miR-7/TGF-β2 axis sustains acidic tumor microenvironment-induced lung cancer metastasis

Acidosis, regardless of hypoxia involvement, is recognized as a chronic and harsh tumor microenvironment (TME) that educates malignant cells to thrive and metastasize. Although overwhelming evidence supports an acidic environment as a driver or ubiquitous hallmark of cancer progression, the unrevealed core mechanisms underlying the direct effect of acidification on tumorigenesis have hindered the discovery of novel therapeutic targets and clinical therapy. Here, chemical-induced and transgenic mouse models for colon, liver and lung cancer were established, respectively. miR-7 and TGF-β2 expressions were examined in clinical tissues (n = 184). RNA-seq, miRNA-seq, proteomics, biosynthesis analyses and functional studies were performed to validate the mechanisms involved in the acidic TME-induced lung cancer metastasis. Our data show that lung cancer is sensitive to the increased acidification of TME, and acidic TME-induced lung cancer metastasis via inhibition of miR-7-5p. TGF-β2 is a direct target of miR-7-5p. The reduced expression of miR-7-5p subsequently increases the expression of TGF-β2 which enhances the metastatic potential of the lung cancer. Indeed, overexpression of miR-7-5p reduces the acidic pH-enhanced lung cancer metastasis. Furthermore, the human lung tumor samples also show a reduced miR-7-5p expression but an elevated level of activated TGF-β2; the expressions of both miR-7-5p and TGF-β2 are correlated with patients' survival. We are the first to identify the role of the miR-7/TGF-β2 axis in acidic pH-enhanced lung cancer metastasis. Our study not only delineates how acidification directly affects tumorigenesis, but also suggests miR-7 is a novel reliable biomarker for acidic TME and a novel therapeutic target for non-small cell lung cancer (NSCLC) treatment. Our study opens an avenue to explore the pH-sensitive subcellular components as novel therapeutic targets for cancer treatment.

Elevated Serum Lactate in Patients With Lymphoma: It Is Not Always Infection

OBJECTIVE

To distinguish between sepsis only vs progressive lymphoma in patients with a history of lymphoma who present to the hospital with lactic acidosis.

PATIENTS AND METHODS

We identified patients with non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma from January 2014 to December 2015. Patients were categorized into 2 groups: sepsis only or progressive lymphoma. Two-sided Wilcoxon rank sum test and χ¹/Fisher exact test were used to compare the continuous and categorical variables, respectively. Kaplan-Meier analysis was used to estimate overall survival (OS).

RESULTS

A total of 51 patients were identified; 33 (65%) patients were categorized into the sepsis only group, and 18 (35%), into the progressive lymphoma group. Values for serum lactate dehydrogenase (LDH) drawn during hospitalization were statistically different between the sepsis only and progressive lymphoma groups (median, 262 vs 665 U/L; P=.005), respectively. The sensitivity and specificity of serum LDH level 2 or more times the upper limit of normal for progressive lymphoma were 56% (95% CI, 33% to 79%) and 85% (95% CI, 73% to 97%), respectively. Serum LDH level was independently predictive of inferior OS (hazard ratio, 27.8; 95% CI, 4.0 to 160.1; P<.001), while serum albumin level (hazard ratio, 0.05; 95% CI, 0.01 to 0.27; P<.001) was independently predictive of improved OS.

CONCLUSION

Serum LDH levels used in conjunction with serial serum lactate values may be reliable markers to differentiate patients with progressive lymphomatous disease from patients with lymphoma with sepsis only. The LDH levels should be obtained in all patients with lymphoma who present to the hospital with lactic acidosis.

Targeting uptake transporters for cancer imaging and treatment

Cancer cells reprogram their gene expression to promote growth, survival, proliferation, and invasiveness. The unique expression of certain uptake transporters in cancers and their innate function to concentrate small molecular substrates in cells make them ideal targets for selective delivering imaging and therapeutic agents into cancer cells. In this review, we focus on several solute carrier (SLC) transporters known to be involved in transporting clinically used radiopharmaceutical agents into cancer cells, including the sodium/iodine symporter (NIS), norepinephrine transporter (NET), glucose transporter 1 (GLUT1), and monocarboxylate transporters (MCTs). The molecular and functional characteristics of these transporters are reviewed with special emphasis on their specific expressions in cancers and interaction with imaging or theranostic agents [e.g., I-123, I-131, ¹²³I-iobenguane (mIBG), ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) and ¹³C pyruvate]. Current clinical applications and research areas of these transporters in cancer diagnosis and treatment are discussed. Finally, we offer our views on emerging opportunities and challenges in targeting transporters for cancer imaging and treatment. By analyzing the few clinically successful examples, we hope much interest can be garnered in cancer research towards uptake transporters and their potential applications in cancer diagnosis and treatment.

Understanding peroral absorption: regulatory aspects and contemporary approaches to tackling solubility and permeability hurdles

Oral drug absorption is a process influenced by the physicochemical and biopharmaceutical properties of the drug and its inter-relationship with the gastrointestinal tract. Drug solubility, dissolution and permeability across intestinal barrier are the key parameters controlling absorption. This review provides an overview of the factors that affect drug absorption and the classification of a drug on the basis of solubility and permeability. The biopharmaceutical classification system (BCS) was introduced in early 90׳s and is a regulatory tool used to predict bioavailability problems associated with a new entity, thereby helping in the development of a drug product. Strategies to combat solubility and permeability issues are also discussed.