Anti-Cancer Agents in Medicinal Chemistry (Formerly Current Medicinal Chemistry - Anti-Cancer Agents) - Volume 22, Issue 7, 2022

Application of immune checkpoint inhibitors (ICIs) is a major breakthrough in the field of cancer therapy, which has displayed tremendous potential in various types of malignancies. However, their response rates range widely in different cancer types and a significant number of patients experience immune-related adverse effects (irAEs) induced by these drugs, limiting the proportion of patients who can truly benefit from ICIs. Gut microbiota has gained increasing attention due to its emerging role in regulating the immune system. In recent years, numerous studies have shown that gut microbiota can modulate antitumor response, as well as decrease the risk of colitis due to ICIs in patients receiving immunotherapy. The present review analyzed recent progress of relevant basic and clinical studies in this area and explored new perspectives to enhance the efficacy of ICIs and alleviate associated irAEs via manipulation of the gut microbiota.

Tissues are progressively molded by bidirectional correspondence between denizen cells and extracellular matrix (ECM) via cell-matrix connections along with ECM remodeling. The composition and association of ECM are spatiotemporally directed to control cell conduct and differentiation; however, dysregulation of ECM dynamics prompts the development of diseases, for example, cancer. Emerging information demonstrates that hypoxia may have decisive roles in metastasis. In addition, the sprawling nature of neoplastic cells and chaotic angiogenesis are increasingly influencing microcirculation as well as altering the concentration of oxygen. In various regions of the tumor microenvironment, hypoxia, an essential player in the multistep phase of cancer metastasis, is necessary. Hypoxia can be turned into an advantage for selective cancer therapy because it is much more severe in tumors than in normal tissues. Cellular matrix gives signaling cues that control cell behavior and organize cells' elements in tissue development and homeostasis. The interplay between intrinsic factors of cancer cells themselves, including their genotype and signaling networks, and extrinsic factors of tumor stroma, for example, ECM and ECM remodeling, together decide the destiny and behavior of tumor cells. Tumor matrix encourages the development, endurance, and invasion of neoplastic and immune cell activities to drive metastasis and debilitate treatment. Incipient evidence recommends essential parts of tumor ECM segments and their remodeling in controlling each progression of the cancer-immunity cycle. Scientists have discovered that tumor matrix dynamics as well as matrix remodeling in perspective to anti-tumor immune reactions are especially important for matrix-based biomarkers recognition and followed by immunotherapy and targeting specific drugs.

It is well known that cancer is the second leading cause of death worldwide. Due to this fact, new results for the treatment of cancer are constantly being introduced and verified. Imidazolidine derivatives regulate cell cycle progression and DNA stability. Structurally, a heterocyclic nucleus favors a direct DNA interaction and therefore, control of the DNA replication process. This review aims not only to discuss the role of imidazolidines in cancer therapy but also explore the functionality of such agents in the future aspects of cancer prognosis and treatment. Convincing data from 1996 to 2021 has presented imidazolidine derivatives as a relevant therapeutic tool to modulate cancer progression and malignancy. Here we highlight these aspects in a variety of cell lines, cancer types, involving in vitro and in vivo techniques.

Background: In advanced non-small-cell lung cancer, without activating mutations and with PD-L1≥50%, Pembrolizumab monotherapy is the therapeutic standard in Europe. Objective: To evaluate retrospectively the safety and efficacy of this drug and to investigate potential prognostic factors in daily clinical practice. Methods: From September 2017 to September 2019, 205 consecutive patients from 14 Italian Medical Oncology Units were enrolled in the study. Gender, Age (> or <70 years), ECOG-PS (0-1 or 2), histology (squamous or nonsquamous), presence of brain, bone and liver metastases at baseline, PD-L1 score (>90% or <90%), smoking status (never or former or current) were applied to the stratified log-rank. Cox’s proportional hazards model was used for multivariate analysis. Results: At a median follow-up of 15.2 months, median progression-free and overall survival (mPFS and mOS) were 9.2 months (95% C.I., 4.8-13.5) and 15.9 months (95% C.I., not yet evaluable), respectively. Patients with Eastern Cooperative Oncology Group performance status (ECOG-PS) 2 had mPFS of 2.8 months (95% C.I., 2.1-3.4) and mOS of 3.9 months (95% C.I., 2.5-5.3). Patients with liver metastases at diagnosis had an mPFS of 3.2 months (95% C.I., 0.6-5.8) and an mOS of 6.0 months (95% C.I., 3.7-8.4). At multivariate analysis for OS gender, ECOG-PS 2, and presence of liver metastases were independent prognostic factors. Conclusion: Patients with ECOG-PS 2 derived little benefit from the use of first-line pembrolizumab. In patients with liver metastases, the association of pembrolizumab with platinum-based chemotherapy could be a better option than pembrolizumab alone.

Background: Photodynamic therapy has been increasingly used to cope with the alarming problem of cancer. Porphyrins and their derivatives are widely used as Potent Photosensitizers (PS) for PDT. However, the hydrophobicity of porphyrins poses a challenge for their use in clinics, while most of the carbon dots (CDs) are known for good biocompatibility, solubility, and pH sensitivity. Objective: This study aimed to improve the properties/biocompatibility of the pyropheophorbide-α for PDT. Methods: The PPa-CD conjugate was synthesized through covalent interaction using amide condensation. The structure of synthesized conjugate was confirmed by TEM, 1HNMR, and FTIR. The absorption and emission spectra were studied. In vitro, cytotoxicity of the conjugate was examined in human esophageal cancer cell line (Eca-109). Results: The results showed that the fluorescence of the drug was increased compared to its precursor. CDbased conjugate could generate ROS as well as enhanced biocompatibility by decreasing cytotoxicity. The conjugated drug also showed pH sensitivity in different solutions. Conclusion: The dark toxicity, as well as hemocompatibility, was improved.

Background: Colony-stimulating factor-1 (CSF1) is a cytokine that is closely related to normal organ growth and development as well as tumor progression. Objective: We aimed to summarize and clarify the reasons for the abnormal expression of CSF1 in tumors and explore the role of CSF1 in tumor progression. Furthermore, drug response analysis could provide a reference for clinical medication. Methods: The expression of CSF1 was analyzed by TCGA and CCLE. Besides, cBioPortal and MethSurv databases were used to conduct mutation and DNA methylation analyses. Further, correlations between CSF1 expression and tumor stage, survival, immune infiltration, drug sensitivity and enrichment analyses were validated via UALCAN, Kaplan-Meier plotter, TIMER, CTRP and Coexperia databases. Results: CSF1 is expressed in a variety of tissues; meaningfully, it can be detected in the blood. Compared with normal tissues, CSF1 expression was significantly decreased in most tumors. The missense mutation and DNA methylation of CSF1 might cause the downregulated expression. Moreover, decreased CSF1 expression was related to higher tumor stage and worse survival. Further, the promoter DNA methylation level of CSF1 was prognostically significant in most tumors. Besides, CSF1 was closely related to immune infiltration, especially macrophages. Importantly, CSF1 expression was associated with a good response to VEGFRs inhibitors, which may be due to the possible involvement of CSF1 in tumor angiogenesis and metastasis processes. Conclusion: The abnormal expression of CSF1 could serve as a promising biomarker of tumor progression and prognosis in pan-cancer. Significantly, angiogenesis and metastasis inhibitors may show a good response to CSF1-related tumors.

Background: Demethylincisterol A3 (DTA3) has been identified as an SHP2 inhibitor and suppresses the growth of many cancer cells. 5-Fluorouracil (5-FU) is widely used for the clinical treatment of various cancers. However, the combination effects of 5-FU and DTA3 on cervical cancer cells remain unknown. Objective: This study evaluates the mechanism of the combination effects of 5-FU and DTA3 in cervical cancer cells. Methods: The synergistic cytotoxic effects of 5-FU and DTA3 in cervical cancer cells were calculated. Apoptosis was analysed by flow cytometry. Western blot analyses were used to examine the related signalling pathways. Results: DTA3 and 5-FU synergized to induce apoptosis and repress proliferation of cervical cancer cells by downregulating the activation of PI3K/AKT and NF-ΚB signalling pathways. We provided evidence that the upregulation of SHP2 expression by transfection significantly inhibited the cytotoxicity of 5-FU and DTA3. SHP2 knockdown enhanced the anti-proliferation activity of 5-FU, indicating targeting SHP2 sensitized cervical cancer cells to 5-FU. Conclusion: Our study demonstrates that SHP2 inhibitor DTA3 and 5-FU have a synergistic cytotoxic effect on cervical cancer cells. The synergistic combination of SHP2 inhibitor and 5-FU may present a promising strategy for the treatment of cervical cancer.

Background: The anticancer activity of silibinin (SB) has been demonstrated in various cancer cell types. However, its low solubility and poor bioavailability limit its clinical potential in biomedical applications. Microbubbles in combination with ultrasound are promising vehicles for local drug delivery. Objective: The present study determined the antitumour effects and molecular mechanism of silibinin-loaded microbubbles (SBMBs) in combination with ultrasound on ovarian cancer in vitro. Methods: SBMBs were prepared using mechanical vibration. The viability of A2780 cells was determined using the MTT assay. Flow cytometry was performed to detect cell apoptosis and the cell cycle. The expression of Receptor Tyrosine Kinase (RTK)-associated downstream proteins was detected using multiplex assays and Western blots. Results: The present study designed and synthesized SBMBs. SBMBs in combination with ultrasound decreased A2780 cell viability in a dose- and time-dependent manner. The half maximal inhibitory concentration (IC50) showed that the cytotoxicity of the SBMBs was approximately 1.5 times greater than that of the SB in A2780 cells. SBMBs in combination with ultrasound resulted in significantly higher apoptosis efficiency compared to the SB group, and the SBMB population of cells was arrested in the G1/G0 phase. Further experiments demonstrated that SBMBs decreased the expression of signal transducer and activator of transcription 3 (STAT3), Ak strain transforming (AKT), and extracellular signal-regulated kinase (Erk) and had a greater effect than SB in A2780 cells. Inhibitors of AKT, Erk and STAT3 promoted the cytotoxicity of SBMBs. Conclusion: SBMBs in combination with ultrasound may enhance the cytotoxicity efficiency of SB via the promotion of apoptosis and cell cycle arrest in ovarian cancer cells and the inactivation of the STAT3, AKT and Erk signalling pathways.

Background: Prostate cancer (PCa) is the fourth most common tumor in males. Objective: This study aimed to investigate effects of atorvastatin (AS) on PCa cells proliferation and clarify the associated mechanisms. Methods: PCa cell lines were cultured and treated with irradiation (IR) (4 Gy), AS (6 μg/ml), transfected with Bcl-2 siRNA, and then divided into different groups. Xenograft tumor mouse model was established. Bcl-2 and MSH2 gene transcription and protein expression were evaluated using RT-PCR assay and western blot assay. Plate clone formation assay was employed to examine colony formation. MTT assay was used to detect cell viabilities. Flow cytometry analysis was utilized to verify apoptosis. Co-immunoprecipitation and immuno-fluorescence assay were used to identify interaction between Bcl-2 and MSH2. Results: IR significantly reduced colony formation, enhanced Bcl-2 and reduced MSH2 gene transcription in PCa cells compared to un-treated cells (p<0.05). AS significantly strengthened radio-therapeutic effects of IR on colony formation, decreased cell apoptosis and increased Bcl-2 gene transcription/protein expression in PCa cells compared to single IR treatment cells (p<0.05). AS combining IR down-regulated MSH2 gene transcription/protein expression in PCa cells compared to single IR treatment cells (p<0.05). Bcl-2 interacted with MSH2 both in PCa cells and tumor tissues administrating with AS. AS enhanced reductive effects of IR on tumor size of Xenograft tumor mice. Conclusion: Atorvastatin administration enhanced inhibitory effects of IR either on PCa cells or tumor size of Xenograft tumor mice. The inhibitory effects of atorvastatin were mediated by reducing MSH2 expression and triggering interaction between Bcl-2 and MSH2, both in vitro and in vivo levels.

Background: Although transplantation, surgical resection, and tumor ablation are treatment options available following early diagnosis of HCC, poor prognosis and high recurrence rates restrict the efficacy of these approaches. Hence, small molecules with high selectivity and bioactivity are urgently required. Objective: This study presents the synthesis of a series of new triazolothiadiazole derivatives (1a-3j) with NSAID moieties and their cytotoxic bioactivities. Methods: The new synthetic derivatives (1-3; 1a-3j) and NSAIDs ibuprofen, naproxen, and flurbiprofen that commonly used in clinics were screened against human liver (Huh7), breast (MCF7), and colon (HCT116) carcinoma cell lines under in vitro conditions via NCI-sulforhodamine B assay. Results: The 4-methoxyphenyl substituted condensed derivatives 1h, 2h, and 3h were the most active compounds. Based on its high potency, compound 3h was selected for the further biological evaluation of hepatocellular carcinoma cell lines, and the mechanisms underlying cell death induced by 3h were determined. The results revealed that compound 3h induced apoptosis and cell cycle arrest in the sub G1 phase in human liver cancer cells. Conclusion: These new small molecules may be used for the development of new lead compounds.

Background: It is estimated that more than 1 million people are diagnosed with liver malignancy each year and one of the treatments is radioembolization with Y-90 and Ho-166. Objective: The aim of this study is to calculate the absorbed doses caused by Y-90 and Ho-166 in tumor and liver parenchyma using a phantom via Monte Carlo method. Methods: A liver model phantom including a tumor imitation of sphere (r =1.5cm) was defined in GATE. The total activity of 40 mCi Y-90 and Ho-166 was prescribed into tumor imitation as source and 2x2x2 mm3 voxel-sized Dose- Actors were identified at 30 locations. The simulation, performed to calculate the absorbed doses left by particles during 1 second for Y-90 and Ho-166, was run for a total of 10 days and 11 days, respectively. Total doses were calculated by taking the doses occurring in 1 second as a reference. Results: The maximum absorbed doses were found to be 2.334E+03±1.576E+01 Gy for Y-90 and 7.006E+02±6.013E- 01 Gy for Ho-166 at the center of tumor imitation. The minimum absorbed doses were found to be 2.133E-03±1.883E- 01 Gy for Y-90 and 1.152E-02±1.036E-03 Gy for Ho-166 at the farthest location from source. The mean absorbed doses in tumor imitation were found to be 1.50E+03±1.36E+00 Gy and 4.58E+02±4.75E-01 Gy for Y-90 and Ho-166, respectively. And, the mean absorbed doses in normal parenchymal tissue were found to be2.07E+01±9.58E-02 Gy and 3.79E+00±2.63E-02 Gy for Y-90 and Ho-166, respectively. Conclusion: Based on the results, Ho-166 is a good alternative to Y-90 according to dosimetric evaluation.

Background: Wnt signaling cascades play important roles in cell fate decisions and their deregulation has been documented in many diseases, including malignant tumors and leukemia. One mechanism of aberrant Wnt signaling is the silencing of Wnt inhibitors through epigenetic mechanisms. The sFRPs are one of the most studied Wnt inhibitors; and the sFRP1 loss is known in many hematological malignancies. Therefore, we aimed to compare the expression of Wnt related genes in the presence and absence of sFRP1 in a chronic myeloid leukemia (CML) cell line. Objective: It is important to understand how sFRP1 and sFRP1 perform their effects on CML to design new agents and strategies for resistant and advanced forms of CML. Materials and Methods: We used K562 cells, which normally do not express sFRP1 and its sFRP1 expressing subclone K562s. Total RNA was isolated from K562 and K562s cell lines and converted to cDNA. PCR Array experiments were performed using Human Wnt Signaling Pathway Plus RT2 Profiler™ kit. Wnt signaling pathway activation was studied by western blot for downstream signaling targets. Results: The WNT3, LRP6, PRICKLE1 and BTRC expressions were significantly decreased in the presence of sFRP1; while WNT5B increased. The sFRP1 expression inhibited stabilization of total β-catenin protein and downstream effector phosphorylation of noncanonical Wnt/PCP signaling; whereas Ca2+/PKC signaling remained active. Conclusion: The results suggest that sFRP1 could be a promising therapeutic anticancer agent. Defining these pathway interactions is crucial for designing new agents resistant and advanced forms of CML.

Background: Survival and progression of cancer cells are highly dependent on aerobic glycolysis. Strobilanthes crispus has been shown to have promising anticancer effects on breast cancer cells. The involvement of the glycolysis pathway in producing these effects is unconfirmed, thus further investigation is required to elucidate this phenomenon. Objective: This study aims to determine the effect of S. crispus active fraction (F3) and its bioactive components on glycolysis in triple-negative breast cancer cells (MDA-MB-231). Methods: This study utilizes F3, lutein, β-sitosterol, and stigmasterol to be administered in MDA-MB-231 cells for measurement of antiglycolytic activities through cell poliferation, glucose uptake, and lactate concentration assays. Cell proliferation was assessed by MTT assay of MDA-MB-231 cells after treatment with F3 and its bioactive components lutein, β-sitosterol, and stigmasterol. The IC50 value in each compound was determined by MTT assay to be used in subsequent assays. The determination of glucose uptake activity and lactate concentration were quantified using fluorescence spectrophotometry. Results: Antiproliferative activities were observed for F3 and its bioactive components, with IC50 values of 100 μg/mL (F3), 20 μM (lutein), 25 μM (β-sitosterol), and 90 μM (stigmasterol) in MDA-MB-231 cells at 48 h. The percentage of glucose uptake and lactate concentration in MDA-MB-231 cells treated with F3, lutein, or β sitosterol were significantly lower than those observed in the untreated cells in a time-dependent manner. However, treatment with stigmasterol decreased the concentration of lactate without affecting the glucose uptake in MDA-MB-231 cells. Conclusion: The antiglycolytic activities of F3 on MDA-MB-231 cells are attributed to its bioactive components.

Background: Many natural and synthetic flavonoids have been studied and documented by inhibiting aromatase enzymes for their anti-cancer activity against breast carcinoma. The aromatase enzyme is a possible target for the estrogen's positive breast cancer receptor. Objective: Hence, a series of flavonoids have been synthesized and assessed for their in vitro cytotoxicity and aromatase inhibitory activity. Methods: 39 Flavonoids were synthesized and characterized by spectroscopic techniques, and their computational study was performed using the maestro version of the Schrodinger. In silico ADME properties were checked by QikProp software. A total of 18 compounds were evaluated based on the docking score using cytotoxicity assay in human breast cancer cell line MCF-7. Results: Of the 18 compounds tested, 07 compounds, namely 2b, 8b, 14b, 15b, 19b, 24b, and 30b flavonoids were found to be more active with their IC50 values of 20.73 μM, 1.636 μM, 16.08 μM, 22.02 μM, 15.75 μM, 0.345 μM and 16.08 μM, respectively, compared with the reference drug letrozole. The in vitro aromatase inhibitory activity of six compounds 2b, 8b, 14b, 19b, 24b, and 30b was conducted using a fluorogenic assay kit. The values of IC50 for compounds 2b and 24b were found to be 0.31 μM and 0.36 μM, respectively. Conclusion: Therefore, it was concluded that compounds 2b and 24b had a potent inhibitory effect of aromatase compared with letrozole with an IC50 value of 0.86 μM. At the same time, the other compounds 8b, 14b, 30b, and 19b were considered to have similar aromatase inhibitory activity. Hence, their essential aromatase inhibitory activities make them good lead candidates for developing potent inhibitors of aromatase.

Background: Triple-negative breast cancer (TNBC) accounts for 15% of all breast cancer (BC) cases and is a severe type of BC. Since medicinal herbs containing biocompatible substances that are accepted by patient more than chemical therapeutics, they can be considered a safe option for treating BC. Objective: This study evaluated the effect of Sambucus Ebulus (S. ebulus) extract on a model of TNBC. Methods: S. ebulus extract was prepared using petroleum ether, ethyl acetate, and methanol. The petroleum ether extract was fractionated and analyzed using vacuum liquid chromatography and GC-MS, respectively. MDAMB- 231 and MCF-10A were used as TNBC and normal breast cells, respectively. Flowcytometry and MTT assays were performed to evaluate cell cycle, apoptosis, and viability of the cells. Gene expression analysis was performed using RT-qPCR. Nude mouse allograft tumor models were used, and pathological sections were evaluated. Results: The findings indicated that S. ebulus extract remarkably decreased cell proliferation and viability. The extract had no toxicity to the normal breast cells but efficiently killed the cancer cells. Cell cycle- and apoptosisrelated gene expression showed that fraction 4 of S. ebulus extract significantly increased the expression of Bax, Bak, P53, and c-MYC. Conclusion: This study showed satisfactory results of the effect of S. ebulus extract on clearing BC cells both in vitro and in vivo. Thus, S. ebulus extract may be a safe herbal compound for eliminating BC cells without toxicity to host cells.

Background: Despite the advancement in the fields of medical science and molecular biology, cancer is still the leading cause of death worldwide. Chemotherapy is a choice for treatment; however, the acquisition of chemoresistance is a major impediment for cancer management. Many mechanisms have been postulated regarding the acquisition of chemo-resistance in breast cancer and the impact on cellular signalling and the induction of apoptosis in tumour cells. The mechanism of the apoptotic mutation ofp53 and bcl-2 proteins is commonly associated with increased resistance to apoptosis and, therein, to chemotherapy. Objectives: The current study was aimed to investigate A172 and MDA-MB-231 cancer cells’sensitivity against chemotherapeutic drugs, including cisplatin, doxorubicin, and paclitaxel with different doses. Moreover, it estimates resistance of cancer cells by evaluating Nitric Oxide Synthase (NOS) expression and evaluate its correlation with the expression profile proteins of the apoptosis regulating Bcl-2 family. Methods: Dose-dependent sensitivity to cisplatin, doxorubicin or paclitaxel was evaluated on spheroid cultured A172 and MDA-MB-231 cells lines, was measured by time-lapse microscopy over a 72h period. Expressions of two Nitric Oxide (NO) synthases isoforms (iNOS, eNOS), anti-apoptotic (Bcl-2, phospho-Bcl-2, Mcl-1, and Bcl-xL) and proapoptotic (BID, Bim, Bok, Bad, Puma, and Bax) were evaluated by Western blot. The effect of NO modulation on antiand pro-apoptotic molecule expression was also studied using Western blot. Results: A172 cells show more resistance to chemotherapy drugs than MDA-MB-231 cancer cells, therefore, they need higher doses for apoptosis. Resistance of gliomas might be returned to higher significant expression of endothelial eNOS expression. It was clear that there is not a significant effect of NO modulation on the expression of pro- andantiapoptotic proteins on both cell lines. Conclusion: The present work provides a putative mechanism for the acquisition of drug resistance in breast cancer and glioma, which might be significant for clinical outcomes.

Background: Urokinase-type plasminogen activator (uPA) system is a crucial pathway for tumor invasion and metastasis. Recently, multiple anticancer effects of quercetin have been described, including inhibitory activity against uPA. However, the clinical use of this flavonoid has been limited due to its low oral bioavailability. Objective: The objectives of the study were to assess the antimetastatic potential of quercetin analogues by analyzing their binding affinity for uPA, and to select the compounds with improved pharmacological profiles. Methods: Binding affinities of structural analogues of quercetin to uPA receptor were determined by molecular docking analysis using Molegro Virtual Docker software, and molecular descriptors relevant for estimating pharmacological profile were calculated from ligand structures using computational models. Results: Among 44 quercetin analogues, only one quercetin analogue (3,6,2’,4’,5’-pentahydroxyflavone) was found to possess higher aqueous solubility and membrane permeability, and stronger affinity for uPA than quercetin, which makes it a potential lead compound for anticancer drug development. Like quercetin, this compound has five hydroxyl groups, but arranged differently, which contributes to the higher aqueous solubility and higher amphiphilic moment in comparison to quercetin. Since membrane permeability is not recognized as the limiting factor for quercetin absorption, analogues with higher aqueous solubility and retained or stronger uPA inhibitory activity should also be further experimentally validated for potential therapeutic use. Conclusion: Identified quercetin analogues with better physicochemical and pharmacological properties have a high potential to succeed in later stages of research in biological systems as potential anticancer agents with antimetastatic activity.