Mitotane enhances cytotoxicity of chemotherapy in cell lines expressing a multidrug resistance gene (mdr-1/P-glycoprotein) which is also expressed by adrenocortical carcinomas

Exposure to anticancer drugs modulates the expression of ACSL4 and ABCG2 proteins in adrenocortical carcinoma cells

Adrenocortical carcinoma (ACC) is a rare and malignant disease, with more than 50 % of patients developing hormone-secreting tumors. These tumors are genetically heterogeneous and potentially lethal, as metastasis is often underway at the time of diagnosis. While chemoresistance can be multifactorial, Acyl CoA synthetase 4 (ACSL4) is known to contribute to the generation of highly aggressive cellular phenotypes, while increased expression and activity of multidrug transporters such as ATP-binding cassette subfamily G member 2 (ABCG2) are known to play a key role. Therefore, the objective of this work was to determine changes in the expression of ACSL4 and ABCG2 in ACC cell lines after exposure to antitumor drugs. Bioinformatics analysis of public database GSE140818 revealed higher ACSL4 and ABCG2 expression in HAC15 cells resistant to mitotane when compared to wild type cells. In addition, our studies revealed an increase in ACSL4 and ABCG2 expression in lowly aggressive H295R cells undergoing early treatment with non-lethal concentrations of mitotane, doxorubicin and cisplatin. Comparable results were obtained in lowly aggressive breast cancer cells MCF-7. The increase in ACSL4 and ABCG2 expression favored tumor cell viability, proliferation and compound efflux, an effect partially offset by ACSL4 and ABCG2 inhibitors. These results provide relevant data on the undesired molecular effects of antitumor drugs and may fuel future studies on patients' early response to antitumor treatment.

Update on Biology and Genomics of Adrenocortical Carcinomas: Rationale for Emerging Therapies

The adrenal glands are paired endocrine organs that produce steroid hormones and catecholamines required for life. Adrenocortical carcinoma (ACC) is a rare and often fatal cancer of the peripheral domain of the gland, the adrenal cortex. Recent research in adrenal development, homeostasis, and disease have refined our understanding of the cellular and molecular programs controlling cortical growth and renewal, uncovering crucial clues into how physiologic programs are hijacked in early and late stages of malignant neoplasia. Alongside these studies, genome-wide approaches to examine adrenocortical tumors have transformed our understanding of ACC biology, and revealed that ACC is composed of distinct molecular subtypes associated with favorable, intermediate, and dismal clinical outcomes. The homogeneous transcriptional and epigenetic programs prevailing in each ACC subtype suggest likely susceptibility to any of a plethora of existing and novel targeted agents, with the caveat that therapeutic response may ultimately be limited by cancer cell plasticity. Despite enormous biomedical research advances in the last decade, the only potentially curative therapy for ACC to date is primary surgical resection, and up to 75% of patients will develop metastatic disease refractory to standard-of-care adjuvant mitotane and cytotoxic chemotherapy. A comprehensive, integrated, and current bench-to-bedside understanding of our field's investigations into adrenocortical physiology and neoplasia is crucial to developing novel clinical tools and approaches to equip the one-in-a-million patient fighting this devastating disease.

Phase II study of cabazitaxel as second-third line treatment in patients with metastatic adrenocortical carcinoma

Background

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy with a poor prognosis. No efficacious treatment options are currently available for patients with advanced metastatic disease with disease progression to standard etoposide, doxorubicin, cisplatin and mitotane (EDP-M) therapy. We assessed the activity and tolerability of cabazitaxel as a second/third-line approach in metastatic ACC.

Patients and methods

Patients included in this single-center, phase II study (ClinicalTrials.gov identifier NCT03257891) had disease progression to a cisplatin-containing regimen (such as EDP) plus mitotane, plus/minus a further chemotherapy line. Cabazitaxel was administered intravenously at 25 mg/m² on day 1 of a 21-day cycle, for a maximum of six cycles. The primary endpoint was a disease control rate after 4 months.

Results

From March 2018 to September 2019, 25 eligible patients were enrolled. A disease control rate after 4 months was obtained in six patients (24%). No patients attained a disease response according to RECIST 1.1, 9 patients (36%) had stable disease and 16 patients (64%) progressive disease. Median progression-free survival and overall survival were 1.5 months (range 0.3-7 months) and 6 months (range 1-22.2 months), respectively. Cabazitaxel therapy was well tolerated and only three (12%) patients developed grade 3 toxicity which were nausea in one patient (4%) and anemia in two patients (8%).

Conclusions

Cabazitaxel has a manageable toxicity profile but is poorly active as second/third-line treatment in advanced ACC patients. These results do not support further evaluation of cabazitaxel in this setting.

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Cabazitaxel is well tolerated but poorly active as second/third-line treatment in patients with advanced ACC.

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Combining RECIST and Choi criteria could be of value in the assessment of disease response to chemotherapy in ACC patients.

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Older age, elevated cortisol and LDH blood level correlate with a greater risk of death in multivariate analysis.

Re-Evaluation of Combinational Efficacy and Synergy of the Italian Protocol In Vitro: Are We Truly Optimizing Benefit or Permitting Unwanted Toxicity?

Introduction: Adrenocortical carcinoma (ACC) is a rare endocrine malignancy, with very poor prognosis as a majority of the patients have advanced disease at the time of diagnosis. Currently, adjuvant therapy for most patients consists of either mitotane (M) alone or in combination with multi-drug chemotherapeutics such as etoposide (E), doxorubicin (D), and cisplatin (P), known as the Italian protocol (IP; EDPM). This multi-drug treatment regimen, however, carries significant toxicity potential for patients. One way to improve toxicity profiles with these drugs in combination is to understand where their synergy occurs and over what dosing range so that lower dose regimens could be applied in combination with equal or improved efficacy. We hypothesize that a better understanding of the synergistic effects as well as the regulation of steroidogenic enzymes during combination therapy may provide more optimized combinational options with good potency and lower toxicity profiles. Methods: Two human ACC cell lines, NCI-H295R (hormonally active) and SW13 (hormonally inactive), were grown in 2D culture in appropriate growth medium. The viability of the cells after treatment with varying concentrations of the drugs (E, D, and P) either alone or in combinations with M was determined using the CellTiter Glow assay after 72 h, and the combination index for each was calculated using Compusyn by the Chou–Talalay method. The expression levels of enzymes associated with steroidogenesis were evaluated by RT-PCR in NCI-H295R. Results: When both cell lines were treated with M (ranging 25–50 μM), +E (ranging 18.75–75 μM), and +D (ranging 0.625–2.5 μM) we observed a synergistic effect (CI < 1) with potency equivalent to the full Italian protocol (IP), whereas combining M + P + D had an antagonistic effect (CI > 1) indicating the negative effect of adding cisplatin in the combination. Comparing the hormonally active and inactive cell lines, M + P + E was antagonistic in NCI-H295R and synergistic in SW13. Treatment of NCI-H295R cells with antagonistic combinations (M + P + D, M + P + E) resulted in a significant decrease in the levels of steroidogenic enzymes STAR, CYP11A1, and CYP21A2 compared to IP (p < 0.05) while M + E + D resulted in increased expression or no significant effect compared to IP across all genes tested. Conclusions: The synergistic effect for M + E + D was significant and equivalent in potency to the full IP in both cell lines and resulted in a steroidogenic gene expression profile similar to or better than that of full IP, warranting further evaluation. Future in vivo evaluation of the combination of M + E + D (with removal of P from the IP regimen) may lower toxicity while maintaining anticancer efficacy in ACC.

Advanced adrenocortical carcinoma successfully treated with gemcitabine plus capecitabine as second-line chemotherapy

INTRODUCTION

Adrenocortical carcinoma is a rare malignant tumor with an unfavorable prognosis in the advanced stage for which second-/third-line chemotherapy is not well established.

CASE PRESENTATION

A 34-year-old woman was referred to our institution for left adrenal tumor with multiple liver metastases and tumor thrombus extending to the inferior vena cava. According to her clinical diagnosis of adrenocortical carcinoma (T4N0M1, European Network for the Study of Adrenal Tumors stage IV), we resected the left adrenal tumor and tumor thrombus. Pathological examination confirmed the adrenocortical carcinoma diagnosis. After four courses of etoposide, doxorubicin, cisplatin, and mitotane therapy, the liver metastases progressed, and we started gemcitabine, capecitabine, and mitotane therapy as second-line chemotherapy. After 7 months, significant shrinkage of the liver metastases was observed, and they remained stable over 16 months.

CONCLUSION

We reported a case of advanced adrenocortical carcinoma with significant shrinkage of liver metastases following gemcitabine, capecitabine, and mitotane therapy, with the effect maintained over 16 months.

Efficacy of the EDP-M Scheme Plus Adjunctive Surgery in the Management of Patients with Advanced Adrenocortical Carcinoma: The Brescia Experience

Etoposide, doxorubicin and cisplatin plus oral mitotane (EDP-M) comprise the reference regimen in the management of patients with adrenocortical carcinoma (ACC). In this paper, we described the outcome of 58 patients with advanced/metastatic ACC consecutively treated with EDP-M in a reference center for this rare disease in Italy. In this series, EDP-M obtained a partial response in 50% of patients; median progression free survival (PFS) and overall survival were 10.1 months (95% Confidence Interval [CI 95%] 8.1–12.8) and 18.7 months (95% CI: 14.6–22.8), respectively. EDP-M was not interrupted in five patients showing disease progression after two cycles without the appearance of new lesions and mitotane levels below the therapeutic range. In two of them, the disease remained stable at further imaging evaluations and the other three obtained a partial response. Twenty-six responding patients underwent surgery of residual disease and 13 of them became disease free. Surgery identified a pathological complete response (pCR) in four patients (7%) and Ki67 expression in post-chemotherapy tumor specimens, inferior to 15% (median value), was associated with better PFS and survival. In the present study, the EDP-M regimen is confirmed to have a limited efficacy. Early disease progression does not mean treatment inefficacy. Surgery of residual disease in partially responding patients allows for the detection of pCR in few of them and this condition is predictive of long-term survival. Ki67 expression of post-chemotherapy residual disease could be an additional prognostic factor that deserves to be studied further.

Venetoclax, a BCL-2 Inhibitor, Enhances the Efficacy of Chemotherapeutic Agents in Wild-Type ABCG2-Overexpression-Mediated MDR Cancer Cells

Previous studies have shown that small-molecule BCL-2 inhibitors can have a synergistic interaction with ABCG2 substrates in chemotherapy. Venetoclax is a potent and selective BCL-2 inhibitor, approved by the FDA in 2016 for the treatment of patients with chronic lymphocytic leukemia (CLL). This study showed that, at a non-toxic concentration, venetoclax at 10 µM significantly reversed multidrug resistance (MDR) mediated by wild-type ABCG2, without significantly affecting MDR mediated by mutated ABCG2 (R482G and R482T) and ABCB1, while moderate or no reversal effects were observed at lower concentrations (0.5 to 1 µM). The results showed that venetoclax increased the intracellular accumulation of chemotherapeutic agents, which was the result of directly blocking the wild-type ABCG2 efflux function and inhibiting the ATPase activity of ABCG2. Our study demonstrated that venetoclax potentiates the efficacy of wild-type ABCG2 substrate drugs. These findings may provide useful guidance in combination therapy against wild-type ABCG2-mediated MDR cancer in clinical practice.

In vitro cytotoxicity of cabazitaxel in adrenocortical carcinoma cell lines and human adrenocortical carcinoma primary cell cultures☆

Adrenocortical cancer (ACC) is a rare and aggressive malignancy with a poor prognosis. The overall 5-year survival rate of patients with ENS@T stage IV ACC is less than 15%. Systemic antineoplastic therapies have a limited efficacy and new drugs are urgently needed. Human ACC primary cultures and cell lines were used to assess the cytotoxic effect of cabazitaxel, and the role of P-glycoprotein in mediating this effect. Cabazitaxel reduced ACC cell viability, both in ACC cell lines and in ACC primary cell cultures. Molecular and pharmacological targeting of ABCB1/P-gp did not modify its cytotoxic effect in NCI-H295R cells, while it increased the paclitaxel-induced toxicity. Cabazitaxel modified the expression of proteins involved in cellular physiology, such as apoptosis and cell cycle regulation. The drug combination cabazitaxel/mitotane exerted an additive/moderate synergism in different ACC cell experimental models. These results provide a rationale for testing cabazitaxel in a clinical study.

Natural products as multidrug resistance modulators in cancer

Cancer is a prominent cause of death globally. Currently, many drugs that are in clinical practice are having a high prevalence of side effect and multidrug resistance. Risk of tumors acquiring resistance to chemotherapy (multidrug resistance) remains a significant hurdle to the successful treatment of various types of cancer. Membrane-embedded drug transporters, generally overexpressed in cancer, are the leading cause among multiple mechanisms of multidrug resistance (MDR). P-glycoprotein (P-gp) also MDR1/ABCB1, multidrug resistance associated protein 1 (MRP1/ABCC1), MRP2 and breast cancer resistance protein (BCRP/ABCG2) are considered to be a prime factor for induction of MDR. To date, several chemical substances have been tested in a number of clinical trials for their MDR modulatory activity which are not having devoid of any side effects that necessitates to find newer and safer way to tackle the current problem of multidrug resistance in cancer. The present study systematically discusses the various classes of natural products i.e flavonoids, alkaloids, terpenoids, coumarins (from plants, marine, and microorganisms) as potential MDR modulators and/or as a source of promising lead compounds. Recently a bisbenzyl isoquinoline alkaloid namely tetrandrine, isolated from Chinese herb Stephania tetrandra (Han-Fang-Chi) is in clinical trials for its MDR reversal activity.

MDR1 inhibition increases sensitivity to doxorubicin and etoposide in adrenocortical cancer

Chemotherapy for adrenocortical carcinoma (ACC) has limited efficacy and is accompanied by severe toxicity. This lack of effectiveness has been associated with high tumoral levels of the multidrug resistance (MDR) pump P-glycoprotein (P-gp), encoded by the MDR1 gene. In this study, effects of P-gp inhibition on the sensitivity of ACC cells to cytotoxic drugs were evaluated. MDR1 mRNA and P-gp expression were determined in human adrenal tissues and cell lines. H295R, HAC15 and SW13 cells were treated with mitotane, doxorubicin, etoposide, cisplatin and streptozotocin, with or without the P-gp inhibitors verapamil and tariquidar. Cell growth and surviving fraction of colonies were assessed. MDR1 mRNA and P-gp protein expression were lower in ACCs than in adrenocortical adenomas (P < 0.0001; P < 0.01, respectively). MDR1 and P-gp expression were positively correlated in ACC (P < 0.0001, ρ = 0.723). Mitotane, doxorubicin, cisplatin and etoposide dose dependently inhibited cell growth in H295R, HAC15 and SW13. Tariquidar, and in H295R also verapamil, increased the response of HAC15 and H295R to doxorubicin (6.3- and 7.5-fold EC50 decrease in H295R, respectively; all P < 0.0001). Sensitivity to etoposide was increased in H295R and HAC15 by verapamil and tariquidar (all P < 0.0001). Findings were confirmed when assessing colony formation. We show that cytotoxic drugs, except streptozotocin, used for ACC treatment, inhibit ACC cell growth and colony formation at clinically achievable concentrations. P-gp inhibition increases sensitivity to doxorubicin and etoposide, suggesting that MDR1 is involved in sensitivity to these drugs and could be a potential target for cytotoxic treatment improvement in ACC.

European Society of Endocrinology Clinical Practice Guidelines on the management of adrenocortical carcinoma in adults, in collaboration with the European Network for the Study of Adrenal Tumors

Adrenocortical carcinoma (ACC) is a rare and in most cases steroid hormone-producing tumor with variable prognosis. The purpose of these guidelines is to provide clinicians with best possible evidence-based recommendations for clinical management of patients with ACC based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) system. We predefined four main clinical questions, which we judged as particularly important for the management of ACC patients and performed systematic literature searches: (A) What is needed to diagnose an ACC by histopathology? (B) Which are the best prognostic markers in ACC? (C) Is adjuvant therapy able to prevent recurrent disease or reduce mortality after radical resection? (D) What is the best treatment option for macroscopically incompletely resected, recurrent or metastatic disease? Other relevant questions were discussed within the group. Selected Recommendations: (i) We recommend that all patients with suspected and proven ACC are discussed in a multidisciplinary expert team meeting. (ii) We recommend that every patient with (suspected) ACC should undergo careful clinical assessment, detailed endocrine work-up to identify autonomous hormone excess and adrenal-focused imaging. (iii) We recommend that adrenal surgery for (suspected) ACC should be performed only by surgeons experienced in adrenal and oncological surgery aiming at a complete en bloc resection (including resection of oligo-metastatic disease). (iv) We suggest that all suspected ACC should be reviewed by an expert adrenal pathologist using the Weiss score and providing Ki67 index. (v) We suggest adjuvant mitotane treatment in patients after radical surgery that have a perceived high risk of recurrence (ENSAT stage III, or R1 resection, or Ki67 >10%). (vi) For advanced ACC not amenable to complete surgical resection, local therapeutic measures (e.g. radiation therapy, radiofrequency ablation, chemoembolization) are of particular value. However, we suggest against the routine use of adrenal surgery in case of widespread metastatic disease. In these patients, we recommend either mitotane monotherapy or mitotane, etoposide, doxorubicin and cisplatin depending on prognostic parameters. In selected patients with a good response, surgery may be subsequently considered. (vii) In patients with recurrent disease and a disease-free interval of at least 12 months, in whom a complete resection/ablation seems feasible, we recommend surgery or alternatively other local therapies. Furthermore, we offer detailed recommendations about the management of mitotane treatment and other supportive therapies. Finally, we suggest directions for future research.

Role of Mitotane in Adrenocortical Carcinoma - Review and State of the art

Adrenocortical carcinoma (ACC) is a rare and aggressive endocrine tumour deriving from the adrenal cortex. A correct therapeutic strategy requires a multidisciplinary approach between endocrinologist, surgeon and oncologist. Surgery is the mainstay treatment in ACC while mitotane, deriving from the insecticide dichloro-diphenyl-trichloro-ethane, is the main base of the medical treatment of ACC in consideration of its adrenocytolitic activity. However, the use of mitotane as adjuvant therapy is still controversial, also in consideration of the retrospective nature of several studies. A prospective randomised trial (ADIUVO), recruiting patients with low-intermediate risk of recurrence, is evaluating the utility of adjuvant treatment with mitotane in this setting. The therapeutic response is observed with plasma levels of mitotane >14 mg/L. However, the major difficulty in the management of mitotane treatment is related to side effects and to the risk of toxicity, which is related to plasmatic levels >20 mg/L, that is considered the upper limit of the therapeutic window. Mitotane therapy results in adrenal insufficiency, and glucocorticoid replacement therapy has to be administered at higher doses than those used in other aetiologies of primary adrenal insufficiency. Furthermore, other endocrine side effects related to mitotane should be considered, in particular on thyroid hormone and testosterone metabolism. Waiting for new medical strategies on molecular targets, it will be mandatory to optimise the current knowledge by prospective trials and, in consideration of the rarity of the disease, collaborative studies between endocrinologists and oncologists are necessary.

ATP-binding cassette transporters in progression and clinical outcome of pancreatic cancer: What is the way forward?

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases and is characterized by high chemoresistance, leading to the lack of effective therapeutic approaches and grim prognosis. Despite increasing understanding of the mechanisms of chemoresistance in cancer and the role of ATP-binding cassette (ABC) transporters in this resistance, the therapeutic potential of their pharmacological inhibition has not been successfully exploited yet. In spite of the discovery of potent pharmacological modulators of ABC transporters, the results obtained in clinical trials have been so far disappointing, with high toxicity levels impairing their successful administration to the patients. Critically, although ABC transporters have been mostly studied for their involvement in development of multidrug resistance (MDR), in recent years the contribution of ABC transporters to cancer initiation and progression has emerged as an important area of research, the understanding of which could significantly influence the development of more specific and efficient therapies. In this review, we explore the role of ABC transporters in the development and progression of malignancies, with focus on PDAC. Their established involvement in development of MDR will be also presented. Moreover, an emerging role for ABC transporters as prognostic tools for patients' survival will be discussed, demonstrating the therapeutic potential of ABC transporters in cancer therapy.

Adrenocortical Carcinoma with Hypercortisolism

Adrenocortical carcinoma (ACC) is a rare and aggressive tumor. ACC may be associated with different syndromes of hormone excess, most frequently Cushing's syndrome with or without hypersecretion of androgens. Recent data suggest that cortisol excess is a negative prognostic factor in advanced and localized ACC. Surgery with radical intent, when feasible, is the most effective treatment for ACC with hypercortisolism. Mitotane is the medical treatment of choice, both postoperatively and in inoperable or metastatic cases. Because of its slow onset of action, combination with other antisecretory agents (ie, metyrapone) is helpful to achieve more rapid and effective control of hypercortisolism.

New targeted therapies for adrenocortical carcinomas

Adrenocortical carcinoma (ACC) is a rare malignancy with poor prognosis. It has undergone in-depth clinical and laboratory investigations, with the help of the most important research groups all over the world. Nonetheless the cure for this kind of neoplasia is not right around the corner, given its complexity and multi-faceted feature, that lead researchers to think at "one person one ACC." Currently total resection is the most concrete option for ACC patients, whenever possible. Mitotane remains the main drug for primary or adjuvant therapy, but gives partial and unsatisfactory therapeutic results, especially in metastatic ACC. This prompted the researchers to find other ways to fight against this malignancy: targeted therapy seems the most promising answer, as it is based on biomolecular and genetic cancer signature. Numerous specific targets were explored for the treatment of ACC, such as those involving angiogenesis, steroidogenesis, Wnt/β-catenin pathway and many others key factors. Even if large efforts have been made, no effective target therapy entered in the clinical use. This data should not be considered only as detrimental, rather it should propel scientific research to invest more resources into the therapeutic exploration of ACC and in particular on the most promising strategy, the targeted therapy.

Favorable Response of Metastatic Adrenocortical Carcinoma to Etoposide, Adriamycin and Cisplatin (EAP) Chemotherapy. Report of two Cases

The usefulness of non-specific chemotherapy for advanced adrenocortical carcinoma (ACC) Is controversial. We report on 2 young female patients (25 and 19 yr) who presented with a clinical picture of Cushing's syndrome due to histologically confirmed ACC. The first patient underwent radical surgery, but after a disease-free interval of 6 months a local recurrence was apparent. She was reoperated and treated with 6 courses of cisplatin and etoposide chemotherapy. Mitotane (8 g daily) was begun, but 2 months later debulking surgery was again performed. A second-line chemotherapy with the etoposide, adriamycin, cisplatin (EAP) scheme attained a partial remission lasting 7 months, then metastatic spread to the brain led to death of the patient. The survival time was 30 months. The second patient underwent radical surgery and adjuvant mitotane (4 g daily), but multiple lung and mediastinal metastases were diagnosed after an interval of 29 months. Chemotherapy with the EAP regimen (6 courses) without interrupting mitotane attained a partial remission lasting 21+ months. We suggest that the EAP scheme is active in advanced ACC and that Its association with mitotane is feasible.

New insights and future perspectives in the therapeutic strategy of adrenocortical carcinoma (Review)

Adrenocortical carcinoma (ACC) is a rare endocrine malignancy with an incidence ranging from 0.7 to 2.0 cases/million people per year. Hypercortisolism represents the most common clinical presentation in many patients although, less frequently, some ACC secreting androgens and estrogens are even more pathognomonic compared to cortisol secretion. Currently, radical surgery, when feasible, is still the only curative therapy. Mitotane, an adrenolytic drug, is used in the adjuvant setting and in combination with chemotherapy drugs in metastatic disease. The use of radiotherapy remains controversial, being indicated only in selected cases. New targeted therapies, such as insulin growth factor-1 (IGF-1), mammalian-target of rapamycin (m-TOR), vascular endothelial growth factor (VEGF) inhibitors and others, have recently been investigated with disappointing clinical results. The partial effectiveness of current treatments mandates the need for new therapeutic strategies against this tumor.

The Metastatic Potential and Chemoresistance of Human Pancreatic Cancer Stem Cells

Cancer stem cells (CSCs) typically have the capacity to evade chemotherapy and may be the principal source of metastases. CSCs for human pancreatic ductal carcinoma (PDAC) have been identified, but neither the metastatic potential nor the chemoresistance of these cells has been adequately evaluated. We have addressed these issues by examining side-population (SP) cells isolated from the Panc-1 and BxPC3 lines of human PDAC cells, the oncogenotypes of which differ. SP cells could be isolated from monolayers of Panc-1, but only from spheroids of BxPC3. Using orthotopic xenografts into the severely immunocompromised NSG mouse, we found that SP cells isolated from both cell lines produced tumors that were highly metastatic, in contrast to previous experience with PDAC cell lines. SP cells derived from both cell lines expressed the ABCG2 transporter, which was demonstrably responsible for the SP phenotype. SP cells gave rise to non-SP (NSP) cells in vitro and in vivo, a transition that was apparently due to posttranslational inhibition of the ABCG2 transporter. Twenty-two other lines of PDAC cells also expressed ABCG2. The sensitivity of PDAC SP cells to the vinca alkaloid vincristine could be greatly increased by verapamil, a general inhibitor of transporters. In contrast, verapamil had no effect on the killing of PDAC cells by gemcitabine, the current first-line therapeutic for PDAC. We conclude that the isolation of SP cells can be a convenient and effective tool for the study of PDAC CSCs; that CSCs may be the principal progenitors of metastasis by human PDAC; that the ABCG2 transporter is responsible for the SP phenotype in human PDAC cells, and may be a ubiquitous source of drug-resistance in PDAC, but does not confer resistance to gemcitabine; and that inhibition of ABCG2 might offer a useful adjunct in a therapeutic attack on the CSCs of PDAC.

Molecular Profiling of Refractory Adrenocortical Cancers and Predictive Biomarkers to Therapy

PURPOSE

Current first-line chemotherapy for patients with metastatic adrenocortical cancer (ACC) includes doxorubicin, etoposide, cisplatin, and mitotane with a reported response rate of only 23.2%. New therapeutic leads for patients with refractory tumors are needed; there is no standard second-line treatment.

METHODS

Samples from 135 ACC tumors were analyzed by immunohistochemistry, in situ hybridization (FISH or CISH), and/or gene sequencing at a single commercial reference laboratory (Caris Life Sciences) to identify markers associated with drug sensitivity and resistance.

RESULTS

Overexpression of proteins related to demonstrated chemotherapy sensitivity or resistance included topoisomerase 1, progesterone receptor, and topoisomerase 2-alpha in 46%, 63%, and 42% of cases, respectively. Loss of excision repair cross-complementary group 1 (ERCC1), phosophatase and tensin homolog, O(6)-methylguanine-methyltransferase, and ribonucleotide reductase M1 (RRM1) was identified in 56%, 59%, 71%, and 58% of cases, respectively. Other aberrations included overexpression of programmed death-ligand 1 or programmed cell death protein 1 tumor-infiltrating lymphocytes in >40% of cases. In all, 35% of cases had a mutation in the canonical Wnt signaling pathway (either CTNNB1 or APC) and 48% had a mutation in TP53. No other genomic alterations were identified.

CONCLUSION

Biomarker alterations in ACC may be used to direct therapies, including recommendations for and potential resistance of some patients to traditional chemotherapies, which may explain the low response rate in the unselected population. Limited outcomes data support the use of mitotane and platinum therapies for patients with low levels of the proteins RRM1 and ERCC1.

Developing treatment for adrenocortical carcinoma

Cancer of the adrenal cortex (ACC) is a rare endocrine malignancy with limited treatment options. Patients typically present with autonomous hormonal overproduction and/or a large abdominal mass. Hormonal assays and medical imaging can be diagnostic, but urinary steroid profiling might be a more sensitive technique to assess malignancy in adrenal tumours. The stage of the disease at diagnosis is the most important prognostic factor. The current staging system needs refinement, especially to separate aggressive from indolent disease in stage IV patients and to select patients who need adjuvant treatment after complete surgical resection. Regarding the latter, assessing the proliferation index Ki-67 seems the best tool currently available. Genomic profiling is expected to become of clinical relevance in the future. Medical therapy is centred on the adrenolytic drug mitotane, which carries considerable toxicity and is not easy to manage. Its tolerability and long plasma level build-up phase may be improved by therapeutic drug monitoring based on pharmacokinetic modelling and intensive counselling of patients. Current chemotherapy regimens can offer disease stabilization in about 50% of patients, but an objective response should be expected in <25%. Research on targeted therapy and immunotherapy is difficult in this rare disease with often heavily pre-treated patients and has not yet been successful. Quality of care should be ensured by treating patients in centres with established experience in multidisciplinary oncologic care, who adhere to prevailing guidelines and state-of-the-art in diagnostic and treatment concepts. International collaboration in fundamental research and clinical trials is the key to further elucidate the pathogenesis and to improve patient care.

Effects of adrenolytic mitotane on drug elimination pathways assessed in vitro

Mitotane (1,1-dichloro-2-(o-chlorophenyl)-2-(p-chlorophenyl)ethane, o,p'-DDD) represents one of the most active drugs for the treatment of adrenocortical carcinoma. Its metabolites 1,1-(o,p'-dichlorodiphenyl) acetic acid (=o,p'-DDA) and 1,1-(o,p'-dichlorodiphenyl)-2,2 dichloroethene (=o,p'-DDE) partly contribute to its pharmacological effects. Because mitotane has a narrow therapeutic index and causes pharmacokinetic drug-drug interactions, knowledge about these compounds' effects on drug metabolizing and transporting proteins is crucial. Using quantitative real-time polymerase chain reaction, our study confirmed the strong inducing effects of o,p'-DDD on mRNA expression of cytochrome P450 3A4 (CYP3A4, 30-fold) and demonstrated that other enzymes and transporters are also induced (e.g., CYP1A2, 8.4-fold; ABCG2 (encoding breast resistance cancer protein, BCRP), 4.2-fold; ABCB1 (encoding P-glycoprotein, P-gp) 3.4-fold). P-gp induction was confirmed at the protein level. o,p'-DDE revealed a similar induction profile, however, with less potency and o,p'-DDA had only minor effects. Reporter gene assays clearly confirmed o,p'-DDD to be a PXR activator and for the first time demonstrated that o,p'-DDE and o,p'-DDA also activate PXR albeit with lower potency. Using isolated, recombinant CYP enzymes, o,p'-DDD and o,p'-DDE were shown to strongly inhibit CYP2C19 (IC50 = 0.05 and 0.09 µM). o,p'-DDA exhibited only minor inhibitory effects. In addition, o,p'-DDD, o,p'-DDE, and o,p'-DDA are demonstrated to be neither substrates nor inhibitors of BCRP or P-gp function. In summary, o,p'-DDD and o,p'-DDE might be potential perpetrators in pharmacokinetic drug-drug interactions through induction of drug-metabolizing enzymes or drug transporters and by potent inhibition of CYP2C19. In tumors over-expressing BCRP or P-gp, o,p'-DDD and its metabolites should retain their efficacy due to a lack of substrate characteristics.

The role of ABC transporters in ovarian cancer progression and chemoresistance

Over 80% of ovarian cancer patients develop chemoresistance which results in a lethal course of the disease. A well-established cause of chemoresistance involves the family of ATP-binding cassette transporters, or ABC transporters that transport a wide range of substrates including metabolic products, nutrients, lipids, and drugs across extra- and intra-cellular membranes. Expressions of various ABC transporters, shown to reduce the intracellular accumulation of chemotherapy drugs, are increased following chemotherapy and impact on ovarian cancer survival. Although clinical trials to date using ABC transporter inhibitors have been disappointing, ABC transporter inhibition remains an attractive potential adjuvant to chemotherapy. A greater understanding of their physiological functions and role in ovarian cancer chemoresistance will be important for the development of more effective targeted therapies. This article will review the role of the ABC transporter family in ovarian cancer progression and chemoresistance as well as the clinical attempts used to date to reverse chemoresistance.

Mitotane enhances doxorubicin cytotoxic activity by inhibiting P-gp in human adrenocortical carcinoma cells

Mitotane is currently employed as adjuvant therapy as well as in the medical treatment of adrenocortical carcinoma (ACC), alone or in combination with chemotherapeutic agents. It was previously demonstrated that mitotane potentiates chemotherapeutic drugs cytotoxicity in cancer cells displaying chemoresistance due to P-glycoprotein (P-gp), an efflux pump involved in cancer multidrug resistance. The majority of ACC expresses high levels of P-gp and is highly chemoresistent. The aim of our study was to explore in vitro whether mitotane, at concentrations lower than those currently reached in vivo, may sensitize ACC cells to the cytotoxic effects of doxorubicin and whether this effect is due to a direct action on P-gp. NCI-H295 and SW13 cell lines as well as 4 adrenocortical neoplasia primary cultures were treated with mitotane and doxorubicin, and cell viability was measured by MTT assay. P-gp activity was measured by calcein and P-gp-Glo assays. P-gp expression was evaluated by Western blot. We found that very low mitotane concentrations sensitize ACC cells to the cytotoxic effects of doxorubicin, depending on P-gp expression. In addition, mitotane directly inhibits P-gp detoxifying function, allowing doxorubicin cytotoxic activity. These data provide the basis for the greater efficacy of combination therapy (mitotane plus chemotherapeutic drugs) on ACC patients. Shedding light on mitotane mechanisms of action could result in an improved design of drug therapy for patients with ACC.

Cytotoxic activity of gemcitabine, alone or in combination with mitotane, in adrenocortical carcinoma cell lines

We aimed at investigating in vitro the cytotoxic activity (determined using WST-1, apoptosis and cell cycle assays) of gemcitabine, alone or in combination with mitotane, in mitotane-sensitive H295R and mitotane-insensitive SW-13 cells. Results of these experiments were compared with drug-induced modulation of RRM1 gene, the specific target of gemcitabine. In H295R cells, mitotane and gemcitabine combinations showed antagonistic effects and interfered with the gemcitabine-mediated inhibition of the S phase of the cell cycle. By contrast, in SW-13 cells, except when mitotane was sequentially administered prior to gemcitabine, the combination of the two drugs was synergistic. Such opposite effects were associated with opposite expression profiles of the target gene, with significant up-modulation in H295R but not in SW-13 under gemcitabine and mitotane combination treatment.

Current and emerging therapeutic options in adrenocortical cancer treatment

Adrenocortical carcinoma (ACC) is a very rare endocrine tumour, with variable prognosis, depending on tumour stage and time of diagnosis. The overall survival is five years from detection. Radical surgery is considered the therapy of choice in the first stages of ACC. However postoperative disease-free survival at 5 years is only around 30% and recurrence rates are frequent. o,p'DDD (ortho-, para'-, dichloro-, diphenyl-, dichloroethane, or mitotane), an adrenolytic drug with significant toxicity and unpredictable therapeutic response, is used in the treatment of ACC. Unfortunately, treatment for this aggressive cancer is still ineffective. Over the past years, the growing interest in ACC has contributed to the development of therapeutic strategies in order to contrast the neoplastic spread. In this paper we discuss the most promising therapies which can be used in this endocrine neoplasia.

Immunohistochemical evidence of dysregulation of the mammalian target of rapamycin pathway in primary and metastatic pheochromocytomas

OBJECTIVE

To characterize the status of the mammalian target of rapamycin pathway using formalin-fixed, paraffin-embedded specimens from patients with primary and metastatic pheochromocytoma.

METHODS

Tissue microarrays were built from 19 normal adrenal medullas, 39 primary pheochromocytomas, and 8 unrelated metastatic pheochromocytomas. In 2 of the 8 cases of metastatic pheochromocytoma tissues, samples from the primary tumor were available. The expression levels of phosphatase and tensin homolog, phosphorylated Akt, phosphorylated S6, p27, and c-myc were evaluated by immunohistochemistry.

RESULTS

The levels of phosphatase and tensin homolog and p27 were greater in the nontumor tissue than in the primary and metastatic pheochromocytomas. Increasing levels of phosphorylated Akt were noted in the nontumor adrenal medulla, primary pheochromocytomas, and metastatic pheochromocytomas. Finally, the levels of phosphorylated S6 were greater in the metastatic pheochromocytomas than in the nontumor adrenal medulla and primary pheochromocytomas.

CONCLUSION

We found evidence of dysregulation of the mammalian target of rapamycin pathway in primary and metastatic pheochromocytomas, with increased phosphorylated S6 and phosphorylated Akt, and decreased phosphatase and tensin homolog and p27 expression levels. Because the currently available treatment modalities are less than optimal, our findings lend additional support to continuing to explore the utility of mammalian target of rapamycin pathway-targeted therapy for pheochromocytomas.

Drug interactions with mitotane by induction of CYP3A4 metabolism in the clinical management of adrenocortical carcinoma

Mitotane [1-(2-chlorophenyl)-1-(4-chlorophenyl)-2,2-dichloroethane, (o,p'-DDD)] is the only drug approved for the treatment for adrenocortical carcinoma (ACC) and has also been used for various forms of glucocorticoid excess. Through still largely unknown mechanisms, mitotane inhibits adrenal steroid synthesis and adrenocortical cell proliferation. Mitotane increases hepatic metabolism of cortisol, and an increased replacement dose of glucocorticoids is standard of care during mitotane treatment. Recently, sunitinib, a multityrosine kinase inhibitor (TKI), has been found to be rapidly metabolized by CYP3A4 during mitotane treatment, indicating clinically relevant drug interactions with mitotane. We here summarize the current evidence concerning mitotane-induced changes in hepatic monooxygenase expression, list drugs potentially affected by mitotane-related CYP3A4 induction and suggest alternatives. For example, using standard doses of macrolide antibiotics is unlikely to reach sufficient plasma levels, making fluoroquinolones in many cases a superior choice. Similarly, statins such as simvastatin are metabolized by CYP3A4, whereas others like pravastatin are not. Importantly, in the past, several clinical trials using cytotoxic drugs but also targeted therapies in ACC yielded disappointing results. This lack of antineoplastic activity may be explained in part by insufficient drug exposure owing to enhanced drug metabolism induced by mitotane. Thus, induction of CYP3A4 by mitotane needs to be considered in the design of future clinical trials in ACC.

Malignant pheochromocytoma: predictive factors of malignancy and clinical course in 16 patients at a single tertiary medical center

Metastases appear in approximately 10% of patients with pheochromocytoma. There is no predictive marker of malignancy. The aim is to describe clinical course of patients with malignant pheochromocytoma and to identify predictive features of malignancy. The method involves retrospective analysis of patients files diagnosed with malignant pheochromocytoma at our institution between January 1, 1980 and December 31, 2008. We identified 16 patients with malignant pheochromocytoma. There were more men than women (10/6). Mean age of patients at time of diagnosis was 37.75-year-old. Time of occurrence of metastases ranged from 0 to 22 years after first diagnosis of pheochromocytoma. The mean size of the primary tumor was 12.1 cm. High levels of chromogranin A at the time of diagnosis were associated with the presence of metastases. The pheochromocytoma of the adrenal gland scoring scale (PASS) histological evaluation in adrenal primary tumors was above four in all cases but one. All patients had initial surgery, followed in most cases by palliative therapy: chemotherapy (streptozocin, cyclophosphamide-vincristine-dacarbazine, thalidomide, imatinib, everolimus) or (131)I-MIBG; only the latter had replicable encouraging response evaluation criteria in solid tumor response rates. We observed a 10-year survival rate of 50% after initial diagnosis of pheochromocytoma, and 25% after diagnosis of metastasis. Metastasis can occur very late after the initial diagnosis of pheochromocytoma. High chromogranin A levels may be associated with the presence of metastases and poor prognosis. Histological adrenal PASS higher than 4 appears to be suggestive of malignancy. The best therapeutic approach remains to be established.

Current and emerging therapies for advanced adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare but aggressive malignancy with a poor prognosis. Complete surgical resection offers the only potential for cure; however, even after apparently successful excision, local or metastatic recurrence is frequent. Treatment options for advanced ACC are severely limited. Mitotane is the only recognized adrenolytic therapy available; however, response rates are modest and unpredictable whereas systemic toxicities are significant. Reported responses to conventional cytotoxic chemotherapy have also been disappointing, and the rarity of ACC had hampered the ability to undertake randomized clinical studies until the establishment of the First International Randomized Trial in Locally Advanced and Metastatic Adrenocortical Carcinoma. This yet-to-be reported study seeks to identify the most effective first- and second-line cytotoxic regimens. The past decade has also seen increasing research into the molecular pathogenesis of ACCs, with particular interest in the insulin-like growth factor signaling pathway. The widespread development of small molecule tyrosine kinase inhibitors in broader oncological practice is now allowing for the rational selection of targeted therapies to study in ACC. In this review, we discuss the currently available therapeutic options for patients with advanced ACC and detail the molecular rationale behind, and clinical evidence for, novel and emerging therapies.

Adrenocortical carcinoma

ACC is a rare clinical entity that carries a poor prognosis; early diagnosis and complete surgical resection are associated with the improvement in patient survival. Even with appropriated diagnosis and treatment, most patients will develop recurrence and succumb to ACC because of the underlying tumor biology, the difficulty of achieving a complete resection, and the lack of effective systemic therapies. Despite its many drawbacks, mitotane continues to be a mainstay in the treatment of high-risk patients with ACC, especially those with recurrent or metastatic disease. Recent findings suggest that mitotane, combined with conventional chemotherapeutic agents, may improve survival for such patients.

Long-term disease free survival in a patient with metastatic adreno-cortical carcinoma after complete pathological response to chemotherapy plus mitotane

Adreno-cortical carcinoma (ACC) is a rare cancer with poor prognosis. Complete surgical resection of the primary tumor and, when feasible, of the local and distant metastases offers the best prospects for long-term survival; conversely, the role of systemic therapy in patients developing unresectable metastatic disease is unclear. We describe the case of a young female patient (36 yr) who presented with an androgen-releasing metastatic ACC. Treatment consisted of five courses of chemotherapy with etoposide, doxorubicin and cisplatin (EDP scheme) plus oral mitotane, which caused the complete disappearance of distant metastases and reduction of the primary tumor, as documented by serial computed tomography (CT) scans of the chest and the abdomen. Moreover, during treatment, clinical and biochemical resolution of the hypersecretory status occurred. The left adrenal gland was then removed and histopathological examination showed extensive tumor necrosis and the absence of viable cancer cells. The patient is currently alive without evidence of recurrence 3 yr after surgery. This report shows that chemotherapy plus mitotane could result in complete pathological remission, which may be a surrogate for long-term progression- free survival in metastatic ACC patients.

Clinical review: Adrenocortical carcinoma: clinical update

CONTEXT

Adrenocortical carcinoma (ACC) is a rare and heterogeneous malignancy with incompletely understood pathogenesis and poor prognosis. Patients present with hormone excess (e.g. virilization, Cushing's syndrome) or a local mass effect (median tumor size at diagnosis > 10 cm). This paper reviews current diagnostic and therapeutic strategies in ACC.

EVIDENCE ACQUISITION

Original articles and reviews were identified using a PubMed search strategy (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) covering the time period up until November 2005. The following search terms were used in varying combinations: adrenal, adrenocortical, cancer, carcinoma, tumor, diagnosis, imaging, treatment, radiotherapy, mitotane, cytotoxic, surgery.

EVIDENCE SYNTHESIS

Tumors typically appear inhomogeneous in both computerized tomography and magnetic resonance imaging with necroses and irregular borders and differ from benign adenomas by their low fat content. Hormonal analysis reveals evidence of steroid hormone secretion by the tumor in the majority of cases, even in seemingly hormonally inactive lesions. Histopathology is crucial for the diagnosis of malignancy and may also provide important prognostic information. In stages I-III open surgery by an expert surgeon aiming at an R0 resection is the treatment of choice. Local recurrence is frequent, particularly after violation of the tumor capsule. Surgery also plays a role in local tumor recurrence and metastatic disease. In patients not amenable to surgery, mitotane (alone or in combination with cytotoxic drugs) remains the treatment of choice. Monitoring of drug levels (therapeutic range 14-20 mg/liter) is mandatory for optimum results. In advanced disease, the most promising therapeutic options (etoposide, doxorubicin, cisplatin plus mitotane, and streptozotocin plus mitotane) are currently being compared in an international phase III trial (www.firm-act.org). Adjuvant treatment options after complete tumor removal (e.g. mitotane, radiotherapy) are urgently needed because postoperative disease-free survival at 5 yr is only around 30%, but options have still not been convincingly established. National registries, international cooperations, and trials provide important new structures for patients but also for researchers aiming at systematic and continuous progress in ACC. However, future advances in the management of ACC will mainly depend on a better understanding of the molecular pathogenesis facilitating the use of modern cancer treatments (e.g. tyrosine kinase inhibitors).

Tratamento do tumor do córtex adrenal na infância

O tumor do córtex adrenal (TCA) na infância é raro. Entretanto, no Paraná sua incidência é 15 vezes maior do que a observada em outros países. A mutação germinativa R337H TP53, presente em mais de 95% dos nossos pacientes, provavelmente está relacionada à maior incidência. Cento e vinte e cinco pacientes foram tratados no período de 1966 a 2003. A cirurgia é o único tratamento curativo. Em nossa experiência, tumores no estádio I, ausência de spillage durante a cirurgia e ausência de trombo são parâmetros relacionados à maior sobrevida. Dados preliminares mostram que a associação de etoposídeo, doxorrubicina, cisplatina e mitotano produziu remissão completa do tumor e/ou das metástases em alguns pacientes. Os efeitos colaterais destas drogas são comuns e pode ocorrer insuficiência adrenocortical. As doses de reposição de glicocorticóides e mineralocorticóides devem ser 2 a 3 vezes maiores que as doses fisiológicas.

Biology, clinical characteristics, and management of adrenocortical tumors in children

Childhood adrenocortical tumors (ACT) are very aggressive endocrine neoplasms whose incidence is quite low. Little is known about their pathogenesis, clinical presentation, and optimal treatment. In recent years, however, new information has been derived from the International Pediatric Adrenocortical Tumor Registry (IPACTR), and new clues to its pathogenesis have emerged. To provide an overview of the available data that may apply to pediatric ACT, we reviewed the epidemiology, pathogenesis, and treatment of ACT in adults and in children. Germline TP53 mutation is almost always the predisposing factor in childhood ACT. A unique germline mutation (TP53-R337H) has been described in Southern Brazil, where the incidence of ACT is 10-15 times the general incidence. Childhood ACT typically present during the first 5 years of life and has female predominance. Hormone hyperproduction is almost universal, and most patients present with virilization. Two-thirds of patients have resectable tumors. Surgery is the definitive treatment for ACT, and a curative complete resection should always be attempted. Cisplatin-based chemotherapy with mitotane is indicated for unresectable or metastatic disease, although its impact on overall outcome is slight. In childhood ACT, age, tumor size, and tumor resectability are the most important prognostic indicators. Outcome is stage-dependent; patients with small, resectable tumors have survival rates in excess of 80%, whereas the outcome for patients with unresectable disease is dismal. Patients with large, resectable tumors have an intermediate outcome. Childhood ACT are rare, but their unique epidemiology appear to implicate novel oncogenic pathways that are unique to the pediatric population. Multi-institutional and prospective studies are necessary to further our understanding of the pathogenesis and to improve outcomes.

Andrenocortical carcinomas: twelve-year prospective experience

Adrenocortical carcinoma (AC) is a rare tumor with poor prognosis. Twenty-two patients (14 F, 8 M; age 22 to 59 years; median, 43 years) with AC were evaluated prospectively in a single center: tumor stage was I-II in 12 cases and III-IV in 10. The overall survival in our cohort was 41.6 +/- 42 months; 16 subjects are still alive. Curative surgery was followed by longer survival than debulking or no surgery (p < 0.0001). The first relapse was highly predictive for further recurrences. Recurrent ACs were progressively more aggressive, and they occurred with variable but ever shorter intervals. At diagnosis, 14 patients (63.5%) presented with features of clear adrenocortical hyperactivity. Despite the absence of clinical signs of hormonal excess, all other patients presented some abnormalities of steroid secretion. The most common clinical finding was a recent diagnosis of moderate-to-severe hypertension (68%), poorly controlled by pharmacological treatment, often associated with multiple cardiovascular risk factors. High mitotic rate and undifferentiated polymorph cellular pattern were associated with worse prognosis. Response to treatments other than surgery (mitotane chemotherapy) was better in patients treated early after the first surgery. In conclusion, curative surgery was the most effective treatment. Monitoring arterial pressure, endocrine parameters, and metabolic parameters can be helpful for the early detection of AC recurrences.

Childhood adrenocortical tumours

Childhood adrenocortical tumours (ACT) constitute only about 0.2% of all paediatric malignancies. However, the incidence of ACT varies across geographic regions and is remarkably high in southern Brazil. At presentation, most children show signs and symptoms of virilisation, which may be accompanied by manifestations of the hypersecretion of other adrenal cortical hormones. Fewer than 10% of patients with ACT show no endocrine syndrome at presentation; these are often older children and adolescents. ACT is commonly associated with constitutional genetic abnormalities, particularly mutations of the P53 gene. Histological features are used to classify the tumours as adenomas or carcinomas; however, the distinction between these two subtypes is often difficult. The extent of disease is best evaluated by computed tomography or magnetic resonance imaging; the role of positron-emission tomographic scans has not been defined. Cure of ACT requires complete tumour resection. The role of chemotherapy or radiotherapy has not been established, although definitive responses to several anticancer drugs have been documented. Among patients who undergo complete tumour resection, favourable prognostic factors include age <4 years, smaller tumour size, signs of virilisation alone at presentation, and adenomatous tumour histology. Some children with ACT show abnormalities of growth and development at the time of presentation, but these usually resolve after surgery.

Steroidogenic acute regulatory (StAR)-directed immunotherapy protects against tumor growth of StAR-expressing Sp2-0 cells in a rodent adrenocortical carcinoma model

Adrenocortical carcinoma (ACC) is a highly malignant tumor with poor response to classical antitumor therapy. Steroidogenic acute regulatory (StAR) protein is expressed in most human ACCs. The aim of this study was to induce antitumoral T cells directed against StAR in a murine tumor model. Because a suitable syngenic adrenocortical mouse tumor model is lacking, we established a clone of the mouse myeloma Sp2-0 tumor cell line stably expressing murine StAR (Sp2-mStAR). Using repeated im injections of plasmid DNA encoding mStAR followed by infection with a recombinant vaccinia virus (rVV) expressing mStAR, we induced a cytotoxic T-cell response as measured by enzyme-linked immunospot assay. To demonstrate antitumor activity of the vaccination procedure, mice were treated as follows: group A, mice immunized with plasmids and rVV encoding mStAR receiving Sp2-mStAR cells; control group B, mice immunized with the empty plasmid and the empty rVV receiving Sp2-mStAR cells; control group C, mice immunized with the empty plasmid and rVV encoding P450 side-chain cleavage enzyme receiving Sp2-mStAR cells; and control group D, mice immunized with plasmid and rVV encoding mStAR receiving parental Sp2-0 cells. A high proportion (89-100%) of the control groups B, C, and D developed subcutaneous tumors. In contrast, immunization specific for mStAR (group A) was highly protective against tumor growth (percentage of tumor-free animals, 67%; P < 0.001 vs. controls). In summary, these results show that T-cell tolerance toward mStAR can be broken, resulting in antitumoral immunity. Thus, StAR represents a candidate target antigen for immunotherapeutic strategies against ACC.

Management of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare neoplasm with poor prognosis. Patients present with signs of steroid hormone excess (e.g. Cushing's syndrome, virilization) or an abdominal mass. Tumour size at presentation (mean diameter at diagnosis > 10 cm) is the most important indicator of malignancy. In addition, computed tomography (CT) typically demonstrates an inhomogeneous adrenal lesion with irregular margins and variable enhancement of solid components after intravenous contrast media. Magnetic resonance imaging (MRI) is equally effective as CT and is particularly helpful to visualize invasion into large vessels. Complete tumour removal (R0 resection) offers by far the best chance for long-term survival and therefore surgery is the treatment of choice in stage I-III ACC. Despite tumour resection for cure most patients will eventually develop local recurrence or distant metastases. Thus adjuvant treatment options need to be evaluated in high-risk patients (e.g. radiation therapy of the tumour bed and/or chemotherapy). In tumour recurrence re-operation should always be considered. In metastatic disease (stage IV ACC) not amenable to surgery mitotane (o,p'DDD) remains the first-line therapy. Drug monitoring is needed for effective treatment aiming at concentrations between 14 and 20 mg/l. Patients not responding to mitotane may benefit from cytotoxic chemotherapy (23% partial remissions, 4% complete remissions). Only large prospective multicentre trials comparing different treatment options will allow to make systematic progress in the management of ACC.

A phase II trial of combination chemotherapy and surgical resection for the treatment of metastatic adrenocortical carcinoma: continuous infusion doxorubicin, vincristine, and etoposide with daily mitotane as a P-glycoprotein antagonist

BACKGROUND

Adrenocortical carcinoma (ACC) is rare, nearly always fatal, and to the authors' knowledge has few nonsurgical treatment options. Based on in vitro studies demonstrating the efficacy of mitotane as a P-glycoprotein (Pgp) antagonist, and expression of high levels of Pgp in ACC, the authors conducted a study of infusional doxorubicin, vincristine, and etoposide with oral mitotane +/- surgical resection in patients with metastatic ACC.

METHODS

Thirty-six patients with metastatic ACC received daily oral mitotane (mean, 4.6 g/day) and 96-hour infusional doxorubicin (10 mg/m(2)/day), etoposide (75 mg/m(2)/day), and vincristine (0.4 mg/m(2)/day). Four responding patients (11%) underwent surgery.

RESULTS

Thirty-five patients were evaluable; all had metastatic disease. Eleven patients had not undergone resection of the primary tumor. Approximately 53% of patients had functional tumors. A total of 190 cycles were administered to 36 patients. Responses were observed in 8 patients (22%): 1 complete, 4 partial, and 3 minor responses. The mean duration of response was 12.4 months. Using a landmark method, the median survival of patients who did not respond to chemotherapy was 11.6 months from a point 4 months after the initiation of therapy, whereas that of 8 patients who demonstrated a response to chemotherapy was 34.3 months from that same landmark. High levels of Pgp expression were documented in nine of nine tumors. Mitotane levels > 10 microg/mL, previously shown to antagonize Pgp in vitro, were achieved in 25 of 36 patients (69%). However, rhodamine efflux from CD56-positive cells was not impaired, suggesting poor in vivo Pgp inhibition. The predominant Grade 3/4 toxicity (according to the Common Toxicity Criteria of the National Cancer Institute) was neutropenia in 66% of cycles; however, fever occurred in only 3% of cycles. Daily mitotane was associated with Grade 1/2 nausea, diarrhea, fatigue, and neuropsychiatric changes in 31 of 36 patients (86%).

CONCLUSIONS

Using a combination regimen of daily mitotane with infusional doxorubicin, vincristine, and etoposide in patients with metastatic ACC, responses were observed in 22% of patients. The superiority of this combination over single-agent mitotane is uncertain. The side effects of mitotane made treatment difficult. More effective Pgp antagonists are needed.

Impact of monitoring plasma 1,1-dichlorodiphenildichloroethane (o,p'DDD) levels on the treatment of patients with adrenocortical carcinoma

BACKGROUND

It has been suggested recently that 1,1-dichlorodiphenildichloroethane (o,p'DDD) elicits a dose effect relation in the treatment of patients with adrenocortical carcinoma (ACC). The authors performed a single-center, prospective study with two major objectives: 1) to confirm the interest of plasma o,p'DDD level measurement as a prognostic factor of response to o,p'DDD therapy; and 2) to look for parameters associated with a therapeutic plasma o,p'DDD level, especially the daily o,p'DDD dose.

METHODS

Since 1995, patients with ACC who were referred to the Gustave-Roussy Institute have been enrolled prospectively in the study. Therapy with o,p'DDD was given as first-line therapy in 13 patients with metastatic disease or as adjuvant therapy in 11 patients. Oral o,p'DDD was given in three separate doses up to at least 6-12 g per day together with substitutive adrenal therapy. Plasma o,p'DDD levels were measured using high-performance liquid chromatography every 2 months. The o,p'DDD therapy was monitored to achieve plasma o,p'DDD levels within 14-20 mg/L. World Health Organization criteria were used to evaluate tumor response and toxicity.

RESULTS

Twenty-four patients with ACC were studied, and a plasma o,p'DDD level > 14 mg/L was achieved in 14 patients (58%). An objective tumor response was observed in four patients with metastatic lesions (31%): One was response was complete, and three were objective hormonal responses. These tumor responses were observed among the six patients who achieved therapeutic plasma o,p'DDD levels. In contrast, no response was observed among the seven patients with plasma o,p'DDD levels that remained consistently low. Eight of 11 patients who received o,p'DDD as adjuvant therapy had disease recurrence, although the plasma o,p'DDD level was > 14 mg/L in 6 patients. Grade 3 or 4 neurologic toxicity was observed in three patients (12%), all with an o,p'DDD level > 20 mg/L. The daily o,p'DDD dose was the only parameter associated with the highest plasma o,p'DDD trough levels: It explained 35% of the variability in the plasma o,p'DDD level. A median interval of 3.7 months was found necessary to achieve the highest o,p'DDD trough levels.

CONCLUSIONS

The results confirm the prognostic impact of the plasma o,p'DDD level in patients with metastatic ACC and its interest in avoiding toxicity.

Adrenal cortical carcinoma

Adrenal cortical carcinoma is a rare endocrine tumor, and complete surgical resection is the only potentially curative treatment. Accurate preoperative biochemical and radiographic evaluation of the patient who presents with an adrenal mass optimizes patient management and facilitates a complete margin-negative resection of the primary tumor--the most important prognostic variable for long-term survival. Response to mitotane or chemotherapy is modest in patients with advanced disease. It is hoped that an improved understanding of the molecular pathogenesis of this challenging tumor will lead to the development of novel treatment strategies.

Cytotoxic treatment of adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare, aggressive tumor that is often detected in an advanced stage. Medical treatment with the adrenotoxic drug mitotane has been used for decades, but critical prospective trials on its role in residual disease or as an adjuvant agent after surgical resection are still lacking. The concept of a critical threshold plasma level of the drug must be confirmed in controlled studies. Because individual responsiveness cannot be predicted, the use mitotane is still advised for nonresectable disease. In case of cortisol or other steroid overproduction, several drugs (e.g., ketoconazole or aminoglutethimide) may be used. Chemotherapy with single agents (e.g., doxorubicin or cisplatin) have been disappointing, with low response rates (< 30%) and a short response duration. Part of this refractoriness may be explained by the fact that ACC tumors express the multidrug-resistance gene MDR-1. Chemotherapy with multiple agents has been tested in smaller series and has resulted in significant side effects. The best results were achieved by the combination of etoposide, doxorubicin, and cisplatin associated with mitotane, achieving a response rate of 54%, including individual complete responses. To be able to make progress in treating advanced ACC disease, adjuvant multicenter trials must be encouraged. When mitotane-based therapies are used, monitored drug levels are mandatory.