Introduction/Overview
Malignant tumors are a major disease that seriously threatens human health, and chemotherapy drugs occupy a core position in their comprehensive treatment system. Natural products have always been an important treasure trove for the development of anti-tumor drugs due to their structural diversity and unique biological activity. Vincristine (VCR), as a classic natural source anti-tumor alkaloid, has been derived from Changchun flowers since the 1960s（Catharanthus roseus）Since its discovery and application in clinical practice, it has established an unshakable position in the treatment of hematological malignancies. Its CAS number is 57-22-7, and its chemical name is 22 oxovinblastine. Changchun alkaloids exert a strong anti proliferative effect by specifically interfering with the function of microtubules, a crucial component of the cell cytoskeleton during mitosis. Despite its unique therapeutic spectrum and toxicity characteristics in clinical applications, especially when compared to other vinblastine alkaloids, its severe dose limiting toxicity, particularly in peripheral neuropathy, has always been a major challenge in clinical practice. This article aims to systematically review the chemical properties, plant sources, pharmacological activities, molecular mechanisms of action, pharmacological characteristics, and clinical application status of vincristine, and to provide prospects for its future research directions and prospects.
Chemical structure and physicochemical properties
Changchun alkaloids belong to dimeric indole alkaloids, with a molecular formula of C ₄₆ H ₅₆ N ₄ O ₁₀ and a molecular weight of 824.9720. Its structure consists of two main parts: a complex multi ring "catharanthine" unit and a "vindoline" unit, connected by carbon carbon bonds. The key difference between vinblastine and its homologue is that vinblastine is connected to a formyl group (- CHO) on the nitrogen atom of the "vindoline" moiety, while vinblastine is connected to a methyl group (- CH3). This subtle structural difference profoundly affects its biological activity, toxicity distribution, and clinical use.
From the analysis of physical and chemical properties, the lipid water partition coefficient (LogP) of vincristine is 3.6218, indicating that it has a certain degree of lipophilicity. Its topological polar surface area (TPSA) is as high as 171.1700 Å ², mainly attributed to the presence of multiple oxygen-containing and nitrogen-containing functional groups in the molecule, such as formyl, methoxy, and hydroxyl groups. A higher TPSA is usually unfavorable for passive transmembrane diffusion. Its water solubility is poor, about 0.0309 mg/mL, which poses certain challenges to formulation development. Its sulfate form is commonly used in clinical practice to increase solubility. The prediction of drug efficacy parameters shows that its blood-brain barrier permeability is low, which to some extent limits its therapeutic effect on central nervous system tumors, but may also reduce the risk of partial central neurotoxicity. In addition, its hERG inhibition risk is negative, indicating a low risk of causing QT interval prolongation in the heart; The Ames test result is 0.0, indicating that there is no mutagenicity in this testing system, providing some support for its long-term clinical safety.
Plant sources and extraction methods
Changchun alkaloids mainly come from the Apocynaceae plant Changchun flowers（Catharanthus roseus (L.) G. Don）， Also known as Riri Spring or Madagascar Changchun Flower. This plant is native to Madagascar and is now widely distributed in tropical and subtropical regions around the world. The alkaloid content in Changchun flowers is extremely low, and the content of vincristine is particularly rare, usually accounting for less than 0.0003% of the dry weight. This makes its early extraction and production costs high, and it was once known as a "more expensive than gold" medicine.
The traditional extraction and separation process is relatively complex. The general process is to collect the whole plant of Changchun flower, dry and crush it, and extract it with polar organic solvents (such as methanol or ethanol). After concentration, the extract is treated with acidic water to dissolve the alkaloids into salts, and then alkalized to free the alkaloids. The alkaloids are extracted with organic solvents such as chloroform or dichloromethane. The crude total alkali obtained needs to undergo multiple and multi-mode column chromatography (such as alumina and silica gel chromatography) for repeated separation and purification, combined with crystallization technology, in order to finally obtain high-purity vincristine. Due to the yield limitations and environmental pressures of plant sources, as well as the extremely lengthy and low yield of chemical total synthesis routes that are not economically viable, plant cell culture technology is currently mainly used in industry to produce Changchun flower alkaloids. By optimizing the composition of the culture medium, adding inducers, using a two-phase culture system, and utilizing genetic engineering to regulate the expression of key biosynthetic enzymes, the accumulation of vincristine and its precursors in cell cultures can be significantly increased, becoming an important pathway for sustainable supply.
Pharmacological activity research
The core pharmacological activity of vincristine lies in its powerful anti-tumor effect, but its effects go far beyond direct cell killing.
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Anti tumor proliferation and cell cycle arrest Changchun alkaloids are highly effective inhibitors of microtubule polymerization. It binds to the beta subunit of microtubule protein with high affinity (Ki in cattle is 85 nM), inhibits microtubule polymerization into microtubules, and promotes the depolymerization of formed microtubules. This leads to the inability of the spindle to form normally, and cell mitosis is blocked in the mid stage (M phase), thereby preventing cell division and proliferation. This effect is particularly significant for rapidly proliferating tumor cells.
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Inducing cell apoptosis Cells with cycle arrest will eventually undergo programmed cell death, also known as apoptosis. Changchun alkaloids can trigger mitochondrial apoptosis pathway by disrupting microtubule dynamics, leading to the release of cytochrome C and activation of caspase cascade reaction. Studies have also shown that it can affect the balance of Bcl-2 family proteins (such as MCL1, BCL2), promote the expression of pro apoptotic factors, inhibit anti apoptotic factors, and jointly promote the process of apoptosis.
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Inhibit tumor angiogenesis and blood flow Changchun alkaloids can disrupt the microtubule system of endothelial cells, inhibit their migration and lumen formation abilities, thereby interfering with tumor angiogenesis. In addition, it can also cause dysfunction of established tumor blood vessels, reduce tumor blood supply, and lead to ischemic necrosis within the tumor.
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The impact on tumor stem cells In recent years, studies have found that vincristine can enrich tumor cell subpopulations with stem cell like characteristics in specific contexts, such as gastric cancer. This suggests that it may promote the survival or expansion of more invasive and drug-resistant stem cell like cells by applying selective pressure, which contradicts the original intention of treatment and is one of the potential mechanisms leading to drug resistance and recurrence. It also highlights the necessity of combined targeted tumor stem cell strategies.
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Other biological effects：
- Oxidative stress and inflammation Vincristine treatment can lead to an increase in intracellular reactive oxygen species (ROS) levels, triggering oxidative stress and damaging cellular components. At the same time, it can activate inflammatory pathways such as NF - κ B and promote the release of inflammatory factors.
- calcium overload Disruption of microtubules may affect the homeostasis of intracellular calcium ions, leading to an abnormal increase in calcium ion concentration and participating in cell damage and death signaling.
- Epithelial mesenchymal transition (EMT)Evidence suggests that vincristine may induce EMT in certain tumor models, which is associated with tumor invasion, metastasis, and drug resistance.
- Peripheral neuropathic pain This is its most prominent side effect. Changchun alkaloids disrupt microtubules within neuronal axons, interfering with axonal transport, particularly the reverse transport of neurotrophic factors such as nerve growth factors, leading to sensory neuron dysfunction and pain, and in severe cases, presenting as dose limiting peripheral neuropathy.
Mechanism of action and molecular targets
The mechanism of action of camptothecin is centered around microtubules, but the biological effect network it triggers involves numerous signaling molecules and pathways. In disease models such as lymphoma, its role is closely related to multiple key target molecules:
- Direct molecular target: microtubule protein beta subunit Changchun alkaloid binds to the "Changchun alkaloid binding site" on β - tubulin, altering the conformation of tubulin, reducing its polymerization ability, and disrupting microtubule stability. This is the starting point of all its pharmacological effects.
- Cell cycle regulatory targets Microtubule disruption leads to mitotic arrest, activating spindle assembly checkpoints. Long term stagnation ultimately passed TP53 Mediated DNA damage response pathway, inducing cyclin dependent kinase inhibitors such as CDKN2A (p16INK4a) The expression and influence CDC25B The activity and localization of cell cycle regulatory proteins such as phosphatases guide cell fate towards apoptosis.
- Apoptotic regulatory network Changchun alkaloid treatment can downregulate anti apoptotic proteins MCL1 and BCL2 The expression or inactivation of it may also upregulate pro apoptotic proteins, disrupting the balance of apoptosis. transcription factor STAT3 The activation state is often suppressed, and STAT3 It is a key signaling node for the survival and proliferation of many tumor cells. nuclear factor NFKB1 Activation may have a dual effect: early activation may promote survival signals, while sustained or strong activation can induce apoptosis or inflammatory responses.
- Immune and cell recognition related targets In lymphoma, leukocyte common antigen PTPRC (CD45) May be involved in cellular signaling changes mediated by vincristine. Retinoic acid X receptor β（RXRB）As a nuclear receptor, its upregulation may be related to cell differentiation, drug metabolism, and drug resistance.
- Neuron specific targets In terms of neurotoxicity, microtubule associated proteins MAPT (Tau protein) The phosphorylation status and function of may be affected by microtubule system disorders, which are associated with axonal transport disorders and the occurrence and development of neurological disorders.
In summary, vincristine triggers a series of cascade reactions through its core microtubule inhibitory effect, involving extensive regulation of cell cycle checkpoints, apoptosis pathways, stress responses, and signal transduction networks, ultimately leading to tumor cell death and normal neuronal toxicity.
Evaluation of drug properties and pharmacokinetics
As a drug that has been on the market for decades, the pharmacological characteristics and pharmacokinetic behavior of vincristine have been extensively studied.
pharmacokinetics：
The oral absorption of vincristine is poor and irregular, so intravenous administration is strictly used in clinical practice. After intravenous injection, its three phases are eliminated: the distribution phase is rapid, the intermediate phase mainly reflects tissue binding, and the terminal phase is eliminated slowly, with a half-life of about 85 hours. It is widely distributed in the body, but consistent with predictions of low blood-brain barrier permeability, its concentration in cerebrospinal fluid is very low. Changchun alkaloids are mainly metabolized by liver cytochrome P450 3A4 (CYP3A4) enzymes and excreted in feces through bile, with less than 5% of the original drug excreted by the kidneys. The activity of its metabolites is significantly reduced. Significant inter individual pharmacokinetic differences are closely related to genetic polymorphism of CYP3A4, liver function status, and concomitant medications (especially strong inducers or inhibitors of CYP3A4).
Advantages and challenges of pharmaceutical properties：
* Advantage Strong anti-tumor activity, especially with definite therapeutic effect on hematological tumors; Clear mechanism of action; The combination of drugs with different mechanisms of action, such as DNA damaging agents and glucocorticoids, has a synergistic effect and is the cornerstone of various chemotherapy regimens, such as CHOP and VDP.
* challenge：
1. Narrow treatment window, prominent dose limiting toxicity Peripheral neuropathy is its main toxicity, with dose accumulation. In severe cases, it can lead to numbness, pain, muscle weakness, disappearance of tendon reflexes, and even paralytic intestinal obstruction in the hands and feet. Bone marrow suppression is relatively mild compared to its homologue vinblastine, but it still occurs.
2. Drug resistance issue Tumor cells can develop drug resistance through various mechanisms, including: ① overexpression of drug efflux pumps, such as P-glycoprotein (P-gp/ABCB1), which pumps drugs out of cells; ② Changes or mutations in the expression of β - tubulin subtypes can reduce their affinity for drugs; ③ Adaptive changes in microtubule dynamics; ④ Defects in the apoptotic pathway.
3. Significant pharmacokinetic variability The interaction between liver function and drugs significantly affects their exposure and toxicity risk.
4. Stability of formulations It is sensitive to light and heat, and the solution needs to be stored and used away from light.
To improve its pharmacological properties, research has focused on novel delivery systems, such as liposomal vincristine (Marqibo) ®）。 This formulation changes the distribution of drugs in the body by encapsulating them in a lipid bilayer, prolongs circulation time, increases drug accumulation at the tumor site, and may reduce exposure to normal nerve tissue. Clinical evidence shows that it improves efficacy while also improving neurotoxicity.
Clinical application prospects and prospects
Changchun alkaloids are currently an important component of first-line chemotherapy drugs for the treatment of various malignant tumors in children and adults, including acute lymphoblastic leukemia (ALL, especially childhood ALL), Hodgkin's and non Hodgkin's lymphoma, nephroblastoma, neuroblastoma, etc. It has also been applied or is in the research stage in solid tumors such as melanoma, gastric cancer, and sarcoma.
Looking ahead to the future, the research and development of vincristine will focus on the following directions:
1. Overcoming drug resistance The clinical efficacy of combining P-gp inhibitors (such as verapamil) is limited and toxicity is increased. Future strategies include developing Changchun alkaloid derivatives that are insensitive to P-gp, or combining them with drugs targeting novel resistance pathways. Research on microtubule heterogeneity may also guide personalized medication.
2. Precise management of neurotoxicity Conduct in-depth research on the molecular mechanisms of neurotoxicity and search for biomarkers that can predict toxicity, such as specific neuronal proteins and genetic markers. Developing a combination of neuroprotective agents (such as neurotrophic factors, antioxidants, calcium channel modulators) and vincristine is key to improving patients' quality of life.
3. Innovative drug delivery system In addition to the already marketed liposomes, new delivery platforms such as polymer nanoparticles and antibody conjugated drugs (ADCs) are being explored. These systems aim to achieve tumor targeted delivery, increase local tumor concentration, and reduce systemic exposure, especially to the nervous system.
4. Mechanism based combination therapy Reasonably combining vincristine with other drugs targeting different sites of microtubules (such as paclitaxel), targeting apoptosis pathways (such as BCL-2 inhibitor Venetoclax), targeting DNA repair pathways, or immune checkpoint inhibitors (PD-1/PD-L1 antibodies) is an important way to improve efficacy and overcome drug resistance. Its role in regulating the tumor microenvironment, such as blood vessels and immune cells, also provides a theoretical basis for combination therapy.
5. Expand new indications Continue to explore its potential value in more solid tumors and autoimmune diseases based on its immune cell suppressive effects.
Conclusion
As a modern anti-cancer star molecule derived from traditional medicinal plants, the discovery and application of vincristine is a successful example of natural product drug research. It relies on microtubule proteins as the cornerstone of action, and by interfering with the dynamics of the cytoskeleton, triggers a series of complex cellular biological events, ultimately effectively killing tumor cells. Although its significant peripheral neurotoxicity limits clinical dosage and treatment duration, it has established a core position in the treatment of various malignant tumors, especially hematological tumors, through decades of clinical practice and in-depth research. Faced with the ongoing challenges of drug resistance and toxicity, future research is moving towards precision, intelligence, and collaboration. Through the development of new delivery systems, exploration of combination therapy strategies, in-depth analysis of toxicity mechanisms, and search for protective measures, the classic drug vincristine is expected to bring new vitality and continue to provide more effective and safer treatment options for cancer patients. Its research and development process continues to inspire us that in-depth exploration and modernization of natural products remain an inexhaustible source of innovative drug discovery.
