Editorial: multidrug resistance in cancer: pharmacological strategies from basic research to clinical issues

Anticancer Effect of Spices Used in Mediterranean Diet: Preventive and Therapeutic Potentials

Cancer is one of the leading causes of death worldwide, with almost 10 million cancer-related deaths worldwide in 2020, so any investigation to prevent or cure this disease is very important. Spices have been studied widely in several countries to treat different diseases. However, studies that summarize the potential anticancer effect of spices used in Mediterranean diet are very limited. This review highlighted chemo-therapeutic and chemo-preventive effect of ginger, pepper, rosemary, turmeric, black cumin and clove. Moreover, the mechanisms of action for each one of them were figured out such as anti-angiogenesis, antioxidant, altering signaling pathways, induction of cell apoptosis, and cell cycle arrest, for several types of cancer. The most widely used spice in Mediterranean diet is black pepper (Piper nigrum L). Ginger and black cumin have the highest anticancer activity by targeting multiple cancer hallmarks. Apoptosis induction is the most common pathway activated by different spices in Mediterranean diet to inhibit cancer. Studies discussed in this review may help researchers to design and test new anticancer diets enriched with selected spices that have high activities.

Adaptive laboratory evolution triggers pathogen-dependent broad-spectrum antimicrobial potency in Streptomyces

BACKGROUND

In the present study, adaptive laboratory evolution was used to stimulate antibiotic production in a Streptomyces strain JB140 (wild-type) exhibiting very little antimicrobial activity against bacterial pathogens. The seven different competition experiments utilized three serial passages (3 cycles of adaptation-selection of 15 days each) in which Streptomyces strain (wild-type) was challenged repeatedly to one (bi-culture) or two (tri-culture) or three (quadri-culture) target pathogens. The study demonstrates a simple laboratory model to study the adaptive potential of evolved phenotypes and genotypes in Streptomyces to induce antibiotic production.

RESULTS

Competition experiments resulted in the evolution of the wild-type Streptomyces strain JB140 into the seven unique mutant phenotypes that acquired the ability to constitutively exhibit increased antimicrobial activity against three bacterial pathogens Salmonella Typhi (NCIM 2051), Staphylococcus aureus (NCIM 2079), and Proteus vulgaris (NCIM 2027). The mutant phenotypes not only effectively inhibited the growth of the tested pathogens but were also observed to exhibit improved antimicrobial responses against one clinical multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC 1021) isolate. In contrast to the adaptively evolved mutants, only a weak antimicrobial activity was detected in the wild-type parental strain. To get molecular evidence of evolution, RAPD profiles of the wild-type Streptomyces and its evolved mutants were compared which revealed significant polymorphism among them.

CONCLUSION

The competition-based adaptive laboratory evolution method can constitute a platform for evolutionary engineering to select improved phenotypes (mutants) with increased antibacterial profiles against targeted pathogens.

Combined pH-responsive chemotherapy and glutathione-triggered photosensitization to overcome drug-resistant hepatocellular carcinoma — a SPP/JPP Young Investigator Award paper

Doxorubicin (DOX) resistance, which results in a reduced accumulation of DOX in the nucleus and hence decreased DNA damage, is a major challenge for chemotherapy against hepatocellular carcinoma. In this paper, we combined chemotherapy with photodynamic therapy (PDT) to combat DOX-resistant human hepatocellular carcinoma cells. We have prepared the polymeric micelles conjugating with DOX and zinc(II) phthalocyanine (ZnPc) through a pH-responsive hydrazone linker and a glutathione (GSH)-responsive disulfide linker, respectively. The polymeric micelles (DOX-ZnPc-micelles) exhibited a spherical shape with a size of about 98 nm diameter and showed excellent stability in aqueous solution. Due to the self-quenching of the ZnPc inside the micelles, DOX-ZnPc-micelles did not emit fluorescence upon red light irradiation. Drug release experiments verified that DOX and ZnPc could be released under acidic conditions and reducing environments, respectively. A higher concentration of DOX was internalized into DOX-resistant R-HepG2 cells through the delivery of polymeric micelles when compared with the free DOX, hence DOX-ZnPc-micelles exhibited a significant enhancement in anticancer activity. The IC[Formula: see text] value of DOX against R-HepG2 cells was found to be 21 [Formula: see text]M when combined with PDT and it was 5-fold less than that of a single treatment of DOX (102 [Formula: see text]M). The DOX-ZnPc-micelles could induce cell apoptosis and necrosis on R-HepG2 cells by combined therapeutic modalities, while these micelles induced only apoptosis on HepG2 cells. We have demonstrated that utilization of polymeric micelles can significantly enhance the cellular uptake and cytotoxicity of DOX against R-HepG2 cells when compared with free DOX. Moreover, PDT can act as an adjuvant therapeutic modality and combine with chemotherapy to further improve therapeutic efficacy. Overall speaking, DOX-ZnPc-micelles can overcome DOX resistance and induce a synergistic therapeutic effect against DOX-resistant R-HepG2 cells, hence improving the therapeutic efficacy when compared with monotherapy.

Sapitinib Reverses Anticancer Drug Resistance in Colon Cancer Cells Overexpressing the ABCB1 Transporter

The efficacy of anti-cancer drugs in patients can be attenuated by the development of multi-drug resistance (MDR) due to ATP-binding cassette (ABC) transporters overexpression. In this in vitro study, we determined the reversal efficacy of the epidermal growth factor receptor (EFGR) inhibitor, saptinib, in SW620 and SW720/Ad300 colon cancer cells and HEK293/ABCB1 cells which overexpress the ABCB1 transporter. Sapitinib significantly increased the efficacy of paclitaxel and doxorubicin in ABCB1 overexpressing cells without altering the expression or the subcellular location of the ABCB1 transporter. Sapitinib significantly increased the accumulation of [³H]-paclitaxel in SW620/AD300 cells probably by stimulating ATPase activity which could competitively inhibit the uptake of [³H]-paclitaxel. Furthermore, sapitinib inhibited the growth of resistant multicellular tumor spheroids (MCTS). The docking study indicated that sapitinib interacted with the efflux site of ABCB1 transporter by π-π interaction and two hydrogen bonds. In conclusion, our study suggests that sapitinib surmounts MDR mediated by ABCB1 transporter in cancer cells.

Repositioning Lidocaine as an Anticancer Drug: The Role Beyond Anesthesia

While cancer treatment has improved dramatically, it has also encountered many critical challenges, such as disease recurrence, metastasis, and drug resistance, making new drugs with novel mechanisms an urgent clinical need. The term “drug repositioning,” also known as old drugs for new uses, has emerged as one practical strategy to develop new anticancer drugs. Anesthetics have been widely used in surgical procedures to reduce the excruciating pain. Lidocaine, one of the most-used local anesthetics in clinical settings, has been found to show multi-activities, including potential in cancer treatment. Growing evidence shows that lidocaine may not only work as a chemosensitizer that sensitizes other conventional chemotherapeutics to certain resistant cancer cells, but also could suppress cancer cells growth by single use at different doses or concentrations. Lidocaine could suppress cancer cell growth in vitro and in vivo via multiple mechanisms, such as regulating epigenetic changes and promoting pro-apoptosis pathways, as well as regulating ABC transporters, metastasis, and angiogenesis, etc., providing valuable information for its further application in cancer treatment and for new drug discovery. In addition, lidocaine is now under clinical trials to treat certain types of cancer. In the current review, we summarize the research and analyze the underlying mechanisms, and address key issues in this area.

MRP1-Collateral Sensitizers as a Novel Therapeutic Approach in Resistant Cancer Therapy: An In Vitro and In Vivo Study in Lung Resistant Tumor

Multidrug resistance (MDR) is the main obstacle to current chemotherapy and it is mainly due to the overexpression of some efflux transporters such as MRP1. One of the most studied strategies to overcome MDR has been the inhibition of MDR pumps through small molecules, but its translation into the clinic unfortunately failed. Recently, a phenomenon called collateral sensitivity (CS) emerged as a new strategy to hamper MDR acting as a synthetic lethality, where the genetic changes developed upon the acquisition of resistance towards a specific agent are followed by the development of hypersensitivity towards a second agent. Among our library of sigma ligands acting as MDR modulators, we identified three compounds, F397, F400, and F421, acting as CS-promoting agents. We deepened their CS mechanisms in the "pure" model of MRP1-expressing cells (MDCK-MRP1) and in MRP1-expressing/drug resistant non-small cell lung cancer cells (A549/DX). The in vitro results demonstrated that (i) the three ligands are highly cytotoxic for MRP1-expressing cells; (ii) their effect is MRP1-mediated; (iii) they increase the cytotoxicity induced by cis-Pt, the therapeutic agent commonly used in the treatment of lung tumors; and (iv) their effect is ROS-mediated. Moreover, a preclinical in vivo study performed in lung tumor xenografts confirms the in vitro findings, making the three CS-promoting agents candidates for a novel therapeutic approach in lung resistant tumors.

RAC1 inhibition reverses cisplatin resistance in esophageal squamous cell carcinoma and induces downregulation of glycolytic enzymes

Development of chemoresistance remains a major challenge in treating esophageal squamous cell carcinoma (ESCC) patients despite treatment advances. However, the role of RAC1 in chemoresistance of ESCC and the underlying mechanisms remain largely unknown. In this study, we found that higher levels of RAC1 expression were associated with poorer prognosis in ESCC patients. Enhanced RAC1 expression increased cell proliferation, migration, and chemoresistance in vitro. Combination therapy using RAC1 inhibitor EHop-016 and cisplatin significantly promoted cell viability inhibition, G2/M phase cycle arrest, and apoptosis when compared to each monotherapy. Mechanistically, glycolysis was significantly downregulated in the RAC1 inhibitor monotherapy group and the combination group via inhibiting AKT/FOXO3a signaling when compared to the control group. Moreover, the silencing of RAC1 inhibited AKT/FOXO3a signaling and cell glycolysis while the upregulation of RAC1 produced an opposite effect. In murine xenograft models, the tumor volume and the expression of glycolytic enzymes were significantly reduced in combination therapy when compared to each monotherapy group. Overall, our study demonstrates that targeting RAC1 with an inhibitor overcomes cisplatin resistance in ESCC by suppressing glycolytic enzymes, which provides a promising strategy for treatment of ESCC in clinical practice.

5-Oxo-hexahydroquinoline: an attractive scaffold with diverse biological activities

5-Oxo-hexahydroquinoline (5-oxo-HHQ) represents a biologically attractive fused heterocyclic core. Various synthetic analogs of 5-oxo-HHQ have been synthesized and assessed for different biological activities. Some derivatives have exhibited myorelaxant, analgesic, anticancer, antibacterial, antifungal, antitubercular, antimalarial, antioxidant, anti-inflammatory, multidrug resistance reversal, anti-Alzheimer, neuroprotective, antidiabetic, antidyslipidemic and antiosteoporotic activities. This review provides a comprehensive report regarding the preparation and pharmacological characterization of 5-oxo-HHQ derivatives that have been reported so far. This information will be beneficial for medicinal chemists in the field of drug discovery to design and develop new and potent therapeutical agents bearing the 5-oxo-HHQ nucleus.

The dynamic role of autophagy and MAPK signaling in determining cell fate under cisplatin stress in osteosarcoma cells

Osteosarcoma (OS) is an aggressive bone malignancy commonly observed in children and adolescents. Sub-optimal therapy for years has irretrievably compromised the chances of OS patient survival; also, lack of extensive research on this rare disease has hindered therapeutic development. Cisplatin, a common anti-tumor drug, is currently an integral part of treatment regime for OS along with methotrexate and doxorubicin. However, toxicity issues associated with combination module impede OS therapy. Also, despite the proven benefits of cisplatin, acquisition of resistance remains a concern with cisplatin-based therapy. This prompted us to investigate the molecular effects of cisplatin exposure and changes associated with acquired resistance in OS cells. Cisplatin shock was found to activate MAPK signaling and autophagy in OS cells. An activation of JNK and autophagy acted as pro-survival strategy, while ERK1/2 triggered apoptotic signals upon cisplatin stress. A crosstalk between JNK and autophagy was observed. Maximal sensitivity to cisplatin was obtained with simultaneous inhibition of both autophagy and JNK pathway. Cisplatin resistant cells were further developed by repetitive drug exposure followed by clonal selection. The resistant cells showed an altered signaling circuitry upon cisplatin exposure. Our results provide valuable cues to possible molecular alterations that can be considered for development of improved therapeutic strategy against osteosarcoma.

Adaptive Laboratory Evolution of Antibiotic Resistance Using Different Selection Regimes Lead to Similar Phenotypes and Genotypes

Antibiotic resistance is a global threat to human health, wherefore it is crucial to study the mechanisms of antibiotic resistance as well as its emergence and dissemination. One way to analyze the acquisition of de novo mutations conferring antibiotic resistance is adaptive laboratory evolution. However, various evolution methods exist that utilize different population sizes, selection strengths, and bottlenecks. While evolution in increasing drug gradients guarantees high-level antibiotic resistance promising to identify the most potent resistance conferring mutations, other selection regimes are simpler to implement and therefore allow higher throughput. The specific regimen of adaptive evolution may have a profound impact on the adapted cell state. Indeed, substantial effects of the selection regime on the resulting geno- and phenotypes have been reported in the literature. In this study we compare the geno- and phenotypes of Escherichia coli after evolution to Amikacin, Piperacillin, and Tetracycline under four different selection regimes. Interestingly, key mutations that confer antibiotic resistance as well as phenotypic changes like collateral sensitivity and cross-resistance emerge independently of the selection regime. Yet, lineages that underwent evolution under mild selection displayed a growth advantage independently of the acquired level of antibiotic resistance compared to lineages adapted under maximal selection in a drug gradient. Our data suggests that even though different selection regimens result in subtle genotypic and phenotypic differences key adaptations appear independently of the selection regime.

Investigation of Antioxidative and Anticancer Potentials of Streptomyces sp. MUM256 Isolated from Malaysia Mangrove Soil

A Streptomyces strain, MUM256 was isolated from Tanjung Lumpur mangrove soil in Malaysia. Characterization of the strain showed that it has properties consistent with those of the members of the genus Streptomyces. In order to explore the potential bioactivities, extract of the fermented broth culture of MUM256 was prepared with organic solvent extraction method. DPPH and SOD activity were utilized to examine the antioxidant capacity and the results have revealed the potency of MUM256 in superoxide anion scavenging activity in dose-dependent manner. The cytotoxicity of MUM256 extract was determined using cell viability assay against 8 different panels of human cancer cell lines. Among all the tested cancer cells, HCT116 was the most sensitive toward the extract treatment. At the highest concentration of tested extract, the result showed 2.3-, 2.0-, and 1.8-folds higher inhibitory effect against HCT116, HT29, and Caco-2 respectively when compared to normal cell line. This result has demonstrated that MUM256 extract was selectively cytotoxic toward colon cancer cell lines. In order to determine the constituents responsible for its bioactivities, the extract was then subjected to chemical analysis using GC-MS. The analysis resulted in the identification of chemical constituents including phenolic and pyrrolopyrazine compounds which may responsible for antioxidant and anticancer activities observed. Based on the findings of this study, the presence of bioactive constituents in MUM256 extract could be a potential source for the development of antioxidative and chemopreventive agents.