Combined regimens of cisplatin and metformin in cancer therapy: A systematic review and meta-analysis

Targeting Cancer Stem Cells and Hedgehog Pathway: Enhancing Cisplatin Efficacy in Ovarian Cancer With Metformin

Ovarian cancer (OC) remains a leading cause of gynaecological cancer deaths due to late diagnosis and the emergence of resistance to platinum-based chemotherapy, like cisplatin (Cis). Here, we investigated the potential of metformin (Met), a drug commonly used for type 2 diabetes, to overcome Cis resistance in OC. Our findings revealed a synergistic effect of Met with Cis in inhibiting cell viability, proliferation and colony/sphere formation capacity in both cisplatin-sensitive (A2780) and -resistant (A2780/CDDP) ovarian cancer cell lines. This synergistic action triggered apoptosis through DNA damage, S-phase cell cycle arrest and modulation of autophagy. Met also significantly decreased the expression of pluripotency transcription factors (Oct-4, Sox2 and Nanog), indicating its potential to target cancer stem cells (CSCs). Furthermore, the combination therapy downregulated multidrug resistance protein 1 (MDR1) and excision repair cross-complementation group 1 (ERCC1) expression, thereby sensitising resistant cells to Cis-induced cytotoxicity. Additionally, the combination treatment suppressed the Hedgehog (Hh) signalling pathway, which is an important factor in inhibiting CSCs. Our study highlights the potential of the Met signalling pathway to synergise with Cis, overcoming therapeutic resistance in OC by targeting diverse cellular processes, including CSCs, and warrants further investigation in preclinical models.

Knockdown of IGF2BP2 overcomes cisplatin-resistance in lung cancer through downregulating Spon2 gene

BACKGROUND

Cisplatin (DDP) resistance has long posed a challenge in the clinical treatment of lung cancer (LC). Insulin-like growth factor 2 binding protein 2 (IGF2BP2) has been identified as an oncogenic factor in LC, whereas its specific role in DDP resistance in LC remains unclear.

RESULTS

In this study, we investigated the role of IGF2BP2 on DDP resistance in DDP-resistant A549 cells (A549/DDP) in vitro and in a DDP-resistant lung tumor-bearing mouse model in vivo. Additionally, methylated RNA immunoprecipitation sequencing (MeRIP-seq) was conducted to identify the potential mRNAs regulated by IGF2BP2, an N6-methyladenosine (m6A) regulator, in the tumor tissues of mice. Compared to normal tissues, IGF2BP2 levels were increased in LC tissues and in relapsed/resistant LC tissues. Most importantly, IGF2BP2 levels were significantly higher in relapsed/resistant LC tissues than in LC tissues. Significantly, knockdown of IGF2BP2 or DDP treatment inhibited A549 cell viability, migration, and cell cycle progression. Consistently, DDP treatment suppressed the viability and migration and triggered cell cycle arrest in A549/DDP cells in vitro, as well as reduced tumor volume and weight of A549/DDP tumor-bearing mice; meanwhile, the combination of DDP and IGF2BP2 siRNA further significantly inhibited A549/DDP cell growth in vitro and in vivo compared to DDP treatment alone. Furthermore, MeRIP-seq data showed that IGF2BP2 downregulation remarkably elevated m6A levels of spondin 2 (Spon2) and reduced mRNA levels of Spon2 in tumor tissues from A549 tumor-bearing mice. Meanwhile, the combination of DDP and IGF2BP2 siRNA notably reduced Spon2 levels, as well as inhibited the viability and induced apoptosis in A549/DDP cells; however, these effects were reversed by Spon2 overexpression.

CONCLUSION

Collectively, downregulation of IGF2BP2 could overcome DDP resistance in LC through declining the Spon2 gene expression in an m6A-dependent manner. These results may provide a new strategy for overcoming DDP resistance in LC.

Metformin Inhibited GSDME to Suppress M2 Macrophage Pyroptosis and Maintain M2 Phenotype to Mitigate Cisplatin-Induced Intestinal Inflammation

BACKGROUND

The continuous clinical use of cisplatin is prevented by gastrointestinal toxicity.

METHODS

Cisplatin was used to treat THP-1-derived macrophages to see its differential effects on different subtypes of macrophages. Wild-type and Gsdme-/- mice models were used to examine the effect of cisplatin and metformin on intestinal inflammation in vivo. The effect of GSDME on macrophage polarization was further confirmed by GSDME knockdown.

RESULTS

We found that M2 macrophages, with more cell blebbing and GSDME cleavage, were more sensitive to cisplatin-induced pyroptosis than M1 macrophages. Cisplatin was capable of enhancing the M1 phenotype, which was reversed by GSDME knockdown. GSDME contributed to M1 polarization and GSDME knockdown promoted M2 phenotype via STAT6 activation. Reduced intestinal inflammation and increased M2 macrophage numbers was detected in cisplatin-treated GSDME-knockout mice. Furthermore, metformin alleviated cisplatin-induced intestinal inflammation by reducing M2 pyroptosis and enhancing M2 phenotype through GSDME inhibition.

CONCLUSION

This is the first study to reveal the non-pyroptotic role of GSDME in macrophage polarization, revealing that metformin could be used in combination with cisplatin to reduce intestinal toxicity.

Metformin combined with cisplatin reduces anticancer activity via ATM/CHK2-dependent upregulation of Rad51 pathway in ovarian cancer

Ovarian cancer (OC) is the deadliest malignancy of the female reproductive system. The standard first-line therapy for OC involves cytoreductive surgical debulking followed by chemotherapy based on platinum and paclitaxel. Despite these treatments, there remains a high rate of tumor recurrence and resistance to platinum. Recent studies have highlighted the potential anti-tumor properties of metformin (met), a traditional diabetes drug. In our study, we investigated the impact of met on the anticancer activities of cisplatin (cDDP) both in vitro and in vivo. Our findings revealed that combining met with cisplatin significantly reduced apoptosis in OC cells, decreased DNA damage, and induced resistance to cDDP. Furthermore, our mechanistic study indicated that the resistance induced by met is primarily driven by the inhibition of the ATM/CHK2 pathway and the upregulation of the Rad51 protein. Using an ATM inhibitor, KU55933, effectively reversed the cisplatin resistance phenotype. In conclusion, our results suggest that met can antagonize the effects of cDDP in specific types of OC cells, leading to a reduction in the chemotherapeutic efficacy of cDDP.

Nanocarrier-mediated cancer therapy with cisplatin: A meta-analysis with a promising new paradigm

Aims

Cisplatin is a frontline chemotherapeutic utilized to attenuate multiple cancers in the clinic. Given its side-effects, a new cisplatin formulation which could prevent cytotoxicity, metabolic deficiencies and metastasis is much needed. This study investigates whether nanocarriers can provide a better mode of drug delivery in preclinical cancer models seeking a potent anticancer therapeutic agent.

Materials and methods

The PubMed database was searched, and 242 research articles were screened from which 94 articles qualified for selection from those published by December 31, 2023 and the data was synthesized using the Review Manager software.

Key findings

Cisplatin encapsulated as a nanomedicine confirmed the versatility of nanocarriers in significantly diminishing cancer cell viability, half maximal inhibitory concentration, tumour volume, biodistribution of platinum in tumours and kidney; at p < 0.00001 and a 95% confidence interval.

Significance

An estimated 19.3 million global cancer incidence is reported with 50% mortality worldwide for which nanocarrier-mediated cisplatin therapy is most promising. Our findings offer new vistas for future cancer treatment when combined with chemo-immunotherapy that utilizes the recently advanced nanozymes.

Fisetin enhances cisplatin sensitivity in renal cell carcinoma via the CDK6/PI3K/Akt/mTOR signaling pathway

Cisplatin resistance is ubiquitous among patients with renal cell carcinoma (RCC). The present study assessed the role of fisetin in regulating cisplatin sensitivity and increasing the efficacy of chemotherapy for patients with RCC. Cell Counting Kit-8 and colony formation assays were used to assess the proliferation of RCC cells after fisetin and cisplatin treatment. The mRNA expression levels of cyclin-dependent kinase (CDK)6 were evaluated using reverse transcription-quantitative PCR. The expression levels of CDK6 and key proteins of the PI3K/Akt/mTOR signaling pathway were assessed using western blotting. The present study demonstrated that fisetin inhibited the proliferation and colony-forming ability of RCC cells, and induced apoptosis and cell cycle arrest in a dose-dependent manner. Additionally, fisetin enhanced the antineoplastic effects of cisplatin, as demonstrated by the increase in proliferation inhibition and apoptosis promotion after fisetin and cisplatin combination treatment. Furthermore, fisetin regulated the PI3K/Akt/mTOR signaling pathway through CDK6 inhibition, which enhanced cisplatin sensitivity. Overexpression of CDK6 neutralized the positive effects of fisetin on the improvement of cisplatin sensitivity in RCC cells. In conclusion, fisetin may enhance the sensitivity of RCC cells to cisplatin via the CDK6/PI3K/Akt/mTOR signaling pathway.

Exploring the Synergistic Effect of Sildenafil and Green Tea Polyphenols on Breast Cancer Stem Cell-like Cells and their Parental Cells: A Potential Novel Therapeutic Approach

BACKGROUND

Many cancer studies have intensely focused on the role of diet, among other factors involved in cancer establishment. The positive effect of green tea polyphenols (GTP) on controlling breast cancer cells has been reported in several studies. Cancer stem cell-like cells (CSC-LCs) possessing self-renewal, metastatic, and drug-resistant capacities are considered prominent therapeutic targets. In many tumors, inducible nitric oxide synthase (iNOS) expression levels are high; however, they have a dual effect on breast cancer pathogenesis.

OBJECTIVE

This study aimed to investigate the cytotoxicity of the iNOS agonist (Sildenafil) and antagonist (LNAME), both alone and in combination with GTP, on MDA-MB-231, CD44+/CD24- CSC-LCs, and their parental cells (MCF-7).

METHODS

The cell viability assay has been studied using the MTT assay. To analyze drug-drug combinations, CompuSyn and Combenefit software were used. The cytotoxicity mechanism was determined using flow cytometric analysis.

RESULTS

L-NAME and GTP showed a synergistic effect on MDA-MB-231 and CSC-LCs. Such an effect was not observed on MCF-7. Sildenafil and GTP, on the other hand, showed synergistic cytotoxicity in all the cells mentioned above. Flow cytometric tests resulted in more than 70% apoptosis in MDA-MB-231 and MCF-7. Also, sub-G1 arrest among MCF-7 cells and a considerable decrease in ROS production by MDA-MB-231 cells following treatment with Sildenafil and GTP were observed.

CONCLUSION

Sildenafil, in combination with flavonoids, may be considered a novel strategy for cancer treatment.

Resveratrol as an antitumor agent for glioblastoma multiforme: Targeting resistance and promoting apoptotic cell deaths

Glioblastoma multiforme (GBM) is one of the most aggressive brain and spinal cord tumors. Despite the significant development in application of antitumor drugs, no significant increases have been observed in the survival rates of patients with GBM, as GBM cells acquire resistance to conventional anticancer therapeutic agents. Multiple studies have revealed that PI3K/Akt, MAPK, Nanog, STAT 3, and Wnt signaling pathways are involved in GBM progression and invasion. Besides, biological processes such as anti-apoptosis, autophagy, angiogenesis, and stemness promote GBM malignancy. Resveratrol (RESV) is a non-flavonoid polyphenol with high antitumor activity, the potential of which, regulating signaling pathways involved in cancer malignancy, have been demonstrated by many studies. Herein, we present the potential of RESV in both single and combination therapy- targeting various signaling pathways- which induce apoptotic cell death, re-sensitize cancer cells to radiotherapy, and induce chemo-sensitizing effects to eventually inhibit GBM progression.

Disparities in Cisplatin-Induced Cytotoxicity-A Meta-Analysis of Selected Cancer Cell Lines

Cisplatin is a classic anticancer drug widely used as a reference drug to test new metal complex drug candidates. We found an unexpected diversity in cisplatin-related cytotoxicity values, expressed as IC50 (the half-maximal inhibitory concentration) in tumour cell lines, such as MCF-7, HepG2 and HeLa. We reviewed the data published from 2018 to 2022. A total of 41 articles based on 56 in vitro experiments met our eligibility criteria. Using a meta-analysis based on a random effect model, we evaluated the cytotoxicity of cisplatin (IC50) after 48- or 72-h cell exposure. We found large differences between studies using a particular cell line. According to the random effect model, the 95% confidence intervals for IC50 were extremely wide. The heterogeneity of cisplatin IC50, as measured by the I2 index for all cancer cell lines, was over 99.7% at culture times of 48 or 72 h. Therefore, the variability between studies is due to experimental heterogeneity rather than chance. Despite the higher IC50 values after 48 h than after 72 h, the heterogeneity between the two culture periods did not differ significantly. This indicates that the duration of cultivation is not the main cause of heterogeneity. Therefore, the available data is diverse and not useful as a reference. We discuss possible reasons for the IC50 heterogeneity and advise researchers to conduct preliminary testing before starting experiments and not to solely rely on the published data. We hope that this systematic meta-analysis will provide valuable information for researchers searching for new cancer drugs using cisplatin as a reference drug.

Drug Repurposing in Oncology: A Systematic Review of Randomized Controlled Clinical Trials

Quality pharmacological treatment can improve survival in many types of cancer. Drug repurposing offers advantages in comparison with traditional drug development procedures, reducing time and risk. This systematic review identified the most recent randomized controlled clinical trials that focus on drug repurposing in oncology. We found that only a few clinical trials were placebo-controlled or standard-of-care-alone-controlled. Metformin has been studied for potential use in various types of cancer, including prostate, lung, and pancreatic cancer. Other studies assessed the possible use of the antiparasitic agent mebendazole in colorectal cancer and of propranolol in multiple myeloma or, when combined with etodolac, in breast cancer. We were able to identify trials that study the potential use of known antineoplastics in other non-oncological conditions, such as imatinib for severe coronavirus disease in 2019 or a study protocol aiming to assess the possible repurposing of leuprolide for Alzheimer's disease. Major limitations of these clinical trials were the small sample size, the high clinical heterogeneity of the participants regarding the stage of the neoplastic disease, and the lack of accounting for multimorbidity and other baseline clinical characteristics. Drug repurposing possibilities in oncology must be carefully examined with well-designed trials, considering factors that could influence prognosis.

Immunoregulation by resveratrol; implications for normal tissue protection and tumour suppression

Immune reactions are involved in both tumour and normal tissue in response to therapy. Elevated secretion of certain chemokines, exosomes and cytokines triggers inflammation, pain, fibrosis and ulceration among other normal tissue side effects. On the other hand, secretion of tumour-promoting molecules suppresses activity of anticancer immune cells and facilitates the proliferation of malignant cells. Novel anticancer drugs such as immune checkpoint inhibitors (ICIs) boost anticancer immunity via inducing the proliferation of anticancer cells such as natural killer (NK) cells and CD8+ T lymphocytes. Certain chemotherapy drugs and radiotherapy may induce anticancer immunity in the tumour, however, both have severe side effects for normal tissues through stimulation of several immune responses. Thus, administration of natural products with low side effects may be a promising approach to modulate the immune system in both tumour and normal organs. Resveratrol is a well-known phenol with diverse effects on normal tissues and tumours. To date, a large number of experiments have confirmed the potential of resveratrol as an anticancer adjuvant. This review focuses on ensuing stimulation or suppression of immune responses in both tumour and normal tissue after radiotherapy or anticancer drugs. Later on, the immunoregulatory effects of resveratrol in both tumour and normal tissue following exposure to anticancer agents will be discussed.

Mechanisms of cancer cell death induction by paclitaxel: an updated review

Chemoresistance of cancer cells is a major problem in treating cancer. Knowledge of how cancer cells may die or resist cancer drugs is critical to providing certain strategies to overcome tumour resistance to treatment. Paclitaxel is known as a chemotherapy drug that can suppress the proliferation of cancer cells by inducing cell cycle arrest and induction of mitotic catastrophe. However, today, it is well known that paclitaxel can induce multiple kinds of cell death in cancers. Besides the induction of mitotic catastrophe that occurs during mitosis, paclitaxel has been shown to induce the expression of several pro-apoptosis mediators. It also can modulate the activity of anti-apoptosis mediators. However, certain cell-killing mechanisms such as senescence and autophagy can increase resistance to paclitaxel. This review focuses on the mechanisms of cell death, including apoptosis, mitotic catastrophe, senescence, autophagic cell death, pyroptosis, etc., following paclitaxel treatment. In addition, mechanisms of resistance to cell death due to exposure to paclitaxel and the use of combinations to overcome drug resistance will be discussed.