Nelfinavir

Regulation of MAPK, JNK, and NF-κB Pathways

The Mitogen-Activated Protein Kinase (MAPK) pathways are fundamental signaling cascades that regulate a wide array of cellular processes, including proliferation, differentiation, apoptosis, and stress responses. nih.govcreative-diagnostics.comspandidos-publications.comscienceopen.com In mammals, three main MAPK families are recognized: Extracellular-signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), and p38/stress-activated protein kinases (SAPKs). nih.govscienceopen.com Each MAPK pathway typically involves a three-tiered kinase cascade: a MAP kinase kinase kinase (MAPKKK), a MAP kinase kinase (MAPKK), and the terminal MAPK. creative-diagnostics.comscienceopen.com

This compound has been shown to influence these pathways. It can reduce the phosphorylation of MAPKs, including ERK, in various cellular contexts. plos.orgnih.govresearchgate.net For instance, in human monocyte-derived macrophages, this compound treatment decreased the phosphorylation of MAPKs, contributing to its anti-inflammatory effects. nih.govresearchgate.net Furthermore, this compound's predicted off-target bindings to various protein kinases are hypothesized to regulate cancer pathways such as MAPK and JNK. plos.org

The JNK pathway, a subfamily of MAPKs, is activated by diverse environmental stresses, inflammatory cytokines, and growth factors, playing critical roles in apoptosis, inflammation, and cell cycle regulation. nih.govnih.govpaulogentil.comanygenes.com this compound's impact on the JNK pathway has been observed, particularly in the context of endoplasmic reticulum (ER) stress. For example, this compound treatment has been found to stimulate c-Jun protein expression, a key component of the JNK/AP-1 pathway, which is involved in the transcriptional regulation of stress response genes. scienceopen.com

The Nuclear Factor-kappa B (NF-κB) pathway is a crucial regulator of immune and inflammatory responses, also playing a role in cell survival and proliferation. ashpublications.orgjci.org The NF-κB family consists of five transcription factors: p50, p52, RelA (p65), c-Rel, and RelB, which form homo- and heterodimers to modulate gene expression. ashpublications.orgjci.orgmdpi.comunibo.it Activation of the NF-κB pathway typically involves the IκB kinases (IKKs) phosphorylating inhibitory IκB proteins, leading to their degradation and subsequent nuclear translocation of NF-κB dimers. researchgate.netashpublications.orgjci.org Research findings regarding this compound's modulation of NF-κB are varied and context-dependent. While one study in human monocyte-derived macrophages indicated that this compound failed to modulate NF-κB activity, nih.gov another study demonstrated that this compound stimulated NF-κB protein expression and activity in SARS-CoV-2 infected cells, linking it to ER stress and MAPK signaling. scienceopen.com

Table 1: this compound's Reported Modulation of MAPK, JNK, and NF-κB Pathways

Impact on IGF-1R Signaling

The Insulin-like Growth Factor 1 Receptor (IGF-1R) signaling pathway is a critical network involved in cell proliferation, survival, and growth. researchgate.netuniprot.orgnih.gov IGF-1R is a receptor tyrosine kinase that, upon ligand binding (primarily IGF-1), undergoes autophosphorylation and phosphorylates various intracellular adapter proteins, including insulin-receptor substrates (IRS1/2) and Shc. researchgate.netuniprot.orgnih.gov This activation leads to the engagement of two main downstream signaling pathways: the PI3K-AKT/PKB pathway and the Ras-MAPK pathway. researchgate.netuniprot.orgnih.gov Activation of the PI3K-AKT pathway inhibits apoptosis and stimulates protein synthesis, while the Ras-MAPK pathway enhances mitogenic effects and cell survival. researchgate.netuniprot.org

This compound has been shown to significantly impact IGF-1R signaling. Research indicates that this compound can inhibit the activation of IGF-1R and its downstream Akt signaling. plos.orgtandfonline.comresearchgate.net This inhibition is consistent with this compound's observed anti-cancer effects, as the IGF-1R pathway is often hyperactive in various malignancies, promoting uncontrolled cell growth and survival. plos.orguniprot.orgnih.gov The ability of this compound to block growth factor receptor activation, including IGF-1R, suggests that it can compete with endogenous growth factors, thereby attenuating their pro-survival and proliferative signals. plos.orgtandfonline.com

Table 2: this compound's Impact on IGF-1R Signaling

Mechanisms of Cell Cycle Arrest

The cell cycle is a tightly regulated process controlled by checkpoints that ensure proper cell division. libretexts.orgkhanacademy.org Key regulators of this process are cyclins and cyclin-dependent kinases (CDKs), whose coordinated activity drives progression through different cell cycle phases. libretexts.orgkhanacademy.orgnih.govwikipedia.org

Cyclins are regulatory proteins whose levels fluctuate predictably throughout the cell cycle, while CDKs are serine/threonine kinases that become active upon binding to cyclins. libretexts.orgkhanacademy.orgnih.govwikipedia.org The activated cyclin-CDK complexes phosphorylate target proteins, thereby advancing the cell through specific cell cycle phases (G1, S, G2, M). libretexts.orgkhanacademy.orgnih.gov For instance, CDK1, CDK2, CDK3, CDK4, and CDK6 are directly involved in regulating cell cycle transitions. nih.govwikipedia.org

This compound has been shown to induce cell cycle arrest, suggesting its involvement in the regulation of cyclins and CDKs. mdpi.comresearchgate.net While specific detailed findings on this compound's direct modulation of individual cyclins and CDKs are less extensively documented in the provided search results, its ability to cause cell cycle arrest implies an upstream or direct interference with the cyclin-CDK machinery. The effects of this compound on the cell cycle are often observed as an early event during treatment, preceding the induction of cell death pathways. mdpi.com

Cell cycle inhibitors, such as p21 and p53, play crucial roles in negatively regulating cell cycle progression, often in response to cellular stress or DNA damage. libretexts.orgspandidos-publications.comnih.govahajournals.org The p21 protein (also known as WAF1/CIP1 or CDKN1A) is a universal cell cycle inhibitor, directly controlled by the tumor suppressor protein p53. spandidos-publications.comnih.govahajournals.orgembopress.org When cells experience DNA damage, p53 accumulates and activates the transcription of p21, which then inhibits the activity of cyclin-CDK complexes, leading to cell cycle arrest, particularly at the G1/S phase checkpoint. spandidos-publications.comnih.govahajournals.orgtandfonline.com Beyond inhibiting cyclin-CDK complexes, p21 can also negatively regulate the cell cycle by binding to and inhibiting the DNA polymerase δ cofactor, PCNA. ahajournals.org

Table 3: this compound's Effects on Cell Cycle and Inhibitors

Regulation of Cyclins and Cyclin-Dependent Kinases (CDKs)

Induction of Cell Death Modalities

This compound is known to induce various forms of cell death in cancer cells, highlighting its potent anti-cancer properties. These modalities include caspase-dependent apoptosis, non-apoptotic cell death, and autophagy, often linked to the induction of endoplasmic reticulum (ER) stress. tandfonline.commdpi.comresearchgate.nettandfonline.comnih.govresearchgate.net

This compound triggers typical cell death by activating caspases, such as caspase-3, -4, -8, and -9. mdpi.comtandfonline.com This caspase activation leads to the characteristic features of apoptosis. Beyond classical apoptosis, this compound also induces non-apoptotic cell death pathways. tandfonline.comtandfonline.com

A significant mechanism contributing to this compound's cell death-inducing effects is the induction of ER stress and the unfolded protein response (UPR). tandfonline.commdpi.comresearchgate.nettandfonline.comnih.gov this compound causes a sustained increase in ER stress markers, such as BiP and phospho-eIF-2α, which are associated with long-term inhibition of protein synthesis. researchgate.nettandfonline.com This ER stress can lead to a pro-apoptotic environment, signaled by increased ATF4 and CHOP, and an increased Bax/Bcl-2 ratio. researchgate.net

Furthermore, this compound induces autophagy, a cellular process involving the degradation and recycling of cellular components. tandfonline.comtandfonline.comnih.govresearchgate.net this compound may induce autophagy through multiple mechanisms, including mimicking nutrient starvation by blocking growth factor receptor signaling. tandfonline.comresearchgate.net The induction of autophagy can contribute to cell death or survival depending on the cellular context. tandfonline.com

This compound has also been shown to sensitize cancer cells to other death-inducing agents. For instance, it enhances the expression of TRAIL receptor (DR5) in p53 mutant glioblastoma cells, and when combined with TRAIL, it promotes potent transactivation of DR5, leading to significant cell death characterized by increased sub-G1 DNA content, caspase activation, and PARP cleavage. mdpi.comtandfonline.com This sensitization is mediated by ER stress-related transcription factors ATF4 and CHOP. mdpi.com

Table 4: this compound's Induction of Cell Death Modalities

Autophagy Modulation

Oxidative Stress Induction

Downregulation of Vascular Endothelial Growth Factor (VEGF) and basic Fibroblast Growth Factor (bFGF)

This compound has been demonstrated to decrease the expression and secretion of Vascular Endothelial Growth Factor (VEGF), a key mediator of angiogenesis. This reduction is attributed to a decrease in the phosphorylation of Akt and the transcription factor SP1, as well as a reduction in Hypoxia-Inducible Factor 1-alpha (HIF-1α). promega.dethermofisher.commdpi.comgenecards.orguniprot.org Both SP1 and HIF-1α are known to bind to the promoter region of VEGF and transactivate the gene. promega.de Studies have shown that this compound dramatically decreases VEGF mRNA expression and secretion under normoxic conditions. mdpi.com Functionally, this leads to a decrease in angiogenesis, as observed in in vivo Matrigel plug assays. thermofisher.comgenecards.org For instance, research in head and neck squamous cell carcinoma, lung cancer, and glioblastoma cells demonstrated reduced VEGF expression in response to this compound, which correlated with decreased angiogenesis in vivo. mesoscale.com Furthermore, this compound has been shown to downregulate basic Fibroblast Growth Factor (bFGF), another important pro-angiogenic factor. researchgate.net

Table 1: Impact of this compound on Angiogenic Factors

Inhibition of Matrix Metalloproteinases (MMP-2, MMP-9)

This compound has been observed to inhibit Matrix Metalloproteinase-2 (MMP-2) and Matrix Metalloproteinase-9 (MMP-9) activity. researchgate.net These enzymes are crucial modulators of tumor cell invasion and metastasis, as they facilitate the degradation of the extracellular matrix. promega.de Studies have indicated that HIV protease inhibitors, including this compound, have the potential to downregulate MMP-9 and MMP-2 in various cellular contexts, such as during adipocyte differentiation and in glioblastoma cells. promega.de Functionally, this inhibition has been associated with reduced cell migration, suggesting a role for this compound in impeding tumor progression and metastasis. promega.de

Table 2: Impact of this compound on Matrix Metalloproteinases

Upregulation of TRAIL Receptor DR5 and Sensitization to TRAIL

This compound induces endoplasmic reticulum (ER) stress, a cellular condition that can trigger cell death. promega.de A significant consequence of this compound-induced ER stress is the upregulation of the Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand (TRAIL) receptor DR5 (Death Receptor 5), and in some cases, DR4. This upregulation enhances the sensitivity of cancer cells to TRAIL-induced apoptosis. promega.de Research has shown that this compound increases DR5 mRNA and protein levels, a process mediated by ER stress-related transcription factors such as Activating Transcription Factor 4 (ATF4) and CCAAT/enhancer-binding protein homologous protein (CHOP). promega.de This sensitization has been observed in various cancer cell types, including ovarian, cervical, renal, and glioblastoma cells, even in those with p53 mutations, where DR5 upregulation is typically challenging. promega.de

Table 3: this compound's Modulation of TRAIL Pathway

Interaction with Heat Shock Protein 90 (HSP90)

This compound has been identified as an inhibitor of Heat Shock Protein 90 (HSP90) function through a novel mechanism. HSP90 is a molecular chaperone critical for the stability and function of numerous oncogenic signaling proteins, often referred to as "client proteins." Studies have shown that this compound can dissociate the interaction between HSP90 and its client proteins, such as HER2 and Akt, leading to their downregulation. promega.de This effect has been observed in HER2-positive breast cancer cells, where this compound selectively inhibits their growth. Furthermore, this compound has been shown to induce the degradation of HSP90 client proteins, including RET kinase, in medullary thyroid cancer cells, suggesting its broad applicability in cancers where HSP90 client proteins are crucial for survival. Unlike other HSP90 inhibitors like geldanamycin, this compound exhibits a distinct mode of action, altering the stability and proteolytic profile of HSP90.

Table 4: this compound's Interaction with HSP90

Modulation of Fatty Acid Synthase (FAS)

Table 5: this compound's Modulation of Fatty Acid Synthase

Competitive Binding to the Protease Active Site

Nelfinavir acts as a competitive inhibitor of HIV-1 protease wikipedia.orgdrugbank.compatsnap.comresearchgate.net. Its mechanism involves reversibly binding to the active site of the enzyme, thereby competing with the natural polyprotein substrates for access to this site drugbank.compatsnap.com. The rational design of this compound, as a peptidomimetic, was based on the amino acid sequence recognized by the HIV aspartyl protease, aiming to achieve tight competitive binding at the enzyme's active site wikipedia.orgmdpi.comresearchgate.net. This compound is designed to bind tightly and is not cleaved by the protease due to the presence of a hydroxyl group in its structure, mimicking a transition state intermediate, unlike the keto group found in cleavable amino acid residues wikipedia.org. This precise mode of binding contributes to its inhibitory action wikipedia.org.

Primary and Secondary Protease Mutations Conferring Resistance

Resistance to this compound is primarily conferred by specific mutations within the HIV-1 protease gene. These mutations are categorized as primary or major resistance mutations and secondary or minor mutations asm.orgnih.gov. Primary mutations directly impact drug susceptibility, while secondary mutations often occur in conjunction with primary mutations and can modulate the level of resistance or restore viral fitness biorxiv.orgasm.orgnih.gov.

Several key mutations in HIV-1 protease are associated with this compound resistance:

D30N : This is a unique and frequently observed primary resistance mutation exclusively selected by this compound biorxiv.orgasm.orgscielo.brcabidigitallibrary.org. The D30N mutation, where aspartic acid (D) at codon 30 is replaced by asparagine (N), can lead to a significant reduction in this compound's binding affinity biorxiv.org. Structural analysis indicates that this mutation alters a crucial hydrogen bond between the drug and the enzyme's 30th residue, contributing to reduced affinity and drug resistance biorxiv.org. While conferring high resistance to this compound, D30N often does not lead to cross-resistance to most other protease inhibitors and can even increase susceptibility to some, such as saquinavir and amprenavir biorxiv.orgasm.orgscielo.brcabidigitallibrary.org. However, it can also significantly reduce the catalytic activity of HIV-1 protease, leading to impaired viral fitness biorxiv.orgnih.gov.

L90M : This is another primary resistance mutation associated with this compound resistance, though it is also involved in resistance to other PIs like indinavir and saquinavir asm.orgnih.gov. The L90M mutation (leucine (L) to methionine (M) at codon 90) is less specific to this compound compared to D30N asm.org. The co-occurrence of D30N and L90M is rare, suggesting an exclusive relationship in their evolutionary selection pathways scielo.brnih.gov.

V82A/F/S/T : Mutations at codon 82 (valine (V) to alanine (A), phenylalanine (F), serine (S), or threonine (T)) are primary resistance mutations that contribute to resistance to multiple PIs, including this compound asm.orgnih.govcabidigitallibrary.org.

I84V : This mutation (isoleucine (I) to valine (V) at codon 84) is also a primary resistance mutation that can confer resistance to this compound and other PIs asm.orgnih.gov.

Table 1: Key Primary HIV-1 Protease Mutations Conferring this compound Resistance

In addition to primary mutations, a range of secondary or minor mutations can co-occur, influencing the level of this compound resistance and viral fitness biorxiv.orgasm.orgnih.gov. These mutations often occur outside the active site but can indirectly impact inhibitor binding and assist in enzyme fitness or stability nih.govacs.org. Examples of minor mutations associated with this compound resistance include M36I, M46I/L, I54V, A71V, V77I, and N88D/S biorxiv.orgasm.orghivclinic.ca.

The synergistic effects of these co-occurring mutations are crucial. While a single primary mutation might confer resistance, the accumulation of multiple mutations, both primary and secondary, can lead to higher levels of resistance and may restore viral replication capacity that might be compromised by primary resistance mutations alone biorxiv.orghivclinic.caplos.org. For instance, the N88D mutation, when present in a D30N background, can neutralize the increased susceptibility to saquinavir and amprenavir caused by D30N alone scielo.br. Studies have shown that mutations in the flexible flaps or even distal regions of the protease can affect flap dynamics, thereby influencing PI binding callutheran.edunih.govplos.org. This complex interplay of mutations allows the virus to evade inhibitors while maintaining its replicative capacity biorxiv.orgplos.org.

Table 2: Examples of Co-occurring Minor HIV-1 Protease Mutations Associated with this compound Resistance

Formation and Activity of Major Oxidative Metabolites (e.g., M8)

This compound is metabolized to one major and several minor oxidative metabolites. fda.govdrugbank.com The major oxidative metabolite is this compound hydroxy-tert-butylamide, commonly referred to as M8 (also known as AG1402). hiv.govhivclinic.caeuropa.eunih.govmdpi.comasm.org The formation of M8 is primarily catalyzed by the polymorphic cytochrome CYP2C19. asm.orgnih.govasm.orgroche-hiv.com Approximately half of the this compound drug is metabolized by CYP2C19 to M8. nih.gov

M8 possesses in vitro antiviral activity comparable to that of the parent drug, this compound. drugs.comhivclinic.cafda.govdrugbank.comasm.org At steady state, M8 circulates at appreciable levels in plasma, with its Cmax and Cmin ratios to this compound being approximately 0.43 and 0.34, respectively, and an AUC ratio of 0.39. asm.org The elimination of M8 is primarily mediated by CYP3A4. asm.orgmdpi.comasm.org The mean half-life of M8 is considerably shorter than that of this compound, typically around 0.44 hours, contributing to its parallel terminal decline with the parent drug. nih.gov

The table below summarizes the pharmacokinetic parameters for this compound and its M8 metabolite:

Effects on Cytochrome P450 Substrates and Inhibitors

This compound is a substrate for both CYP3A4 and CYP2C19. hiv.govdrugs.comhivclinic.cafda.govdrugbank.comwikipedia.org It is also a potent inhibitor of CYP3A4. hiv.govdrugs.comhivclinic.cafda.govdrugbank.comeuropa.euhres.cakegg.jpnih.govnih.gov Co-administration with drugs that are primarily metabolized by CYP3A4 can lead to increased plasma concentrations of these co-administered drugs, potentially increasing or prolonging their therapeutic and adverse effects. fda.goveuropa.euhres.ca

Conversely, potent inducers of CYP3A (e.g., rifampicin, phenobarbital, carbamazepine, St. John's wort) can significantly reduce this compound plasma concentrations, which may lead to a loss of virologic response and potential development of resistance. drugs.comeuropa.euwebmd.comdrugs.comaap.org Co-administration with rifampicin is contraindicated due to this reduction in this compound exposure. europa.eudrugs.comaap.org Omeprazole, a proton pump inhibitor, can also reduce exposure to this compound and its active metabolite M8, potentially leading to loss of virologic response and resistance. europa.eu

This compound is unlikely to inhibit other CYP isoforms at therapeutic concentrations. drugs.comfda.goveuropa.euhres.canih.gov However, co-administration with inhibitors of CYP2C19 (e.g., fluconazole, fluoxetine) may reduce the conversion of this compound to its major active metabolite M8, leading to a concomitant increase in plasma this compound levels. europa.eu

Implications for Combination Therapies

The inhibitory effect of this compound on CYP3A4 has significant implications for combination therapies. Co-administration is contraindicated with agents that are CYP3A4 substrates and have narrow therapeutic windows, such as terfenadine, astemizole, cisapride, amiodarone, quinidine, ergot derivatives, pimozide, oral midazolam, and triazolam, due to the potential for serious and/or life-threatening reactions. drugs.comfda.goveuropa.euroche-hiv.comwebmd.comdrugs.comaap.orgmedscape.commayoclinic.org

For other CYP3A4 substrates, dose reduction or consideration of alternative medications may be required. For example, co-administration with simvastatin or lovastatin can result in significant increases in their plasma concentrations, necessitating alternatives like pravastatin or fluvastatin. europa.euwebmd.comdrugs.comaap.orgmedscape.com Sildenafil concentrations can also be substantially increased, leading to a higher risk of associated adverse events. europa.euwebmd.comaap.orgmedscape.com

This compound may also affect hormonal birth control containing ethinyl estradiol or norethindrone, potentially reducing their efficacy. drugs.comwebmd.com Therefore, additional or alternative contraceptive methods should be considered. drugs.com

Genome-Wide CRISPR/Cas9-Based Screening