Organosulphur Compounds Induce Apoptosis and Cell Cycle Arrest in Cervical Cancer Cells via Downregulation of HPV E6 and E7 Oncogenes

Caspase-driven cancer therapies: Navigating the bridge between lab discoveries and clinical applications

Apoptosis is the cell's natural intrinsic regulatory mechanism of normal cells for programmed cell death, which plays an important role in cancer as a classical mechanism of tumor cell death causing minimal inflammation without causing damage to other cells in the vicinity. Induction of apoptosis by activation of caspases is one of the primary targets for cancer treatment. Over the years, a diverse range of natural, synthetic, and semisynthetic compounds and their derivatives have been investigated for their caspase-mediated apoptosis-induced anticancer activities. The review aims to compile the preclinical evidence and highlight the critical mechanistic pathways related to caspase-induced cell apoptosis in cancer treatment. The focus is placed on the key components of the mechanisms, including their chemical nature, and specific attention is given to phytochemicals derived from natural sources and synthetic and semisynthetic compounds. 180+ compounds from the past two decades with potential as anticancer agents are discussed in this review article. By summarizing the current knowledge and advancements in this field, this review provides a comprehensive overview of potential therapeutic strategies targeting apoptosis in cancer cells. The findings presented herein contribute to the ongoing efforts to combat cancer and stimulate further research into the development of effective and targeted anticancer therapies.

Anticancer activity of broccoli, its organosulfur and polyphenolic compounds

The use of natural bioactive constituents from various food sources for anticancer purposes has become increasingly popular worldwide. Broccoli (Brassica oleracea var. italica) is on the top of the consumed vegetables by the masses. Its raw matrix contains a plethora of phytochemicals, such as glucosinolates and phenolic compounds, along with rich amounts of vitamins, and minerals. Consumption of broccoli-derived phytochemicals provides strong antioxidant effects, particularly due to its sulforaphane content, while modulating numerous molecules involved in cell cycle regulation, control of apoptosis, and tuning enzyme activity. Thus, the inclusion of broccoli in the daily diet lowers the susceptibility to developing cancers. Numerous studies have underlined the undisputable role of broccoli in the diet as a chemopreventive raw food, owing to the content in sulforaphane, an isothiocyanate produced as a result of hydrolysis of precursor glucosinolates called glucoraphanin. This review will provide evidence supporting the specific role of fresh florets and sprouts of broccoli and its key bioactive constituents in the prevention and treatment of different cancers; a number of studies carried out in the in vitro and in vivo conditions as well as clinical trials were analyzed.

Carvacrol instigates intrinsic and extrinsic apoptosis with abrogation of cell cycle progression in cervical cancer cells: Inhibition of Hedgehog/GLI signaling cascade

Recent times have seen a strong surge in therapeutically targeting the hedgehog (HH)/GLI signaling pathway in cervical cancer. HH signaling pathway is reported to be a crucial modulator of carcinogenesis in cervical cancer and is also associated with recurrence and development of chemoresistance. Moreover, our previous reports have established that carvacrol (CAR) inhibited the proliferation of prostate cancer cells via inhibiting the Notch signaling pathway and thus, it was rational to explore its antiproliferative effects in cervical cancer cell lines. Herein, the present study aimed to investigate the anticancer and apoptotic potential of CAR on C33A cervical cancer cells and further explore the underlying mechanisms. We found that CAR significantly suppressed the growth of C33A cells, induced cell cycle arrest, and enhanced programmed cell death along with augmentation in the level of ROS, dissipated mitochondrial membrane potential, activation of caspase cascade, and eventually inhibited the HH signaling cascade. In addition, CAR treatment increased the expression of pro-apoptotic proteins (Bax, Bad, Fas-L, TRAIL, FADDR, cytochrome c) and concomitantly reduced the expression of anti-apoptotic proteins (Bcl-2 and Bcl-xL) in C33A cells. CAR mediates the activation of caspase-9 and -3 (intrinsic pathway) and caspase-8 (extrinsic pathway) accompanied by the cleavage of PARP in cervical cancer cells. Thus, CAR induced apoptosis by both the intrinsic and extrinsic apoptotic pathways. CAR efficiently inhibited the growth of cervical cancer cells via arresting the cell cycle at G0/G1 phase and modulated the gene expression of related proteins (p21, p27, cyclin D1 and CDK4). Moreover, CAR inhibited the HH/GLI signaling pathway by down regulating the expression of SMO, PTCH and GLI1 proteins in cervical carcinoma cells. With evidence of the above results, our data revealed that CAR treatment suppressed the growth of HPV^-C33A cervical cancer cells and further elucidated the mechanistic insights into the functioning of CAR.

Diallyl Disulfide: A Bioactive Garlic Compound with Anticancer Potential

Cancer is a life-threatening disease caused by the uncontrolled division of cells, which culminates in a solid mass of cells known as a tumor or liquid cancer. It is the leading cause of mortality worldwide, and the number of cancer patients has been increasing at an alarming rate, with an estimated 20 million cases expected by 2030. Thus, the use of complementary or alternative therapeutic techniques that can help prevent cancer has been the subject of increased attention. Garlic, the most widely used plant medicinal product, exhibits a wide spectrum of biological activities, including antibacterial, hypo-lipidemic, antithrombotic, and anticancer effects. Diallyl disulfide (DADS) is a major organosulfur compound contained within garlic. Recently, several experimental studies have demonstrated that DADS exhibits anti-tumor activity against many types of tumor cells, including gynecological cancers (cervical cancer, ovarian cancer), hematological cancers (leukemia, lymphoma), lung cancer, neural cancer, skin cancer, prostate cancer, gastrointestinal tract and associated cancers (esophageal cancer, gastric cancer, colorectal cancer), hepatocellular cancer cell line, etc. The mechanisms behind the anticancer action of DADS include epithelial-mesenchymal transition (EMT), invasion, and migration. This article aims to review the available information regarding the anti-cancer potential of DADS, as well as summarize its mechanisms of action, bioavailability, and pharmacokinetics from published clinical and toxicity studies.

Phytocompounds from the medicinal and dietary plants: Multi-target agents for cancer prevention and therapy

Cervical cancer is the fourth leading cause of cancer death among women worldwide. Due to cervical cancer's high incidence and mortality, there is an unmet demand for effective diagnostic, therapeutic, and preventive agents. At present, the preferred treatment strategies for advanced metastatic cervical cancer include surgery, radiotherapy, and chemotherapy. However, cervical cancer is gradually developing resistance to chemotherapy, thereby reducing its efficacy. Over the last several decades, phytochemicals, a general term for compounds produced from plants, have gained attention for their role in preventing cervical cancer. This role in cervical cancer prevention has garnered attention on the medicinal properties of fruits and vegetables. Phytochemicals are currently being evaluated for their ability to block proteins involved in carcinogenesis and chemoresistance against cervical cancer. Chemoresistance to cancer drugs like cisplatin, doxorubicin, and 5-fluorouracil has become a significant limitation of drug-based chemotherapy. However, the combination of cisplatin with other phytochemicals has been identified as a promising alternative to subjugate cisplatin resistance. Phytochemicals are promising chemo-preventive and chemotherapeutic agents as they possess antioxidant, anti-inflammatory, and anti-proliferative potential against many cancers, including cervical cancer. Furthermore, the ability of the phytochemicals to modulate cellular signaling pathways through up and down regulation of various proteins has been claimed for their therapeutic potential. Phytochemicals also display a wide range of biological functions, including cell cycle arrest, apoptosis induction, inhibition of invasion, and migration in cervical cancer cells. Numerous studies have revealed the critical role of different signaling proteins and their signaling pathways in the pathogenesis of cervical cancer. Here, we review the ability of several dietary phytochemicals to alter carcinogenesis by modulating various molecular targets.

Antiproliferative and apoptotic potential of Glycyrrhizin against HPV16+ Caski cervical cancer cells: A plausible association with downreguation of HPV E6 and E7 oncogenes and Notch signaling pathway

Cervical cancer (CCa) is the second most frequent carcinoma in females and human papilloma virus (HPV) oncoproteins are regarded as one of the critical etiological agent. Despite recent advances in screening and management of CCa, still it remains the deadliest carcinoma as advanced and metastatic stages are mostly incurable. This urges for the development of newer therapeutic interventions. The current was aimed to investigate the antiproliferative and apoptotic potential of glycyrrhizin (Gly) against HPV16⁺ CaSki CCa cells. Our findings substantiated that Gly exerted antiproliferative effects on the CaSki cells by obstructing their proliferation rate. Gly substantially enhanced apoptosis in Caski cells in a dose-dependent manner via augmenting the generation of ROS, DNA fragmentation and disruption of the mitochondrial membrane potential. Gly mediated apoptosis in CaSki cells was found to be due to activation of caspase-8 and capsase-9 along with the modulation of pro-and anti-apoptotic gene expression. Moreover, Gly halts the progression of CaSki cells at G₀/G₁ phase which was found to be due to reduced expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4) along with the enhanced expression of CDK inhibitor p21^Cip1. Further, Gly downregulates the expression of HPV oncoproteins (E6 & E7) along with the inhibition of Notch signaling pathway. Taken together, Gly represents as a potential therapeutic modality for CCa which could rapidly be translated for clinical studies.

HPV-induced cancers: preclinical therapeutic advancements

INTRODUCTION

High-risk HPV infections are related to several epithelial cancers. Despite the availability of prophylactic vaccines, HPV infections are still responsible for about 5% of all human malignancies worldwide. While therapeutic vaccines are ongoing clinical trials, genotoxic agents and surgical interventions represent current clinical treatments, with no specific anti-HPV drugs yet available in the clinics.

AREAS COVERED

We offer a comprehensive report of small molecules in preclinical studies proposed as potential anticancer agents against HPV-driven tumors. Given the importance of HPV oncoproteins for cancer maintenance, particularly E6 and E7, we present a classification of both non-targeted and targeted agents, with a further subdivision of the latter into two categories according to their either direct or indirect activity against viral protein functions.

EXPERT OPINION

Prophylactic vaccines can prevent the insurgence of HPV-related cancers, but have no effect against pre-existing infections. Moreover, their high cost, genotype-restricted effect and the growing worldwide distrust for vaccines make the availability of a specific drug an unmet medical need. Different viral early proteins emerge as ideal candidates for drug development. We highlight the most promising strategies and address future challenges in this field to herald the prospect of a specific therapeutic regimen against HPV-related cancers.

Biological Functions of Diallyl Disulfide, a Garlic-Derived Natural Organic Sulfur Compound

Garlic is widely accepted as a functional food and an excellent source of pharmacologically active ingredients. Diallyl disulfide (DADS), a major bioactive component of garlic, has several beneficial biological functions, including anti-inflammatory, antioxidant, antimicrobial, cardiovascular protective, neuroprotective, and anticancer activities. This review systematically evaluated the biological functions of DADS and discussed the underlying molecular mechanisms of these functions. We hope that this review provides guidance and insight into the current literature and enables future research and the development of DADS for intervention and treatment of multiple diseases.

A Comparative Antibacterial, Antioxidant, and Antineoplastic Potential of Rauwolfia serpentina (L.) Leaf Extract with Its Biologically Synthesized Gold Nanoparticles (R-AuNPs)

Rauwolfia serpentina (R. serpentina), belonging to the family Apocynaceae, is a renowned medicinal herb for its different pharmacological activities such as antibacterial, antifungal, anti-inflammatory, and antiproliferative characteristics. This study has done a comparative assessment of the antibacterial, antioxidant, and anti-cancer activity of R. serpentina aqueous leaf extract (RSALE) with encapsulated gold nanoparticles (R-AuNPs). The R-AuNPs are prepared so that they are significant in size, monodispersed, and extremely stable. Their characterization was done by numerous parameters, including UV-visible spectroscopy (528 nm), transmission electron microscopy (~17 d. nm), dynamic light scattering (~68 d. nm), and zeta-potential (~-17 mV). Subsequently, a potent antibacterial activity was depicted via RSALE and R-AuNPs when examined by disc diffusion against various Gram-positive and Gram-negative bacterial strains. The obtained zones of inhibition of RSALE (100 mg/mL) were 34 ± 0.1, 35 ± 0.1, 28.4 ± 0.01, and 18 ± 0.01, although those of R-AuNPs (15 mg/mL) were 24.4 ± 0.12, 22 ± 0.07, 20 ± 0.16, and 17 ± 0.3 against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (MTCC 8114), and Streptococcus pyogenes (ATCC 19615), respectively. However, no zone of inhibition was obtained when tested against Proteus vulgaris (MTCC 1771). Furthermore, the obtained MIC values for Staphylococcus aureus were 0.91, 0.61, and 1.15 mg/mL; for Escherichia coli, 0.79, 0.36, and 1.02 mg/mL; for Bacillus subtilis 0.42, 0.27, and 0.474 mg/mL; and for Streptococcus pyogenes, 7.67, 3.86, and 8.5 mg/mL of pure RSALE, R-AuNPs, and Amoxicillin (control), respectively, incorporating that R-AuNPs have been shown to have a 1.4-fold, 2.1-fold, 1.5-fold, and 1.9-fold enhanced antibacterial activity in contrast to pure RSALE tested against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Streptococcus pyogenes, and Proteus vulgaris, respectively. Additionally, an enhanced antioxidant potential was detected in R-AuNPs compared to RSALE evaluated by the 2,2-Diphenyl-1-Picryl Hydrazyl Radical Scavenging (DPPH) Ferric reducing antioxidant power (FRAP) assay. The determined IC 50 values of RSALE and R-AuNPs were 0.131 ± 0.05 and 0.184 ± 0.02 mg/mL, and 0.110 ± 0.1 and 0.106 ± 0.24 mg/mL via the FRAP and DPPH assays, respectively. In addition, the anti-cancer activity against the human cervical cancer (Hela) cell line was evaluated, and the MTT assay results revealed that R-AuNPs (IC50 88.3 µg/mL) had an enhanced anti-cancer potential in contrast to RSALE (171.5 µg/mL). Subsequently, the findings of this study indicated that R. serpentina leaves and their nanoformulation can be used as a potent source for the treatment of the above-mentioned complications and can be used as a possible agent for novel target-based therapies for the management of different ailments.

Prostate Apoptotic Induction and NFκB Suppression by Dammarolic Acid: Mechanistic Insight into Onco-Therapeutic Action of an Aglycone Asiaticoside

Prostate cancer (PCa) is addressed as the second most common form of onco-threat worldwide and is usually considered as the major cause of mortality in men. Recent times have seen a surge in exploration of plant-derived components for alternative therapeutical interventions against different oncological malignancies. Dammarolic acid or Asiatic acid (AsA) is an aglycone asiaticoside that has been reported for its efficacy in several ailments including cancer. The current study aimed to investigate the anti-proliferative potency of AsA against human prostate cancer PC-3 cells. Purified AsA was diluted and PC-3 cells were exposed to 20, 40, and 80 µM concentration and incubated for 24 h. Post-exposure, PC-3 cells showcased a substantial loss of their viability at 20 µM (p < 0.05), moreover, this reduction in cell viability escalated proportionally with an increase in AsA at concentrations of 40 and 80 µM (p < 0.01; p < 0.001) respectively. AsA-impelled loss of cellular viability was also evident from the acridine orange-stained photomicrographs, which was also used to quantify the viable and apoptotic cells using Image J software. Additionally, quantification of ROS within PC-3 cells also exhibited an increase in DCF-DA-mediated fluorescence intensity post-exposure to AsA in a dose-dependent manner. AsA-induced apoptosis in PC-3 cells was shown to be associated with augmented activity of caspase-3 proportionally to the AsA concentrations. Thus, initially, this exploratory study explicated that AsA treatment leads to anti-proliferative effects in PC-3 cells by enhancing oxidative stress and inciting apoptosis en route to onset of nuclear fragmentation.

Efficacy of SPG-ODN 1826 Nanovehicles in Inducing M1 Phenotype through TLR-9 Activation in Murine Alveolar J774A.1 Cells: Plausible Nano-Immunotherapy for Lung Carcinoma

Alveolar macrophages are the first line of defense against intruding pathogens and play a critical role in cancer immunology. The Toll-like receptor (TLR) family mediates an important role in recognizing and mounting an immune response against intruding microbes. TLR-9 is a member of the intracellular TLR family, which recognizes unmethylated CG motifs from the prokaryotic genome. Upon its activation, TLR-9 triggers downstream of the MyD-88-dependent transcriptional activation of NF-κB, and subsequently results in abundant inflammatory cytokines expression that induces a profound inflammatory milieu. The present exploratory investigation aimed at elucidating the potency of schizophyllan for entrapping ODN 1826 (SPG-ODN 1826)-mediated stimulation of TLR-9 in provoking an inflammatory-type response in murine alveolar macrophages. Schizophyllan (SPG), a representative of the β-glucan family, was used in the present study as a nanovehicle for endosomal trafficking of CpG ODN 1826. TEM analysis of SPG-ODN 1826 nanovehicles revealed that the prepared nanovehicles are spherical and have an average size of about 100 nm. Interestingly, SPG-ODN 1826 nanovehicles were competent in delivering their therapeutic payload within endosomes of murine alveolar macrophage (J774A.1) cells. Exposure of these nanovehicles within LPS stimulated J774A.1, resulted in a significant provocation of reactive oxygen species (ROS) (p < 0.01) in comparison to CpG ODN 1826 alone. Moreover, the formulated nanovehicles succeeded in generating a profound Th1-based cytokine profile constituted by enhanced expression of IFN-γ (p < 0.001) and IL-1β (p < 0.001) inflammatory cytokines. These findings clearly indicated the immunostimulatory potential of SPG-ODN 1826 nanovehicles for inducing the Th1-type phenotype, which would certainly assist in skewing M2 phenotype into the much-desired M1 type during lung cancer.

Glycyrrhizin Mediates Downregulation of Notch Pathway Resulting in Initiation of Apoptosis and Disruption in the Cell Cycle Progression in Cervical Cancer Cells

Growing emphasis on exploring the antiproliferative potential of natural compounds has gathered momentum for the formulation of anticancer drugs. In the present study, the anticancer and apoptotic potential of glycyrrhizin (GLY) was studied on HPV^- C33A cervical cancer (CCa) cells. Our results indicated that GLY exerted antiproliferative effects in the C33A cells by inducing significant cytotoxicity. Treatment with GLY substantially increases the apoptosis in a dose-dependent manner via disrupting the mitochondrial membrane potential. GLY induced apoptosis in C33A cells via activation of capsase-9 (intrinsic pathway) and caspase-8 (extrinsic pathway) along with the modulation of pro- and antiapoptotic protein expression. Moreover, GLY also exerted cell cycle arrest in C33A cells at G₀/G₁ phase which was associated with the decreased expression of cyclin D1 and cyclin-dependent kinase 4 (CDK4) along with the increased expression of CDK inhibitor p21^Cip1. Furthermore, GLY treated CCa cells exhibited significant downregulation of Notch signaling pathway which may be associated with increased apoptosis as well as cell cycle arrest in C33A CCa cells. Thus, GLY could be an appendage in the prevention and management of CCa.

Leishmanial CpG DNA nanovesicles: A propitious prophylactic approach against visceral leishmaniasis

Unmethylated CpG motifs with phosphothioate backbone trigger TLR9 to elicit innate immune response characterized by the production of Th1 cytokines. The use of CpG DNA as an adjuvant has established its role in potentiating the humoral and cell mediated vaccine specific immune response. However, none of the synthetic oligodeoxynucleotides (ODNs) know and used till date are associated with the parasite itself. Our group identified a novel CG rich sequence of 14 base pairs from Leishmania donovani genome (Ld CpG ODN) and established it as a TLR9 agonist. The present study was designed to ascertain the adjuvanticity of Ld CpG ODN with soluble leishmanial antigen in experimental model of L. donovani. During the study Schizophyllan (SPG), a fungal polymer was used for encapsulating Ld CpG ODN for efficient endosomal delivery. The synthesized nanovehicles were of nearly 100 nm and localized within endosomes as confirmed by confocal microscopy. Immunization studies displayed the superior ability of synthesized nanovehicles co-administered with parasite antigen in augmenting innate immune response in comparison to ODN, nanoparticles or soluble antigen alone. The response included generation of ROS, NO and iNOS expression followed by proinflammatory cytokine milieu with reduced parasitic load within liver, spleen and bone marrow. These immune-tailored particles in combination with parasitic antigens elicited significant generation of cell mediated response owing to the presence of high levels of CD8⁺ T-cells and lymphocyte proliferation. Moreover, vaccination regime with synthesized adjuvant also activated humoral immunity by escalating the levels of IgG2 followed by reduced levels of anti-leishmanial IgG and IgG1 antibodies. The findings support the efficacy of Ld CpG ODN as a potential adjuvant against visceral leishmaniasis.