Today, all human systemic diseases, including cancer and autoimmune pathologies, may be reinterpreted as the consequence of an altered functionless of the cytokine network, with a following enhanced inflammatory status [1-3]. Since most cytokines exert a pro-inflammatory action [1-3], it is difficult to modulate the cytokine network through the administration of the single cytokines, by considering that according to the knowledgements available up to now; only TGF-beta, IL-10, IL-35, and IL-37 (4) have appeared to play a clear anti-inflammatory activity. However, their use in the treatment of human neoplasms is not indicated because of the concomitant immunosuppressive action played by TGF-beta (5), IL-10 (6) and IL-35 [4] on the anticancer immunity, which is mainly mediated by IL-2 [7] and IL-12 [8], and by IL-37 itself [9]. In more detail, IL-2 may play both anti-inflammatory and pro-inflammatory actions, depending on its dose, since low-dose IL-2 has appeared to control the inflammatory status in patients with autoimmune pathologies [10]. In addition, cancer chemotherapy itself has appeared to modulate the cytokine network, and while its effect on the antibacterial immunity is constantly immunosuppressive because of chemotherapy-induced neutropenia, it may play both stimulatory and inhibitory effects on the anticancer immunity, depending on chemotherapy-induced modulation of the cytokine network and its effects on lymphocyte count [11]. Moreover, the recent advances in the area of the Psycho-neuro-endocrine-immunology (PNEI) have demonstrated that the immune system and the cytokine network are physiologically under a neuroendocrine regulation, and in particular it has been shown that the anticancer immunity is inhibited by the opioid agonists, namely the mu-agonists ones [12], whereas it is stimulated by the pineal gland through its most investigated hormone, the indole melatonin (MLT) [13], and other indole and beta-carboline hormones [14], and by the endocannabinoid system [15]. The anticancer activity of both MLT and cannabinoid agents is due to at least three main mechanisms, consisting of direct cytotoxic antiproliferative effect, anti-angiogenic activity, and modulation of the anticancer immunity. In more detail, the stimulatory action on the anticancer immunity played by MLT would mainly depend on a stimulation of IL-2 and IL-12 secretion [13], respectively from Th1 lymphocytes and dendritic cells, while that exerted by the cannabinoid agents would mainly be due to an inhibition of IL-17 secretion [15], which has appeared to directly stimulate cancer cell proliferation [16]. Moreover, the lack of efficacy of cancer therapies could be due at least in part to a concomitant enhanced endogenous secretion of IL-17 [17]. In addition, more recently, ACE2-angiotensin 1-7 (Ang 1-7) axis has appeared to play a fundamental anti-inflammatory anticancer activity [18]. It has also been shown that these three major anti-inflammatory anticancer endogenous systems, including the pineal gland, the endocannabinoid system, and ACE2-Ang 1-7 axis are connected by reciprocal stimulatory effects. In more detail, the pineal MLT has appeared to inhibit ACE expression, and to promote that of ACE2, with a following enhanced production of its enzymatic product, Ang 1-7 [19] expression. Cannabinoids may directly stimulate MLT secretion from the pineal gland [20], and Ang 1-7 would stimulate the expression of cannabinoid receptors [21]. Finally, Ang 1-7 may stimulate the cardiac release of ANP [22], which has also been shown to play an anticancer anti-inflammatory action [23], and to stimulate MLT secretion [24]. In addition, Ang 1-7, as well as cannabinoids, may inhibit IL-17 secretion [15-18], by opposing the inflammatory, pro-thrombotic, and toxic effects of IL-17 on both cardiac and pulmonary functions [25]. As far as the clinical use of cannabinoids is concerned, at present the most clinically investigated cannabinoid agent is cannabidiol (CBD), which has appeared to inhibit cancer cell proliferation [26] and IL-17 secretion [15], and to promote that of IL-12 [27]. The anticancer action of MLT [13-28] and Ang 1-7 [18] has appeared to be a dose-dependent phenomenon [29], while there are controversial data on the dose dependency of the anticancer activity of CBD and other cannabinoid drugs in cancer patients [15], because of their general use for the only palliative therapy rather than to influence cancer growth and progression. Finally, high-dose MLT would amplify the anticancer action of Ang 1-7 [19]. On these bases, a preliminary study was performed to evaluate the possibility to modulate cancer chemotherapy- induced effects on the cytokine network through a neuroendocrine approach consisting of high-dose MLT plus CBD with or without a concomitant administration of low-dose Ang 1-7. This neuroendocrine approach is furtherly justified by the evidence that cancer progression has appeared to be associated with a concomitant progressive decline in the pineal function [13] and endocannabinoid system [15].  

The study included 100 consecutive patients, who underwent chemotherapy for locally advanced or metastatic solid neoplasm, whose clinical characteristics are reported in (Table 1).

Table 1: Clinical characteristics of cancer patients treated by chemotherapy (CT) alone, CT plus melatonin (MLT) and cannabidiol (CBD), or CT with MLT plus CBD and angiotensin 1-7 (Ang 1-7).

Most patients had been previously treated by a first line of chemotherapy. Moreover, as shown in (Table 2).

Table 2: Characteristics of Cancer Patients Treated By Chemotherapy (CT) Alone, CT plus High-Dose Melatonin (MLT) and Cannabidiol (CBD) or CT plus MLT and CBD plus Angiotensin 1-7 (Ang 1-7).

According to the standard guide-lines, the chemotherapeutic regimen consisted of oxaliplatin plus 5-fluorouracil in colorectal and gastric tumours, cisplatin plus pemetrexed in non-small cell lung cancer, epirubicin plus cyclophosphamide in the common breast cancer, eribulin in triple negative breast cancer, abraxane plus gemcitabine or 5-fluorouracil, irinotecan and oxaliplatin (FOLFIRINOX) in pancreatic cancer, carboplatin plus taxol in gynaecologic tumours, ifosfamide in soft tissue sarcomas, and temozolomide in brain glioblastoma. After the approval of the Ethical Committee, the clinical protocol was explained to each patient, and written consent was obtained. Eligibility criteria were, as follows: histologically proven solid tumour, measurable lesions, no double tumour, and no more than one previous chemotherapeutic line. According to tumour histotype and type of chemotherapy, patients were randomized to receive chemotherapy alone, chemotherapy plus high-dose MLT and CBD, or chemotherapy plus MLT, CBD and low-dose Ang 1-7. All neuroendocrine agents were administered orally. MLT was given at a dose of 100 mg/day during the dark period of the day according to its physiological circadian rhythm [13], CBD was given at 10 mg twice/day (8 AM and 8 PM), and Ang 1-7 was given at 0.5 mg/day in the morning, by controlling blood pressure because of its potential hypotensive effect. The immune response was assessed by evaluating changes in lymphocyte-to-monocyte ratio (LMR) because of its fundamental prognostic significance to predict the efficacy of chemotherapy itself [30], by considering its pre-treatment values in comparison to those observed after 3 chemotherapeutic cycles, and by correlating the results to the radiologically evaluated clinical response. Normal values of LMR observed in our laboratory (95% confidence limits) were greater than 2.1. The clinical response was assessed according to WHO criteria after three chemotherapeutic cycles by repeating the radiological examinations, including CT scan, NMR, and PET. The results were statistically evaluated by the chi-square test and the Student’s t test, as appropriate.

As shown in Table 1, patients were well balanced for all main prognostic variables, including tumor histotypes, disease extension, and previous chemotherapeutic lines. The clinical results are reported in (Table 3).

Table 3:  Clinical Response (WHO Criteria) To Chemotherapy (CT) Alone, CT Plus The Pineal Hormone Melatonin (MLT) And Cannabidiol (CBD), Or CT + MLT + CBD + Angiotensin 1-7 (Ang 1-7) In Cancer Patients.

As shown, the percentage of complete response (CR) achieved in patients concomitantly treated with MLT, CBD and Ang 1-7, was significantly higher with respect to that obtained in patients treated by the only chemotherapy (P<0.001) or chemotherapy plus MLT and CBD (P<0.05). On the same way, the percentage of objective tumour regressions, including CR and partial response (PR), observed in patients concomitantly treated with MLT, CBD and Ang 1-7, was significantly higher than that found in patients receiving the only chemotherapy (P<0.001) or chemotherapy plus MLT and CBD (P<0.05), whose efficacy, however, was significantly higher than that found in patients treated by the only chemotherapy (P<0.05). Finally, the percentage of disease control, including CR, PR, and stable disease (SD), observed in patients treated by chemotherapy plus MLT, CBD and Ang 1-7was significantly higher than that observed in patients, who received the only chemotherapy (P<0.001) or chemotherapy plus MLT and CBD (P<0.05). The percentage of CR obtained through the concomitant administration of Ang 1-7 was particularly evident in the case of glioblastoma (3/5) (67%) with respect to chemotherapy alone (0/4) or chemotherapy plus MLT and CBD (1/4) (25%). Both neuroendocrine regimens were well tolerated, and most patients referred an improvement in mood, anxiety, and quality of sleep. The main hematologic effect was the control of thrombocytopenia through both regimens, since the percentage of thrombocytopenia observed in both groups concomitantly treated with MLT and CBD alone (3/34, 9%) or in association with Ang 1-7 (2/33, 6%) was significantly lower with respect to that occurring in patients, who received the only chemotherapy (8/33 (24%), P<0.05). Finally, the percentage of asthenia observed in patients concomitantly treated under chemotherapy by Ang 1-7 was significantly lower with respect to that occurring in both patients treated with chemotherapy alone or chemotherapy in association with MLT and CBD (2/33 (6%) vs 12/33 (36%) vs 8/34 (21%), P<0.01 and P<0.05). (Table 4).

Table 4:  Lymphocyte-To-Monocyte Ratio (LMR) Mean Values (Mean +/- SE) In 100 Advanced Cancer Patients Before And After Chemotherapy In Relation To The Clinical Response: Clinical Response (CR), Partial Response (PR), Stable Disease (SD) And Progressive Disease (PD).

Shows changes in LMR mean values in relation to the clinical response. Before treatment, abnormally low values of LMR were seen in 36% of patients. Irrespectively of the type of treatment, patients with CR or PR showed a significant increase in LMR mean values (P<0.05). Moreover, LMR mean values increased also in patients with SD, event though not in a significant manner, whereas they significantly decreased in patients, who had a progressive disease (P<0.05).

In addition to previous results, which had already shown the possibility to enhance chemotherapy efficacy by high-dose MLT (13,29), this preliminary study would suggest that better results may be furtherly achieved by the concomitant administration of another endogenous molecule also provided by antitumor immunomodulating activity, such as Ang 1-7. In more detail, the concomitant administration of Ang 1-7 would increase the percentage of complete tumor regressions, and this result is particularly important by considering that most patients were already pre-treated by chemotherapy. Moreover, this study would confirm the specific efficacy of Ang 1-7 in the treatment of cancer- and cancer chemotherapy-induced asthenia, already observed in experimental conditions [18]. Obviously, the relatively low number of patients, and the different tumor histotypes and chemotherapeutic regimens do not allow to draw define conclusions in relation to each single cancer histotype cancer and chemotherapy regimen. Moreover, longitudinal studies will be needed to evaluate the impact of the different treatments on the survival time. In any case, this study furtherly confirms the importance of the clinical investigation of the neuroendocrine status of cancer patients, since some cancer-related immune alterations could simply represent the consequence of an altered neuroendocrine regulation of the cytokine network, whose correction could enhance the control of the neoplastic progression, as shown by the present study. Since Ang 1-7 has been employed at low-doses with respect to those previously reported in the literature[18], this evidence would furtherly confirm that MLT may enhance the activation of ACE2-Ang 1-7-Mas receptor axis [19]. Therefore, CBD, Ang 1-7 and MLT (CAM regimen) would not simply represent an effective empiric combination of different agents, but it consists of a neuroendocrine schedule able to correct the main cancer progression-related neuroendocrine deficiencies, including the pineal endocrine function, the endocannabinoid system, and ACE2-Ang 1-7 axis. The increase in LMR in cancer patients with objective tumor regression would demonstrate the involvement of the antitumor immune response in chemotherapy-induced tumor destruction. Unfortunately, cancer chemotherapy is generally interpreted only to destroy cancer cells, rather than also to consider its effect on the cytokine network and its consequent influence on the antitumor immunity in possible different ways, as already demonstrated since many years in experimental conditions [11]. Then, it is the time to reconsider cancer chemotherapy as a potential immunomodulating strategy to influence the immune status of cancer patients.The association between chemotherapy and neuroimmune regimens is also justified by the fact that the efficacy of the antitumor immunity is higher in the presence of a reduced number of cancer cells [8-9, 13], which is the aim of cancer chemotherapy. Furter studies, however, by evaluating changes in the blood levels of the main pro-tumoral inflammatory cytokines, namely IL-17 itself, will be required to establish whether the increased efficacy of chemotherapy induced by the neuroendocrine regimen with MLT, CBD and Ang 1-7 may be due to a modulation of the immunoinflammatory response of cancer patients in an antitumor way.Moreover, further studies will be required to establish the effect of cannabinoid agents other than CBD, including cannabidiol and cannabigerol. In conclusion, this study clinically confirms previous experimental evidences [13-15,18], showing the possibility to modulate the antitumor immunity by a neuroimmune strategy, in an attempt to control the cytokine network in an antitumor way, and to enhance the efficacy of cancer chemotherapy, as well as to improve its safety.

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