Dysregulation of calcium homeostasis in cancer and its role in chemoresistance.

Globally, cancer, as a major public health concern, poses a severe threat to people's well-being. Advanced and specialized therapies can now cure the majority of people with early-stage cancer. However, emerging resistance to traditional and novel chemotherapeutic drugs remains a serious issue in clinical medicine. Chemoresistance often leads to cancer recurrence, metastasis, and increased mortality, accounting for 90% of chemotherapy failures. Thus, it is important to understand the molecular mechanisms of chemoresistance and find novel therapeutic approaches for cancer treatment. Among the several factors responsible for chemoresistance, calcium (Ca2+) dysregulation plays a significant role in cancer progression and chemoresistance. Therefore, targeting this derailed Ca2+ signalling for cancer therapy has become an emerging research area. Of note, the Ca2+ signal and its proteins are a multifaceted and potent tool by which cells achieve specific outcomes. Depending on cell survival needs, Ca2+ is either upregulated or downregulated in both chemosensitive and chemoresistant cancer cells. Consequently, the appropriate treatment should be selected based on Ca2+ signalling dysregulation. This review discusses the role of Ca2+ in cancer cells and the targeting of Ca2+ channels, pumps, and exchangers. Furthermore, we have emphasised the role of Ca2+ in chemoresistance and therapeutic strategies. In conclusion, targeting Ca2+ signalling is a multifaceted process. Methods such as site-specific drug delivery, target-based drug-designing, and targeting two or more Ca2+ proteins simultaneously may be explored; however, further clinical studies are essential to validate Ca2+ blockers' anti-cancer efficacy.

Interplay between dental caries pathogens, periodontal pathogens, and sugar molecules: approaches for prevention and treatment.

Globally, oral diseases affect nearly 3.5 billion people, accounting for 4.6% of the healthcare expenditure. Common oral diseases include dental caries and periodontal disease, associated with biofilms formed by cariogenic pathogens. Epidemiological studies associate carbohydrates with these diseases due to  the sugars metabolized by cariogenic pathogens. This review focuses on dental caries and periodontal pathogens, quorum sensing, lectin-carbohydrate interactions, and various sugar molecules. Cariogenic sugars significantly influence biofilms by enhancing pathogen adhesion, viability, and gene expressions associated with biofilm formation. Moreover, lectin-carbohydrate interactions contribute to biofilm stability. Disrupting these interactions is a potential strategy for oral disease prevention. The use of nanoparticles, such as quantum dots, provides novel insights into lectin-sugar interactions and the development of inhibitors. Additionally, nanomaterials like calcium phosphate nanoparticles neutralize acids and inhibit microbial growth. This overview emphasizes understanding the relationships between oral diseases, microbial communities, and sugars to devise preventive and therapeutic strategies against oral diseases.

Comparative analysis of trace elements in the saliva and serum of patients with oral submucous fibrosis and squamous cell carcinoma.

Of note, one third of oral cancer or oral tissue dysfunction cases are from India, primarily resulting from the consumption of Gutkha, a type of smokeless tobacco prevalent among several Indian populations. Gutkha is a mixture of tobacco, areca nut, slaked lime, catechu, spices, sweeteners and essences. Oral submucous fibrosis (OSMF), which is linked to the consumption of areca nut products and tobacco, is a chronic, precancerous condition of the submucosal tissues. OSMF transforms into oral squamous cell carcinoma (OSCC) at a rate of 7-13%. Gutkha also contains various trace elements, such as copper (Cu), zinc (Zn), selenium (Se) and molybdenum (Mo). Alterations in trace element levels in the body are associated with cancer progression. The present study aimed to determine the levels of serum and salivary trace elements in patients with OSMF and OSCC. A total of 80 patients were selected for the study and were divided into four groups of 20 patients in each (Group A, gutkha intake without OSMF; group B, gutkha intake with OSMF; group C, OSCC; and group D, control). The level of Cu was found to be increased and the levels of Zn, Se and Mo were decreased in the serum of patients with OSMF and OSCC compared with the controls. The salivary levels of these elements were lower compared with those in the serum. Age and sex had no significant effect on the levels of these trace elements. The results of the present study affirm the fact that serum and salivary trace elements are altered in pre-malignant and malignant lesions as the disease progresses. As the composition of saliva often varies, monitoring serum trace element levels as diagnostic and prognostic markers may aid in the early detection of the disease and in the management of the treatment efficacy.

Antibiotics Knowledge, Usage, and Prescription Patterns Among Dental Practitioners in Hyderabad, South India.

BACKGROUND: Antimicrobial resistance is a pertinent issue in the healthcare sector, accounting for 1.27 million patient deaths worldwide. Dental practitioners account for 3% to 11% of total antibiotic prescriptions. Therefore, this study aimed to specifically assess their knowledge of antibiotic prescriptions, guidelines, and clinical practices. METHOD: Before conducting this knowledge, attitude, and practice (KAP) survey, study approval was obtained from the Scientific Review Board of Saveetha Dental College and Hospitals, Chennai, India. A total of 200 participants were randomly selected from the list of Indian Dental Association (Hyderabad chapter), and dental colleges, dental conferences, and peer suggestions. We received a total of 130 responses by the end of the survey. RESULTS: The survey revealed gaps in practitioners' KAP. Of those surveyed, 83 (63.85%) of the practitioners kept themselves updated about antibiotic guidelines and news, but many (94, 72.31%) were unaware of the WHO's access, watch, reserve (AWaRe) and antimicrobial stewardship concepts (103, 79.23%). A total of 111 (85.38%) practitioners considered cross-reactions with other medications, yet only 28 (21.5%) practitioners tested patients for antibiotic sensitivity. While 64 (49.23%) practitioners encountered patients who did not respond to antibiotics, 84 (64.62%) practitioners encountered patients who demanded antibiotics. CONCLUSION: This study highlights the lack of awareness about the WHO's AWaRe classification and antimicrobial stewardship among the majority of dental practitioners across Hyderabad. Misuse or overuse of antibiotics was indicated in this survey by both patients and dental practitioners. Prioritizing updates on antibiotic knowledge and guidelines and awareness of their use is important. It is essential to educate patients about the ill effects of self-prescribing antibiotics. Dental practitioners need to consider cross-reactions and antibiotic-sensitivity testing before prescribing antibiotics. Labeling the sensitivity of a particular antibiotic for specific microbes on packaging can help reduce misuse and the use of antibiotics for the wrong indications.

Research and therapeutic applications of silk proteins in cancer.

Despite the availability of advanced treatments, cancer remains the second leading cause of death worldwide. This is due to the many challenges prevailing in the research field and cancer therapy. Resistance to therapy and side effects provide major hindrances to recovery from cancer. As a result, in addition to the aim of killing cancer cells, the focus should also be on reducing or preventing side effects of the treatment. To enhance the effectiveness of cancer treatment, many researchers are studying drug delivery systems based on silk proteins: fibroin and sericin. These proteins have high biocompatibility, biodegradability, and ease of modification. Consequently, many researchers have developed several formulations of silk proteins such as scaffolds, nanoparticles, and hydrogels by combining them with other materials or drugs. This review summarizes the use of silk proteins in various forms in cancer research and therapy. The use of silk proteins to study cancer cells, to deliver cancer drugs to a target site, in cancer thermal therapy, and as an anti-cancer agent is described here.

On-chip mixing of cancer cells and drug using LED enabled 2D opto-wetting droplet platforms.

Droplets of microliter size serve as miniaturized reaction chambers for practical lab on a chip (LoC) applications. The transportation and coalescence of droplets are indispensable for realizing microfluidic mixing. Light can be used as an effective tool for droplet manipulation. We report a novel platform for LED-based transport and mixing of cell-encapsulated microdroplets for evaluating dose response of cancer drugs. Microcontroller enabled LEDs (Light-emitting diodes) were used to actuate droplet movement on Azobenzene coated planar silicon substrates. Droplet transport was initiated by the spatial gradient in solid-liquid interfacial tension developed through LED triggered photoisomerization of Azobenzene substrate. Detailed UV-Visible characterization of Azobenzene molecule was performed for different LED light intensities and wavelengths. A complete standalone opto-wetting toolbox was developed by integrating various components such as a microcontroller, UV LED (385 nm), blue LED (465 nm), and Azobenzene coated photoresponsive substrate. 2D transport of DI water droplets (10-30µl) along simple trajectories was demonstrated using this device. Subsequently, the proposed opto-wetting platform was used for performing drug evaluation through on-chip mixing of droplets containing cancer cells (A549-Lung cancer cells) and cancer drug (paclitaxel). Separate cell viability analysis was performed using MTT assays, where the cytocompatibility of Azobenzene and UV light (385 nm) on A549 cells were studied. The dosage response of paclitaxel drug was studied using both MTT (3-(4,5-Dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide) and live-dead cell assays. The results obtained indicate the potential use of our device as a cost-effective, reliable opto-wetting microfluidic platform for drug screening experiments.

Antagonistic interaction between TTA-A2 and paclitaxel for anti-cancer effects by complex formation with T-type calcium channel.

Studies have shown that in cancer cells, there is an increased T-type calcium channel (TTCC) expression compared to healthy cells. Therefore, the studies targeting TTCC for cancer therapy have shown many positive outcomes. Here, we have used TTA-A2- a potent TTCC inhibitor as a test drug, and paclitaxel (PTX)- a tubule-binding anti-cancer agent as a positive control. Blocking TTCC has shown to overcome resistance in cancer cells towards anti-cancer drugs by reducing calcium influx, and some studies have shown that PTX treatment also reduces the intracellular calcium signaling in cells. So, there is a possibility that PTX might be interacting with calcium channels. Since, drug-drug interaction can cause severe side-effects, or alter the actions of each other; we aim to study the interactions among TTA-A2, PTX, and TTCC. In this study, we have used computational analysis to test the binding of TTA-A2 and PTX with TTCC. To confirm the in-silico result, we further tested these drugs in a 3D spheroid model of A549, a lung adenocarcinoma cell line. The in-silico result showed that both the drugs, TTA-A2 and PTX, could interact at the same site of TTCC to form a higher stable complex as compared to the TTCC-native. The in vitro result showed the antagonistic interaction between the drugs when they are used at the same time. By using the sequential treatment, the spheroids were sensitized by TTA-A2, before treating with PTX. The result indicated that sequential treatment could help to overcome the antagonistic interaction between the two drugs. Communicated by Ramaswamy H. Sarma.

Adjuvant role of a T-type calcium channel blocker, TTA-A2, in lung cancer treatment with paclitaxel.

Aim: Chemoresistance is a prevalent issue in cancer treatment. Paclitaxel (PTX) is a microtubule-binding anticancer drug used in various cancer treatments. However, cancer cells often show chemoresistance against PTX with the help of P-glycoprotein (Pgp) - a drug efflux pump. It has also been observed that overexpressed T-type calcium channels (TTCCs) maintain calcium homeostasis in cancer cells, and calcium has a role in chemoresistance. Therefore, the aim of this study was to test the adjuvant role of TTA-A2, a TTCC blocker, in enhancing the anticancer effect of PTX on the A549 lung adenocarcinoma cell line. Methods: Morphology assay, calcium imaging assay, clonogenic assay, apoptosis assay, and real-time polymerase chain reaction (real-time PCR) were performed to find the adjuvant role of TTA-A2. Samples were treated with PTX at 10 nM concentration and TTA-A2 at 50 and 100 nM concentrations. PTX and TTA-A2 were used in the combination treatment at 10 and 100 nM concentrations, respectively. Results: Immunocytochemistry confirmed the expression of TTCC in A549 cells. Morphology assay showed altered morphology of A549 cells. The adjuvant role of TTA-A2 was observed in the calcium imaging assay in spheroids, in the clonogenic assay in monolayers, and in the apoptosis assay in both cultures. With real-time PCR, it was observed that, even though cells express the mRNA of Pgp, it is non-significant upon treatment with PTX and TTA-A2. Conclusion: TTA-A2 can be used as an adjuvant to reduce chemoresistance in cancer cells as well as to enhance the anticancer effect of the standard anticancer drug PTX. Being a potent TTCC inhibitor, TTA-A2 may also enhance the anticancer effects of other anticancer drugs.

T-type calcium channel antagonist, TTA-A2 exhibits anti-cancer properties in 3D spheroids of A549, a lung adenocarcinoma cell line.

AIMS: Despite the advanced cancer treatments, there is increased resistance to chemotherapy and subsequent mortality. In lack of reliable data in monolayer cultures and animal models, researchers are shifting to 3D cancer spheroids, which represents the in vivo robust tumour morphology. Calcium is essential in cell signalling and proliferation. It is found that T-type calcium channels (TTCCs) are overexpressed in various cancer cells, supporting their increased proliferation. Many of the TTCCs blockers available could target other channels besides TTCCs, which can cause adverse effects. Therefore, we hypothesise that TTA-A2, a highly selective blocker towards TTCCs, can inhibit the growth of cancer spheroids, and provide an anti-cancer and an adjuvant role in cancer therapy. METHODS: We studied TTA-A2 and paclitaxel (PTX-control drug) in lung adenocarcinoma cell line- A549, cancer cells and human embryonic kidney cell line- HEK 293, control cell, in their monolayer and spheroids forms for viability, proliferation, morphology change, migration, and invasion-after 48-96 h of treatment. KEY FINDINGS: Though the results varied between the monolayer and spheroids studies, we found both anti-cancer as well as adjuvant effect of TTA-A2 in both the studies. TTA-A2 was able to inhibit the growth, viability, and metastasis of the cancer cells and spheroids. Differences in the results of two modes might explain that why drugs tested successfully in monolayer culture fail in clinical trials. SIGNIFICANCE: This study establishes the role of TTA-A2, a potent TTCC blocker as an anti-cancer and adjuvant drug in reducing the viability and metastasis of the cancer cells.

Cardiac voltage gated calcium channels and their regulation by ß-adrenergic signaling.

Voltage-gated calcium channels (VGCCs) are the predominant source of calcium influx in the heart leading to calcium-induced calcium release and ultimately excitation-contraction coupling. In the heart, VGCCs are modulated by the ß-adrenergic signaling. Signaling through ß-adrenergic receptors (ßARs) and modulation of VGCCs by ß-adrenergic signaling in the heart are critical signaling and changes to these have been significantly implicated in heart failure. However, data related to calcium channel dysfunction in heart failure is divergent and contradictory ranging from reduced function to no change in the calcium current. Many recent studies have highlighted the importance of functional and spatial microdomains in the heart and that may be the key to answer several puzzling questions. In this review, we have briefly discussed the types of VGCCs found in heart tissues, their structure, and significance in the normal and pathological condition of the heart. More importantly, we have reviewed the modulation of VGCCs by ßARs in normal and pathological conditions incorporating functional and structural aspects. There are different types of ßARs, each having their own significance in the functioning of the heart. Finally, we emphasize the importance of location of proteins as it relates to their function and modulation by co-signaling molecules. Its implication on the studies of heart failure is speculated.

Plumbagin, a plant-derived naphthoquinone metabolite induces mitochondria mediated apoptosis-like cell death in Leishmania donovani: an ultrastructural and physiological study.

Naphthoquinones are known to exhibit a broad range of biological activities against microbes, cancer and parasitic diseases and have been widely used in Indian traditional medicine. Plumbagin is a plant-derived naphthoquinone metabolite (5-hydroxy-2-methyl-1,4-naphthoquinone) reported to inhibit trypanothione reductase, the principal enzyme and a validated drug target involved in detoxification of oxidative stress in Leishmania. Here, we report the mechanistic aspects of cell death induced by plumbagin including physiological effects in the promastigote form and ultrastructural alterations in both promastigote and amastigote forms of Leishmania donovani which till now remained largely unknown. Our observations show that oxidative stress induced by plumbagin resulted in depolarization of the mitochondrial membrane, depletion in ATP levels, elevation of cytosolic calcium, increase in caspase 3/7-like protease activity and lipid peroxidation in promastigotes. Apoptosis-like cell death induction post plumbagin treatment was confirmed by biochemical assays like Annexin V/FITC staining, TUNEL as well as morphological and ultrastructural studies. These findings collectively highlight the mode of action and importance of oxidative stress inducing agents in effectively killing both forms of the Leishmania parasite and opens up the possibility of exploring plumbagin and its derivatives as promising candidates in the chemotherapy of Leishmaniasis.