Immunomodulatory effects of a bioactive fraction of Strobilanthes crispus in NMU-induced rat mammary tumor model

Tailoring biomaterials and applications targeting tumor-associated macrophages in cancers

Tumor-associated macrophages (TAMs) play a critical role in supporting tumor growth and metastasis, taming host immunosurveillance, and augmenting therapeutic resistance. As the current treatment paradigms for cancers are generally insufficient to exterminate cancer cells, anti-cancer therapeutic strategies targeting TAMs have been developed. Since TAMs are highly heterogeneous and the pro-tumoral functions are mediated by phenotypes with canonical surface markers, TAM-associated materials exert anti-tumor functions by either inhibiting polarization to the pro-tumoral phenotype or decreasing the abundance of TAMs. Furthermore, TAMs in association with the immunosuppressive tumor microenvironment (TME) and tumor immunity have been extensively exploited in mounting evidence, and could act as carriers or accessory cells of anti-tumor biomaterials. Recently, a variety of TAM-based materials with the capacity to target and eliminate cancer cells have been increasingly developed for basic research and clinical practice. As various TAM-based biomaterials, including antibodies, nanoparticles, RNAs, etc., have been shown to have potential anti-tumor effects reversing the TME, in this review, we systematically summarize the current studies to fully interpret the specific properties and various effects of TAM-related biomaterials, highlighting the potential clinical applications of targeting the crosstalk among TAMs, tumor cells, and immune cells in anti-cancer therapy.

Strobilanthes crispus elicits anti-tumor immunogenicity in in vitro and in vivo metastatic breast carcinoma

Plant-based anticancer agents have the potential to stimulate the immune system to act against cancer cells. A standardized bioactive subfraction of the Malaysian herb, Strobilanthes crispus (L.) Blume (S. crispus) termed F3, demonstrates strong anticancer effects in both in vitro and in vivo models. The anticancer effects might be attributable to its immunomodulatory properties as S. crispus has been traditionally used to enhance the immune system. The current study examined whether F3 could stimulate anti-tumorigenic immunogenicity against 4T1 cells in vitro and in 4T1 cell-induced mammary carcinoma mouse model. We observed that F3 induced significant increase in MHC class I and class II molecules. CD4+, CD8+ and IL-2+ (p<0.05 for all) cells infiltration was also significantly increased in the breast tumor microenvironment of F3-treated mice compared with the tumors of untreated mice. The number of CD68+ macrophages was significantly lower in F3-treated mice. We conclude that the antitumor and antimetastatic effects of S. crispus involve strong infiltration of T cells in breast cancer potentially through increased tumor antigen presentation via MHC proteins, as well as reduction of infiltrating tumor-associated macrophages.

Natural products modulating interleukins and other inflammatory mediators in tumor-bearing animals: A systematic review

BACKGROUND

Cancer is a group of diseases characterized by abnormal cell growth and proliferation. Natural products are a potentially important source for bioactive phytochemicals in the management of cancer, which regulate a broad range of biological events via the modulation of interleukins (ILs), pro- and anti-inflammatory modulators, and other cancer hallmark-mediated signaling pathways.

PURPOSE

To systematically review the literature to identify in vivo studies investigating the anticancer properties of medicinal plants and natural molecules as modulators of ILs and their related pro- and anti-inflammatory signaling markers in tumor-bearing animals.

METHODS

Articles published in English were searched, without any constraint in respect of countries. The electronic databases PubMed, Embase, Scopus, and Web of Science were used for the literature search for studies published between January 2010 and January 2022. The search terms used included medicinal plants, anticancer, antineoplasic agent, ILs, cytokine, and their combinations. A manual search to detect any articles not found in the databases was also made. The identified studies were then critically reviewed and relevant data were extracted and summarized.

RESULTS

Natural products were found to modulate ILs, including IL-1β, IL-2, IL-4, IL-6, IL-8, IL-18, IL-23, and IL-12, and interferon gamma; increase tissue inhibitor metalloprotease; decrease vascular endothelial growth factor, tumor necrosis factor alpha, granulocyte macrophage colony-stimulating factor, and nuclear factor kappa B; augment immunity by increasing the major histocompatibility complexes II and CD4+, cluster of differentiation 8 + T cell and class II trans-activator expression; and heighten the action of antioxidant enzymes, which are involved in the detoxification of free radicals and reactive oxygen species.

CONCLUSION

Natural products discussed in this review show great potential to regulate ILs and weaken associated pro- and anti-inflammatory signaling markers in tumor-bearing animals. Flavonoids, polyphenols, polysaccharides, alkaloids and tannins are important phytochemicals in the modulation of ILs, especially pro-inflammatory ones. However, in terms of future research, the importance of clinical trials to investigate their beneficial properties should be warranted.

Inhibition of Cytochrome P450s by Strobilanthes crispus Sub-Fraction (F3): Implication for Herb-Drug Interaction

BACKGROUND AND OBJECTIVE

Strobilanthes crispus Blume sub-fraction (F3) has been reported to be cytotoxic against cancer cells and to cause murine mammary tumor regression. Potential utilization of F3 as an adjuvant in breast cancer treatment to alleviate chemotherapeutic drug resistance is currently hampered by potential cytochrome P450 (CYP)-mediated herb-drug interactions (HDIs). The current study assessed the inhibitory potency of F3 towards five CYP enzymes involved in tamoxifen metabolism.

METHODS

Potential CYP inhibition by F3 was first determined using fluorescence assays, using known CYP inhibitors as reference. To further ascertain the inhibitory potency and mode of inhibition, high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) analysis of specific metabolites of a CYP probe substrate was conducted.

RESULTS

The half-maximal inhibitory concentration (IC₅₀) values indicate that F3 exhibited relatively weak inhibition on CYP2B6, CYP2C19, CYP2D6, and CYP3A4. Highest susceptibility to inhibition by F3 was observed for CYP2C9, where the IC₅₀ value from fluorescence-based assay was 35-fold higher than control. Further analysis by HPLC-MS/MS revealed relatively weak mixed-type inhibition of F3 on CYP2C9, as indicated by IC₅₀ and inhibition constant (K_I) values. The risk of clinically significant CYP2C9 inhibition by F3 was then predicted based on the attained K_I value and the presumed amount of F3 absorbed from S. crispus leaves following consumption. The calculated maximum plasma concentration to inhibition constant C_max/K_I) ratio suggests that F3 consumption could potentially result in clinically significant drug interactions with medications metabolized by CYP2C9.

CONCLUSION

Taken together, the results revealed a low probability of inhibition by F3 on CYP enzymes involved in tamoxifen metabolism. However, further in vivo investigation is necessary for potential F3 interaction with CYP2C9. The utility of a preliminary in vitro approach in the assessment of potential HDI was demonstrated in this study.

Anticancer Properties of Strobilanthes crispus: A Review

Cancer is a major cause of death worldwide, as exemplified by millions of cancer diagnoses every year. The use of chemotherapy in treating cancer has many disadvantages which include recurrence of cancer, associated with drug resistance, and severe side effects that are harmful to the patients. A better source of anticancer drugs can come from nature. Strobilanthes crispus (S. crispus) is a herbal medicinal plant that is indigenous in Madagascar and the Malay Archipelago. The plant possesses high vitamin and mineral content as well as phytochemicals—like phenols, catechins, tannins, and flavonoids—that are known to have therapeutic effects. Numerous preclinical studies have reported very versatile pharmacological effects of this plant, such as anticancer, antimicrobial, antioxidant, anti-angiogenesis, anti-diabetes, anti-ulcerogenic, and wound healing. Herein, this paper reviews the anticancer properties of S. crispus, providing information for future research and further exploration.

Triazine Derivative as Putative Candidate for the Reduction of Hormone-Positive Breast Tumor: In Silico, Pharmacological, and Toxicological Approach

Background and objectives: Breast cancer is a heterogeneous disease that poses the highest incidence of morbidity among women and presents many treatment challenges. In search of novel breast cancer therapies, several triazine derivatives have been developed for their potential chemotherapeutic activity. This study aims to evaluate the N-nitroso-N-methyl urea (NMU)-induced anti-mammary gland tumor activity of 2,4,6 (O-nitrophenyl amino) 1,3,5-triazine (O-NPAT). Methods: The in silico modeling and in vitro cytotoxicity assay were performed to strengthen the research hypothesis. For in vivo experimentation, 30 female rats were divided into five groups. Group I (normal control) received normal saline. Group II (disease control) received NMU (50 mg/kg). Group III (standard control) was treated with tamoxifen (5 mg/kg). Groups IV and V received O-NPAT at a dose level of 30 and 60 mg/kg, respectively. For tumor induction, 3 intraperitoneal doses of NMU were given at a 3-week interval, whereas all treatment compounds were administered orally for 14 consecutive days. Biochemical and oxidative stress markers were estimated for all experimental animals. DNA strand breakage alongside inflammatory markers was also measured for the analysis of inflammation. The hormonal profile of progesterone and estrogen was also estimated. Results: The test compound presented a significant reduction in organ weight and restored the hepatic and renal enzymes. O-NPAT treatments enhanced the antioxidant enzyme level of catalase (CAT), superoxide dismutase (SOD), and total sulfhydryl (TSH), with a highly significant reduction in lactate dehydrogenase (LDH) and lipid peroxidation. Also, the decrease in fragmented DNA, hormonal levels (estradiol and progesterone), and inflammatory cytokines (IL-6 and TNF-α) justified the dosage efficacy further supported by histopathological findings. Conclusion: All results indicated the anti-breast tumor activity of O-NPAT and presented its possibility of exploitation for beneficial effects in breast cancer treatment.

Antiglycolytic Activities of Strobilanthes crispus Active Fraction and its Bioactive Components on Triple-Negative Breast Cancer Cells In Vitro

BACKGROUND

Survival and progression of cancer cells are highly dependent on aerobic glycolysis. Strobilanthes crispus has been shown to have promising anticancer effects on breast cancer cells. The involvement of the glycolysis pathway in producing these effects is unconfirmed, thus further investigation is required to elucidate this phenomenon.

OBJECTIVE

This study aims to determine the effect of S. crispus active fraction (F3) and its bioactive components on glycolysis in triple-negative breast cancer cells (MDA-MB-231).

METHODS

This study utilizes F3, lutein, β-sitosterol, and stigmasterol to be administered in MDA-MB-231 cells for measurement of antiglycolytic activities through cell poliferation, glucose uptake, and lactate concentration assays. Cell proliferation was assessed by MTT assay of MDA-MB-231 cells after treatment with F3 and its bioactive components lutein, β-sitosterol, and stigmasterol. The IC50 value in each compound was determined by MTT assay to be used in subsequent assays. The determination of glucose uptake activity and lactate concentration were quantified using fluorescence spectrophotometry.

RESULTS

Antiproliferative activities were observed for F3 and its bioactive components, with IC50 values of 100 µg/mL (F3), 20 µM (lutein), 25 µM (β-sitosterol), and 90 μM (stigmasterol) in MDA-MB-231 cells at 48 h. The percentage of glucose uptake and lactate concentration in MDA-MB-231 cells treated with F3, lutein, or β sitosterol were significantly lower than those observed in the untreated cells in a time-dependent manner. However, treatment with stigmasterol decreased the concentration of lactate without affecting the glucose uptake in MDA-MB-231 cells.

CONCLUSION

The antiglycolytic activities of F3 on MDA-MB-231 cells are attributed to its bioactive components.

Strobilanthes crispus bioactive subfraction inhibits tumor progression and improves hematological and morphological parameters in mouse mammary carcinoma model

ETHNOPHARMACOLOGICAL RELEVANCE

Locally known as 'pecah batu', 'bayam karang', 'keci beling' or 'batu jin', the Malaysian medicinal herb, Strobilanthes crispus (S. crispus), is traditionally used by the local communities as alternative or adjuvant remedy for cancer and other ailments and to boost the immune system. S. crispus has demonstrated multiple anticancer therapeutic potential in vitro and in vivo. A pharmacologically active fraction of S. crispus has been identified and termed as F3. Major constituents profiled in F3 include lutein and β-sitosterol.

AIM OF THE STUDY

In this study, the effects of F3, lutein and β-sitosterol on tumor development and metastasis were investigated in 4T1-induced mouse mammary carcinoma model.

MATERIALS AND METHODS

Tumor-bearing mice were fed with F3 (100 mg/kg/day), lutein (50 mg/kg/day) and β-sitosterol (50 mg/kg/day) for 30 days (n = 5 each group). Tumor physical growth parameters, animal body weight and development of secondary tumors were investigated. The safety profile of F3 was assessed using hematological and histomorphological changes on the major organs in normal control mice (NM).

RESULTS

Our findings revealed significant reduction of physical tumor growth parameters in all tumor-bearing mice treated with F3 (TM-F3), lutein (TM-L) or β-sitosterol (TM-β) as compared with the untreated group (TM). Statistically significant reduction in body weight was observed in TM compared to the NM or treated (TM-F3, TM-L and TM-β) groups. Histomorphological examination of tissue sections from the F3-treated group showed normal features of the vital organs (i.e., liver, kidneys, lungs and spleen) which were similar to those of NM. Administration of F3 to NM mice (NM-F3) did not cause significant changes in full blood count values.

CONCLUSION

F3 significantly reduced the total tumor burden and prevented secondary tumor development in metastatic breast cancer without significant toxicities in 4T1-induced mouse mammary carcinoma model. The current study provides further support for therapeutic development of F3 with further pharmacokinetics studies.

Reversal effect of Solanum dasyphyllum against rotenone-induced neurotoxicity

We earlier reported the protective effect of Solanum dasyphyllum against cyanide neurotoxicity. In furtherance to this, we investigated the protective effect of S. dasyphyllum against rotenone, a chemical toxin that causes brain-related diseases. Mitochondria fraction obtained from the brain of male Wistar rats was incubated with various solvents (hexane, dichloromethane, ethylacetate, and methanol) extracts of S. dasyphyllum before rotenone exposure. Mitochondria respiratory enzymes (MRE) were evaluated along with markers of oxidative stress. The inhibition of MRE by rotenone was reversed by treatment with various fractions of S. dasyphyllum. The oxidative stress induced by rotenone was also reversed by fractions of S. dasyphyllum. In addition, the ethylacetate fraction of S. dasyphyllum was most potent against rotenone-induced neurotoxicity. In conclusion, S. dasyphyllum is rich in active phytochemicals that can prevent some neurotoxic effects of rotenone exposure. Further study can be done in an in vivo model to substantiate our results.

Stem Hexane Extract of Strobilanthes crispus Induces Apoptosis in Triple-Negative Breast Cancer Cell Line

Strobilanthes crispus is known to possess multiple health beneficial effects and reported to be traditionally used as medicine in several countries. This study was to investigate the anti-proliferative effects of S. crispus leaves and stem extracts on MDA-MB-231 by examining their effects on apoptosis pathway. The chemical compounds were extracted from leaves and stems using methanol followed by solvent partitioning. Two extracts were found to prevent MDA-MB-231 cell growth at the IC₅₀ of 45 μg/mL and 60 μg/mL, respectively, for leaf water (LW) and stem hexane (SH) extracts. Results showed that SH extract induces apoptosis by suppressing the protein expression of BCL-2 while the expression of pro-apoptotic proteins such as BAX and caspase nine were unchanged. Decrease of cyclin A2 in SH-treated cells suggested this effect was associated with the dysregulation of cell cycle. However, LW extract showed no effects on apoptosis and cell cycle arrest in the treated cells. Taken together, our results showed SH extract of S. crispus exhibiting their anti-proliferative activities by modulating apoptosis and cell cycle, but the underlying mechanisms exerted by LW extract requires further investigation.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) method development for screening of potential tamoxifen-drug/herb interaction via in vitro cytochrome P450 inhibition assay

Screening for potential drug-drug interaction (DDI) or herb-drug interaction (HDI) using in vitro cytochrome P450 inhibition (IVCI) assays requires robust analytical methods with high sensitivity and reproducibility. Utilization of liquid chromatography-mass spectrometry (LC-MS) for analyte quantification is often hampered by the presence of non-volatile IVCI sample buffer constituents that often results in ion suppression. In this study, to enable screening of drug interactions involving tamoxifen (TAM) metabolism using IVCI-LC-MS/MS, a liquid-liquid extraction (LLE) method was developed and optimized for sample clean-up. Utilization of chloroform as extraction solvent and adjustment of sample pH to 11 was found to result in satisfactory recovery (>70%) and low ion suppression (<19%). A LC-MS/MS method was subsequently developed and validated for simultaneous quantification of major TAM metabolites, such as N-desmethyltamoxifen (NDT), endoxifen (EDF) and 4-hydroxytamoxifen (HTF) to enable IVCI sample analysis. Satisfactory separation of E-/Z-isomers of endoxifen with peak resolution (Rs) of 1.9 was achieved. Accuracy and precision of the method was verified within the linear range of 0-50 ng/mL for NDT, 0-25 ng/mL for HTF and 0-25 ng/mL for EDF (E/Z isomers). Inhibitory potency (IC50, Ki and mode of inhibition) of known CYP inhibitors and Strobilanthes crispus extract was then evaluated using the validated method. In summary, the results demonstrated applicability of the developed LLE and validated LC-MS/MS method for in vitro screening of DDI and HDI involving TAM metabolism.

Evaluation of anti-proliferative activity of medicinal plants used in Asian Traditional Medicine to treat cancer

ETHNOPHARMACOLOGICAL RELEVANCE

The extensive biodiversity of plants in Southeast Asia and inadequate research hitherto warrant a continued investigation into medicinal plants. On the basis of a careful review of fresh medicinal plant usage to treat cancer from previous ethnobotanical interviews in Singapore and from the traditional uses of the indigenous plants, fresh leaves of seven locally grown medicinal plant species were evaluated for anti-proliferative activity.

AIM OF THE STUDY

To evaluate the anti-proliferative activity of local medicinal plant species Clausena lansium Skeels, Clinacanthus nutans (Burm. f.) Lindau, Leea indica (Burm. f.) Merr., Pereskia bleo (Kunth) DC., Strobilanthes crispus (L.) Blume, Vernonia amygdalina Delile and Vitex trifolia L.

MATERIALS AND METHOD

Fresh, healthy and mature leaves of the seven medicinal plants were harvested from various locations in Singapore and Malaysia for Soxhlet, ultrasonication and maceration extractions in three different solvents (water, ethanol and methanol). Cell proliferation assay using water soluble tetrazolium salt (WST-1) assay was performed on twelve human cancer cell lines derived from breast (MDA-MB-231, T47D), cervical (C33A), colon (HCT116), leukemia (U937), liver (HepG2, SNU-182, SNU-449), ovarian (OVCAR-5, PA-1, SK-OV-3) and uterine (MES-SA/DX5) cancer.

RESULTS

A total of 37 fresh leaf extracts from seven medicinal plants were evaluated for their anti-tumour activities in twelve human cancer cell lines. Of these, the extracts of C. lansium, L. indica, P. bleo, S. crispus, V. amygdalina and V. trifolia exhibited promising anti-proliferative activity against multiple cancer cell lines. Further investigation of selected promising leaf extracts indicated that maceration methanolic extract of L. indica was most effective overall against majority of the cancer cell lines, with best IC₅₀ values of 31.5 ± 11.4 µg/mL, 37.5 ± 0.7 µg/mL and 43.0 ± 6.2 µg/mL in cervical C33A, liver SNU-449, and ovarian PA-1 cancer cell lines, respectively.

CONCLUSION

The results of this study provide new scientific evidence for the traditional use of local medicinal plant species C. lansium, L . indica, P. bleo, S. crispus, V. amygdalina and V. trifolia in cancer treatment. These results highlight the importance of the upkeep of these indigenous plants in modern society and their relevance as resources for drug discovery.

Strobilanthes crispus inhibits migration, invasion and metastasis in breast cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Strobilanthes crispus (L.) Blume, locally known in Malaysia as "Pecah kaca" or "Jin batu", has been traditionally used for treatment of various ailments including cancer. We previously demonstrated that a standardized bioactive subfraction of S. crispus, termed as F3, possessed potent anticancer effects in both in vitro and in vivo breast cancer models.

AIM OF THE STUDY

To investigate the potential of F3 from S. crispus to prevent metastasis in breast cancer.

MATERIALS AND METHODS

The antimetastatic effects of F3 were first investigated on murine 4T1 and human MDA-MB-231 breast cancer cell (BCC) lines using cell proliferation, wound healing and invasion assays. A 4T1-induced mouse mammary carcinoma model was then used to determine the expression of metastasis tumor markers, epithelial (E)-cadherin, matrix metalloproteinase (MMP)-9, mucin (MUC)-1, nonepithelial (N)-cadherin, Twist, vascular endothelial growth factor (VEGF) and vimentin, using immunohistochemistry, following oral treatment with F3 for 30 days.

RESULTS

Significant growth arrest was observed with F3 IC₅₀ values of 84.27 µg/ml (24 h) and 74.41 µg/ml (48 h) for MDA-MB-231, and 87.35 µg/ml (24 h) and 78.75 µg/ml (48 h) for 4T1 cells. F3 significantly inhibited migration of both BCC lines at 50 μg/ml for 24 h (p = 0.018 and p = 0.015, respectively). Similarly, significant inhibition of invasion was demonstrated in 4T1 (75 µg/ml, p = 0.016) and MDA-MB-231 (50 µg/ml, p = 0.040) cells compared to the untreated cultures. F3 treatment resulted in reduced tumor growth compared to untreated mice (p < 0.01) or mice treated with tamoxifen (p < 0.05). Statistical parameters (absolute count, proportion, intensity and overall scores) indicating upregulation of E-cadherin expression were statistically significant in F3-treated compared to the untreated tumor-bearing mice. Similarly, F3 significantly reduced the expression of MMP-9, MUC1, N-cadherin, Twist, VEGF and vimentin in comparison with the TM (p < 0.01) group CONCLUSIONS: Our findings suggest that F3 exerts anti-metastatic effects independent of its cytotoxic effects, and these are supported by the increased expression of E-cadherin concurrent with downregulation of MMP-9, MUC1, N-cadherin, Twist, VEGF and vimentin expression in breast cancer.

Propofol improves the function of natural killer cells from the peripheral blood of patients with esophageal squamous cell carcinoma

Postoperative immunosuppression is associated with the recurrence and metastasis of esophageal squamous cell carcinoma (ESCC). Propofol is a commonly used intravenous anesthetic and has been reported to be associated with immunosuppression; however, little is known about its effect on innate immune cells during the postoperative period in patients with ESCC. The aim of the present study was to investigate the effects of propofol on the phenotype and cytotoxicity of natural killer (NK) cells derived from the peripheral blood of patients with ESCC. The percentage, phenotype and function of NK cells were compared between patients with ESCC and healthy volunteers using flow cytometry. NK cells were negatively sorted using magnetic beads and cocultured with propofol to assess changes in phenotype and function. The results revealed that the percentage of NK cells was significantly increased in the peripheral blood of patients with ESCC, while their activity and cytotoxicity were impaired. NK cells were successfully separated from peripheral blood in vitro and it was demonstrated that propofol enhanced their activity by influencing the expression of activating or inhibitory receptors. Furthermore, propofol was able to increase the cytotoxicity of NK cells from the peripheral blood of patients with ESCC. These results suggest that propofol is able to improve the function of NK cells in patients with ESCC and may therefore be an appropriate anesthetic for ESCC surgery.