Curcumin downregulates p38 MAPK-dependent X-ray repair cross-complement group 1 (XRCC1) expression to enhance cisplatin-induced cytotoxicity in human lung cancer cells

Exploring Synergistic Interactions between Natural Compounds and Conventional Chemotherapeutic Drugs in Preclinical Models of Lung Cancer

In the current work, the synergy between natural compounds and conventional chemotherapeutic drugs is comprehensively reviewed in light of current preclinical research findings. The prognosis for lung cancer patients is poor, with a 5-year survival rate of 18.1%. The use of natural compounds in combination with conventional chemotherapeutic drugs has gained significant attention as a potential novel approach in the treatment of lung cancer. The present work highlights the importance of finding more effective therapies to increase survival rates. Chemotherapy is a primary treatment option for lung cancer but it has limitations such as reduced effectiveness because cancer cells become resistant. Natural compounds isolated from medicinal plants have shown promising anticancer or chemopreventive properties and their synergistic effect has been observed when combined with conventional therapies. The combined use of an anti-cancer drug and a natural compound exhibits synergistic effects, enhancing overall therapeutic actions against cancer cells. In conclusion, this work provides an overview of the latest preclinical research on medicinal plants and plant-derived compounds as alternative or complementary treatment options for lung cancer chemotherapy and discusses the potential of natural compounds in treating lung cancer with minimal side effects.

Exploring homologous recombination repair and base excision repair pathway genes for possible diagnostic markers in hematologic malignancies

Hematologic malignancies (HMs) are a collection of malignant transformations, originating from the cells in the bone marrow and lymphoid organs. HMs comprise three main types; leukemia, lymphoma, and multiple myeloma. Globally, HMS accounts for approximately 10% of newly diagnosed cancer. DNA repair pathways defend the cells from recurrent DNA damage. Defective DNA repair mechanisms such as homologous recombination repair (HRR), nucleotide excision repair (NER), and base excision repair (BER) pathways may lead to genomic instability, which initiates HM progression and carcinogenesis. Expression deregulation of HRR, NER, and BER has been investigated in various malignancies. However, no studies have been reported to assess the differential expression of selected DNA repair genes combinedly in HMs. The present study was designed to assess the differential expression of HRR and BER pathway genes including RAD51, XRCC2, XRCC3, APEX1, FEN1, PARP1, and XRCC1 in blood cancer patients to highlight their significance as diagnostic/ prognostic marker in hematological malignancies. The study cohort comprised of 210 blood cancer patients along with an equal number of controls. For expression analysis, q-RT PCR was performed. DNA damage was measured in blood cancer patients and controls using the comet assay and LORD Q-assay. Data analysis showed significant downregulation of selected genes in blood cancer patients compared to healthy controls. To check the diagnostic value of selected genes, the Area under curve (AUC) was calculated and 0.879 AUC was observed for RAD51 (p < 0.0001) and 0.830 (p < 0.0001) for APEX1. Kaplan-Meier analysis showed that downregulation of RAD51 (p < 0.0001), XRCC3 (p < 0.02), and APEX1 (p < 0.0001) was found to be associated with a significant decrease in survival of blood cancer patients. Cox regression analysis showed that deregulation of RAD51 (p < 0.0001), XRCC2 (p < 0.02), XRCC3 (p < 0.003), and APEX1 (p < 0.00001) was found to be associated with the poor prognosis of blood cancer patients. Comet assay showed an increased number of comets in blood cancer patients compared to controls. These results are confirmed by performing the LORD q-assay and an increased frequency of lesions/Kb was observed in selected genes in cancer patients compared to controls. Our results showed significant downregulation of RAD51, XRCC2, XRCC3, APEX1, FEN1, PARP1, and XRCC1 genes with increased DNA damage in blood cancer patients. The findings of the current research suggested that deregulated expression of HRR and BER pathway genes can act as a diagnostic/prognostic marker in hematologic malignancies.

Curcumin and Its Analogs in Non-Small Cell Lung Cancer Treatment: Challenges and Expectations

Researchers have made crucial advances in understanding the pathogenesis and therapeutics of non-small cell lung cancer (NSCLC), improving our understanding of lung tumor biology and progression. Although the survival of NSCLC patients has improved due to chemoradiotherapy, targeted therapy, and immunotherapy, overall NSCLC recovery and survival rates remain low. Thus, there is an urgent need for the continued development of novel NSCLC drugs or combination therapies with less toxicity. Although the anticancer effectiveness of curcumin (Cur) and some Cur analogs has been reported in many studies, the results of clinical trials have been inconsistent. Therefore, in this review, we collected the latest related reports about the anti-NSCLC mechanisms of Cur, its analogs, and Cur in combination with other chemotherapeutic agents via the Pubmed database (accessed on 18 June 2022). Furthermore, we speculated on the interplay of Cur and various molecular targets relevant to NSCLC with discovery studio and collected clinical trials of Cur against NSCLC to clarify the role of Cur and its analogs in NSCLC treatment. Despite their challenges, Cur/Cur analogs may serve as promising therapeutic agents or adjuvants for lung carcinoma treatment.

Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

Nanoscale Formulations: Incorporating Curcumin into Combination Strategies for the Treatment of Lung Cancer

Lung cancer remains the most common cancer worldwide. Although significant advances in screening have been made and early diagnosis strategies and therapeutic regimens have been developed, the overall survival rate remains bleak. Curcumin is extracted from the rhizomes of turmeric and exhibits a wide range of biological activities. In lung cancer, evidence has shown that curcumin can markedly inhibit tumor growth, invasion and metastasis, overcome resistance to therapy, and even eliminate cancer stem cells (CSCs). Herein, the underlying molecular mechanisms of curcumin were summarized by distinct biological processes. To solve the limiting factors that curtail the clinical applications of curcumin, nanoformulations encapsulating curcumin were surveyed in detail. Nanoparticles, including liposomes, micelles, carbon nanotubes (CNTs), solid lipid nanoparticles (SLNs), nanosuspensions, and nanoemulsions, were explored as proper carriers of curcumin. Moreover, it was firmly verified that curcumin has the ability to sensitize lung cancer cells to chemotherapeutic drugs, such as cisplatin and docetaxel, and to various targeted therapies. Regarding the advantages and drawbacks of curcumin, we concluded that combination therapy based on nanoparticles would be the optimal approach to broaden the application of curcumin in the clinic in the near future.

Baicalin attenuates XRCC1-mediated DNA repair to enhance the sensitivity of lung cancer cells to cisplatin

Baicalin plays important roles in different types of cancer. A previous report showed that baicalin attenuates cisplatin resistance in lung cancer. However, its mechanism remains unclear. In this study, we investigated the effect and mechanism of baicalin on DNA repair and sensitivity of lung cancer cells to cisplatin. A549 and A549/DPP cells were treated with baicalin and cisplatin. A549/DPP cells were transfected with XRCC1 and siXRCC1. Cell viability and DNA damage were detected by MTT and comet assay. Apoptosis rate and cell cycle were detected by flow cytometry assay. The expressions of Bax, Bcl-2, and Cyclin D1 were detected by western blot. XRCC1 expression was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot. Baicalin and cisplatin decreased cell viability in A549 and A549/DPP cells in dose-dependent manner. Baicalin enhanced the effect of cisplatin on promoting apoptosis, arresting cell on S stage and triggering DNA damage accompanied with the upregulation of Bcl-2-associated X protein (Bax) and downregulation of B-cell lymphoma 2 (Bcl-2) and Cyclin D1 in A549/DPP cells. Moreover, baicalin promoted the inhibitory effect of cisplatin on XRCC1 expression in A549 and A549/DPP cells. However, the synthetic effects of baicalin and cisplatin on A549/DPP cells were partially inhibited by XRCC1 overexpression and promoted by XRCC1 knockdown. This study demonstrates that baicalin interferes with XRCC1-mediated cellar DNA repair to sensitize lung cancer cells to cisplatin.

Gonadotropin-inhibiting hormone promotes apoptosis of bovine ovary granulosa cells

Gonadotropin-inhibiting hormone (GnIH) inhibits the synthesis and release of gonadotropin by binding to its receptor. GnIH is involved in animal reproductive regulation, especially ovary function. It can regulate the proliferation, apoptosis and hormone secretion of follicular cells. However, the role and molecular mechanism of GnIH in bovine granulosa cell (bGC) apoptosis is unclear. Here, the effects of GnIH on proliferation, apoptosis, and mitochondrial function of bGCs were detected. A 10^-6 mol/mL concentration of GnIH inhibited bGC proliferation, promoted GC apoptosis, and damaged mitochondrial function. Additionally, GnIH significantly decreased the phosphorylation level of p38 (P < 0.01). To explore the role of the p38 signaling pathway in the process of GnIH-induced apoptosis in bGCs, an activator of p38 (U46619) was used to pretreat bGCs. U46619 pretreatment significantly alleviated GnIH damage to bGCs, including proliferation, apoptosis, and mitochondrial function. In conclusion, these results demonstrated that GnIH inhibited proliferation and promoted apoptosis of bGCs via the p38 signaling pathway.

Natural Compounds That Target DNA Repair Pathways and Their Therapeutic Potential to Counteract Cancer Cells

Resistance to current cancer treatments is an important problem that arises through various mechanisms, but one that stands out involves an overexpression of several factors associated with DNA repair. To counteract this type of resistance, different drugs have been developed to affect one or more DNA repair pathways, therefore, to test different compounds of natural origin that have been shown to induce cell death in cancer cells is paramount. Since natural compounds target components of the DNA repair pathways, they have been shown to promote cancer cells to be resensitized to current treatments. For this and other reasons, natural compounds have aroused great curiosity and several research projects are being developed around the world to establish combined treatments between them and radio or chemotherapy. In this work, we summarize the effects of different natural compounds on the DNA repair mechanisms of cancer cells and emphasize their possible application to re-sensitize these cells.

Versatile role of curcumin and its derivatives in lung cancer therapy

Lung cancer is a main cause of death all over the world with a high incidence rate. Metastasis into neighboring and distant tissues as well as resistance of cancer cells to chemotherapy demand novel strategies in lung cancer therapy. Curcumin is a naturally occurring nutraceutical compound derived from Curcuma longa (turmeric) that has great pharmacological effects, such as anti-inflammatory, neuroprotective, and antidiabetic. The excellent antitumor activity of curcumin has led to its extensive application in the treatment of various cancers. In the present review, we describe the antitumor activity of curcumin against lung cancer. Curcumin affects different molecular pathways such as vascular endothelial growth factors, nuclear factor-κB (NF-κB), mammalian target of rapamycin, PI3/Akt, microRNAs, and long noncoding RNAs in treatment of lung cancer. Curcumin also can induce autophagy, apoptosis, and cell cycle arrest to reduce the viability and proliferation of lung cancer cells. Notably, curcumin supplementation sensitizes cancer cells to chemotherapy and enhances chemotherapy-mediated apoptosis. Curcumin can elevate the efficacy of radiotherapy in lung cancer therapy by targeting various signaling pathways, such as epidermal growth factor receptor and NF-κB. Curcumin-loaded nanocarriers enhance the bioavailability, cellular uptake, and antitumor activity of curcumin. The aforementioned effects are comprehensively discussed in the current review to further direct studies for applying curcumin in lung cancer therapy.

Therapeutic potentials of curcumin in the treatment of non-small-cell lung carcinoma

Non-small-cell lung carcinoma (NSCLC) is one of the most lethal malignancies that include more than 80% of lung cancer cases worldwide. During the past decades, plants and plant-derived products have attracted great interest in the treatment of various human diseases. Curcumin, the turmeric isolated natural phenolic compound, has shown a promising chemo-preventive and anticancer agent. Numerous studies have shown that curcumin delays the initiation and progression of NSCLC by affecting a wide range of molecular targets and cell signalling pathways including NF-kB, Akt, MAPKS, BCL-2, ROS and microRNAs (miRNAs). However, the poor oral bioavailability and low chemical stability of curcumin remain as major challenges in the utilisation of this compound as a therapeutic agent. Different analogs of curcumin and new delivery systems (e.g., micelles, nanoparticles and liposomes) provided promising solutions to overcome these obstacles and improve curcumin pharmacokinetic profile. The present review focuses on current reported studies about anti-NSCLC effects of curcumin. NSCLC involved miRNAs whose expression is regulated by curcumin has also been discussed. Furthermore, recent researches on the use of curcumin analogs and delivery systems to enhance the curcumin benefits in NSCLC are also described.

Anti-Cancer and Ototoxicity Characteristics of the Curcuminoids, CLEFMA and EF24, in Combination with Cisplatin

In this study, we investigated whether the curcuminoids, CLEFMA and EF24, improved cisplatin efficacy and reduced cisplatin ototoxicity. We used the lung cancer cell line, A549, to determine the effects of the curcuminoids and cisplatin on cell viability and several apoptotic signaling mechanisms. Cellular viability was measured using the MTT assay. A scratch assay was used to measure cell migration and fluorescent spectrophotometry to measure reactive oxygen species (ROS) production. Western blots and luminescence assays were used to measure the expression and activity of apoptosis-inducing factor (AIF), caspases-3/7, -8, -9, and -12, c-Jun N-terminal kinases (JNK), mitogen-activated protein kinase (MAPK), and proto-oncogene tyrosine-protein kinase (Src). A zebrafish model was used to evaluate auditory effects. Cisplatin, the curcuminoids, and their combinations had similar effects on cell viability (IC₅₀ values: 2-16 μM) and AIF, caspase-12, JNK, MAPK, and Src expression, while caspase-3/7, -8, and -9 activity was unchanged or decreased. Cisplatin increased ROS yield (1.2-fold), and curcuminoid and combination treatments reduced ROS (0.75-0.85-fold). Combination treatments reduced A549 migration (0.51-0.53-fold). Both curcuminoids reduced auditory threshold shifts induced by cisplatin. In summary, cisplatin and the curcuminoids might cause cell death through AIF and caspase-12. The curcuminoids may potentiate cisplatin's effect against A549 migration, but may counteract cisplatin's effect to increase ROS production. The curcuminoids might also prevent cisplatin ototoxicity.

Combinations of the antioxidants sulforaphane or curcumin and the conventional antineoplastics cisplatin or doxorubicin as prospects for anticancer chemotherapy

Drugs used in clinical oncology have narrow therapeutic indices with adverse toxicity often involving oxidative damage. Chemoresistance to these conventional antineoplastics is usually mediated by oxidative stress-upregulated pathways such as those of nuclear factor-kappa B (NF-κB) and hypoxia-inducible factor-1 alpha (HIF-1α). Accordingly, the use of antioxidants in combinational approaches has begun to be considered for fighting cancer because of both the protective role against adverse effects and the ability to sensitize chemoresistant cancer cells. Nuclear factor erythroid 2-related factor 2 (Nrf2) has been identified as a mediator of the cytoprotection but it is not regularly associated with tumor chemosensitization. However, some Nrf2 inducers could be exerting cytoprotective and chemosensitizing roles through a simple integrated mechanism in which the cellular level of reactive oxygen species is controlled, thus inhibiting the oxidative damage in non-target tissues and the tumor chemoresistance mediated by NF-κB or HIF-1α. As examples to show the general idea of this antioxidant combination chemotherapy, this review explores the preclinical information available for four combinations, each composed by a paradigmatic oncological drug (cisplatin or doxorubicin) and a recognized antioxidant (sulforaphane or curcumin). The issues for translating these outcomes to clinical trials are briefly discussed.

Effect of mitomycin C on X-ray repair cross complementing group 1 expression and consequent cytotoxicity regulation in human gastric cancer cells

Gastric cancer is the fourth most common cancer and ranks as the second leading cause of cancer-related deaths across the world. The combination therapy of surgery with chemotherapeutic drugs, that is, mitomycin C (MMC), is becoming a major strategy for patients with advanced gastric cancer. However, drug resistance is a major factor that limits the effectiveness of chemotherapy, which ultimately leads to the failure of cancer chemotherapy. X-ray repair cross complementing group 1 (XRCC1), a scaffold protein of the base excision repair process, has been implicated in the development of tumor chemoresistance. Thus, this study aimed to explore whether XRCC1 expression could be regulated, its role in gastric AGS cancer cells treated with MMC, and the underlying mechanism. The results of this study demonstrate that XRCC1 expression could be upregulated in AGS cells treated with MMC, and this upregulation could subsequently reduce the cytotoxicity of MMC in AGS cells. Furthermore, MMC-upregulated XRCC1 expression was regulated by MAPK signaling through activating the transcription factor Sp1. These results indicate the role of XRCC1 in the development of drug resistance to MMC in gastric AGS cells. Elucidating the mechanism concerning the MAPKs and transcription factor Sp1 may provide another notion for the development of a clinical chemotherapy strategy for gastric cancers in the future.

Phytochemicals: Current strategy to sensitize cancer cells to cisplatin

Cisplatin-based chemotherapeutic regimens are the most frequently used adjuvant treatments for many types of cancer. However, the development of chemoresistance to cisplatin results in treatment failure. Despite the significant developments in understanding the mechanisms of cisplatin resistance, effective strategies to enhance the chemosensitivity of cisplatin are lacking. Phytochemicals are naturally occurring plant-based compounds that can augment the anti-cancer activity of cisplatin, with minimal side effects. Notably, some novel phytochemicals, such as curcumin, not only increase the efficacy of cisplatin but also decrease toxicity induced by cisplatin. However, the exact mechanisms underlying this process remain unclear. In this review, we discussed the progress made in utilizing phytochemicals to enhance the anti-cancer efficacy of cisplatin. We also presented some ideal phytochemicals as novel agents for counteracting cisplatin-induced organ damage.

An integrated approach to elucidate signaling pathways of dioscin-induced apoptosis, energy metabolism and differentiation in acute myeloid leukemia

Although the therapeutics have improved the rates of remission and cure of acute myelogenous leukemia (AML) in recent decades, there is still an unmet medical need for AML therapies because disease relapses are a major obstacle in patients who become refractory to salvage therapy. The development of therapeutic agents promoting both cytotoxicity and cell differentiation may provide opportunities to improve the clinical outcome. Dioscin-induced apoptosis in leukemic cells was identified through death receptor-mediated extrinsic apoptosis pathway. The formation of Bak and tBid, and loss of mitochondrial membrane potential were induced by dioscin suggesting the activation of intrinsic apoptotsis pathway. A functional analysis of transcription factors using transcription factor-DNA interaction array and IPA analysis demonstrated that dioscin induced a profound increase of protein expression of CCAAT/enhancer-binding protein α (C/EBPα), a critical factor for myeloid differentiation. Two-dimensional gel electrophoresis assay confirmed the increase of C/EBPα expression. Dioscin-induced differentiation was substantiated by an increase of CD11b protein expression and the induction of differentiation toward myelomonocytic/granulocytic lineages using hematoxylin and eosin staining. Moreover, both glycolysis and gluconeogenesis pathways after two-dimensional gel electrophoresis assay and IPA network enrichment analysis were proposed to dioscin action. In conclusion, the data suggest that dioscin exerts its antileukemic effect through the upregulation of both death ligands and death receptors and a crosstalk activation of mitochondrial apoptosis pathway with the collaboration of tBid and Bak formation. In addition, proteomics approach reveals an altered metabolic signature of dioscin-treated cells and the induction of differentiation of promyelocytes to granulocytes and monocytes in which the C/EBPα plays a key role.

Effect of AICAR and 5-Fluorouracil on X-ray Repair, Cross-Complementing Group 1 Expression, and Consequent Cytotoxicity Regulation in Human HCT-116 Colorectal Cancer Cells

Colorectal cancer (CRC) is one of the leading causes of cancer mortality and 5-Fluorouracil (5-FU) is the most common chemotherapy agent of CRC. A high level of X-ray repair cross complementing group 1 (XRCC1) in cancer cells has been associated with the drug resistance occurrence. Moreover, the activation of adenosine monophosphate (AMP)-activated protein kinase (AMPK) has been indicated to regulate the cancer cell survival. Thus, this study was aimed to examine whether XRCC1 plays a role in the 5-FU/AMPK agonist (AICAR)-induced cytotoxic effect on CRC and the underlying mechanisms. Human HCT-116 colorectal cells were used in this study. It was shown that 5-FU increases the XRCC1 expression in HCT-116 cells and then affects the cell survival through CXCR4/Akt signaling. Moreover, 5-FU combined with AICAR further result in more survival inhibition in HCT-116 cells, accompanied with reduced CXCR4/Akt signaling activity and XRCC1 expression. These results elucidate the role and mechanism of XRCC1 in the drug resistance of HCT-116 cells to 5-FU. We also demonstrate the synergistic inhibitory effect of AMPK on 5-FU-inhibited HCT-116 cell survival under the 5-FU and AICAR co-treatment. Thus, our findings may provide a new notion for the future drug regimen incorporating 5-FU and AMPK agonists for the CRC treatment.