A randomised trial of MACC chemotherapy with or without lonidamine in advanced non-small cell lung cancer. Cuneo Lung Cancer Study Group (CuLCaSG)

The Effect of Oxidative Phosphorylation on Cancer Drug Resistance

Recent studies have shown that oxidative phosphorylation (OXPHOS) is a target for the effective attenuation of cancer drug resistance. OXPHOS inhibitors can improve treatment responses to anticancer therapy in certain cancers, such as melanomas, lymphomas, colon cancers, leukemias and pancreatic ductal adenocarcinoma (PDAC). However, the effect of OXPHOS on cancer drug resistance is complex and associated with cell types in the tumor microenvironment (TME). Cancer cells universally promote OXPHOS activity through the activation of various signaling pathways, and this activity is required for resistance to cancer therapy. Resistant cancer cells are prevalent among cancer stem cells (CSCs), for which the main metabolic phenotype is increased OXPHOS. CSCs depend on OXPHOS to survive targeting by anticancer drugs and can be selectively eradicated by OXPHOS inhibitors. In contrast to that in cancer cells, mitochondrial OXPHOS is significantly downregulated in tumor-infiltrating T cells, impairing antitumor immunity. In this review, we summarize novel research showing the effect of OXPHOS on cancer drug resistance, thereby explaining how this metabolic process plays a dual role in cancer progression. We highlight the underlying mechanisms of metabolic reprogramming in cancer cells, as it is vital for discovering new drug targets.

Effect of Differences in Metabolic Activity of Melanoma Models on Response to Lonidamine plus Doxorubicin

Lonidamine (LND), a metabolic modulator, sensitizes DB-1 human melanoma to doxorubicin (DOX) chemotherapy by acidifying and de-energizing the tumor. This report compares the effects of LND on two human melanoma lines, DB-1 and WM983B, which exhibit different metabolic properties. Using liquid chromatography mass spectrometry and Seahorse analysis, we show that DB-1 was more glycolytic than WM983B in vitro. ³¹P magnetic resonance spectroscopy (MRS) indicates that LND (100 mg/kg, i.p.) induces similar selective acidification and de-energization of WM983B xenografts in immunosuppressed mice. Over three hours, intracellular pH (pHi) of WM983B decreased from 6.91 ± 0.03 to 6.59 ± 0.10 (p = 0.03), whereas extracellular pH (pHe) of this tumor changed from 7.03 ± 0.05 to 6.89 ± 0.06 (p = 0.19). A decline in bioenergetics (β-NTP/Pi) of 55 ± 5.0% (p = 0.03) accompanied the decline in pHi of WM983B. Using ¹H MRS with a selective multiquantum pulse sequence and Hadamard localization, we show that LND induced a significant increase in tumor lactate levels (p < 0.01). LND pre-treatment followed by DOX (10 mg/kg, i.v.) produced a growth delay of 13.7 days in WM983B (p < 0.01 versus control), a growth delay significantly smaller than the 25.4 days that occurred with DB-1 (p = 0.03 versus WM983B). Differences in relative levels of glycolysis may produce differential therapeutic responses of DB-1 and WM983B melanomas.

Mechanism of antineoplastic activity of lonidamine

Lonidamine (LND) was initially introduced as an antispermatogenic agent. It was later found to have anticancer activity sensitizing tumors to chemo-, radio-, and photodynamic-therapy and hyperthermia. Although the mechanism of action remained unclear, LND treatment has been known to target metabolic pathways in cancer cells. It has been reported to alter the bioenergetics of tumor cells by inhibiting glycolysis and mitochondrial respiration, while indirect evidence suggested that it also inhibited l-lactic acid efflux from cells mediated by members of the proton-linked monocarboxylate transporter (MCT) family and also pyruvate uptake into the mitochondria by the mitochondrial pyruvate carrier (MPC). Recent studies have demonstrated that LND potently inhibits MPC activity in isolated rat liver mitochondria (K_i 2.5μM) and cooperatively inhibits l-lactate transport by MCT1, MCT2 and MCT4 expressed in Xenopus laevis oocytes with K_0.5 and Hill coefficient values of 36-40μM and 1.65-1.85, respectively. In rat heart mitochondria LND inhibited the MPC with similar potency and uncoupled oxidation of pyruvate was inhibited more effectively (IC₅₀~7μM) than other substrates including glutamate (IC₅₀~20μM). LND inhibits the succinate-ubiquinone reductase activity of respiratory Complex II without fully blocking succinate dehydrogenase activity. LND also induces cellular reactive oxygen species through Complex II and has been reported to promote cell death by suppression of the pentose phosphate pathway, which resulted in inhibition of NADPH and glutathione generation. We conclude that MPC inhibition is the most sensitive anti-tumour target for LND, with additional inhibitory effects on MCT-mediated l-lactic acid efflux, Complex II and glutamine/glutamate oxidation.

Reviving Lonidamine and 6-Diazo-5-oxo-L-norleucine to Be Used in Combination for Metabolic Cancer Therapy

Abnormal metabolism is another cancer hallmark. The two most characterized altered metabolic pathways are high rates of glycolysis and glutaminolysis, which are natural targets for cancer therapy. Currently, a number of newer compounds to block glycolysis and glutaminolysis are being developed; nevertheless, lonidamine and 6-diazo-5-oxo-L-norleucine (DON) are two old drugs well characterized as inhibitors of glycolysis and glutaminolysis, respectively, whose clinical development was abandoned years ago when the importance of cancer metabolism was not fully appreciated and clinical trial methodology was less developed. In this review, a PubMed search using the words lonidamine and 6-diazo-5-oxo-L-norleucine (DON) was undertaken to analyse existing information on the preclinical and clinical studies of these drugs for cancer treatment. Data show that they exhibit antitumor effects; besides there is also the suggestion that they are synergistic. We conclude that lonidamine and DON are safe and potentially effective drugs that need to be reevaluated in combination as metabolic therapy of cancer.

Lonidamine induces intracellular tumor acidification and ATP depletion in breast, prostate and ovarian cancer xenografts and potentiates response to doxorubicin

We demonstrate that the effects of lonidamine (LND, 100 mg/kg, i.p.) are similar for a number of xenograft models of human cancer including DB-1 melanoma and HCC1806 breast, BT-474 breast, LNCaP prostate and A2870 ovarian carcinomas. Following treatment with LND, each of these tumors exhibits a rapid decrease in intracellular pH, a small decrease in extracellular pH, a concomitant monotonic decrease in nucleoside triphosphate and an increase in inorganic phosphate over a 2-3 h period. We have previously demonstrated that selective intracellular tumor acidification potentiates response of this melanoma model to melphalan (7.5 mg/kg, i.v.), producing an estimated 89% cell kill based on tumor growth delay analysis. We now show that, in both DB-1 melanoma and HCC1806 breast carcinoma, LND potentiates response to doxorubicin, producing 95% cell kill in DB-1 melanoma at 7.5 mg/kg, i.v. doxorubicin and 98% cell kill at 10.0 mg/kg doxorubicin, and producing a 95% cell kill in HCC1806 breast carcinoma at 12.0 mg/kg doxorubicin. Potentiation of doxorubicin may result from cation trapping of the weakly basic anthracycline. Recent experience with the clinical treatment of melanoma and other forms of human cancer suggests that these diseases will probably not be cured by a single therapeutic procedure other than surgery. A multimodality therapeutic approach will be required. As a potent modulator of tumor response to N-mustards and anthracyclines as well as tumor thermo- and radiosensitivity, LND promises to play an important clinical role in the management and possible complete local control of a number of prevalent forms of human cancer.

Prognostic value of stage grouping and TNM descriptors in lung cancer

STUDY OBJECTIVES

The International Staging System for Lung Cancer (ISSLC) was revised in 1997. Validation studies are numerous but include only selected surgical patients. This study aims to verify the following: (1) the reliability of the ISSLC in an unselected lung cancer population; (2) the likely improvement in prognostic capability of the new classification; and (3) the possibilities for further improvements.

DESIGN

Analysis of a single institution database over a 16-year period from 1983 to 1998.

SETTING

Community-based hospital and second referral level institution for a province of 500,000 people.

PATIENTS

The study included 1,296 consecutive patients (1,117 men), with pathologically documented lung cancer (46% with squamous cell cancer), staged both clinically (77%) and pathologically (23%), and treated, for the most part, with chemotherapy (52%).

INTERVENTIONS

Anthropometric, clinical, and laboratory data were recorded prospectively. Survival analysis was performed by the Kaplan-Meier method and Cox multivariate regression analysis.

MEASUREMENT AND RESULTS

The 1997 revised ISSLC classification fit well with the cohort studied. Each stage and substage significantly differed from each other, except for stage IIA. In this stratum, there were only 13 patients. Comparing the 1986 and the 1997 classifications, no substantial differences were observed (log-rank statistics, 295 vs 293, respectively; p < 0.0001). Independent of the classification used, the Cox models were always highly predictive of the outcome. The only way to increase their efficiency was to replace the variable stage with the original TNM descriptors.

CONCLUSIONS

Since grouping different TNM subsets into one stage is not really helpful, we might choose to use TNM descriptors in clinical practice and in research.

A survey of the ethical considerations in randomised trials for lung cancer

BACKGROUND

In order to promote a more productive debate on the ethics of randomised clinical trials (RCTs), we present a survey on the ethical aspects of published RCTs for lung cancer.

METHODS

Data from 92 published reports of RCTs for lung cancer, as identified from the Cancerlit 1993-1995 database were supplemented by a questionnaire mailed to the authors of those publications. The analysis focused on respect of autonomy, non-maleficence, beneficence, and justice as the ethical principles applicable to society, patients in trials, patients not included in RCTs and physicians. ETHICAL ANALYSIS: The benefits to society include an objective evaluation of new treatments. The principle of autonomy was often violated for patients who were inadequately informed about the disease or about RCT. In some trials with prolonged recruitment, the principle of non-maleficence was not fully respected since patients continued to be randomised in spite of an obvious advantage of one of the treatments. When compared to those not included in a trial, patients in RCTs were reported to benefit from more precise standards, superior quality assurance of diagnostic and therapeutic procedures, more attention from the physician, easier appointments and easier access to hospitalisation. However, these benefits diminish patients' autonomy and lead to injustice towards patients not included in the trials. While benefits to physicians were usually modest and in proportion to their contribution, an influence upon their autonomy cannot be excluded.

CONCLUSION

More attention to the aforementioned ethical caveats of RCTs should alleviate the ethical costs and might also bring more patients into future trials.

Treatment of advanced (stages III and IV) non-small-cell lung cancer

Lung cancer is the leading cause of cancer deaths, and approximately 85% of patients in whom this neoplasm is diagnosed will die of this disease as a result of micrometastatic disease from tumors that appeared surgically resectable or of surgically unresectable disease that is either locally advanced or metastatic. It will affect approximately 171,000 people in the United States in 1998 and about 75% of these cases will be non-small-cell lung cancer (NSCLC). In only 25% of cases can complete surgical resection and cure be considered. Despite this grim outlook, advances have recently been made that beckon in an era of cautious optimism. In this review, a discussion of the latest developments in the management of locally advanced and metastatic NSCLC will be presented in detail. One of the significant developments has been the modifications to the staging system after the natural history of various stages was better characterized by reviewing the outcome of more than 5000 patients. Advances have also been seen in the diagnostic field. Specifically, positron emission tomography and endoscopic ultrasonography and biopsy are being evaluated to determine their role in diagnosing and staging lung cancer. At the present, however, history and physical examination, serum evaluation, computed tomography, and conventional approaches for obtaining a histologic diagnosis are standard practice. The role of adjuvant therapy, both postoperatively and in the neoadjuvant setting, has been studied. There are no data to support the use of radiotherapy or chemotherapy, with or without radiotherapy, in the postoperative setting. In the neoadjuvant setting, some intriguing results in favor of adjuvant chemotherapy have been observed. As discussed in detail these results provide preliminary data and need to be evaluated on a larger scale. Before the 1990s radiotherapy was the principal treatment modality used in the treatment of patients with locally advanced NSCLC. However, the results of several studies have shown the superiority of chemotherapy and radiotherapy in combination for patients with unresectable stage III NSCLC. Many questions regarding the optimal modes of chemotherapy and radiotherapy and the timing of these two modalities have yet to be answered. Concurrent with these advances has been the development of new chemotherapeutic agents that have been extensively evaluated in phase I and II trials. These agents include gemcitabine, paclitaxel, docetaxel, vinorelbine, and irinotecan. These agents have shown significant activity and acceptable toxicity when used in combination with cisplatin or carboplatin, but the results from the large cooperative trials that are ongoing are eagerly awaited to help define the optimal regimen. Further studies are either planned or ongoing to further define the role of these newer agents in the treatment of metastatic disease, in combination with radiotherapy for unresectable disease, and in the surgical adjuvant setting.

Efficacy of platinum-based regimens in non-small cell lung cancer. A negative report from the Cuneo Lung Cancer Study Group

Combination chemotherapy with cytotoxic agents is the regular treatment for patients with advanced non-small cell lung cancer (NSCLC), good performance status, and no major clinical contraindications. Since the early 1980s, platinum-based chemotherapy is the cornerstone of this treatment, while combinations containing long-acting alkylating agents have been nearly abandoned, and represent a sort of historical treatment. Nevertheless, the real survival benefits of cisplatin are uncertain and still debated. To attempt an answer, the Cuneo Lung Cancer Study Group (CuLCaSG) carried out a clinical trial comparing a platinum (MVP) versus a non-platinum-based combination chemotherapy (MACC). The study comprised 156 patients with advanced NSCLC randomly assigned to the two treatment arms. MACC and MVP chemotherapies were given as originally described and continued until progression of disease, unacceptable toxicity, or refusal by the patient. For a medium of four cycles of MVP and three cycles of MACC, the median dose intensity (DI) reached was, respectively, 95% and 100% of the intended (P = 0.0132). In all, 27 objective responses (1 complete and 16 partial responses in patients allocated to MVP versus 10 partial responses of the MACC group) were observed. Median progression-free and global survivals were, respectively, 21 and 34 weeks for MVP and 20 and 31 weeks for MACC (non-significant differences). The treatment plan was found non-significant also multivariate analysis of survival. Toxicity was rather similar in the two arms, except for more severe neurological toxicity, anemia, thrombocytopenia, nausea, and vomiting in patients on MVP. Alopecia was more common after MACC. Subjective tolerance to treatment, and perception of physical and psychological well-being were rated similarly by patients of both groups. In conclusion, MVP was moderately more active than MACC, and showed a foreseeable and reversible toxicity, of a low-medium grade. However, this CuLCaSG study failed to substantiate any survival benefit from the use of platinum in combination with other cytotoxic agents.

Cisplatin, epirubicin, and vindesine with or without lonidamine in the treatment of inoperable nonsmall cell lung carcinoma: a multicenter randomized clinical trial

BACKGROUND

Lonidamine (LND) is an indazol-carboxylic acid derivative that selectively inhibits the energy metabolism of neoplastic cells, and increases the permeability of cell membranes. In vitro studies have demonstrated that LND can potentiate the oncolytic activity of cytotoxic drugs and is able to reverse the acquired multidrug resistance of neoplastic cells. Some clinical trials have suggested a synergism of LND with alkylating agents, cisplatin, and anthracyclines in various solid tumors.

METHODS

From June 1990 to June 1993, 158 previously untreated patients with Stage IIIB and IV nonsmall cell lung cancer (NSCLC) were enrolled into a multicentric randomized trial to evaluate the addition of LND to a cisplatin-epirubicin-vindesine regimen. Eighty patients in the control arm (A) received cisplatin, 60 mg/m2 intravenously (i.v.); epirubicin, 60 mg/m2 i.v.; and vindesine, 3 mg/m2 i.v. (PEV), on Day 1 every 4 weeks, whereas 78 patients in the experimental arm (B) received the same regimen with the addition of LND from 75 mg orally three times on Day 1 to 150 mg orally three times on Day 7+ until tumor progression occurred.

RESULTS

The experimental treatment achieved a significantly higher proportion of major responses in comparison with the control regimen (43% vs. 24%; P=0.02). The addition of LND apparently potentiated the activity of this cytotoxic treatment, particularly in patients with metastatic disease (overall response rate, 39% vs. 17%). The median time to progression (5 vs. 8 months; P=0.0007) and the median survival time (7.6 vs. 11 months; P=0.0013) were also statistically improved in Arm B. The acute toxicity of the 2 treatments was low: only 6% of patients in Arm A and 4% of patients in Arm B had to withdraw from treatment due to Grade 4 World Health Organization toxicity. The main additional side effects related to the administration of LND were epigastralgia, myalgia, asthenia, and orchialgia. However, these symptoms were mild and controlled by the concomitant administration of low doses of steroids.

CONCLUSIONS

The mild acute toxicity of the PEV regimen and the acceptable and nonoverlapping additional side effects of LND render our experimental therapy worthy of consideration for the management of NSCLC patients with poor performance status or low tolerance to more aggressive therapeutic approaches.

Karnofsky and ECOG performance status scoring in lung cancer: a prospective, longitudinal study of 536 patients from a single institution

The Karnofsky's index of performance status (KPS) and the Eastern Cooperative Oncology Group Performance Status Scale (ECOG PS) are widely used methods of assessing the functional status of cancer patients. In this study, we compare their predictive validity, and suggest a table of transformation between scales. 536 consecutive lung cancer patients were assigned both KPS and ECOG PS scores before, during and after treatment (in all, 1656 assignments). Patients were accurately staged at diagnosis, and carefully re-evaluated at each follow-up visit. Multiple clinical, laboratory and instrumental data were recorded along with performance status assessments. Survival times were measured from the pathological diagnosis. KPS and ECOG PS assignments were strongly related to each other (Spearman R = -0.869). Correlation between scales persisted unchanged in pretreatment and post-treatment assessments, advanced and limited diseases, response or non-response to treatment, and different assessors (R indices ranging from -0.825 to -0.901). A three-point conversion table showed the highest rate of success with an overall percentage of agreement exceeding 84% (grade 1: KPS = 100, 90, 80 and ECOG PS = 0, 1; grade 2: KPS = 70, 60 and ECOG PS = 2; grade 3: KPS < 60 and ECOG PS = 3, 4). Both univariate and multivariate analyses of survival documented the predictive validity of the two scales. However, KPS showed less ability than ECOG PS to discriminate patients with different prognosis. Because of the better predictive ability shown in this study, ECOG PS should be preferred to KPS. A general consensus on the scale to use could avoid problems of conversion, which is not always easy and free of errors.