Brain Tumor Drug Development: Current Advances and Strategies (Part 2)

Phytochemicals from plants have provided humans with numerous health benefits. Still, the special properties of the BBB (Blood-Brain Barrier) impede their access to the targeted tissue, and therefore, prevent their therapeutic use in treating brain disorders. In response to the increasing number of fatal diseases, scientists and medical experts have created strict new therapies. The concerning rise in the incidence of fatal neurodegenerative illnesses has brought attention to the need for efficient treatment alternatives. However, the conventional medications that are used to treat them already have disadvantages that make them less than optimal. The most soughtafter alternative to traditional medications is now traditional herbal remedies, which try to offset the disadvantages of synthetic treatments. Their accessibility, cost, and, most of all, their safety and effectiveness have had a major impact on their success against some of the most serious kinds of neurological illness as well as consumer dependence. Clinical and laboratory data indicate that they offer the potential to treat stroke, Alzheimer's, Parkinson's, and other illnesses. For the treatment of neurological illnesses, researchers are considering nanosystems based on herbs to enhance the transport and bioavailability of phytochemical compounds. Neurodegenerative diseases are the primary research targets for this investigation into polyherbalism, herbalmedicinal drugs, and herbal-based nanosystems. This chapter explores phytochemicals and their potential medicinal uses.

In recent years, brain tumors have become one of the leading causes of cancer-related mortality in children. Among all brain cancers, glioblastoma (GBM) is considered one of the most aggressive and lethal malignancies in oncology. The difficulty in replicating the complex structure of the brain and its surrounding microenvironment is a major obstacle to understanding potential therapeutic methods for this condition. To overcome the challenges of treating brain tumors, researchers have focused on studying different models of brain tumors. These models offer valuable insights that can aid scientists in developing more effective treatments for brain tumors. In vitro, tumor models are essential for understanding the molecular and cellular mechanisms underlying the malignant progression of tumor blood vessels. Ex vivo tumor models involve the study of malignant tissues removed from living organisms in a controlled laboratory environment. These models utilize tissue slices, organoids, and brain tumor cell cultures. Furthermore, in vivo models can be useful for preclinical testing of potential new treatment approaches and for investigating the molecular mechanisms of brain tumors and their associated microenvironments. However, this chapter discusses brain cancer, including its types, symptoms, and diagnostic characteristics. It explains the differences in cell-signaling mechanisms between glial and non-glial brain cancers. The chapter also covers the latest advancements in the prognosis of GBM. Additionally, it includes a discussion of different types of pre-clinical models used to overcome the limitations of current therapeutic approaches, such as in vitro 2D and 3D cellular models. Furthermore, the chapter addresses in vivo animal models of brain cancer created through chemical and genetic methods, as well as ex vivo models like patient-derived models, xenografts, and organoids.

The brain tumor microenvironment (TME) is a complex and dynamic niche composed of tumor cells, immune cells, blood vessels, extracellular matrix (ECM), and signaling molecules that interact to support tumor progression, angiogenesis, and immune evasion. Targeting the TME has emerged as a promising strategy for combating brain tumors, particularly gliomas, which remain challenging to treat with conventional therapies. In this context, natural bioactive compounds have gained significant attention due to their multi-targeting abilities, biocompatibility, and reduced side effects compared to synthetic drugs. These abstract reviews key natural bioactive compounds that modulate the brain tumor microenvironment, focusing on their mechanisms of action and potential therapeutic benefits. The potential for modulating the microenvironment of brain tumors has been highlighted by recent studies on natural bioactives, which are compounds found in plants, fungi, and marine organisms. These bioactives can influence key pathways involved in tumor growth, immune evasion, angiogenesis, and metastasis. This review focuses on the mechanisms by which natural bioactives, such as curcumin, resveratrol, epigallocatechin gallate (EGCG), and cannabinoids, exert their effects on the brain tumor microenvironment. It has been demonstrated that these compounds inhibit tumor growth by modulating oxidative stress, inflammation, and signaling pathways, including MAPK, PI3K, and NF-κB. Additionally, the review discusses the challenges and future directions in translating these findings from preclinical models to clinical applications. Bioactives and their interactions with the brain tumor microenvironment provide the basis for developing new therapeutic strategies which can improve patient outcomes and reduce the side effects associated with standard treatment. 

Brain tumors, including brain metastases and gliomas, are among the worst cancers in the world due to the ineffectiveness of existing treatment techniques. Currently, many treatments are used to relieve pain and prolong survival time, including chemotherapy, radiotherapy, and surgery, although all are destructive and prolong the patient's lifespan by more than one year, and relapse is common even after effective treatment. Numerous factors contribute to the failure of cancer treatments, including physiological barriers like the Blood-Brain Tumor Barrier (BTB) and the Blood Brain Barrier (BBB), which are difficult for existing macromolecularantitumor medications to cross. These failure factors, together with the long-term success of treatment, necessitate new developments in brain tumor treatments. Nanomedicine has emerged as one of the most promising options for advancing or improving brain tumor care. Targeted drug delivery with nanoparticles has the potential to significantly reduce dosage, improve release characteristics, increase specificity and bioavailability, lengthen the shelf life, and lessen toxicity and side effects. Some nanodrugs can cross the BBB and BTB, which are major impediments to treating brain cancers. In this chapter, we will examine the current state of the art, as well as the most unique and exceptional innovations in treatment options, including a concise summary of preclinical and clinical research on nanodrugs in brain tumor therapy. 

Recent years have seen tremendous advancements in the treatment of malignant brain tumors with systemic chemotherapy, providing fresh hope for better patient outcomes. The innovative chemotherapeutic drugs, targeted treatments, and combination regimens that have shown improved effectiveness and safety profiles are the main topics of this chapter's exploration of these state-of-the-art developments. The advent of blood-brain barrier-penetrant medications, customized treatment techniques based on genetic and molecular tumor characterization, and novel delivery systems including nanocarriers and convection-enhanced delivery are notable advances. Moreover, combining immunotherapy with conventional chemotherapy is emphasized as a possible way to beat tumor resistance and enhance treatment results. The chapter also explores ways to improve medication penetration via the blood-brain barrier and the processes underlying drug resistance. This chapter provides a thorough understanding of how these developments are changing the therapy landscape for malignant brain tumors through an extensive discussion of current clinical trials and forthcoming research. The chapter offers insights into prospective new paradigms in brain tumor care as well as future research initiatives by analyzing the incorporation of these innovative medicines into clinical practice. This summary of the most recent developments highlights how systemic chemotherapy may have a significant effect on the prognosis and quality of life of patients with malignant brain tumors, opening the door to more efficient and customized treatment approaches.

A brain tumour is an uncontrolled cell proliferation, forming a mass of tissue composed of cells that grow and divide abnormally, seemingly beyond the control of the body’s normal regulatory processes. Approximately 70% of primary malignant brain tumors diagnosed each year originate from glial cells. The physiological bloodbrain barrier (BBB) impairs drug distribution to the tumour microenvironment and complicates the treatment of malignant brain tumours. Most of the conventional chemotherapeutics lack specificity and lead to serious systemic toxicity. However, nanocarriers have shown efficient therapeutic efficacy in delivering medications to the brain tumour cells. The targeting of nanocarriers to the tumour sites can be achieved by active or passive targeting. The dimensions and the physicochemical properties of the nanocarriers significantly affect brain permeability. Among various nanotools, branched PAMAM, PPL, and PPI dendrimers possess great efficacy in transporting chemotherapeutic agents across the BBB for treating brain tumours. This chapter discusses the various generations of dendrimers, their synthesis techniques, and the passive and active targeting strategies used to deliver chemotherapeutics to the tumour sites. The chapter also includes dendrimers as diagnostics and contrast agents in brain tumour diagnosis. Dendrimers have been established as remarkable in diagnosing and treating brain tumours, as they can transport the therapeutically active agents across the BBB to the cancer cells after systemic administration. Different dendrimers like PAMAM, PLL, PPI, carbosilanes, and phosphorus-based are used to develop novel therapeutics having prolonged and controlled drug release, immunotherapy, and anticancer activity. This chapter can provide remarkable guidance to scientists working on brain-targeting delivery systems.

Brain cancer remains one of the most challenging malignancies to treat, with limited therapeutic options and poor prognosis. Brain cancer, particularly gliomas, presents significant challenges due to its aggressive nature and limited treatment options. In recent years, nutraceuticals—bioactive compounds derived from food sources—have gained attention for their potential in preventing and treating various forms of cancer, including brain tumours. The growing importance of nutraceuticals in the treatment and prevention of brain cancer is examined in this chapter. Important components of nutraceuticals, like vitamins, carotenoids, polyphenols, and omega-3 fatty acids, show promise in the fight against cancer by regulating cell signalling pathways involved in tumour growth and metastasis, acting as antioxidants, and exhibiting anti-inflammatory effects. The chapter further delves into the dietary sources rich in these nutraceuticals, such as curcumin, green tea, ashwagandha, mushrooms, berberin, gasotile, and silibinin. By understanding the molecular mechanisms through which these compounds act, we can better harness their potential in integrative strategies for brain cancer management, ultimately improving patient outcomes. Understanding the molecular mechanism of action of any compounds at the cellular level is very important, as signalling proteins or proteins involved in the cell cycle can serve as therapeutic targets and also be used as biomarkers. Cell signalling proteins, such as ERK, JNK, p53, AKT, NF-kappa B, and cellular proteins CDKs, DAPK, and caspases, along with their roles, are discussed in this chapter. It also highlights the molecular changes caused by the nutraceuticals in brain cancer cell lines.