Clinical review of alkalization therapy in cancer treatment

Overview of biodegradable materials for bone repair and osteosarcoma treatment: From bulk to scaffolds

Osteosarcoma, the most common type of malignant bone tumor that affects growing bones in teenagers and children, has become a significant challenge for medical science. The combination of chemotherapy and surgery has been the standard treatment strategy for decades. However, concerns about tumor recurrence and the toxic effects of the drugs continue to drive materials scientists to develop multifunctional scaffolds that can simultaneously support bone regeneration and prevent tumor recurrence. Emergent multifunctional scaffolds have the potential to foster essential and dynamic cellular communication, which can directly target, signal, stimulate, and enhance the body's natural bone repair response. This review emphasizes the mechanisms involved and highlights various technologies and manufacturing processes that align with the capability of these scaffolds to effectively promote bone repair, especially in the presence of osteosarcoma. Additionally, the review summarizes the current state of knowledge regarding scaffolds based on magnesium (Mg), zinc (Zn), and iron (Fe), as well as the antitumor properties of their corrosion products. The review also discusses the therapeutic potential of Mg-, Zn-, and Fe-based materials in inhibiting osteosarcoma cell proliferation. The article elaborates on the main research challenges and prospects of biodegradable materials for bone repair and osteosarcoma treatment.

In vivo MRI of breast cancer using carbonic anhydrase IX proteoglycan-like domain -targeting liposomes

Molecular imaging of breast cancer is increasingly recognized as a valuable tool for optimizing therapeutic interventions. Among potential targets for molecular imaging reporters, Carbonic Anhydrase IX (CAIX) stands out for its overexpression in tumors characterized by large hypoxic areas and aggressive phenotypes. CAIX, a transmembrane glycoprotein involved in pH regulation, displays a unique proteoglycan-like (PG) domain, not present in other isoforms, that could represent a specific target for imaging and therapy. While high sensitivity imaging techniques such as Positron Emission Tomography (PET) and optical imaging have been applied for CAIX targeting, no in vivo study utilizing Magnetic Resonance Imaging (MRI) to target CAIX has yet been reported. Herein, we address this gap by applying CAIX PG-targeting functionalized liposomes in the first in vivo MRI study on a murine model of breast cancer. TS/A cells were subcutaneously injected to generate primary tumors in mice, and targeted liposomes were delivered intravenously after 15 days. Internalization of the targeted liposomes by receptor-mediated endocytosis led to an enhanced MRI signal in the tumor region. Cytoplasmic and endosomal distribution of the liposomes' payload was observed. Conversely, non-functionalized liposomes and liposomes bearing a scrambled peptide, while entering tumor cells in smaller amounts, localized only to endosomes as expected. The findings reported herein suggest that CAIX PG domain-targeting liposomal formulations exploiting receptor-mediated endocytosis can lead to improved diagnostic capabilities and open avenues for targeted therapeutic delivery for the treatment of tumors overexpressing CAIX, particularly breast cancer.

Immunotherapy resistance in solid tumors: mechanisms and potential solutions

While the emergence of immunotherapies has fundamentally altered the management of solid tumors, cancers exploit many complex biological mechanisms that result in resistance to these agents. These encompass a broad range of cellular activities - from modification of traditional paradigms of immunity via antigen presentation and immunoregulation to metabolic modifications and manipulation of the tumor microenvironment. Intervening on these intricate processes may provide clinical benefit in patients with solid tumors by overcoming resistance to immunotherapies, which is why it has become an area of tremendous research interest with practice-changing implications. This review details the major ways cancers avoid both natural immunity and immunotherapies through primary (innate) and secondary (acquired) mechanisms of resistance, and it considers available and emerging therapeutic approaches to overcoming immunotherapy resistance.

Emerging Role of Extracellular pH in Tumor Microenvironment as a Therapeutic Target for Cancer Immunotherapy

Identifying definitive biomarkers that predict clinical response and resistance to immunotherapy remains a critical challenge. One emerging factor is extracellular acidosis in the tumor microenvironment (TME), which significantly impairs immune cell function and contributes to immunotherapy failure. However, acidic conditions in the TME disrupt the interaction between cancer and immune cells, driving tumor-infiltrating T cells and NK cells into an inactivated, anergic state. Simultaneously, acidosis promotes the recruitment and activation of immunosuppressive cells, such as myeloid-derived suppressor cells and regulatory T cells (Tregs). Notably, tumor acidity enhances exosome release from Tregs, further amplifying immunosuppression. Tumor acidity thus acts as a "protective shield," neutralizing anti-tumor immune responses and transforming immune cells into pro-tumor allies. Therefore, targeting lactate metabolism has emerged as a promising strategy to overcome this barrier, with approaches including buffer agents to neutralize acidic pH and inhibitors to block lactate production or transport, thereby restoring immune cell efficacy in the TME. Recent discoveries have identified genes involved in extracellular pH (pHe) regulation, presenting new therapeutic targets. Moreover, ongoing research aims to elucidate the molecular mechanisms driving extracellular acidification and to develop treatments that modulate pH levels to enhance immunotherapy outcomes. Additionally, future clinical studies are crucial to validate the safety and efficacy of pHe-targeted therapies in cancer patients. Thus, this review explores the regulation of pHe in the TME and its potential role in improving cancer immunotherapy.

Current hotspots and trends in cancer metabolic reprogramming: a scientometric analysis

Background

Metabolic reprogramming (MR) in cancer (CA) has been a focus of intense research in the recent two decades. This phenomenon has attracted great interest because it offers potential targets for cancer therapy. To capture the intellectual landscape of this field, we conducted a bibliometric analysis to assess the scientific output, major contributors, and trends in the MR/CA research.

Methods

We performed a systematic search using the Web of Science to retrieve articles published on MR of cancer from 2006 until 2023. The bibliometric tools such as Biblioshiny, VOSviewer, and Microsoft Excel were used to identify the most prolific authors, institutions, citation patterns, and keywords. We also used co-citation analysis to map the conceptual structure of the field and identify influential publications. Furthermore, we examined the literature by analyzing publication years, citations, and research impact factors.

Results

A total of 4,465 publications about MR/CA were retrieved. Publications on MR/CA increased rapidly from 2006 to 2023. Frontiers in Oncology published the most papers, while Cell Metabolism had the most citations. Highly cited papers were mainly published in Cancer Cell, Nature, Cell, Science and Cell Metabolism. China and the United States led the way in publications and contributed the most to MR/CA research. The University of Texas System, Chinese Academy of Sciences, and Fudan University were the most productive institutions. The profitable authors were Deberardinis Ralph J and Chiarugi Paola. The current topics included MR in tumorigenesis and progression of CA, MR of tumor cells and tumor microenvironment, the effect of MR on the CA treatment, the underlying mechanisms of MR (such as gene regulation, epigenetics, extracellular vesicles, and gut microbiota), and the modulation of MR. Some topics such as tumor microenvironment, lipid MR, circular RNA, long noncoding RNA, exosome, prognostic model, and immunotherapy may be the focus of MR/CA research in the next few years.

Conclusion

This study evaluated the global scientific output in the field of MR/CA research, analyzing its quantitative characteristics. It identified some significant and distinguished papers and compiled information regarding the current status and evolving trends of MR/CA research.

How Does Cancer Occur? How Should It Be Treated? Treatment from the Perspective of Alkalization Therapy Based on Science-Based Medicine

This review article investigates the relationship between mitochondrial dysfunction and cancer progression, emphasizing the metabolic shifts that promote tumor growth. Mitochondria are crucial for cellular energy production, but they also play a significant role in cancer progression by promoting glycolysis even under oxygen-rich conditions, a phenomenon known as the Warburg effect. This metabolic reprogramming enables cancer cells to maintain an alkaline internal pH and an acidic external environment, which are critical for their proliferation and survival in hypoxic conditions. The article also explores the acidic tumor microenvironment (TME), a consequence of intensive glycolytic activity and proton production by cancer cells. This acidic milieu enhances the invasiveness and metastatic potential of cancer cells and contributes to increased resistance to chemotherapy. Alkalization therapy, which involves neutralizing this acidity through dietary modifications and the administration of alkalizing agents such as sodium bicarbonate, is highlighted as an effective strategy to counteract these adverse conditions and impede cancer progression. Integrating insights from science-based medicine, the review evaluates the effectiveness of alkalization therapy across various cancer types through clinical assessments. Science-based medicine, which utilizes inductive reasoning from observed clinical outcomes, lends support to the hypothesis of metabolic reprogramming in cancer treatment. By addressing both metabolic and environmental disruptions, this review suggests that considering cancer as primarily a metabolic disorder could lead to more targeted and effective treatment strategies, potentially improving outcomes for patients with advanced-stage cancers.

Dietary approaches for controlling cancer by limiting the Warburg effect: a review

Cancer is a mysterious disease. Among other alterations, tumor cells, importantly, have metabolic modifications. A well-known metabolic modification commonly observed in cancer cells has been termed the Warburg effect. This phenomenon is defined as a high preference for glucose uptake, and increased lactate production from that glucose, even when oxygen is readily available. Some anti-cancer drugs target the proposed Warburg effect, and some dietary regimens can function similarly. However, the most suitable dietary strategies for treating particular cancers are not yet well understood. The aim of this review was to describe findings regarding the impact of various proposed dietary regimens targeting the Warburg effect. The evidence suggests that combining routine cancer therapies with diet-based strategies may improve the outcome in treating cancer. However, designing individualized therapies must be our ultimate goal.

Cancer-derived exosomes as novel biomarkers in metastatic gastrointestinal cancer

Gastrointestinal cancer (GIC) is the most prevalent and highly metastatic malignant tumor and has a significant impact on mortality rates. Nevertheless, the swift advancement of contemporary technology has not seamlessly aligned with the evolution of detection methodologies, resulting in a deficit of innovative and efficient clinical assays for GIC. Given that exosomes are preferentially released by a myriad of cellular entities, predominantly originating from neoplastic cells, this confers exosomes with a composition enriched in cancer-specific constituents. Furthermore, exosomes exhibit ubiquitous presence across diverse biological fluids, endowing them with the inherent advantages of non-invasiveness, real-time monitoring, and tumor specificity. The unparalleled advantages inherent in exosomes render them as an ideal liquid biopsy biomarker for early diagnosis, prognosticating the potential development of GIC metastasis.In this review, we summarized the latest research progress and possible potential targets on cancer-derived exosomes (CDEs) in GIC with an emphasis on the mechanisms of exosome promoting cancer metastasis, highlighting the potential roles of CDEs as the biomarker and treatment in metastatic GIC.

L-DOS47 Elevates Pancreatic Cancer Tumor pH and Enhances Response to Immunotherapy

Acidosis is an important immunosuppressive mechanism that leads to tumor growth. Therefore, we investigated the neutralization of tumor acidity to improve immunotherapy response. L-DOS47, a new targeted urease immunoconjugate designed to neutralize tumor acidity, has been well tolerated in phase I/IIa trials. L-DOS47 binds to CEACAM6, a cell-surface protein that is highly expressed in gastrointestinal cancers, allowing urease to cleave endogenous urea into two NH4+ and one CO2, thereby raising local pH. To test the synergetic effect of neutralizing tumor acidity with immunotherapy, we developed a pancreatic orthotopic murine tumor model (KPC961) expressing human CEACAM6. Using chemical exchange saturation transfer-magnetic resonance imaging (CEST-MRI) to measure the tumor extracellular pH (pHe), we confirmed that L-DOS47 raises the tumor pHe from 4 h to 96 h post injection in acidic tumors (average increase of 0.13 units). Additional studies showed that combining L-DOS47 with anti-PD1 significantly increases the efficacy of the anti-PD1 monotherapy, reducing tumor growth for up to 4 weeks.

Tumor alkalization therapy: misconception or good therapeutics perspective? - the case of malignant ascites

Tumor acidity has been identified as a key factor in promoting cancer progression, metastasis, and resistance. Tumor alkalization therapy has emerged as a potential strategy for cancer treatment. This article provides preclinical and clinical evidence for tumor alkalization therapy as a promising cancer treatment strategy. The potential of tumor alkalization therapy using sodium bicarbonate in the treatment of malignant ascites was studied. The concept of intraperitoneal perfusion with an alkalizing solution to increase the extracellular pH and its antitumor effect were explored. The significant extension in the overall survival of the Ehrlich ascites carcinoma mice treated with sodium bicarbonate solution compared to those treated with a sodium chloride solution was observed. In the sodium bicarbonate group, mice had a median survival of 30 days after tumor cell injection, which was significantly (p<0.05) different from the median survival of 18 days in the sodium chloride group and 14 days in the intact group. We also performed a case study of a patient with ovarian cancer malignant ascites resistant to previous lines of chemotherapy who underwent intraperitoneal perfusions with a sodium bicarbonate solution, resulting in a significant drop of CA-125 levels from 5600 U/mL to 2200 U/mL in and disappearance of ascites, indicating the potential effectiveness of the treatment. The preclinical and clinical results obtained using sodium bicarbonate perfusion in the treatment of malignant ascites represent a small yet significant contribution to the evolving field of tumor alkalization as a cancer therapy. They unequivocally affirm the good prospects of this concept.

Clinical Warburg effect in lymphoma patients admitted to intensive care unit

BACKGROUND

The Warburg effect, characterized by elevated lactate levels without tissue hypoxia or shock, has been described in patients with aggressive lymphoproliferative malignancies. However, the clinical characteristics and long-term outcomes in this population remain poorly understood.

METHODS

We retrospectively analyzed 135 patients with aggressive lymphoproliferative malignancies admitted to the ICU between January 2017 and December 2022. Patients were classified into three groups: Clinical Warburg Effect (CWE), No Warburg with High Lactate level (NW-HL), and No Warburg with Normal Lactate level (NW-NL). Clinical characteristics and outcomes were compared between the groups and factors associated with 1-year mortality and CWE were identified using multivariable analyses.

RESULTS

Of the 135 patients, 46 (34%) had a CWE. This group had a higher proportion of Burkitt and T cell lymphomas, greater tumor burden, and more frequent bone and cerebral involvement than the other groups. At 1 year, 72 patients (53%) died, with significantly higher mortality in the CWE and NW-HL groups (70% each) than in the NW-NL group (38%). Factors independently associated with 1-year mortality were age [HR = 1.02 CI 95% (1.00-1.04)], total SOFA score at admission [HR = 1.19 CI 95% (1.12-1.25)], and CWE [HR = 3.87 CI 95% (2.13-7.02)]. The main factors associated with the CWE were tumor lysis syndrome [OR = 2.84 CI 95% (1.14-7.42)], bone involvement of the underlying malignancy [OR = 3.58 CI 95% (1.02-12.91)], the total SOFA score at admission [OR = 0.81 CI 95% (0.69-0.91)] and hypoglycemia at admission [OR = 14.90 CI 95% (5.42-47.18)].

CONCLUSION

CWE is associated with a higher tumor burden and increased 1-year mortality compared to patients without this condition. Our findings underscore the importance of recognizing patients with CWE as a high-risk cohort, as their outcomes closely resemble those of individuals with lymphoma and shock, despite not requiring advanced organ support. Clinicians should recognize the urgency of managing these patients and consider early intervention to improve their prognosis.

Molecular Resonance Imaging of the CAIX Expression in Mouse Mammary Adenocarcinoma Cells

The carbonic anhydrase isoform IX (hCAIX) is one of the main players in extracellular tumor pH regulation, and it is known to be overexpressed in breast cancer and other common tumors. hCA IX supports the growth and survival of tumor cells, and its expression is correlated with metastasis and resistance to therapies, making it an interesting biomarker for diagnosis and therapy. The aim of this work deals with the development of an MRI imaging probe able to target the extracellular non-catalytic proteoglycan-like (PG) domain of CAIX. For this purpose, a specific nanoprobe, LIP_PepC, was designed by conjugating a peptidic interactor of the PG domain on the surface of a liposome loaded with Gd-bearing contrast agents. A Mouse Mammary Adenocarcinoma Cell Line (TS/A) was chosen as an in vitro breast cancer model to test the developed probe. MRI results showed a high selectivity and sensitivity of the imaging probe toward hCAI-expressing TS/A cells. This approach appears highly promising for the in vivo translation of a diagnostic procedure based on the targeting of hCA IX enzyme expression.

L-DOS47 enhances response to immunotherapy in pancreatic cancer tumor

Acidosis is an important immunosuppressive mechanism that leads to tumor growth. Therefore, we investigated the neutralization of tumor acidity to improve immunotherapy response. L-DOS47, a new targeted urease immunoconjugate designed to neutralize tumor acidity, has been well tolerated in phase I/IIa trials. L-DOS47 binds CEACAM6, a cell surface protein highly expressed in gastrointestinal cancers, allowing urease to cleave endogenous urea into two NH4+ and one CO2, thereby raising local pH. To test the synergetic effect of neutralizing tumor acidity with immunotherapy, we developed a pancreatic orthotopic murine tumor model (KPC961) expressing human CEACAM6. Our results demonstrate that combining L DOS47 with anti-PD1 significantly increases the efficacy of anti-PD1 monotherapy, reducing tumor growth for up to 4 weeks.

Association between pH regulation of the tumor microenvironment and immunological state

The tumor microenvironment (TME) is characterized by interactions among various cells, including tumor cells, immune cells, stromal cells, and blood vessels mediated by factors such as cytokines and metabolites. The development of cancer immunotherapy in recent years has facilitated a more comprehensive understanding of the TME. The TME changes with cancer type and host immune status, as well as with therapeutic intervention. However, studies on pH regulation of the TME have been mostly based on lactate, a metabolite of tumor cells. Notably, the Warburg effect results in the increased production of secreted lactate, thereby acidifying the extracellular microenvironment and affecting the surrounding cells. Lactate inhibits the activation and proliferation of CD8+ T cells, M1 macrophages, natural killer (NK) cells, and dendritic cells, contributing to tumor cell immune escape. It is also involved in angiogenesis and tissue remodeling, as well as promotes tumor growth and invasion. In this review, we have discussed the lactate-based pH regulation in tumor cells in the TME and its effects on the other constituent cells.

Effects of alkalization therapy on hepatocellular carcinoma: a retrospective study

Background

In hepatocellular carcinoma (HCC) patients, is difficult to prevent recurrence even when remission is achieved. In addition, even with the advent of drugs that are effective for the treatment of HCC, a satisfactory extension of patient survival has not been achieved. To overcome this situation, we hypothesized that the combination of alkalization therapy with standard treatments will improve the prognosis of HCC. We here report the clinical results of HCC patients treated with alkalization therapy at our clinic.

Patients and methods

Patients with HCC treated at Karasuma Wada Clinic (in Kyoto, Japan), from January 1, 2013, to December 31, 2020 were analyzed. Overall survival (OS) from both the time of diagnosis and the start of alkalization therapy for each patient was compared. The mean urine pH was also calculated as a surrogate marker of tumor microenvironment pH, and OS from the start of alkalization therapy was compared between patients with a mean urine pH of ≥ 7.0 and those with a mean urine pH of < 7.0.

Results

Twenty-three men and six women were included in the analysis, with a mean age at diagnosis of 64.1 years (range: 37-87 years). Seven of the 29 patients had extrahepatic metastases. Patients were divided into two groups according to their mean urine pH after the initiation of alkalization therapy: 12 of the 29 patients had a mean urine pH of ≥ 7.0, and 17 had a mean urine pH of < 7.0. The median OS from diagnosis was 95.6 months (95% confidence interval [CI] = 24.7-not reached), and from the start of alkalization therapy was 42.3 months (95% CI = 8.93-not reached). The median OS from the start of alkalization therapy in patients with a urine pH of ≥ 7.0 was not reached (n = 12, 95% CI = 3.0-not reached), which was significantly longer than that in patients with a pH of < 7.0 (15.4 months, n = 17, 95% CI = 5.8-not reached, p < 0.05).

Conclusions

The addition of alkalization therapy to standard therapies may be associated with more favorable outcomes in HCC patients with increased urine pH after alkalization therapy.

The Prime and Integral Cause of Cancer in the Post-Warburg Era

Back to beginnings. A century ago, Otto Warburg published that aerobic glycolysis and the respiratory impairment of cells were the prime cause of cancer, a phenomenon that since then has been known as "the Warburg effect". In his early studies, Warburg looked at the effects of hydrogen ions (H+), on glycolysis in anaerobic conditions, as well as of bicarbonate and glucose. He found that gassing with CO2 led to the acidification of the solutions, resulting in decreased rates of glycolysis. It appears that Warburg first interpreted the role of pH on glycolysis as a secondary phenomenon, a side effect that was there just to compensate for the effect of bicarbonate. However, later on, while talking about glycolysis in a seminar at the Rockefeller Foundation, he said: "Special attention should be drawn to the remarkable influence of the bicarbonate…". Departing from the very beginnings of this metabolic cancer research in the 1920s, our perspective advances an analytic as well as the synthetic approach to the new "pH-related paradigm of cancer", while at the same time addressing the most fundamental and recent changing concepts in cancer metabolic etiology and its potential therapeutic implications.