Melatonin has favorable preventive effects on experimental chronic pancreatitis rat model

An overview of the relationship between melatonin and drug resistance in cancers

The most common methods of treating cancer are surgery, chemotherapy, and radiotherapy. However, given that some cancers are not operable, the best method is chemotherapy and radiotherapy. Over time, people become resistant to chemotherapy drugs, and increasing the dose of the drug leads to damage to normal cells. In this article, various sources such as Google Scholar, PubMed, and Semantic Scholar were used, and articles between 1997 and 2025 that were relevant to our topic were selected. Various factors are involved in drug resistance. Melatonin is a hormone that has various roles in the body. One of its most important functions is regulating the circadian rhythm of sleep and its anti-inflammatory and antioxidant properties. According to studies, melatonin plays a role in the treatment of some diseases and cancers. The roles of melatonin in cancer treatment include anti-apoptotic, anti-angiogenic, and anti-migratory effects, as well as drug resistance and cell cycle regulation. As mentioned, one of the main reasons for the failure of cancer treatment is drug resistance, and the role of melatonin in drug resistance in cancers has been proven. Therefore, in this study, our goal is to investigate the mechanisms through which melatonin plays a role in drug resistance in different types of cancer.

Practical application of melatonin for pancreas disorders: protective roles against inflammation, malignancy, and dysfunctions

Melatonin, a hormone primarily produced by the pineal gland, exhibits a range of physiological functions that extend beyond its well-known role in regulating circadian rhythms. This hormone influences energy metabolism, modulates insulin sensitivity, and plays a significant role in controlling sleep patterns and food intake. Notably, melatonin is also synthesized in various peripheral organs, including the gastrointestinal system and pancreas, suggesting its function as a local hormone. The presence of melatonin receptors in the pancreas underscores its relevance in pancreatic physiology. Pancreatic disorders, such as diabetes mellitus (DM), pancreatitis, and pancreatic cancer, often stem from inflammatory processes. The majority of these conditions are characterized by dysregulated immune responses and oxidative stress. Melatonin's anti-inflammatory properties are mediated through the inhibition of pro-inflammatory cytokines and the activation of antioxidant enzymes, which help to mitigate cellular damage. Furthermore, melatonin has demonstrated pro-apoptotic effects on cancer cells, promoting cell death in malignant tissues while preserving healthy cells. Thus, melatonin emerges as a multifaceted agent with significant therapeutic potential for pancreatic disorders. Its ability to reduce inflammation and oxidative stress positions it as a promising adjunct therapy for conditions such as diabetes mellitus, pancreatitis, and pancreatic cancer. By modulating immune responses and enhancing cellular resilience through antioxidant mechanisms, melatonin not only addresses the symptoms but also targets the underlying pathophysiological processes associated with these disorders. This review aims to categorize and summarize the impacts of melatonin on pancreatic functions and disorders, emphasizing its potential as a therapeutic agent for managing pancreatic dysfunctions. Future research should focus on elucidating the precise mechanisms by which melatonin exerts its protective effects on pancreatic tissues and exploring optimal dosing strategies for clinical applications. The integration of melatonin into treatment regimens may enhance existing therapies and offer new hope for individuals suffering from pancreatic dysfunctions.

Melatonin regulates endoplasmic reticulum stress in diverse pathophysiological contexts: A comprehensive mechanistic review

The endoplasmic reticulum (ER) is crucial for protein quality control, and disruptions in its function can lead to various diseases. ER stress triggers an adaptive response called the unfolded protein response (UPR), which can either restore cellular homeostasis or induce cell death. Melatonin, a safe and multifunctional compound, shows promise in controlling ER stress and could be a valuable therapeutic agent for managing the UPR. By regulating ER and mitochondrial functions, melatonin helps maintain cellular homeostasis via reduction of oxidative stress, inflammation, and apoptosis. Melatonin can directly or indirectly interfere with ER-associated sensors and downstream targets of the UPR, impacting cell death, autophagy, inflammation, molecular repair, among others. Crucially, this review explores the mechanistic role of melatonin on ER stress in various diseases including liver damage, neurodegeneration, reproductive disorders, pulmonary disease, cardiomyopathy, insulin resistance, renal dysfunction, and cancer. Interestingly, while it alleviates the burden of ER stress in most pathological contexts, it can paradoxically stimulate ER stress in cancer cells, highlighting its intricate involvement in cellular homeostasis. With numerous successful studies using in vivo and in vitro models, the continuation of clinical trials is imperative to fully explore melatonin's therapeutic potential in these conditions.

Certolizumab Has Favorable Efficacy on Preventing Pancreas and Target Organs Damage in Acute Pancreatitis

OBJECTIVE

It was targeted to assess the efficacy of certolizumab on pancreas and target organs via biochemical parameters and histopathologic scores in experimental acute pancreatitis (AP).

MATERIALS AND METHODS

Forty male Sprague Dawley rats were divided into the following 5 equal groups: group 1 (sham group), group 2 (AP group), group 3 (AP + low-dose certolizumab group), group 4 (AP + high-dose certolizumab group), and group 5 (placebo group). Rats in all groups were sacrificed 24 hours after the last injection and amylase, tumor necrosis factor α, transforming growth factor β, interleukin 1β, malondialdehyde, superoxide dismutase, and glutathione peroxidase levels were studied in blood samples. Histopathological investigation of both the pancreas and target organs (lungs, liver, heart, kidneys) was performed by a pathologist blind to the groups. In silico analysis were also accomplished.

RESULTS

The biochemical results in the certolizumab treatment groups were identified to be significantly favorable compared to the AP group (P < 0.001). The difference between the high-dose group (group 4) and low-dose treatment group (group 3) was found to be significant in terms of biochemical parameters and histopathological scores (P < 0.001). In terms of the effect of certolizumab treatment on the target organs (especially on lung tissue), the differences between the low-dose treatment group (group 3) and high-dose treatment group (group 4) with the AP group (group 2) were significant.

CONCLUSIONS

Certolizumab has favorable protective effects on pancreas and target organs in AP. It may be a beneficial agent for AP treatment and may prevent target organ damage.

Efficacy of Agmatine Treatment in Experimental Acute Pancreatitis Rat Model

BACKGROUND/AIMS

Acute pancreatitis which is characterized by pancreatic inflammation can sometimes be difficult to treat because of limited therapeutic options. The purpose of the study was to assess the effects of agmatine in the acute pancreatitis experimental rat model.

MATERIALS AND METHODS

An acute pancreatitis model was created with the administration of cerulein in 40 female Sprague-Dawley rats. Agmatine was administered as a protective agent at 5 mg/kg (low dose) and 10 mg/kg (high dose). The rats were divided into 5 groups, each with 8 rats: group 1 (acute pancreatitis); group 2 (acute pancreatitis+low-dose agmatine 5 mg/kg); group 3 (acute pancreatitis+high-dose agmatine 10 mg/kg); group 4 (placebo, acute pancreatitis+saline); and group 5 (sham and saline infusion). All rats were sacrificed 24 hours after the last injection, and the levels of superoxide dismutase, interleukin-1 beta, and tumor necrosis factor-alpha were assessed in blood samples collected via cardiac puncture. Histopathological examination was performed by a pathologist, who was blind to the groups, according to the Schoenberg's pancreatitis scoring index.

RESULTS

The amylase (16.67 and 37.89 U/L), glutathione peroxidase (13.62 and 18.44 ng/mL), tumor necrosis factor-α (39.68 and 64 ng/mL), interleukin-1 (484.73 and 561.83 pg/mL), and transforming growth factor-β (110.52 and 126.34 ng/L) levels were significantly lower and superoxide dismutase (1.29 and 0.98 ng/L) and malondialdehyde (0.99 and 0.96 nmol/mL) levels were significantly higher in group 3 compared to group 1 (P < .05). Moreover glutathione peroxidase, tumor necrosis factor-α, and transforming growth factor-β levels were lower, and malondialdehyde levels were higher in the group 3 compared to group 2 (P < .05). Although the Schoenberg's pancreatitis scoring index was not significantly different between the high- and low-dose treatment groups, rats who received high-dose treatment had significantly lower scores compared to those with acute pancreatitis group.

CONCLUSION

This is the first study that evaluated the efficacy of agmatine in an experimental model of acute pancreatitis. Agmatine, an anti-inflammatory and antioxidant agent, had a protective effect in an experimental rat model of acute pancreatitis.

Anti-drug resistance, anti-inflammation, and anti-proliferation activities mediated by melatonin in doxorubicin-resistant hepatocellular carcinoma: in vitro investigations

Hepatocellular carcinoma (HCC) is the major life-threatening primary liver malignancy in both sexes all over the world. Unfortunately, the majority of patients are diagnosed at later stages because HCC does not elicit obvious symptoms during its early incidence. Consequently, most individuals escape the first-line HCC treatments and are treated with chemotherapy. Regrettably, the therapeutic outcomes for those patients are usually poor because of the development of multidrug resistance phenomena. Furthermore, most anti-HCC therapies cause severe undesired side effects that notably interfere with the life quality of such patients. Accordingly, there is an important need to search for an alternative therapeutic drug or adjuvant which is more efficient with safe or even minimal side effects for HCC treatment. Melatonin was recently reported to exert intrinsic antitumor activity in different cancers. However, the regulatory pathways underlying the antitumor activity of melatonin are poorly understood in resistant liver cells. Furthermore, a limited number of studies have addressed the therapeutic role of melatonin in HCC cells resistant to doxorubicin chemotherapy. In this study, we investigated the antitumor effects of melatonin in doxorubicin-resistant HepG2 cells and explored the regulatory pivotal targets underlying these effects. To achieve our aim, an MTT assay was used to calculate the 50% inhibitory concentration of melatonin and evaluate its antiproliferative effect on resistant cells. Additionally, qRT-PCR was used to quantify genes having a role in drug resistance phenotype (ABCB1, ABCC1, ABCC2, ABCC3, ABCC4, ABCC5, and ABCG2); apoptosis (caspases-3, and -7, Bcl2, Bax, and p53); anti-oxidation (NRF2); expression of melatonin receptors (MT1, MT2, and MT3); besides, programmed death receptor PD-1 gene. The active form of the caspase-3 enzyme was estimated by ELISA. A human inflammatory antibody membrane array was employed to quantify forty inflammatory factors expressed in treated cells. We observed that melatonin inhibited the proliferation of doxorubicin-resistant HepG2 cells in a dose-dependent manner after 24-h incubation time with a calculated IC₅₀ greater than 10 mM (13.4 mM), the expression levels of genes involved in drug resistance response (ABCB1, ABCC1, ABCC5, and ABCG2) were downregulated. Also, the expression of caspase-3, Caspase-7, NRF2, and p53 genes were expressed at higher levels as compared to control (DMSO-treated cells). An active form of caspase-3 was confirmed by ELISA. Moreover, the anti-inflammatory effect of melatonin was detected through the calculated fold change to control which was reduced for various mediators that have a role in the inflammation pathway. The current findings introduce melatonin as a promising anti-cancer treatment for human-resistant HCC which could be used in combination with current chemotherapeutic regimens to improve the outcome and reduce the developed multidrug resistance.

Differential expressions of miR-223, miR-424, miR-145, miR-200c, miR-139 in experimental rat chronic pancreatitis model and their relationship between oxidative stress, endoplasmic reticulum stress, and apoptosis

OBJECTIVES

This study aimed to research the roles of miR-139, miR-221, miR-200c, miR-145, miR-223, miR-424, and miR-377 in endoplasmic reticulum stress (ERS), oxidative stress (OS), fibrosis, and apoptosis processes in chronic pancreatitis (CP) rat model.

MATERIALS AND METHODS

Fourteen rats were randomized into 2 groups (Group 1, sham group (n=7) and Group 2, CP group (n=7)). TGF-beta and malondialdehyde concentrations were measured in rat blood samples. qRT-PCR was used to investigate the expression levels of 7 miRNAs in the pancreas tissues. The correlations of mRNA undergoing significant changes with inflammation (TNF-α, IL-6), ERS (Ire1-α, Perk), apoptosis (Caspase 3, Bcl-2), OS (Cat, Gpx1), and fibrosis (α-Sma) were investigated .

RESULTS

The biochemical results and histopathological scores in Group 1 were statistically significantly high compared with Group 2 (P<0.5). Expression levels of seven miRNAs (miR-200c, miR-145, miR-223, miR-424) were significantly higher, while miR-139 was significantly lower in CP. In our study, we found that miR-200c, miR-145, and miR-139 may contribute to CP progression and cellular processes based on the correlation between ERS, OS, apoptosis, and inflammation with miRNA expression levels.

CONCLUSION

miR-200c, miR-145, miR-139, miR-223, and miR-424 play roles in the CP model. They may be used as candidate biomarkers for the CP process.