (P = 0.001) increased (median survival 94 days, 95% CI 51-137 days). In the group treated with EPIC after CS, 12 out of 20 rats were still alive at the end of the experiment (P < 0.001 as compared with CS only). In the group receiving both treatments, 11 rats died of toxicity, and therefore this group was not included in the survival analysis.

CONCLUSIONS

Both EPIC and HIPEC were effective in prolonging survival. The beneficial effect of EPIC on survival seemed to be more pronounced than that of HIPEC. Further research is indicated to evaluate and compare the possible benefits and adverse effects associated with both treatments.

Outcomes of elderly patients undergoing cytoreductive surgery and perioperative intraperitoneal chemotherapy for colorectal cancer peritoneal carcinomatosis

BACKGROUND

The combined treatment of cytoreductive surgery (CRS) and perioperative chemotherapy (PIC) for colorectal peritoneal carcinomatosis (PC) is a rigorous surgical treatment most suited for fit and young patients. With technical maturity and improved perioperative care, we examined the outcomes of elderly patients undergoing CRS and PIC for colorectal PC.

METHODS

All consecutive patients treated in two tertiary centers for PC of colorectal cancer who were 70 years of age or older at the time of surgery were included. Data on patient characteristics, concomitant diseases, operation details, perioperative course, and follow-up were retrieved from medical charts. Primary outcomes were perioperative morbidity and mortality. Secondary outcomes were disease-free and overall survival.

RESULTS

Twenty-four patients (11 male) were included in this study (mean age 73.5 years). In eight patients major complications occurred. In six patients the postoperative course was complicated by minor adverse events. There was no perioperative mortality. Median overall survival was 35 months with a 6, 12, and 18 months survival rate of 94%, 83%, and 68%, respectively.

CONCLUSIONS

CRS and PIC for colorectal PC may be safely performed with acceptable morbidity in selected elderly patients. When considering patients for surgery, performance status, and the disease extent should be used as eligibility criteria rather than age.

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy improves survival of gastric cancer with peritoneal carcinomatosis: evidence from an experimental study

Background

Cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) has been considered as a promising treatment modality for gastric cancer with peritoneal carcinomatosis (PC). However, there have also been many debates regarding the efficacy and safety of this new approach. Results from experimental animal model study could help provide reliable information. This study was to investigate the safety and efficacy of CRS + HIPEC to treat gastric cancer with PC in a rabbit model.

Methods

VX2 tumor cells were injected into the gastric submucosa of 42 male New Zealand rabbits using a laparotomic implantation technique, to construct rabbit model of gastric cancer with PC. The rabbits were randomized into control group (n = 14), CRS alone group (n = 14) and CRS + HIPEC group (n = 14). The control group was observed for natural course of disease progression. Treatments were started on day 9 after tumor cells inoculation, including maximal removal of tumor nodules in CRS alone group, and maximal CRS plus heperthermic intraperitoneal chemoperfusion with docetaxel (10 mg/rabbit) and carboplatin (40 mg/rabbit) at 42.0 ± 0.5°C for 30 min in CRS + HIPEC group. The primary endpoint was overall survival (OS). The secondary endpoints were body weight, biochemistry, major organ functions and serious adverse events (SAE).

Results

Rabbit model of gastric cancer with PC was successfully established in all animals. The clinicopathological features of the model were similar to human gastric PC. The median OS was 24.0 d (95% confidence interval 21.8 - 26.2 d ) in the control group, 25.0 d (95% CI 21.3 - 28.7 d ) in CRS group, and 40.0 d (95% CI 34.6 - 45.4 d ) in CRS + HIPEC group (P = 0.00, log rank test). Compared with CRS only or control group, CRS + HIPEC could extend the OS by at least 15 d (60%). At the baseline, on the day of surgery and on day 8 after surgery, the peripheral blood cells counts, liver and kidney functions, and biochemistry parameters were all comparable. SAE occurred in 0 animal in control group, 2 animals in CRS alone group including 1 animal death due to anesthesia overdose and another death due to postoperative hemorrhage, and 3 animals in CRS + HIPEC group including 1 animal death due to anesthesia overdose, and 2 animal deaths due to diarrhea 23 and 27 d after operation.

Conclusions

In this rabbit model of gastric cancer with PC, CRS alone could not bring benefit while CRS + HIPEC with docetaxel and carboplatin could significantly prolong the survival with acceptable safety.