Current Medicinal Chemistry - Volume 28, Issue 39, 2021

Lung cancer is a leading cause of cancer deaths worldwide. The management of lung cancer treatment is often ineffective as a result of the development of drug resistance, reactions to treatment, drug-drug interactions or non-specific targeting of the anticancer drugs. Natural compounds show promise and potential activity in lung cancer with very few side effects. While, the combinatorial action of an anti-cancer drug with a natural compound provides synergistic action which helps boost the overall therapeutic action against cancer cells. In cancer, there is a dysregulation of apoptosis which facilitates the cancer cell to survive, resulting in progression of cancer. Many cancer drugs cause mutations of genes that regulate cancer and should kill the cancer cell but lead to chemoresistance. There are many natural compounds that could specifically target different cell signalling pathways associated with cancer progression to provide a cytotoxic effect in the target cell. The importance of these compounds is emerging in many therapies developed with dual action often including a natural compound. In this review, we present a selection of these natural compounds and how they target lung cancer cells with a focus on the cell signalling pathways. Further work is required to delineate the potential action of natural compounds in the treatment against cancer.

At present, skin cancer is considered a widespread malignancy in human beings. Among diverse population types, Caucasian populations are much more prone to this malignancy in comparison to darker skin populations due to the lack of skin pigmentation. Skin cancer is divided into malignant and non-melanoma skin cancer, which is further categorized as basal and squamous cell carcinoma. Exposure to ultraviolet radiation, chemical carcinogen (polycyclic aromatic hydrocarbons, arsenic, tar, etc.), and viruses (herpes virus, human papillomavirus, and human T-cell leukemia virus type-1) are major contributing factors to skin cancer. There are distinct pathways available through which skin cancer develops, such as the JAK-STAT pathway, Akt pathway, MAPKs signaling pathway, Wnt signaling pathway, to name a few. Currently, several targeted treatments are available, such as monoclonal antibodies, which have dramatically changed the line of treatment of this disease but possess major therapeutic limitations. Thus, many phytochemicals have been evaluated either alone or in combination with the existing synthetic drugs to overcome their limitations and have been found to play a promising role in the prevention and treatment. In this review, a complete overview of skin cancer, starting from the signaling pathways involved, newer developed drugs with their targets and limitations, along with the emerging role of natural products alone or in combination as potent anticancer agents and their molecular mechanism involved has been discussed. Apart from this, various nano-cargos have also been mentioned here, which can play a significant role in the management and treatment of different types of skin cancer.

Cancer is a multi-factorial health condition involving uncontrolled cell divisions. The disease has its roots in genetic mutation. This disease affects men, women, and even children. Chemotherapy, photodynamic, photothermal, and hormonal therapies have been used to treat this deadliest disease, but a huge percentage of patients have chances of disease recurrence or resistance. Nowadays, dysregulation in miRNAs is considered one of the key factors for the development and progression of different types of cancers as they control the expression of genes responsible for cell proliferation, growth, differentiation, and apoptosis. Dietary phytochemicals with anticancer properties have been gaining focus for cancer treatment since they have been found more effective in targeting cancer via regulating miRNAs expression. These phytochemicals have no side effects and are readily available at a low cost. Several dietary phytochemicals with regulatory effects on the expression of miRNAs have been reported, including curcumin, diallyl disulfide, 3, 30-diindolylmethane, ellagic acid, genistein, indole-3-carbinol, quercetin, resveratrol, and sulforaphane. They exert their regulatory effects against different cancers either by upregulating or downregulating different cancer signalling pathways and inhibiting their progression. Curcumin down-regulates SHH pathways, epigallocatechin-3-gallate regulates the Notch pathway and inhibits TGFβ1/SMAD signalling, and resveratrol regulates the Wnt/β-catenin pathway and carnosic acid-induced apoptosis in colon cancer cell via JAK2/STAT3 signalling pathway. The miRNAs are used for the treatment of cancer as essential modulators in cellular pathways. Therefore, identifying the miRNAs and their targets and countering them with specific phytochemicals provide a safe and effective mechanism for the treatment of cancer.

Over the past several decades, plant-derived products (phytochemicals) have been suggested to possess immense therapeutic potential. Among these phytochemicals, different flavonoids have been reported for their potent anticancer activity. To exhibit their anticancer potential, these flavonoids modulate different signaling pathways. Among these pathways, the mammalian target of rapamycin (mTOR) and associated phosphatidyl-inositol 3-kinase (PI3K)/protein kinase B (Akt) signaling cascade have been reported as a pivotal modulator of cell survival, proliferation, and death/apoptosis. Hence, targeting this cascade could be an ideal strategy to alleviate apoptosis and inhibit proliferation in different forms of cancer. The targeting of PI3K/Akt/mTOR by flavonoids have been well documented in the scientific literature. In the current study, we have studied the anticancer potential of various flavonoids, especially flavones, flavonols, and isoflavones that include apigenin, luteolin, baicalein, tangeretin, epigallocatechin- 3-gallate, genistein, and daidzein especially dealing with mTOR targeting.

Cancer is one of the leading causes of death worldwide. A slight decline in mortality has been noted, but the currently available treatment options did not give an expected outcome and are associated with several side effects resulting a substantial economic burden. The advent of plant-based treatment is rising because of its ease of use, ready availability, cost-effectiveness, and low/no toxicity. In recent years, flavonoids with their diverse physico-biological properties have gained the scientific community's attention for the treatment of various forms of cancer. Different flavonoids, especially, flavonols (quercetin, kaempferol, fisetin, and isorhamnetin), flavanones (hesperidin and naringin), and anthocyanins, have shown potent anticancer activities affecting various signaling cascades. Among those, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/ mammalian target of rapamycin (mTOR) signaling pathway is widely known to play a significant role in different physio-cellular activities, which triggers malignant transformation and is considered a key target for anticancer compounds. This pathway plays a vital role in regulating the cell cycle, metabolism, survival, and proliferation. The flavonoids exhibit their anticancer activity via different molecular pathways, including PI3K/Akt/mTOR. In the current piece of paper, our focus is to underpin the action of the above-mentioned flavonoids against different cancers, mainly covering in-vitro data, through PI3K/Akt/mTOR targeting.

Approximately 85% of all lungs cancer cases are classified as non-small cell lung cancer (NSCLC). Kirsten rat sarcoma (KRAS) viral oncogene homolog mutations frequently occur in NSCLC patients resulting in a decreased overall survival. Additionally, currently used chemotherapeutic drugs lack selectivity,and patients experience side effects. Therefore, potent therapeutic agents are urgently needed for these patients. Plant- based compounds could be a potential option to treat KRAS-mutated NSCLC. These compounds are reported to be effective against the KRAS-linked up-stream and downstream signaling pathways that are directly or indirectly linked with cell proliferation, division, and apoptosis. Additionally, plant phytochemicals also suppressed different cell cycle phases of KRAS-mutant NSCLC cells. Furthermore, phytochemicals have a wider therapeutic index compared to chemotherapeutic drugs. Therefore, phytochemicals could benefit NSCLC patients as sole agents or as a combination therapy with approved chemotherapies. The current review aims to summarize the potential benefit of natural compounds in KRAS-mutant NSCLC.

Glioblastoma Multiforme (GBM) is a poorly curable brain tumor because of its extremely invasive nature. Curcuminoids, as potential phytochemicals extracted from Curcuma Longa L., have been documented for their chemopreventive and antitumor activities against several types of malignancies. These compounds exert these effects via modulation of multiple signaling pathways and molecular targets at different stages of tumor progression, proliferation, and metastasis. In experimental studies, curcuminoids have demonstrated promising therapeutic benefits to overcome GBM. Curcuminoids have been shown to exert their anti-GBM effects through regulation of angiogenesis, apoptosis, autophagy, metastasis, invasion, as well as potential molecular targets, including receptor tyrosine kinases, Sonic Hedgehog, and NF-ΚB. This study reviews the observations regarding the impact of curcumin and its derivatives on GBM and the potential of translating the research findings into the clinic.

Hydroxamic acids are a promising class of chemical compounds with proven antitumor potential, primarily due to their ability to inhibit the activity of histone deacetylase enzymes. The analysis of modern experimental data shows a wide range of biological activities of hydroxamic acids, which make them equally worthy candidates for the fight against neuropathologies. A characteristic feature of hydroxamic acids is their ability to act simultaneously on several promising molecular targets for the correction of both neuropathologies and oncological diseases, thereby exhibiting multifunctionality. This review discusses the effect of hydroxamic acids on key parts of cancer and neurodegenerative disorders' pathogenesis. Pathological changes in the processes associated with oxidative stress, the functioning of mitochondria, and the activity of metal enzymes of the class of histone deacetylases, as the main links in the epigenetic regulation of pathological conditions, are such molecular targets.

Cervical cancer (CC) is the fourth leading cancer in women in the age group of 15-44 years globally. Experimental as well as epidemiological studies identified that type16 and 18 HPV cause 70% of precancerous cervical lesions as well as cervical cancer worldwide by bringing about genetic as well as epigenetic changes in the host genome. The insertion of the HPV genome triggers various defense mechanisms including the silencing of tumor suppressor genes as well as activation of oncogenes associated with cancer metastatic pathway. E6 and E7 are small oncoproteins consisting of 150 and 100 amino acids, respectively. These oncoproteins affect the regulation of the host cell cycle by interfering with p53 and pRb. Further, these oncoproteins adversely affect the normal functions of the host cell by binding to their signaling proteins. Recent studies demonstrated that E6 and E7 oncoproteins are potential targets for CC. Therefore, this review discusses the role of E6 and E7 oncoproteins in metastasis and drug resistance as well as their regulation, early oncogene mediated signaling pathways. This review also uncovers recent updates on molecular mechanisms of E6 and E7 mediated phytotherapy, gene therapy, immune therapy, and vaccine strategies as well as diagnosis through precision testing. Therefore, understanding the potential role of E6/E7 in metastasis and drug resistance along with targeted treatment, vaccine, and precision diagnostic strategies, could be useful for the prevention and treatment of cervical cancer.

Tumour microenvironment (TME) is a resident of a variety of cells, which are devoted to the heterogeneous population of the tumour. TME establishes a communication network for crosstalk and signalling between tumour cells, stroma, and other interstitial cells. The cross-communication drives the reprogramming of TME cells, which promote cancer progression and metastasis via diverse signalling pathways. Recently, TMEderived exosomes are recognized as critical communicators of TME cell reprogramming. This review addresses the role of TME-derived exosomes in the modulation of stroma, including reprogramming the stromal cells, ECM and tumour cell metabolism, as well as neoplastic transformation. Subsequently, we described the role of exosomes in pre-metastatic niche development, maintenance of stemness and tumour vasculature, as well as development of drug resistance. We also explored tumour-derived exosomes in precision, including diagnosis, drug delivery, and vaccine development. We discussed the currently established bioengineered exosomes as carriers for chemotherapeutic drugs, RNAi molecules, and natural compounds. Finally, we presented tetraspanin and DNA-based precision methods for the quantification of tumour-derived exosomes. Overall, TMEderived exosome-mediated reprogramming of TME and precision strategies could illuminate the potential mechanisms for targeted therapeutic intervention.

Tumor associated macrophages (TAMs), located in the tumor microenvironment (TME), play a significant role in cancer cell survival and progression. TAMs have been involved in producing immuno-suppressive TME in the tumor by generating inflammatory mediators, growth factors, cytokines, chemokines, etc. TAMs can influence the angiogenesis, metastatic behavior of tumor cells (TCs) and cause multidrug resistance. TAMs within the TME can enhance cancer cell metastasis and are stromal and perivascular. The angiogenesis is promoted at the hypoxia, and the avascular zones of TME. Differentiation states of TAMs are considered ‘plastic’ as they exhibit temporal expression of one or several phenotypes depending on local cues. Emerging cancer research depicted the epigenetic regulation of macrophage polarization (both M1s, M2s) and their potential implications to develop pharmacologic modulators and microRNAs to act as molecular switches and even to serve as targeted therapies to inhibit tumor growth. In the present article, the role of TAMs in tumor progression, angiogenesis and metastasis was discussed. In addition, key signaling cascades regulated by TAMs, which have a role in chemoresistance, were also discussed. Currently, novel pleiotropic properties of various anticancer phytomedicines are gaining importance as they assist in overcoming TAMs-induced chemoresistance. Moreover, these phytomedicines are being tested as ‘adjunct therapeutics’ along with chemotherapeutic agents, anti-angiogenic molecules, anti-metastatic compounds, and other immune-checkpoint blockers against tumor metastasis/angiogenesis. Hence, a brief note on natural products targeting TAMs was provided. In summary, this review would benefit pharmacologists and medical professionals to develop therapies to target TAMs using multi-OMICs approaches, including genomics, epigenomics, transcriptomics, and proteomics.