Camptothecin Derivatives Research Articles

Advances in Anticancer Drug Discovery: Exploring the Untapped Potential of Natural Products for Targeted Therapies

Natural products have long been a significant source of structurally diverse and biologically active compounds, making them important for anticancer drug development. Taxol, a natural product isolated from the bark of the Pacific yew tree, is used to treat some cancers; Vincristine, a related compound that was eked out of the Madagascar periwinkle plant, treats leukemia and lymphoma. This review provides recent advances and future perspectives on developing natural-product-derived anticancer agents. We introduce celebrated examples of successfully developed natural-product-derived anticancer drugs, such as paclitaxel, doxorubicin, and camptothecin derivatives. We also discuss the hurdles of natural product-derived drug discovery, including limited availability, poor pharmacokinetics, and a lack of specificity to their intended targets. We will talk about some examples of these types of modification, including new developments in drug delivery systems, nanotechnology, and targeted drug delivery. These show how they could make natural product-derived anti-tumor drugs more effective and less harmful. It is emphasized that researchers from different fields, such as pharmacologists, catalyst chemists, drug delivery experts, rational drug designers, and nanotechnologists, will need to work together and research across disciplines for the project to succeed. This is so that problems and bottlenecks can be solved, and natural products can be used to make new anticancer drugs. Given the continuous and increasing global demand for novel anticancer drugs in the foreseeable future, natural products will remain a critically important source for discovering novel, safe, and effective anticancer drugs.

FL118 Enhances Therapeutic Efficacy in Colorectal Cancer by Inhibiting the Homologous Recombination Repair Pathway through Survivin-RAD51 Downregulation.

Background/Objectives: Irinotecan, a camptothecin (CPT) derivative, is commonly used as a first-line therapy for colorectal cancer (CRC), but resistance remains a significant challenge. This study aims to explore the therapeutic potential of FL118, another CPT derivative, with a focus on overcoming resistance to irinotecan. Methods: The effects of FL118 on CRC cells were evaluated, and bioinformatics analysis was performed on RNA-seq data. Transfection was conducted to observe the knockdown effect of survivin, and the in vivo efficacy of FL118 was assessed using a xenograft model. Results: FL118 induces apoptosis, G2/M arrest, and DNA damage. A notable mechanism of action of FL118 is a reduction in survivin levels, which downregulates the expression of RAD51, a key marker of homologous recombination, and attenuates DNA repair processes. Given that SN38 is the active metabolite of irinotecan, FL118 reduces cell viability and RAD51 in SN38-resistant LOVO cells. Conclusions: Our findings provide effective insights into the antitumor activity of FL118 and its potential as a therapeutic agent for overcoming irinotecan resistance in CRC.

Preparation irinotecan hydrochloride loaded PEGylated liposomes using novel method supercritical fluid and condition optimized by Box–Behnken design

A semi-synthetic camptothecin derivative known as irinotecan hydrochloride is frequently used to treat colorectal cancer, including colorectal adenocarcinoma and lung cancers involving small cells. Irinotecan has a very short half-life; therefore, continuous infusions are required to keep the drug’s blood levels at therapeutic levels, which could produce cumulative toxicities. Effective delivery techniques, including liposomes, have been developed to address these shortcomings. In this study, a continuous supercritical fluid approach dubbed Expansion Supercritical Fluid into an aqueous solution, in which the pressure decreases rapidly but remains over the critical pressure, is proposed to manufacture polyethylene glycolylated (PEGylated) liposomes carrying irinotecan hydrochloride. To accomplish this, PEGylated liposomes were created using a Box–Behnken design, and the operating parameters (flow rate, temperature, and pressure drop) were optimized. Encapsulation efficiency, mean size, and prepared liposome count were 94.6%, 55 nm, and 758 under ideal circumstances. Additionally, the stability of the PEGylated liposome was investigated during 8 weeks, and also PEGylated liposome-loaded irinotecan release profile was compared to conventional liposomes and free irinotecan, and a constant drug release was seen after the first burst release from liposomes.

Design, synthesis and cytotoxic activity of sulfonylated derivatives of camptothecin

With the intention of advancing our research on diverse C-20 derivatives of camptothecin (CPT), 38 CPT derivatives bearing sulphonamide and sulfonylurea chemical scaffolds and different substituent groups have been designed, synthesised and evaluated in vitro for cytotoxicity against four tumour cell lines, A-549 (lung carcinoma), KB (nasopharyngeal carcinoma), MDA-MB-231 (triple-negative breast cancer) and KBvin (an MDR KB subiline). As a result, all the synthesised compounds showed promising in vitro cytotoxic activity against the four cancer cell lines tested, and were more potent than irinotecan. Importantly, compounds 12b, 12f, 12j and 13 l possessed better antiproliferative activity against all tested tumour cell lines with IC50 values of 0.0118 − 0.5478 μM, and resulted approximately 3 to 4 times more cytotoxic than topotecan against multidrug-resistant KBvin subline. Convincing evidences are achieved that incorporation of sulphonamide and sulfonylurea motifs into position-20 of camptothecin confers markedly enhanced cytotoxic activity against cancer cell lines.

Identification of 7-aminourea or 7-aminothiourea derivatives of camptothecin as selective topoisomerase I inhibitors with anti-colorectal cancer activities

Colorectal cancer (CRC) remains one of the most prevalent malignant tumors of the digestive system, yet the availability of safe and effective chemotherapeutic agents for clinical use remains limited. Camptothecin (CPT) and its derivatives, though approved for cancer treatment, have encountered significant challenges in clinical application due to their low bioavailability and high systemic toxicity. Strategic modification at the 7-position of CPT enables the development of novel CPT derivatives with high activity. In the present study, a series of compounds incorporating aminoureas, amino thioureas, and acylamino thioureas as substituents at the 7-position were screened. These compounds were subsequently evaluated for their cytotoxicity against the human gastric cancer (GC) cell line AGS and the CRC cell line HCT116. Two derivatives, XSJ05 (IC50 = 0.006 ± 0.003 μM) and XSJ07 (IC50 = 0.013 ± 0.003 μM), exhibited remarkably effective anti-CRC activity, being better than TPT. In addition, they have a better safety profile. In vitro mechanistic studies revealed that XSJ05 and XSJ07 exerted their inhibitory effects on CRC cell proliferation by suppressing the activity of topoisomerase I (Topo I). This suppression triggers DNA double-strand breaks, leads to DNA damage and subsequently causes CRC cells to arrest in the G2/M phase. Ultimately, the cells undergo apoptosis. Collectively, these findings indicate that XSJ05 and XSJ07 possess superior activity coupled with favorable safety profiles, suggesting their potential as lead compounds for the development of CRC therapeutics.

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Topotecan and Ginkgolic Acid Inhibit the Expression and Transport Activity of Human Organic Anion Transporter 3 by Suppressing SUMOylation of the Transporter.

Organic anion transporter 3 (OAT3), expressed at the basolateral membrane of kidney proximal tubule cells, facilitates the elimination of numerous metabolites, environmental toxins, and clinically important drugs. An earlier investigation from our laboratory revealed that OAT3 expression and transport activity can be upregulated by SUMOylation, a post-translational modification that covalently conjugates SUMO molecules to substrate proteins. Topotecan is a semi-synthetic derivative of the herbal extract camptothecin, approved by the FDA to treat several types of cancer. Ginkgolic acid (GA) is one of the major components in the extract of Ginkgo biloba leaves that has long been used in food supplements for preventing dementia, high blood pressure, and supporting stroke recovery. Both topotecan and GA have been shown to affect protein SUMOylation. In the current study, we tested our hypothesis that topotecan and GA may regulate OAT3 SUMOylation, expression, and transport function. Our data show that the treatment of OAT3-expressing cells with topotecan or GA significantly decreases the SUMOylation of OAT3 by 50% and 75%, respectively. The same treatment also led to substantial reductions in OAT3 expression and the OAT3-mediated transport of estrone sulfate, a prototypical substrate. Such reductions in cell surface expression of OAT3 correlated well with an increased rate of OAT3 degradation. Mechanistically, we discovered that topotecan enhanced the association between OAT3 and the SUMO-specific protease SENP2, a deSUMOylation enzyme, which contributed to the significant decrease in OAT3 SUMOylation. In conclusion, this study unveiled a novel role of topotecan and GA in inhibiting OAT3 expression and transport activity and accelerating OAT3 degradation by suppressing OAT3 SUMOylation. During comorbidity therapies, the use of topotecan or Ginkgo biloba extract could potentially decrease the transport activity of OAT3 in the kidneys, which will in turn affect the therapeutic efficacy and toxicity of many other drugs that are substrates for the transporter.

Biological impact and therapeutic potential of a novel camptothecin derivative (FLQY2) in pancreatic cancer through inactivation of the PDK1/AKT/mTOR pathway

BackgroundCamptothecin (CPT), a pentacyclic alkaloid with antitumor properties, is derived from the Camptotheca acuminata. Topotecan and irinotecan (CPT derivatives) were first approved by the Food and Drug Administration for cancer treatment over 25 years ago and remain key anticancer drugs today. However, their use is often limited by clinical toxicity. Despite extensive development efforts, many of these derivatives have not succeeded clinically, particularly in their effectiveness against pancreatic cancer which remains modest. Aim of the studyThis study aimed to evaluate the therapeutic activity of FLQY2, a CPT derivative synthesized in our laboratory, against pancreatic cancer, comparing its efficacy and mechanism of action with those of established clinical drugs. MethodsThe cytotoxic effects of FLQY2 on cancer cells were assessed using an MTT assay. Patient-derived organoid (PDO) models were employed to compare the sensitivity of FLQY2 to existing clinical drugs across various cancers. The impact of FLQY2 on apoptosis and cell cycle arrest in Mia Paca-2 pancreatic cancer cells was examined through flow cytometry. Transcriptomic and proteomic analyses were conducted to explore the underlying mechanisms of FLQY2′s antitumor activity. Western blotting was used to determine the levels of proteins regulated by FLQY2. Additionally, the antitumor efficacy of FLQY2 in vivo was evaluated in a pancreatic cancer xenograft model. ResultsFLQY2 demonstrated (1) potent cytotoxicity; (2) superior tumor-suppressive activity in PDO models compared to current clinical drugs such as gemcitabine, 5-fluorouracil, cisplatin, paclitaxel, ivosidenib, infinitinib, and lenvatinib; (3) significantly greater tumor inhibition than paclitaxel liposomes in a pancreatic cancer xenograft model; (4) robust antitumor effects, closely associated with the inhibition of the TOP I and PDK1/AKT/mTOR signaling pathways. In vitro studies revealed that FLQY2 inhibited cell proliferation, colony formation, induced apoptosis, and caused cell cycle arrest at nanomolar concentrations. Furthermore, the combination of FLQY2 and gemcitabine exhibited significant inhibitory and synergistic effects. ConclusionThe study confirmed the involvement of topoisomerase I and the PDK1/AKT/mTOR pathways in mediating the antitumor activity of FLQY2 in treating Mia Paca-2 pancreatic cancer. Therefore, FLQY2 has potential as a novel therapeutic option for patients with pancreatic cancer.

Abstract CT155: Trial in progress: A phase Ia/Ib, an open-label, multicenter study of ZL-1310 to evaluate the safety, tolerability, and pharmacokinetics in subjects with small cell lung cancer

Abstract Background: ZL-1310, a novel antibody-drug conjugate (ADC) targeting delta-like protein 3 (DLL3) with a camptothecin derivative as its payload via a protease-cleavable linker, employs TMALIN® (Tumor Microenvironment Activable LINker-payload) ADC technology platform. DLL3, an inhibitory Notch pathway ligand and a validated target for directed therapy, is highly expressed in more than 80% of patients with small cell lung cancer (SCLC) and also has variable expression in other neuroendocrine (NE) tumors. There remains an unmet medical need for 2nd-line SCLC, as the standard of care chemotherapy has a modest response rate of ~25%. ZL-1310 is designed to minimize payload toxicity and improve anti-tumor effectiveness. Methods: This is an open-label, multiple-dose, phase 1 study of ZL-1310 administered to subjects with relapsed/refractory (r/r) metastatic SCLC who have progressed after at least one platinum-based chemotherapy regimen. The study consists of two parts: Part 1 (dose escalation) and Part 2 (dose expansion). In Part 1, the Bayesian optimal interval (BOIN) design is employed for dose escalation, while in Part 2, patients will be randomized into two cohorts with different doses of ZL-1310 to further define safety and preliminary antitumor activity. The major inclusion criteria are as follows: (1) Subjects must have histologically or cytologically confirmed metastatic or extensive-stage SCLC with no more than 3 prior regimens in the r/r setting. (2) Subjects must have at least one measurable target lesion as defined by RECIST v1.1. (3) Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. The major exclusion criteria include: (1) Prior exposure to DLL3-targeted therapy. (2) Subjects with symptomatic or uncontrolled brain metastasis requiring concurrent treatment, impaired major organ functions, active autoimmune disease, or active infections.Part 1 Dose Escalation is recruiting subjects in the US and China. Citation Format: Afshin Dowlati, Alexander Spira, Xiaodong Shen, Yinjia Fu, Yiyuan Pan, Linda Liu, Renke Zhou, Yi-Long Wu. Trial in progress: A phase Ia/Ib, an open-label, multicenter study of ZL-1310 to evaluate the safety, tolerability, and pharmacokinetics in subjects with small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT155.

Development of an ELISA with acidification treatment for an antibody conjugate incorporating Exatecans

The successful development of Sacituzumab Govitecan and Trastuzumab Deruxtecan has made camptothecin derivatives one of the most popular payloads for antibody-drug conjugates (ADCs). Camptothecin and its derivatives all exist in a pH-dependent equilibrium between the carboxylate and lactone forms. Such transformation may lead to differences in the ratio of the two molecular forms in calibration standards and biological matrix (bio-matrix) samples, thereby leading to inaccurate conjugated antibody results. In this study, we reported an enzyme-linked immunosorbent assay (ELISA) free of the aforementioned influence for the detection of the Exatecans-conjugated antibody (conjugated SM001) in cynomolgus monkey serum. The assay was developed by first acidifying all samples with glacial acetic acid (HAc), then performing neutralization and thereafter capturing conjugated SM001 with anti-Exatecan monoclonal antibody (mAb) and detecting it with biotinylated Nectin4 (hNectin4-Bio) and horseradish peroxidase-labeled streptavidin (SA-HRP). Results showed that all tested performance parameters met the acceptance criteria. The conjugated SM001 concentrations obtained were in parallel to but slightly lower than total antibody (TAb) throughout the pharmacokinetic (PK) study, revealing that the assay strategy implemented for conjugated SM001 measurement worked well for the elimination of interference triggered by the heterogeneous existence of the lactone and carboxylate forms of Exatecan (lactone-Exatecan and carboxylate-Exatecan).

Identification and characterization of camptothecin tailoring enzymes in Nothapodytes tomentosa.

Camptothecin is a complex monoterpenoid indole alkaloid with remarkable antitumor activity. Given that two C-10 modified camptothecin derivatives, topotecan and irinotecan, have been approved as potent anticancer agents, there is a critical need for methods to access other aromatic ring-functionalized congeners (e.g., C-9, C-10, etc.). However, contemporary methods for chemical oxidation are generally harsh and low-yielding when applied to the camptothecin scaffold, thereby limiting the development of modified derivatives. Reported herein, we have identified four tailoring enzymes responsible for C-9 modifications of camptothecin from Nothapodytes tomentosa, via metabolomic and transcriptomic analysis. These consist of a cytochrome P450 (NtCPT9H) which catalyzes the regioselective oxidation of camptothecin to 9-hydroxycamptothecin, as well as two methyltransferases (NtOMT1/2, converting 9-hydroxycamptothecin to 9-methoxycamptothecin), and a uridine diphosphate-glycosyltransferase (NtUGT5, decorating 9-hydroxycamptothecin to 9-β-D-glucosyloxycamptothecin). Importantly, the critical residues that contribute to the specific catalytic activity of NtCPT9H have been elucidated through molecular docking and mutagenesis experiments. This work provides a genetic basis for producing camptothecin derivatives through metabolic engineering. This will hasten the discovery of novel C-9 modified camptothecin derivatives, with profound implications for pharmaceutical manufacture.

Abstract 3140: BL-M05D1, a novel claudin 18.2-targeting ADC, demonstrates specific potent anti-tumor efficacy in preclinical evaluation

Abstract Claudin 18.2, is a member of the tight junction protein family, and an isoform of claudin18. It is therapeutically targeted in cancer due to its limited expression in normal tissue and prevalent expression in a variety of human carcinomas. To develop a promising therapeutic anti-tumor agent, we generated BL-M05D1, an anti-Claudin 18.2-Ed-04 ADC. It is comprised of a novel, specific monoclonal antibody against Claudin 18.2 (5103F3), having a wt Fc that can mediate ADCC and CDC in vitro. BL-M05D1 is composed of (5103F3), a cathepsin B cleavable linker, and a novel topoisomerase I inhibitor agent (Ed-04). The novel Ed-04 is a derivative of the alkaloid camptothecin and mediates cell cycle arrest at the S phase and subsequent apoptosis. BL-M05D1 achieves a high drug-to-antibody-ratio (DAR=8) with a highly stable linker and is readily internalized and trafficked to lysosomal cellular compartments. The antitumor efficacy of BL-M05D1 was evaluated in xenograft tumor models. BL-M05D1 exhibited strong tumor inhibition capacity toward the human gastric cancer cell MKN-45-Claudin18.2 (#C11D) xenograft model, and human pancreatic cancer cell Patu8988s-Claudin18.2 (#C7G) xenograft model. In summary, these studies suggest BL-M05D1, a novel Claudin 18.2-targeting ADC, is potentially efficacious in the treatment of Claudin 18.2-expressing carcinomas. The clinical phase I is being undertaken to evaluate safety, dosing and observations of preliminary signs of efficacy. Citation Format: Weili Wan, Kelcey Dinkel, Austin Sanford, Shuwen Zhao, Shi Zhuo, Yong Zhang, Lan Chen, Ruigang Li, Jahan Salar Khalili, Xiao Sa, Yongqi Yan, Xuejiao Shen, Yi Zhu. BL-M05D1, a novel claudin 18.2-targeting ADC, demonstrates specific potent anti-tumor efficacy in preclinical evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3140.

Abstract 3139: BL-M11D1, a novel CD33-targeting ADC, demonstrates robust anti-tumor efficacy in preclinical evaluation

Abstract CD33, is a transmembrane receptor expressed on cells of myeloid lineage. It is therapeutically targeted in cancer due to overexpression broadly among hematopoietic malignancies including AML. To develop a promising therapeutic anti-tumor agent, we generated BL-M11D1, a CD33-Ed-04 ADC. It is built on gemtuzumab, a specific monoclonal antibody against CD33, having a wt Fc that can mediate ADCC in vitro. BL-M11D1 is composed of gemtuzumab, a cathepsin B cleavable linker, and a novel topoisomerase I inhibitor agent (Ed-04). The novel Ed-04 is a derivative of the alkaloid camptothecin and mediates cell cycle arrest at the S phase and subsequent apoptosis. BL-M11D1 achieves a high drug-to-antibody-ratio (DAR=8) with a highly stable linker and is readily internalized and trafficked to lysosomal cellular compartments. The antitumor efficacy of BL-M11D1 was evaluated in xenograft tumor models. BL-M11D1 exhibited strong tumor inhibition capacity toward the human hematopoietic malignancies engrafted xenograft models. In summary, these studies suggest BL-M11D1, a novel CD33-targeting ADC, is potentially efficacious in the treatment of CD33-expressing disease. The clinical phase I trial is being undertaken to evaluate safety, dosing and observations of preliminary signs of efficacy. Citation Format: Weili Wan, Shuwen Zhao, Shi Zhuo, Yong Zhang, Lan Chen, Ruigang Li, Jahan Salar Khalili, Xiao Sa, Yongqi Yan, Xuejiao Shen, Yi Zhu. BL-M11D1, a novel CD33-targeting ADC, demonstrates robust anti-tumor efficacy in preclinical evaluation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3139.

Abstract 2071: Pre-clinical evidence for new camptothecin-peptide conjugates in the treatment of sortilin-positive colorectal cancers

Abstract Limitations in current colorectal cancer (CRC) camptothecin (CPT)-based chemotherapy have mostly been attributed to low specificity and high systemic cytotoxic side effects. More effective therapies are therefore required to improve the clinical outcomes of patients with CRC. Here, we developed a selective and better anticancer drug delivery of CPT through conjugation to a peptide (TH19P01) that targets Sortilin (SORT1), a scavenging receptor expressed in various tumor tissues including CRC. In the current study, significant SORT1 expression was detected in various CRC cell lines as well as that of irinotecan analogs efflux pump (ABCG2) in LoVo and HT-29 cells. Considering this result, we used our proprietary peptide conjugation SORT1 technology to increase cell targeting selectivity and cell delivery efficacy of CPT analogs. Different peptide drug conjugates (PDCs) were generated linking the TH19P01 peptide to SN-38 (an irinotecan metabolite) or exatecan, which are two main CPT derivatives used in recent antibody drug conjugates (ADC) as payloads. In vitro, immunonofluorescent microscopy revealed that TH19P01 was rapidly internalized (&amp;lt;15 min) in a SORT1-positive human HT-29 CRC cell model. These PDCs also inhibited CRC cell proliferation at low nM concentrations (3-90 nM). In vivo, weekly administration of TH2101 (SN-38) and of TH2303 (exatecan) conjugates were well tolerated as they had little impact on mouse body weight but caused a more potent growth inhibition of the HT-29 CRC tumor xenograft model than did either unconjugated irinotecan or exatecan molecules. In fact, at their maximum tolerable dose, irinotecan and exatecan caused a tumor growth inhibition of only 48% and 45% whereas TH2101 and TH2303 inhibited the growth of HT-29 tumors by 83% and 91%, respectively. These results provide strong pre-clinical evidence for the future development of novel CPT PDCs therapeutics with targeting of SORT1-positive CRC cells. Citation Format: Sanjoy Das, Jean-Christophe Currie, Michel Demeule, Cyndia Charfi, Alain Zgheib, Amit Nayyar, Anh Minh Thao Nguyen, Bogdan Alexandru Danalache, Richard Beliveau, Christian Marsolais, Borhane Annabi. Pre-clinical evidence for new camptothecin-peptide conjugates in the treatment of sortilin-positive colorectal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2071.

Unleashing the Potential of Camptothecin: Exploring Innovative Strategies for Structural Modification and Therapeutic Advancements.

Camptothecin (CPT) is a potent anti-cancer agent targeting topoisomerase I (TOP1). However, CPT has poor pharmacokinetic properties, causes toxicities, and leads to drug resistance, which limit its clinical use. In this paper, to review the current state of CPT research. We first briefly explain CPT's TOP1 inhibition mechanism and the key hurdles in CPT drug development. Then we examine strategies to overcome CPT's limitations through structural modifications and advanced delivery systems. Though modifications alone seem insufficient to fully enhance CPT's therapeutic potential, structure-activity relationship analysis provides insights to guide optimization of CPT analogs. In comparison, advanced delivery systems integrating controlled release, imaging capabilities, and combination therapies via stimulus-responsive linkers and targeting moieties show great promise for improving CPT's pharmacological profile. Looking forward, multifaceted approaches combining selective CPT derivatives with advanced delivery systems, informed by emerging biological insights, hold promise for fully unleashing CPT's anti-cancer potential.

Synthesis, Characterization, Docking Studies and in vitro Response of New Camptothecin Derivatives towards Oral Squamous Cell Carcinoma

Evidence suggests heterocyclic rings as the essential component of various available chemotherapeutics. Present study was aimed to carry out the molecular docking, synthesis, characterization and response of new camptothecin derivatives (NCDs) towards OSCC cell lines. To achieve the aim of the study, new camptothecin derivatives were designed to perform molecular docking against the target protein Human DNA Topoisomerase-1 (1T8I). Molecules 2 and 3 with high docking scores were subjected to synthesis. In current investigation, NCDs were synthesized by cyclization of imino analogue (2) into a new azetidinone derivative (3) on treatment with triethylamine and chloroacetyl chloride. Synthesized NCDs were characterized using IR, NMR and mass analysis. The NCDs were further subjected to antiproliferation study using CAL-27 (OSCC), followed by in vitro DNA relaxation assay and cell cycle analysis. The results of the docking of CPT-11 against Human DNA Topoisomerase-1 Duplex (PDB ID: 1T8I) in present study revealed compound 2 and 3 exhibited high docking score among all camptothecin analogues. Present study successfully synthesized and elucidated the structures of NCD 2 and 3. The antiproliferation study results revealed that NCD 2 and NCD 3 offered an IC50 of 34.73 µg/mL and 62.5 µg/mL, respectively. The DNA relaxation assay exhibited the inhibition action of synthesized NCDs (IC50 concentration) against topoisomerase enzyme. Moreover, the cell cycle analysis revealed that both NCDs arrested cancer cells in ‘S’ phase. Though the present study highlights the potential of NCDs against oral squamous cell carcinoma, however, the present study also recommends that the synthesized NCDs must be further evaluated for preclinical and clinical significance.

QSAR studies of quinoline alkaloids camptothecin derivatives for prediction anticancer activity using linear and nonlinear methods

AbstractQuinoline alkaloid camptothecin (CPT) derivatives are compounds with a wide range of inhibitory activities and they are the basis of several groups of drugs. CPT is one of the prominent lead compounds in anticancer drug development. It inhibits DNA topoisomerase I (topo I) enzyme and has shown remarkable anticancer activity against lung, colon, rectum, ovarian, breast, and stomach cancers. Quantitative structure–activity relationship (QSAR) is basically a statistical approach correlating the response activity data with descriptors encoding chemical information. In the current research, a QSAR study was performed for modeling and predicting the anticancer activity (pIC50) of 76 CPT derivatives as an inhibitor of DNA topo I using the genetic algorithm multiple linear regression (GA‐MLR) and back propagation artificial neural network (BP‐ANN) methods. The results of this study indicate that the use of constitutional and geometrical descriptors provide good estimate for pIC50. The obtained results of statistical criteria, internal and external validation show the superiority of BP‐ANN model than GA‐MLR to predict the pIC50 values of the investigated compounds. QSAR model developed in this study can be used for design and development of novel potent CPT derivatives and for predicting their anticancer activity.

An Effective and Sensitive HPLC–MS/MS Method for Determination of Cholic Acid-Coupled Camptothecin Derivative A2 in Rat Pharmacokinetics and Tissue Distribution

An Effective and Sensitive HPLC–MS/MS Method for Determination of Cholic Acid-Coupled Camptothecin Derivative A2 in Rat Pharmacokinetics and Tissue Distribution

Synthesis and biological evaluation of novel quaternary ammonium antibody drug conjugates based on camptothecin derivatives.

Antibody drug conjugates (ADCs) have emerged as a highly promising class of cancer therapeutics, comprising antibodies, effector molecules, and linkers. Among them, DS-8201a with DXd as the effector molecule, has shown remarkable anti-tumor efficacy against solid tumors, sparking a surge of interest in ADCs with camptothecin derivatives as ADC effector molecules. In this study, we introduced and successfully constructed quaternary ammonium ADCs utilizing camptothecin derivatives WL-14 and CPTS-1 for the first time. All four ADCs displayed excellent stability under physiological conditions and in plasma, facilitating their prolonged circulation in vivo. Moreover, the four ADCs, employing Val-Cit or Val-Ala dipeptide linkers effectively achieved complete release of the effector molecules via cathepsin B. Although, the in vitro antitumor activity of these ADCs was comparatively limited, the development of quaternary ammonium ADCs based on novel camptothecin derivatives as effector molecules is still a viable and promising strategy. Significantly, our study provides valuable insights into the crucial role of linker optimization in ADCs design.

Tumor–homing peptide iRGD-conjugate enhances tumor accumulation of camptothecin for colon cancer therapy

Poor intracellular uptake of therapeutics in the tumor parenchyma is a key issue in cancer therapy. We describe a novel approach to enhance tumor targeting and achieve targeted delivery of camptothecin (CPT) based on a tumor–homing internalizing RGD peptide (iRGD). We synthesized an iRGD–camptothecin conjugate (iRGD–CPT) covalently coupled by a heterobifunctional linker and evaluated its in vitro and in vivo activity in human colon cancer cells. In vitro studies revealed that iRGD–CPT penetrated cells efficiently and reduced colon cancer cell viability to a significantly greater extent at micromolar concentrations than did the parent drug. Furthermore, iRGD–CPT showed high distribution toward tumor tissue, effectively suppressed tumor progression, and showed enhanced antitumor effects relative to the parent drug in a mouse model, demonstrating that iRGD–CPT is effective in vivo cancer treatment. These results suggest that intracellular delivery of CPT via the iRGD peptide is a promising drug delivery strategy that will facilitate the development of CPT derivatives and prodrugs with improved efficacy.