Piroxicam and intracavitary platinum-based chemotherapy for the treatment of advanced mesothelioma in pets: preliminary observations

Solid epithelioid peritoneal mesothelioma with pulmonary metastasis in feline

Mesothelioma is a rare malignant neoplasm that affects the mesothelial cells lining the thoracic and abdominal cavities, such as the pleura, peritoneum, and pericardium. It is most prevalent in dogs and cattle, but the causes of this disease in animals are uncertain. In felines, it mainly affects the pleura, with an unfavorable prognosis. This paper explores a rare case of metastatic peritoneal mesothelioma in a 2-year-old female mixed breed cat, emphasizing its uniqueness due to the feline's age. The patient, previously treated at a private clinic, presented moderate abdominal distension as the only clinical sign. Abdominal ultrasound and peritoneal fluid cytology led to the provisional diagnosis of mesothelioma/carcinomatosis. One day after exploratory laparotomy, the animal died and was subsequently sent for necropsy. During macroscopic analysis, nodules were observed in the peritoneum, diaphragm, omentum, stomach serosa, and large intestine, and the diagnosis of solid epithelioid peritoneal mesothelioma with lung metastasis was confirmed after microscopic analysis. The diagnosis of mesothelioma is challenging, and the importance of immunohistochemical panels with specific markers such as cytokeratin AE1/AE3 and calretinin is highlighted. Considering that mesothelioma is a pathology with a poor prognosis, it is essential to include this disease in the list of differential diagnoses within veterinary oncology.

Establishment of an experimental model of canine malignant mesothelioma organoid culture using a three-dimensional culture method

Canine malignant mesothelioma (cMM) is a rare and drug-resistant malignant tumor. Due to few patients and experimental models, there have not been enough studies to demonstrate the pathogenesis of the disease and novel effective treatment for cMM. Since cMM resembles human MM (hMM) in histopathological characteristics, it is also considered a promising research model of hMM. Compared with conventional 2-dimensional (2D) culture methods, 3-dimensional (3D) organoid culture can recapitulate the properties of original tumor tissues. However, cMM organoids have never been developed. In the present study, we for the first time generated cMM organoids using the pleural effusion samples. Organoids from individual MM dogs were successfully generated. They exhibited the characteristics of MM and expressed mesothelial cell markers, such as WT-1 and mesothelin. The sensitivity to anti-cancer drugs was different in each strain of cMM organoids. RNA sequencing analysis showed cell adhesion molecule pathways were specifically upregulated in cMM organoids compared with their corresponding 2D cultured cells. Among these genes, the expression level of E-cadherin was drastically higher in the organoids than that in the 2D cells. In conclusion, our established cMM organoids might become a new experimental tool to provide new insights into canine and human MM therapy.

Thoracoscopic Assisted PleuralPortTM Application in Seven Dogs Affected by Chronic Pleural Effusion

Chronic non-septic pleural effusion is a condition that frequently may occur because of lung or pleural neoplasia, or chylothorax refractory to surgical treatment, in dogs. Effusion management can be performed with multiple pleurocenteses or the application of chest drains. New modified vascular devices have been used for patients with chronic diseases; they offer the advantage of allowing home management and do not require hospitalization. Eight PleuralPort^TM devices were applied in seven dogs during thoracoscopic exploration and biopsy procedures; five were affected by mesothelioma; one by lung metastases from a mammary carcinoma; and one by chronic chylothorax. The median time of surgical procedure was 51 min; one developed pneumothorax post-operatively that resolved within 12 h after repeated drainage; one device was obstructed after 45 days and was successfully managed by flushing. All patients were discharged after 24 h. The median duration of port insertion in cancer patients was 5 months and those dogs were euthanized because of tumor progression; in the dog with chylothorax, the device was removed after 1 year when the effusion had resolved.

Thymic squamous cell carcinoma in a cat

Background

The most common cranial mediastinal masses affecting dogs and cats include lymphoma and thymic epithelial tumors. In this report, a cat with a cranial mediastinal mass was diagnosed with a thymic carcinoma subtype squamous cell carcinoma, which has rarely been reported in cats. Management of this subtype with a combination of surgery and chemotherapy has so far not been reported. This case report describes the treatment with surgical management followed by intracavitary carboplatin.

Case Description

A 12-year-old male neutered domestic short hair cat was referred for lethargy, hyporexia, and weight loss, and was diagnosed with a cranial mediastinal mass radiographically. Initial cytology through fine needle aspirates was suggestive of carcinoma. Computed tomography was performed which did not show evidence of other primary tumor sources or metastases, and hence surgical resection was recommended. Intraoperative findings revealed local invasion of the surrounding tissues, including major vasculature and nerves, although histopathological assessment showed no local lymph node involvement. Intracavitary carboplatin chemotherapy was administered 2 weeks postsurgery. The patient was humanely euthanized 4 weeks postsurgery due to evidence of local recurrence causing significant respiratory compromise.

Conclusion

A combination of surgical excision as well as intracavitary carboplatin does not seem to be effective for the treatment of this thymic carcinoma subtype, with evidence of early recurrence and return of clinical signs.

Clinical presentation, treatment and outcome of canine malignant mesothelioma: A retrospective study of 34 cases

Canine malignant mesothelioma (CMM) is a rare and aggressive tumour associated with a poor prognosis. Limited information is available regarding effective treatment options and prognostic factors. The purpose of this retrospective case series was to describe the clinical presentation, treatment and survival in a cohort of dogs with this disease and to investigate possible prognostic factors. Thirty-four dogs were included. Tachypnoea and dyspnoea due to pleural effusion were the most common presenting clinical signs. Twenty-two dogs had a subcutaneous access port placed and 25 dogs were treated with intracavitary and/or intravenous chemotherapy. The main protocols used were single-agent 5-FU (n = 14) and carboplatin single-agent or alternated with mitoxantrone (n = 10). The overall response rate (defined as more than 25% reduction in effusion volume) to chemotherapy treatment was 37% after 3-weeks and 24% after 15-weeks. The median survival time (MST) for all dogs was 195 days (95% CI 53-324). MST was 234 days for dogs receiving chemotherapy and 29 days for dogs not receiving chemotherapy. The 1-year survival rate was 22% for all dogs. Treatment with chemotherapy was the only significant prognostic factor associated with survival (p = .001). Further studies are needed to determine the optimal treatment approach for malignant mesothelioma in dogs. Nevertheless, effusion recurrence should be expected and the prognosis for these patients in the long-term is poor.

Case Report: Microfragmented Adipose Tissue Drug Delivery in Canine Mesothelioma: A Case Report on Safety, Feasibility, and Clinical Findings

Mesothelioma is a rare lethal tumor of dogs and humans involving cavities of the body. Dogs are considered a model for new drugs and therapeutic methods since they present spontaneous diseases similar to humans. Microfragmented adipose tissue (MFAT) uploaded by paclitaxel (PTX) is a drug delivery medium providing slow release of chemotherapic drugs. A dog affected by pleural, pericardial, and peritoneal mesothelioma was treated by 17 intracavitary ultrasound-guided injections of MFAT-PTX over 22 months. A long-lasting improvement of general conditions was observed, treatment was well-tolerated, and no toxicity or hypersensitivity was reported. Pharmacokinetic (PK) data indicated low drug localization in the circulatory system and a tendency to enter or remain in the extravascular compartments of the body. Indeed, low levels of free-circulating drugs for a short time produced low toxicity, whereas, a higher intracavitary PTX concentration can have major pharmacological efficacy. To our knowledge, this is the first time that mesothelioma has been treated using such a procedure, and this should be considered as a novel therapeutic approach. The low systemic absorption suggests the possible role of MFAT-PTX for loco-regional/intratumoral therapy also useful in other types of tumors, and further investigation is warranted.

Curcumin as an Anticancer Agent in Malignant Mesothelioma: A Review

Malignant mesothelioma is an infrequent tumor that initiates from the mesothelial cells lining of body cavities. The great majority of mesotheliomas originate in the pleural cavity, while the remaining cases initiate in the peritoneal cavity, in the pericardial cavity or on the tunica vaginalis. Usually, mesotheliomas grow in a diffuse pattern and tend to enclose and compress the organs in the various body cavities. Mesothelioma incidence is increasing worldwide and still today, the prognosis is very poor, with a reported median survival of approximately one year from presentation. Thus, the development of alternative and more effective therapies is currently an urgent requirement. The aim of this review article was to describe recent findings about the anti-cancer activity of curcumin and some of its derivatives on mesotheliomas. The potential clinical implications of these findings are discussed.

Evaluation of intracavitary carboplatin chemotherapy for treatment of pleural carcinomatosis in cats: a retrospective study of eight cases

OBJECTIVES

The aim of this study was to evaluate the benefit of intracavitary carboplatin chemotherapy in cats with malignant pleural effusion of epithelial origin.

METHODS

The medical records of cats with a cytological diagnosis of neoplastic pleural effusion of epithelial origin were reviewed at three referral institutions between January 2013 and June 2018. Only cats treated with intracavitary carboplatin chemotherapy were enrolled. Data collection included signalment, medical history, clinical signs, pleural effusion analysis, diagnostic imaging findings, intracavitary carboplatin chemotherapy protocol, adverse events, response to chemotherapy, outcome and underlying primary tumour, if possible.

RESULTS

Eight cats met the inclusion criteria. Three cats had previous surgical removal of a tumour, including a poorly differentiated primary lung carcinoma, a uterine adenocarcinoma and a benign mammary tumour. The main clinical signs were tachypnoea and/or dyspnoea, inappetence and weight loss. Thoracic radiographs revealed marked bilateral pleural effusion in all cats. Pleural fluid analysis was consistent with a modified transudate, with malignant epithelial cells on cytology, leading to a diagnosis of pleural carcinomatosis. All cats received only one cycle of intracavitary carboplatin chemotherapy at a dose of 200-240 mg/m2. Recurrence of pleural effusion was reported in 7/8 cats within 4-15 days of chemotherapy, and death was recorded in all cats within 5-16 days, owing to recurrent pleural effusion or poor general condition. The primary cancer was suspected to be of pulmonary, mammary and pancreatic origin in four cats, two cats and one cat, respectively, and of unknown origin in the remaining cat.

CONCLUSIONS AND RELEVANCE

In this study, intracavitary carboplatin chemotherapy seems ineffective in managing neoplastic pleural effusion of epithelial origin in cats with pleural carcinomatosis. Other cytotoxic drugs and/or techniques should be investigated in the future to improve the quality of life and survival of cats with pleural carcinomatosis.

Presumptive seeding metastasis of pericardial mesothelioma following repeated pericardiocentesis in a dog

A dog with a history of recurrent pericardial effusion that required repeated pericardiocentesis was presented to the surgical service at the Ontario Veterinary College Health Sciences Centre for thoracoscopic pericardiectomy. Physical examination revealed a subcutaneous mass in the right lateral thorax. Cytology of the subcutaneous mass and histopathology of the pericardium were consistent with mesothelioma. This article details the first reported case of pericardial mesothelioma with suspected extra-thoracic metastasis following pericardiocentesis in a dog.

Curcumin C3 complex®/Bioperine® has antineoplastic activity in mesothelioma: an in vitro and in vivo analysis

BACKGROUND

A major limitation in the treatment for malignant mesothelioma is related to serious side effects caused by chemotherapeutics and to the development of cancer-resistance. Advances in cancer therapies have been reached thanks to the introduction of alternative approaches, such as the use of phytochemicals. Curcumin-C3complex®/Bioperine® is a commercially standardized extract containing a ratio-defined mixture of three curcuminoids and piperine that greatly increase its bioavailability. Interestingly, the anticancer effect of this formulation has been described in different studies and several clinical trials have been started, but to our knowledge none refers to human mesothelioma.

METHODS

Curcumin-C3complex®/Bioperine® anticancer effect was evaluated in vitro in different human mesothelioma cell lines analysing cell proliferation, colony-forming assay, wound healing assays, invasion assay and FACS analysis. In vivo anticancer properties were analysed in a mesothelioma xenograft mouse model in CD1 Nude mice.

RESULTS

Curcumin-C3complex®/Bioperine® in vitro induced growth inhibition in all mesothelioma cell lines analysed in a dose- and time-depended manner and reduced self-renewal cell migration and cell invasive ability. Cell death was due to apoptosis. The analysis of the molecular signalling pathway suggested that intrinsic apoptotic pathway is activated by this treatment. This treatment in vivo delayed the growth of the ectopic tumours in a mesothelioma xenograft mouse model.

CONCLUSIONS

Curcumin-C3complex®/Bioperine® treatment strongly reduces in vitro tumorigenic properties of mesothelioma cells by impairing cellular self-renewal ability, proliferative cell rate and cell migration and delays tumor growth in xenograft mouse model by reducing angiogenesis and increasing apoptosis. Considering that curcumin in vivo synergizes drug effects, its administration to treatment regimen may help to enhance drug therapeutic efficacy in mesothelioma. Our results suggest that implementation of standard pharmacological therapies with novel compounds may pave the way to develop alternative approaches to mesothelioma.

Toxico-Neurological Effects of Piroxicam in Monogastric Animals

Piroxicam is a benzothiazine compound with anti-inflammatory, antipyretic, and analgesic properties. Because of the very high efficacy of piroxicam and its increasing use in the treatment of carcinomas in dogs and cats, there is a need for acute toxicity study of piroxicam in monogastric animals and its potential for causing secondary poisoning in puppies. Piroxicam manufactured by Shanxi Federal Pharmaceutical Co, Ltd. was used for this study. Revised up-and-down procedure was used for the estimation of median lethal dose in mouse (259.4 ± 51.9 mg/kg), rat (259.4 ± 69.6 mg/kg), rabbit (707.5 ± 130.8 mg/kg), cat (437.5 ± 128.1 mg/kg), guinea pig (218.7 ± 64.1 mg/kg), monkey (733.3 ± 83.3 mg/kg), broiler (285.3 ± 62.5 mg/kg), hen (638.3 ± 115.4 mg/kg), turkey (707.5 ± 130.8 mg/kg), pigeon (375 ± 55.9 mg/kg), and duck (311.3 ± 46.6 mg/kg). The acute toxicity signs of piroxicam at doses 207.5 mg/kg and above observed in the animals are torticollis, opisthotonos, somnolence, lethargy, diarrhea, gastroenteritis, generalized internal bleeding, anemia, congestion of the lung and liver, flaccid paralysis, cheesy lung, urinary incontinence, engorged urinary bladder, convulsive jerking of the limbs, lying in ventral recumbency, gasping for air, roaring, and death. Three out of six puppies died after being fed the carcasses of poisoned turkey, duck, and hen administered piroxicam at doses of 1000, 415, and 1000 mg/kg, respectively. White flaky cheesy materials observed in turkeys were also observed in the gastrointestinal content of the puppies. Paleness of carcasses, watery crop content, dryness of pericardium, gastroenteritis, intestinal perforation, and whitish pericardium were observed in broilers. There were effusions in thoracic and abdominal cavities as seen in all other carcasses poisoned primarily by piroxicam. Administration of atropine (0.02 mg/kg) led to survival of the remaining puppies. In conclusion, piroxicam is very to moderately toxic in monogastric animals.

Peritoneal fibrosarcomatous mesothelioma in a cat

Primary tumors of serosal surfaces are uncommon in veterinary medicine. Mesothelial neoplasms can be benign or malignant, and are classified as predominantly epitheloid, mixed (biphasic), or fibrous (spindle cell, fibrosarcomatous), with fibrous mesotheliomas reported least in domestic species. A 9-year-old Domestic Shorthair cat presented on emergency with a brief history of weakness and lethargy. On presentation, the cat was semicomatose, hypothermic, and hypotensive with a markedly distended abdomen. Approximately 1 liter of serosanguineous fluid was removed via abdominocentesis. Diagnostic imaging and cytologic evaluation of fine-needle aspirates were suggestive of neoplasia, and the cat was subsequently euthanized. At necropsy, the omentum was contracted cranially into an irregular lobular mass that surrounded the stomach and proximal intestinal tract, and focally infiltrated the spleen. Both visceral and parietal peritoneal surfaces were thickened and contained off-white friable material and occasionally firm fibrous plaques. Microscopically, serosal surfaces were expanded by neoplastic spindle cells, which were often accompanied by moderate to abundant fibrous stroma. Neoplastic cells had varying degrees of immunoreactivity for cytokeratin, vimentin, desmin, and smooth muscle actin, which was consistent with the diagnosis of mesothelioma.

Apoptosis induced by piroxicam plus cisplatin combined treatment is triggered by p21 in mesothelioma

BACKGROUND

Malignant mesothelioma (MM) is a rare, highly aggressive tumor, associated to asbestos exposure. To date no chemotherapy regimen for MM has proven to be definitively curative, and new therapies for MM treatment need to be developed. We have previously shown in vivo that piroxicam/cisplatin combined treatment in MM, specifically acts on cell cycle regulation triggering apoptosis, with survival increase.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed, at molecular level, the apoptotic increase caused by piroxicam/cisplatin treatment in MM cell lines. By means of genome wide analyses, we analyzed transcriptional gene deregulation both after the single piroxicam or cisplatin and the combined treatment. Here we show that apoptotic increase following combined treatment is mediated by p21, since apoptotic increase in piroxicam/cisplatin combined treatment is abolished upon p21 silencing.

CONCLUSIONS/SIGNIFICANCE

Piroxicam/cisplatin combined treatment determines an apoptosis increase in MM cells, which is dependent on the p21 expression. The results provided suggest that piroxicam/cisplatin combination might be tested in clinical settings in tumor specimens that express p21.

Malignant Mesothelioma of the Tunica Vaginalis Testis in a Dog: Histological and Immunohistochemical Characterization

Histologic and immunohistochemical features of a malignant mesothelioma of the testicular tunica vaginalis in a 9-year-old male mixed-breed dog are reported. The dog had a large scrotal swelling determined by ultrasonography to be a heterogeneous irregular mass characterized by a mixed echogenic pattern and located in the left vaginal canal of the testis. Histologically, the neoplasm was nodular, was poorly demarcated, and consisted of pleomorphic cells that were associated with a significant desmoplastic reaction. By immunohistochemistry, neoplastic cells stained positively for cytokeratin and vimentin and were immunoreactive with an antimesothelial cell monoclonal antibody. Malignant mesotheliomas of tunica vaginalis testis are rare in mammalian species, including dogs.

Evaluation of adverse events in cats receiving long-term piroxicam therapy for various neoplasms

The role of cyclo-oxygenase 2 (COX-2) and prostaglandins (PG) in carcinogenesis has been documented in many species. Piroxicam has shown efficacy against several neoplasms and is frequently prescribed for chronic use. There are no studies investigating chronic piroxicam administration in cats and the chronic use of non-steroidal anti-inflammatory agents in this species has long been cautioned against. This retrospective study aimed to evaluate adverse effects in cats receiving long-term daily piroxicam. Seventy-three cats received daily piroxicam at doses of 0.13-0.41mg/kg. Treatment duration ranged from 1 to 38 months. Treatment with piroxicam was found to significantly increase frequency of vomiting during the first month of therapy, though this was most significant for cats receiving concurrent chemotherapy. Piroxicam administration was not significantly associated with hematologic, renal or hepatic toxicities. Adverse events were not correlated with dosage. Adverse events were reported in 29% of cats, and were generally mild and transient. Eight percent discontinued piroxicam due to adverse reaction, and 4% due to difficult administration. This study indicates that long-term daily piroxicam is generally well tolerated in cats at conventional doses.

Global gene expression profiling of human pleural mesotheliomas: identification of matrix metalloproteinase 14 (MMP-14) as potential tumour target

BACKGROUND

The goal of our study was to molecularly dissect mesothelioma tumour pathways by mean of microarray technologies in order to identify new tumour biomarkers that could be used as early diagnostic markers and possibly as specific molecular therapeutic targets.

METHODOLOGY

We performed Affymetrix HGU133A plus 2.0 microarray analysis, containing probes for about 39,000 human transcripts, comparing 9 human pleural mesotheliomas with 4 normal pleural specimens. Stringent statistical feature selection detected a set of differentially expressed genes that have been further evaluated to identify potential biomarkers to be used in early diagnostics. Selected genes were confirmed by RT-PCR. As reported by other mesothelioma profiling studies, most of genes are involved in G2/M transition. Our list contains several genes previously described as prognostic classifier. Furthermore, we found novel genes, never associated before to mesotheliom that could be involved in tumour progression. Notable is the identification of MMP-14, a member of matrix metalloproteinase family. In a cohort of 70 mesothelioma patients, we found by a multivariate Cox regression analysis, that the only parameter influencing overall survival was expression of MMP14. The calculated relative risk of death in MM patients with low MMP14 expression was significantly lower than patients with high MMp14 expression (P = 0.002).

CONCLUSIONS

Based on the results provided, this molecule could be viewed as a new and effective therapeutic target to test for the cure of mesothelioma.

Expression of the embryonic lethal abnormal vision-like protein HuR in human mesothelioma: association with cyclooxygenase-2 and prognosis

BACKGROUND

The human embryonic lethal abnormal vision (ELAV)-like protein HuR is a messenger RNA (mRNA)-binding protein that controls the stability of certain transcripts, including cyclooxygenase2 (COX-2).

METHODS

To investigate a possible contribution of dysregulation of mRNA stability to the progression of cancer and to COX-2 over expression in mesothelioma, the authors studied expression of COX-2 and HuR in 5 mesothelioma cell lines (MSTO, NCI, Ist-Mes1, Ist-Mes2, and MPP89) and in a group of 29 human mesothelioma specimens that were characterized previously for COX-2 expression.

RESULTS

All 5 cell lines expressed HuR, whereas COX-2 was not detectable in MSTO or NCI cells. Treatment with cytokines induced a shift in systolic HuR protein levels in MPP89 and Ist-Mes2 cells that was accompanied by an increase in the expression of COX-2 mRNA and protein. In Ist-Mes1 cells, cytokine stimulation did not cause the passage of HuR from nucleus to cytoplasm, and the synthesis of COX-2 did not increase. In tumor tissues, immunohistochemistry revealed a positive, statistically significant correlation between high COX-2 expression and cytoplasmic localization of HuR (P = .016). Moreover, on univariate analysis, overall survival was found to be influenced strongly by cytoplasmic HuR localization (P = .004).

CONCLUSIONS

The current results suggested that HuR plays a role in tumor progression in mesothelioma and that COX-2 may be a target of its activity in neoplastic cells. Together, these observations indicate that strategies aiming toward the modulation of HuR may have a potential clinical benefit in mesothelioma.

The serine protease HtrA1 is a novel prognostic factor for human mesothelioma

AIMS

The objective of our study was to analyze the potential prognostic value of the expression of the serine protease HtrA1 and of EGFR in 70 malignant mesotheliomas.

MATERIALS & METHODS

Immunohistochemistry was used to determine the expression of HtrA1 and EGFR. Univariate and multivariate analyses were used to correlate expression of these molecular factors in combination with available clinicopathologic data to patient survival.

RESULTS

A positive, statistically significant relationship has been recorded between HtrA1 expression level and survival (p < 0.0001). By contrast, a negative relationship has been identified between EGFR expression and survival (p = 0.02). Moreover, extension of the tumor (T) and involvement of lymph nodes (N) advanced status (p = 0.001 and 0.002, respectively), as well as the sarcomatoid histotype (p = 0.005), correlated significantly with poor survival. Finally, by a multivariate Cox regression analysis, the only immunohistochemical parameter that resulted to influence overall survival was HtrA1 (p = 0.0001). Interestingly, the prognostic value of HtrA1 expression was completely independent from EGFR expression (p < 0.0001).

CONCLUSION

This is the first study of the relationship between HtrA1 expression and survival of mesothelioma patients. The data obtained strongly indicate the utilization of HtrA1 expression as a prognostic parameter for mesothelioma and suggest this serine protease as a possible molecular target for the treatment of malignant mesotheliomas.

Molecular analysis of the effects of Piroxicam and Cisplatin on mesothelioma cells growth and viability

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been proposed for prevention and treatment of a variety of human cancers. Piroxicam, in particular, has been recently shown to exert significant anti-tumoral activity in combination with cisplatin (CDDP) on mesothelioma cells. However, the mechanisms through which NSAIDs regulate the cell cycle as well as the signal pathways involved in the growth inhibition, remain unclear. In the present study, using two mesothelioma cell lines, MSTO-211H and NCI-H2452, we have investigated the influence of piroxicam alone and in association with CDDP on proliferation, cell cycle regulation and apoptosis. In both cell lines a significant effect on cell growth inhibition, respect to the control, was observed with all the drugs tested. Moreover, treatment with piroxicam or CDDP alone altered the cell cycle phase distribution as well as the expression of some cell cycle regulatory proteins in both cell lines. These effects were increased, even if in a not completely overlapping manner, after treatment with the association of piroxicam and CDDP. In particular, the two drugs in NCI cell line had a synergistic effect on apoptosis, probably through activation of caspase 8 and caspase 9, while the most evident targets among the cell cycle regulators were cyclin D1 and p21waf1. These results suggest that the association of piroxicam and CDDP specifically triggers cell cycle regulation and apoptosis in different mesothelioma cell lines and may hold promise in the treatment of mesothelioma.